Crossflow filtration of oils on metal oxides. Influence of chemical composition of the layer

A new technique of fat fractionation was described in which butter oil and a formulated oil (olive, grapestone, coconut, and linseed) have been submitted to crossflow percolation at 45 degrees C on different metal oxides layers (Al2O3, TiO2, ZrO2) of various thickness. The metal oxides layers were used in order to highlight the interaction between triglycerides (TG) and filtering materials. Experiments have been checked by high-performance liquid chromatography and by differential scanning calorimetry. Partition number was used to take the double bonds into account, and nonpolarity index was used to estimate the relative hydrophobicity of TG molecules. Results point out a two-step complex partition phenomenon: The filtering layer that is initially hydrophilic is coated by less hydrophobic TG acting as a second interface with hydrophobic characteristics. The three tested metal oxides did not provide comparable patterns. The specific property of aluminum oxide is related to a better polarizability of the Al-O bond.