Enzyme
Japanese: 酵素（エンザイム）
A protein that accelerates chemical reactions in living organisms. Acting as a catalyst, it breaks down or synthesizes specific substances without being consumed itself—the key player in every stage of fermentation.
An enzyme is a biological catalyst. It drives chemical reactions at extraordinary speed while remaining unchanged itself—a property that underpins the entire process of fermentation.
Consider miso-making: the protease produced by koji mold breaks down soybean protein into amino acids, while amylase converts rice starch into sugars. Much of what we perceive as umami and sweetness is the result of enzymes dismantling raw materials.
Each enzyme exhibits substrate specificity, catalyzing only one type of reaction. This precision is what gives fermented foods their complex, layered flavors.