Analysis of Flavor Substances and Microbial Diversity in Nautral Starter of Koumiss in Xilin Gol Pastoral Area

In this experiment, the natural starter of koumiss in Xilin Gol pastoral area was used as the research object to explore its flavor substances and microbial diversity. Liquid - liquid extraction - gas chromatography-mass spectrometry (LLE-GC-MS) was used to determine the flavor compounds and Illumina MiSeq high-throughput sequencing technology was used to sequence and analyze the V3-V4 variable region of bacterial 16S rRNA gene and ITS region of fungal gene, and their related metabolic pathways were analyzed and predicted. The results showed that a total of 43 flavor substances were detected in the natural starter, the main flavor substances were L-lactic acid, palmitic acid, lauric acid, ethyl caprylate, ethyl lactate, ethyl laurate, 2, 3-butanediol, dodecanethiol, isoamyl alcohol, etc. A total of 180069 bacterial and 187397 fungal sequences were obtained by high-throughput sequencing. The bacterial community mainly included Lactobacillus, Acetobacter, Lactococcus and Streptococcus, among which Lactobacillus was the dominant bacterium and the relative abundance was 72.26%. The fungal community mainly consisted of Dekkera and Kluyveromyces, among which Dekkera was the dominant fungal genus with a relative abundance of 94.09%. According to the prediction of gene function, carbohydrate metabolism and amino acid metabolism of starter were prominent, and there were a lot of enzyme genes in the metabolic pathway, which would lay a genetic foundation for the formation of flavor substances in the fermentation process of koumiss.