Yogurt is highly sought after by consumers because of its unique flavor, rich nutritional value and health care function. However, during its sale and storage, some undesirable phenomena such as unstable gel structure and whey precipitation are prone to occur, which has affected the further development of yogurt industry to some extent. Polysaccharides and proteins act as typical thickeners and stabilizers in food, enhancing the structural stability of yogurt gel through different mechanisms. Anionic polysaccharides interact with casein electrostatically to form complexes, while neutral polysaccharides rely on their hydration capacity and act as fillers to stabilise the three-dimensional structure of yogurt. Milk proteins and vegetable proteins play a stabilising role mainly through hydrophobic interactions and disulphide bonds. Gelatin, on the other hand, relies on its good hydration capacity and gelation properties. Polysaccharide and protein complexes mainly rely on non-covalent interactions to stabilise the yogurt gel structure. This paper reviewed the mechanisms of yogurt gel formation and the factors that affect yogurt texture. It also summarized the research progress on enhancing the structural stability of yogurt gel using polysaccharides and proteins as well as their complexes as additives, with a view to providing theoretical bases for improvement of the textural properties of yogurt.

This study investigated the effects of a xylitol-casein non-covalent complex (XC) on parameters related to type 2 diabetes mellitus (T2DM), in addition to related changes in gut microbiome composition and functions. High-fat-diet (HFD) + streptozotocin (STZ)-induced T2DM mice were treated with xylitol (XY), casein (CN), and XC, after which fecal samples were collected for gut microbiota composition and diversity analyses based on 16S rRNA high-throughput sequencing and multivariate statistics. XC decreased body weight and improved glucose tolerance, insulin sensitivity, pancreas impairment, blood lipid levels, and liver function in T2DM mice compared to XY- and CN-treated mice. Furthermore, XC modulated the α-diversity, β-diversity and gut microbiota composition. Based on Spearman’s correlation analysis, the relative abundances of Alistipes, Bacteroides, and Faecalibaculum were positively correlated and those of Akkermansia, Lactobacillus, Bifidobacterium, and Turicibacter were negatively correlated with the phenotypes related to the improvement of T2DM. In conclusion, we found that XC alleviated insulin resistance by restoring the gut microbiota of T2DM mice. Our results provide strong evidence for the beneficial effects of XC on T2DM and motivation for further investigation in animal models and, eventually, human trials.

Donkey milk has a variety of physiological functions, including antibacterial and anti-inflammatory. Donkey whey proteins (DWPs), as the main functional component in donkey milk, its inhibitory effect on colitis is still unclear. In this study, the inhibitory effect and potential mechanism of DWPs on dextran sulfate sodium (DSS)-induced colitis were investigated. Firstly, the DWPs and bovine milk whey proteins (BWPs) were characterized using proteomics. Then, we administered DWPs and BWPs to mice with colitis via oral gavage. The results of immunohistochemistry and flow cytometry indicated that DWPs increased T regulatory cell accumulation and increased the abundance of the cluster of differentiation 205⁺ (CD205⁺) macrophages compared to those with BWPs and in model groups. In addition, DWPs exhibited a more remarkable ability to inhibit pro-inflammatory proteins (S100A8, TRAF6, and NF-κB) expression and inflammatory secretion than BWPs. In addition, DWPs significantly decreased NF-κB and CD86 levels more than BWPs or the negative control in both LPS-stimulated human peripheral blood mononuclear cells or cell lines. These findings indicate that DWPs comprise a promising anti-colitis functional food, and this work has established a foundation for future research on these compounds.

This study aimed to analyze and compare the differentially expressed whey proteins (DEWPs) of donkey and bovine colostrum using high-performance liquid chromatography with tandem mass spectrometry-based proteomics. A total of 620 and 696 whey proteins were characterized in the donkey and bovine colostrum, respectively, including 383 common whey proteins. Among these common proteins, 80 were identified as DEWPs, including 21 upregulated and 59 downregulated DEWPs in donkey colostrum compared to bovine colostrum. Gene Ontology analysis revealed that these DEWPs were mainly related to cellular components, such as extracellular exosome, plasma membrane, and mitochondrion; biological processes, such as oxidation-reduction process, cell-cell adhesion, and small guanosine triphosphate (GTP) ase-mediated signal transduction; and molecular functions, such as GTP binding, GTPase activity, and soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor activity. Metabolic pathway analysis suggested that the majority of the DEWPs were associated with soluble NSF factor attachment protein receptor interactions in vesicular transport, fatty acid biosynthesis, and estrogen signaling pathways. Our results provide a vital insight into the differences between donkey and bovine colostrum, along with important information on the significant components as nutritional and functional factors to be included in infant formula based on multiple milk sources.