Towards an efficient membrane based vegetable oils refining

The diversification of the non food uses of vegetable oils and the need for softer processing demands new oil refining processes. Taking advantage of the membrane technology for vegetable oil refining, the preliminary results reported here concern a single dead-end or crossflow microfiltration step. The influence of experimental parameters (temperature, pore size, pressure...) on the flow rate of permeate and on the free fatty acids (FFA) (as soap) and phosphorus retention ratios is discussed. After addition of sodium hydroxide followed by dead-end filtration the quality of the oil meets the quality standard but the main drawback is the very poor flow rate as a consequence of the rapid fouling of membranes. Cross-flow filtration allows a higher flow rate of permeate which shows a slow decrease after operating for several hours, with only a slight loss of quality of the processed oil compared to dead-end filtration. From this preliminary study, the cross-flow microfiltration gives promising results for vegetable oils refining. This is the first report of simultaneous reduction of phosphorus, free fatty acids and water concentrations after a solvent free single microfiltration step. (C) 1998 Elsevier Science B.V.