What You Need to Know
The fermentation phase is driven by Bacillus subtilis and Lactobacillus spp., which hydrolyze soy proteins into amino acids and reduce sugars, creating umami and sweetness. During the simmer, Maillard reactions between reducing sugars and amino acids produce melanoidins and other browning compounds, while caramelization of sugars further deepens flavor and viscosity.
The Science
Primary Reaction
Maillard reaction between reducing sugars and amino acids during simmering