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Powder breakage during pneumatic conveying negatively affects the properties of dairy products and causes increased dusting, reduced wettability, and decreased product performance. In particular, particle breakage is a serious issue for fat-filled milk powder (FFMP) which, if it breaks, releases fat that causes odours and leads to sticky blocked pipes. In this work, a conveying rig (dilute phase, positive pressure) with 50 mm diameter food grade stainless steel pipes (1.5 m high and 5 m conveying distance with three 90° bends, two in the vertical plane and one in the horizontal plane) was built as the test system. The effects of operating conditions (conveying air velocity and solid loading rate) on the attrition of FFMP in a dilute phase conveying system were experimentally studied. Four quality characteristics were measured before and after conveying: bulk density, particle size distribution, wettability, and solubility, to access the influence of particle breakage. Conveying air speed shows a significant impact on powder breakage. As air speed increased, more breakage occurred, and the volume mean diameter D[4,3] decreased by around 50%, using the largest conveying air speed of 38 m/s. Bulk density increased accordingly whereas wettability decreased with an increase in air speed, resulting from the higher breakage rate. On other hand, improving the solid loading rate can further reduce the breakage level, but the positive effect is not as good as decreasing air speed.

In this study, cross-linked purple potato starch was prepared from purple potato starch and a mixture of sodium tripolyphosphate and sodium trimetaphosphate as crosslinking agent, aiming at studying the effect of different degrees of substitution (0.0053~0.0212) on cross-linked starch, determining and characterizing the properties of cross-linked purple potato starch with different degrees of substitution. The results showed that with the increase of degree of substitution, the cross-linked purple potato starch of transparency and solubility degree boosted, swelling degree decreased, and freezing-thaw stability increased. The surface of purple potato starch was intact and smooth, but the cross-linked purple potato starch presented a stripped-off appearance. The force of interparticle of cross-linked purple potato starch increased, and the adhesion and aggregation of cross-linked purple potato starch represented obviously. All the crystallization of samples was C-type, the average particle size of cross-linked purple potato starch was not significantly different compared with purple potato starch, but the crystallinity decreased with the increase of degree of substitution. The negative charge of cross-linked purple potato starch also increased with the increased degree of substitution. Therefore, the properties of cross-linked purple potato starch were greatly improved compared with purple potato starch and were closely associated with degree of substitution, which provided theoretical basis for the further development of purple potato resources.

Gallic acid–Antarctic krill peptides (GA-AKP) nanocapsules (GA-AKP-Ns) were prepared using a dual delivery system with complex emulsion as the technical method, a high-pressure microjet as the technical means, polylactic acid–hydroxyacetic acid (PLGA) as the drug delivery vehicle, and GA-AKP as the raw material for delivery. This study aimed to investigate the effects of microjet treatment and the concentration of PLGA on the physicochemical properties and stability of the emulsion. Under optimal conditions, the physicochemical properties and hypoglycemic function of nano-microcapsules prepared after lyophilization by the solvent evaporation method were analyzed. Through the microjet treatment, the particle size of the emulsion was reduced, the stability of the emulsion was improved, and the encapsulation rate of GA-AKP was increased. The PLGA at low concentrations decreased the particle size of the emulsion, while PLGA at high concentrations enhanced the encapsulation efficiency of the emulsion. Additionally, favorable results were obtained for emulsion preparation through high-pressure microjet treatment. After three treatment cycles with a PLGA concentration of 20 mg/mL and a microjet pressure of 150 MPa (manometric pressure), the emulsion displayed the smallest particle size (285.1 ± 3.0 nm), the highest encapsulation rates of GA (71.5%) and AKP (85.2%), and optimal physical stability. GA-AKP was uniformly embedded in capsules, which can be slowly released in in vitro environments, and effectively inhibited α-amylase, α-glucosidase, and DPP-IV at different storage temperatures. This study demonstrated that PLGA as a carrier combined with microjet technology can produce excellent microcapsules, especially nano-microcapsules, and these microcapsules effectively improve the bioavailability and effectiveness of bioactive ingredients.

With the increasing awareness of food safety among consumers, the visual judgment of food quality through packaging color change has become a new demand, therefore, smart packaging has become a common concern of academia and industry in recent years. pH-sensitive materials mixed with different polymers to obtain food packaging films that display different colors under different pH conditions have the real-time monitoring of the freshness of meat, shrimp, milk and other foods effect. This paper introduces two major pH-sensitive indicators, chemical chromophores and natural pigment chromophores, and classifies the color change mechanism of natural food pigments such as anthocyanin, curcumin, alizarin, cometin and betaine at different pH values, and summarizes the research progress, application status and research trends of pH-sensitive materials modified by blending with different polymers in the field of food packaging, in order to prepare a good performance, green and environmentally friendly. It provides a reference for the preparation of good performance and green food packaging.

This study aims to explore the formation mechanism of ethyl acetate and organic acids in acid rice soup (rice-acid soup) inoculated with Kluyveromyces marxianus L1-1 through the complementary analysis of transcriptome and proteome. The quantity of K. marxianus L1-1 varied significantly in the fermentation process of rice-acid soup and the first and third days were the two key turning points in the growth phase of K. marxianus L1-1. Importantly, the concentrations of ethyl acetate, ethanol, acetic acid, and L-lactic acid increased from day 1 to day 3. At least 4231 genes and 2937 proteins were identified and 610 differentially expressed proteins were annotated to 30 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways based on the analysis results of transcriptome and proteome. The key genes and proteins including up-regulated alcohol dehydrogenase family, alcohol O-acetyltransferase, acetyl-CoA C-acetyltransferase, acyl-coenzyme A thioester hydrolase, and down-regulated aldehyde dehydrogenase family were involved in glycolysis/gluconeogenesis pathways, starch and sucrose metabolism pathways, amino sugar and nucleotide sugar metabolism pathways, tricarboxylic acid (TCA) cycle, and pyruvate metabolism pathways, thus promoting the formation of ethyl acetate, organic acids, alcohols, and other esters. Our results revealed the formation mechanisms of ethyl acetate and organic acids in rice-acid soup inoculated with K. marxianus L1-1.

Deep knowledge of the microstructure and physicochemical properties of polymeric food systems, such as honey powders (HP) and coconut sugars (CS), has practical importance for industry and end users. This study investigated the effect of polyvinylpyrrolidone (PVP) addition on microstructure, roughness, glass transition, α-relaxation temperatures and structural strength (S) of anhydrous complex carbohydrates mixtures. The addition of PVP slightly increased the glass transition and α-relaxation temperature for HP and CS systems as high molecular weight components. Systems with PVP addition showed “stronger” behaviour according to the S approach. Polarized light, scanning electron and atomic force microscopies showed slight differences in transparency and shapes between controls and systems with PVP addition. Surface morphological changes and roughness were investigated in this study to provide insight into HP and CS particles’ structural changes. Moreover, S-involved structural diagrams were built to determine S parameters for controlling the structural transformation of HP and CS systems with and without PVP addition. The results obtained in this work provide new information on polymer-carbohydrate interactions in complex food systems and structural transformations during their production and storage.

In order to explore the effects of different drying methods on the functional characteristics and the internal mechanism of egg white protein (EWP), egg white protein powder was prepared by spray drying or vacuum freeze drying, respectively. The protein structure, physicochemical properties and functional properties of spray dried egg white powder (EWP-P) and freeze dried egg white powder (EWP-D) were studied. The results showed that compared with the liquid egg white (EWP-C), spray drying could greatly decrease the endogenous fluorescence intensity of EWP, while improve the surface hydrophobicity and free sulfhydryl group content. Fourier transform infrared spectroscopy showed that the α-helix, β-fold and β-turn of EWP-P were 16.30%, 25.72% and 40.23%, respectively, and EWP-D were 20.43%, 24.32% and 35.69%, respectively. Under different pH, the solubility of EWP-D was higher than EWP-P, and the surface tension was lower than EWP-P. In addition, the contact angle of EWP-P was 99.62°, which was higher than EWP-D (65.97°), indicating that spray drying could significantly improve the hydrophobicity of EWP. The emulsifying ability index, emulsifying stability index and foaming characteristic of EWP-D were higher than EWP-P at different pH values, but the foaming stability of EWP-D was lower. The results of fluorescence inverted microscope and confocal laser scanning microscope showed that the liquid droplets of EWP-D emulsion were smaller and more uniform, and the emulsion stability was higher than EWP-P. In conclusion, EWP-P had higher contents of β-fold structures and free sulfhydryl groups on the surface, and higher surface hydrophobicity, which resulted in the better gel properties. EWP-D had lower surface hydrophobicity, smaller surface tension and greater solubility, thus possessed the better emulsifying capacity and foaming characteristic.

Buckwheat protein isolate (BPI) was extracted from buckwheat (Fagopyrum esculentum Moench.) by alkali solubilization and acidic precipitation, following by spray-drying or vacuum freeze-drying to prepare protein powder. The effects of transglutaminase (TGase) and drying methods on physicochemical and gelling properties of buckwheat protein isolate were investigated. The results showed that the protein components of freeze-dried buckwheat protein isolate (FBPI) were similar to BPI, whereas the degradation of 13S globulin was observed in spray-dried buckwheat protein isolate (SBPI). The α-helix contents of FBPI and SBPI were 22.10% and 20.00%, with corresponding β-sheet contents of 19.40% and 19.80% respectively, indicating the transformation of disordered structure in BPI after spray-drying or vacuum freeze-drying. As compared with BPI, SBPI possessed the higher surface hydrophobicity and more uniform particle with a small size, but lower solubility and water holding capacity, while FBPI exhibited similar physicochemical properties to BPI. The average particle sizes of FBPI and SBPI increased from 213.01 and 192.55 nm to 2289.01 and 1439.67 nm after TGase addition respectively, which due to the intermolecular crosslinking reaction. The potentials of BPI, FBPI and SBPI were −15.93, −29.43 and −29.35 mV, respectively, suggesting that drying treatment could further improve the stability of protein solution. Compared with SBPI, G' of BPI and FBPI decreased continuously during the heating process, implied that the gel structures of BPI and FBPI could be destroyed by heating. After pretreatment by heating and then cooling down, FBPI showed a significantly (P

ABSTRACT: Particle breakage of dairy powders occurs easily during many processes, reducing the powder functionality. The characteristics of particles and the applied stress from processing conditions on the particles are 2 main factors that can be manipulated to reduce breakage. In this study, we explored the effect of whey protein and lactose contents on dynamic breakage in agglomerated whey protein-lactose powders to provide useful information, in terms of particle characteristics, for controlling unwanted dairy powder breakage. A series of model agglomerates with different whey protein:lactose ratios were produced under the same spray-drying conditions, through a pilot plant trial. We evaluated physical characteristics, composition, and structure of samples; analyzed dynamic breakage under different mechanical stresses; and investigated the rehydration and water adsorption properties of model powders before and after breakage. The particle size and irregularity of agglomerates with more lactose was significantly higher than of samples that contained more protein. This resulted in higher particle breakage during dynamic breakage for samples with more lactose. The breakage of agglomerates was affected by the moisture content of powders and fatigue, where particle breakage happens when mechanical loads, lower than the strength of particles, occur multiple times. Breakage changed the morphology and surface composition of particles and decreased particle size. It also decreased the dispersibility of powders and increased the wetting time of wettable samples but decreased the wetting time of powders with poor wettability. Breakage accelerated time-dependent crystallization and decreased the crystallization temperature but did not affect the glass transition temperature of samples. Thus, under the same drying conditions, composition of powders significantly affected breakage, mainly by altering the physical properties of their particles, which resulted in deteriorated functionality.

The dietary intervention has demonstrated effectiveness in improving hyperlipidemia and obesity. Woody edible oils are rich in unsaturated fatty acids (UFAs) that could positively affect lipid metabolism. In this study, the blended oil (BLO), a balanced UFA supplement, constituted by Zanthoxylum bungeanum (Chinese Red Pepper) seed oil, walnut (Juglans regia) oil, camellia (Camema oleifera) seed oil and perilla (Perilla frutescens) seed oil was established referring to the Chinese dietary reference intakes, in which the ratios of monounsaturated/polyunsaturated fatty acids and ω-6/ω-3 polyunsaturated fatty acids were 1:1 and 4:1, respectively. The BLO was administrated to KM mice fed a high-fat diet (HFD) by gavage every day at a dose of 3.0 mL/kg·bw for 10 weeks to assess its effects on serum lipid levels, liver antioxidant activities and gut microbial composition. The results showed that the BLO improved hepatic steatosis, liver oxidative stress, and serum lipid levels. Additionally, there was an increased abundance of Lactobacillus, Allobaculum, and Blautia, along with a decreased abundance of Staphylococcus in cecal contents. These changes were found to be positively correlated with the metabolic improvements, as indicated by Spearman’s correlation analysis. These findings implied the practicality of the balanced unsaturated fatty acid consumption in preventing hyperlipidemia and obesity.

The effects of different storage temperatures on the nutritional quality, color, and antioxidant capacity of lotus seed juice and the correlations between various physicochemical indices and antioxidant capacity during storage were investigated in this study. The results showed that the overall retention rate of various nutrients and antioxidant activity in lotus seed juice under low-temperature storage was better than that under 37 °C storage. Meanwhile, temperature had a significant effect on increasing the browning of lotus seed juice and the change in L*. The results of Pearson correlation and redundancy analysis (RDA) showed that the reduction in antioxidant activity in lotus seed juice aggravated the browning index of the system at high temperatures. The color changes in the system were closely related to the clarity of lotus seed juice and aging of starch at low temperatures.

The crystallization of lactose usually causes the structural collapse and core material escape of flavor encapsulations. The objective of this study was to investigate the effects of different grafting degrees of WPI-inulin Maillard reaction products on the lactose crystallization and the subsequent release behaviors. Ethyl acetate was chosen as the model volatile flavor and the encapsulations were prepared by freeze-drying. The results found that the encapsulation efficiency was significantly increased from 30% to over 80% by using MRPs as wall materials. Those microparticles showed the greater flavor retention and lower moisture adsorption. In addition, the encapsulations produced by the proper Maillard reaction times (e.g., 48 h and 72 h) could effectively delay the lactose crystallization and thus improve the structural stability of the matrix. This innovation finding aims to use the Maillard reaction to control the crystallization behaviors and enhance the usefulness of high-lactose containing products in encapsulation systems.

The search for alternative salt formulations similar to sodium chloride and their effect on marinated meat products is of great significance to the low-sodium meat processing industry. The main purpose of this study was to investigate the effect of partially replacing sodium chloride with potassium lactate, calcium ascorbate, and magnesium chloride on the sodium content, water activity and distribution, protein solubility, microstructure, sensory characteristics and volatile flavor compounds in low-sodium marinated beef. The sodium content in the test group decreased up to 28% compared to 100% in the sodium chloride group C1. The formulation including 60% sodium chloride and a total of 40% compound alternative salts in groups F1 and F2 increased their myofibril fragmentation index and promoted the disruption of the myogenic fiber structure. Group F1 (the ratio of potassium lactate, calcium ascorbate and magnesium chloride was 2:1:1) performed higher solubility of myofibrillar proteins and lower transverse relaxation value than group F2 detected by low-field nuclear magnetic resonance, which indicated that F1 formulation was beneficial to promote the solubility of myofibrillar proteins and attenuate the water mobility of marinated beef. Moreover, group F1 had a more similar microstructure and more similar overall sensory attributes to group C1 according to the scanning electron microscopy. The sensory evaluation showed higher peak intensity and response values of volatile flavor compounds than group C1 and C2 (only 60% sodium chloride) when detected using gas chromatography–ion mobility spectrometry technology, which indicated that the compound alternative salts of group F1 can improve the lower quality of low-sodium marinated beef and perform similar attributes to the C1 sample regarding moisture distribution and microstructure and even performs better than it with regards to flavor. Therefore, the F1 formula possessed greater potential for application in low-sodium marinated meat products.

Fish bone gelatins were prepared from Anguilla rostrata by acidic or alkali pretreatment combined with hot water extraction. The physicochemical properties and gel properties of fish bone gelatins were investigated via the yield determination, gel strength measurement, SDS-PAGE analysis, ultraviolet full-wavelength scanning, infrared spectrum scanning, dynamic rheology measurement and scanning electron microscopy. As results, the yields of acid pretreated gelatin (AG60) and alkaline pretreated gelatin (BG60) were 13.6% and 6.88%, with the corresponding gel strengths of 101.95 g and 78.74 g, respectively. The hydroxyproline contents of AG60 and BG60 were 3.2 g/100 g and 2.7 g/100 g. Both gelatins were mainly consisted of β and α1, α2 chains, the contents of α1 and α2 chains in AG60 was significantly higher than those in BG60. Both AG60 and BG60 possessed the characteristic absorption peak of gelatin without any absorption peaks for other proteins. The AG60 possessed higher gelling temperature and melting temperature, as well as a shorter gelling time. Scanning electron microscopy analysis showed that AG60 showed a more dense and uniform gel network structure as compared with BG60. Present study suggested that the eel bone gelatin prepared by acidic pretreatment had better gel properties than that of gelatin prepared by alkali pretreatment.