超声波辅助脂肪酶水解茶叶籽油条件的优化与动力学研究

Optimization and apparent kinetics research of tea seed oil hydrolysis catalyzed by lipase with ultrasound irradiation

研究无溶剂体系中超声波辅助脂肪酶水解茶叶籽油,通过单因素试验和正交试验获得最佳酶解条件为:油水比2∶3(g∶m L),加酶量为茶叶籽油质量的4.5%,缓冲液初始p H 8.5,超声波处理温度50℃,搅拌转速300 r/min,反应时间19.5 h。在此条件下,茶籽油的水解率达到72.25%。对其进行了表观动力学研究,测得超声波辅助脂肪酶水解茶叶籽油的米氏常数Km为0.053 m L/g,表观活化能Ea为14.05 k J/mol,比无超声波辅助酶解的Km=4.556 m L/g和Ea=30.73 k J/mol均降低,说明超声波能促进茶叶籽油的酶解。

Tea seed oil hydrolysis catalyzed by lipase under ultrasound irradiation was performed in solvent-free system. The optimized parameters were obtained by single factor and orthogonal test design as follows： oil-water ratio 2：3 （g： mL）, content of Lipase 4.5% （as oil wt）, initial pH of buffer 8.5, temperature of ultrasonic bath 50℃, mechanical agitation speed 300 r/min, reaction time 19.5 h. Under this condition, the hydrolysis rate was 72.25%. In addition, the apparent kinetic parameters Km and Ea of tea seed oil hydrolysis assisted by ultrasound were respectively measured as 0. 053 mL/g and 14.05 kJ/mol, which were less than those of controlled trial 4. 556 mL/g and 30.73 kJ/mol and suggested that ultrasonic bath could facilitate the hydrolysis of tea seed oil catalyzed by lipase.