Correlation Analysis between Bacterial Community Succession and Changes of Flavor Substances during Whey Wine Fermentation

In this study, gas chromatography-mass spectrometry (GC-MS) was used to analyze the changes of important aroma components in whey wine, and high-throughput sequencing technology was used to analyze the bacterial community changes in whey wine. Moreover, correlation analysis was conducted between aroma components and bacterial community. The results showed that the number of flavor substances generally increased during the fermentation process of whey wine. A total of 102 volatile flavor substances were detected, with ester being the most abundant. Based on their odor activity values (OAV), 15 important aroma substances, such as ethyl benzoate, ethyl acetate and ethyl butyrate were identified in whey wine. Lactobacillus was the absolutely dominant genus at the early stage of fermentation, while Lactobacillus and Lactococcus became the absolute dominant genera as the fermentation process progressed. Bacterial function prediction showed that the major metabolic activities of whey wine were amino acid metabolism and carbohydrate metabolism. Correlation analysis showed that most flavor substances were positively correlated with Lactococcus and Raoultella. The genera Lactococcus and Raoultella showed a significantly positive correlation with ethyl phenyl acetate, ethyl decanoate, ethyl caproate and ethyl acetate. Lactobacillus was positively correlated with citral, caprylic acid, decanoic acid, 4-ethylphenol, ethyl heptanoate, methyl decanoate and ethyl oleate. This study can provide a theoretical basis for the selection of starter cultures for and the flavor control of whey wine.