关键词: 高通量测序, 多元统计分析, 有机酸, 浙江玫瑰醋, 相关性分析

Abstract: During the natural fermentation process of Zhejiang rosy vinegar, alcoholic and acetic acid fermentation of saccharified cooked rice starch with microorganisms in the air took place after water addition. This study revealed the composition and diversity of the bacterial community and changes in organic acid contents during the fermentation process of rosy vinegar. The V4 region of the bacterial 16S rRNA gene from rosy vinegar was subjected to Illumina MiSeq high-throughput sequencing and organic acid contents of rosy vinegar were determined by high performance liquid chromatography (HPLC). Furthermore, the correlation between organic acid contents and relative bacterial abundance was investigated by using bidirectional orthogonal partial least squares (O2PLS) analysis. The results showed that Acetobacter and Lactobacillus dominated the bacterial community after water addition and the total relative abundance was higher than 80%. Organic acid contents gradually increased as the fermentation proceeded, with the most abundant being acetic acid and lactic acid. Using hierarchical cluster analysis (HCA) and principal component analysis (PCA), vinegar samples at the early, middle and late stages of fermentation were clearly distinguished based on organic acid contents, and organic acid composition was significantly different among vinegar samples. Through the correlation analysis a total of 23 bacterial genera with VIP(pred) greater than 1 were obtained, including Acetobacter, Lactobacillus, and Methylobacterium. In addition, a heatmap for the correlation between bacteria with VIP(pred) > 1 and organic acids was established, and the bacteria with correlation coefficients |ρ| > 0.6, indicating high correlation, were obtained. This study provides supporting data for finding functional microorganisms involved in the fermentation process of rosy vinegar and improving the quality of rose vinegar.

Key words: high throughput sequencing, multivariable statistical analysis, organic acids, Zhejiang rosy vinegar, correlation analysis