Extraction and Stability of Purple Rice Pigment

In this study,the pigment of purple rice was extracted.To determine the optimal extraction conditions,we studied the effects of extractant,time,temperature,solid-liquid ratio and the pH value on sample absorbance.In addition,the effects of light,temperature,oxidant,reducant and metal ion on the stability of purple rice pigment were studied.The results showed that the optimal extraction conditions were as follows: 70% ethanol extraction agent,1∶ 20 solid-liquid ratio(g/mL),60 ℃,40 min;the pigment stability was significantly affected by light,temperature,oxidant and reductant(P0.05),which could make the pigment to fade or change color;sodium,calcium,zinc ions had no significant effects(P0.05) on the pigment stability;iron ions had hyperchromic effects,while aluminum ions would decrease the color of the pigment.