What You Need to Know
During fermentation, Aspergillus oryzae secretes proteases that hydrolyze soy proteins into peptides and free amino acids, while Bacillus subtilis contributes amylases and further proteolytic activity. Lactic acid bacteria lower the pH to 4.5–5.5, inhibiting pathogens and promoting the formation of volatile sulfur compounds such as 2‑acyl‑4‑methyl‑5‑thiazole. The resulting glutamic acid imparts umami, and isoflavone aglycones are released, enhancing antioxidant activity.
The Science
Primary Reaction
Enzymatic hydrolysis of soy proteins by Aspergillus oryzae and Bacillus subtilis, followed by acidification by lactic acid bacteria