乳木果油的超声波辅助提取工艺优化及脂肪酸组成分析

Optimization of ultrasound-assisted extraction process of Shea butter and its fatty acid composition

以乳木果核为原料对其所含油脂进行超声波辅助溶剂(正己烷)提取工艺优化及脂肪酸组成分析。在单因素试验的基础上,采用Plackett-Burman(PB)设计对影响乳木果油提取的5个因素(液料比、超声温度、超声时间、粒度、超声功率)进行筛选,根据PB试验优选结果,再以液料比和超声时间为考察因素,运用Central Composite响应面法对乳木果油的超声波辅助溶剂提取工艺进一步优化。结果表明:乳木果油的最佳提取工艺条件为液料比25. 7∶1、超声温度50℃、超声时间52min、粒度20目、超声功率320 W,在此条件下乳木果油得率为42. 36%。经分析测定乳木果油由8种脂肪酸(棕榈酸、棕榈一烯酸、硬脂酸、油酸、亚油酸、亚麻酸、花生酸、花生一烯酸)组成,其中以硬脂酸和油酸为主。乳木果油皂化值(KOH)为178 mg/g,不皂化物含量为11%。

The ultrasound - assisted solvent （ n - hexane） extraction of oil from Shea kernel was optimized and the fatty acid composition of Shea butter was analyzed. On the basis of single factor experiment, five factors （liquid to material ratio, ultrasonic temperature, ultrasonic time, particle size and ultrasonic pow- er） influencing Shea butter extraction were studied by Plackett -Burman （PB） test. According to the results of PB test, with liquid to material ratio and ultrasonic time as the investigation factors, the ultrasound -assisted solvent extraction process of Shea butter was further optimized by central composite re- sponse surface methodology. The results showed that the optimal extraction conditions of the Shea butter were obtained as follows ： liquid to material ratio 25.7 ： 1, ultrasonic temperature 50 ~C, ultrasonic time 52 min, particle size 20 meshes and ultrasonic power 320 W. Under the optimal conditions, the yield of Shea butter was 42.36%. The Shea butter consisted of eight kinds of fatty acids （ palmitoleic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, eicosenoic acid）, in which stearic acid and oleic acid were the main fatty acid. The saponification value and content of unsaponifiable matter were 178 mgKOH/g and 11%, respectively.