山杏种皮黑色素理化性质研究

Physicochemical Properties of Melanin from Prunus armeniaca var.ansu

山杏种皮黑色素具有黑色素典型的性质。稳定性研究表明:温度影响该黑色素的氧化还原状态,但对溶液的颜色无显著影响;pH<6时,冷冻使黑色素沉淀;光照使溶液褪色;随pH升高,溶液颜色略有加深;Na_2SO_3、Ca^(2+)、Cu^(2+)和Zn^(2+)有一定的增色护色作用,Al^(3+)、Mg^(2+)、Na^+、氨基酸、糖和淀粉对该黑色素无显著影响;有机酸使溶液略有褪色。本研究尝试以吸光度的对数对波长的回归直线斜率作为衡量黑色素稳定性的指标,该指标能够很好地反映出山杏种皮黑色素结构的改变。

The melanin from Prunusarmeniaca var. ansu exhibited typical physicochemical properties of melanin. The stability experiment showed that： Temperature affected the total phenolic content but did not change the color of the melanin solution. When frozen at pH 〈6 ,the pigment precipitated; ultraviolet and natural light had discoloration effect; with PH increased, it became more dark; Ca^2＋ , Cu^2＋ and Zn^2＋ had the function of color increase or color preservation. Mg^2＋ , Al^3＋ , Na^＋ , glucose, amino acid, sugar and starch did not affect the melanin, while pH, organic acid and reducer affected it slightly. Moreover, the slope of the log absorbance versus wavelength was employed as a parameter to evaluate melanin stability and the change of the slope could reflect the alteration in structure of the melanin.