Role of amino acids and glucose in development of burnt off-flavours in liver sausage during heat processing.

The effect of amino acids and glucose on the development of burnt off-flavours was investigated in meat model systems for liver sausage. At a constant glucose concentration, the burnt flavour was intensified by addition of an amino acid mixture. In a batter without liver, the development of burnt off-flavours, similar to those in liver sausage, could be induced through addition of exogenous amino acids and glucose. The endogenous amino acids from liver reacted more intensely than the exogenous amino acids in the formation of the burnt flavour components. After heating batches with added exogenous amino acids and glucose the free amino acid contents (73-89% of initial content) were higher than in batches to which liver was added (42-53% of initial content). The differences in the free amino acid content of glycine, glutamic acid and threonine were linearly related to the intensity of burnt flavour. Results indicate that burnt flavour is due to the Maillard reaction.