Characteristics of microbial communities in fermentation of pickled ginger and their correlation with its volatile flavors

The effects of natural fermentation and inoculation fermentation on the volatile flavor substances of pickled ginger was studied. High-throughput sequencing and gas chromatographic-mass spectrometry were used to measure the bacterial community changes and its flavour compounds during one to six days’ fermentation. First, 55 and 51 volatile compounds were detected in the natural and the Lactiplantibacillus plantarum-inoculated fermentation samples, respectively. Alkenes, alcohols, aldehydes and esters were the main volatile components of both types of fermented ginger, but their contents were different. Then, 40 and 43 bacterial genera were detected in the natural and inoculation fermented gingers, respectively, including 15 major bacterial genera such as Lactobacillus. However, the abundance of bacterial genera in the samples was different. The correlation analysis showed that a total of 43 bacterial genera had medium to high correlations with 49 volatile flavor compounds (|ρ|> 0.6), including one aldehyde, two ketones, five esters, nine alcohols and 32 olefins. The comprehensive results showed that, compared with natural fermentation, inoculation fermentation could change the abundance of bacteria in pickled ginger, thereby improving the volatile flavor compounds of this popular product.