Flavor changes by heating foods are due to many reactions that occur among various components in foods. Among the reactions, the Maillard reaction of sugars with proteins (amino acids) significantly contributes to the flavor formation of heated foods. Simple Maillard model systems consisting of a sugar and an amino acid form varieties of flavors which are mainly changed by a class of an amino acid. The formation of flavors and volatile chemicals by the Maillard reaction is highly affected by reaction conditions : temperature, duration, water content and pH. The volatile compounds produced by the Maillard reaction include many classes of chemicals : furans, furanones, pyrones, Strecker aldehydes, pyrazines, pyrroles, oxazoles, thiols, thiophenes, thiazoles and cyclic polysulfides. The formation mechanisms of these compounds have been intensively investigated. The Maillard reactions are widely used to produce flavoring materials. These applications are shown in many patents claimed .
