Lipase Activity during Making and Ripening of Cheddar Cheese

Abstract

Milk lipase is absent in raw milk Cheddar cheese 24 hrs. after the start of making. It disappears mainly during the heating of the milk coagulum at 96-104 [degree]F for 55 min. and during removal of whey. Even if present, milk lipase, inactive below pH 6.5, could not act in Cheddar cheese (pH5.-5.4). Milk has no lipolytic activity at pH 5. The addition of rennet during Cheddar cheese-making causes the appearance of lipolytic activity at pH 5 which completely disappears at the time of whey removal. After a 5 to 20 day ripening period, cheese lipases are found in Cheddar cheese. The lipolytic activity at pH 5 present during cheesemaking is very small compared to the cheese lipase activity found in the ripening cheese. The bacterial flora of the cheese is probably the source of cheese lipases. Cheese lipase is set free mainly between the 5th and 100th day of ripening. It can be detected in larger amts. in 5- to 25-day-old pasteurized milk Cheddar cheese than in corresponding raw milk cheese. After 30 days, the cheese lipase content of pasteurized milk Cheddar cheese is < 1/2 that of corresponding raw milk cheese.