高油酸花生油酶促酯交换合成类可可脂工艺优化Optimization of synthesis of cocoa butter equivalent from high oleic acid peanut oil by enzymatic transesterificati

Abstract

为促进高油酸花生油的高值化利用，在无溶剂体系中以高油酸花生油为原料，棕榈酸乙酯、硬脂酸乙酯为酰基供体，酶促酯交换合成类可可脂。以目标甘三酯1,3-二棕榈酸-2-油酸（POP）、1-棕榈酸-2-油酸-3-硬脂酸（POS）、1,3-二硬脂酸-2-油酸（SOS）含量，硬脂酸指数和酰基位移率为评价指标，在单因素实验的基础上采用响应面法对酶促酯交换合成类可可脂的工艺条件进行优化。结果表明：酶促酯交换合成类可可脂的最佳工艺条件为硬脂酸乙酯与棕榈酸乙酯物质的量比1.3∶ 1、酰基供体与高油酸花生油物质的量比12∶ 1、加酶量2.7%(以底物质量计)、反应温度60 ℃、反应时间7 h，在该条件下产物甘三酯中POP、POS、SOS的含量分别为1455%、48.87%、25.17%，硬脂酸指数为0.56，酰基位移率为7.35%。产物的目标甘三酯组成和脂肪酸组成与可可脂相近，可作为可可脂替代品应用。In order to promote the high value utilization of high oleic acid peanut oil, cocoa butter equivalent was synthesized by enzymatic transesterification using high oleic acid peanut oil as raw material, ethyl palmitate and ethyl stearate as acyl donors in a solvent-free system. Taking the contents of target triglycerides POP,POS and SOS, stearic index and acyl migration rate as evaluation indexes, the process conditions of enzymatic synthesis of cocoa butter equivalent were optimized by response surface methodology on the basis of single factor experiment. The results showed that the optimal reaction conditions were obtained as follows: molar ratio of ethyl stearate to ethyl palmitate 1.3∶ 1, molar ratio of acyl donors to high oleic acid peanut oil 12∶ 1, enzyme loading amount 2.7%(based on the mass of substrate), reaction temperature 60 ℃ and reaction time 7 h. Under these conditions, the contents of POP, POS and SOS were 14.55%, 48.87% and 25.17% respectively, the stearic index was 0.56, and the acyl migration rate was 7.35%. The triglyceride and fatty acid composition of the product are similar to those of cocoa butter, and it can be applied as the cocoa butter equivalent.

Keywords

• 类可可脂；酶促酯交换；高油酸花生油；脂肪酸乙酯；酰基位移
• cocoa butter equivalent; enzymatic transesterification; high oleic acid peanut oil; fatty acid ethyl ester; acyl migration