芥子酸模拟体系化学氧化褐变反应

摘要

In order to determine the influence factor of sinapic acid chemical oxidation,so as to provide the basis for better control of fruits and vegetables browning,sinapic acid chemical oxidation simulation system was established.The sinapic acid concentration and browning degree were investigated at 315 nm and 420 nm by ultraviolet visible spectrophotometer.Chemical oxidation of sinapic acid accords with First order reaction kinetics model by kinetic fitting.The rate of chemical oxidation of sinapic acid was maximum at pH10.0 (5.38 h-1).The results of orthogonal test showed that the effect of temperature at 0.05 level on the chemical oxidative browning of sinapinic acid was significant and the effect of pH at 0.1 level on the chemical oxidative browning of sinapic acid was significant.The effect of concentration of sinapic acid at 0.1 level on the chemical oxidative browning of sinapic acid was not significant.Sinapic acid was more prone to chemical oxidation at piH10.0 than pH3.7 and pH7.0 and at 90 ℃ than 40 ℃ and 25 ℃.Sinapic acid is more susceptible to oxidative browning in high temperature and alkaline environment.For this feature,in order to as far as possible to avoid the occurrence of browning of fruits and vegetables,high temperature and alkali processing operations should be avoided.%为了明确芥子酸化学氧化的影响因素,为今后更好地控制果蔬及其制品的褐变提供理论依据,本实验以芥子酸建立模拟体系,采用紫外可见分光光度计法在315、420 nm处分别测定芥子酸浓度及氧化产物褐变度.结果表明,对芥子酸化学氧化进行反应动力学拟合,确定符合一级反应动力学模型,其中在pH10.0条件下反应速率最大(5.38 h-1).正交实验结果表明,温度在0.05水平对芥子酸化学氧化褐变度影响显著,pH在0.1水平对芥子酸化学氧化褐变度影响显著,浓度在0.1水平对芥子酸化学氧化褐变度影响不显著.芥子酸在90比40、25℃更容易发生化学氧化,在pH10.0比pH3.7、7.0条件更容易发生化学氧化.芥子酸在高温碱性环境下更易氧化褐变,针对这一特点,在果蔬的加工过程中为尽可能避免褐变的发生,应尽量避免高温高碱等加工操作.