Abstract
Crude rice bran oil (CRBO) contains high levels of oryzanol, a bioactive shows many significant benefits for human health. The content of oryzanol in CRBO is relatively low for recovery by solvent extraction. Tthe refinery by chemical process also causes to lose a significant amount of oryzanol. Dense membranes can be applied for treatment of CRBO to refine the oil. The limitation of dense membranes is high resistant to permeate flux, consequently, very low capacity. In this research, the porous composite membrane was applied for enrichment of oryzanol, simultaneously, refinery of CRBO. The influences of temperature, pressure and adding of organic solvent (ethanol and n-hexane) on the separation of oryzanol, phospholipids (PL) and wax were conducted. Results show that, increase in temperature led to increase in oryzanol rejection. On the other hand, increase in operating pressure and adding of organic solvent caused decrease in oryzanol rejection. Under the operating conditions as the following: polypropylene membrane (HR98PP), ambient temperature, 50 bar and adding n-hexane with 4: 1 (w:w) of solvent: CRBO, at 1.73 of the concentration factor; the content of oryzanol in accumulative permeate was 1.8 g/L, consequently, increased 1.41 fold compared to the feed. More than 97 % of PL and wax were rejected from the feed. It means that, treatment of RBO by composite membrane is the potential technique for not only enrichment of oryzanol, but also refinery of CRBO.
