Inhibitory effect of sulfur-containing amino acids on burnt off-flavours in canned liver sausages.

The sensory quality of canned liver sausages is limited by a negative burnt high-temperature-heated flavour, caused by Maillard reaction products between amino acids and sugars. In experiments with liver sausage, reduced glutathione in concentrations of 0.01-0.30% had no positive effect on taste and color. N-acetyl-L-cysteine, an acylated derivative of the amino acid L-cysteine, was tested in concentrations between 0.03-0.50%; a concentration of 0.15% was optimal for the inhibition of the burnt flavour. An acid taste caused by lower pH was corrected by the addition of 0.25% diphosphate. When 0.15% N-acetyl-L-cysteine and 0.25% diphosphate were added to the sausage preparations, the heat-induced changes in amino acids and glucose were the same as in the control. Moreover, under different sterilization conditions, the additive mixture was shown to be an excellent inhibitor of the burnt flavour.