Search

Here the mild and simple enzymatic hydrolysis was developed to prepare the plant polysaccharides with the high purity. The pepsin (endopeptidase) and koplase (telopeptidase) were used as the complex enzymes. Kinetic models were established for the enzymatic hydrolysis. Water extraction was used to prepare the polysaccharide at 45 ℃ and 90 ℃. Also included are pepsin extraction and double enzyme extraction. Nutritional components of polysaccharides extracted by these four methods were characterized by their structure (monosaccharide composition, infrared spectrum, thermal features, low field nuclear magnetic field, and dynamic thermomechanical properties). In this paper, the kinetic models of single enzyme (pepsin)/and double enzyme segmental hydrolysis were constructed respectively. The highest contents of polyphenols (0.42±0.008 mg/mL) and uronic acid (15.65%±0.98%) were obtained in the polysaccharide of lotus seed that extracted by double enzyme. While the lowest protein content (0.73%±0.24%) was found. Among them, uronic acid was a derivative of sugar. The high contents of uronic acid and galactose were detected in all the polysaccharides that extracted from lotus seed, indicating the acidic polysaccharide. Glc, Ara, Man and Rha were contained in the four kinds of lotus seed polysaccharides, among which more Gal-UA and Man were found in the polysaccharides that extracted by double enzyme, which were 10.700 and 10.752% respectively. This acidic polysaccharide was benefit to the dissolution of active polysaccharide. The four samples of lotus seed polysaccharide also shared the similar infrared spectral characteristic peaks, αtype pyranose. The wider characteristic peaks of 1654 cm-1 were observed in 45 ℃ water extraction, indicating the more bound water. The double enzyme was also used to break the binding between polysaccharide and protein. The highest content of bound water was detected with the less fixed and free water in the double enzyme after water distribution analysis. It infers that the double enzyme extraction was more beneficial to the stability of polysaccharide structure. In addition, only the first-order relaxation was found in the polysaccharide of lotus seed that treated by double-enzyme. The energy storage modulus and loss modulus were also higher than before. The glass transition temperature was dropped to about 60℃ (close to that of plant polysaccharide). In summary, the double enzyme extraction can be expected to effectively reduce the protein content and Tg of lotus seed polysaccharide, compared with conventional methods. The content of bound water and hydrophilic ability were improved to extract the active components. The specific gravity values of polysaccharide aldehyde and rehydration were also improved for the purity of polysaccharide. The kinetic model of enzymatic hydrolysis can also provide the theoretical support to the purification of lotus seed polysaccharides, in order to understand the degradation of lotus seed protein. The two enzyme extractions can share the stronger specificity and simple steps, compared with the high-temperature ones. The mannan polysaccharide components can be extracted to improve the polysaccharide purity. Therefore, the enzymatic hydrolysis of lotus seed polysaccharide can ensure the protein to release from the polysaccharide. The effective and moderate hydrolysis can be achieved for the synchronous separation of protein and polysaccharide in the step of polysaccharide alcohol precipitation. The mathematical models were further simulated and validated, according to the mechanism of enzymolysis reaction. The kinetic models of enzymatic hydrolysis with single and double enzymes were also established to determine and characterize the nutritional structure of polysaccharide products between the low/high temperature extraction and low temperature enzymolysis. This finding can also provide the theoretical guidance for the further development and utilization of animal and plant polysaccharides. [ABSTRACT FROM AUTHOR]

In the process of wheat storage, rice weevil is a kind of extremely harmful moth-eaten pest, which belongs to the hidden pest that eats inside the grain, and in the growth and development process of rice weevil ( egg stage, larva stage, pupa stage, adult stage), there are different degrees of damage to wheat until the adult stage is drilled out. In severe cases, wheat grains can be eaten into empty shells, and the excrement is left inside the grains, which seriously damages the protein quality of wheat and affects the quality of flour. In order to explore the effects of rice weevil infection on wheat protein quality at different stages. In this paper, the crude protein, uric acid, protein components, wet gluten, gluten water absorption, lactic acid solvent retention capacity (SRC), sucrose SRC, sulfhydryl (-SH), disulfide bond (-S-S-), protein secondary structure, gluten protein microstructure of the wheat infected by rice weevil and the color and texture characteristics of the corresponding whole wheat noodles were measured and analyzed. The results showed that the growth and development of rice weevil in wheat and the damage of wheat would cause a series of changes in wheat protein, which was manifested in the deterioration of physical and chemical properties and morphological structure. With the growth and development of rice weevil inside the wheat kernels, the content of crude protein in wheat grains increased significantly, the content of wet gluten, gluten water absorption, lactic acid solvent retention SRC, sucrose SRC, -SH and-SS-decreased, The proportion of wheat protein components and secondary structures, which are very important for wheat, also changed significantly ( P<0.05 ), and the edible quality and nutritional value of wheat also decreased. The microstructure of gluten protein showed that with the growth and development of rice weevil in wheat grains, the surface roughness of gluten increased, and the fracture surface and burr increased. After reaching the adult stage, some gluten structures had been seriously broken and could not be identified. After making whole wheat noodles, the color of noodles deepened, L* value and cooking loss rate increased, a* value, b* value, hardness, adhesion, elasticity, cohesiveness, chewiness and resilience decreased. The experimental results further elucidated the deterioration mechanism of wheat damaged by rice weevil, and provided a theoretical basis for the quality improvement of wheat during storage and the insect infected wheat. [ABSTRACT FROM AUTHOR]

Bovine blood is one of the main by-products of bovine slaughtering and processing. The preparation and antioxidant activity of bovine blood peptides has been investigated systematically to promote their high-end value in industrial utilization. Taking the bovine hemoglobin (BH) as the raw material, this study aims to prepare the BH antioxidant peptide crude product using two-step hydrolysis. The reference indexes were taken as the hydrolysis degree and the ABTS·free radical scavenging ability. Six proteases were also employed for the hydrolysis to identify and select the optimal protease. Specifically, a systematic evaluation was made to investigate the effect of different solid-liquid ratios, enzyme concentration, reaction temperature, pH value, and reaction time on the initial hydrolysate, including antioxidant activity using ABTS·free radical scavenging. The remaining five proteases were used to further hydrolyze the first BH hydrolysate, where the optimal protease was selected for the single-factor test. Furthermore, the influencing parameters were assessed during enzymolysis on the antioxidant capacity of the bovine hemoglobin second hydrolysate. The results showed that: 1) The best effect was found in the first enzymatic hydrolysis of flavorzyme among the six proteases. The highest hydrolysis degree and the ABTS·scavenging ability were also observed in the first BH hydrolysate (P<0.05); 2) The BH was hydrolyzed at pH value is 7.5 and 50 ℃ for 120 min, when the solid-liquid ratio and flavorzyme content were 40 g/L and 4 000 U/g, respectively, indicating the highest antioxidant capacity of the first hydrolysate; 3) The alcalase demonstrated the best second enzymatic hydrolysis effect; 4) The BH first hydrolysate was hydrolyzed (pH values are 9.0; 40 ℃; 60 min), when the concentration of alcalase was 3 000 U/g. While the hydrolysis degree (46.06%±0.08%) and ABTS free radical scavenging ability (314.15±1.09) µmol TE/g protein) of the second hydrolysate were significantly higher than other protease groups (P<0.05). The single-factor test show that the enzyme concentration and reaction time were further optimized using the response surface method (RSM), with the ABTS free radical scavenging ability as the response value. Furthermore, the regression equation was obtained after RSM optimization, indicating the enzyme concentration and reaction time on the antioxidant capacity of the BH hydrolysate. The optimal parameters were achieved to prepare the BH antioxidant peptide crude product with the solid-liquid ratio of 40 g/L. The first enzymatic hydrolysis included: Amount of flavorzyme is 3 800 U/g, enzymatic hydrolysis time is 130 min, temperature is 50 ℃, and pH value is 7.5, while the second enzymatic hydrolysis process included: Amount of alcalase is 2 900 U/g, time is 60 min, temperature is 40℃, and pH value is 9.0. The ABTS free radical scavenging ability was achieved at (333.62±6.29) µmol TE/g protein, indicating excellent scavenging capacity and antioxidant activity. A systemic and effective procedure was obtained to extract the food-derived antioxidant peptides. The finding can provide new insight into the comprehensive processing and utilization of by-products, not limited to the bovine blood. A theoretical basis was also offered for the research and development of food-derived antioxidant peptides. [ABSTRACT FROM AUTHOR]

Protein-rich food has been the ever increasing demand with the growth of the world population. Animal meat protein that is provided by the traditional breeding industry will be difficult to meet human needs. Alternatively, plant protein can be expected to serve as the demand for protein, due to the higher yield and wider resources. Therefore, the plant-based meat products can be used to partially replace animal meat with plant protein using modern processing technology. It is of great significance in sustainable development, low carbon emission reduction, and nutritional demand. Among them, peas are widely used in the food industry, because of their high yield, high nutritional value, and low cost. The pea protein can be taken as the raw material in plant-based meat products using high water extrusion technology (moisture content of 40%–80%). The products are also closer to the texture quality of animal meat. However, pea protein isolate (PPI) from various sources varied greatly, in terms of both quality and functional characteristics. It is unclear on the high moisture extrusion qualities, which made it difficult to produce the pea protein in the plant-based meat substitutes. In this study, five commercial PPIs were selected to evaluate the variations, in terms of component content, particle size, solubility, gelation, and high moisture extrusion properties at 2 different cooling temperatures (65°C, and 90°C). The findings revealed that the quality and functional properties of PPI, as well as the cooling temperature, were connected to the quality of the extrudates. The PPI with high solubility (21.24%-25.51%) and strong gelation (0.84-1.14 N) was more advantageous to the fiber structure development (fibrous degree>1.5). At the lower cooling temperature, the solubility and extrudates’ hardness, and chewiness were a very significant positive correlation (P<0.01), and the fibrous degree was significantly positively (P<0.05) related to the solubility, indicating that the higher solubility of protein raw material had improved the hardness, chewiness, product, and fibrous degree. At high cooling temperatures, the solubility of the springiness of the extrudate was very significant positive correlated (P<0.01), the fibrous degree was a significant positive correlation (P<0.05), the gel strength and the rigidity of the extrudate were significantly negative correlation (P<0.05), very significant positive correlation (P<0.01) on the organization, indicating the solubility and gel strength influencing the extrusion quality. Besides, the moisture, protein, fat, and ash content were not correlated with the extrudates’ fibrous degree at a lower temperature, while the high temperature after the extrudates’ fibrous degree was a very significant positive correlation with the moisture and protein (P<0.01), correlated with the fat (P<0.05), and the ash content was a significantly negative correlation (P<0.05). Consequently, there was a significant correlation between the content of water, protein, fat, and ash, as well as the quality of extruded materials. as the cooling temperature changed. In addition, 90℃ cooling temperature was more conducive to the increase of new covalent bonds, promoting protein aggregation. The surface hydrophobicity analysis showed that the extrusion process resulted in the increase of hydrophobic groups, and then promoted protein aggregation. The secondary structure showed that the increasing cooling temperature increased the proportion of the β-folding structure and the formation of the fiber structure. This finding can provide the theoretical basis for the selection of raw materials at the cooling and forming temperature for plant-based meat products that are prepared by high moisture extrusion technology. A strong reference can be offered for the product development and quality improvement of new plant-based meat products. [ABSTRACT FROM AUTHOR]

Methanotroph bacteria meal (MBM) is one type of single-cell protein produced by Methylococcus capsulatus. The greenhouse gas methane can be taken as the sola carbon source, similar to the protein content and amino acid composition of the fish meal. Cottonseed meal (CSM) is a reliable plant protein source with more than 60% protein content by removing some fiber from cottonseed. According to the amount of MBM in the previous experiment, this study aims to improve intestinal health and the safe application range of CSM in the fishmeal replacement for fish. A complex protein (MC) mixed with the 4% MBM and 12% CSM was formulated and then used in the hybrid grouper’s feed. An investigation was made to clarify the effects of MC in the fishmeal-reducing diet on the growth performance, body composition, serum biochemical indices, liver and intestinal histomorphology, and the intestinal microflora of Epinephelus fuscoguttatus ♀×E. lanceolatus ♂. An 8-week feeding trial was conducted with the 180 healthy juvenile grouper in six tanks (30 fish in each tank, and 3 tanks in each group) at an average weight of (28.85 ± 0.04) g. Two iso-nitrogenous and lipid diets were formulated to contain a control group (FM group) with 40% fishmeal as the basic protein source, and an experimental group (MC group) that reduced the fishmeal content to 30% and added the MC (consisting of 4% MBM and 12% CSM) to balance the protein content. The results showed that there was no significant difference in the weight gain rate, specific growth rate, survival rate, feed conversion ratio, feed intake rate, fatness, viscera/body index, and liver/body index in the two groups. The moisture of whole fish in the FM group was higher than that in the MC group. The contents of alanine, histidine and arginine in muscle were significantly lower than those in the MC group, whereas, the content of proline in muscle was significantly higher than that in the MC group. The contents of serum triglyceride, total cholesterol, aspartate aminotransferase activity, and liver malondialdehyde in the MC group were significantly lower than those in the FM group. The total intestinal antioxidant capacity in the MC group was significantly higher than that in the FM group, whereas, the length of intestinal villi was significantly longer, and the intestinal wall thickness was significantly lower than that in the FM group. 16s rDNA sequencing results showed that the Chao1 and ACE indexes of alpha diversity of intestinal microbiota in the MC group were lower than those in the FM group, while the Shannon and Simpson indexes were higher than those in the FM group. There was a variation in the structure of intestinal microflora in the two groups. In the MC group, the relative abundance of Proteobacteria decreased at the phylum level, and the relative abundance of Alpharoteobacteria and Deltaroteobacteria increased, whereas, the relative abundance of Gammaroteobacteria decreased at the class level, while the total abundance of Vibrio, Photobacterium and Aeromonas decreased at the genus level. The microbial functional taxa predicted that the potential pathogen taxa decreased in the MC group. The KEGG pathways enrichment analysis of intestinal microflora genes showed that the MC group presented a much higher enrichment in the metabolism and organic system than the FM group, but a lower enrichment in the cell process and environmental information processing. To sum up, there was no negative effect on the juvenile grouper’s survival, the growth and feed utilization feeding MC added in the fish meal-reducing diet. There was a significant increase in the dry matter of whole fish, in order to improve the antioxidant capacity of the liver and intestine. The intestinal morphological development was stimulated to enhance the intestinal microbial richness, and then to reduce the pathogenic bacteria abundance for a stable intestinal microflora. Anyway, the optimal strategy can be the complex protein mixed with the MBM and CSM used in a fishmeal-reducing diet for the juvenile hybrid grouper. As such, the utilization efficiency of protein sources can be improved by the optimal combination. Methanotroph bacteria meal (MBM) is one type of single-cell protein produced by Methylococcus capsulatus. The greenhouse gas methane can be taken as the sola carbon source, similar to the protein content and amino acid composition of the fish meal. Cottonseed meal (CSM) is a reliable plant protein source with more than 60% protein content by removing some fiber from cottonseed. According to the amount of MBM in the previous experiment, this study aims to improve intestinal health and the safe application range of CSM in the fishmeal replacement for fish. A complex protein (MC) mixed with the 4% MBM and 12% CSM was formulated and then used in the hybrid grouper’s feed. An investigation was made to clarify the effects of MC in the fishmeal-reducing diet on the growth performance, body composition, serum biochemical indices, liver and intestinal histomorphology, and the intestinal microflora of Epinephelus fuscoguttatus ♀×E. lanceolatus ♂. An 8-week feeding trial was conducted with the 180 healthy juvenile grouper in six tanks (30 fish in each tank, and 3 tanks in each group) at an average weight of (28.85 ± 0.04) g. Two iso-nitrogenous and lipid diets were formulated to contain a control group (FM group) with 40% fishmeal as the basic protein source, and an experimental group (MC group) that reduced the fishmeal content to 30% and added the MC (consisting of 4% MBM and 12% CSM) to balance the protein content. The results showed that there was no significant difference in the weight gain rate, specific growth rate, survival rate, feed conversion ratio, feed intake rate, fatness, viscera/body index, and liver/body index in the two groups. The moisture of whole fish in the FM group was higher than that in the MC group. The contents of alanine, histidine and arginine in muscle were significantly lower than those in the MC group, whereas, the content of proline in muscle was significantly higher than that in the MC group. The contents of serum triglyceride, total cholesterol, aspartate aminotransferase activity, and liver malondialdehyde in the MC group were significantly lower than those in the FM group. The total intestinal antioxidant capacity in the MC group was significantly higher than that in the FM group, whereas, the length of intestinal villi was significantly longer, and the intestinal wall thickness was significantly lower than that in the FM group. 16s rDNA sequencing results showed that the Chao1 and ACE indexes of alpha diversity of intestinal microbiota in the MC group were lower than those in the FM group, while the Shannon and Simpson indexes were higher than those in the FM group. There was a variation in the structure of intestinal microflora in the two groups. In the MC group, the relative abundance of Proteobacteria decreased at the phylum level, and the relative abundance of Alpharoteobacteria and Deltaroteobacteria increased, whereas, the relative abundance of Gammaroteobacteria decreased at the class level, while the total abundance of Vibrio, Photobacterium and Aeromonas decreased at the genus level. The microbial functional taxa predicted that the potential pathogen taxa decreased in the MC group. The KEGG pathways enrichment analysis of intestinal microflora genes showed that the MC group presented a much higher enrichment in the metabolism and organic system than the FM group, but a lower enrichment in the cell process and environmental information processing. To sum up, there was no negative effect on the juvenile grouper’s survival, the growth and feed utilization feeding MC added in the fish meal-reducing diet. There was a significant increase in the dry matter of whole fish, in order to improve the antioxidant capacity of the liver and intestine. The intestinal morphological development was stimulated to enhance the intestinal microbial richness, and then to reduce the pathogenic bacteria abundance for a stable intestinal microflora. Anyway, the optimal strategy can be the complex protein mixed with the MBM and CSM used in a fishmeal-reducing diet for the juvenile hybrid grouper. As such, the utilization efficiency of protein sources can be improved by the optimal combination. [ABSTRACT FROM AUTHOR]

Cereals are very valuable food sources of healthy and sustainable protein. Food innovations in cereal protein are ever transitioning to more sustainable food systems for healthy diets. A more precise understanding is required by the functions that cereal proteins have. The application of cereal proteins has greatly contributed to genomics and food science today. In this study, a functional prediction was proposed for the cereal proteins using a multilayer functional structure, in order to select the functional proteins more conveniently and accurately. A large-scale interaction network was also constructed with the indica, japonica, wheat, maize, and soybean data. Firstly, the relevant functions of unknown proteins were explored via the interaction of functional features of clusters with the unknown proteins. Secondly, new protein weights, semantic similarity, and functional hierarchy weights were defined to determine the possible functions of proteins. Finally, the grain protein function was further determined using a scoring mechanism in the prediction of the function. The results show that better performance was achieved to predict the function of cereal proteins, particularly with a precision of about 77% for the accurate protein function prediction and up to 92% for the fuzzy protein function prediction using retraceability. A great contribution was made to determine the functional range of unknown proteins, especially with the high efficiency of prediction. The precision of protein function prediction varied significantly at different levels, with an average precision of 92% at level-1, 85% at level-2, and 69% at the level-4. More importantly, the average precision was close to 80% in all six levels of FunCat. As such, the multi-layer functional structure of proteins was predicted to calculate the number of unknown proteins with different sizes. The precision of the prediction was 76% at an unknown protein size of 50, 72% at an unknown protein number of 100, and 66% at an unknown protein number of 200. There was no sharp decrease with the significant increase in the prediction size. It infers that the prediction still performed the best in the case of large-scale unknown proteins. A comparison was made with the latest algorithms, such as FUNPRED_SEQSIN, DAC (Diffusion Alignment Coefficient), and PILL (Predict protein function using Incomplete hierarchical LabeLs). In terms of precision, recall, and F-measured, the performance of the improved prediction was significantly better than the others. The experimental results show that 1) the prediction can be expected to serve as the predicted function hierarchical, particularly for the protein with the specified function, or the available protein functions of specified functional levels; 2) The average precision of the cereal protein function in the first four layers of FunCat (Functional Catelogue) can reach more than 80%, even to realize the prediction of the fifth and sixth layers of the protein; 3) The retrospective nature of the hierarchy can allow the functions with the low predictions to be returned to the higher level functions. As such, the probability of false positives was reduced to improve the overall prediction accuracy. The finding can also provide a strong reference to the protein function prediction in the food industry. [ABSTRACT FROM AUTHOR]

Carrot Antifreeze Proteins (CaAFPs) are characterized by the unique anti-recrystallization capacity for potential uses in the food industry. In this study, a systematic investigation was conducted to explore the effect of CaAFPs on the properties of subfrozen dough under different freeze-thaw cycles, in order to determine if -12℃ suitable for the frozen dough storage and the state. The CaAFPs were added to the dough at a proportion of 0.5%. The dough without CaAFPs was used as the control. Three kinds of storage temperatures were set as 4℃ refrigerated, -12℃ subfrozen, and -18 ℃ frozen. The freeze-thaw was taken as the auxiliary means to measure the freezable water content, texture, and pH under the different conditions of moisture content and water loss rate. Significance analysis was then made to compare the freeze-thaw CaAFPs under the influence mechanism of the frozen dough properties. The results showed that the water loss rate of the dough in the control group showed an increasing trend in the different degrees (P<0.05) after five freeze-thaw cycles. The addition of CaAFPs greatly contributed to delaying the water loss of the dough, indicating a decrease in the water loss rate in all groups. The water content of the control group showed a decreasing trend in the different degrees (P<0.05). The water content was higher than that of the control group after adding CaAFPs (P<0.05) under freeze-thaw. An increasing trend was found in the freezable water content of the dough in the control group in the different degrees (P<0.05) under freeze-thaw. The addition of CaAFPs posed a certain protective effect on the network structure of the dough, indicating the decrease in the freezable water content. There was an upward trend (P<0.05) for the hardness and gumminess in the control group, whereas, a downward trend was the springing, cohesiveness, and chewiness (P<0.05) under freeze-thaw. After adding CaAFPs, the texture characteristics of the dough were improved significantly to more slowly adjust the texture. The pH of the dough showed a decreasing trend in the different degrees (P<0.05) in the control group. The acidification of dough was delayed for the smaller pH change trend of dough, when adding CaAFPs. In general, the moisture content of dough decreased with the increase of freeze-thaw time, where the water loss rate and the content of freezable water increased significantly, the pH value decreased, and the texture was difficult to say. But the opposite trend occurred, as the temperature dropped. Among them, -12℃ and -18 ℃ were significantly better than 4℃. There was no significant difference between them in the first two times of freeze-thaw, but after three times of freeze-thaw, -18℃ was obviously better than -12℃. The findings can provide a strong reference for the application of CaAFPs in the frozen dough and the optimization of freezing storage temperature. As such, the dough can be maintained excellent properties at -12℃ in the sub-freezing storage. Therefore, the dough can be expected to store at -12℃ for energy saving under the better state. At the same time, a new research idea can be offered for the properties of antifreeze proteins in the subfreezing state. [ABSTRACT FROM AUTHOR]

Food waste has been an international problem in recent years, due to odor and disposal challenges. Globally, the United Nations Environment Program (UNEP) estimated that about 17% of food was wasted at the retail and consumer levels. It was estimated that 91 million tons of food waste were produced in China in 2020. Fortunately, it is a promising way to convert carbon and nutrients (N, P, and K) in food waste into usable products. The multiple benefits can then be gained for nutrient recycling, public health, and reduction in the emission of greenhouse gases. However, the available cost-effective techniques are still lacking in food waste treatment, particularly in the ever-increasing demand. This research aimed to assess the potential performance of the black soldier fly (Hermetia illucens L.) for food waste (rice with spicy soup) treatment and nutrient recycling. A series of cultural experiments were indoor simulated to investigate the effects of exogenous enzymes (amylase and catalase) and capsaicin on the degradation of food waste and the growth of black soldier fly (Hermetia illucens L.) at different life phases (the first, second, and fifth instar larvae). Nevertheless, there was a low performance of the newly hatched larvae of the black soldier fly (Hermetia illucens L.) to decompose the rice residue with the spicy soup. The amylase was then added to accelerate the decomposition of starch in the food waste into sugars. A favorable condition was created for the newly hatched larvae to grow. The life phases were also selected as the second or fifth instar larvae, where the insects were in rapid growth or at mature stages. Furthermore, capsaicin was added as a seasoner to stimulate the appetite of the black soldier fly (Hermetia illucens L.), thereby increasing the food intake for the higher growth rate and biomass accumulation during this time. The addition of α-amylase (at the ratio of food waste: α-amylase of 10 000:1) and catalase (at the ratio of food waste: peroxidase of 100 000:1) at the first instar larvae of the black soldier fly (Hermetia illucens L.), followed by adding the capsaicin (at the ratio of food waste: capsaicin of 80:1) at the fifth instar larvae, increased the degradation rate of food waste by 6.49 %, the live weight of the insect by 29.70 %, and the dry weight of the insect by 38.22 %, compared with the control. Besides, the protein and fat contents of the insect biomass were raised by 18.81 % and 20.97 %, respectively. The results also demonstrate that a trace amount of exogenous enzymes (amylase and catalase) and capsaicin were effective to accelerate food waste degradation, particularly for the higher growth of the black soldier fly (Hermetia illucens L.). As such, the quality of the black soldier fly (Hermetia illucens L.) biomass was improved to serve as the high-protein and high-fat feed. In the field experiment thereafter, the fresh biomass of the insect was fed, such as chickens. The dry biomass was used as an ingredient of feed for the fish to replace the plant protein, and the meal was liked by fish species in the aquaculture tanks. Anyway, the finding can guide the conversion of rice food waste to high-protein animal feed, particularly for the reuse and reduction of food waste. [ABSTRACT FROM AUTHOR]

Sesame seeds is recognized as a good source of lipids and proteins, and its processing is mainly focused on oil production. Sesame is rich in a variety of essential amino acids for human body, which has great development and utilization value. However, the processing of sesame proteins is limited by its poor solubility. Due to the sustainability, economical costs and health benefits of plant proteins, researchers have greatly increased their interest in them. At present, aqueous extraction processing has the capability to realize the comprehensive utilizations of lipids and proteins in sesame. However, the cost of commercial proteases is considerable for large scale applications. Previous studies in our laboratory have confirmed that endogenous proteases in sesame seeds have high activity, and it has great potential for aqueous extraction processing of sesame. While preparing lipid products, endogenous proteases could be used to biologically convert sesame proteins into hydrolysate with high solubility and nutritional function. In addition, in the previous study, the effects of pH value, temperature, and time on proteolytic activity of endogenous proteases in sesame milk were studied, and the proteins were optimally hydrolyzed at pH 4.5 value and 50 ℃ for 6 h catalyzed by the endogenous proteases. In this paper, wet-peeled sesame was dried and pressed in order to obtain the sesame oil and pressed meal. Then, the pressed meal was then hydrolyzed into hydrolysate by endogenous proteases. And the effects of drying temperature on pressed oil yield and proteolytic activity of endogenous proteases in wet-peeled sesame were investigated, which provides reference for the practical applications of endogenous proteases. The results showed that under hydraulic pressing (80 MPa, 1 h), the oil yield of sesame and peeled sesame (50 ℃, 4 h) (the total lipids in sesame as 100%) were 81.76% and 83.57% respectively, indicating that peeling is conducive to the improvement of oil yield. The oil yield of wet-peeled sesame increased to 88.55%-90.98% after drying at 80-180 ℃ for 1 h. For the endogenous proteases, its activity decreased slowly at 80-130 ℃ and remained about 57% at 130 ℃, indicating that endogenous proteases had good thermal stability, then the activity decreased rapidly after 130 ℃ and inactivated at 180 ℃. In order to modify proteins in the pressed meal with endogenous proteases, sesame seeds were dried at 50 ℃ for 4 h to obtain sesame oil and low-denatured pressed meal. After grinding, the sesame milk prepared from pressed meal was incubated at pH 4.5 value and 50 ℃ for 6 h. And hydrolyzed sesame milk was separated into two fractions (skim and precipitation) by centrifugation (3 000 g, 5 min). The results showed that the proteins in the skim still accounted for 66% of total proteins in sesame milk after centrifugation, and the proteins in skim were composed of 38% small peptides (< 1 500 Da) and 37% free amino acids. In addition, there are many bioactive substances in the skim, such as ornithine, serotonin, DL-dopa and so on. The purposes of this study were to evaluate the thermal stability of endogenous proteases in sesame seeds and to develop a new method for production of sesame protein hydrolysate, which enhanced the solubility and bioactive properties of sesame proteins. [ABSTRACT FROM AUTHOR]

Winter wheat (Triticum aestivum L.) is one of the major food crops in the world. Climate warming has dominated the growth and yield of winter wheat, particularly the protein formation and content of grains. But, the effects of warming on the protein content still remain unclear so far. Taking “Ji Mai 22” as the test material, this study aims to determine the specific effects of climate warming on the winter wheat growth and development, yield, and grain protein content. Climate warming was also simulated with an infrared warming device. Field warming experiments were conducted under the No Tillage (NT), and Conventional Tillage (CT) in the North China Plain for three consecutive years (2017-2019). The results showed that the open field warming reduced the overwintering period, indicating a significant shift in the regreening period. The nutritional growth period was then prolonged for the nitrogen accumulation time in the pre-anthesis period of plants. There was an increase in the Leaf Area Index (LAI) at the regreening-anthesis period, the net photosynthetic rate at the regreening-maturity period, and the aboveground dry mass of winter wheat. 20.17% (CT) and 99.21% (NT) of nitrogen accumulation in the winter wheat stems and leaves at the anthesis period, respectively, whereas, 24.62% (CT) and 134.21% (NT) of nitrogen transfer in the stems and leaves after anthesis increased by the warming in 2019, and the contribution of nitrogen in the stems and leaves contribution to seeds increased by 2.43% (CT), and 46.10% (NT). The NT warming increased the yield, where the NT yield was on average lower than that of CT. The CT yield of warmed winter wheat decreased by 2.14% and 4.62% in 2017 and 2018, respectively, and increased by 7.05% in 2019, whereas, the NT yield increased by 5.54% (2017), 34.44% (2018), and 42.25% (2019), respectively. The winter wheat yield in 2018 was significantly lower than that in 2017 and 2019. The reason was that the excessive precipitation in spring inhibited the winter wheat growth and development, leading to less yield in 2018. The temperature greatly contributed to the protein content of winter wheat grains, with an average increase of 14.28% (CT) and 17.39% (NT) for three consecutive years, compared with the control group. Therefore, the temperature promoted the conversion of nitrogen to the grain via the physiological characteristics of winter wheat. The reduction in effective spikelets number allowed the nitrogen for more grains to enter the final effective grain number, thus significantly increasing the grain protein content at high temperatures. The soil temperature under the NT was lower than that under the CT. The soil temperature was slower to rise in early spring, which affected the greening and early growth of wheat, resulting in the lower initial values of LAI, and net photosynthetic rate of winter wheat under the NT. The NT under the warming treatment reduced the post-anthesis soil temperature, but increased the soil water content, indicating the better wheat growth under a high post-anthesis temperature environment, compared with the CT. There was no significant difference in the grain protein content between CT and NT. This finding can provide a strong reference for the effect of climate warming on the protein content of winter wheat seeds under conservation tillage. [ABSTRACT FROM AUTHOR]

Tricholoma matsutake (TMWEIF) Singer is one of the most valuable mushrooms, particularly famous for its delicacy in the world. An excellent source of nutrients can be rich in proteins, unsaturated fatty acids, vitamins, dietary fibers, but low in fat. TMWEIF also shares the outstanding properties of anti-tumor, lowering cholesterol, antioxidant, and strengthening the immune system. High-temperature water extraction has been usually applied to extract the immunity active compounds at present. However, these immunity active compounds indeed are prone to be destroyed by high temperatures. In this study, the low-temperature (≤30 °C) water extraction of immunity active factors was performed on the TMWEIF from Changbai Mountain, China, using the response surface method (RSM) under the Box-Behnken center combination design by the Design Expert 10.0 software. The structure and amino acid compositions of the TMWEIF were further characterized by an automatic amino acid analyzer, Fourier transform infrared spectroscopy (FT-IR), circular dichroism spectrum (CD), and ultraviolet spectrum (UV). A single factor experiment were conducted at the liquid-solid ratios (10:1, 20:1, 30:1, 40:1, and 50:1 mL/g), extraction time (30, 60, 90, 120, and 150 min), and extraction temperature (10, 15, 20, 25, and 30 °C). An optimum extract condition was determined for the TMWEIF by RSM, where the NO emission by RAW264.7 macrophages, and the protein yield of extract were taken as the indicators. The results showed that the optimal extraction parameters for the protein yield were the liquid-solid ratio of 45:1 mL/g, extraction time of 140 min, and extraction temperature of 20 °C, where the extract was named TMWEIF-1. Moreover, the optimal extraction parameters for the NO release amount were the liquid-solid ratio of 30:1 mL/g, extraction time of 120 min, and extraction temperature of 20 °C, where the extract was named TMWEIF-2. The extraction parameters for the TMWEIF-2 presented a lower liquid-solid ratio and shorter extraction time than before, indicating an improved production efficiency. The protein yield and NO release amount were 8.07%, 3.68 μg/mL, and 7.06%, 4.11 μg/mL, respectively, for the TMWEIF-1 and TMWEIF-2 under the optimal conditions. There were significant differences (P<0.05) between the TMWEIF-1 and TMWEIF-2 in the protein yield and NO release amount. The measurements were well matched with the predicated values from the models, indicating that the regression equations and models were reliable to predict the influences of factors on the protein yield and NO release amount of the extract. The FT-IR analysis showed that the TMWEIF-1 and TMWEIF-2 exhibited the typical absorption peaks of protein and polysaccharide within the wave number of 4000-500 cm-1. The FT-IR and UV analysis showed that the structures of TMWEIF-1 and TMWEIF-2 were similar, and the main components were protein and polysaccharide. The CD analysis revealed that the secondary structures of protein in the TMWEIF-1 and TMWEIF-2 were mainly α-helix and β-turn, where the higher content of α-helix was observed in the TMWEIF-1, and a larger amount of β-turn in the TMWEIF-2. The polysaccharide contents in the TMWEIF-1 and TMWEIF-2 were 306.95 and 304.98 mg/g, respectively, and the protein contents were 132.14 and 107.78 mg/g, respectively. The polysaccharide was also mainly glucan with α-glucoside, according to the content determination. The amino acids analysis showed that there was no significant difference (P>0.05) in the contents of amino acids in the TMWEIF-1 and TMWEIF-2, where the essential amino acids accounted for 27 %. Both TMWEIF-1 and TMWEIF-2 contained 17 kinds of amino acids rich in glutamate (Glu) and aspartic acid (Asp), but the relative content of Glu of TMWEIF-2 was slightly higher. Besides, there was a higher mean percentage of hydrophobic amino acids and basic amino acids related to the immune activity in the TMWEIF-2 than that in the TMWEIF-1. Consistently, the NO release induced by the TMWEIF-2 was significantly higher than that by the TMWEIF-1. Consequently, the TMWEIF-2 and the extraction parameters are expected to serve as the better industrial application prospect, in terms of extraction efficiency and immune activity. The finding can provide a scientific basis for the further development and utilization of immunity active factors in the wild matsutake functional foods. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of oat antifreeze protein on the non-fermented dough during freezing, together with the quality changes during the processing of the dumpling wrapper. The 0.5% oat antifreeze proteins were added to the dumpling wrapper. A systematic evaluation was then made on the oat (Avena sativa L.) Antifreeze Proteins (AsAFPs) in the frozen dumpling wrapper during freezing and storage. Some parameters were also measured to clarify the regulatory mechanism, including the moisture content, freezable water content, color, texture, rheological properties, the free sulfhydryl group, disulfide bond content, and secondary structure of hydrated gluten at different freezing periods. The results showed that the moisture content of the dumpling wrapper significantly decreased from 33.22% to 29.34% (from 34.98% to 26.57% in the control group) after 28 d freezing and storage, indicating that the addition of AsAFPs could greatly contribute to slowing down the moisture loss. The freezable water content of the dumpling wrapper after AsAFPs addition was lower than that in the control group (P<0.05). As such, much fewer ice crystals were beneficial to alleviate the mechanical damage to the network structure during freezing. The brightness of the dumpling wrapper was only slightly reduced after AsAFPs addition, which was related to the color of AsAFPs. More importantly, the dumpling wrapper in the AsAFPs group shared the better textural properties, lower hardness, gumminess and higher springing, cohesiveness, chewiness, and resilience (P<0.05). The elastic and viscous modulus of dumpling wrapper in the AsAFPs group was much higher than that of the control group (P<0.05). The change was attributed to the weak gluten cross-linking effect after AsAFPs addition. The sulfhydryl content of the AsAFPs group was lower than that of the control group (P<0.05), while the disulfide bond content was higher than that of the control group (P<0.05). It infers that the addition of AsAFPs could greatly contribute to inhibiting the breakage of the disulfide bond. There was a slightly decreasing trend in the α-helix and random-coil of hydrated gluten of dumpling wrapper, whereas, an overall increasing trend in the β-sheets and β-turns. Nevertheless, the AsAFPs was used to inhibit the breakage of hydrogen bonds and other stable groups, leading to the smaller decrease of random-coil and α-helix (P<0.05). The finding can provide a strong reference for the application and quality improvement of antifreeze proteins in non-fermented doughs. [ABSTRACT FROM AUTHOR]

A rapeseed has been the second largest oil crop in the world, especially in Canada and China. The main by-products after oil extraction, rapeseed meals have been normally used for animal feed or agricultural fertilizer. However, a low economic benefit has resulted from rapeseed meals with plenty of proteins. Among them, the protein from the rapeseed cold-pressed cake can be used to develop high value-added products, due to the light color and low degree of denaturation. The rapeseed protein also showed better nutrition for the body health of humans, due to the nutritionally balanced amino acid composition and high S-containing amino acid. Conventionally, the alkali-solution and acid-isolation extraction are widely used for protein extraction, where a strong alkali or acid can be selected to adjust the pH, but the water quality can deteriorate. Fortunately, the alkaline electrolyzed water (a by-product of acid electrolyzed water) has been served as an excellent solvent, because of the high reducing power, small molecule cluster structure, low surface tension, and strong permeability. Moreover, it is easy to gradually return to the normal water after use. In this present study, an electrolyzed water extraction of protein was optimized for the cold-pressed cake of double-low rapeseed in a highly efficient and environmentally friendly way. A one-factor Box-Behnken test was also designed to measure the extraction rate, structural and functional properties of rapeseed protein, further to compare with the conventional alkali dissolution and acid precipitation. The results showed that there was the most influential of pH values on the extraction rate, followed by the extraction temperature, solid-to-liquid ratio, and extraction time. An optimal combination of parameters was also achieved, where the extraction temperature was 45 ℃, the pH value of alkaline electrolyzed water was 11.5, the solid-to-liquid ratio was 1:10 (g/mL), the extraction time was 60min, and the extraction rate of rapeseed protein was 59.34%. An excellent extraction performance of alkaline electrolyzed water was obtained with the increasing extraction rate from 50.72% to 59.34% (P<0.05), the improved solubility (from 30.62% to 38.40%, P<0.05), and the high absolute value of zeta potential (from 10.17 mV to 11.90 mV, P<0.05), compared with the alkali-dissolved acid precipitation (using the ultrapure water extracted rapeseed protein, URP). Likewise, the numberr of sulfhydryl groups and free sulfhydryl groups increased from 20.43 to 22.64 μmol/g (P<0.05), and 15.00 to 16.88 μmol/g, (P<0.05), respectively, compared with the URP. The Fourier transform infrared spectrum showed that the random coil and β-turn decreased significantly, whereas, the β-sheet increased, compared with the URP. The surface tension at the air-water interface was reduced, because the surface hydrophobicity increased from 40.70 to 50.92 μg (P<0.05), where the particle size was reduced, but the fluorescence intensity increased significantly. Furthermore, the emulsifying activity, foaming capacity, and fat absorption activity increased from 32.92 m²/g to 35.13 m²/g (P<0.05), 47.17% to 52.92% (P<0.05), and 1.86 to 2.41 g/g (P<0.05), respectively. Therefore, the extraction of rapeseed protein from the cold-pressed cake with the alkaline electrolyzed water can be widely expected to improve the extraction rate, further reducing the usage of strong alkali reagent. This finding can also provide a new strategy to extract the rapeseed protein for less impact on the structure and the better functioning of rapeseed protein. [ABSTRACT FROM AUTHOR]

The purpose of this study is to explore the nutritional components and physicochemical properties in five types of protein raw materials and their mixed powder, including soybean meal, cottonseed meal, rapeseed meal, distillers dried grains with solubles (DDGS), and Clostridium Autoethanogenum protein (CAP). Key indicators were determined on the processing quality of pellet feed and energy consumption of granulation. A comprehensive evaluation was also performed on the granulation of protein raw materials. Five kinds of protein raw materials were mixed with ground corn at the weight ratio of 3:7 in a single-factor experimental design. The soybean meal was taken as the control group, whereas, the pelletized feed was prepared with the same processing parameters. Correlation analysis and partial least squares regression (PLS) were conducted to compare the pelletizing quality of different protein raw materials. The results showed that there were significant differences in nutritional components and physicochemical properties of raw materials, where the CAP presented a high protein content and solubility while low fat and fiber, the cottonseed meal with high fiber, the rapeseed meal with high fiber and low protein solubility, as well as the DDGS with low protein and high fat. Water absorption of protein raw materials was ranked in descending order: CAP, soybean meal, cottonseed meal, rapeseed meal, and DDGS. The energy consumption of CAP group and cottonseed meal group was higher than other group, and soybean meal group was lowest; the higher Modified Pellet Durability Index (MPDI) of the cotton meal group and CAP group was 92.72% and 90.57% respectively, and the lowest MPDI of rapeseed group was 79.7%. The highest hardness of CAP group was 130.95 N, and the lowest hardness was 74.26 N in DDGS group. The highest gelatinization degree of CAP group was 45.56% and the lowest of gelatinization degree was 31.36% in DDGS group. The partial least squares regression model demonstrated that the protein content and solubility, as well as the water absorption significantly improved the hardness, PDI, and MPDI of pellet feed. The crude fiber content, protein solubility, and water absorption contributed tosaving the energy consumption of pelletizing. The granulation characteristics were ranked in the order from high to low: CAP, cottonseed meal, soybean meal, rapeseed meal, and DDGS. The findings can provide a sound reference for the selection of protein raw materials in the actual production of pellet feed. [ABSTRACT FROM AUTHOR]

Soy protein isolate has a reasonable protein composition ratio- It is not only cholesterol-free but also contains essential fatty acids, phospholipids, and rich minerals such as calcium and phosphorus. Cavitation jet is a new technology that can produce cavitation phenomenon. This technology can change the structure of pea globulin aggregates and enhance its emulsion stability. It can also significantly affect the tertiary structure of β-lactoglobulin and the structure and functional properties of soy 11S globulin. In order to explore the effect of cavitation jet treatment on the structure and emulsification characteristics of soy protein isolate, soy protein isolate solutions of different concentrations (2% and 5%) were treated with cavitation jets at different times (2, 4, 6, 8, 10 min), and the untreated soy protein isolate solution was used as a control to explore the effect of cavitation jet treatment on the structure and emulsification properties of soy protein isolate in this study. The results showed that the cavitation jet treatment for an appropriate time could reduce the sulfur-containing amino acid content, the average particle size of the solution, and the 7S subunit and A subunit content of the soy protein isolate and caused the absolute value of the ζ-potential of the protein emulsion and the increase of the interface protein content. The high and elastic modulus tended to increase, thereby significantly enchancing the protein emulsification activity and emulsification stability. The emulsification activity and emulsification stability reached the maximum value of 71.01 m²/g and 168.75 min when the 2% concentration SPI was treated by the cavitation jet for 8 min, which were 248.94% and 95.58% higher than the minimum value. At the same time, the absolute value of the zeta potential reached the maximum value of −14.11 mV, the interface protein content reached the maximum value of 3.19 mg/m², and the particle size was the smallest (590.5 nm). When the cavitation jet was treated with 5% concentration SPI for 10 min, the emulsification activity and emulsification stability reached the maximum, which were 52.91 m²/g and 126.97 min, respectively, 70.29% and 101.83% higher than the minimum. However, the absolute value of ζ-potential and the interface protein content had shown a downward trend. It showed that although the emulsification performance of soy protein isolate was still at a good level, it had already been processed. It could be seen that the cavitation jet treatment of two concentrations of soy protein isolate could depolymerize part of the subunits and reduce the content of sulfur-containing amino acids. At the same time, the cavitation effect expanded the protein molecules, exposed more hydrophobic amino acids, and improved its rheological properties. When the SPI concentration was 5%, all indicators were easier to reach the extreme value than when the SPI concentration is 2%. This showed that the cavitation jet physical field could adjust the emulsification activity of soy protein isolate by changing the structure and emulsion interface characteristics, which had important scientific significance for the development of new soy protein beverages, protein biogels, etc., and it was also a modification of soy protein isolate. And the application of cavitation jet physics in the food field provides the preliminary foundation. [ABSTRACT FROM AUTHOR]

An in-line detection system of grain protein content was developed in this study, in order to realize the real-time identification and record the sampling geographical location information in a novel harvester combined with near-infrared spectroscopy during grain harvesting. The detection system was mainly composed of a near-infrared spectral sensor module, spiral sampling and conveying mechanism, control module, GPS/Beidou positioning module, and industrial display integrator. The specific working procedure was followed for the in-line detection system in a near-infrared spectroscopy on combine harvester. The grain first discharged from the outlet of a combine-harvester through the spiral sampling and conveying mechanism. A PID controller was used to adjust the stepper motor of sampling mechanism, according to the requirements of detection rate, thereby to realize the intermittent grain transmission. A near-infrared spectral sensor was also adjusted to capture the spectrum, when the stepper motor stopped turning. A RS485 bus was used for data transmission to host computer, where the obtained data included the grain near-infrared spectrum, and the positioning signal of GPS/Beidou positioning module. A data processing software was developed to control the near-infrared sensor and sampling mechanism. After data post-processing in the grain protein prediction model, the information of grain protein and sampling location was in situ displayed, and storage for later use. An indoor calibration, and a field dynamic test were carried out to verify the performance of prediction model for grain protein content and online detection system. In the prediction model of wheat protein content, the decision coefficient was 0.865, the absolute error range was −0.96 to 1.22, the relative error range was −7.30% to 9.53%, and the root mean square error of prediction (RMSEP) was 0.638. In the prediction model of rice protein content, the decision coefficient was 0.853, the absolute error range was −0.60 to 1.00, the relative error range was −8.47% to 9.71%, and the RMSEP was 0.516. In the dynamic field test, the maximum relative error of wheat protein content was −6.69%, whereas, the maximum error of rice protein content was −8.02%. It infers that the sampling and analysis interval have no significantly influence on the detection system, where the system stability and detection accuracy meet the need of grain protein online detection in the field. The finding can provide a scientific basis for precision agricultural operation. [ABSTRACT FROM AUTHOR]

Rice bran is the main by-product of the rice milling process with high protein content. Although there is a large amount of rice bran in China, most of it is used to raise animals. Therefore, for the economic benefits of the rice processing industry, it is inevitable to fully develop the added value of rice bran. Longjing No.31 rice bran was chosen as the protein source in order to study the effect of extrusion stabilization treatment on the protein structure and functional properties of each component of rice bran,, and effects of rice bran extrusion stabilization using twin-screw extruder on structural and functional properties of rice bran protein fractions were also investigated. The results showed that the solubility, foamability and oil-holding capacity of each component protein of rice bran were significantly reduced after extrusion treatment (P<0.05), this is because insoluble aggregates are formed after high temperature, high pressure and high shear. The water-holding capacity, foaming stability and emulsion stability were increased, among which the water holding capacity of gluten increased the most, 39% higher than that before extrusion. After extrusion, the structure of gluten changed, forming more random coil structures, and the unfolded protein molecules interacted with each other to form a more stable network structure, thereby increasing the foaming stability of gluten. As well as, its emulsifying activity was significantly different from that of other protein fractions. On the other hand, the albumin and globulin contents decreased by about 5% and 10%, while gluten increased by about 8% after extrusion, respectively. The emulsifying ability of rice bran protein was related to factors such as solubility, and the thermal denaturation caused by stabilization reduced the emulsifying ability of each component of rice bran. Structural analysis indicated that changes in protein fractions after extrusion mainly attributed to a recombination among them, which indicated by differences in the secondary structure. The α-helix, β-turn, and random coil contents of the albumin decreased significantly after extrusion, while the content of β-sheet folding increased significantly. Moreover, the rice bran gluten showed a different trend from that of albumin, and the secondary structure of gluten changed significantly in the amide I zone, the content of α-helix, β-turn and random coil increased, and the content of β-sheet decreased. After high temperature and high pressure treatment, the hydrogen bond of the protein was broken, so the protein was partially denatured and its structure was also changed. The results can help in understanding changes occur in structural and functional properties of rice bran protein fractions during extrusion to promote the utilization of rice bran protein in the food industry. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the changes of water state, proportion and structure during dough mixing and resting in order to establish a relationship between those changes and dough quality properties during dough mixing and resting using Farinograph and Extensograph, which helps to understand the dough development mechanism for flour with different gluten strength. Two wheat varieties (Ningchun4 and Shiluan02-1) with different gluten strength were selected as experimental materials. Water state (T2) and relative proportion (A2) in dough were investigated at different time during dough mixing, and dough resting and stretching by Low-Field Nuclear Magnetic Resonance (LF-NMR). Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance micro (FTIR-ATR) was used to analyze the distribution of starch and protein and the structural changes of protein at different sampling points during the dough mixing. The results showed that water in raw flour were mainly less tightly bound water (T22). While flour was mixed with water in Farinograph to dough development time, three types of water, tightly bound water (T21), less tightly bound water (T22) and free water (T23) were found in the dough. With longer mixing time, the relative proportion of tightly bound water (A21) in Yongliang 4 significantly decreased; transverse relaxation time of tightly bound water (T21) in Shiluan 02-1 did not show by the end of the mixing, transverse relaxation time of less tightly bound water (T22) was significantly prolonged, while the relative proportion of free water (A23) was significantly increased (P<0.05). Water states and proportion for dough mixed with salt or without salt showed no significant changes during dough resting and stretching (P<0.05). After resting, the transverse relaxation time of free water (T23) in Yongliang4 was significantly shortened (P<0.05). The network of dough with higher gluten content was more compact in dough structure. The changes of the relaxation time and proportion of tightly bound water and less tightly bound water during mixing were related to the gluten content and strength. During dough mixing, the relaxation time of strongly bound water (T21), extended or disappeared by the end of mixing. The relative proportion of free water (A23) increased significantly. Strong gluten wheat flour had a longer retention time of strongly bound water. The changes of relaxation time and ratio of strongly bound water and weakly bound water were related to the gluten content and strength. The essences of flour quality characterized by Farinograph were the change of gluten network structure and the tolerance degree of kneading during dough mixing. The changes of water binding state and proportion during dough formation could be effectively characterized by LF-NMR technology. The results can provide some theoretical basis for the selection and optimization of mixing processing. [ABSTRACT FROM AUTHOR]

In the process of dough blending, the water addition and mixing time have important influences on the sensory quality, physical and chemical properties, and texture of food products. The optimum amount of water addition can significantly improve the structure and quality of flour food. If the water addition is too high, the dough will be too soft and difficult to form. If the water addition is too low, the protein in the gluten cannot fully contact with the water, and thereby to form relatively low gluten. Alternatively, if the mixing time is insufficient, the internal structure of dough sheets will be rough and uneven with many particles, where the surface of dough sheets can be easy to tear. If the mixing time is too long, the surface of dough sheets will be too wet and sticky, unfavorable to the shaping operation of dough sheets. The moisture content of dough is also closely related to the properties of flour protein after dough formation. Taking wheat dough sheets as the research objects, the effects of water addition on the texture and protein properties of dough sheets under different mixing time were invesigated. Texture analyzer was selected to characterize the sensory physical property and texture characteristics of dough sheets, particularly related to mechanical properties. Fourier transform infrared spectroscopy (FTIR) was used to collect the infrared absorption spectrum and radiation spectrum of dough sheets. The protein content in the dough sheets was obtained using the Gauss deconvolution and second-order derivative methods. High performance liquid chromatography (HPLC) was used to determine protein content. The results showed that the tensile force and hardness of dough sheets decreased, while the extensibility and viscosity increased with the increase of water addition. In moderate water addition, the water molecules could be fully immersed in gluten protein to generate the protein hydrate, and thereby to form a gluten network with mutual adhesion,indicating good extensibility, high viscosity, strong tensile resistance, and low hardness. In low water addition, the flour cannot fully absorb water, the gluten protein cannot fully hydrate, and thereby the formation of dough sheets was rough and hard, with the strong instant breaking force. In high water addition, the starch in flour dissociated from the gluten network, while the gluten protein and starch were in the state of water absorption saturation, where too many water molecules existed between protein-protein and protein-starch particles to weaken the intermolecular force, thereby to reduce the viscosity, toughness, and the tensile strength of dough sheets, leading to extremely low hardness and pull deformation. The water addition can significantly increase the whiteness (L *) and red green value (a *) in the color of dough sheets. The yellow blue value (b *) reached the maximum at the water addition of 45%, due to the light refraction and the action of polyphenol oxidase, indicating the strongest browning of dough sheets. The b* value of dough sheets decreased when the water addition reached 50%, where the browning slowed down due to the dilution of polyphenol oxidase. The content of sulfhydryl group, secondary structure and large molecular weight polymer protein in gluten protein were also affected by the amount of water added to gluten. The content of sulfhydryl group reached the minimum at the water addition of 40%, as well the lowest occurred in the content of large molecular weight polymer protein formed by disulfide bond. The reason was that water can promote the formation of hydrogen bond, and then maintain the content of β- sheet and α-helix, further to stabilize the conformation of protein. There was complex influence of mixing time on the texture and protein properties of dough sheets. The extensibility of the dough sheets was the better, the tensile force, hardness were moderate, viscosity and sulfhydryl content were the lowest, and the content of β- sheet was higher at mixing time of 15 min. In the mixing time of 15 min and the water addition of 40%, the dough sheets achieved the optimum, particularly on the formation of chemical bond and the transformation of stable secondary structure. When the mixing time was not enough, the weak hydrogen bond between protein molecules cannot extend the gluten network, and thereby to increase the content of random coil of disordered structure. When the mixing time was too long, the formed hydrogen bond broke again to destroy the molecular structure of protein, where β-sheet was converted into β–turn. The findings demonstrated that the optimum water addition and mixing time can improve the texture characteristics of dough sheets and the cross-linking of gluten protein. The application of appropriate water addition and mixing time in production can provide reference for the production parameters of flour products. [ABSTRACT FROM AUTHOR]

Air-dried yak meat can be produced by a traditional procedure, where the raw yak meat is divided into strips, then naturally air-drying (about 40 days) under a low temperature condition. This ancient processing is still popular in China at present, particularly on the high altitudes areas (generally over 3 000 m), probably due to the influence of traditional eating habits and inheritance of culture. High-protein yak meat can be used to enhance the resistance of cold climates in these areas. However, the protein digestibility of air-dried yak meat has not been evaluated during traditional processing. Consequently, the objective of this study was to evaluate the changes in digestibility of myofibrillar protein during the processing of traditional air-dried yak meat, and further to investigate the underlying effect of protein oxidation on protein digestion. Taking the healthy 3 to 4-year-old male yaks as subject, the semimembranosus was selected to remove the fascia and fat on the surface, and then cut into a cross-section of 2×2 cm2 strip in Gannan prefecture of Gansu province. The meat was hung on the wire, and kept the distance of 1 to 2 cm between two adjacent pieces of meat in a dark ventilated naturally place in Xiahe County, Gannan Prefecture, Gansu Province. The temperature was set as 10 to 15 ℃, and the relative humidity was 50% to 75%. During air drying, changes were monitored in lipid oxidation, protein oxidation, protein particle distribution, and in vitro digestibility, in order to explore the effects of lipid and protein oxidation on protein digestibility. Samples were collected to analyze during natural air-drying for 40 days. A model was introduced to simulate the digestion of proteins in the stomach and duodenum, specifically to investigate the nutritional change of the air-dried yak meat in the processing. The results showed that the lipid Primary Oxidation Value (POV), Thiobarbituric Acid Reaction Substrate (TBARS) and protein carbonyl compounds increased dramatically with the extension of processing time (P<0.05), and there was a significant correlation between them (P<0.01). In addition, the content of disulfide bonds and dimeric tyrosine increased significantly (P<0.05), which is the main form of protein cross-linking. The digestibility of protein decreased by 19.58% during the whole process (P<0.05). The hydrolysis rate of protein by protease showed a significant correlation with the carbonyl group, disulfide bond, dimeric tyrosine, and protein particle size (P<0.01). Lipid oxidize products can promote protein oxidation, while the carbonylation and cross-linking of proteins can cause a decrease in protein hydrolysis rate by proteases. This study has a positive role to understand the traditional processing of air-dried yak meat, and further to improve processing technology and quality of yak meat. [ABSTRACT FROM AUTHOR]

Compared with conventional Japonica rice, the grain yield of Indica-Japonica hybrid rice in pot-seedling transplanting is more advantageous. However, there are few studies on its quality effect under high nitrogen application rate. A field experiment was performed to investigate the effects of five fertilizer-N application rates (0, 195, 255, 315, 375 kg/hm² represented by N0, N195, N255, N315, N375) on grain yield, rice quality, agronomic traits and economic benefit of Yongyou1540 (Indica-Japonica hybrid rice) and Zhendao18 (conventional Japonica rice), which are local main cultivars, in 2016 and 2017. Due to increase in leaf area index and net photosynthetic rate after the panicle initiation, dry matter accumulation, increase in the number of spikelets per panicle, the filled grain rate and thousand-grain weight were ensured, the grain yield of Yongyou1540 under N315 was the highest at 11.55 t/hm² (2016) and 10.30 t/hm² (2017). No significant difference was found for rice yield of conventional japonica rice Zhendao18 among different nitrogen application rates, with grain yield of 8.49-8.91 t/hm2 and 7.43-7.91 t/hm² in 2016 and 2017. When the nitrogen application rate was less than 315 kg/hm², the dry matter accumulation at the maturity stage and leaf area index at the heading stage of Yongyou1540 increased with the increase of nitrogen application rate. When the nitrogen application rate exceeded 315 kg/hm², it continued to increase and even had a downward trend. Increased application of nitrogen fertilizer improved the milling quality by increasing the brown rice rate, milled rice rate, and improved nutritional quality by increasing the protein content of the two varieties. However, the chalkiness and chalkiness degree increased and the amylose content decreased. The head rice rate of Yonyou1540 under N315 was 74.17% and 69.97% in 2016 and 2017, and they were not significantly different from N375. The chalkiness (11.00%, 17.33%) under N315 had no significant difference with N195. In addition, the percentage of head rice, protein content, chalkiness and amylose content of Zhendao18 under N195 was not significantly different from the other nitrogen fertilizer treatments. As the amount of nitrogen applied increased, the net income of Yongyou 1540 showed a trend of increasing and then decreasing, and N315 was the largest (15 513.3 and 12 263.3 Yuan/hm2 in 2016 and 2017). However, the income-increasing benefit of Zhendao 18 was not obvious due to increasing application of nitrogen fertilizer. The amount of nitrogen fertilizer with high-yield and premium-quality of Indica-Japonica hybrid rice in pot-seedling transplanting was 315 kg/hm², and that of conventional Japonica rice was 195 kg/hm² . Compared to Zhendao18, Yongyou1540 in pot-seedling transplanting under suitable nitrogen levels improved grain yield by 22.9%-23.2%, increased head rice rate by 2.15%-4.50%, increased protein content by 30.44%-37.41%, and increased economic benefits by 51.07%-53.33% while reduced chalkiness by 9.52%-13.73%. In general, it is conducive to improving rice yield, quality and economic benefits for selecting Indica-Japonica hybrid rice in pot-seedling transplanting under 315 kg/hm2 nitrogen fertilizer along the Yangtze River area in Anhui Province. [ABSTRACT FROM AUTHOR]

Food allergy has become a major public health and food safety issue concerned by the world . In the world, 0.2% -0.9% of adults and 0.4%-1.3% of children suffer from wheat allergy, which seriously affects the lives of allergic patients. The structure of food allergens can be changed by processing, which maight affect their allergenicities. Therefore, it is meaningful to study the influence of different processing on the allergenicity of gliadin in non-fermented dough. Here non-fermented dough were treated by different processing such as thermal processing (boiled, baked, microwave, high temperature and high pressure), cold treatments (liquid nitrogen, quick freezing machine) and non-thermal processing (static ultrahigh pressure, irradiation, pulsed light, ozone and ultrasonic). The molecular weight and the allergenity of wheat gliadin in non-fermented dough after various processing were determined by SDS-PAGE and the double antibody sandwich ELISA. SDS-PAGE electrophoresis results showed that the molecular weight of wheat gliadin in non-fermented dough changed significantly after boiled, baked or high temperature and high pressure treatment. The results of Sandwich ELISA showed that when the holding pressure temperature was 35℃ and the holding time was 20 min, the non-fermented dough wheat gliadin was treated with 100 -300 MPa ultra-high static pressure, its allergenicity increased first, then decreased, and then increased again, of which its allergenicity significantly decreased to 80.94% when treated at 250 MPa, and significantly increased to 127.27% or 128.17% when treated at 200 or 300 MPa, respectively, indicating that ultra-high static pressure treatment has a allergenicity increasing effect of gliadin in non-fermented dough; Irradiation treatment with γ-60Co at a dose of 1-15 kGy resulted in the allergenicity of gliadin in non-fermented dough decreased first, then increased and then decreased again, at 7, 13 kGy, the allergenicity decreased to 72.32% or 84.03%, respectively; The allergenicity of non-fermented dough wheat gliadin was significantly reduced after these hot, cold and non-heat processing treatments (P<0.05). After 2 hours of 500-watt ultrasonic treatment, its allergenicity was reduced to 90.23%; after Microwave, Quick-freezer, Pulsed light, or Baked treatment, it was reduced to 85.36%, 79.49%, 79.08% or 76.69%, respectively. Among them, the most significant (P<0.01) reduction in allergy was observed after Boiled, High temperature and high pressure, Liquid nitrogen, Ozone and Pulsed light (PL-1) treatment, and all of which decreased to about 60%, and ranked following by Boiled> Ozone fumigation 30 min (O3-1)> Liquid nitrogen> Pulsed glare 1 (PL-1)> High temperature and high pressure> Ozone fumigation for 60 min (O3-2). In short, the processing modes can significantly affect the allergenicity of non-fermented dough wheat gliadin, which can be used as an effective method for the safety control of food allergens and provide an effective reference for the production of desensitized food. At the same time, people's daily diet can be healthier by choosing a suitable processing method, especially for wheat susceptible people. Of course, the influence of different processing methods on the decreasing allergenicity of non-fermented dough wheat gliadin need to be further validated in combination with other in vivo experiments and especially the clinical trials of wheat susceptible people. [ABSTRACT FROM AUTHOR]

The effect of cold smoking on fish physicochemical properties and the myosin conformations were studied in the Coregonus peled from Sayram Lake. The smoke box temperature and smoke temperature was set as (20±2) ℃and 140 ℃, respectively, and series of smoke duration was set as 0, 6, 12, 18, 24 h. The moisture content, water activity(Aw), color, texture, TVB-N of fish and the myosin content, total sulfhydryl content, Ca2+-ATPase activity and hydrophobicity of myosin were determined. The results showed that, after smoked for 24 h, the fish moisture content decreased from 75.75% to 53.03%, the Aw decreased from 0.988 to 0.952, the lightness (L*) decreased, the redness (a*) and yellowness (b*) increased significantly (P<0.05), and both the shear force and toughness were obviously increased (P<0.05). TVB-N increased gradually from 9.81 to 14.43 mg/100 g when smoking time was increased from 0 to 24 h. It was observed that myosin concentration, total sulfhydryl content, Ca2+-ATPase activity decreased, and surface hydrophobicity increased during smoking (P<0.05). It was found that the optimum cold smoking time was 12-18 h to keep the quality of smoked fish and reduce the degree of myosin degeneration and oxidation of fish meat. This paper provides theoretical basis and technical guidance for the development of cold smoked products and control of protein oxidation during smoking processing [ABSTRACT FROM AUTHOR]

The physicochemical properties, such as total sulfhydryl (T-SH) group, active sulfhydryl (R-SH) group, surface hydrophobicity and turbidity, were determined for the myosin that extracted separately from the raw materials, rinsed- and simmer surimi in sea bass, while the secondary structure and surface morphology of the myosin were analyzed using the combined techniques including the infrared spectroscopy and atomic force microscopy (AFM). The experimental results showed that the content of total sulfhydryl (T-SH) groups in the myosin of the rinsed surimi decreased by 19.5% from 8.51 to 6.85 mol/105 g, whereas the active sulfhydryl group increased by 63.9% from 1.39 to 3.86 mol/105 g, compared with the raw materials. The content of total sulfhydryl (T-SH) and active sulfhydryl (R-SH) groups in the myosin of the simmer surimi decreased to 5.3 and 1.28 mol/105 g compared with the raw materials, indicating decrease by 22.6% and 66.8%, respectively. The ratio of the active sulfhydryl (R-SH) to the total sulfhydryl (T-SH) group in the myosin of the rinsed surimi is the largest than others, inferring that the myosin of the rinsed surimi can be the most deformed in this case. The turbidity and surface hydrophobicity, the indictor for the aggregation and degree of denaturation in proteins, in the myosin of the surimi increased after the treatment of rinsing and simmering. Specifically, the turbidity of the myosin in the surimi increased by 12.5% after rinsing and 22.2% after simmering, compared with raw materials, whereas the surface hydrophobicity increased by 47.9% after rinsing and 5% after simmering. The data reveal that the treatment of the rinsing and simmering can significantly affect the denaturation and aggregation of proteins in the varying level. The rinsing has a greater influence on the surface hydrophobicity, while the mixing effect has a greater influence on the turbidity. The simmering can cause the slight aggregation of the myosin to form a sort of microgel. There was a much more obvious effect of the rinsing on the secondary structure of the myosin. In Fourier transform of the infrared spectroscopy the α-helix relative content of the myosin that extracted can decreased by 33.16%, while the random curl relative content increased by 79.42%, β-fold and β-turn increased by 1.11% and 10.38%, respectively, after the rinsing of raw materials in the sea bream. After rinsing, the change rate of the secondary structure in the surimi myosin was smaller, and the α-helix and random curl content decreased by 1.16% and 7.95%, β-fold and β-turn increased by 4.16% and 1.92%, respectively. Generally, the decrease in the α-helix content can be conducive to the aggregation of proteins, and the increase in β-sheet and β-turn can be beneficial to the formation of the good gel structure. The characterized results from atomic force microscopy (FAM) showed that the myelin myosin exhibited a sort of protein bundle under the natural conditions, and the distribution of the protein bundle in the suspension was uniform without obvious granularity. Both treatment of the rinsing and simmering can change the surface morphology of the myosin in the sea bass, indicating reduce significantly the aggregation clusters of the myosin, while increase the height of the aggregates in the myosin suspension from 14 nm to 25 nm. After mixing, the height of the myosin aggregates did not change significantly. These findings demonstrate that the treatment of the rinsing and simmering have a great influence on the physicochemical properties of the myosin in rinsed and simmer surimi of the sea bass, as well as a certain effect on the degeneration and aggregation of the myosin suspension. This study can be expected to provide potential reference for the future development on the formation mechanism of surimi gel in food industry. [ABSTRACT FROM AUTHOR]

Rapid and accurate estimation of crude protein (CP) content in pasture plays an important role in the monitoring and management of the forage growth on a wide range of grassland. Crude protein contents of pastures are ideal for characterization using hyperspectral data. In view of the limitation of ground and satellite remote sensing, in this paper, we attempted to achieve an accurate estimation of CP content in forage by unmanned aerial vehicle (UAV)-based hyperspectral remote sensing images with high spatial resolution of the pasture canopy. Although the hyperspectral data of the forage have a large number of bands, the reflectance of the canopy spectrum at each band contains information of various parameters which are from atomic level to plant community level. So, when estimating a physicochemical parameter using the spectral data, we may achieve low prediction accuracy because the spectra are affected by other parameters. Compared with the original spectra, multi-granularity spectral features can provide more sensitive features for inversion of chemical parameters. More importantly, multi-granularity spectral features can extract some hidden weak spectral information, which is of great significance for inversion of low-content physical and chemical indicators. However, in current inversion methods of pasture CP content, there is a lack of effective utilization of spectral multi-granularity information. In view of this, we first proposed a novel multi-granularity spectral feature extraction approach named multi-granularity spectral segmentation (MGSS) to segment each canopy spectrum into multiple spectral features. Second, by using the sequential forward selection method, sensitive components of each feature under a granularity can be selected. Finally, based on these selected components of different features, the inversion models of pasture CP content can be established using two regression methods, i.e., the stepwise multivariate linear regression (SMLR) and the partial least squares regression (PLSR). Taking a typical meadowland in Qinghai Plateau as an example, the detailed experimental analyses have been conducted. Results showed that under the same quantity sensitive components for MGSS and sensitive bands for the raw spectra, on the estimation accuracy of pasture CP content, MGSS was superior to the raw spectra. So the validity of MGSS in improving the accuracy of hyperspectral estimation of CP content in forage was verified. Specifically, under Granularity 23 (G23) of MGSS, the PLSR model achieved the best performance. Its determining coefficient (R²) was 0.937 which was 0.06 higher than that of the optimal model of the raw spectra. And the root mean square error (RMSE) and the mean relative error (MRE) were 1.906 (g/m²) and 8.82%, respectively, which were 0.75 (g/m²) and 1.37 percentage points lower than those of the optimal model of raw spectra. Moreover, on the single and combined components sensitive to CP content in forage, there were three characteristics among the selected components of MGSS, i.e., the agglomeration within the Red Edge range, the dispersion of non-Red Edge range, and the sparsity of strongly sensitive components, which can be helpful for selecting sensitive components. In conclusion, the proposed MGSS achieved the high performance estimation of CP content in forage by UAV hyperspectral imagery. And compared with the raw spectra, MGSS had better performance. This study provides a new technical means for the accurate estimation of CP content in grasslands in large areas. [ABSTRACT FROM AUTHOR]

Dry-cured ham processing generates huge amounts of byproducts including bones, meat trimmings and skins resulting from both trimming and deboning during the processing of meat products. This waste represents a high cost for the meat processing sector and a serious environmental problem. As a result, meat processing industries are making a strong effort to convert wastes and by-products into useful products for animal feeds, human foods, pharmaceutical products, fertilisers and biodiesel generation. So far, there have been many reports on the deep processing of fresh bone, but there is a lack of research on the ham bone. As we all known, the flavor and nutritional content of ham bone has been changed after pickling. Although the bones can release nutrients when cooking, they are not suitable for direct use in traditional cooking because of their high salt content. Their costs can be balanced through innovation to generate added value products that increase its profitability. This experiment was performed to study the effect of different extraction methods on the release of taste compounds in Jinhua ham bone, three different extraction methods including high-pressure, enzyme treatment, flash extraction and their synthesis were employed. Descriptive sensory analysis was applied to investigate variations of the taste attributes. The composition and content of soluble sugar, organic acid, nucleotide and free amino acid were detected by high performance liquid chromatography (HPLC). At last, partial least squares regression (PLSR) was performed to determine the correlations among the sensory attributes and taste compounds. The sensory analysis results indicated that the sample treated by high-pressure had stronger umami and salty attribute, the sample by enzyme treatment had the strongest sweetness and sourness attribute, and flash extraction treatment gave the most bitterness. Also, the highest acceptability score was shown in the high-pressure treatment sample. It was found that the content of all taste substances in the original sample was the lowest, and the total soluble sugar content was the highest in the sample treated with high-pressure complex enzyme hydrolysis. Compared with other treatments, the organic acid content of the sample after enzymatic hydrolysis increased significantly (P<0.05). Similarly, the total amount of 5 '-nucleotides and free amino acids increased significantly (P<0.05) after the sample was processed, and the highest content was found in high-pressure treatment. The PLSR results showed that there were significant differences (P<0.05) between the samples, the distribution rules of taste substances released by different treatment methods were significantly different. Among which high-pressure sample had significant correlation with umami and salty attribute (P<0.05), and enzyme treatment sample was positively correlated with sweetness and sourness due to high amount of glucose, malic acid, citric acid, cysteine and lysine, while the other processed samples had weak correlation with sensory attributes and taste substances. In general, different treatment of jinhua ham bone has different flavor, its flavor characteristics are related to a variety of substances. The results of this study can provide some references for the improvement of fragrant quality in ham bone and increased the added value of ham bone. [ABSTRACT FROM AUTHOR]

In this paper, the effects of different storage periods on the structure of soy protein isolate (SPI) were studied, and the effects of storage period on the quality of qianyetofu were discussed. The content, subunit, sulfhydryl group, gel texture and sensory evaluation were determined for SPI in different storage periods, and the SPI secondary structure, disulfide bond configuration and side chain structure were analyzed by Raman spectroscopy. The measurement was carried out, and the microstructure of qianyetofu was observed by scanning electron microscopy. The results showed that with the prolongation of storage period, the content of SPI carbonyl increased gradually; the content of disulfide bond in free sulfhydryl group and total sulfhydryl group decreased gradually; the content of secondary structure changed; the hardness of gel showed a downward trend. The sensory evaluation of qianyetofu deteriorated in terms of taste, color and flavor; the gel network structure became looser, the degree of crosslinking decreased and the network structure was rough. This indicate that the SPI has undergone an oxidation reaction during the storage period, resulting in a change in the structure of the soybean protein, which ultimately reduces the gel properties. According to Raman spectroscopy, the analysis of soy protein isolates in different storage periods showed that the α~helix and β~sheet configurations were higher during the storage period of 0-18 days, and the intermolecular disulfide bonds were converted into intramolecular disulfide bonds. During the storage period of 18-30 days, the random coil configuration increased significantly, and the disulfide bond was converted from intramolecular to intramolecular. At this time, the secondary structure of soy protein was loose and the protein gel strength was low. During the whole storage process, the carbonyl content increased gradually, SPI may react during storage to produce reactive oxygen species or free radicals, which attack proteins, causing breakage of the main peptide chain or oxidation of side chain groups, resulting in elevated carbonyl content, protein carbonylation leading to changes in protein structure, the content of sulfhydryl groups and disulfide bonds decreased gradually, oxidation can change the redox state of cysteine in proteins and the equilibrium constant of thiol/disulfide bond interactions, thereby changing distribution of sulfhydryl and disulfide bonds in proteins, and the subunits of 65, 62, 57 and 20 kDa belonged to the bands, it indicates that long-term storage leads to the formation of insoluble high molecular weight oxidized aggregates of soy protein, making them unable to enter the electrophoresis gel, and non-disulfide bonds participate in the formation of oxidized aggregates, which were related to the large aggregate formed by oxidative attack of SPI. Observing the combination of the microstructure of qianyetofu and the sensory evaluation of texture characteristics, it is concluded that the soy protein is oxidized and attacked to form oxidized aggregates, which affects the processing characteristics of the protein, which is the reason for the decrease of gel strength and poor taste. This indicates that the SPI has undergone an oxidation reaction during the storage period, resulting in a change in the structure of the soybean protein and a decrease in its gel properties. [ABSTRACT FROM AUTHOR]

Yak is mainly distributed in the Qinghai-Tibet Plateau, and there are more than 16 million yaks in China, which accounts for approximately 95% of the world’s yaks. Approximately three million yaks are slaughtered per year and the production of meat (skeletal muscle) is approximately 350 thousand tons, while the production of by-product (stomach, intestines, and other internal organs) is approximately 60 thousand tons. At present, those by-products are consumed as low-value products, and the price of by-products is much lower than that of meat, thus, increasing the edible and economic value of by-products is essential. In fact, smooth muscle belongs to a category of muscle tissue that is widely distributed in animal stomach, intestines, and other internal organs. However, smooth muscle has not been treated as meat. Therefore, enhancing the meat value of smooth muscle is a significant goal. In order to investigate the effect of age on collagen content and texture characteristics of yak rumen smooth muscle. The total, soluble, insoluble collagen content, solubility, cross-linking degree, shear force and texture of 1 - 6 years yak rumen smooth muscle were measured. The results showed that the yak rumen smooth muscle total, insoluble collagen and pyridinoline collagen content were significantly increased with the age increase (P<0.05), and the increased rate were 7.61%, 33.86% and 196.46%, respectively. However, soluble collagen content and collagen solubility of yak rumen smooth muscle were significantly decreased with the age increase (P<0.05), and the decreased rate were 30.80% and 35.72%, respectively, which showed the cross-linking degree of yak rumen smooth muscle increased with age increase, while collagen solubility of yak rumen smooth muscle decreased with the age increase. The shear force, hardness and chewiness of yak rumen smooth muscle significantly increased with the age increase (P<0.05), and the increased rate were 96.48%, 91% and 102%, respectively, while cohesiveness, springiness and gumminess of yak rumen smooth muscle were significantly decreased with the age increase (P<0.05), and the decreased rate were 25%, 32% and 39%, respectively, which showed the texture of yak rumen smooth muscle decreased with age increase. Correlation analysis confirmed that the age of yak rumen smooth muscle had a positive significant correlation with the total collagen content, cross-linking degree, shear force, hardness and chewiness (P< 0.01), and had a negative significant correlation with soluble collagen content, collagen solubility, cohesiveness, springiness and gumminess (P<0.01). Moreover, collagen solubility and cross-linking degree of yak rumen smooth muscle had significant effect on shear force and texture (P<0.01). In summary, age of yak rumen smooth muscle had significant effect on the content, solubility, cross-linking degree of collagen and texture. Texture worse with the age increase of yak rumen smooth muscle. Collagen solubility and cross-linking degree of yak rumen smooth muscle had significant effect on shear force and texture. The rumen smooth muscle had suitable eating quality when the yak three years old. Our research identified the collagen content and texture characteristics change rules of smooth muscle at different ages, and the influence of collagen content and texture characteristics, which will provide theoretical basis and data support for the smooth muscle product development and quality control. [ABSTRACT FROM AUTHOR]

Soy protein isolate (SPI) is economic renewable material due to its degradability, high safety, special nutritious and healthcare function. It is ideal raw material to prepare edible films. Despite of a strong performance of air resistance and oil resistance, SPI is poor in terms of its mechanical strength and moisture resistance. In order to obtain a high quality SPI edible film in the experimental study, the optimal comprehensive score of edible film was used as the objective. And the total score of edible film depends on the elongation, tensile strength, water vapor permeability, oxygen permeability. Through consulting a large number of the edible film literatures, we found that the low temperature plasma can improve the quality of edible film. Therefore, the treatment of low temperature plasma can improve the mechanical properties, water vapor permeability and oxygen permeability coefficient of SPI film. And the comprehensive score of edible film was affected. In order to narrow the scope of the experiment, the single-factor experiment is conducted to study the influence of plasma treatment time, the pH value of membrane-forming materials and glycerol concentration. After considering the change of elongation, tensile strength, water vapor permeability and oxygen permeability, the range of data suitable for the next experiment is obtained. At this time, we will reduce the pH value to 9-11. At the same time, the amount of added glycerol concentration was determined as 0.015-0.025 g/mL. The experimental range of plasma time was 6-12 min. At this point, the experiment entered the critical moment. That is, we use principal component analysis and the comprehensive score of membership. Principal component analysis of experimental data is performed using SPSS software. Then the results obtained from the main component analysis are summarized. We can get the weight of each factor by combining the characteristic root, the variance contribution rate and the load matrix coefficient. Among them, the weight of elongation is 0.19, the weight of tensile strength is 0.22, the weight of water vapor permeability coefficient is about 0.29, and the weight of oxygen permeability rate is about 0.3. And we can get the comprehensive score of the edible film by the comprehensive score method. By using Design-Expert software to analyze and evaluate the comprehensive score of edible film, we can make a further analysis of the experimental data. Through the analysis of model, the influence degree of various factors on edible membrane is in the following order: pH value > glycerol concentration > plasma treatment time. Under the conditions of plasma processing time of 11.31 min, glycerin concentration of 0.02 g/mL and pH value of 11, the overall physical properties of edible films were the best with a score as high as 0.90, and the elongation, tensile strength, water vapor permeability and oxygen permeability of the edible films were 37.77%, 3.46 MPa, 1.81×10-12 g/(cm·s·Pa) and 1.43×10-5 cm3/(m2·d·Pa) respectively. The edible film was observed by atomic force microscopy and contact angles. The results showed that the edible film treated with low temperature plasma increased the roughness and decreased the contact angle. The plasma effect can effectively improve the mechanical properties and surface wettability of the SPI membrane. The results of this paper can provide the new reference for the development of edible films. [ABSTRACT FROM AUTHOR]

Crude protein is the key indication for evaluation of the quality and feeding value of pasture grass. Estimating crude protein content of pasture grass is necessary for monitoring grassland nutrition status, sustainable utilization and management of grassland resources, eventually preventing grassland degradation. Hyperspectral remote sensing technology is supplied as a new approach for scientists to study properties and processes of ecosystems and their inner biochemical content variation. In view of the limitation of ground remote sensing and astronautics remote sensing, we try to construct estimation model of pasture crude protein content based on the hyperspectral aerial airship imaging system, in order to meet the application needs of smart animal husbandry. In view of the uncertainty problems of traditional biochemical parameter inversion models and practical application needs in agriculture and animal husbandry production, we propose a multi-step pasture crude protein content estimation model, which combined the equal width interval division method, stepwise discriminant analysis and Fisher discriminant method. An experiment was designed to determine whether pasture crude protein content could be predicted by means of the developed strategy. Jinyintan grassland, a typical prairie in Haiyan County, Qinghai Province was chosen as the research area. The hyperspectral data were acquired with the hyperspectral mapping system installed on an airship (named ASQ-HAA380), which was developed by our research group. Pasture crude protein samples were collected at the same time and analyzed in Qinghai University. The results show that the proposed model can accurately estimate the crude protein content of pasture. The test accuracy of the 3 models with different interval numbers (3, 5, and 7) for all samples is 95%, 95% and 85% respectively, while their corresponding cross-check accuracy is 90%, 80% and 65% respectively. Compared with the traditional stepwise linear regression method, the estimation accuracy also has a great improvement (overall test accuracy is increased by 18.7%-70%, and cross test accuracy is increased by 20%-62.5%). The selected bands of the 3 models with different interval numbers (3, 5, and 7) are 870, 815, 802, 737, 391 nm; 988, 391, 398, 405, 548 nm; and 870, 815, 946, 888, 839 nm respectively. In addition, we can adjust content interval range according to different application requirements. And our experimental results indicate that the model accuracy is inversely proportional to interval number. In general, this paper has successfully realized the accurate estimation of the crude protein content of pasture with hyperspectral aerial airship imaging data, which provides reference and technical basis for quantitative estimation of crude protein content and efficient implementation of precision livestock husbandry based on hyperspectral images, and also lays the foundation for the development of intelligent livestock husbandry in the future. [ABSTRACT FROM AUTHOR]

Nowadays, formaldehyde-based adhesives are still widely used in wood industry, such as urea formaldehyde resin, phenol formaldehyde resin, melamine formaldehyde resin. Emission of toxic formaldehyde is still one of the biggest problems for these formaldehyde-based adhesives in recent years for the development of wood adhesives. Lately, there has been a considerable industrial interest in the development of natural or green wood adhesives, such as lignin, tannin, protein, starch, and polysaccharides, to substitute synthetic thermosetting resins as adhesives for wood panels because of the mounting environmental pressure worldwide. As one kind of bio-based adhesives, soy protein-based adhesive has been always a hot topic since 1990s. As it is well-known that the soy-based adhesive with no modification cannot be used directly for wood panels for its poor bonding strength and water resistance especially, and the latter one is so bad. Cross-linking modification has been proved to be an effective modification method to improve the water resistance of soy-based adhesive. Some cross-linkers have to be used for this modification, such as formaldehyde-based resins, polyacrylic ester, epoxy. As a biomass material, furfuryl alcohol is more friendly than formaldehyde-based crosslinkers for protein-based adhesive. To guide the preparation of protein-based adhesive, especially the soy-based adhesive, the reaction between a simple dipeptide N-(2)-L-alanyl-L-glutamine (AG), used as a model compound of protein, and its cross-linker furfuryl alcohol was studied in this paper. The products prepared with furfuryl alcohol and AG under different pHs were analyzed by ESI-MS (electrospray ionization mass spectrometer), 13C-NMR (carbon-13 nuclear magnetic resonance) and FT-IR. It was found that the medium environment had great effects on the competition of the co-condensation reaction between furfuryl alcohol and AG and self-condensation reaction of furfuryl alcohol molecules in the mixing system with furfuryl alcohol and AG. Under alkaline conditions, both co-condensation and self-condensation were not obviously detected. Only when the value of pH was higher than 11, a few co-condensation reaction products were gotten. The reaction occurred mainly between furfuryl alcohol and the primary amido groups of AG. Under acid conditions, both co-condensation and self-condensation were observed. The more acid the preparation conditions, the easier to be observed the self-condensation of furfuryl alcohol molecules than the co-condensation between furfuryl alcohol and AG. And when the value of pH was higher than 5, both co-condensation and self-condensation were not outstanding. In this study, under pH value 3, the co-condensation and self-condensation found equilibrium. There was a great possibility for the primary amido and aliphatic amino groups of AG molecules to react with furfuryl alcohol molecules. No reaction was detected between the secondary amido groups of AG and furfuryl alcohol. Besides, the reaction mechanism between furfuryl alcohol and model compounds of soy protein had correspondence with the performance of plywood with soy protein-based adhesive, namely, soy protein-based adhesive crosslinked by furfuryl alcohol showed better bonding performance and water resistance under the pH value of 3 than that of others. In conclusion, the research has great significance to realize the scientific use and improve the market competitiveness of soy protein-based adhesives. [ABSTRACT FROM AUTHOR]

Tartary buckwheat protein is the main bioactive substance in tartary buckwheat. It has the advantages of antibacterial activity, anti-tumor, lowering blood pressure, and inhibiting serine protease and other physiological activities. It is an ideal healthy food raw material. At present, the heating treatment methods are wet-heat, dry-heat and microwave method. In order to maximize the maintenance of food functional characteristics, it is very important to study the effect of different heating treatment methods on the tartary buckwheat products. Wet-heat treatment: Tartary buckwheat protein were mixed with water according to the ratio of solid to liquid 1:10, the temperature of water bath was 80、100 ℃, the treatment time was 20 min, 40 min, 60 min, freeze-dried. Dry heat treatment: the tartary buckwheat protein tile on the enamel plate, placed in the oven, the temperature 80、100 ℃, treatment time was 20 min, 40 min, 60 min. Microwave heating treatment: the tartary buckwheat protein placed in a microwave oven (700 W), treatment time was 2 min, 4 min, 6 min. In this paper, tartary buckwheat seeds were crushed, degreased, with flavonoids removed, then the supernatant was taken and the pH value was adjusted to the isoelectric point, and the precipitate was freezing-dried in vacuo to give tartary buckwheat protein. The tartary buckwheat protein was prepared by wet-heat, dry-heat, microwave treatment. The changes in physical and chemical properties and functional properties of tartary buckwheat protein, such as hydration properties, emulsifying activity, foaming activity, in vitro digestibility, antioxidant activity and bile salt adsorption capacity were measured. The experimental results show that the traditional heating methods (wet-heat, dry-heat) and short-term microwave treatment have a certain improvement on the functional properties of tartary buckwheat protein. Among them, the wet-heat treatment has positive effects, especially for emulsification, emulsifying stability, foaming property, foam stability, hydroxyl radical (·OH) scavenging ability, and sodium taurocholic acid adsorption ability, which were increased by 28%, 22%, 22%, 23%, 9.75% and 28%, respectively. Dry-heat treatment can improve the water holding capacity and the reducing power of tartary buckwheat protein, which are 31% and 16.34% higher than that of untreated tartary buckwheat protein. For short-term microwave treatment (2 min), the water holding capacity of tartary buckwheat protein was increased by 51%. And long-term microwave treatment (4、6 min) has a greater negative impact on the tartary buckwheat protein performance, especially for emulsification, emulsifying stability, foaming ability, and foam stability, which were reduced by 62%, 77%, 66% and 54%, respectively; ABTS radical scavenging ability, .OH scavenging ability, and reducing power were reduced by 48.79%, 63.49% and 49.18%, respectively; adsorption ability of sodium bile acid, sodium deoxycholic acid and sodium taurocholic acid was reduced by 64%, 55% and 41% respectively. In summary, in the process of tartary buckwheat protein processing, you can choose the traditional heating method or strictly control the microwave time to avoid the damage of long-term microwave heating to the buckwheat protein functional characteristics. The results can provide theoretical and experimental basis for the further study of the application of tartary buckwheat protein in functional food. [ABSTRACT FROM AUTHOR]

Curing has important functions in meat products, which contributes positively to the structural and sensory characteristics of the meat. By various curing methods, a wide variety of cured meat products are produced. Considering the processing time or the weight ratio of brine to meat needed to obtain a product with better characteristics from a sensorial or a structural point of view, neither scientists nor manufacturers came to a similar standpoint. Nowadays, to some extent, reducing curing time and improving the curing operations may be achieved through tumbling or other methods. From a production perspective, fast tumbling can shorten processing time and is favorable, but it can lead to more heat production and products of poor quality. Ultrasound is a novel processing technology which may accelerate mass transfer through the mechanism of cavitation in meat tissue. Ultrasound is also favorable from an eating point of view since it results in more tender and juicy meat. In order to explore novel curing processing for shortening curing time and improving product quality, we assessed the effects of pressure-transform tumbling curing assisted with ultrasound (PTU) technique on the protein secondary structures, moisture distribution and microstructure of chicken. For this purpose, fresh chicken breasts were selected (50±1 g, 5 cm × 5 cm × 2 cm) and treated at 4 ℃ for 100 min with one of the 3 following curing treatments: (1) static brining, (2) vacuum tumbling (VT) (rotation speed of 16 revolutions per minute, 0.08 MPa, 100 min, 15 minutes of continual work and then 5 minutes of resting period), or (3) pressure-transform tumbling assisted with ultrasound (40 kHz, 140 W; parameter setting was consistent with the VT curing, and the only difference was the ultrasound treatment of the meat samples carried out by activating ultrasonic probe during the resting period). The ratio of meat weight to brine weight was 100: 30 (g/mL) for all treatments. The brine solution was composed of 2% NaCl, 0.3% compound phosphates, 250 mg/kg sodium ascorbate and 150 mg/kg sodium nitrite (relative to meat weigh). The results showed that the proportion of α-helix was reduced greatly (P<0.05), and the amount of β-sheet and β-turn were increased (P<0.05) after PTU treatment. The LF-NMR (low-field nuclear magnetic resonance) data indicated that the transverse relaxation time of the bound water (T21) and immobilized water (T22) was clearly reduced by PTU compared with VT and static brining. Moreover, the proportion of peak area of T21 was significantly increased (P<0.05) for PTU treatment, which indicated that the water molecules were combined with protein more tightly and part of free water was turned into immobilized water. SEM (scanning electron microscopy) and TEM (transmission electron microscope) showed that PTU could result in severe degradation of myofibril and larger distance between muscle fibers compared to static brined or VT samples. Based on this study one can conclude that PTU treatment can serve as a useful alternative to tumbling for improving curing in meat tissue as well as enhancing water-holding capacity and textural properties. The research provides a theoretic basis and practical application reference for the PTU technology in the meat industry and related equipment design. [ABSTRACT FROM AUTHOR]

Capsicum seed protein isolate is a new type of plant protein resources. From this research, the protein isolate was separated into water-soluble(WS), salt-soluble(SS), alkaline-soluble(AS) and ethanol-soluble(ES) fractions. Water-soluble and ethanol-soluble fractions were the major constituents, about more than 75% of the total protein. This paper focused on ultrasonic-assisted extraction technology of extracting protein isolate from capsicum seed. Response surface methodology was used to determine optimum conditions for protein extraction. The experiments designed 29 groups of different conditions to extract protein from capsicum defatted flours. Independent variables which would affect protein extracting rate were discussed, such as pH (7, 8, 9, 10 and 11), ultrasonic power (200, 300, 350, 400 and 500 W), extraction time (10, 15, 20, 25 and 30 min) and material-solvent ratio (1:10, 1:20, 1:30, 1:40 and 1:50). The model equation was set up. In the model equation, the coefficient of association (R2) was 0.9748, indicating it's a reasonable matching to the experimental data. The optimized conditions were as follows: pH value was 11, ultrasonic power was 336.21 W, extraction time was 13.31 min and the material-solvent ratio was 1:35.58. According to this optimized condition, the extraction rate of protein isolate was 5.90 g/(100 g) defatted red pepper seed. Due to the limitations of experimental facilities, the optimized conditions were modified. The results were as follows: pH value was 11, ultrasonic power was 350 W, extraction time was 13 min and the material-solvent ratio was 1:36. The optimum conditions were verification. The results showed that extraction at the modified conditions gave a protein yield at 6.05 g/(100 g). The experimental values were found to be in agreement with the predicted ones. Analysis of variance (ANOVA) of independent variables was performed. The statistical analysis data revealed that linear, quadratic and interaction terms was significant (P<0.05). The lack of fit test measured the failure of the model to represent data in experimental domain at points which are not included in the regression. There was a non-significant lack of fit that further validates the model (P > 0.05).The significance of each coefficient was determined using the t test and P value. pH value and solvent/meal ratio were the most significant factors (P<0.001). Also, interaction effect of pH and extraction time, interaction effect of extraction time and materials/solvent ratio were both significant (P<0.05). The ultrasonic power was not significant factor (P>0.05). The main factors were analyzed by Design software, which could affect the yield of protein. The results were as follows: pH value>material/solvent ratio>extraction time>ultrasonic power. Compared with traditional extraction methods, the extraction yield of protein increased from 5.24 to 6.05 g/(100g), while the purity of capsicum seed protein isolate enhanced from 78.46% to 83.93% by ultrasonic-assisted method. These results give the advices in processing protein from capsicum seeds according to optimized condition. Furthermore, it provides a theoretical reference for the industrial production and application of capsicum seed protein isolate. [ABSTRACT FROM AUTHOR]

Irradiation is a kind of effective food sterilization technology, which can effectively inhibit and eliminate the pathogenic or spoilage microorganisms. Meat and meat products, due to their high level of nutrients, pH value (5.5-7.0) and high water activity, offer a congenial environment for the growth of bacteria. In recent years, the utilization of irradiation in ready to eat (RTE) meat products is gradually getting people's attention, because many of the ready-to-eat cooked meat products are sterilized by high temperature above 100 ℃, which may could cause the nutrition loss and flavor deterioration. Pork ham sausage is a kind of important cooked meat product, which has won good graces of many peoples. Thus, this study mainly used the γ-irradiation for pork ham sausages preservation to investigate the effect of different irradiation doses on the preservative effect of pork ham sausage, and finally chose a suitable irradiation dose for pork ham sausages. The study mainly irradiated the pork ham sausage using the γ ray of 60Co at 1, 3, 5, 7 or 9 kGy, respectively. After irradiation, the pork ham sausages were stored immediately at 4 ℃ for 4 weeks, and the changes of lipid oxidation (TBARs), protein oxidation (carbonyl value), color, pH value, TVB-N content and total microbial counts were measured during the storage. Through analyzing these indices, the effect of different irradiation doses on pork ham sausage was discussed, and a suitable irradiation dose for the pork ham sausage was chosen. The results showed that irradiation could effectively decrease the oxidative stability of the lipid and protein of pork ham sausage, which consequently promote the lipid and protein oxidation of the pork ham sausage during storage at 4 ℃, and the effect was enhanced with irradiation dose increase. Due to the influence of irradiation on lipid and protein oxidation, the color of the samples was also affected by irradiation. But 1 kGy irradiation had no a significant effect on the color of pork ham sausage. 3 to 9 kGy irradiation could significantly decreased the a* value and increased the L* value compared to the control sample (P<0.05), and both of them decreased gradually with storage time increasing. The decrease rate of high dose irradiation groups was faster than that of low dose irradiation groups. The pH value of samples was not significantly affected by the irradiation dose (P>0.05) and also not changed significantly during the cold storage, which just changed within the range of 6.0-6.5. For all samples, the TVB-N content increased with storage time increase. But for irradiated samples, the increase rate was significantly lower than that of the control sample. And when the irradiation dose increased to 5 kGy, the inhibitory effect of irradiation on the TVB-N formation was not changed significantly with the continually increase of the irradiation dose. This result was very consistent with the microbiological analysis result. These results suggests that 5 kGy irradiation can play an effective inhibitory effect on the microorganisms of pork ham sausages, and will be a very promising ham sausage preservation technology. [ABSTRACT FROM AUTHOR]

Soy protein isolate (SPI) is an important highly purified commercial soy protein product, and has been widely used in food manufacturing owing to its good nutrition and abundant availability. However, application of SPI is still restricted due to its poor solubility and interfacial properties. Dynamic high-pressure microfluidization (DHPM) is an emerging physical technology widely used to modify the functional properties and structure of protein. It is an available method using the combined forces of high-velocity impact, high-frequency vibration, instantaneous pressure drop, powerful shear, cavitation force and ultra-high pressures. In recent years, DHPM has been successfully used for improving the functional properties of whey protein, rice protein, SPI, as well as used to increase the enzymatic hydrolysis of soy isolated protein and the emulsifying properties of hydrolysates, and improve the extraction yield of polyphenols and polysaccharides from plant materials. Our previous research indicated that DHPM treatment at 20-160 MPa could significantly change the solubility, foaming and emulsifying properties, and decrease the average particle size of SPI. Moreover, DHPM could promote the glycation reaction between bovine serum albumin and glucose. In addition, it was found that high pressure homogenization could improve the foam overrun of soy protein isolate – hydroxypropyl methyl celluloses dispersed systems and potentially create new functional aggregates. Soybean soluble polysaccharides (SSPS) could bind with protein via electrostatic and hydrophobic interactions, and stabilize the protein-polysaccharide complexes in aqueous solution. Therefore, for improving functional properties of SPI, the influence of DHPM in various pressures on the functional properties of SPI in the presence of SSPS, namely SPI-SSPS system, was investigated in this work. The SPI-SSPS was processed at 0, 60, 100, 140 and 180 MPa of DHPM treatment, respectively. The foaming and emulsifying properties, as well as solubility, particle size distribution and surface hydrophobicity of SPI-SSPS were detected to evaluate the influence. The results indicated that DHPM treatment improved the solubility and foaming properties of SPI, and the presence of SSPS greatly strengthened these effects (P<0.05). Samples subjected to 100 and 60 MPa treatments showed the best foaming ability and foaming stability, which were 1.2 and 2.4 folds of that from untreated sample, respectively. DHPM treatment at 140 MPa yielded the highest solubility, which was 1.8 folds of that from control. However, DHPM processing significantly decreased emulsifying properties, particle size distribution and surface hydrophobicity of SPI-SSPS (P<0.05). With DHPM pressure increasing, average particle size and surface hydrophobicity of SPI-SSPS gradually declined. Moreover, the smallest average particle size and the lowest fluorescence intensity were obtained at 180 MPa treatment. In some way, the reduced surface hydrophobicity could be used to explain the increased foaming properties and the decreased emulsifying properties. To show good foaming, the protein must be capable of migrating at the air-water interface, unfolding and rearranging at the interface. With surface hydrophobicity decreasing, more hydrophilic groups were unmasked, causing that the protein was kept better touching with water molecule and developed to strong film at the air-water interface. For emulsifying properties, surface hydrophobicity was able to influence the ability of the protein to be adsorbed to the oil side of the oil-water interface. Lower hydrophobicity of the protein led to weaker adsorption with consequent worse emulsion capacities. However, in this work, the surface hydrophobicity was not highly correlated with the emulsifying or forming properties as suggested by the different changing trends of them under the varying pressure of DHPM. It indicated that surface hydrophobicity may not be the only factor that causes the changes in the emulsifying or forming properties. Above findings suggest that DHPM processing combined with SSPS is a potential alternative to modify certain functional properties including solubility and foaming properties of SPI to extend its application in food industry. The results in this study can give the reference for the functional modification of SPI. However, further research is needed to elucidate the detailed mechanism of DHPM processing on the interfacial properties of SPI-SSPS, as well as the interaction between SPI and SSPS. [ABSTRACT FROM AUTHOR]

In order to investigate the physicochemical and application quality changes of wheat damaged by Rhizopertha dominica in different growth stages, the nutritional properties, dough rheological properties, food processing properties and other relevant quality indices of wheat were determined after infestation by Rhizopertha dominica in the egg stage, larval stage, pupa stage and adult stage under the optimal growth conditions such as the temperature of (32±1)℃ and relative humidity of 75%±1%. And all data were processed by the differential analysis method. The results showed that the ash content of the wheat firstly decreased and then increased after infected by Rhizopertha dominica from the egg to the adult stage, and the ash content between the infested wheat sample in the pupal and adult stage and the control sample showed a significant difference (P<0.05). The albumin and reducing sugar content had a tendency of increasing firstly and then decreasing, and the albumin content between the infested wheat sample in all development stages and the control sample showed significant difference (P<0.05), while the reducing sugar content had not significant difference. The crude fat content and glutenin content decreased gradually, and the crude fat content between the infested wheat sample in all different development stages and the control sample showed significant difference (P<0.05), while the glutenin content between the infested wheat sample in the larval, pupa and adult stage and the control sample had significant difference (P<0.05). The globulin and gliadin content irregularly changed, and the globulin and gliadin content between the infested wheat sample in the larval, pupal and adult stage and the control sample had significant difference (P<0.05) respectively. In addition, with Rhizopertha dominica eggs growing and developing in the wheat grain kernel, the microstructure of the wheat endosperm showed the interface damaged by Rhizopertha dominica became to have hard texture and rough surface, the structure was softening, the matrix proteins had severe fracture, and the damaged starch gradually increased. The rheological properties of whole wheat flour dough changed obviously, the peak time gradually decreased, and the peak time between the infested wheat sample respectively in the pupal and adult stage and the control sample showed significant difference (P<0.05); the peak height and peak area first decreased and then increased, the peak width had an overall upward trend, and the peak height, front width and peak area between the infested wheat sample in all different development stages and the control sample showed significant difference (P<0.05). The slope of the right side of the midline peak had a tendency of first rising and then decreasing, and the slope of the right side of the midline peak between the infested wheat sample in all different development stages and the control sample had significant difference (P<0.05). The sensory evaluation scores of the steamed bread made with whole wheat flour decreased gradually, and the elasticity, adhesiveness and restorative parameters in texture analysis of the steamed bread decreased, while the hardness, chewiness, gumminess changed irregularly. The differential analysis results indicated that the infestation by Rhizopertha dominica in different growth stages had significant effects on the physicochemical and application quality of wheat (P<0.05). The physicochemical properties and application quality of wheat infested by Rhyzopertha dominica in the larval and adult stages changed more obviously, and the differences with the control sample were more significant (P<0.05). The research results show that the wheat damaged by Rhizopertha dominica in different growth stages can not only cause the change of physical and chemical properties of wheat, but also directly affect their eating quality, and therefore it should pay much attention to the prevention and control of Rhyzopertha dominica in the different growth stages during the wheat storage. [ABSTRACT FROM AUTHOR]

As a kind of the stored grain insect pests bored inside grains, the damages caused by Rhyzopertha dominica are very serious in the process of wheat storage, and it has severe impacts to wheat quality in many aspects, such as starch, lipid, protein, and so on. In order to explore the effects of infestation by Rhyzopertha dominica in different growth and development stages on wheat storage protein structure, and provide some references for the detection of wheat quality and the growth and development of stored grain insect pests in the process of wheat storage, the wheat infected by Rhyzopertha dominica was taken as the research material. The glutenin macropolymer content, Zeleny sedimentation value, gluten moisture capacity and protein secondary structure were inspected and analyzed, as well as the content of thiol (-SH) and disulfide bond (-S-S-)and gluten microstructures of wheat infected by Rhyzopertha dominica in different growth and development stages i.e. egg stage, larval stage, pupa stage and adult stage. The results showed that in the 4 growth and development stages of lesser grain borer, the Zeleny sedimentation value, glutenin macropolymer conten and β-turn had an increasing trend in general, while the content of -SH and β-pleated sheet showed a completely opposite change trend. The gluten water absorption capacity, and the content of -S-S- and α-helix showed a downward trend first and then an upward trend, and the change of random curl content showed an opposite trend. The lesser grain borer in the egg stage did less harm to wheat storage protein structure, and just the gluten water absorption capacity and β-turn content had a great change (P<0.05), while the lesser grain borer in larval stage and pupa stage had a serious damage to wheat storage protein structure. Compared to the control samples of the insect-free wheat with the relevant infection stages under the same experimental conditions, the Zeleny sedimentation value, content of glutenin macropolymer, β-turn and random curl of wheat infected by lesser grain borer in the larval and pupa stages increased significantly (P<0.05), but the gluten water absorption capacity, content of -SH and -S-S-, α-helix and β-pleated sheet decreased (P<0.05). In addition, the microstructure analysis results showed that the micro fiber filament increased and the surface of gluten got rough, the structure got loose and scattered, and the structure fracture became more and more severe with the growth and development of lesser grain borer. Until the stage of adult, some microstructure of gluten could not even be identified. All the experiment results show that the damages on wheat protein structure are severe with the growth and development of lesser grain borer inside wheat granules. Accordingly, timely control on lesser grain borer is necessary and it will reduce the damage to wheat storage protein structure before infestation by Rhizopertha dominica in the larval and pupa stages. The research results provide the reference for the control of the lesser grain borer for the wheat during the storage. [ABSTRACT FROM AUTHOR]

In this paper, myosin in pork was extracted as the object of the research, and the purity of the protein was analyzed by sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE); the effects of variable heating strength on the total sulfydryl content (T-SH), the secondary structure and the surface hydrophobicity of myosin were detected by Raman spectroscopy and fluorescence spectroscopy. Eight typical meat flavor compounds were added to the myosin solutions to form a myosin-flavor compound interaction system. Taking the ratio of flavor compounds relative content as index, the influence of different heating strength on the flavor binding ability of myosin was studied by means of solid-phase microextraction - gas chromatography - mass spectrometry (SPME-GC-MS), providing a reference for future research on the formation mechanism of meat flavor. The results showed that heat treatment had significant effect on the absorption and release of various flavor compounds, through changing myosin conformation to hit the mark what we wanted to achieve; when the temperature was adjusted up to 55℃, the myosin molecules were unfolded obviously, resulting a conversion from α-helix and β-sheet to β-turn and random coil. However, as the temperature continued to increase to 75℃, the myosin molecules degenerated and the process showed the reverse change, that was to say, there was a transition from β-turn and random coil to α-helix and β-sheet. In the procedure when the temperature was raised to 45℃, the amount of protein sulfydryl group remained stable, but there was a marked reduction when further improving the temperature to 80℃, resulted in protein aggregating because a small part of sulfydryl converted to disulfide bond; the surface hydrophobicity of myosin continued to increase dramatically during the course of the temperature going up to 65℃ and then many hydrophobic residue groups would be exposed at the molecular surface, however, when the temperature rose, its surface hydrophobicity decreased slightly, indistinctively; myosin’s binding ability to 3-methyl butaldehyde, pentanal, heptanal and octanal was enhanced with the protein unfolding and decreased with the protein degenerating. Besides the hydrophobic group and hydrogen bond, sulfydryl group played a considerable role in affecting the binding ability of myosin to aldehydes. On the one hand, the binding ability of myosin to 2-pentanone presented a trend of first decreasing and then increasing on the whole, in which it showed the lowest binding ability under the condition of 45℃ and the fastest binding under 85℃; on the other hand, their binding ability between myosin and 2-heptanone, 2-octanone or 2-nonanone demonstrated a trend of increasing, decreasing, and then increasing again, and the binding ability reduced to the minimum while myosin degenerated at the temperature of 75℃, and the binding ability rose to the highest at the temperature of 85℃ compared to other conditions. To sum up, the binding ability of myosin to ketones mainly depends on the hydrophobic properties. [ABSTRACT FROM AUTHOR]

Corn protein concentrates (CPC) were prepared continuously from corn gluten meal (CGM). Firstly, sub-critical fluid and α-amylase were used to remove crude fat and degrade starch. Then, the resultant protein suspension was concentrated and separated by ultra-filtration membrane. The ultra-filtration membrane process was used to remove the impurities produced by the first process such as soluble carbohydrate. The concentrated protein suspension was incubated with 0.2 M citric acid and treated by jet cooking device at 140°C for 90 s. Finally, 3 samples could be acquired by spray-drying process. In order to study the effect of jet cooking on the functional properties of CPC, solubility profile, deamidation degree, and amino acid composition were investigated. Moreover, the digestibility in vitro and the antioxidant activity of digestive product were investigated. We expected to provide an effective and continuous process technology for the application of CGM, and prepared a kind of CGM which exhibited excellent functional properties and digestibility in vitro. The results showed that protein content of CGM was improved after the removing of crude fat and starch. However, there was no difference among CPC, JC-CPC (jet cooking CPC) and HT-CPC (heat treatment CPC) in the amino acid composition, protein content and recovery rate (P>0.05). The results of solubility suggested that CPC, HT-CPC and JC-CPC exhibited a typical U-shaped solubility curve, with the minimum at the pH value of 5.0-6.0 and gradually increasing at the pH value below 4.0 and above 7.0. When the pH value was below 4.0 and above 7.0, the solubility of JC-CPC was superior to CPC and HT-CPC. These results may be ascribed to the effect of deamidation that led to translate insoluble amino acid (Asn or Gln) to soluble amino acid (Asp or Glu), and the high temperature and high shear force during the treatment of jet cooking process which made the protein unfold and disaggregate. And owing to the effect of high temperature and high shear force during the jet cooking process, the foaming capacity and the foaming stability of JC-CPC were improved significantly (P<0.05) compared to CPC and HT-CPC. In the process of digestion in vitro, the nitrogen release of 3 samples increased rapidly at the beginning, and then gradually slowed down. After digestion, the nitrogen release of JC-CPC cloud reached up to 62.05%±0.75%, higher than the CPC (21.02%±0.19%) and HT-CPC (40.25%±0.72%) (P<0.05), and the degree of hydrolysis cloud reached up to 24.02%±0.49%, higher than the CPC (9.23%±0.45%) and HT-CPC (14.52%±1.26%) (P<0.05). These results were mainly due to the improvement of protein’s solubility and the protein unfolding which may expose more protease binding sites and hence led to enzymatic hydrolysis more efficient during the jet cooking process. In addition, the reducing capacity of digestive product of JC-CPC was better than that treated by alcalase alkaline protease (P<0.05), while the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) inhibition of JC-CPC after pepsin and trypsin treatment was similar to that treated by alcalase alkaline protease. We can draw a conclusion that the product of JC-CPC after digestion in vitro possesses good antioxidant activity and physiological activity which may be beneficial to human beings, as well as the product treated by alcalase alkaline protease. It also means that the digestive product of JC-CPC cloud can be directly absorbed by human beings in the gastrointestinal tract. JC-CPC exhibits excellent functional properties, and digestibility property in vitro is attributed to the effect of jet cooking. The outcomes of the above research may prove a valid way to the application of CGM in further processing of plant proteins. [ABSTRACT FROM AUTHOR]

Sweet sorghum is a high-energy crop which has many applications, such as producing sugars and fuel ethanol. The sweet sorghum stalk residues are discarded as waste. However, there are fat, protein, crude fiber and other carbohydrates in stalk residues which can be used to make protein feedstuff. To achieve the rapid promotion and large-scale application of producing protein feedstuff using sweet sorghum stalk residues, the solid state fermentation system was used. First, the physical and chemical parameters of the sweet sorghum stalk residues were determined, the total content of cellulose, hemicellulose and lignin was 73.75% (dry weight, the same below) and the crude protein content was 2.27%. Secondly, the combination of Aspergillus nige, Trichoderma reesei, Candida utilis and Lactobacillus casei was optimized. The optimal combination of the strains was selected based on the component change of crude protein, cellulose, hemicellulose, lignin, crude ash and crude fat. The results showed that the fermentation after adding 4 strains was proper. In this condition, the cellulose content decreased by 27.0%, and the hemicellulose content decreased by 15.72%. The crude protein content in the combination added with Lactobacillus casei increased by 26.96%, the crude ash content decreased by 15.49% and the crude fat decreased by 18.15%, compared with those without adding Lactobacillus casei. Third, based on the optimal combination of the strains, 1% and 3% urea were respectively added in the sweet sorghum stalk residues to confirm the optimal content of urea. It indicated that the contents of crude protein and true protein were significantly improved with the addition of 1% urea. The true protein content was increased by 21.90% compared with that without the addition of urea under the same condition. In conclusion, the crude protein content of sweet sorghum stalk residues increased from 2.27% to 7.14% and its true protein increased from 2.01% to 6.41% after 8 days under the raw solid state fermentation along with inoculating 4 strains and adding 1% urea. This study provides an effective process to produce protein feedstuff from the raw sweet sorghum stalk residues feasibly on a large scale. It is helpful to explore an alternative of protein feedstuff in the animal husbandry industry. On the other hand, this can alleviate the environmental pollution caused by the accumulation of the sweet sorghum stalk residues, and has a very promising future. [ABSTRACT FROM AUTHOR]

Agricultural water was stress in Haihe River Basin of China, many peasants had given up farming because of irrigation water shortage during the critical period of crop water requirement, if this trend continues, local food security would be affected. Therefore, profound understanding crop's water requirement rules and improving agricultural water use efficiency is very important. Winter wheat is one of the crops that have the largest acreage and high water consumption during the whole growth period, and occupies an important position in the diet of local residents. Therefore, we conducted a water-controlling field experiment to examine the effects of water deficit on the yield and protein formation of winter wheat during the growth and development stages, and meanwhile determined the better water deficit level at each development stage for the objective of water saving as well as high yield and quality. Two water deficit levels were set up during four growth and development stages including green stage, jointing stage, heading and flowering stage, filling and ripening stage. The two water deficit levels were light water deficit (L, soil moisture content was field capacity 55%-60%, soil water suction was 375-448 kPa) and moderate water deficit (M, soil moisture content was field capacity 45%-50%, soil water suction was 586-687 kPa). Moreover, proper soil water treatment during whole stage (CK) was also set up with soil moisture content being of field capacity 65%-70% and soil water suction 256-305 kPa. Our results showed that comparing with the proper soil water treatment (CK), the filling period shorten by 2.72%-15.78% under the deficit treatments. The time for arriving maximum filling speed were advanced with a range of 2.33%-14.58%. All deficit treatments increased the maximum filling speed and the average filling speed except for the treatments of light and moderate water deficit at the filling and ripening stage, and the maximum values were 15.77% and 12.09%, respectively. The basic trend of protein formation showed a "V-shape" curve, which was unchanged by deficit treatments, protein contents and yields various with water deficit treatment. Protein content increased with the aggravation of water deficit at all growth stages except for the green stage. Moderate water deficit at filling and ripening stage featured with the maximum protein content (14.33%), and the light water deficit at jointing stage with the minimum protein content (12.88%). Proper soil water treatment during whole stage (CK) featured with the maximum protein yield (1047.30 kg/hm2), light water deficit at jointing stage featured with the minimum protein yield (802.77 kg/hm2).These results suggested that giving consideration to winter wheat yield and protein yield both, suitable deficit treatments successively were light water deficit at green stage, moderate water deficit at green stage, light water deficit at filling and ripening stage, light water deficit at heading and flowering stage, moderate water deficit at jointing stage, and light water deficit at jointing stage. Our results are important for providing theory and data to the cultivation of winter wheat for water saving as well as high yield and quality. [ABSTRACT FROM AUTHOR]

Yaks (Bos grunniens) from the Qinghai-Tibetan plateau are the sole source of milk of local inhabitants. In the past years, yak milk has attracted more and more attention, due to its increasing demand. Yak milk is widely used to produce butter, soft and hard cheeses, yogurt, milk powder, Qula, and casein-containing products. Caseins, the major protein in milk, are commonly used in the food, chemical, cosmetic, and pharmaceutical industries. Yak caseins are widely used to produce high quality food ingredients and soaps, glues, leather polishing reagents, and clothing, among others. However, compared to cow caseins, yak caseins have poor solubility, which affects the other functional properties. The poor solubility of yak caseins is mostly attributed to its conformation. Succinylation is the most frequently used modification method, which changes the conformation and increases the net charge of protein, which improves its functional properties consequently. It was indicated that the reaction conditions were mild and easy to control, the modified level was higher than other chemical modification, and its modification effect was outstanding. In this study, yak milk caseins were selected as materials and succinylation was used to modify the yak casein, and the effect of succinylation on casein emulsification and hydrophobility was studied. The GRNN was also used to build the model of relationship between pH, succinylated level, the main parameters of caseins hydrophobility, emulsifying properties, and it was proved to have good predictability. The results showed that the emulsifying properties of protein were affected by pH, spacial conformation, and hydrophobility mainly, and they were non-linearly related. The emulsification and hydrophobility of yak caseins were influenced by the degree of succinylation and pH. Above a pH of 5, with the increase of degree of succinylation, emulsifying activity of caseins increased. Near the isoelectric point, emulsifying activity was poorer, and then increased rapidly with the increasing of pH. The emulsion stability of modified casein was stronger with pH between 2-6, which changed slowly with pH between 6-11, and then increased greatly with pH at 12, and the emulsion stability of 10 min increased obviously. The values of native and ANS fluorescence intensity and maximum emission wavelength of native and ANS fluorescence of modified casein showed a more complex relationship with succinylated degree and the pH. GRNN had a good performance in deal with complex relationships of non-linear, which was used to establish the relationship model between succinlated level, pH, vital parameters of hydrophobility, and emulsifying properties in order to predict the emulsifying activity and emulsion stability with 10 min and 30 min. The error of predicted values was within 10%, so the results of prediction were credible. The model would save time and the cost of test about studying and predicting yak caseins emulsifying properties. The results could provide references for the study on emulsification of yak caseins and succinylation caseins. [ABSTRACT FROM AUTHOR]