Dynamic changes in volatile flavor substances and microbial communities during fermentation of Chinese Fuyuan pickle

This study investigated dynamic changes in physicochemical properties, organic acids, free amino acids, volatile flavor compounds, microbial succession, and their correlations during the fermentation of salt-free Fuyuan pickle. Significant variations were observed in pH, total titratable acidity, soluble sugars, soluble proteins, lipids, and nitrite. Oxalic acid, succinic acid, and lactic acid continuously accumulated, accompanied by a decrease in total free amino acids. The volatile compounds were mainly alcohols and aldehydes. Sixteen volatile flavor compounds with high odor activity values (OAV>1) contributed fruity, grassy, and fresh aromas and reduced the pungent odor. The predominant genera were Lactococcus, unclassified__Enterobacteriaceae, Lactobacillus, unclassified Dipodascaceae, Plectosphaerella, and Fusarium. Correlation analysis revealed that Lactobacillus, Leuconostoc, Achromobacter, unclassified Dipodascaceae, and Fusarium were strongly correlated with organic acids and free amino acids. Furthermore, Lactobacillus, Leuconostoc, unclassified Dipodascaceae, and Fusarium were significantly positively correlated with key volatile compounds such as 1-hexanol and 1-decanol. Lactococcus was significantly positively correlated with hexanal and heptanal. This study provides insights into quality changes during the fermentation of salt-free Fuyuan pickle and offers a solid basis for the industrial production of salt-free pickles.