Hydrogen peroxide generation from hydrated protein drink mixes.
Generation of oxygen radicals upon hydration of powdered protein products was examined using luminol-enhanced chemiluminescence. Among individual proteins powders examined oxidative bursts occurred almost immediately, and then rapidly declined in the 1st 5 min. Commercially available powdered protein drink mixes behaved differently, with an initial lag phase followed by a sustained increase in luminol-enhanced luminescence, lasting for an hour or beyond. The drink mix that produced the highest level of luminol-enhanced luminescence also contained 379 nM ascorbate radical when hydrated (28 nmole/g of powdered drink mix). The entire ascorbic acid content of this drink mix was oxidized to nondetectable levels (using HPLC-diode array detection) within 60 min of being hydrated. Treatment of the hydrated drink mixes with the enzyme catalase almost completely inhibited the luminol-enhanced luminescence from the hydrated drink mix demonstrating that hydrogen peroxide generated via a chemical reaction among the drink mixes' ingredients was a primary reactive oxygen species (ROS). This is the strongest oxidative capacity demonstrated in a food product as consumed (without any manipulation to increase ROS) and the 1st time that the ascrobate radical in a food product as been quantified. Generation of hydrogen peroxide in the hydrated drink mixes from metal catalyzed reactions involving oxygen and reducing equivalents from ascorbic acid is proposed.
Dept. of Animal and Food Sciences, Univ. of Kentucky, 412 W.P. Garrigus Building, Lexington, KY, 40546-0215, U.S.A.
William L
WL
Boatright
D001628:Beverages / Q000032:analysis*; D002374:Catalase / Q000378:metabolism; D004044:Dietary Proteins / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000737:chemistry*; D049449:Luminescence; D008165:Luminol / Q000737:chemistry; D008894:Milk Proteins / Q000737:chemistry; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D030262:Soybean Proteins / Q000737:chemistry; D000067816:Whey Proteins
D004044:Dietary Proteins; D008894:Milk Proteins; D017382:Reactive Oxygen Species; D030262:Soybean Proteins; D000067816:Whey Proteins; D008165:Luminol; D006861:Hydrogen Peroxide; D002374:Catalase
ascorbate radical; hydrogen peroxide; luminol-enhanced chemiluminescence; oxygen radicals; soy proteins; whey proteins