Tyrosinase

Tyrosinase is an enzyme that oxidizes the amino acid tyrosine to produce pigments. It is involved in browning reactions, particularly in koji and sake lees (sake kasu), and can affect the color and flavor of sake. Specifically, during the saccharification process of koji and during fermentation, tyrosinase can act to produce a brownish tint. This phenomenon can also have a certain influence on the quality of the sake, and in what is known as black lees (kurokasu), a darker color is characteristic. The action of tyrosinase plays an important role in the sake brewing process.