What You Need to Know
During the koji stage, Aspergillus oryzae secretes amylases and proteases that hydrolyze starches and proteins into sugars and amino acids. The subsequent brine fermentation by lactic acid bacteria and yeast converts sugars into lactic acid, ethanol, and a complex mixture of amino acids and nucleotides that contribute to umami.
The Science
Primary Reaction
Starch and protein hydrolysis by Aspergillus oryzae followed by lactic acid and ethanol fermentation by lactic acid bacteria and yeast