Antioxidant activity and bioactive compound changes during fruit ripening of high-lycopene tomato cultivars

Abstract

Changes in bioactive compounds and antioxidant activities of an ordinary (Rio Grande) and three high-lycopene (HLY 13, HLY 18 and Lyco 2) tomato cultivars (cvs) were studied at four different fruit ripening stages (green, green-orange, orange-red and red-ripe). Lipophilic and hydrophilic antioxidant activities (LAA and HAA, respectively) were determined and their correlations with ascorbic acid (AsA), dehydroascorbic acid (DHA), total vitamin C (AsA+DHA), phenolics, flavonoids, total carotenoid and lycopene contents were investigated. The stage of ripening significantly influenced the total carotenoid and lycopene contents, as well as the LAA of all investigated tomato cvs. Good correlations between LAA and both total carotenoid and lycopene contents were found using either the TEAC assay or the FRAP assay. During ripening, cvs HLY 13 and HLY 18 exhibited more than 100% higher total carotenoid and lycopene contents compared to Rio Grande. At the red-ripe stage, cv HLY 18 accumulated the highest phenolic and flavonoid contents. However, Lyco 2 showed the highest levels of DHA and total vitamin C. Although, the HAA of studied tomato cvs were also significantly influenced by the ripening stages, HAA resulted correlated only to the levels of phenolics and flavonoids when the TEAC assay was used. However, using the FRAP assay, the HAA were well correlated to the total vitamin C and DHA contents.