Content of tocopherol-antioxidant in grape-seed oils obtained by methods of pressing and extraction
In the research work method of microcalorimetry was used to determine the content of tocopherol-antioxidant in grape-seed oils produced using various technologies. The method is based on the registration of the heat of the model reaction of cumene oxidation in the presence of grape-seed oils. The fatty acid composition and physicochemical characteristics of the extraction oil and those of oils obtained by pressing were paralleled. Compared to the method of pressing, the extraction with chlorofluorinated hydrocarbons (freon) made it possible to obtain grape-seed oil with a plenty of non-oleaginous impurities, reflected in the increase of antioxidants content from 2,1.10-3 mol/kg for pressed oil to 2,5.10-3 mol/kg for extraction oil. The content of vitamin E for the studied oils ranged from 53 to 109 mg %. It was shown that the refining and deodorizing of grape-seed oil reduced the content of tocopherols by half.