Correlation between microbial communities and volatile flavor compounds in the fermentation of new pickle fermentation broth

The correlation between microbial community succession and volatile flavor substance changes in the fermentation of new pickle fermentation broth was revealed in this study via high-throughput sequencing and gas chromatography-mass spectrometry (GC-MS). Microbiological analysis demonstrated that Lactobacillus (relative abundance ≥93.98%) was the dominant bacterial genus in the broth, whereas Enterobacter was richest only in the first sampling. E-nose and GC-MS inspections revealed that the types and contents of volatile flavor compounds increased continuously with fermentation, rising from 27 volatile flavor compounds in the first sampling to a maximum of 62 species, with the content increasing from 8.686 μg/mL to 106.083 μg/mL. Olefins and alcohols had the highest proportions throughout the fermentation process. The Spearman correlation coefficient revealed that 77 volatile flavor compounds and 22 bacterial genera had medium-high correlations (|ρ| >0.6). Lactobacillus (Gen1), the most dominant genus, was significantly positively correlated with 21 volatile compounds (ρ > 0.6), including myrcene (Ole7), terpinene (Ole12) and ocimene (Ole1), but negatively associated with 13 volatile compounds (ρ < -0.6), including 5-methyl-4-nonene (Ole5l), anisole (Ole26) and 2-octen-4-one (Ket6). Thus, this study may provide a theoretical basis to improve the flavour and overall quality of the new pickle fermentation broth.