Effect of gamma radiation processing on turmeric: Antioxidant activity and curcumin content

The aim of this study was to evaluate the effectiveness of gamma radiation from 60Co at doses 0, 5, 10, 15 and 20 kGy on turmeric (Curcuma longa Linn.). 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-pricril-hidrazil (DPPH
- )] scavenging and by Rancimat® method. The curcumin quantification was performed by High Performance Liquid Chromatography. Compared to control, there were significant losses (p < 0,05) of total phenolic compounds in the samples irradiated with 15 kGy (p = 0001) and 20 kGy (p = 0001). Regardless the irradiation, there was no decrease in the ability to scavenge free radicals. The Antioxidant Activity Index (Rancimat® method) was significantly lower (p < 0,05) in 5 kGy (p < 0001) and 15 kGy (p = 0003) irradiated extracts and the curcumin quantification was significantly lower (p < 0,05) in 15 kGy irradiated extract (p < 0001). It is concluded that gamma radiation processing technology on turmeric can be viable. To maintain safety of antioxidant activity it should be applied doses up 10 kGy.