Author: Herr Dr. Amoneit
Last saved by: Saritas, Sevim

The Role of Waxes in the Dry Fractionation of High Oleic-high Stearic Sunflower Oil 
Miguel A. Bootello, Rafael Garcés, Enrique Martínez-Force, Joaquín J. Salas
Instituto de la Grasa (CSIC), Sevilla, Spain

Waxes interfere with oil processing due to their high melting point and low solubility in the oil. They tend to crystallize and are responsible for the development of cloudiness when the oil is cooled to temperature below 20°C. Waxes are partially removed during refining of regular sunflower oil in the winterization or dewaxing process. High oleic-high stearic (HOHS) contains about four times more stearic acid than common sunflower oil. For that reason, the dewaxing of HOHS sunflower oil cannot be performed at low temperature in order to avoid losses of saturates in the wax cake. In the present work, we have studied the influence of waxes in the dry fractionation of HOHS sunflower oil at pilot plant scale. A high temperature partial dewaxing technique was applied to remove part of crystallizable waxes (those with 44 or more carbon atoms) without losing of saturated fatty acids. HOHS sunflower oils with different levels of waxes were dry-fractionated in a DeSmet mini-pilot plant equipped with a membrane filter. Fractionation of non-dewaxed oils was hampered by the clogging of the filtration cloths. On the other hand, partial dewaxing allowed fractionation of the oil in a range of temperatures from 19 to 17ºC. Clogging problems appeared again at lower temperatures, decreasing the filtration rates and limiting the range of temperatures at which this process was feasible.