| 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 power) 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 response 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?℃, 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. |
