Determination of antioxidant activity and antioxidant content in tomato varieties and evaluation of mutual interactions between antioxidants

Major antioxidants and antioxidant activity in eight varieties of tomatoes were determined. Hydrophilic and lipophilic antioxidant activity (HAA and LAA) was determined by the ABTS assay and ascorbic acid and carotenoid contents were determined by HPLC-DAD. The HAA has far more significant impact on total antioxidant activity (83%) as compared with LAA. HAA was increasing during all ripening stages and was strongly correlated with ascorbic acid content (r = 0.83). During the ripening the LAA was increasing till the III. stage of maturity and then decreased. The main carotenoids determined in the red-fruit tomatoes were lycopene, beta-carotene and lutein. The content of lycopene has been increasing equally during the ripening. beta-Carotene and lutein were intensively synthesized between the I. and II. stage of maturity. Among ascorbic acid, alpha-tocopherol, lycopene, beta-carotene and lutein standards ascorbic acid was determined as the most efficient antioxidant followed by alpha-tocopherol and beta-carotene. Antioxidant activity of ascorbic acid, alpha-tocopherol, beta-carotene and lutein grew equally with increasing concentration, however lycopene was the most effective in its lowest concentration. The analysis of two-component mixtures showed significant synergism between lycopene-lutein, lycopene-beta-carotene and alpha-tocopherol-beta-carotene. (C) 2011 Elsevier Ltd. All rights reserved.