番茄红素在大豆油中的热异构化动力学

Isomerization Kinetics of Lycopene in Soybean Oil During Heating

番茄红素的降解和异构化对其生理功能和营养价值有很大影响,在受热情况下,番茄红素很易发生从全反式向部分顺式异构体的转化。通过对番茄红素在大豆油中受热引起的异构化动力学进行实验研究,为开发含番茄红素的功能食用油产品提供了一定指导作用。实验采用紫外-可见吸收光谱法,测定了番茄红素在大豆油中恒温处理不同时刻的浓度变化,结果表明,溶解在大豆油中的番茄红素在热处理初期,主要发生全反式异构体向部分顺式异构体的转变,然后才是番茄红素的降解破坏。在70、80、90℃下,番茄红素在大豆油中的异构化属一级反应动力学模型,且速率常数分别为1.74×10-3、4.96×10-3和1.02×10-2min-1,异构化表观活化能为93.1kJ/mol。

The thermal degradation and isomerization of lycopene are related to its potential health benefits and nutritive value. Lycopene isomerization easily happens during heating process. The isomerization kinetics of lycopene in soybean oil during heating was investigated by detecting the concentration change in the heating process. All-trans lycopene was heated in soybean oil at 70, 80 and 90?℃,respectively. The concentrations of lycopene were determined by means of UV/Vis. spectrometry. The isomerization (from all-trans isomer to cis-isomers) is a dominating reaction in the initial period and then the degradation takes place in the last period.The isomerization of lycopene follows a first-order kinetic model and the isomerization rate constants are 1.74×10^(-3), 4.96×10^(-3) and 1.02×10^(-2)min^(-1) at 70, 80 and 90?℃ respectively . The apparent activation energy is 93.1?kJ/mol.