Designing of high voltage electric field for soybean and sunflower oil bleaching

• High voltage electric field (HVEF) could reduce %clay, temperature and time in oil industry with low energy consumptions;
• HVEF could be an alternative for bleaching method in the oil industry;
• HVEF could reduce pigments (carotenoids and chlorophylls) and polar compounds (PV, TBA and FFA) in refined oil;
• HVEF could produce micro and Nano clay by pulsed corona and pulsed spark type systems.

To the best of our knowledge, this work for the first time in the world carried out at the Tarbiat Modares University. In the present research, high voltage electric field (HVEF) method was utilized for bleaching of soybean and sunflower oil. For optimization of the bleaching process, the effect of different independent variables such as clay percentage (0.5–2%), voltage (0–24 kV), distance (8–12 mm), different numbers of cathode–anode (4–8) and inert-electrolyte (HCl; 0–50 mM) was studied. In order to compare the properties of the bleached samples using HVEF and control (industrial condition) bleaching methods, the indexes of Lovibond, Hunter lab, carotenoid, chlorophyll, bleaching efficiency (BE), peroxide (PV), tiobarbituric acid (TBA), free fatty acid (FFA), tocopherol, sterol and fatty acid composition were measured. According to the results, the BE value of HVEF technique in bleached soybean (88.35%) and sunflower oil (75.41%) were higher in comparison with the soybean (85.80%) and sunflower (58.14%) oils bleached using control method. Consequently, the HVEF bleaching method seems to be an alternative to the industrial method as it reduced clay percentage (50 and 66%), temperature (28% and 28%) and process time (35% and 35%) in soybean and sunflower oil bleaching, respectively.Industrial relevanceHigh voltage electric field (HVEF) method for bleaching of soybean and sunflower oil was done, for the first time in the world to the based of our knowledge, and was optimized under different conditions including clay percentage (0.5–2%), voltage (0–24 kV), distance (8–12 mm) with different numbers of cathode–anode (0–8), inert electrolyte (HCl; 0–50 mM). HVEF could be an alternative for bleaching method in the oil industry; HVEF could reduce %clay, temperature and time consumption in oil industry with low energy consumption; HVEF could produce micro and Nano clay by pulsed corona and pulsed spark type systems.-To Patent No: A23D; C11B; C11C; H03, “Design of high voltage electric field for the oil bleaching”, Tehran-Iran (2015).