Effect of pH value and temperature on antioxidant activity of crude anthocyanins from Vaccinium vliginosum L.

In this study, anthocyanins were extracted from Daxing’anling wild Vaccinium vliginosum L. fruit. The antioxidant activities of crude anthocyanins from Vaccinium vliginosum L.were evaluated under different conditions by the abilities to scavenge ·OH, ABTS+, DPPH free radical and the total reduction capacity. The result indicated that the crude anthocyanins from Vaccinium vliginosum L. showed better antioxidant activity with the initial pH=1, then decreased with pHthe increase. DPPH radical scavenging activity was greatly improved under pH=5 and unable to be determined beyond pHexceeded 8.The activity of scavenging ·OH free radical reached a peak value in pH=5 and pH=10. ABTS+free radical scavenging activity obviously increased with the pH=8, 10. The total reduction capacity reached a maximum in pH=7, 9.The antioxidant activity of crude anthocyanins from Vaccinium vliginosum L. decreased with the increasing of temperature. However, it was found that the antioxidant activity of crude anthocyanins water bathed at 100℃ increased gradually with the increasing of pHafter the pHvalue exceeded 8. Finally, the antioxidant activity of crude anthocyanins water bathed at 100℃ were found to be more effective than water bathed at 60℃ and 80℃.