Pressurised solvent extraction of policosanol from wheat straw, germ and bran

Policosanols (PCs) are a group of long chain aliphatic alcohols that have been reported to have low-density lipoprotein (LDL) cholesterol-lowering properties. Wheat is a good source of these compounds. This study examined the effect of solvent type and temperature on extract yields and PC content and composition in the extracts. Wheat germ, straw and bran samples were extracted with petroleum ether, chloroform, n-hexane and ethanol at various temperatures ranging from 80 to 125 °C.Wheat germ extract yields were higher than those for straw and bran. Ethanol extraction resulted in the highest yield from wheat germ. Ethanol extract yields from both wheat germ and straw increased significantly with increasing temperature. Wheat straw had the highest PC content among the wheat fractions examined in the study. The PC composition of extracts varied with the type of solvent and wheat fraction used. Ethanol and petroleum ether extracts of wheat straw had the highest octacosanol and hexacosanol contents, respectively. This study demonstrated that solvent type and temperature have significant effects on extract yields and PC composition in extracts obtained from wheat fractions.