What You Need to Know
During fermentation, Aspergillus oryzae secretes proteases and amylases that break down soy proteins and starches into free amino acids, peptides, and sugars. The resulting glutamate and other amino acids generate the characteristic umami flavor, while the pH gradually drops from ~6.5 to ~5.5, enhancing flavor development and inhibiting spoilage organisms.
The Science
Primary Reaction
Enzymatic proteolysis and amylolysis by Aspergillus oryzae converting soy proteins and starches into amino acids and sugars