Daobang Tang

Egg-based yoghurt (EBY) is a novel yoghurt fermented by lactic acid bacteria with high nutritional and health values, serving as a potential alternative to milk-based yoghurt. However, the hardness, adhesiveness, and water-holding capacity of egg-based yoghurt need to be further improved. In this study, the improvement in EBY quality by gellan gum and its underlying mechanism were investigated. The results showed that gellan gum significantly improved the quality of EBY (p < 0.05). Among the five concentration gradients tested, the EBY supplemented with 0.045% gellan gum exhibited the best quality with the highest sensory score of 83.57. With the increasing amount of gellan gum, hydrogen bonding interactions in the yoghurt significantly increased, while ionic bonding remained unchanged, but hydrophobic interactions and disulphide bonding gradually decreased. Low-field NMR assay results demonstrated that gellan gum significantly raised the amount of strongly bonded water while decreasing the amount of immobile water in the yoghurt. Confocal laser scanning microscopy revealed that EBY with 0.045% gellan gum had a better texture, whereas too much or too little gellan gum led to a coarser structure. In summary, gellan gum altered the water phase state and enhanced the water holding capacity through increased hydrogen bonding interactions, which consequently improved the yoghurt’s texture and sensory qualities. This study provides a reference for the development and application of EBY.

Compound fermented seasonings were increasingly favored by consumers. This study using Aspergillus oryzae and soybeans as raw materials to make koji. Lactobacillus plantarum and Pediococcus pentosaceus were used as starters for common fermentation with mature koji and beef to obtain a fermented beef-soybean paste. The physicochemical parameters, volatile flavor compounds, and microbial community of beef-soybean paste during fermentation were determined, and the relationship between flavor changes and microbial community changes was analyzed. Compared to the soybean paste, the addition of beef for fermentation can significantly enhanced the content of protein, amino acid nitrogen, and free amino acids in the compound fermented soybean paste, improved the nutritional and health value of the product. The addition of beef also caused a decrease in pH and total acid content in the compound soybean paste. The flavor changed during the fermentation process of beef-soybean paste were related to the changed in its microbial community.

Chlorogenic acid (CA), gallic acid (GA), and resveratrol (RES) were added to a gelatin (GEL)-chitosan (CHI)-glycerol (GLY) edible coating, and their effects on the coating of fresh beef preservation were investigated. The results revealed that CA had the most significant improvement effect on fresh beef preservation. The combination of GEL-CHI-GLY-CA preserved the color of the beef better and delayed the increase of the total volatile base nitrogen, even though its total phenolic content decreased at a faster rate during beef preservation. GA also improved the preservation effect as on the 12th day of storage, the beef samples treated with GEL-CHI-GLY-GA had the lowest thiobarbituric acid reactive substances (0.76 mg Malondialdehyde (MDA)/kg) and total viable count (6.0 log cfu/g). On the whole, though RES showed an improvement on beef preservation, the improvement was not as good as the other two polyphenols. After 12 days of storage, the beef samples treated with GEL-CHI-GLY-RES had a higher pH value (6.25) than the other two polyphenol treatmed groups. Overall, the three polyphenol-added combinations increased the shelf life of beef by approximately 3–6 days compared to the control group (treated GEL-CHI-GLY with distilled water).

Chalcone-1-deoxynojirimycin heterozygote (DC-5), a novel compound which was designed and synthesized in our laboratory for diabetes treatment, showed an extremely strong in vitro inhibitory activity on α-glucosidase in our previous studies. In the current research, its potential in vivo anti-diabetic effects were further investigated by integration detection and the analysis of blood glucose concentration, blood biochemical parameters, tissue section and gut microbiota of the diabetic rats. The results indicated that oral administration of DC-5 significantly reduced the fasting blood glucose and postprandial blood glucose, both in diabetic and normal rats; meanwhile, it alleviated the adverse symptoms of elevated blood lipid level and lipid metabolism disorder in diabetic rats. Furthermore, DC-5 effectively decreased the organ coefficient and alleviated the pathological changes of the liver, kidney and small intestine of the diabetic rats at the same time. Moreover, the results of 16S rDNA gene sequencing analysis suggested that DC-5 significantly increased the ratio of Firmicutes to Bacteroidetes and improved the disorder of gut microbiota in diabetic rats. In conclusion, DC-5 displayed a good therapeutic effect on the diabetic rats, and therefore had a good application prospect in hypoglycemic drugs and foods.

Slowly digestible gorgon nut starch (GN-SDS) was prepared by heating–cooling treatment (HCT), meanwhile its morphological and structural features were characterized in detail by SEM, DSC, XRD and IR detection. The optimized parameters of GN-SDS processing were as following: starch milk (20%) was heated at 100 °C for 20 min, and then cooled under 4 °C for 24 h. Under the optimized parameters, the SDS content increased from 20.49 to 61.74%. GN-SDS showed typical SDS characteristics in in vivo digestion with a low postprandial blood glucose. SEM images suggested that GN-S particles changed from uniform regular polyhedron with smooth surface to irregular gravel-like particles with coarse surface and obvious layered structure inside after HCT. The results of SEM, DSC, XRD and IR determination indicated that HCT changed the granule morphology, interior structure, gelatinization temperature and crystal type (A to B-type) of GN-S, and therefore made it hard to be digested accordingly.

BACKGROUND Prepared chicken breast deterioration is a complex biochemical process, of which protein change is one of the main reasons. The present research focuses on the analysis of proteins related to the deterioration of quality of prepared chicken breast through differential proteomics analysis. RESULTS The physicochemical indexes of prepared chicken breast showed that the quality gradually decreased at the second week of refrigerated storage, while the deterioration of chicken breast meat was obvious at the third week. Three key time points of quality change were determined to be at 0^th, 2^th and 5^th week, respectively. In addition, 39 differential proteins were successfully identified using two‐dimensional gel electrophoresis (2‐DE) and matrix‐assisted laser desorption/ionization time of flight mass spectrometry (MALDI‐TOF‐MS). Most of the identified proteins showed significant differences in expressions at the three key points of storage, of which actin, myosin, alpha‐1, 4 glucan phosphorylase, phosphoglucomutase 1, heat shock protein beta‐1, tubulin beta‐7 chain and skeletal muscle type tropomodulin (Fragment), were closely related to the quality deterioration of prepared chicken breast, and expected to be indicator proteins to evaluate the quality of chicken breast. CONCLUSION The current study indicated that the physicochemical quality of prepared breast notably changed during refrigerated storage. Three key time points of quality change in the storage process of prepared chicken breast were determined. Furthermore, differential proteomics identified the key proteins related to freshness, which provides a theoretical basis for exploring the mechanism of chicken breast deterioration.