Mljekarstvo (Oct 2001)
Bitter taste – cheese failure
Abstract
Bitter taste is serous and very often cheese failure in modern cheesemaking process. In this paper the sources and bitter taste development in cheese will be presented. Bitterness in cheese is linked to bitter compounds development during cheese ripening. Most of the bitter compounds come from bitter peptides, the mechanism of theirs development being due to proteasepeptidase system of the cured enzymes and the milk cultures as well as other proteases present in cheese. By the action of curd enzymes, the milk protein - casein - is firstly degraded into high molecular weight compounds possessing no bitter taste. Those compounds are then degraded, by milk protease cultures, to hydrophobic bitter peptides of low molecular weight further degraded, by bacterial endopeptidase during cheese ripening, to bitter peptides and amino acids. In the case when no balance exists, between bitter compounds development and breakdown by lactic acid bacteria peptidase, an accumulation of bitter peptides occurs thus having an influence on cheese bitterness. During cheese ripening naturally occurring milk protease – plasmin, and thermostable proteases of raw milk microflora are also involved in proteolytic process. Fat cheese lipases, initiated by lipase originating from psychrotrophic bacteria in raw milk as well as other cheese lipases, are also associated with bitter taste generation. The other sources of bitterness come from the forages, the medicament residues as well as washing and disinfecting agents. In order to eliminate these failures a special care should be taken in milk quality as well as curd and milk culture selection. At this point technological norms and procedures, aimed to maintain the proteolysis balance during cheese ripening, should be adjusted, thus eliminating the bitter taste of the cheese.
