Amino acid catabolism plays a major role in cheese aroma development. Previously, we showed that the lactococcal aminotransferases AraT and BcaT initiate the conversion of aromatic amino acids, branched-chain amino acids and methionine to aroma compounds. In this study, we evaluated the importance of these two enzymes in the formation of aroma compounds in a cheese model by using single araT and bcaT mutants and a double araT/bcaT mutant. We confirmed that addition of ¿-ketoglutarate, a co-substrate of aminotransferases, stimulates the conversion of amino acids to aroma compounds in cheese. The results demonstrated that AraT and BcaT are essential for conversion of aromatic and branched-chain amino acids to aroma compounds by Lactococcus lactis in the cheese model and that they also play a major role in the formation of volatile sulphur compounds from methionine. However, another pathway or another aminotransferase appears also to be weakly involved in the formation of these sulphur compounds.
- cystathionine beta-lyase
- lactis subsp
- flavor development
- semihard cheese
Rijnen, L., Yvon, M., van Kranenburg, R., Courtin, P., Verheul, A., Chambellon, E., & Smit, G. (2003). Lactococcal aminotransferases AraT and BcaT are key enzymes for the formation of aroma compounds from amino acids in cheese. International Dairy Journal, 13(10), 805-812. https://doi.org/10.1016/S0958-6946(03)00102-X