紫米色素的提取及稳定性研究

Extraction and Stability of Purple Rice Pigment

研究了提取剂、时间、温度、料液比及pH值对紫米色素提取液吸光值的影响,确定最优提取条件;另外,还研究了光照、氧化剂、还原剂及不同金属离子对紫米色素稳定性的影响。实验结果表明:pH值为2的70%乙醇提取剂、1∶20料液比(g/mL)、60℃、40 min为最优提取条件;紫米色素受光照、氧化剂及还原剂的影响显著(P<0.05),易发生褪色或变色;钠、钙、锌离子的添加对紫米色素的稳定性无显著影响(P>0.05),铁离子对其有增色作用,而铝离子则使其发生褪色。

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（P〈0.05）,which could make the pigment to fade or change color;sodium,calcium,zinc ions had no significant effects（P〈0.05） on the pigment stability;iron ions had hyperchromic effects,while aluminum ions would decrease the color of the pigment.