Antioxidant activities of buckwheat extracts

The antioxidant activities of buckwheat (Fagopyrum esculentum Wench) extracts were evaluated and compared with butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tertiary butylhydroquinone (TBHQ) using a P-carotene bleaching assay, a 2,2-diphenyl-beta-picrylhydrazyl (DPPH) assay and the Rancimat method. Buckwheat was extracted with solvents of different polarities. The methanol extract showed the highest antioxidant activity coefficient (AAC) of 627 +/- 40.0 at 200 mg/l by the beta-carotene bleaching method and longest induction time of 7.0 +/- 0.2 h by the Rancimat method. The acetone extract showed the highest total phenolics of 3.4 +/- 0.1 g catechin equivalents/100 g and the highest scavenging activity of 78.6 +/- 6.2% at 0.1 mg/ml by the DPPH method. The properties of the extracting solvents significantly affected the yield, total phenolics and antioxidant activity of buckwheat extract. (C) 2004 Elsevier Ltd. All rights reserved.