This study was conducted in order to investigate the effect of Lactobacillus helveticus LH43, which has the ability to produce high-molecular-mass extracellular polysaccharides, as an auxiliary starter on the gel properties and protein conformation as determined using a texture analyzer, a rheometer, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), fluorescence spectrophotometry and circular dichroism (CD) spectroscopy. The results showed that the application of L. helveticus LH43 as an auxiliary starter significantly enhanced the textural properties, water-holding capacity (WHC) and rheological characteristics of yoghurt and improved its microstructure and flavor characteristics. Additionally, the strain reduced the surface hydrophobicity, free sulfhydryl content and relative content of random coil of yoghurt proteins, and increased the relative content of α-helical structures, confirming α-helix and random coil to be intrinsic factors leading to differences in the gel properties of fermented milk. In conclusion, L. helveticus LH43 can be used to improve the gel properties of dairy products, and this study provides a new reference for improving the fermentation process of yoghurt.

Breast milk is the safest and most perfect natural food for infant growth and development. As one of the most important components in breast milk, the milk fat globule membrane (MFGM) is a 3-layer membrane structure surrounding milk fat globules (MFG). This unique structure not only maintains the stability of milk but also plays an important role in the digestive and metabolic processes of infants. In this article, we introduce the reader to the composition and structural specificity of MFGM, review the sequential digestion of MFGM depending on several enzymes in the mouth, stomach and intestine of healthy infants, and elaborate on the interaction mechanism between MFGM and various enzymes, in order to provide a reference for relevant studies.

2’-Fucosyllactose (2’-FL) shows the potential to support intestinal health as a natural prebiotic that bridges the gap between infant formula feeding and breastfeeding. However, the effect and mechanism of 2’-FL in improving intestinal permeability are not clear. In this study, we constructed human microbiota-associated (HMA) mouse models by colonizing healthy infant feces in mice with antibiotic-depleted intestinal microbiota. The protective effect of 2’-FL on the intestinal permeability was explored using the HMA mouse models, and the combination of metagenomics was used to analyze the possible mechanisms by which the microorganisms reduced the intestinal permeability. The results showed that 2’-FL decreased the concentration of markers of intestinal permeability (enterotoxin and diamine oxidase (DAO)) and increased the expression levels of tight junctions (occludin and claudin). Metagenomics revealed the enrichment of Bifidobacterium and increased the expression of glycoside hydrolases (GHs), including GH31, GH28, and GH5. In conclusion, 2’-FL strengthened intestinal permeability function by improving microbiota composition to control the translocation of harmful substance.

Infant formula (IF) based on cow milk and goat milk is a substitute food for infants who are underfed with human milk. In our previous study, we reported the composition and physicochemical stability of IF based on milk from cows and goats and a combination of both milks. Here, we investigated the effects of these 3 IFs on intestinal immunity and short-chain fatty acid production (SCFAs) using human microbiota-associated (HMA) mice and selected human milk as a positive control. The results showed that goat milk-based IF is associated with a functional immune advantage, due to the rise in the levels of immune-related cytokines interleukin (IL)-2 and IL-10, decreased levels of intestinal permeability markers D-lactic acid and endotoxin, and increased mRNA levels of intestinal tight junction proteins occludin and claudin. In addition, the intestine of mice fed with goat milk -based IF contained 12.06 μmol/g acetate, 2.42 μmol/g propionate, and 1.72 μmol/g butyrate, which reached 69%, 79 %, and 60% of the levels in human milk, respectively. Our results indicate that goat milk-based IF improves intestinal immune function and promotes the production of intestinal SCFAs.