紫薯花色苷的抗氧化活性及其稳定性研究

Study on Antioxidant Activity and Stability of Purple Potato Anthocyanin

本实验以紫薯为原料,以乙醇为浸提液提取其中花色苷成分并研究其抗氧化活性及其稳定性.结果表明:紫薯花色苷粗提物粉末中的花色苷含量为0.29mg/g,其在不同pH值下会有不同颜色变化.通过比较紫薯花色苷与Vc对DPPH、·OH自由基的IC50值,发现紫薯花色苷对DPPH、·OH自由基均有较好的清除能力.其IC50值分别为0.23、0.384mg/L均低于Vc的6.07、106.3mg/L,说明花色苷具有很强的抗氧化活性.另外,紫薯花色苷在不同温度、pH值、光照下均有很好的稳定性,最好的储存条件为4℃、pH4、避光.从红外光谱和电镜照片可以看出紫薯花色苷由于酰胺化而有了较好的稳定性,且其在多糖交联结构的保护下,增强了紫薯花色苷的稳定性.

In this experiment, anthocyanin was extracted from purple potato by using ethyl alcohol as solvent and its stability and antioxidant capacity were studied. The results demonstrated that the content of purple potato anthocyanin in crude extract power was 0. 29 mg/g which varied in color at different pH. According to the comparison of IC50 value between purple potato anthocyanin and Vc, it was found that purple potato anthocyanin has good ability to scavenging DPPH and ·OH radicals. The IC50 values of purple potato anthocyanin on DPPH and OH radicals were 0. 23 and 0. 384 mg/L, lower than those of Vc at 6. 07 and 106. 3 mg/L. Indicating the strong antioxidant activity. In addition, purple potato anthocyanin showed a good stability in different temperatures, pH and light level. And the best storage conditions were 4 ℃, pH 4 and darkness. The results of infrared spectroscopy and the scanning electron microscope shows that abundant amides existed in purple potato anthocyanin, which might be an important factor to its good stability. Moreover, the crosslinking structure caused by polysaccharide also enhanced the stability of purple potato anthocyanin.