Extraction and Determination of Protein from Edible Oil Using Aqueous Biphasic Systems of Ionic Liquids and Salts

This study aimed to develop the extraction method of protein from edible oil for rapid detection. Firstly, aqueous biphasic systems (ABS) based on six hydrophilic ionic liquids (ILs) and three salts were developed and the phase diagram was drawn by turbidimetric point method. The binodal curves were fitted to the Merchuk equation. On this basis, the ABS composed of IL and salt were applied to extract protein from edible oil. The type of IL or salt, IL concentration, salt concentration, oil mass, extraction pH, and temperature on the extraction efficiency of protein from oil were investigated. The results showed that the optimum conditions for the extraction of protein from edible oil with ABS were as follows: 50% (w/v) K 3 PO 4 , 20% (w/v) [Bmim]Cl at 35 ℃, and pH 9.0. Under the optimal conditions, the protein extraction efficiency was almost 100%. Also, the extraction mechanism was studied and the main driving factors of protein extraction may be the hydrophobicity, electrostatic interaction, and salting-out between molecules. Finally, the method was used to detect the commercial edible oils from different sources. The results showed that the ABS could also be used to extract protein from other edible oils. In conclusion, the IL-based ABS method is simple and rapid for protein extraction from edible oil, and will highlight novel possibilities in the large-scale separation and purification of protein from oily solution.