有机酸对紫玉米芯色素的辅色作用

通过检测在紫玉米芯色素溶液中添加甘氨酸等几种有机酸后色素变化的动力学参数及其稳定性,探讨甘氨酸对紫玉米芯色素的辅色机理。结果表明:在pH5左右时甘氨酸辅色作用最明显,经过均匀实验条件优化,在色素质量浓度为0.96μg/mL、甘氨酸浓度为160mmol/L、Fe2+浓度为256mmol/L、温度75℃、pH值为5的条件下,10d后体系色素保存率为对照的1.49倍。甘氨酸对紫玉米芯色素的辅色机理主要是甘氨酸与花色苷发生了分子间相互作用,色素与甘氨酸以酯键结合后,活化能增加,从而提高了色素的稳定性。

Effect of Organic Acids on Storage Stability of Purple Corn Cob Pigment

The kinetic parameters of color change and the stability of purple corn cob pigment with the respective addition of several organic acids such as glycine were studied.The mechanism of the effect of glycine on the stability of purple corn cob pigment was also discussed.The results showed that glycine had the most pronounced effect on the stability of the pigment at pH 5.The results of uniform design optimization indicated that the retention rate of the pigment at 0.96 μ g/mL after 10 d of storage at pH 5 and 75℃ in the presence of 160 mmol/L glycine and 256 mmol/L Fe2+increased by 1.49-fold compared to the control without the addition of any organic acid.The possible mechanism may be mainly associated with the interaction between glycine and anthocyanins.It is speculated that glycine is bound to the pigment through ester bonds,resulting in an increased activation energy,thus enhancing the stability of the pigment.