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 fermented 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 Lactobacillus positevely correlated with H-fluorendimethyl, octenol, and benzaldehyde. These findings helped in understanding the formation of volatile flavoring compounds during SP fermentation. • Amino nitrogen and reducing sugar contents obviously increased with fermentation. • Glutamate and aspartate were the dominant amino acids in SP sample. • Enterobacter, Bacillus and Staphylococcus were the dominant bacterial genus. • High relative contents of aldehyde and heterocyclic compounds were detected in SP. • Bacillus and Staphylococcus were correlated with aldehydes, esters and alcohols.