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The antioxidant properties of essential oils, spice extracts, ionol, ascorbyl palmitate, and their mixtures were evaluated according to the effectiveness of their inhibition of autoxidation of carotenoids in paprika extract. The degree of carotenoid oxidation was determined by spectrophotometry. The activities of coriander, and garlic essential oils, and red pepper extract were almost identical; oregano essential oil and rosemary extract had higher inhibitory activities, and the maximum activity was found in clove oil, ionol, and ascorbyl palmitate. The efficiency of the inhibition of carotenoid autoxidation decreased by 4–10% with a decrease in the concentration of all antioxidants from 4 to 1% by the carotenoid weight. Rosemary extract inhibited autoxidation in proportion to the concentration, while the degree of inhibition was 67% at a content of 4% and 29% at 2%. The composition was found to have a complex effect on the effectiveness of inhibition for antioxidant mixtures. Therefore, in mixtures containing clove essential oil, the total activity remained close to the activity of this essential oil. Rosemary extract reduced the activity of clove oil in a 1 : 1 mixture by 18% but did not affect the activity of oregano essential oil, ascorbyl palmitate, or ionol. No pronounced additive or synergistic effects were observed in any antioxidant mixtures. [ABSTRACT FROM AUTHOR]

Abstract: A method for the estimation of antioxidant properties of natural and synthetic preparations was developed based on inhibition of the autoxidation of paprika carotenoids. Carotenoids in the form of paprika extract were coated on a porous inert polysaccharide. Autoxidation of paprika carotenoids occurs more rapidly in such system than with direct methods for the determination of antioxidant inhibitory properties. It was shown that the developed method had good reproducibility. The behavior of paprika carotenoids, which was studied in systems with various types of starches, showed that the developed method could be used to evaluate the protective properties of food biopolymers in relation to lipid autoxidation. Moreover, the method is effective for comparison of the activity of both synthetic and natural antioxidants. The most important advantage of the method is that paprika carotenoids are almost identical to unsaturated fatty acids in their ability to interact with oxygen radicals of oxidants. Therefore, the results reflect the behavior of antioxidants in both real lipid-containing model systems and food products. [ABSTRACT FROM AUTHOR]