Phenolic composition and antioxidant capacity of aqueous and ethanolic extracts of blackberries/Composicao fenolica e atividade antioxidante dos extratos aquoso e etanolico de amora-preta

The objective of this study was to evaluate the content of phenolic compounds, anthocyanins and flavonoids extracted with 80% ethanol and water, and antioxidant capacity (DPPH and ABTS) of five blackberry cultivars produced in Western parana, Brazil. Brazos, Tupy, Arapaho, choctaw and Guarani blackberries were studied. Soluble solids, titratable acidity and ascorbic acid of fruits were also characterized. Total phenolic compounds ranged from 8.23 to 14.98 mg GAE [g.sup.-1] (f.w.) and Arapaho cultivar exhibited the highest contents in both solvents. Anthocyanins ranged from 2.57 to 9.42 mg Ecy3glu [g.sup.-1] (f.w.), being the solvent ethanol 80% more efficient than the water, and Choctaw cultivar showing the highest content. Flavonoids ranged from 0.46 to 1.14 mg EQ [g.sup.-1] (f.w.) and Guarani cultivar showed the highest content. High linear correlations were found between total phenolics and antioxidant capacity in both extraction solvents. However, linear correlations between anthocyanins and antioxidant capacity were observed only for the aqueous solvent. Ascorbic acid ranged from 87.87 to 134.09 mg 100 [g.sup.-1], with emphasis on Brazos cultivar. the aqueous extract showed greater ability to scavenge ABTS radical, but the ethanolic extract was more efficient for the DPPH radical. Blackberries produced under Western Parana conditions showed high levels of antioxidants with emphasis on Arapaho cultivar. This study showed that water and ethanol solvents influence different results on phenolic composition and antioxidant activity of blackberries. Index terms: Rubus spp., total phenolic, flavonoids, anthocyanins. O objetivo deste trabalho foi avaliar o teor de compostos fenolicos, antocianinas e flavonoides, extraidos com etanol a 80% e agua, e a capacidade antioxidante (DPPH e ABTS) de cinco cultivares de amora-preta produzidas na regiao oeste do Parana, Brasil. As amoras-pretas 'Brazos', 'Tupy', 'Arapaho', 'Choctaw' e 'Guarani' foram estudadas. Solidos soluveis, acidez titulavel e acido ascorbico tambem foram caracterizados. Compostos fenolicos totais variaram de 8,23 a 14,98 mg EAG [g.sup.-1] (p.f.) e 'Arapaho' exibiu os maiores conteudos em ambos os solventes. Antocianinas variaram de 2,57 a 9,42 mg ECy3glu [g.sup.-1] (p.f.), sendo etanol 80% o extrator mais eficiente, com o maior conteudo encontrado em 'Choctaw'. Flavonoides variaram de 0,46 a 1,14 EQ [g.sup.-1] (p.f.) e 'Guarani' mostrou o maior conteudo. Correlacoes lineares elevadas foram verifica