Flavor profile and peptide formation in soy sauce fermented from soybean meal by Aspergillus oryzae and Aspergillus Niger

To provide a novel strategy for the development of soy sauce with an improved flavor profile but without gluten, soybean meal was employed as the sole material for fermentation by Aspergillus niger and Aspergillus oryzae. SEM, FTIR, GC–MS, peptide omics and molecular docking were used to analyze flavor characteristics and flavor peptide formation in different combinations. The Aspergillus niger and Aspergillus oryzae groups stand out and presented 3.62-fold increases in alcohol, phenol, and ketone contents in soy sauce compared with Aspergillus oryzae alone; the contents of umami and sweet free amino acids increased by 12.66 %, with the highest content compared with Aspergillus niger; furthermore, Aspergillus niger promoted a 173.7 % increase in the Pro content of the soy sauce compared with Aspergillus oryzae alone, which influenced the amino acid distribution and overall flavor. Thus, the cofermentation of Aspergillus niger and Aspergillus oryzae provides an option for the development of soy sauce.