Antioxidants are substances, that prevent oxidization of other molecules. They can be found in various foods most commonly in vegetables and fruits. They are often added to food as food additives. The most important antioxidants in plant oils are various analogs of vitamin E, tocopherols and tocotrienols. Some unrefined plant oils also contain some other, more polar antioxidants, such as sesamol, pinoresinol, tyrosol and hydroxytyrosol and their derivates, that are extracted along with vitamin E into the oils. The aim of this master thesis was to determine the antioxidative potencial of different plant oils in polar and non-polar fraction with DPPH in various solvents. DPPH method is one of the most frequent methods for evaluation of antioxidant potential (AOP) of oils. AOP was analyzed in ethylacetate and in the mixture of alcohols containing acid base pair. We found out, that the contribution of polar fraction to the AOP was greater in olive and sesame oil than in linseed and sunflower oil. Our data also show, that the sum of AOP for polar and non-polar fraction is the same as the AOP of unfractionated oil. DPPH assay performed in the mixture of alcohols containing acid base pair can be applied for rapid estimation of tocopherol content in sunflower and linseed oils.
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