Total and individual tocopherol contents of sunflower oil at different steps of refining

The contents of total and individual tocopherols of sunflower oils at different stages of industrial chemical and physical refining processes were determined by high-performance liquid chromatography (HPLC). According to the results, total and individual tocopherol contents gradually decreased until the end of the refining processes. The average losses of total tocopherol content during the chemical and physical refining processes were found to be 30.2% and 35.5%, respectively. The steam distillation stage of the physical refining process caused greatest overall reduction (average 24.6%) in total tocopherol content. In contrast to the physical refining process, the degumming-neutralizing stage in the chemical refining process caused greatest overall reduction (average 14.7%) in total tocopherol content. An additional average loss of 11.0% occurred during deodorizing in the chemical refining process. In both chemical and physical refining, the bleaching stage caused similar effects. The physical refining process caused higher loss in the total and individual tocopherol contents when compared with the chemical refining process. The conditions of the refining processes should be carefully evaluated to reduce the loss of tocopherols.