Characterization of physicochemical properties, microbial diversity and volatile compounds of traditional fermented soybean paste in Henan province of China

This study aimed to investigate the changes in microbial diversity, and volatile compounds of traditional fer-mented soybean paste originated from Henan province of China using 16S rRNA sequencing, headspace solid phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS), and electronic nose (E-nose). The amino acid nitrogen and reducing sugar contents ranged between 1.18 and 1.58 g/100 g and 2.29 and 3.74 mg/g, respectively. The results showed that fermented soybean paste exhibited the highest amount of glutamate and aspartate amino acids. Approximately 112 volatile compounds were detected in all SP samples comprising 10 alcohols, 19 esters, 10 acidic compounds, and 21 heterocyclic compounds. Furthermore, 16S rRNA sequencing indicated that Enterobacter, Bacillus, Staphylococcus, and Enterococcus were the predominant bacteria in fermented soybean paste samples. Moreover, network analysis revealed that Klebsiella, Bacillus, and Lacto-bacillus positively correlated with H-fluorendimethyl, octenol, and benzaldehyde. These findings helped in un-derstanding the formation of volatile flavoring compounds during SP fermentation.

Automated summary

This study investigated changes in microbial diversity and volatile compounds of traditional fermented soybean paste from Henan using various techniques, showing differences in amino acids, reducing sugars, volatile compounds, and predominant bacterial species. The findings help understand the formation of volatile flavoring compounds during soybean paste fermentation.