Formation of Microbial Lipolysis in Cheese and its Contribution of Flavour to Development

Several biochemical changes occur during the ripening of cheese such as proteolysis and lipolysis. The latter is an important biochemical event during cheese ripening especially in varieties such as Blue and hard Italian cheeses within which an extensive lipolysis occurs. It is due to the presence of lipolytic enzymes called hydrolases (lipases and esterases) cleaving the ester linkage between a fatty acid and the glycerol moiety of the triacylglycerol. These lipolytic enzymes are mainly originated from the mould or other secondary cultures. Lipolytic degradation of triacylglycerol of milk fat during the cheese ripening results in the release of free fatty acids (FFA) that are further catabolised to highly flavoured compounds such as methyl ketones, thioesters and lactones. The major flavour compounds released during the lipolysis are free fatty acids (FFA), directly affecting the cheese flavour and also free fatty acids degradation products directly affecting flavour in different cheeses. In this review, the microbial-based lipolytic agents in cheeses, formation of free fatty acids depending on lipolysis; free fatty acids catabolism products such as metil keton, ester and seconder alcohol and contribution of these compounds to cheese flavour is compiled.