Color Development Kinetics of Maillard Reactions

Maillard reactions have been reported extensively. However, full color development kinetics of Maillard reactions have rarely been studied in detail. This study systematically investigated the color development kinetics of Maillard reactions. Thus, arginine (Arg), histidine (His), and lysine (Lys) were each reacted with dihydroxyacetone (DHA) using a simplified model system at different molar ratios, reaction times, pH, and temperatures. Importantly, the browning intensity (at 450 nm) and full color characteristics (within CIE L*a*b* color space) were measured and analyzed in detail. Minitab statistical software was employed to design the factorial experiments and analyze the main and interaction effects. It was found, for the first time, that His and Lys reacted with DHA more rapidly than Arg, and the difference was obvious with the increase of molar ratio and reaction time, reflected in the change of b*. pH 6.2 and higher temperature favored the formation of deeper colored products in amino acid–DHA, accompanied by reduced lightness (L*), significant loss in yellow hues (+b*), and shift toward red hues (+a*). The greatest browning intensities of Arg–DHA (A450 = 0.63), His–DHA (A450 = 1.12), and Lys–DHA (A450 = 1.18) were achieved at molar ratio = 3, 72 h, pH 6.2, and 50 °C, with corresponding L*, a*, and b* values being 54.51, 14.03, 42.75; 48.26, 47.28, 13.59; and 43.35, 53.64, 10.82, respectively.