A Comparison of Color Formation and Maillard Reaction Products of a Lactose−Lysine and Lactose−N α-Acetyllysine Model System

The formation of color and Maillard reaction products in two model systems consisting of lactose and lysine or N α-acetyllysine has been investigated. During heating, the blockage of the Nα group of lysine determined a faster color and antioxidative ability development compared to the system with free lysine. This is combined to a greater amount of melanoidin formation in the acetylated lysine system, while in the free lysine system a higher amount of pyrraline and hydroxymethyl furfural were detected. The pattern of low molecular weight products suggests that 3-deoxyglucosone and 1-deoxyglucosone degradation pathways are favored for free lysine and N α-acetyllysine, respectively. Whole data allow us to hypothesize that in a lactose−N α-acetyllysine model system the formation of colored high molecular weight polymer proceeds faster because less material is dispersed in reaction pathways, mainly the Strecker degradation, which leads to small and intermediate molecular weight products. Keywords: Maillard reaction; lactose; N α-acetyllysine; antioxidative efficiency; melanoidins; color; LC−MS