內(nèi)容: Six phenolic acids (PAs) with related structures, i.e., gallic acid (GA), syringic acid (SA), coumaric acid (CMA), caffeic acid (CFA), ferulic acid (FA), and chlorogenic acid (CA), were compared for their effects on the gelling properties of myofibrillar protein (MP) under oxidative conditions. Of the six PAs, only the smallest GA caused significant reductions of free amine and sulfhydryl content (by 26% and 7%, respectively,?P?< 0.05) and SA decreased protein carbonyl formation, while CA, the largest PA with an esterified quinic group, prevented oxidative loss of amines. All PAs quenched MP fluorescence with CA showing the highest efficacy (38% suppression). During thermal gelation, the GA-modified MP displayed the strongest myosin cross-linking. The elasticity (G′) and breaking strength of MP gels were markedly enhanced by the addition of PAs, and the final?G′ value ranked in the order GA > CA > FA > CMA > SA > CFA, indicating complex roles of phenolic side groups.

內(nèi)容: The concept of healthiness and sustainability have triggered consumers into choosing healthier food, especially “clean-label” products. Porcine skin is a natural “clean-label” raw material, and direct usage of whole pork skin as an additive has been proven as an efficient way to deal with the by-product issues and also satisfies the “clean label” demands of consumers. However, efficient approaches to convert bulk skin into handy powders in a green-fabrication manner while maintaining its unique properties have yet to be fully investigated. Herein, we provided two green approaches, drying-grinding, and wetting-grinding, to prepare pork skin functional protein powder (FPP), and their chemical composition, structure, properties, stability, and functionality are systematically investigated. Specifically, FPP prepared by two methods exhibit similar chemical composition and great thermal stability. Notably, FPP prepared by drying-grinding method is superior in flow ability, water dispersion, and texture properties of FPP gels as compared to wetting-grinding method. Structural analyses revealed that the superior properties of FPP prepared by drying-grinding method depend on the intrinsic natural triple helix structure of collagen. Overall, this work revealed the underlying key factors for the preparation of FPP with excellent properties, and highlighted that the FPP prepared by drying-grinding method is more suitable for practical application as “clean-label” additives in the food industry.

內(nèi)容: This paper investigated the changes in the texture, flavor, nutrition, and digestive characteristics of soft-boiled and marinated eggs (SME) during pressurized heat treatment (PHT) at 121 ℃ and 125 kPa for 15, 30, and 45 min. Eggs were pre-cooked in boiling water for 5 min, cooled and peeled in cool water, and then immersed in the brine at 65 ℃ for 2 h to prepare marinated eggs. The results showed that the hardness of SME (121 ℃, 0 min) was the lowest, with the egg white and yolk hardness were 1 368.05 and 530.43 g, respectively. After 15 min of PHT, the hardness of egg white and yolk increased significantly to 2 077.54 and 1 492.75 g (P?< 0.05). The relaxation time of non-fluidizable water and free water of egg yolk decreased after PHT. The electronic nose test clearly distinguished the flavor difference before and after PHT, and moderate lipid oxidation was helpful to form new flavors. The protein digestibility of the SME yolk was significantly higher than the PHT groups. Vitamin A content of the SME (0.24 mg/100 g) was 1.26 times higher than the 30 min PHT group. After 30 min heat treatment, the vitamin E content of egg yolk decreased by 7.88%, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) decreased significantly from 2.02 and 1.52 g/100 g to 1.73 and 0.92 g/100 g, respectively. Low temperature group (SME) maintained higher levels of fat-soluble vitamins and lecithin in the egg yolk than PHT groups.

內(nèi)容: This study investigated the effects of five lipases on enzyme-modified cheese (EMC) flavor development. Results showed that lipase 30SD contained high hydrolytic activity for short, medium, and long-chain fatty acids within 24 h incubation time, and the highest content of them among different times could reach 47.24, 475.90, 1 563.92 mg/100 g fat, respectively. Lipase DF15 and MER showed moderate capacity to hydrolyze volatile fatty acids, while lipase F3G had a stronger ability to produce long-chain fatty acids. Twenty-seven new volatiles were formed during lipolysis, most of them were acids and esters. Principal component analysis results showed that EMC produced by lipase 30SD for 18 h was similar to the commercial product with a pungent, rancid, and cheddar flavor. EMCs produced by lipase DF15 were significantly distinguished from other products by their high content of ethyl heptanoate, ethyl nonanoate, and ethyl tridecanoate. The findings might be useful for the researchers who focus on lipolysis or EMC products.

內(nèi)容: Cattleyak, the interspecies hybrid from cattle (males) and yak (females), displays a faster growth rate and higher feeding efficiency than yak with usually one-year shorter raising cycle. This study aimed to assess the carcass characteristics and meat quality attributes of cattleyak by compared to yak at a similar bodyweight. Results showed that cattleyak exhibited an elevated dressing percentage (58.33%) and a significantly higher content of healthy fatty acids, including eicosapentaenoic acid (5.64%) and docosahexaenoic acid (0.46%) (P?< 0.05). Compared to yak meat, the tenderness of cattleyak meat was significantly enhanced (P?< 0.05), with the lower Warner-Bratzler shear force (59.53 N) and hardness value (580.92 g), as well as the significant reduction of more than 20% of muscle fiber diameter (P?< 0.05). Additionally, myofibrillar proteins in cattleyak, including desmin, tropomyosin, and troponin-T, degraded faster than those in yak (P?< 0.05), indicating their role in tenderization improvement in cattleyak. These findings suggest that, in comparison to yaks of the similar bodyweight, cattleyaks with less than one year of the raising cycle have improved meat quality and economic efficiency.

內(nèi)容: The synergetic effect of nisin and high-pressure carbon dioxide (HPCD) on structural changes and leakage of nucleic acid, soluble proteins, Mg2+, Ca2+, K+, and dipicolinic acid from?Bacillus subtilis?spores was studied. Both HPCD and nisin auxiliary were used to inactivate the?B. subtilis?spores. The death rate of spores treated by HPCD combined with the nisin were significantly higher than HPCD alone (P?< 0.05). The main cause of spore’s death is the leakage of components caused by the change of spore permeability and structural damage. The HPCD treatment damaged the spore ultrastructure, resulting in the leakage of nucleic acid, Mg2+, Ca2+, K+, and dipicolinic acid from spores, while nisin auxiliary to HPCD treatment damaged spore membrane, which led to spore death and play a synergetic effect. This study evaluated synergetic effects of HPCD combined with the bacteriocin nisin. The investigation provided evidence for potentially combined application of HPCD and nisin to help ensure food safe in the industry.

內(nèi)容: The deterioration of wooden breast myofibrillar protein (WBMP) increases with the increase in wooden breast grades. In order to quickly and conveniently classify wooden breast to prevent waste of raw materials and unsuitable processing. Different grades of wooden breasts that exhibited mild, moderate, and severe degrees were collected, and correlation analysis was employed for the quality and WBMP functional characteristic indicators. The indicators were further classified into two components according to the principal component analysis method. Based on the correlation and variation coefficients, two main indicators were selected to represent the quality level of wooden breasts (redness (a*) and pH value (P)). The weights of the two indicators were 0.353 and 0.219 for?a* and?P, respectively, using the weighted coefficient method. Therefore, a formula for calculating the comprehensive evaluation score (y) of different grades of wooden breast meat was obtained:?y?= 0.353a* + 0.219P. Based on regression analysis, the fitting equation?y?= 2.407 1x?+ 0.0343 (R2?= 0.9883) was obtained, for the comprehensive quality score (y) and sensory evaluation score (x) through regression analysis, with a fitting coefficient ? 0.8. This equation can accurately predict sensory evaluation scores, effectively reflect the quality differences of different grades of wooden breasts, and accurately and rapidly grade wooden breasts.

內(nèi)容: A two-step rapid fermentation shrimp paste process based on strain enhancement was developed by inoculating functional strains into shrimp paste in two steps. This improved the drawbacks of traditional fermented shrimp paste products, such as their lengthy fermentation times, high salt contents, and unstable fermentation quality. Single factorial and response surface analyses was employed to optimize the two-step fermentation process, and the physicochemical indices, sensory and volatile components of the rapid fermentation products were analyzed and compared with the uninoculated fermented shrimp paste. The results showed that the optimal process parameters for the one-step fermentation with?Cladosporium?Z3 were 12 d, 21 ℃ and 3% (V/V) inoculum, and the optimal parameters for the two-step fermentation with?Enterococcus faecalis?X1 were 4 d, 25 ℃ and 4% (V/V) inoculum. Compared with the uninoculated fermented shrimp paste, the two-step fermented shrimp paste samples with starters had higher amino acid nitrogen (AAN) content, more complete protein hydrolysis and lower total volatile base nitrogen (TVB-N) content, while the two-step fermentation method with intensified starters was able to promote the formation of good flavor and the good quality of shrimp paste.

內(nèi)容: This study focused on the effect of tea polyphenols on the quality changes of low-salt grass carp cured products during refrigeration. The addition of tea polyphenols could be found to improve the color and texture of the cured grass carp products during the refrigeration process. The bacterial colonies (TVC) and total volatile basic nitrogen (TVB-N) content showed that the conditioned grass carp fillets had a high level of food safety. The thiobarbituric acid reactive substance (TBARs) value of grass carp continued to rise with increasing refrigeration time, indicating that fat oxidation occurred in the grass carp cured products. The addition of tea polyphenols was found to inhibit protein oxidation and protect the protein structure of the low-salt conditioned grass carp fillets during refrigeration, as indicated by the indicators related to protein oxidation. This finding provides a new theoretical idea for grass carp processing and storage.