绿豆色素的降解和颜色损失的研究

Chlorophyll degradation and color loss in mung bean

从绿豆中提取色素并对提取物进行鉴定,确定提取物中的一种主要绿色素为叶绿素a。研究了pH5.5、6.5、7.0,温度70、80、90、100℃下绿豆中色素的降解和颜色损失。通过色彩色差计测量,得出b、-a/b和L均符合一级反应动力学方程。在不同的温度和pH值下,b的活化能从7.83±1.44 kcal/mol提高到15.57±0.79 kcal/mol,-a/b的活化能从4.01±0.14 kcal/mol提高到17.27±1.38 kcal/mol。随着pH值降低,叶绿素降解和颜色损失加快,在pH7.0下叶绿素稳定性较高。

The compounds extracted from the mung bean were identified, of which the main green pigment was chlorophyll a. The chlorophyll degradation and visual color loss in mung bean were investigated at 70, 80, 90 and 100 ℃ of pH 5.5, 6.5, 7.0. The visual color degradation, as represented by the change of the b, the ratio–a/b, L value measured by tristimulous colorimeter, followed a first-order reaction. Activation energies for b values ranged from 7.83±1.44 kcal/mol to15.57±0.79 kcal/mol, and for–a/b values ranged from 4.01±0.14 kcal/mol to 17.27±1.38 kcal/mol with different temperature and pH values. Chlorophyll degradation and color loss accelerated with decreasing pH. Hence, chlorophyll was more stable at pH7.0.