薏苡仁油的提取方法、理化性质及脂肪酸结构分析

Analysis of extraction method,physicochemical properties and fatty acid composition of coix seed oil

通过比较采用5种提取方法所得的薏苡仁油品质,探讨提取薏苡仁油的最适宜方法,并研究该方法所得薏苡仁油的理化特性和脂肪酸的组成及位置分布。结果表明,超临界CO2萃取法可以提取得到品质相对较好的薏苡仁油,且得率可观;得到的薏苡仁油为淡黄色,澄清油状液体,具有其特有的清香,水分≤0.5%,相对密度为0.953~0.971,折光系数(n20)1.461~1.470,旋光度-2.6^+3.1。薏苡仁油中甘油三酯含量≥91.5%,其中至少含44.1%的油酸和28.2%的亚油酸;共鉴定出16种脂肪酸,不饱和脂肪酸的含量高达83.018%,且其几乎分布在sn-2位上,少量的饱和脂肪酸分布在sn-1、3位上,奇数碳链脂肪酸和长链脂肪酸C20~C24全都分布在sn-1、3位上。

The purpose of this research is to find a suitable method to extract CSO(Coix seed oil)with relatively better quality from coix seed and analyze physicochemical properties and fatty acids distribution in triglycerides of CSO.The results showed that supercritical CO2 extraction method was the optimum method as it could make relatively better quality and higher yield of CSO.CSO was a kind of liquid oil which had light yellow color and clarifying oil appearance.Moisture of CSO was less than 0.5%.Its relative density and refractive index were between 0.953~0.971 d254 and 1.461~1.470 n20,respectively.Optical rotation of CSO was between-2.6^+3.1.The content of triglyceride in CSO was more than 91.5%.The content of oleic acids and linoleic acids in fatty acid were more than 44.1%and 28.2%,respectively.16 kinds of fatty acid were identified in CSO and the percentage of unsaturated fatty acid in CSO was 83.018%.The percentage of unsaturated fatty acid located on sn-2 of triglycerides was 93.032%and a few percent of saturated fatty acid located on sn-1 or sn-3 of triglycerides.In this study,CSO was found to contain odd carbon chain fatty acids,which were rarely found in higher plants and animals.All of the odd carbon chain fatty acids and long chain fatty acids(C20~C24)were located on sn-1 or sn-3 of triglycerides.