荸荠皮天然色素的纯化及其稳定性和抗氧化活性

Purification,stability and antioxidant activities of natural pigment from Chufa( Eleocharis tuberosa) peels

利用大孔树脂对粗色素进行了纯化,探讨了色素的纯化条件,并评价了色素的稳定性和抗氧化活性。结果发现:梯度洗脱大孔树脂,获得色阶高、黄酮含量高的荸荠皮色素,色价为379.1,黄酮含量为120.43 mg/g。所得色素的中性溶液有较好的热稳定性,在温度低于100℃时稳定;稳定性受溶液pH影响,在弱酸性、中性和弱碱性溶液中稳定,添加常用的中性、弱酸或弱碱性食品添加剂没有影响,在强酸或强碱溶液中颜色发生变化,直接添加强酸或强碱性添加剂对其有较大影响;色素的稳定性也受金属离子影响,常见的Na+、K+、Mg2+盐溶液对色素溶液没有影响,但含Al3+、Cu2+、Fe3+的溶液使色素颜色发生变化。该色素具有良好的还原能力和清除ABTS+·、DPPH·活性,清除自由基活性大于芦丁。

Fine natural pigment was extracted from Chufa peels. The pigment was purified by macroporous resin, and its stability and antioxidant activities were evaluated. The fine pigment with high color value was obtained using the D101 macroporous resin washed with gradient aqueous ethanol. The color value was 379. 1, and the total fla- vonoids content was 120.43 mg/g. The pigment was stable in neutral solution at temperature lower than 100 ℃. Its stability was affected by the pH. It was stable in the solution in weak acids, neutral solution and weak base. The neu- tral additives do not affect its stability. The pigment will change the color in strong acid or strong base as well as with strong acid or basic additives. The common salt of Na＋ , K＋ or Mg2＋ has no effect on the stability, however, A13＋ , Cu2＋ or Fe3＋ will change the color of the pigment. The purified pigment showed very strong reducing power and free radical scavenging activities against ABTS＋ , DPPH, and its scavenging capacities were stronger than those of rutin at the same concentration. The results suggested that the chufa peels pigment can be regarded as a natural antioxidants and has a great potential to explored as dietary edible pigment in future.