花青素类天然色素的光降解比较

目的 从天然产物中提取黑米、苋菜红、葡萄红这三种花青素类色素，并比较它们的光稳定性。方法 在统一的环境条件下，使用相同的辐射光源、照度，在近似相同的初始吸光度值下，对这三种色素的光稳定性进行比较研究。结果 花青素类天然色素在白炽灯下较为稳定，而在高压汞灯照射下，光降解速度明显加快。随着照度的增大，花青素类色素的光降解速率也增大，但光降解速率常数的改变和照度之间不存在线性对应关系。结论 黑米天然色素的光稳定性优于苋菜红和葡萄红天然色素。

Comparison of Photic Decompositions among Natural Anthocyan Pigments

Objective To study and compare photic stabilities among extracted black rice, amaranth and grape pigment from natural products. Methods To study the photic stabilities of these three types of pigment in an uniform environmental condition, using the same radiation lamp-house with the same illuminance. Results The natural anthocyan pigments were relatively stable under the radiation of incandescent lamp, whereas their photic decomposition rates became faster under the radiation of high-pressured mercury lamp. When the illuminance rose, the photic decomposition rates of the natural anthocyan pigments rose as well, but there was no linear relation between photic decomposition rate and illuminance. Conclusion The black rice pigment is more stable than amaranth and grade pigments.