Some changes in the constituents upon heating a model meat flavour system

Percentage changes in the amino acid content upon heating with different components in a synthetic model meat flavour mixture were followed during different stages in development of the system. Heating of ten different amino acids with a simple sugar mixture (glucose, ribose and xylose) resulted in losses of approximately 95, 58, 38 and 37% of the cysteine, methionine, leucine and isoleucine, respectively, whereas the other amino acids decreased by 19–31%, but the ammonia (NH₃) content by only 5%. On heating gelatin with the simple sugar mixture, tyrosine and phenylalanine losses amounted to about 58 and 40%, respectively, while the other amino acids declined by 27–37% and the NH₃ content by some 12%. Heating of the composite model system (gelatin, added amino acids and simple sugars) resulted in losses of about 94, 60 and 55% of the cysteine, methionine and histidine, respectively, while the other amino acids decreased by 20–35% and the NH₃ content by 15%. The possible role of some of the amino acids in the development of the synthetic meat flavour system is discussed in view of these findings.