Dynamics of free amino acid composition in cheese ripening

Characteristic changes in composition of free amino acids in cheese during ripening were studied. Semi-hard cheeses with a variation in fat and moisture were analysed. The Danish cheeses Samso and Danbo with relatively high moisture content and short ripening (2-3 months), kept a constant composition of amino acids from some weeks until the end of ripening. In the Swedish cheese Herrgard, with lower moisture content and longer ripening (7 months) the amino acid composition changed in a characteristic way during ripening. The relative amount of Lys and Pro increased, while that of Leu and Phe decreased, reflecting overproduction of Lys and Pro due to aminopeptidase availability, and microbial catabolism of Leu and Phe that may produce cheese flavours. Similar effects were obtained in Samso and Danbo by adding Lactobacillus helveticus as adjunct. The ratio of Orn to Cit was related to the number of viable and dead starter cells.