Abstract: The gliadin-sugar system was established to simulate the glycosylation modification conditions. The effects of sugar species (monosaccharides, disaccharides and polysaccharides), natural antistatic (dextran) concentration, modification temperature and time, and natural inhibitors on the formation of methyl glyoxal (MGO), glyoxal (GO) and advanced glycation end products (AGEs) were determined by gas chromatography and fluorescence spectroscopy (λex/λem = 340 nm/465 nm). The emulsifying properties of the modified protein were evaluated. The results showed that the amount of various harmful products produced from monosaccharides was much higher than that from polysaccharides, especially a significantly increased amount of MGO compared with GO. Furthermore, the formation of three harmful products increased with increasing dextran concentration, temperature or time prior to reaching a plateau. Under alkaline and high temperature conditions, required for the gliadin-dextran modification system, the common natural inhibitors catechins, quercetin, rutin, genistein, ferulic acid, chlorogenic acid, emodin and capsaicin were unstable, making them less effective. The inhibitory effect of cysteine on MGO and AGEs was more than 70% while still improving the emulsifying properties of the modified protein.

Key words: wheat gliadin, glycosylation modification, 1,2-dicarbonyl compounds, advanced glycation end products, flavonoids