Reduction
Japanese: 還元
The reverse of oxidation. A reaction in which a substance loses oxygen or gains electrons, proceeding in tandem with oxidation in fermentation.
Reduction is the mirror image of oxidation—a reaction in which a substance loses oxygen or gains electrons. In chemistry, oxidation and reduction always occur simultaneously: when one substance is oxidized, another is inevitably reduced.
Fermentation is a chain of these redox reactions. In alcoholic fermentation, glucose is oxidized to pyruvic acid, which is then reduced to ethanol. Microorganisms derive their energy from this exchange of electrons.
Invisible electron transfers create the sensory experience we call flavor. Reduction reactions carry half of that unseen mechanism.