title: Characteristics and enhanced antioxidant activity of egg white protein selenized by dry-heating in the presence of selenite.
abstract: This study reports a new method for the selenization of food proteins. Egg white protein (EWP) was selenized by dry-heating in the presence of selenite, and the physiochemical and functional properties of the selenized EWP were investigated. Selenization was accelerated with a decrease in pH from 7.0 to 3.0, an increase in heating time from 1 to 5 days, and an increase in incubation temperatures from 25 to 80 °C. The electrophoretic mobility of EWP increased with an increase in the level of selenization. Heat-induced polymerization of EWP was promoted by dry-heating in the presence of selenite. The selenite group was acid-stable and base-labile, which suggests that it was bound to the hydroxyl group of an amino acid and formed an -O-SeHO2 linkage. (77)Se NMR spectral data also suggested that the selenite bond (-O-SeHO2) was bound to EWP. The digestibility of EWP was improved by selenization. The antioxidant activities of EWP, including ABTS(+) free radical scavenging capacity, hydroxyl radical scavenging capacity, reducing power, and the Fe(2+) chelating capacity, were remarkably enhanced by selenization. This finding is the first to describe that EWP can be selenized by dry-heating in the presence of selenite and that the antioxidant activities of EWP are markedly enhanced by selenization. This points to a potentially new method for generating antioxidant food protein and a new method for preparing organic Se.
authors: School of Chemical Science and Technology, Yunnan University , Kunming 650091, People's Republic of China.
authors: Jinping
authors: J
authors: Zhao
authors: Hui
authors: H
authors: Zhao
authors: Xiaoyan
authors: X
authors: Wang
authors: Rong
authors: R
authors: Huang
authors: Hirofumi
authors: H
authors: Enomoto
authors: Zhikun
authors: Z
authors: He
authors: Can-Peng
authors: CP
authors: Li
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D055598:Chemical Phenomena; D004527:Egg Proteins / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry; D007502:Iron Chelating Agents / Q000737:chemistry; D010084:Oxidation-Reduction; D020887:Selenious Acid / Q000737:chemistry*; D012643:Selenium / Q000032:analysis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D004527:Egg Proteins; D005296:Ferrous Compounds; D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D017665:Hydroxyl Radical; D020887:Selenious Acid; D012643:Selenium