Stability and Antioxidant Activity of Radish Red Pigment

Stability studies show that radish red pigment can remain stable under natural light and ultraviolet light.When it is below 80℃,pigment decomposed slowly.pigment decomposition accelerated significantly at 100℃.Loss rate reached 50% after 4hours' heating.Low pH is conducive to the stability of pigment and the capability of higher temperature.Metal ions are significant to the stability of pigment,among which Fe2+and Fe3+are conducive to the stability of pigment,but they are easy to produce complex precipitation with pigment;Zn2+,Cu2+,Al 3+decrease the pigment stability and promote the pigment decomposition;Mg2+has no effect on pigment.Antioxidant activity studies indicate that pigment has a good ability to scavenge free radicals.Half scavenging of superoxide anion,OH· and DPPHradical(IC50) are 0.31mg/mL,0.13mg/mL and 9μg/mL,the antioxidant capacity is slightly stronger than ascorbic acid.