Effect of Temperature on Color, Physicochemical Characteristics and Antioxidant Activities of Ovalbumin-Glucose System under Alkaline Condition

This study was conducted to investigate the effect of temperatures (4, 25 and 37 ℃) on the color, physicochemical characteristics and antioxidant activities of ovalbumin-glucose system during the Maillard reaction induced by alkali. The results showed that with increasing either incubation time or temperature, the color of ovalbumin-glucose system was deepened, and the contents of brown products and fluorescent compounds increased gradually; the content of intermediate products increased at 4 and 25 ℃, but increased at first and then decreased at 37 ℃ with increasing reaction time. Likewise, the pH increased at first then decreased. Fourier transform infrared (FTIR) spectroscopic analysis showed that ovalbumin was conjugated with glucose. Amino acid analysis suggested that the serine, histidine and cysteine residues in ovalbumin had relatively high reactivity, and the cysteine residue had the highest reactivity among them. The antioxidant activity of the reaction product from ovalbumin-glucose system was significantly improved compared with their physical mixture, but it slightly decreased with incubation time.