Enhancing beef flavor profiles via Maillard reaction of γ-Glutamylated beef protein hydrolysates and xylose

Beef protein hydrolysates (BH) and their gamma-glutamylated products (gamma-BH and gamma-GBH, 0 and 7 % L-Gln extraaddition) were prepared, followed by xylose-induced Maillard reaction. Maillard reaction products (MRPs) of gamma-glutamylated products (gamma-BH-MRP and gamma-GBH-MRP) showed a higher degree of Maillard reaction and improved sensory characteristics (p < 0.05). Specifically, UV absorbances and fluorescence intensity of MRPs significantly increased (p < 0.05), and there were significant increases in kokumi, umami, saltiness, roast, and meaty flavors, and a reduction in bitterness (p <0.05) after gamma-glutamylation. In gamma-BH-MRP and gamma-GBH-MRP, the relative content of most flavor compounds increased significantly (p < 0.05), especially pyrazines and furans, and 8 and 10 new flavor compounds were also detected. 7 and 25 new gamma-glutamyl peptides were identified, with their contents ranging 2.26-8.38 mu M and 1.93-71.90 mu M, respectively. These data illustrate that gamma-glutamylation can promote the formation of MRPs, thereby improving the flavor characteristics of beef flavorings.