The Use of Steapsin in the Manufacture of Blue Cheese

Blue cheese made from normal cows' milk, even under the most favorable conditions, must be held approximately six months before enough of the characteristic flavor has developed for the cheese to be marketable.The length of the ripening period is a serious deterrent to extensive commercial manufacture of the cheese in this country.Since the work of Currie (1) fat hydrolysis by a water-soluble lipase produced by the mold, Penicilliu~n roqueforti, has been considered the chief factor in the development of the typical flavor of Roquefort-type cheeses.Lane and Hammer (2) were able to shorten the ripening period by homogenization of the milk from which the cheese was manufactured.They attributed the quicker ripening of homogenized milk cheese to the natural milk lipase, the action of which is accelerated by homogenization.They found it necessary to homogenize the milk at temperatures below 115 ° F. if the benefits of homogenization in shortening the ripening period were to be realized to the fullest extent.This is compatible in some respects with the work of Sharp and de Tomasi (3) showing that non-lactic acidity and bitterness did not develop in cream if the milk before separation was flash heated to 110 ° F. (43.3 ° C.).It was found, however, that if the cream was homogenized the milk had to be heated to 140 ° F. (60 ° C.) in order to prevent the lipase action in the cold cream.Various investigators have shown that the ripening of cheese of the Cheddar type could be hastened by increasing the anmunt of rennet used.Orla-Jensen (4) found that in Emmental cheese, trypsin caused much more rapid proteolysis than either pepsin or galactase.Wojtkiewicz and Inikkoff (5) attempted to hasten the ripening of cheese by adding pepsin, trypsin, erepsin and rennet separately and in various combinations, l~ennet and trypsin were found to hasten the ripening of the cheese.The cheeses to which trypsin was added had a bitter flavor.Better results, from a flavor standpoint, were secured when pepsin was added in combination with trypsin, although some bitterness was evident.Freeman and Dahle (6) experimenting with the ripening of Cheddar cheese found that additional amounts of pure rennin increased the rate of proteolysis.This was also true for pepsin, particularly at the beginning of the ripening period, and an aged product with an appreciably higher flavor score was obtained.Trypsin