Membrane separative techniques as candidates for alternative “green” processing of Oils and Fats present several advantages like energy saving, friendliness to environment and quality preservation of the final products. However, despite the considerable number of research programs carried out on several steps of the processing, including refining, desolvantisation and fractionation, no significant industrial development has been observed. Pointing out the lack of fundamental understanding of the mechanisms that rule the separations in hydrophobic media, a renewed approach of the membrane partition based on the relative hydrophobicity of lipids molecules vs barrier materials has been set up. Starting from an electronic analogy, a hydrophobic/hydrophilic valve has been designed by using a polar molecules coating on a porous material surface. The experimental realisation based on a two-compartments cell allowed to obtain preliminary results on the separation of the oily and water phases of an emulsion, that is a very promising result.