Stability of Red Pigments of Peristrophe roxburghiana

[Objective] The stability of Peristrophe roxburghiana red pigments were discussed.[Method]Taking ethanol as solvent,the red pigments were extracted from P.roxburghiana by using ultrasonic assisted extraction method,the stability of the pigments at various pH,temperature,light,oxidants,reducing agents,food additives and various metal ions conditions were detected.[Result] The pigments were soluble easily in water and ethanol;medium orange-red emerged in less than 11 of pH value,more stably in performance;yellow green appeared when the pH value was greater than 12,performance of red pigments was instability;the pigments were stable to heat and light;oxidant make pigments color fading;food additive sucrose,such as citric acid,potassium sorbate had little influence on the pigments,adn ascorbic acid make pigment color fading;K+,Na+,Cu2+,Mg2+,Zn2+,Ca2+on the pigments had no negative effects,while added Fe3+,Al3+,the phenomenon appeared dim reddish,Fe3+,Al3+ had a certain impact on the stability of pigments.[Conclusion] P.roxburghiana red pigment were a kind of stable drug-edible material which can be worthy of further research and utilization.