红凤菜红色素水溶液的稳定性试验

从红凤菜（Gynura bicolor DC.）地上部分提取了红色素水溶液。在350－700nm范围内的扫描结果显示，该色素有2个吸收峰，位于543nm和598nm附近。在pH2.2-6.0的范围内色素较稳定。加热使其吸收峰值增大，但波长基本不变。0.2mmol/L Fe^3 引起色素溶液变色并产生大量沉淀；Al^3 也能使其产生沉淀；Cu^2 对该色素的影响较小；Zn^2 、对其无影响。氧化剂（H2O2）与还原剂（Na2SO3）均能使该色素褪色。光照对该色素无明显影响。

Detecting the stability of the red pigment aqueous solution from Gynura bicolor DC

The red pigment has been extracted from the above-ground part of Gynura bicolor DC. In range of wavelengths 350-700 nm, this pigment has two absorption peaks with the wavelength of 543 nm and 587 nm. The pigment is stable in the range of pH 2.2-6.0. Heating increases the value of absorption peak, but the wavelengths change little. Fe+{3+} (0.2 mmol/L) can alter its color and bring a great deal of precipitation; Al+{3+} can also bring precipitation; the influence of Cu+{2+} is small and Zn+{2+} is not notable. Both oxidant(H-{2}O-{2}) and reductant(Na-{2}SO-{3})can discolor the pigment which has no obvious reaction to illumination.