Plasmin Protease Enzyme
Plasmin protease enzymes present in whey ingredients may lead to improved texture in yogurt or better flavor and texture in natural cheese.The enzymes, which originate in bovine blood, may also have negative effects, such as decreasing the water binding capacity of processed meats and producing undesirable textures in pasteurized processed cheese.
The research showed that commercial whey protein isolates generated by ion-exchange separation tend to have the lowest plasmin levels. Protein concentrates from sweet whey (rennet coagulated curd) have intermediate amounts, and the highest levels occur in concentrates from acid whey (produced by acid precipitated cheese curds).
Although bacterial growth during raw milk storage decreases the plasmin content in the casein portion (i.e., cheese curd) and increases the content in whey, whey separation methods have an even more profound effect.