Evaluation of the antioxidant capacity of betalainic fruits and vegetables

Abstract

The present investigation determined total phenolics, ascorbic acid, betalain contents and the corresponding antioxidant capacities of betalain-bearing fruits and vegetables. In addition to differently coloured Swiss chard petioles (Beta vulgaris L. ssp. cicla [L.] Alef. cv. ‘Bright Lights’) and hypocotyls of white, yellow, and red beetroot varieties (Beta vulgaris L. ssp. vulgaris, cv. ‘Albina Vereduna’, cv. ‘Burpee’s Golden’, and cv. ‘Rote Kugel 2’), juices from cactus pears (Opuntia ficus-indica [L.] Mill. cv. ‘Gialla’ and cv. ‘Rossa’) and pitaya fruits (Hylocereus polyrhizus [Weber] Britton & Rose, H. undatus [Haworth] Britton & Rose, Selenicereus megalanthus [K. Schumann ex Vaupel] Moran) were included in this study. Antioxidant capacities were determined by application of the TEAC and FRAP assays, respectively, resulting in differing rankings of the commodities investigated. In both test systems, highest antioxidant capacity was shown for red beetroot extract while for the remaining samples no straightforward order could be established.