Effect of gamma radiation processing on the antioxidant activity of ginger

Abstract

Biological activity of ginger, especially antioxidant activity, has been associated to their bioactive compounds, gingerols, mainly 6-gingerol. Foods have some key compounds, which regulate their taste, aroma and nutritional profile, even if they are present in low concentration. These compounds used to be sensitive to irradiation in high doses. The aim of this study was to evaluate the effectiveness of gamma irradiation from 60Co at doses 0, 5, 10, 15 and 20 kGy on ginger (ZINGIBER officinalle Roscoe), particularly about its antioxidant activity. The quantification of phenolic compounds was performed by Folin-Ciocalteu method and assessing the potential of antioxidant activity by the free radical [2,2 difenil-1-pricrilhidrazil (DPPH•)] scavenging and by Rancimat® method. The 6-gingerol quantification was performed by High Performance Liquid Chromatography (HPLC). There were no significant differences of total phenolic compounds in the irradiated samples compared to control (p>0,05). Eventhough, no irradiated extract showed higher ability on free radical scavenging. The Rancimat® method showed that antioxidant activity index (AAI) was not significant different (p>0,05) between analyzed extracts, as well as 6-gingerol quantification. It could be concluded that gamma radiation processing may be a feasible alternative for ginger because it does not significantly alter its major phenolic compounds or its significant antioxidant potential.