Volatile Compounds Generated from the Maillard Reaction of Pro-Gly, Gly-Pro, and a Mixture of Glycine and Proline with Glucose

A wide variety of peptides have been reported to be present in food systems and have been recognized as important flavor compounds. However, aroma generation characteristics of peptides have not been studied to an appreciable extent. The present paper reports the generation of aroma compounds from a model system consisting of dipeptides Gly-Pro, Pro-Gly, and Gly plus Pro as the amino sources and glucose as a reducing sugar. The Gly-Pro dipeptide generated a larger amount of pyrrolizine and pyridine volatile compounds than the Pro-Gly dipeptide. The pyrrolizines were generated at lower temperature than either pyrazines or pyridines. At lower temperature of 130 °C, the glycine plus proline system produced primarily pyrrolizines but no pyrazines. At elevated temperature (180 °C), the pyrrolizines and pyrazines were formed in equal abundance.