What You Need to Know
The process begins with inoculation of steamed soybeans and roasted wheat with Aspergillus oryzae, followed by a 15–20 % NaCl brine. Proteolytic enzymes released by the mold hydrolyze proteins into peptides and free amino acids, while Maillard reactions between reducing sugars and amino acids generate volatile flavor compounds such as 4‑methyl‑2‑pyridone and 3‑methyl‑2‑pyridone. The resulting mixture of peptides, nucleotides, and volatile compounds imparts the characteristic umami, salty, and sweet notes of soy sauce.
The Science
Primary Reaction
Solid‑state mold inoculation followed by liquid brine maturation, leading to enzymatic hydrolysis and Maillard reactions