Proteolysis and Lipolysis of Goat Milk Cheese

Abstract

Numerous varieties of goat milk cheeses are produced worldwide. Maturation or ripening of goat and other species milk cheeses is governed by interplay of many different factors. Proteolysis and lipolysis are two major biochemical processes in the multifaceted phenomenon of cheese aging, which involves a variety of chemical, physical, and microbiological changes under controlled environmental conditions. Proteolysis of cheeses in general is influenced by several factors including plasmin, chymosin, protease from starter and nonstarter bacteria, pH and moisture levels of the curds, storage temperature and time, salt content, salt-to-moisture ratio, and humidity. Primary factors affecting lipolysis in cheeses are fatty acid composition, lipolytic enzymes, lipolytic microorganisms, moisture, temperature, storage time, oxygen, and surface area, etc. Several analytical techniques have been used to measure proteolysis of goat and (or) cow milk cheeses during ripening, such as solubility of peptides and amino acids in various solvents or precipitants, liberation of reactive functional groups, various forms of chromatography, and different forms of electrophoresis. Lipolysis of goat milk cheeses has been estimated by acid degree value (ADV), acid value, and free fatty acid concentration, while lipid oxidation of dairy goat products can be determined by peroxide value, thiobarbuturic acid value (TBA). Recent reports have shown that goat cheeses had greater rates of protein degradation than cow counterparts, and that aging time and temperature synergistically elevated most of proteolytic and lipolytic indices in goat cheeses. This paper will further discuss proteolytic and lipolytic characteristics of goat milk cheeses.