Assessment of Antioxidant Functions of Food Using Electron Paramagnetic Resonance Spectrometry: Verification Using...

Area of Science:

• Food Science
• Biochemistry
• Analytical Chemistry

Background:

• Oxidative stress is implicated in various health issues.
• Antioxidants play a crucial role in mitigating oxidative damage.
• Vinegar, a fermented food product, is explored for its potential antioxidant properties.

Purpose of the Study:

• To evaluate the antioxidant activities of different vinegar samples.
• To assess the capacity of vinegar to quench superoxide (O₂ ^•-) and hydroxyl radicals (^•OH).
• To determine the direct reduction of stable nitroxyl radicals by vinegar.

Main Methods:

• Electron paramagnetic resonance (EPR)-based assays were employed.
• Superoxide radical scavenging activity was measured.
• Hydroxyl radical quenching ability was assessed.
• Direct reduction of stable nitroxyl radicals was evaluated.

Main Results:

• Vinegar's ability to quench superoxide radicals increased with fermentation duration (2-year > 1-year > standard).
• Apple-flavored black vinegar demonstrated direct reduction of nitroxyl radicals due to ascorbic acid.
• Hydroxyl radical quenching was slightly enhanced in longer-fermented vinegars, linked to sugars/proteins.
• Vinegar addition enhanced TEMPOL reduction at hyperthermal temperatures, primarily via H₂O₂ quenching.

Conclusions:

• Fermentation significantly enhances the antioxidant potential of vinegar.
• Specific components like ascorbic acid contribute to direct radical reduction.
• EPR methods provide a viable approach for assessing food antioxidant activities.