Evaluation of extracts from Gevuina avellana hulls as antioxidants

The antioxidant activity of the extracts from Gevuina avellana hulls was ev aluated and compared with that of BHT (butylated hydroxytoluene) and BHA (b utylated hydroxyanisole), using the beta-carotene bleaching assay, the acce lerated oxidation of crude soybean oil, and the 2,2-diphenyl-beta-picrylhyd razyl (DPPH) radical scavenging method. Solvents of different polarity were used to obtain the extracts. Both the extraction yield and the antioxidant activity were strongly dependent on the solvent. The ethanol and diethyl e ther soluble fractions were the most active with the beta-carotene assay. E thanol and methanol extracts were the most active in hydrogen radical scave nging activity. Water and methanol inhibited more efficiently the oxidation of soybean oil at 70 and 80 degrees C, respectively. As a general trend, i ncreased antioxidant activity was observed for increased extract concentrat ion. Except the acetone extracts, all were stable after 6 months storage at 4 degrees C. The ethanol solubles from G. avellana hulls present antioxida nt activity similar to that of synthetic antioxidants and to other reported residual agroindustrial materials.