In order to improve the flavor and quality of goat milk yogurt and enhance its functional value, Lactobacillus plantarum JS5 and JS19, isolated from Jiangshui, a traditional Chinese fermented vegetable food, were used for goat milk fermentation. The physicochemical properties, textural characteristics, and functional properties of goat milk yogurt were evaluated. The results showed that mixed-culture fermentations with each isolate and a commercial starter culture improved the water-holding capacity and apparent viscosity of goat milk yogurt, reduced its hardness and gumminess and promoted the release of acetaldehyde and diacetyl. The rate of cholesterol degradation (up to 36.62%) in goat milk yogurt containing Lactobacillus plantarum JS5 was significantly higher than that in the control group (P < 0.05). Goat milk yogurt containing Lactobacillus plantarum JS19 showed stronger antioxidant capacity in vitro, which could scavenge 70.58% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and had a ferric ion reducing antioxidant power (FRAP) value of 32.03 μmol ferrous sulfate equivalent/L on the first day of storage. Therefore, both strains are suitable for goat milk fermentation.

In order to obtain more data on proteins in goat milk, cow milk and human milk, their basic components were determined, and bioinformatic analysis of their proteins was performed by proteomics. The results showed that the protein contents of goat milk and cow milk were higher than that of human milk, while the contents of fat and lactose were higher in human milk. A total of 3 370 proteins were identified in the three kinds of milk, and gene ontology (GO) analysis of these proteins indicated that they were mainly involved in biological processes such as cell process and metabolism process, and distributed in the cell, organelles and extracellular region. Their molecular functions included binding and catalytic activity. The KEGG pathway varied in the three kinds of milk and was enriched in protein processing in the endoplasmic reticulum. In the protein-protein interactions network, the 307 shared proteins participated in several pathways such as carbon metabolism, glycolysis/gluconeogenesis, and amino acid biosynthesis.