蓝莓汁抗坏血酸体系非酶褐变反应动力学

Kinetics of Non-Enzymatic Browning Reaction from Ascorbic Acid Model System of Blueberry Juice

通过构建蓝莓汁抗坏血酸非酶褐变体系,测定蓝莓汁在贮藏(4、25℃和37℃)过程中的相关指标,并相应分别用零级、一级和复合动力学模型拟合。结果表明:褐变指数(A420 nm)符合复合动力学模型;贮藏过程中抗坏血酸不断降解,符合一级动力学模型;5-羟甲基糠醛含量的变化符合零级动力学模型。根据Arrhenius方程进行线性拟合,反映各指标随温度变化情况,在各贮藏温度下5-羟甲基糠醛的产生与褐变指数的变化呈现良好线性关系(R^2≥0.949)。

By building a non-enzymatic browning system containing ascorbic acid from blueberry juice, the relevant indicators of blueberry juice during storage（4, 25 and 37 ℃） were determined and tentatively fitted to zero-order, first-order and composite kinetic models. Browning index（BI; absorbance at 420 nm） complied with a composite kinetic model. The ascorbic acid was constantly degraded during storage, which could be described by a first-order kinetic model, while the 5-HMF content variation followed a composite kinetic model. Linear fitting was conducted using the Arrhenius equation to describe each indicator as a function of storage temperature. The generation of 5-HMF and BI showed good linear relationship（R^2 ≥ 0.949） at three different storage temperatures.