Antioxidative capacity of tomato products

The antioxidative capacity of methanol/water and hexane extracts of five tomato juices, four canned tomatoes and four tomato pastes was measured using two test systems: with 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS(+)) and with linoleic acid emulsion. In both the ABTS assay and the linoleic acid system, most of the antioxidative capacity of analysed products was from the methanol-water fraction, which contained polyphenols and ascorbic acid. On the basis of the wet weight of the tomato products, tomato pastes had the highest activity towards ABTS(+) (micromoles of Trolox equivalents per gram) followed by tomato juices, and canned tomatoes. The inhibition of formation of thiobarbituric acid-reactive substances in the linoleic acid emulsion was strongly dependent on antioxidant concentration. The results suggest that tomato products, in addition to fresh tomatoes, may also be important in supplying dietary antioxidant, especially polyphenols and carotenoids.