Color characteristics and pyrolysis volatile properties of main colored fractions from the Maillard reaction models of glucose with three amino acids

The effects of hydrosoluble colored fractions generated in the Maillard reaction models on the volatiles of pyrolytic Maillard reaction products was investigated. The hydrosoluble colored fractions obtained by reaction of glucose with glycine (Gly-Glc), proline (Pro-Glc) and phenylalanine (Phe-Glc) respectively at 125 degrees C were separated using Sephadex LH-20 Gel column. The colored fraction with large molecular weight had a higher contribution to the overall color and more glucose residue structures in main skeleton than that with small molecular weight in the same model. Gel permeation chromatography analysis indicated that these colored fractions had continuous relative molecular weight distribution (1000-80000 Da). Pyrolysis - gas chromatography - mass spectrometry determination (pyrolysis temperature: 160 similar to 900 degrees C) suggested that furans and pyrroles were the main volatiles of two Gly-Glc fractions after pyrolysis, and the key pyrolysis volatiles of Pro-Glc fraction were furans, pyrroles, pyran, indole and cyclopentenes, which gave a freshly baked bread, nutty, coffeelike and sweet caramel-like odor. Especially phenyl-containing compounds seemed typical indicators of Phe-Glc fraction pyrolysis products, exhibiting a benzene-like, tallowy, sweet, balsamic and floral odor. The hydrosoluble colored fractions produced by different Maillard reactions had different pyrolytic volatile properties and were suitable for the development of bakery food improver with different color and flavor requirements.