A Study of the Ripening of Dariworld and Cheddar Cheese with Special Emphasis on Proteolysis

Abstract

Summary Smooth, waxy consistency and desirable processing characteristics develop more rapidly in Dariworld than in Cheddar cheese. Measurements of soluble nitrogen and formol nitrogen were made of both varieties during 5 mo. of ripening to learn if rates of proteolysis might explain these differences in consistency. Observations were made at five different stages of ripening on two lots of each variety, one lot of which was normal and the other abnormally high in pH. Rates of proteolysis were essentially alike in the normal lots of both varieties and in the Cheddar with high pH. The sweet Dariworld which, unlike the sweet Cheddar, retained its high pH during ripening, showed the most rapid and extensive protein decomposition. Both of the sweet lots, however, were hard and woody in consistency and did not improve as amounts of soluble nitrogen and formol nitrogen increased during ripening. Acidity developed in making the sweet modifications evidently was insufficient to effect normal partition of minerals between whey and curd, and the resulting abnormal composition of curd apparently caused the defects in body. Rapid loss of curdiness in the ripening of normal Dariworld was not caused by unusually fast protein breakdown. Physico-chemical changes caused by the prolonged exposure of the curd to sodium chloride brine during the making operation of this cheese and the relatively high moisture content evidently account for its characteristic consistency.