TOWARDS AN EFFICIENT MEMBRANE-BASED VEGETABLE-OILS REFINING

The diversification of the non food uses of vegetable oils and the nee d for softer processing demands new oil refining processes. Taking adv antage of the membrane technology for vegetable oil refining, the prel iminary results reported here concern a single dead-end or crossflow m icrofiltration step. The influence of experimental parameters (tempera ture, pore size, pressure...) on the flow rate of permeate and on the free fatty acids (FFA) (as soap) and phosphorus retention ratios is di scussed. After addition of sodium hydroxide followed by dead-end filtr ation the quality of the oil meets the quality standard but the main d rawback is the very poor flow rate as a consequence of the rapid fouli ng of membranes. Cross-flow filtration allows a higher flow rate of pe rmeate which shows a slow decrease after operating for several hours, with only a slight loss of quality of the processed oil compared to de ad-end filtration. From this preliminary study, the cross-flow microfi ltration gives promising results for vegetable oils refining. This is the first report of simultaneous reduction of phosphorus, free fatty a cids and water concentrations after a solvent free single microfiltrat ion step. (C) 1998 Elsevier Science B.V.