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内容記述 |
The abilities of food products to cancel superoxide (O2•-) and the hydroxyl radical (•OH) and directly reduce stable nitroxyl radicals were assessed in the present study using electron paramagnetic resonance (EPR)-based methods. The antioxidant functions of vinegar samples, including one- and two-year-fermented black vinegar, were also examined.The abilities of the vinegar products to cancel O2•- were in the order of two-year-fermented black vinegar ≈ one-year-fermented black vinegar > standard vinegar. Standard vinegar, one-year-fermented black vinegar, and two-year-fermented black vinegar did not reduce the stable nitroxyl radical. Apple-flavored black vinegar, containing 300 mg/100 g of ascorbic acid, directly reduced the stable nitroxyl radical. The ability of two-year-fermented black vinegar to cancel •OH was slightly stronger than those of one-year-fermented and standard vinegars. •OH-canceling ability appeared to be due to the sugars and/or proteins present in sample vinegars, particularly apple-flavored black vinegar, which had a high carbohydrate content. The addition of vinegar to the reaction mixture enhanced the reduction of TEMPOL in the presence of GSH at a hyperthermal temperature in the order of apple-flavored black vinegar >> two-year-fermented black vinegar > one-year-fermented black vinegar > standard vinegar. The reduction of TEMPOL was attributed to the cancellation of H2O2, except for apple-flavored black vinegar, which directly reduced TEMPOL. Collectively, the present results suggest that fermentation increases the antioxidant ability of vinegar. The combination of EPR methods described herein is feasible for visualizing the antioxidant activities of food samples. |
