Modification Of Porcine Pancreas Lipase By Tweens And Their Effects On Enzymatic Interesterification Of Oils And Fats

The effects of ratio of alcohol to water, adding amount of Tweens and stirring time onthe modification efficiency of PPLipase modified by Tweens in ethanol solution were studied.The effects of Tweens modified PPLipase on the enzymatic interesterification wasinvestigated. The influence of Tweens modified PPLipase on the selectively of P, St, and Owas discussed primarily.The optimum modified condition of the PPLipase by Tweens were as follows, Tween20:the ratio of alcohol to water1:2(v/v), adding amount of Tween205%, stirring time15min;Tween40: the ratio of alcohol to water1:2(v/v), adding amount of Tween4010%, stirringtime15min; Tween60: the ratio of alcohol to water1:2(v/v), adding amount of Tween605%,stirring time30min; Tween65: the ratio of alcohol to water1:2(v/v), adding amount ofTween655%, stirring time15min; Tween80: the ratio of alcohol to water1:3(v/v), addingamount of Tween805%, stirring time15min; Tween85:the ratio of alcohol to water1:3(v/v),adding amount of Tween855%, stirring time30min. And the thermal stability of PPLipasemodified by Tweens was enhanced in solvent system.The study of the effects of Tweens-PPLipase and PPLipase on the interesterification insolvent system, showed that the acyl incorporation of the reaction catalyzed by T60-PPLipase,T80-PPLipase and T85-PPLipase were higher than those of the PPLipase at40℃,50℃,70℃and60℃, and the acyl migration rate of Tweens modified PPLipase was lower than that ofthe PPLipase. The results of enzyme loading on the interesterification catalyzed byTweens-PPLipase indicated that in range of5%～15%, the acyl incorporation increased withenzyme dosage. The optimum enzyme dosage of T20-PPLipase, T40-PPLipase,T60-PPLipase, T65-PPLipase, T80-PPLipase and T85-PPLipase were15%. The results of theinfluence of Tweens-PPLipase and PPLipase on the selectivity of P, St, and O ininteresterification, showed that PPLipase modified by Tweens could not change the selectivityof fatty acids in the lipase catalyzed interesterification.