Antioxidant activity of pansy flowers submitted to ionizing radiations

Abstract

Edible flowers are increasingly being used in culinary preparations, which require new approaches to improve their conservation and safety. Irradiation treatment might be the answer to these problems, ensuring food quality, increasing shelf-life and disinfestation of foods. Viola tricolor L. (johnny-jump-up) flowers are widely used in culinary preparations, being also acknowledged for their antioxidant properties and bioactive components. The purpose of this study was to evaluate the antioxidant activity of V. tricolor flowers submitted to electron beam and gamma irradiation at 0.5, 0.8 and 1.0 kGy, as also of non-irradiated samples (control). The antioxidant properties were evaluated through 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, reducing power and β-carotene bleaching inhibition assays. Total phenolics were also determined, using the Folin-Ciocalteu assay. The irradiated samples displayed a higher antioxidant activity, especially those treated with 1.0 kGy, independently of source, translated in a higher capacity to scavenge DPPH and to inhibit β-carotene bleaching. Accordingly, the applied irradiation treatments seemed to represent a feasible technology to preserve the quality of edible flower petals.