The Flavor, Volatile Acidity, and Soluble Protein of Cheddar and other Cheese

Abstract

The method of manufacturing Cheddar cheese has been known for many generations. About 50 years ago scientists began an intensive study of the factors affecting the flavor of this cheese with the idea that the source and identity of the flavoring substances could be established. Although much scientific knowledge has been accumulated from these studies, the specific flavoring materials are still unknown. The present trend toward the manufacture of Cheddar cheese from pasteurized milk has accentuated the need for this knowledge, as pasteurized milk cheese has less flavor and slightly different characteristics than that found in raw milk cheese. The literature is voluminous and only a few references will be cited. The fundamental chemical changes that occur during the ripening process as known in 1891 were stated by Van Slyke (17). He wrote that there was a slow evolution of carbon dioxide from the casein or fat, or both. Volatile and nonvolatile fat ty acids developed from the fat. The nitrogen compounds, especially casein, broke down into soluble compounds, some eventually becoming ammonia. Cured cheese was more alkaline than fresh cheese. The formation of the free fat ty acids was the principal chemical change during ripening. Van Slyke, Harding, and Hart (18) concluded from their study of rennet that this enzyme did not decompose protein into compounds that produced flavor in cheese. Suzuki, Hastings, and Hart (16) studied the origin and composition of steam disti]clate from cheese which contained the flavor compounds. They found bacteria to be the principal ripening agent. The lactose disappeared from cheese in 3 to 6 days but some of the lactates were fermented into volatile fa t ty acids, especially acetic and propionic. Butyric and caproic acids were deri.ved from the fats and proteins. Succinic acid, alcohols, and esters also were present in the steam distillate. Improved Cheddar cheese flavor has been reported with special cultures in Cheddar cheese making in addition to the usual lactic starter. Hucker and lVIarquardt (7) found that a Streptococc~s paracitrovorus culture used with Hansen's commercial starter produced characteristic cheese flavor of superior quality from pasteurized milk. Proteolytic coccus cultures produced bitter flavor, as did the culture of S. paracitrovorus when used without starter. Hansen, Bendixen, and Theophilus (3) confirmed that cheese