Effects of unsaturated C18 fatty acids on "glucose-glutathione" Maillard reaction: Comparison and formation pathways of initial stage and meaty flavor compounds

Abstract

To explore the effect of oleic acid, linoleic acid, and linolenic acid on "glucose-glutathione" Maillard reaction initial stage and meaty flavor compounds formation pathways, glutathione-Amadori compound was synthesized, and identified by Q/TOF and NMR. Depending on the concentration of glutathione and glutathione-Amadori compound quantified by UPLC-MS/MS, the unsaturated C18 fat acids inhibited glutathione Amadori compound formation or accelerated degradation, and oleic acid inhibited most markedly. The results showed that 65 volatile compounds were detected by GC-MS-O in four model systems. Particularly, following the addition of unsaturated C18 fatty acids, the content of meaty flavor compounds sequentially decreased from oleic acid to linoleic acid and then to linolenic acid. The CAMOLA (carbohydrate module labeling) demonstrated the 2-methylthiophene, 2-thiophenecarboxaldehyde, 4-mercaptophenol, 2-acetylthiazole, and thieno[3,2-b]thiophene formation pathways. Particularly, we found for the first time that the skeleton of 4-mercaptophenol generated from glucose. The volatile compounds of reaction systems were discriminated by heatmap and PCA analysis. These results highlights the effect of lipid composition on Maillard reaction and contributes to the control of savory flavor.

Keywords: Formation pathway; Glutathione-Amadori compound; Maillard reaction; Meaty flavor compounds; Unsaturated C18 fatty acids.