Biochemistry of Cheese Ripening

Abstract

It is during ripening that the flavour and texture characteristic of the cheese variety develop. Three major pathways constitute the biochemistry of cheese ripening: (1) metabolism of residual lactose and of lactate and citrate, (2) lipolysis and fatty acid metabolism and (3) proteolysis and amino acid catabolism. Cheese ripening is mediated by metabolically active cells from the starter, non-starter and adjunct starter microbiotas and enzymes that contribute to ripening come from the coagulant (principally chymosin but sometimes other proteinases, and in cheeses made using rennet paste, also pregastric esterase), milk (plasmin, somatic cell enzymes and lipoprotein lipase), starter and non-starter lactic acid bacteria (cell envelope-associated proteinases and a wide range of intracellular peptidases, esterases and amino acid catabolic enzymes) and adjunct starters (proteinases, peptidases and lipases). The primary products of cheese ripening (peptides, amino acids and fatty acids) are metabolized further to volatile flavour compounds through metabolism of fatty acids and amino acid catabolism.