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Effect of enzymolysis-assisted electron beam irradiation on structural characteristics and antioxidant activity of rice protein

Li, Ting, Wang, Li, Sun, Dongling, Li, Yanan, Chen, Zhengxing
Journal of cereal science 2019 v.89 pp. 102789
2,2-diphenyl-1-picrylhydrazyl, amino acid composition, antioxidant activity, enzymatic hydrolysis, fluorescence, food industry, functional foods, graphs, hydrolysates, hydrophobicity, ingredients, irradiation, protein hydrolysates, rice protein
This research investigated the effect of enzymolysis-assisted electron beam irradiation (EBI) on the structural characteristics and antioxidant activity of rice protein (RP). The amino acid content of RP was increased by enzymatic hydrolysis, but the amino acid content of the rice protein hydrolysates (RPHs) was decreased gradually as the irradiation dose increased. Additionally, the secondary structural change of the irradiated hydrolysates revealed that a flexible and unfolded structure was induced by EBI. Irradiation increased the fluorescence intensity of the hydrolysates, which can probably be attributed to the exposure and changes in the surroundings of the hydrophobic region. Microscopic graphs showed that the tight conformation of the RP was destroyed by enzymolysis. Furthermore, the antioxidant activity of the RPHs was improved by EBI, with the highest 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity of 96.81% and 92.04% at 50 kGy, respectively. This study will provide a feasible coupling technology for the food industry to improve the antioxidant ability of RP. Consequently, irradiated hydrolysates could be regarded as a promising functional food ingredient due to their higher antioxidant ability.