What You Need to Know
During the koji stage, Aspergillus oryzae produces proteases, amylases, and glucosidases that hydrolyze proteins and starches, generating peptides and sugars. In the brine stage, proteolysis and Maillard reactions produce umami nucleotides such as 5′‑IMP and 5′‑GMP, while the acidic environment and high salt concentration drive flavor development and microbial stability.
The Science
Primary Reaction
Proteolysis and Maillard reactions leading to umami nucleotides and flavor compounds