Effect of non-core microbes on the key odorants of paocai

Paocai is a widely consumed plant-based fermented food. We studied the effects of microbial community succession and non-core microbes on the key odorants of naturally fermented paocai. Microbiome and molecular sensory science were used to analyze potential relationships between microbial diversity and key flavor compounds. High-throughput analysis pointed out that paocai had a high level of biodiversity, with core microbes mainly represented by Weissella, Lactococcus, and Lactiplantibacillus and non-core microbes mainly represented by Acinetobacter, Raoultella, Enterobacteriales, Debaryomyces, Kazachstania, and Candida species. Ethyl acetate (OAV = 156.84), 1-hexanal (OAV = 76.18) and 1-nonanal (OAV = 57.90) were the key odorants, producing flavors described as etherial, fruity, green, and aldehydic. A total of 57 bacterial strains and 36 fungal strains were isolated and identified from paocai. A Spearman correlation analysis and in vitro simulation system comprehensively analyzed to the correlation of the microbial community and key flavors metabolism characteristics. Bacteria in non-core microbes are not conducive to the quality and safety of paocai, while yeast have the characteristics of “low quantity and great influence” on the key odorants of paocai. These findings will help elucidating the role of non-core microbial community plays in spoilage as well as flavor formation of paocai.