Identification of Polyphenol and Reductone Antioxidants in the Caramelization Product of N-Acetylglucosamine

Caramelization is a nonenzymatic browning reaction of saccharides that occurs under thermal treatment. In this study, the radical scavenging activity of the thermal reaction products (caramels) from three modified hexoses [fucose, galacturonic acid, and N-acetylglucosamine (NAG)] was evaluated. These three caramelization products showed more potent activity than that of the thermal reaction product from glucose, with the most significant activity observed in the product of NAG. A polyphenol and a reductone were detected as noticeable radical scavengers in the caramel of NAG. Subsequently, their radical scavenging activity and antioxidant activity against lipid oxidation were measured to reveal that the identified polyphenol had a superior antioxidant activity to that of Trolox.