Chemistry of Maillard Reactions: Recent Studies on the Browning Reaction Mechanism and the Development of Antioxidants and Mutagens

Abstract

In this chapter, the browning reaction mechanism, and the formation of antioxidants and mutagens are reviewed. The stages in browning reaction mechanism based on Hodge's scheme are described in detail. Different stages are initial stage involving the formation of glycosyl amino products followed by Amadori rearrangement, intermediate stage involving dehydration and fragmentation of sugars and final stage involving aldol condensation, polymerization, and formation of heterocyclic nitrogen compounds. Formation of free radicals and structure of novel free radicals in the initial stage are described in detail. The sugar fragmentation and carbonyl compounds in the formation of free radicals are effective in browning process. The steps in the intermediate stages described are Amadori rearrangement products, enolization and degradation of Amadori products and precursors of melanoidins. The final stage describes the chemistry of melanoidins. The chapter also discusses the antioxidants and Maillard reaction. The stability of foods increases when Maillard reactions occur. The stabilization is considered to be because of the antioxidative action of Maillard reaction products (MRPs). Conditions for induction of antioxidative activity are explained. Detailed explanation about the antioxidative property of reductones is presented. The antioxidative property of reductones is due to their reducing activity and metal cheating ability. Application of MRPs in practical food processing is also highlighted. The relationship between mutagen formation and browning of food is explained. The role of nitroso mutagens and antimutagens is also discussed. The chapter also discusses the need for more detailed information on the structure and properties of melanoidin to elucidate the mechanism of its antioxidative activity.