Abstract: The aim of this work was to improve the flavor of an enzymatic hydrolysate of Mactra veneriformis by Maillard reaction. The effects of sugar type, mixing ratio and amount of sugars, reaction temperature, time and initial pH on sensory score, the degree of reaction and the color difference were investigated to obtain the optimal reaction conditions. Meanwhile, the changes of free and total amino acids, and volatile compounds before and after reaction were also analyzed. The results showed that all the reaction parameters significantly influence the flavor of the enzymatic hydrolysate (P < 0.05). The optimal conditions of Maillard reaction were obtained as follow: ratio of xylose to glucose 1:2, 4.0% reducing sugar, initial pH 6.5, temperature 100 ℃ and time 90 min. The Maillard reaction resulted in loss of all 18 amino acids especially alanine, glycine, taurine and glutamic acid followed by histidine, arginine, methionine, phenylalanine, leucine and lysine in the hydrolysate, indicating that these amino acids may take part in the Maillard reaction and contributed to the flavor of reaction products. The species and relative contents of flavor components were different after the Maillard reaction. The contents of aldehydes, ketones and esters increased, while those of hydrocarbons decreased.

Key words: Mactra veneriformis, enzymatic hydrolysate, Maillard reaction, flavor improvement