Haibo Shi

The changes and gastric digestive properties of gel were investigated for oxidized myofibrillar protein (MP) (0 – 1 mmol/L H₂O₂) treated by 30% substitution of NaCl with KCl, MgCl₂, and KCl/MgCl₂. Mild oxidation level (0.3 mmol/L H₂O₂) facilitated the protein unfolding, and MgCl₂ obviously intervened the protein self-assembly by forming the salt bridge and more disulfide bonds. At the same oxidation concentration, the sodium-reduced MP substituted with KCl formed dense network structure with better gel strength (increased by 6% – 18%) and water retention in comparision to the gel without sodium reduction. The KCl-substituted gel chewing work was also relatively higher among the low-sodium samples at the first chewing cycle. Reversely, the relatively soft structure and lower gel viscosity in simulated oral chewing were found in MgCl₂-substituted gel. These changes decreased the contact limit between pepsin and protein for better gastric disintegration or pepsin diffusivity, and increased the proportion of small molecular weight peptides (25.83%, < 5 kDa). Therefore, partial substitution of NaCl with other salt replacers could influence the physicochemical properties of low-sodium MP suspension or gel under different oxidation degree and the subsequent gastric digestion characteristics.

The protein structure, gel changes, and chewing properties of low‐sodium myofibrillar protein (MP) prepared by compound chloride salts (KCl/MgCl ₂ , KCl/CaCl ₂ , and KCl/MgCl ₂ /CaCl ₂ ) and different substitution degrees (10%, 25%, and 40%) at same ionic strength (0.6 M) were investigated. The results revealed that the low‐sodium MP gels containing CaCl ₂ manifested more liquid loss and less moisture content accompanied by obvious morphological shrinkage, while KCl/MgCl ₂ contributed to the gel juiciness. At high substitution degree of 40%, KCl/CaCl ₂ substitution rendered the gel with dense structure and highest strength, but worse water retention capacity. Using other compound chloride salts influenced the chewing efficiency, and CaCl ₂ substitution made the gel relatively hard to chew. The inhomogeneous structure accompanied by cluster blocks in KCl/CaCl ₂ ‐substituted MP gel accelerated the overall fracture rate. During heating process, more proteins in CaCl ₂ ‐substituted MP did not participate in gel formation, intervening the final gel properties. The chloride salt mixtures containing MgCl ₂ , rather than CaCl ₂ , avoided or alleviated the liquid loss and shrinkage of low‐sodium MP gel within the substitution degree of 10%–40%, and substitution degree not exceeding 25% was more reasonable for the controlled qualities.

The anti-inflammatory effect of ellagic acid (EA) and its possible underlying mechanism in dextran sulfate sodium (DSS)-induced mouse chronic colonic inflammation were studied. It was observed that EA administration significantly alleviated the colonic inflammation phenotypes, including decreasing the disease activity index (DAI), enhancing the body weight loss, and improving the shortened length of the colon and pathological damage of colon tissue. Additionally, EA reshaped the constitution of the gut microbiota by elevating the ratio of Bacteroidetes along with Bacteroides and Muribaculaceae, while decreasing the proportion of Firmicutes. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2 (PICRUSt2) revealed that the metabolic function of the gut microbiota was also changed. Furthermore, mouse colon transcriptome analysis showed that the tight junction and peroxisome proliferator-activated receptor (PPAR) signaling pathways were activated and the expressions of related genes were upregulated after EA intervention. These results showed that EA could remodel the gut bacterial composition, change the intestinal epithelial cell gene expressions in mice, and consequently improve the colonic inflammatory symptoms.

The study investigated the effects of compound fibers composed of psyllium husk powder (PHP, 0.3%) and methylcellulose (MC, 0, 0.3, 0.6, 0.9, and 1.2%) on the storage stability, rheology, and microstructure of sodium caseinate emulsions. Results showed that the emulsion stability was enhanced with the increased concentrations of MC, especially at the concentration of 1.2%. The oil droplet size in the emulsions was decreased as the concentrations of compound fibers increased, which was further confirmed by the optical microscope analysis. The rheological measurements and cryo-scanning electron microscopy results indicated that compound fibers improved the viscosity of the emulsions, and formed a strong three-dimensional network structure. The results of confocal laser scanning microscope and surface protein concentration measurements showed that compound fibers were evenly distributed into the oil droplet surface. The above results demonstrate that compound fibers are an effective thickener and emulsifier in enhancing the stability properties of oil-in-water (O/W) emulsions stabilized by sodium caseinate.

Fatty acid profile, protein and fatty acid oxidation and flavor profile of pan-fried chicken patties formulated with various levels of Perilla frutescens seed meal (PSM) as a fat substitute was investigated in this study. The formation of heterocyclic amines (HCAs) in the chicken patties was also evaluated. The results showed that pan-fried patties formulated with 20% PSM (PSM4) had the highest ranges of oleic acid and ΣMUFA content and ΣPUFA/ΣSFA ratio. Low to medium levels of PSM (PSM1, 2, and 3 corresponding to 5, 10, and 15% of PSM, respectively) reduced the content of lipid peroxidation products, while high level (PSM4) increased it. All levels of PSM were also found to be effective against elevation in carbonyl content relative to the control. Moreover, the PSM effectively inhibited HCA formation in the chicken patties. The total contents of HCAs in PSM1, PSM2, PSM3, and PSM4 samples were significantly (P < 0.05) lower than that of the control sample, corresponding to 31.9, 46.1, 57.2, and 44.8% inhibition, respectively. PSM4, however, had no or very little effect on the formation of PhIP, 4,8-DiMeIQx and AαC, despite a strong inhibitory effect on MeIQx formation. These findings not only support the promising potential of PSM for application as a fat substitute to improve the fatty acid profile and reduce the content of harmful by-products in heat-processed chicken, but also highlight that appropriate addition level is a critical factor in optimizing the functional capacity of this natural agent.