猪胰脂酶的非离子表面活性剂修饰对酶促酯交换过程的影响

EFFECT OF MODIFICATION OF PROCINE PANCREAS LIPASE BY NONIONIC SURFACTANT ON THE PROCESS OF ENZYMATIC INTERESTERIFICATION

用非离子表面活性剂（Tween40、Tween65、Span60、Span80、S1170和S1670）在乙醇溶液中修饰猪胰脂酶（procine pancreas lipase,PPLipase）,再用修饰的猪胰脂酶催化茶籽油和亚油酸进行酯交换.通过分析酯交换过程中酯交换量、酰基位移和产物中各组分含量的变化,研究非离子表面活性剂的修饰作用对酶促酯交换过程的影响.研究发现,修饰猪胰脂酶催化酯交换的活性都高于猪胰脂酶.反应达平衡前,各修饰酶所催化的反应酰基位移率都低于猪胰脂酶所催化的反应.反应平衡后,PPLipase催化酯交换的酰基位移最小,约为28%;S1670-PPLipase催化反应的酰基位移最高,约为41%;S1170-PPLipase、Tween40-PPLipase、Tween65-PPLipase、Span80-PPLipase和Span60-PPLipase催化反应的酰基位移在28%～41%之间.反应过程中随着酯交换量不断增加,甘三酯含量不断减少;甘二酯含量在反应开始的最初阶段迅速增加,而后基本维持不变;在反应开始的最初阶段未检测到甘一酯,反应接近平衡时含量快速增加.

The procine pancreas lipase （PPLipase） was modified by nonionic surfactants （Tween40, Tween65, Span60, Span80, Sl170 and S1670） in ethanol solution; and the modified PPLipases were used to catalyze the interesterification of camellia oil and linoleic acid. The interesterification rate, acyl migration and the composition content of the product were determined during the enzymatic interesterification to study the effect of the modification on the enzymatic interesterification process. The results showed that the interesterification activity of the modified PPLipases was higher than that of the PPLipase. Before the reaction equilibrium, the acyl migration rates of the interesterifcattion catalyzed by the modified PPLipases were lower than that of the interesterification catalyzed by PPLipase. After the reaction equilibrium, the interesterification catalyzed by PPLipase had the minimum acyl migration （about 28%）; the interesterification catalyzed by S1670-PPLipase had the highest acyl migration （about 41% ）; and the acyl migrations of the interesterification catalyzed by Sll70-PPLipase, Tween40-PPLipase, Tween65-PPLipase, Span80-PPLipase and Span60-PPLipase were between 28% and 41%. During the interesterification process, the interesterification rate increased, and triglyceride content decreased continuously; diglyceride content increased rapidly in the early stage and kept unchanged essentially;no monoglyceride was detected in the initial stage,but the monoglyceride contntent increased rapidly when the reaction tended to equilibrium.