Membrane processing of crude palm oil

The performance of a nonporous composite polymeric membrane was evaluated for processing crude palm oil and palm olein under both undiluted and hexane-diluted conditions focusing on the refining aspects besides retention of nutrients. The phospholipid contents of crude palm oil and palm olein were low and probably very close to the critical micelle concentration necessitating the use of a nonporous membrane for its effective removal. Membrane showed very high selectivity between triglycerides and phospholipids even under hexane-diluted conditions and the phospholipid rejection was nearly complete (95–100%). The membrane did not exhibit any appreciable selectivity towards carotenes and antioxidants (tocopherols and tocotrienols) that enabled their retention in the processed oil. Fatty acid composition of palm oil, which differs from other crude vegetable oils, seems to play some role in the permeation of tocopherols along with triglycerides. Oil flux improvement by one order of magnitude at a very low dilution with hexane (1:1) without affecting the membrane performance is an attractive feature, offering greater productivity.