Effect of lysine on the cysteine-xylose Maillard reaction to form flavor compounds.

To understand flavor formation mechanisms in complex meat-like Maillard systems, effect of lysine on cysteine-xylose reaction to form flavors was studied. GC-MS and GC-O analyses found lysine of 1 times cysteine concentration led to the greatest amount of sulfur-containing meaty compounds while more additional lysine caused more pyrazine compounds. LC-MS analysis showed lysine competed with cysteine to form the early-stage intermediate of Lys-Amadori compounds and accelerated conversion of 2-threityl-thiazolidine-4-carboxylic acids to Cys-Amadori compounds from the cysteine-xylose reaction. Reaction rates based on UV 294 and 420 nm absorbance, browning color, and consumption of cysteine and xylose suggested addition of lysine continuously accelerated the Maillard reaction at intermediate and final stages. Pearson correlation analysis revealed less reaction rates and Lys-Amadori compounds formed could cause more meaty compounds and thereby exposed formation pathways of important aroma compounds. This work can provide guidance for optimizing meat or meat product composition to improve meat flavor.