Microbiological profiles, physiochemical properties and volatile compounds of goat milk kefir fermented by reconstituted kefir grains

Kefir is a health-promoting fermented dairy products, consisting in a variety of bacterial and fungal species. The physical and chemical properties and the correlation between the microbiota and volatile compounds of goat milk kefir fermented by reconstituted kefir grains were investigated. Cluster analysis showed that a strong symbiotic homeostasis system existed in goat milk kefir, indicating that the composition of microorganism in reconstituted kefir grains was still restricted by the original one. Compared with other kefir samples, goat milk kefir 80DE20CN (ratios of kefir grains CN/DE = 80/20) showed significant improvement in physiochemical properties and "Fruity" flavor. Positive correlations among Lactobacillus helveticus and ethyl acetate, amyl acetate and ethanol, Kazachstania unispora and octyl formate, 1-heptanol and hexanoic acid were obtained by Partial least squares regression analysis (PLSR) model. The results showed that changes in microbial succession patterns may be useful to optimize the physiochemistry and flavor of goat milk kefir or related products.