摘要 : Characteristic flavour of different cheese varieties is the result of a balanced breakdown of milk components including fat, casein, lactose and citrate. Several compounds are present in different varieties; while the proportion b... 展开 Characteristic flavour of different cheese varieties is the result of a balanced breakdown of milk components including fat, casein, lactose and citrate. Several compounds are present in different varieties; while the proportion between them varies characteristically, only some compounds are exclusive for specific cheeses. The flavours result from activities of a changing microflora during ripening. This review describes the bacterial influence on flavour formation in semi-hard to hard cheese varieties with eyes, and which are made with mesophilic DL-starter. Influence of starter and non-starter lactic acid bacteria is described, as well as of propionic acid bacteria and thermophilic lactobacilli. Potent flavour compounds include amino acids, especially glutamic acid, umami and bitter peptides, ethyl esters of acetic and propionic acid from metabolism of lactose and larger carboxylic acids from fat catabolism, which also contributes to formation of methylketones and secondary alcohols. Diacetyl and acetoin are produced from citrate by DL-starter bacteria but also from aspartic acid by e.g. non-starter bacteria. Several aroma compounds are derived from branched-chain, aromatic and sulphur amino acids. The total amount of aroma compounds typically increases during ripening, however, the amounts of secondary alcohols for example, may decrease while their corresponding methylketones increase during a long-time ripening. Thermophilic lactobacilli may intensify taste and stimulate metabolism of other bacteria by increasing release of amino acids. Propionic acid bacteria contribute specifically, along with propionic acid and its ethyl esters. Non-starter lactobacilli have been shown to have the potential to increase formation of aroma compounds from amino acid catabolism. 收起