甲醇溶液中酒石酸辅助尿素包合法富集α-亚麻酸

ENRICHMENT OF α-LINONEIC ACID BY TATARIC ACID-ASSISTED UREA FRACTIONATION IN METHANOL

以亚麻籽油为原料,采用酒石酸辅助尿素包合法富集其中的α-亚麻酸。研究了尿素/混合脂肪酸(mixed fatty acids,MFAs)、甲醇/MFAs、结晶温度和结晶时间对酒石酸辅助尿素包合法富集α-亚麻酸的影响;比较了甲醇体系中酒石酸辅助尿素包合法与传统尿素包合法富集α-亚麻酸产品中α-亚麻酸的纯度与回收率。研究发现,包合过程中的被包合顺序依次为:棕榈酸≈硬脂酸>油酸>>亚油酸>α-亚麻酸;酒石酸/尿素为1∶3(n/n)、尿素/MFAs为2.5∶1(m/m)、甲醇/MFAs为10∶1(V/m),结晶温度-8℃、结晶8 h时,富集产品中α-亚麻酸含量为78.6%,α-亚麻酸的回收率为60.9%。

Tartaric acid is a short carbon chain carboxylic acid with multi-hydroxyl group, which is easy to link with urea with hydrogen bond. It has been found that tartaric acid can assist the inclusion of fatty acids with urea in inclusion process, so as to improve the effect of inclusion. The present study was to investigate the enrichment of α-linolenic acid （α-LA） from linseed oil by tartaric acid-assisted urea fractionation. The effects of ratio of urea and mixed fatty acids （MFAs）, ratio of methanol and FAs, crystallization temperature and time on the enrichment of α-LA by the tartaric acid-assisted urea fractionation were studied. The purity and yield of α-LA in the enriched products obtained by the tartaric acid-assisted urea fractionation and traditional urea fractionation in methanol were compared. The results showed that the order of the fatty acids involved in the inclusion complex was palmitic acid ≈ stearic acid 〉 oleic acid 〉〉 linoleic acid 〉 α-LA. Under the optimum conditions of tartaric acid-to-urea ratio of 1：3 （n/n）, urea-to-MFAs ratio of 2.5 ： 1 （m/m）, methanol-to-MFAs ratio of 10：1 （ V/m ）, crystallization temperature of -8 ℃ and crystallization time of 8 h, the purity and yield of α-LA in the enriched product were 78.6% and 60.9%, respectively.