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Myofibrillar proteins (MPs), the most important proteins in muscle, play a vital role in the texture, flavor, sensory and consumer acceptance of final muscle-based food products. Over the past several decades, conjugation of carbohydrates to MPs via glycosylation is of particular interest due to the substantial enhancement in MPs characteristics. Studying the covalent interactions between carbohydrates and MPs under various processing conditions and molecular mechanisms by which carbohydrates affect the functionalities of MPs can introduce new perspectives for design and production of muscle-based foods. However, there is no insightful and comprehensive summary of the structural, physicochemical and functional characteristics changes of MPs induced by glycosylation modification and how these changes can be adopted to potentially promote the science-based development of tailor-made muscle foods. Based on this, the functionalities of MPs as well as their practical limiting issues are initially highlighted. A comprehensive overview of fabrication strategies is then introduced. Additionally, changes in the structural and functional properties of MPs regulated by glycosylation have also been carefully summarized. On this basis, the research limitations to be solved and our perspectives for the future development of muscle-based foods are put forward. [ABSTRACT FROM AUTHOR]

To compare the difference of non-volatile taste-active flavor components of different chicken breeds, four Chinese native yellow feather broilers including Langshan chicken, Chongren chicken, Luyuan chicken and Wenchang chicken were used in the experiment. The contents of free amino acids, 5'-nucleotides and minerals were determined by standard method, and then five principal components were extracted from the multi-index system based on the principal component analysis (PCA). Combined with the Mahalanobis distance analysis method and sensory evaluation results, the advantages and characteristics of each chicken breed were evaluated. The results showed that different kinds of chicken had their own advantages in different evaluation dimensions. The Equivalent umami concentration (ECU) of Wenchang chicken, which had the highest content of amino acids, was 12 g monosodium glutamate (MSG)/100 g, indicating the umami taste of it was very intense. The indexes of Langshan chicken were relatively uniform, with slightly higher mineral content, its overall Mahalanobis distance score was more similar to the "best standard". According to the Mahalanobis distance score, although the difference in amino acid content among each species was the largest, the overall score was more affected by the content of minerals and nucleotides, and there was interaction between each nutrient, which had an impact on the overall Mahalanobis distance score. The sensory evaluation results indicated that Wenchang chicken was the most superior among the taste of the four varieties investigated. Finally, taste compounds affecting the difference of chicken varieties were analyzed by partial least squares regression (PLS), resulting in order of mineral (Ca2+, Mg2+, PO43−) > nucleotide (AMP, IMP) > amino acid. This could provide a theoretical basis for quantitative oriented flavor processing and consumer choice of chicken. [ABSTRACT FROM AUTHOR]

As living standards rise, the demand for high-quality chilled meat among consumers also grows. Researchers and enterprises have been interested in ensuring the quality of chilled meat in all links of the downstream industry. Nanozyme has shown the potential to address the aforementioned requirements. Reasons and approaches for the application of nanozymes in the freshness assessment or shelf life extension of chilled meat were discussed. The challenges for applying these nanozymes to ensure the quality of chilled meat were also summarized. Finally, this review examined the safety, regulatory status, and consumer attitudes toward nanozymes. This review revealed that the freshness assessment of chilled meat is closely related to mimicking the enzyme activities of nanozymes, whereas the shelf life changes of chilled meat are mostly dependent on the photothermal activities and pseudophotodynamic activities of nanozymes. In contrast, studies regarding the shelf life of chilled meat are more challenging to develop, as excessive heat or reactive oxygen species impair its quality. Notably, meat contains a complex matrix composition that may interact with the nanozyme, reducing its effectiveness. Nanopollution and mass manufacturing are additional obstacles that must be overcome. Therefore, it is vital to choose suitable approaches to ensure meat quality. Furthermore, the safety of nanozymes in meat applications still needs careful consideration owing to their widespread usage. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of wooden breast (WB) myopathy on chemical composition, meat quality attributes and physiochemical characteristics of intramuscular connective tissue (IMCT) of broiler pectoralis major (PM) muscle. Thirty-six fillets were classified into varying degrees of WB condition, including normal, moderate and severe. Results show that WB myopathy altered the collagen profile in PM muscle by increasing total collagen content and decreasing collagen solubility. The composition of macromolecules in IMCT, including hydroxylysyl pyridoxine cross-linking, decorin and glycosaminoglycans, were increased with the severity of WB myopathy. Differential scanning calorimetry analysis indicated higher denaturation temperatures and lower denaturation enthalpy of IMCT for WB. Secondary structures of α-helix and β-sheet in the IMCT of WB were changed to β-turn and random coil. In addition, chemical composition and meat quality attributes showed a correlation with collagen profile and IMCT characteristics. Overall, this study emphasizes the effect of WB myopathy on IMCT and their contributions to meat quality variation. [ABSTRACT FROM AUTHOR]

This study focuses on analyzing the texture properties and bioelectrical impedance characteristics of frozen chicken breasts during low‐temperature thawing, meanwhile, we also compared the differences in physiochemical properties. Frozen chicken breasts were thawed at 4 ± 2°C for 2, 4, 6, 8, and 10 h separately, then the physiochemical properties (color, pH, water‐holding capacity, water distribution), the texture properties (easy‐to‐cut level), and the bioelectrical impedance were determined and analyzed. The easy‐to‐cut level of the samples was evaluated by the sensory panel and two indexes, one is Warner‐Bratzler shear force measured by texture analysis machine, and the other is cutting speed value calculated by the consumer‐oriented cutting behavior analysis using frame‐by‐frame video recording analysis method. These two methods were used to characterize the easy‐to‐cut level of the frozen samples during thawing from the industrial processing and home cooking standpoint. Strong correlations were observed between the easy‐to‐cut level and the bioelectrical impedance of the frozen chicken breasts during thawing. The impedance magnitude at 100 kHz showed a high correlation coefficient (R2 =.9417) with Warner‐Bratzler shear force, and the impedance magnitude at 50 Hz showed a high correlation coefficient (R2 =.8658) with cutting speed. Our results indicated the acceptability of using bioelectrical impedance to evaluate the easy‐to‐cut thawing endpoint for both industry processing and home cooking. [ABSTRACT FROM AUTHOR]

The impact of phytophenols on myofibrillar protein (MP) has attracted great interest, due to the advantageous effects of phytophenols on the quality of meat and meat products under differential oxidation scenarios. Under natural oxidation scenarios, phytophenols can not only preserve product from quality deterioration, but also strengthen textural and organoleptic properties by structural and functional modification of MP. Meanwhile, phytophenols as structural modifiers are deliberately applied in gelled muscle foods under artificial oxidant scenarios. To successfully realize the application of phytophenols in meat products, the impact of phytophenols on MP should be explored, and the application scenarios which were commonly neglected must be considered. Therefore, this review provided a scenario structured summary on the phenol-modified MP structure, functionality and the ultimate quality of muscle foods to underline this fact. Moreover, the innovation applications of MP−phytophenols interaction, such as structure formation of MP gelled foods, functional packaging material, protein valorization and functional MP colloids, were also introduced. This work can foster better understanding on MP−phytophenols interaction and its emerging applications. [ABSTRACT FROM AUTHOR]

The series of biochemical reactions, metabolic pathways, and regulatory interactions that occur during the storage of meat are the main causes of meat loss and waste. The volatile compounds produced by these reactions, such as hydrogen sulfide, acids, and amines, can directly indicate changes in the freshness of meat during storage and sales. In this study, a one-pot hydrothermal method based on a surface control strategy was used to develop nanoparticles of silver with different reactivities, which were further immobilized in agar powder to develop a colorimetric sensor array. Due to the different chemical interactions with various volatile compounds, the colorimetric sensor array exhibited distinct color changes. The study demonstrates significant differences between 12 different volatile compounds and provides a quantitative and visual method to reveal rich detection indicators. The colorimetric sensor array is an economical and practical multi-analyte identification method. It has many potential applications such as food packaging, anti-counterfeiting, health monitoring, environmental monitoring, and optical filters. [ABSTRACT FROM AUTHOR]

Wooden breast myopathy (WBM) is a meat abnormality affecting pectoralis majors (PMs) of fast-growing broiler chickens. WBM-affected PMs exhibited varied meat qualities with increasing WBM severity. Normal PMs (NOR), mild WBM-affected PMs (MIL), moderate WBM-affected PMs (MOD), and severe WBM-affected PMs (SEV) were selected as raw materials. The structure and organization of connective tissue and fibrillar collagen were investigated through immersing with sodium hydroxide solution, Masson trichrome staining, and using an electron microscope. The mechanical strength of intramuscular connective tissue was analyzed via the shear force of samples treated with sodium hydroxide solution. The thermal property and secondary structure of connective tissue were analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. The obtained connective tissue was dissolved in a sodium hydroxide solution for the evaluation of the physicochemical properties of proteins, including particle size, molecular weight, surface hydrophobicity, and intrinsic fluorescence. In particular, the particle size was measured using a zeta potential instrument. The molecular weight was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The surface hydrophobicity and intrinsic fluorescence were measured by spectroscopy technology. Histologically, macrophage infiltration, myodegeneration and necrosis, regeneration, fibrous connective tissue, and thickened perimysial connective tissue were observed in WBM-affected PMs, especially SEV with fibrosis, including blood vessels. Compared with NOR, WBM led to increased average diameter of the collagen fibrils in perimysial (36.61 nm of NOR to 69.73 nm of SEV) and endomysial (34.19 nm of NOR to 56.93 nm of SEV) layers. A significant increase (p < 0.05) was observed in the mechanical strength (2.05 N to 5.55 N) of fresh PMs and the thermal transition temperature (onset temperature (TO), 61.53 °C to 67.50 °C; maximum transition temperature (TM), 66.46 °C to 70.18 °C; termination temperature (TE), 77.20 °C to 80.88 °C) of connective tissue from NOR to SEV. Cooking decreased the mechanical strength, and MOD samples showed the highest mechanical strength (1.24 N, p < 0.05), followed by SEV (0.96 N), MIL (0.93 N), and NOR (0.72 N). For proteins in connective tissue, random coil (19.64% to 29.61%, p < 0.0001), particle size (p < 0.05), and surface hydrophobicity (p < 0.05) increased with the decrease in the α-helix (14.61% to 11.54%, p < 0.0001), β-sheet (45.71% to 32.80%, p < 0.0001), and intrinsic fluorescence of proteins from NOR to SEV. The molecular weights of intramuscular connective tissue proteins were in the ranges of >270 kDa, 180–270 kDa, 110–180 kDa, 95–100 kDa, and <15 kDa. Taken together, WBM resulted in thickened organization, tightly packed collagen fibrils, increased mechanical strength and thermal temperature, and increased particle size, surface hydrophobicity, and intrinsic fluorescence of proteins in connective tissue, as the WBM severity increased. [ABSTRACT FROM AUTHOR]

Sanguinarine (1) is a natural product with significant pharmacological effects. However, the application of sanguinarine has been limited due to its toxic side effects and a lack of clarity regarding its molecular mechanisms. To reduce the toxic side effects of sanguinarine, its cyanide derivative (1a) was first designed and synthesized in our previous research. In this study, we confirmed that 1a presents lower toxicity than sanguinarine but shows comparable anti-leukemia activity. Further biological studies using RNA-seq, lentiviral transfection, Western blotting, and flow cytometry analysis first revealed that both compounds 1 and 1a inhibited the proliferation and induced the apoptosis of leukemic cells by regulating the transcription of c-MET and then suppressing downstream pathways, including the MAPK, PI3K/AKT and JAK/STAT pathways. Collectively, the data indicate that 1a, as a potential anti-leukemia lead compound regulating c-MET transcription, exhibits better safety than 1 while maintaining cytostatic activity through the same mechanism as 1. [ABSTRACT FROM AUTHOR]

Endogenous proteases are significant for Jinhua ham quality. Protein degradation affects the chemical traits, texture and the formation of flavor substances. Protease activities are affected by different process parameters, such as processing temperature, maturation time, salt content and the drying rate. They affect ham quality, which can be controlled by process parameters. The influences of key factors on Jinhua ham quality are briefly summarized, which can provide a theoretical basis for the selection of specific parameters in dry-cured ham processing. Furthermore, some suggestions are proposed for correcting and improving the flavor and textural defects of ham, yet the effectiveness depends on the operating conditions. The determination of enzyme activity is not real-time and unsupervised at the moment. Future research will focus on the determination of the actual endogenous protease activity and the quantitative relationship between the enzyme activity and main processing parameters. [ABSTRACT FROM AUTHOR]

BACKGROUND: Novel thermo‐reversible hydrogels that undergo gelation in feedback to external stimuli have numerous applications in the food, biomedical, and functional materials fields. Muscle myofibrillar protein (MP) has long been known for thermally irreversible gelation. Once the reversible gelation of MP is achieved, its scope for research and application will expand. RESULTS: The work reported here achieved, for the first time, a thermo‐reversible MP gelation by elaborate deamidation using protein glutaminase (PG). The protein concentration and PG reaction time within windows of 1.0–2.5% and 8 h or 12 h were observed to be vital for creating thermo‐reversible gels. The gel strength increased with protein concentration. The gel displayed a perforated lamellar microstructure, which resulted in a high water‐holding capacity. The rheological results revealed the thermo‐reversibility of the gel was robust for up to five cycles of heating and cooling. The thermally reversible gelation is closely related to the reversible assembly between individual α‐helix and helical coiled coil. Hydrophobic interactions proved to be predominantly involved in the formation and stabilization of the gel network structure. CONCLUSION: This work increases the scope of research into the thermo‐responsive behavior of MP‐based gel. It can foster advances in research into the applications of muscle proteins and into the use of PG as a novel ingredient in the food industry. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Myosin is the most important component of myofibrillar protein, with excellent gelling properties. To date, heating treatment remains the mainstream method for forming gel in meat products, and it has the most extensive application in the field of meat industry. However, at present, there are few reports on the effects of heating rates on myosin self‐assembly and aggregation behavior during heating treatment. RESULTS: The present study aimed to investigate the effects of different heating rates (1, 2, 3 and 5 °C min−1) on the self‐assembly behavior, physicochemical, structural and gelling properties of myosin. At the lowest heating rate of 1 °C min−1, the myosin gel had a dense microstructure, the highest elastic modulus (G′) and water holding capacity compared to higher heating rates (2, 3 and 5 °C min−1). At higher temperatures (40, 45 °C), the surface hydrophobicity, turbidity, particle size distribution and self‐assembly behavior of myosin in pre‐gelling solutions showed that myosin had sufficient time to denature, underwent full structure unfolding before aggregation at the heating rate of 1°C min−1, and formed regular and homogeneous spherical aggregates. Therefore, the myosin gel also had a better three‐dimensional network. CONCLUSION: The heating rates had an important effect on the quality of myosin gels, and had theoretical implications for improving the quality of meat gel products. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Herein, we design and prepare large-area silver nanoparticle (Ag NP) films based on evaporation-induced self-assembly, which offers the visual and real-time detection of chilled broiler meat freshness. The color change is based on the fact that an increase in the biogenic amine (BA) concentration causes a change in the absorption wavelength of Ag NPs caused by aggregation and etch of the Ag NPs, resulting in a yellow to brown color change, thus enabling a naked-eye readout of the BA exposure. The Ag NP films exhibit a rapid, sensitive, and linear response to BAs in a wide detection range of 2 µM to 100 µM. The Ag NP films are successfully applied as a quick-response, online, high-contrasting colorimetric sensor for visual detection of the freshness of chilled broiler meat. [ABSTRACT FROM AUTHOR]

In this study, carnosine (0‒0.20%, w/v) was introduced to improve the dispersibility of myosin under a low-salt condition (0.1 M NaCl). The underlying dispersion mechanism was investigated. Carnosine has positive effects on the dispersibility of myosin, as evidenced by the significantly improved solubility and turbidity. After the addition of carnosine, the average particle size in each sample remarkably decreased, and the mole mass of the aggregates decreased from 6.74 × 107 g/mol to 4.00 × 107 g/mol as the carnosine increased from 0.10 to 0.20%. Changes in protein secondary structure, ζ-potential, and ITC (Isothermal titration calorimetry) results indicated that electrostatic interaction is the main force between myosin and carnosine. Moreover, carnosine may hinder the formation of large aggregates by affecting the structure and charge distribution of the myosin tail when carnosine was ≤ 0.10%. However, excess carnosine (˃ 0.10%) had a negative effect on the long-term stability of the protein solution. Turbiscan stability index, visual appearance, and hydrophobicity analyses showed that the instability of the system was possibly due to increase in the hydrophobicity of myosin head after excess carnosine was applied. Our research may contribute to the improvement of the functional properties of myosin under low-salt condition and regulation of protein behavior. [ABSTRACT FROM AUTHOR]

Summary: Excessive bitterness is a common problem and is related to the hydrolysis of structural proteins degradation in the dry‐cured ham industry. To better understand the effect of structural proteins (myosin, titin, troponin) degradation on sensory development of Jinhua ham, sensory attributes, exopeptidase activities, peptide fragments and cleavage sites of structural proteins were investigated in both premium and defective hams. The results of sensory evaluation and electronic tongue revealed that more than 1.5‐fold values in bitterness intensities and less than 0.67‐fold values in richness intensities were observed in defective ham, compared with premium ham. The activities of exopeptidase were determined, and the results indicated that the residual activities of TPP I in defective ham were higher, while the residual activities of LAP and AAP were lower, compared with premium ham. The large numbers of unique peptide fragments derived from myosin, titin and troponin were identified in defective ham. Several unique cleavage sites including L‐399, L‐1047 and K‐1053 for MYH 1 and MYH 4, K‐257, R‐694, K‐1374 and K‐1651 for MYH 7, and K‐92 and K‐103 for TNN C1 and TNN C2 were only presented in defective ham, which were intensely response to the excessive accumulation of peptides and the development of excessive bitterness in defective ham. This study could provide a theoretical basis for the regulation of bitterness defects in dry‐cured ham in the future. [ABSTRACT FROM AUTHOR]

Goose liver isolate treated by pH shifting and pH shifting/non-enzyme phosphorylation with goose liver isolate was used as a control. The functional property differences in the protein and proteins involved in the interfacial layer treated with pH shifting and non-enzyme phosphorylation were studied. Compared with the goose protein isolates (GPIs) at pH 7.0, the GPIs treated by pH shifting was not a good choice to be an emulsifier in a neutral environment, and non-enzyme phosphorylation inhibited the negative effects of pH shifting treatment and improved protein properties. The results of proteomics showed that the identified proteins in the interfacial layer belong to hydrophilic proteins. Non-enzyme phosphorylation increased the abundances of most proteins due to ion strength, including some phosphorylated proteins. Correlation analysis indicated that protein solubility was highly positively related with S0, intrinsic fluorescence, total sulfhydryl, free sulfhydryl, A0A0K1R5T3, R0KA48, R0KFP7, U3J1L1, P01989, R0JSM9, and R0LAD1, and was also highly negatively related with particle size and R0M210, R0M714, and R0LFA3. The emulsifying activity index (EAI) demonstrated highly positive correlation with protein solubility, and was correlated with R0JKI4, R0KK84, R0L1Y3, R0LCM7, A0A068C605, and U3IW62. [ABSTRACT FROM AUTHOR]

In addition, oral Gln supplementation induces HSP70 protein expression, thereby attenuating oxidative stress and inflammatory responses and alleviating skeletal-muscle protein degradation in rat models of muscle disuse [[17]]. Levels of HSP70 Compared with the CON group, the mRNA expression of HSP70 was significantly increased ( I p i < 0.05) in the PM muscles of broilers in the T and TG groups (Figure 1A), whereas the protein content of HSP70 was only increased ( I p i < 0.05) in the TG group (Figure 1B,C). Our previous study has demonstrated that the protein content of HSP70 is significantly decreased in the acute stress-induced PSE-like muscles of broilers and has reported high correlations between HSP70, and meat quality and stress indicators [[13]], suggesting a potential role of HSP70 in chicken-meat-quality development. [Extracted from the article]

The effects of whey protein hydrolysates (WPH) on myofibrillar protein (MP) oxidative stability and the aggregation behavior and the water-holding capacity of pork patties during freeze–thaw (F–T) cycles were investigated. During F–T cycles, the total sulfhydryl content and zeta potential of MP decreased, while peroxide value, surface hydrophobicity, particle size, pressure loss and transverse relaxation times increase. The oxidative stability and the water-holding capacity of pork patties were enhanced by the addition of WPH in a dose-dependent manner, whereas the MP aggregation decreased. The addition of 15% WPH had the most obvious effects on the pork patties, which was similar to that of the 0.02% BHA. After nine F–T cycles, the POV, surface hydrophobicity, particle size and pressure loss of the pork patties with 15% WPH were reduced by 17.20%, 30.56%, 34.67% and 13.96%, respectively, while total sulfhydryl content and absolute value of zeta potential increased by 69.62% and 146.14%, respectively. The results showed that adding 15% WPH to pork patties can be an effective method to inhibit lipid and protein oxidation, reducing protein aggregation and improving the water-holding capacity of pork patties during F–T cycles. [ABSTRACT FROM AUTHOR]

There is an increasing interest in the development of high internal phase emulsions (HIPE) stabilized by food-grade nanoparticles due to their potential applications in the food industry. In this study, cross-linked egg white protein isolates (cEPIs) are prepared by adding 10 u/g, 20 u/g, and 40 u/g of transglutaminase (TG), and the impacts of interface properties of cEPIs and emulsifying of HIPEs are investigated. Relative to the native EPI, the cEPIs have more irregular and agglomerated morphology, and the turbidity and hydrophobicity are significantly increased. The particle size and zeta potential of cEPIs considerably varied with the addition of TG. In HIPE, the formation, physical properties, and microstructure are characterized by visual observations, the Turbiscan stability index, and CLSM. The results indicated that stable and gel-like HIPEs are formed by cEPIs at oil internal phase (φ) values of 0.75–0.90. Especially for the enzyme additions of 20 u/g, the cEPIs had the best storage stability and the lowest TSI value (2.50) and formed a gel network structure at φ values of 0.9 microscopically. Overall, this study can enrich the theoretical frame of interface properties by enzyme treatment. Besides, it would be of great importance for the research of HIPE stabilized by cEPIs appropriate to be applied in food formulations. [ABSTRACT FROM AUTHOR]

Thirty-three benzophenanthridine alkaloid derivatives (1a–1u and 2a–2l) were synthesized, and their cytotoxic activities against two leukemia cell lines (Jurkat Clone E6-1 and THP-1) were evaluated in vitro using a Cell Counting Kit-8 (CCK-8) assay. Nine of these derivatives (1i–l, 2a, and 2i–l) with IC50 values in the range of 0.18–7.94 μM showed significant inhibitory effects on the proliferation of both cancer cell lines. Analysis of the primary structure–activity relationships revealed that different substituent groups at the C-6 position might have an effect on the antileukemia activity of the corresponding compounds. In addition, the groups at the C-7 and C-8 positions could influence the antileukemia activity. Among these compounds, 2j showed the strongest in vitro antiproliferative activity against Jurkat Clone E6-1 and THP-1 cells with good IC50 values (0.52 ± 0.03 μM and 0.48 ± 0.03 μM, respectively), slightly induced apoptosis, and arrested the cell-cycle, all of which suggests that compound 2j may represent a potentially useful start point to undergo further optimization toward a lead compound. [ABSTRACT FROM AUTHOR]

Monitoring food quality throughout the food supply chain is critical to ensuring global food safety and minimizing food losses. Here we find that simply by mixing an aqueous solution of sugar-stabilized Ag+ and amines in an open vessel leads to the generation of Ag NPs and an intelligent evaluation system based on a colorimetric Ag+ probe is developed for real-time visual monitoring of food freshness. The self-assembly reaction between methylamine (MA) generated during meat storage and the colorimetric Ag+ probe produces different color changes that indicate changes in the quality of the meat. The colorimetric Ag+ probe was integrated into food packaging systems for real-time monitoring of chilled broiler meat freshness. The proposed evaluation system provides a versatile approach for detecting biogenic amines and monitoring chilled broiler meat freshness and it has the advantages of high selectivity, real-time and on-site measurements, sensitivity, economy, and safety and holds great public health significance. [ABSTRACT FROM AUTHOR]

Intake of protein‐rich foods might induce oxidative stress in organs. This study investigated the impacts of protein sources including casein, soybean, fish, chicken, pork, and beef proteins on hepatic oxidation and antioxidation status in rats. It was shown that meat proteins produced higher reactive oxygen species in livers (from 64,868 to 87,153 F/mgpro) than casein (54,045 F/mgpro) and soybean protein (48,361 F/mgpro, p <.05). Pork and soybean proteins induced higher hepatic oxidative stress than fish, chicken and beef proteins by increasing malondialdehyde production (>16%, p <.05). White meat (fish and chicken) proteins promoted hepatic superoxide dismutase activity and total antioxidant capacity compared to soybean and red meat (pork and beef) proteins (p <.05). Compared to red meat proteins, white meat proteins increased hepatic expressions of thioredoxin and glutaredoxin. Rats fed red meat proteins showed hepatic steatosis with small vacuoles. Therefore, white meat proteins were more conducive to hepatic antioxidative status than soybean and red meat proteins. Practical applications: Intake of protein‐rich foods may induce oxidative stress response at both cell and organ levels. The objective of this study was to investigate the impacts of different protein sources including casein, soybean, fish, chicken, pork, and beef proteins on oxidation and antioxidation status in rat livers. It was shown that meat proteins induced higher production of reactive oxygen species than casein and soybean protein. However, white meat proteins showed higher antioxidant capacity than soybean and red meat proteins by increasing hepatic superoxide dismutase activity and total antioxidant capacity. Therefore, compared to soybean and red meat proteins, white meat proteins lowered hepatic oxidative stress by reducing malondialdehyde production. This study suggested that intake of moderate white meat proteins was more conducive to hepatic antioxidative status than intake of soybean and red meat proteins. This study would promote the understanding of healthy effects of different protein sources. [ABSTRACT FROM AUTHOR]

Sodium hypochlorite (NaClO) has been widely used at 100 ppm concentration during poultry slaughter to reduce carcass microorganism loads. However, its use in poultry processing is restricted owing to the potential risks of disinfection by‐products (DBPs) that can be produced by the reaction of NaClO with poultry meat components. This study assessed whether dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), as primary DBP representatives, were produced when NaClO was used as a disinfectant in various methods during broiler prechilling. Headspace gas chromatography‐mass spectrometry for the quantitative determination of DCAA and TCAA in 180 prechilling water samples and 30 broiler meat samples, obtained from large standard slaughterhouses equipped with an online monitoring system to control the NaClO concentration between 50 and 100 ppm, showed that neither DCAA nor TCAA were detected. In simulation assays, haloacetic acids (HAAs) were not detected when the concentration of the NaClO solution was less than 200 ppm with low frequency addition; however, more than 0.1 mg/L of DCAA and TCAA were detected on applying 200, 300, 400, 500, and 1000 ppm NaClO at high frequency. These findings indicated that adding high concentrations of NaClO and frequently adding low levels pose a potential risk of DBP formation. This investigation provides a basis for the establishment of food risk and the scientific use of NaClO in poultry processing, and contributes to the evaluation of DBPs in poultry slaughter. Practical Application: This study confirmed the occurrences of DCAA and TCAA during broiler chilling processing, indicating that formation of HAAs in simulation systems was correlated with NaClO levels and validated the absence of DCAA and TCAA with less than 200 ppm, providing a basic study for food safety standards and regulations on the disinfectants used in food processing. [ABSTRACT FROM AUTHOR]

Summary: Wooden breast myopathy affects the quality of fresh and processed chicken breast muscle. The objective of this study was to construct a classification method by instrumental stress, and the effects of wooden breast myopathy on meat quality and oral processing property, and was to explore correlations between stress and oral processing parameters. The severity of wooden breast myopathy was highly correlated to fillet weight (R2 = 0.740), thickness (R2 = 0.826) and hardness (R2 = 0.803) (P < 0.01). The 3D scatter model based on stress is robust and reliable to classify the fillets into four categories (normal, mild, moderate and severe wooden breast fillets), avoiding manual grading. Moisture, fat, collagen, pH, drip loss, cooking loss, thawing loss, purge loss, hardness, gumminess and chewiness significantly increased with the severity of wooden breast myopathy, whereas fat, ash and water/salt‐soluble protein contents significantly decreased (P < 0.05). Shear force reached the maximum (36.32 N) when this myopathy was moderate. The myopathy led to an increase in masseter activity and the particle size of the bolus. Significantly higher correlations between stress, Dx(50) (R2 = 0.790), Dx(90) (R2 = 0.771) and D[4,3] (R2 = 0.797) were found (P < 0.01). This study also showed that jaw movement and muscle activity could be used to understand the links between physical property and orally sensory property. [ABSTRACT FROM AUTHOR]

The environment in poultry abattoirs is the primary potential source of bacterial contamination and cross‐contamination of broiler carcasses. In this context, we explored the influence of chilling water and contact surfaces on the microbial diversity of broiler carcasses in warm and cold seasons. High‐throughput sequencing was used to target the V3‐V4 region of the 16S rRNA gene. Proteobacteria was the main phylum detected in broiler carcasses and on contact surfaces, whereas Bacteroidetes and Firmicutes had high abundances of the prechilling water in both seasons. At the genus level, Psychrobacter and Acinetobacter were much more abundant on broiler carcasses in the warm season, while Flavobacterium and Psychrobacter dominated in the cold season. LEfSe analysis showed that the chilling tank was a key location where carcass contamination occurred. Therefore, the risk of carcass contamination can be reduced by improving sanitary conditions during processing, installing longer chilling tanks, or increasing the water exchange rate in chilling tanks. The results of this study may be useful for better slaughterhouse environmental hygiene management in different seasons. Practical Application: This study will help poultry processing managers better understand the impact of different seasons on the environmental microbiota in the environment and their abundance in poultry processing plants, thus allowing them to adopt proper disinfection strategies for different seasons and environments, further improving the safety and shelf life of products. [ABSTRACT FROM AUTHOR]

In the present study, the synergetic effect and mechanism of ultrasound (US) and slightly acidic electrolyzed water (SAEW) on the inactivation of Escherichia coli (E. coli) were evaluated. The results showed that US combined with SAEW treatment showed higher sanitizing efficacy for reducing E. coli than US and SAEW alone treatment. US and US combined with SAEW treatments resulted in smaller particle size of E. coli compared to the control and SAEW treatment. In addition, US combined with SAEW treatment induced the highest potassium leakage. However, the highest protein leakage was recorded in US treatment. Moreover, scanning and transmission electron microscopy analysis revealed that the greatest damage of the appearance and ultrastructure of E. coli was achieved after US combined with SAEW treatment. The synergetic effect was also confirmed by CLSM analysis. Fluorescence spectroscopy suggested that treatments of US, SAEW, and US combined with SAEW changed protein conformation of E. coli. Overall, the present study demonstrated that the sterilization mechanism of US combined with SAEW treatment was decreasing the particle size and disrupting the permeability of cell membrane and the cytoplasmic ultrastructure as well as changing protein conformation of E. coli. [ABSTRACT FROM AUTHOR]

Background: Wooden breast (WB) myopathy in broiler chickens is a growing challenge for the poultry industry. Previous multi‐omic data have implied that the pathogenesis of WB is associated with the activation of immune system and inflammatory response. However, the intricate mechanisms are not fully understood. This study was therefore conducted to systematically investigate the morphology, expression of cytokines as well as the underlying signaling pathways regulating the inflammatory response in pectoralis major (PM) muscle of WB myopathic broilers. Results: wHistopathological changes, increased plasma creatine kinase and lactate dehydrogenase activities, elevated myeloperoxidase activity and overproduction of nitric oxide in muscle indicated the enhancement of muscle damage and inflammation in WB broilers. The messenger RNA (mRNA) expressions of inflammatory cytokines were dysregulated in PM muscle and contents of interleukin (IL)‐1β, IL‐8 and tumor necrosis factor‐α were increased in serum of WB myopathic broilers, indicating this myopathy was associated with immune disorder and systemic inflammation response. Additionally, toll‐like receptor (TLR) levels were upregulated, the nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) signaling pathway was activated and the mRNA expression levels of downstream inflammatory mediators were enhanced in PM muscle of WB myopathy affected birds. Conclusion: The results indicated an immune disorder and a systemic inflammation response in WB myopathic broilers, which might be related to a synergetic effect of TLRs and NF‐κB pathway. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

To improve the quality of meat products is a constant focus for both the meat industry and scientists. As major components in meat protein, the gelation properties of myofibrillar proteins (MPs) predominantly determine the sensory quality and product yield of the final product. Naturally or artificially occurring covalent modifications are known to largely affect MP functionality by changing the protein structure and forming aggregates, leading to both favorable and unfavorable outcomes. The review aims to summarize the mechanisms associated with several covalent modifications and the recent developments in enhancing MP gelation properties. Various extrinsic and intrinsic parameters controlling oxidation, phenolic–protein interactions, enzyme catalysis, glycation, and isoelectric solubilization/precipitation, and their effects on the characteristics of heat‐induced MP gels are discussed. This article provides an improved understanding of the covalent modifications that occur mainly in the MP system and how they can be utilized to promote its gelation properties. Covalent modifications exhibited dose‐dependent and dual‐role manners for MP gelation properties. Mild oxidation, enzyme catalysis, and isoelectric solubilization/precipitation treatment would be beneficial to form more aligned and cross‐linked three‐dimensional networks for MP gels because of moderate protein aggregation. However, an excessive aggregate impedes the MP gelation behavior, leading to reduced gelation quality. Glycation effectively increased hydrophilicity of MPs and phenolic conjugation provides MPs with novel bioactivity. A proper utilization of such a process or even a rational combination of them allowed us to enhance the gelation properties of MP with assorted appreciated functionalities and further improve the quality of meat products. [ABSTRACT FROM AUTHOR]

Today, both consumers and food industry producers have exhibited an ever‐growing interest in improving and broadening the functional performance of proteins in food industry. Myofibrillar protein (MP) is mainly responsible for texture, yield and organoleptic characteristics of final meat products. To increase functional properties of MP, technological and nutritional improvement of MP is needed to modify its structure and functionalities. Considerable approaches, including additives, oxidation treatments, and novel food processing technologies, have been utilized to modify its functional properties to manufacture acceptable meat products with lower cost and more desirable nutritional characteristics. However, a comprehensive summary of structural and functional changes of MP in response to different modification strategies is still lacking. Hence, in this review paper, our main goal is first to provide an overview of the functional characteristics of MP. Then, this review will mainly discuss the current knowledge on the functional changes of MP caused by various modification methods and will present some examples of previous works and recent progress. Finally, future outlooks are presented to tailor the manufacture of functionality enhanced and value‐added muscle‐based products and enable modified MP can be applied as a novel meat ingredient in food industry. [ABSTRACT FROM AUTHOR]

The differences of emulsion properties between normal colour chicken livers (NCCLs) and discolouration chicken livers (DCCLs) were evaluated. Compared with NCCLs, the L* and b*-value of DCCLs were extremely higher (p <.05), but the a*-value, cooking loss and emulsification stability were lower (p <.05). The elasticity and cohesiveness of two kinds of livers had significant difference (p <.05) after 45 °C. The particle size and optical morphology of the emulsion prepared with NCCLs were significantly smaller than that of the emulsion prepared with DCCLs (p <.05), and the emulsion of NCCLs was stable and uniform distribution. Overall, the NCCLs presented more stable emulsification properties than DCCLs, and the formed emulsion was exquisite and uniform. The results indicated that in order to obtain high quality emulsified chicken liver products, it might be necessary to select the NCCLs instead of DCCLs as raw material to process. The NCCLs could be great feasible and potential application in the development of emulsified chicken liver paste products. NCCLs had better emulsifying stability, cohesiveness and elasticity than DCCLs. Emulsion prepared with NCCLs presented stable and uniform distribution. NCCLs could be feasible to develop emulsified chicken liver paste products. [ABSTRACT FROM AUTHOR]

The incidence of pale, soft, and exudative (PSE)-like chicken meat is high worldwide. PSE-like chicken meat seriously affects the sensory qualities of fresh meat, which can decrease the consumer's purchasing desire, reduce chicken meat functionality, and decrease product yield, resulting in extensive economic losses for the poultry processing industry. This meat defect has been of increasing concern to processors and researchers in the poultry processing industry. The processing properties of PSE-like meat and the methods for improving its processing properties or alleviating its reduced functionalities are reviewed in the present article, with the aim of providing a theoretical basis and technical support for poultry processing to increase the practical value of PSE-like chicken meat. [ABSTRACT FROM AUTHOR]

In order to commercialize soft‐boiled chicken, a traditional Asian food, this work was performed to evaluate the effect of the packages on the edible quality. Soft‐boiled chickens were packaged with air packaging (AP) or modified atmosphere packaging (MAP, MN:100% N2 and MC:30%CO2/70%N2) conditions. Total viable counts reached the acceptable limit of 4.90 Log CFU/g at 1.5, 2.5, and 4 days of storage under AP, MN, and MC, respectively. However, sensory acceptance limits, based on overall acceptance by the professional panelists, were not reached until one day later. The TVB‐N content of MAP was lower than that of the AP. The finding indicated that the shelf life of soft‐boiled chicken could be extended by two days using MAP with CO2. These findings will provide basic reference for the packaging of cooked meat and also provide information on poultry processing techniques that could be applied at commercial scales. [ABSTRACT FROM AUTHOR]

Salmonella can resist various stresses and survive during food processing, storage, and distribution, resulting in potential health risks to consumers. Therefore, evaluation of bacterial survival profiles under various environmental stresses is necessary. In this study, the resistance profiles of five Salmonella isolates [serotypes with Agona, Infantis, Typhimurium, Enteritidis, and a standard strain (ATCC 13076, Enteritidis serotype)] to acidic, hyperosmotic, and oxidative stresses were examined, and the relative expressions of non-coding small RNAs were also evaluated, including CyaR , MicC , MicA , InvR , RybB , and DsrA , induced by specific stresses. The results indicated that although all tested strains displayed a certain resistance to stresses, there was great diversity in stress resistance among the strains. According to the reduction numbers of cells exposed to stress for 3 h, S. Enteritidis showed the highest resistance to acidic and hyperosmotic stresses, whereas ATCC 13076 showed the greatest resistance to oxidative stress, with less than 0.1 Log CFU/ml of cell reduction. Greater resistance of cells to acidic, hyperosmotic, and oxidative stresses was observed within 1 h, after 2 h, and from 1 to 2 h, respectively. The relative expression of sRNAs depended on the isolate for each stress; acidic exposure for the tested isolates induced high expression levels of DsrA , MicC , InvR , RybB , MicA , and CyaR. The sRNA RybB , associated with sigma E and outer membrane protein in bacteria, showed a fold change of greater than 7 in S. Enteritidis exposed to the tested stresses. CyaR and InvR involved in general stress responses and stress adaptation were also induced to show high expression levels of Salmonella exposed to hyperosmotic stress. Overall, these findings demonstrated that the behaviors of Salmonella under specific stresses varied according to strain and were likely not related to other profiles. The finding also provided insights into the survival of Salmonella subjected to short-term stresses and for controlling Salmonella in the food industry. [ABSTRACT FROM AUTHOR]

The aims of this work were to determine the physical characteristics (including color and texture profiles), compositions (including moisture, protein, fat, NaCl and pH) and volatile profiles of Chinese dry-cured hams (Mianning, Nuodeng, Saba and Sanchuan dry-cured hams) from different regions and explore the potential relationships in the above-mentioned parameters. Conventional physical and chemical analysis partially revealed differences among hams but were unable to discriminate them. Gas chromatography–time-of-flight mass spectrometry (GC–TOFMS) and electronic nose analysis provided an alternative. A total of 182 volatile compounds were detected by GC–TOFMS. With principal component analysis, the specific dominant volatiles were identified [ethanol, 3-methyl-3-buten-1-ol, 1-octen-3-ol, 1-octanol, hexanal, heptanal (E)-2-octenal, benzeneacetaldehyde, 3-ethyl-benzaldehyde, butanoic acid]. Electronic nose discriminated the hams because of the higher responses to ethanol and aldehyde. The results not only provide methods to discriminate the ham with different flavor profiles, but also represented the detailed information of Chinese dry-cured hams. [ABSTRACT FROM AUTHOR]

BACKGROUND: Heat treatment induces both structural and digestive change of meat protein. However, little has been revealed regarding the associations between structural changes and digested peptides of myofibrillar proteins. This work investigated the effects of heat treatment on the structures and in vitro digestibility of actomyosin, and the peptidomics of the digests were analyzed using liquid chromatography tandem mass spectrometry (LC–MS/MS). RESULTS: Heat treatment resulted in unfolding and aggregation behavior of actomyosin according to the results of surface hydrophobicity and particle size. Formation of disulfide bonds and increase in carbonyl groups that occurred during heat treatment of actomyosin indicated the oxidation of specific residues. Unfolding behavior could elevate digestibility of actomyosin by exposing residues, based on the identification of peptides in digests of actomyosin using LC–MS/MS. However, the disulfide bond proved to reduce the action of digestive proteases, since the peptides number (increased from 56 to 86 in sample heated at 70 °C for 30 min) and peptides intensity in digests largely increased after the addition of dithiothreitol (DTT). Heating at higher temperature (100 °C) induced severer aggregation and oxidation, which resulted in lower digestibility of actomyosin than that heated at 70 °C by burying or damaging partial cleavage sites for digestive proteases. CONCLUSIONS: This work highlights the huge influence of heat treatment on the multi‐scale structures of myofibrillar proteins, which largely changed the peptides composition in protein digests. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Casein and chicken are assessed to contain high quality proteins, which are essential for human health. Studies have shown that ingestion of the two dietary proteins resulted in distinct effects on physiology, liver transcriptome and gut microbiota. However, its underlying mechanism is not fully understood, in particular for a crosstalk between gut microbiota and host under a specific diet intervention. We fed young rats with a casein or a chicken protein-based diet (CHPD) for 7 days, and characterized cecal microbiota composition and cecal gene expression. We found that a short-term intervention with a casein-based diet (CAD) induced a higher relative abundance of beneficial bacterium Lactococcus lactis as well as Bifidobacterium pseudolongum , which upregulated galactose metabolism of the microbiome compared with a CHPD. The CAD also upregulated gene expression involved in obesity associated pathways (e.g., Adipoq and Irs1) in cecal tissue of rats. These genes and the bacterial taxon were reported to play an important role in protecting development of obesity. Furthermore, the differentially represented bacterial taxon L. lactis was positively associated with these differentially expressed genes in the gut tissue. Our results provide a new insight into the crosstalk between gut microbiota and host in response to dietary proteins, indicating a potential mechanism of obesity prevention function by casein. [ABSTRACT FROM AUTHOR]

This study was designed to determine the effects of µ/m‐calpain on the degradation of cytoskeletal proteins in pectoralis major. Four chickens were slaughtered and the breasts were removed and stored for 12 hr at 4 °C. Each sample was divided into three groups and respectively immersed in control reagent, calpain inhibitor, and caspase inhibitor at 4 °C. The samples were used to evaluate troponin‐T and desmin degradation, calpain activity, and myofibril ultrastructure at 12 hr, day 1, day 3, and day 7. Casein zymography revealed that µ‐calpain could not be detected in all samples after 12 hr postmortem. The calpain inhibitor inhibited µ/m‐calpain activity and reduced troponin‐T and desmin degradation during 7 day postmortem. The caspase inhibitor inhibited µ/m‐calpain activity and, troponin‐T and desmin degradation before day 3 postmortem. The findings suggest that, µ/m‐calpain had an effect on cytoskeletal protein degradation after 12 hr postmortem. [ABSTRACT FROM AUTHOR]

Summary: Porcine plasma protein (PPP) was used as encapsulation material based on its hydrophobic regulation through pH shifting, as follows: the exposed hydrophobic residues of PPP provide binding sites to curcumin at extreme alkaline pH value 12, and then, PPP–curcumin complex is formed by re‐adjusting the pH to a near neutral value. The stability and dispersibility of curcumin were significantly improved by this pH shifting method with PPP as carrier. The highest encapsulation efficiency (65.4%) of curcumin–PPP complex was obtained at 0.2 mg mL−1 curcumin concentration. The stability of curcumin–PPP complex improved with increasing ultimate pH value. The antioxidant activity of curcumin bound to the complex was comparable with that of native curcumin and did not get affected by heating at 121 °C for 1 min. Overall, a stable curcumin–PPP complex was formed by pH shifting method without organic solvents or specific equipment; this approach may considerably contribute to utilisation of PPP in the food industry. Curcumin can be successfully capsulated in PPP by pH 12 to 7 shifting method, evidenced by high encapsulation ratio, low turbidity and decreased fluorescence intensity. [ABSTRACT FROM AUTHOR]

Stress inevitably occurs from the farm to abattoir in modern livestock husbandry. The effects of stress on the behavioral and physiological status and ultimate meat quality have been well documented. However, reports on the mechanism of stress effects on physiological and biochemical changes and their consequent effects on meat quality attributes have been somewhat disjointed and limited. Furthermore, the causes of variability in meat quality traits among different animal species, muscle fibers within an animal, and even positions within a piece of meat in response to stress are still not entirely clear. This review 1st summarizes the primary stress factors, including heat stress, preslaughter handling stress, oxidative stress, and other stress factors affecting animal welfare; carcass quality; and eating quality. This review further delineates potential stress‐induced pathways or mediators, including AMP‐activated protein kinase‐mediated energy metabolism, crosstalk among calcium signaling pathways and reactive oxygen species, protein modification, apoptosis, calpain and cathepsin proteolytic systems, and heat shock proteins that exert effects that cause biochemical changes during the early postmortem period and affect the subsequent meat quality. To obtain meat of high quality, further studies are needed to unravel the intricate mechanisms involving the aforementioned signaling pathways or mediators and their crosstalk. [ABSTRACT FROM AUTHOR]

Soft‐boiled chicken is widely popular with its flavor and texture. In a traditional view, the edible quality of soft‐boiled chicken producing with hot‐fresh carcass (without any chilled procedure after evisceration) was better than that of chilled carcass. Hot‐fresh groups with 1, 2, or 4 hr and chilled groups with 24, 48, or 60 hr were used to clarify the view in this study. The results indicated that no significant difference in hardness, springiness, cohesiveness of texture profiles and b* value of skin color was observed between each group, although the highest L* value was obtained in hot‐fresh 4 hr group. Higher contents of succinic acid were found in chilled groups when compared to that of hot‐fresh groups, but there was no difference in lactic acid and pH values. Lower contents of adenosine 5′‐monophosphate (AMP), guanosine 5′‐monophosphate (GMP), inosine and hypoxanthine, and higher inosine‐5′‐monophosphate (IMP) (especially for hot‐fresh 1 hr) were observed in hot‐fresh groups. In addition, although no difference in umami amino acids and bitter amino acid was observed between each tested group, higher amounts of Asp, Met, Ile, Leu, Tyr, and Arg were observed in chilled groups, especially for chilled 60 hr. The finding indicated that the traditional view was lack of scientific evidence, and chilled carcass was suitable for soft‐boiled chicken, substituting for the hot‐fresh carcass. The finding indicated that the traditional view was a lack of scientific evidence, and chilled carcass was suitable for soft‐boiled chicken rather than hot‐fresh carcass. [ABSTRACT FROM AUTHOR]

The effects of chicken myofibrillar protein (MP) concentrations (20, 40 and 60 mg/mL) on MP oxidation and the subsequent effects on water holding capacity (WHC) of heat-induced gels were investigated. MP oxidation stressed by a hydroxyl radical-generating system (10 µM FeCl3, 0.1 mM ascorbic acid, and 1 mM H2O2) was evaluated by carbonyl content. Water distribution, microstructure visualization, free sulfhydryl (FSH) groups and molecular forces of the gels were determined to illustrate the effects on WHC. Compared to the non-stressed group, the stressed proteins were highly oxidized where the carbonyl content (p < 0.01) increased with decreasing MP concentrations (increased by 24.67% at 20 mg/mL). As the MP concentrations were decreased, the percentage of immobile water (decreased by 8.01% at 20 mg/mL, while increased by 5.98% at 60 mg/mL), ionic bonds, hydrogen bonds, and FSH groups (p < 0.05) of the oxidized gels were decreased, the gel network of the oxidized groups was impaired which was with more cracks and protein aggregates, the hydrophobic interactions (increased by 24% at 20 mg/mL) and the percentage of free water (p < 0.05) (increased by 7.80% at 20 mg/mL, but decreased by 6.13% at 60 mg/mL) of the oxidized gels were enhanced, and the resultant WHC was reduced (decreased by 17.75 and 8.07% at 20 and 40 mg/mL, respectively, but increased by 8.54% at 60 mg/mL). The results indicated that the MP concentration could be a potential influencing factor that affected the protein oxidation and subsequently affected the WHC of gels. [ABSTRACT FROM AUTHOR]

Soluble aggregates, instead of insoluble gel network, were formed on heat-treated chicken breast myosin through alkaline pH-induced electrostatic regulation. Heat treatment of myosin at pH 9.0 significantly increased solubility, decreased turbidity, and resulted in the highest content at 260 nm particle size compared with those at pH 7.0 and 8.0. Results indicated that soluble myosin aggregates were produced at pH 9.0. The surface hydrophobicity and reactive sulfhydryl (R-SH) of unheated sample revealed gradual increases with increased pH. This increase was related to the decreased α-helical, thereby suggesting myosin unfolding. After heating, treatment at pH 9.0 showed the lowest surface hydrophobicity and R-SH, which may contribute to the highest dispersibility. Moreover, heated myosin (pH 9.0) after reshifting pH still exhibited excellent stability, which indicated the irreversible soluble aggregates formation. The controlled production of aggregates may provide the possibility of using soluble aggregates as ingredients for expanded meat protein application in beverage products. [ABSTRACT FROM AUTHOR]

The texture, yield, and organoleptic properties of comminuted meat products are closely related to the structure and functionality of myofibrillar proteins (MP). To enhance functional properties of MP, high hydrostatic pressure (HHP) has been widely utilized to modify the structure of MP through protein denaturation, solubilization, aggregation or gelation. This modification depends on the protein system (specie, type and formulation) and HHP condition (pressure intensity, pressurizing gradient, duration time, temperature, pressure/temperature and the sequence of application). However, there remains a lack of a systematic summary of structural changes and structure-function relationship of MP in response to various HHP conditions. Hence, this review first explored the profound knowledge on the structural and functional changes of MP induced by HHP based on previous works and recent progress. Second, to meet the growing demand for economical, nutritional and healthy meat products, recent applications of HHP on the manufacture of low salt, low phosphate and/or low fat gel-type meat products, as well as value-added and texture-modified meat products were highlighted. Finally, future considerations were presented to facilitate progress in this area and to enable HHP as an efficient strategy in tailoring the manufacture of functionally improved, value-added and healthy muscle gelled foods. [ABSTRACT FROM AUTHOR]

Consumption of dietary protein at recommended levels is considered a potential strategy to promote satiety and weight management, but how protein from different dietary sources effect the obesity development, lipid metabolism, and gut microbiota is not known. This study focused on the effects of beef, casein, and soy protein diet on lipid metabolism, triglycerides accumulation, and microbial diversity in colon of C57BL/6J mice, which were given either low-fat diets (LFD, 12% Kcal) or high-fat diets (HFD, 60% Kcal) for 12 weeks. Body and liver weight increased significantly in mice fed a beef protein HFD (HFB), whereas reduced cumulative energy intake was seen in a soy protein HFD (HFS) group. HFB-fed mice showed signs of impaired glucose metabolism and insulin resistance along with a significant elevation in the concentration of triglycerides, LDL-cholesterol, total cholesterol, IL1β, TNF-α, IL-6, and leptin in serum. HFB also enhanced lipid accumulation in liver with increased activity of genes important for lipogenesis and hepatic cholesterol metabolism. A 16S rRNA gene sequencing indicated that HFD, regardless of proteins, significantly enhanced the ratio of Firmicutes to Bacteroidetes in colonic microbiota. However, HFB not only reduced the abundance of Akkermansia , compared with LFD independent of proteins, but also decreased the abundance of butyrate-producing bacteria such as Anaerotruncus , Butyricicoccus , and Lactobacillus (P < 0.05) compared with HFS and HFC. In conclusion, consumption of HFB does not only affect the gut microbiota composition but also increases the problems related to metabolic syndromes like dyslipidemia, hypercholesterolemia, and triglycerides accumulation in liver, which lead to systemic inflammation and its associated comorbidities, for example, impaired glucose metabolism and insulin resistance. [ABSTRACT FROM AUTHOR]

Summary: The potential of nonenzymatic glycation of myofibrillar proteins (MPs) to improve the gelation functionalities of pale, soft and exudative (PSE‐like) chicken breast meat was investigated. MP suspensions (4 mg mL−1) obtained from both normal and PSE‐like chicken breast meat were mixed with glucosamine at a ratio of 1:6 (protein : glucosamine) in phosphate‐buffered saline (0.6  m KCl, 20 m m K2HPO4/KH2PO4, 0.02% NaN3 and pH 7.5) and incubated at 37 °C for 12 h. Untreated normal and PSE‐like MP suspensions maintained at 4 °C were used as positive and negative controls, respectively. The glycation treatment increased the surface hydrophobicity but decreased the reactive sulfhydryl contents compared to those of the control (P < 0.05), indicating that the tertiary conformation of the protein changed. Correspondingly, these glycated samples also exhibited significant improvements in gel strength and the water‐holding capacity (P < 0.05). Conclusively, nonenzymatic glycation is a potential technique to improve the properties and offer a means for effective use of PSE‐like meat. [ABSTRACT FROM AUTHOR]

Abstract: This work investigated the effects of refrigerated storage (RS: 4 ± 1°C) and superchilled storage (SS: −2.5 ± 1°C) on non‐volatile and volatile compounds in chicken soup made from Chinese yellow‐feather broilers. The results from total viable count (TVC) and coliform analysis showed that soups were safe for human consumption after a storage period of 42 days. SS resulted in a significantly (p < .05) higher content of free amino acids (umami and sweet taste) and 5′‐nucleotides (inosine 5′‐monophosphate and adenosine 5′‐monophosphate) from 21 to 42 days compared to RS. Hexanal, (E)‐2‐decenal, (E,E)‐2,4‐decadienal and 2‐pentyl furan were described as the primary odorants. SS showed significantly lower values (p < .05) for ketones and hydrocarbons, higher values for aldehydes and alcohols from 14 to 42 days, when compared to RS. The results suggest that SS improved the flavor retention of chicken soup after 21 days of storage and is a potential alternative treatment compared to RS. [ABSTRACT FROM AUTHOR]

Summary: This study aimed to investigate the effect of flaxseed gum (FG) on the retrogradation of maize starch (MS) gels under different storage temperatures. In this work, MS‐FG gels with 0–0.4% FG were stored under different temperatures (–20, 4 and 20 °C). Under all storage temperatures, the addition of FG inhibited the retrogradation process of MS, suppressed the recrystallisation of starch molecules, reduced the water loss of starch gels and improved the texture of the gels. Among the three storage temperatures, −20 °C could almost stop the starch retrogradation but leading it results in the hardest gel texture. The retrogradation of MS‐FG gels stored under 4 °C was most serious with the fastest rate of recrystallisation. When stored at 20 °C, the gels had a retrogradation degree that was lower than when they were stored at 4 °C and also had the softest texture. [ABSTRACT FROM AUTHOR]