Improving solvent-free extraction of policosanol from rice bran by high-intensity ultrasound treatment

Rice bran, a rich source of nutrients and pharmacologically active compounds, is currently discarded or used as livestock feed, only small amounts being earmarked for oil production. Oil extraction can be efficiently performed in 30 min under high-intensity ultrasound either with hexane or without any organic solvent, using a basic aqueous solution instead. Under sonochemical conditions bran wax can also be hydrolyzed yielding policosanol (common name for a mixture of C-24-C-34 linear saturated fatty alcohols). We suggest that wax, a waste of rice oil manufacture, should be exploited to recover its alcoholic moiety that is very rich in policosanol. Quantitative data on extraction and purification of policosanol are presented. Both the first bran fraction from rice polishing and the discarded wax from the manufacture of rice oil are convenient and profitable starting materials for the production of policosanol.