Analysis of the microbial community structure and flavor components succession during salt‐reducing pickling process of <i>zhacai</i> (preserved mustard tuber)

Abstract

The salt-reducing pickling method has been applied to the industrial production of <i>zhacai</i>. In order to reveal the succession of the microbial community structure and flavor components during the pickling process, this study used PacBio Sequel to sequence the full length of 16S rRNA (bacteria, 1400 bp) and ITS (fungi, 1200 bp) genes, and detected flavor components simultaneously, including organic acids, volatile flavor components (VFC), monosaccharides, and amino acids. Eleven phyla and 148 genera were identified in the bacterial community, and 2 phyla and 60 genera in the fungal community. During the four stages of pickling, the dominant bacterial genera were <i>Leuconostoc</i>, <i>Lactobacillus</i>, <i>Leuconostoc</i>, and <i>Lactobacillus</i>, while the dominant fungal genera were <i>Aspergillus</i>, <i>Kazachstania</i>, <i>Debaryomyces</i>, and <i>Debaryomyces</i>, respectively. There were 32 main flavor components (5 organic acids, 19 VFCs, 3 monosaccharides, and 5 amino acids). Correlation heat mapping and bidirectional orthogonal partial least squares (O2PLS) analysis showed that the flora having close relation to flavor components included 14 genera of bacteria (<i>Leuconostoc</i>, <i>Clostridium</i>, <i>Devosia</i>, <i>Lactococcus</i>, <i>Pectobacterium</i>, <i>Sphingobacterium</i>, <i>Serratia</i>, <i>Stenotrophomonas</i>, <i>Halanaerobium</i>, <i>Tetragenococcus</i>, <i>Chromohalobacter</i>, <i>Klebsiella</i>, <i>Acidovorax</i>, and <i>Acinetobacter</i>) and 3 genera of fungi (<i>Filobasidium</i>, <i>Malassezia</i>, and <i>Aspergillus</i>). This study provides detailed data regarding the microbial community and flavor components during the salt-reducing pickling process of <i>zhacai</i>, which can be used as a reference for the development and improvement of salt-reducing pickling methods.