Total phenolics and antioxidant capacity "in vitro" of tropical fruit pulps/Fenolicos totais e capacidade antioxidante in vitro de polpas de frutos tropicais

The consumption of fruit, pulps has been highly recommended for its nutritional value, high-fiber, vitamin C and carotenoids. Recent studies have demonstrated these foods as sources of phenolic compounds with antioxidant activity, therefore, free radical scavengers, with a protective effect against the emergence and development or degenerative processes that lead to chronic diseases. Due to the increasing commercialization and consumption of fruit pulp in Brazil, especially in the city of Teresina, Piaui, this study selected a group of fruit pulp of high local consumption to evaluate the total phenolic content and antioxidant activity in vitro by the method of capture of free radicals: DPPH (1,1-radical diphenil-2-picrilhydrazil) and ABTS (2,2 'azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)). The fruit were selected Acerola (Malpighia emarginata DC.) Bacuri (Platonia insignis Mart.) Caja (Spondias mombin L.), Cashew (Anacardium occidentale), Guava (Psidium guajava) and Tamarind (Tamarindus indica L.). The levels of phenolics found in the frozen pulp of fruit exhibited relevant quantities of polyphenols, especially if the pulp with 835.25 ± 32.44 and 449.63 ± 10.24 mg/100g in hydroalcoholic and aqueous extracts, respectively followed by cashew pulp with 201.61 ± 19.15 and 165.07 ± 4.10 mg/100g. The pulp of tamarind bacuri showed the lowest levels of total phenolics. Regarding the antioxidant activity in vitro, the best results were found for aqueous and ethanolic of pulp of acerola, cashew and guava. The antioxidant activity of these pulps (E[C.sub.50] in mg/mL) ranged from 24.42 to 413.36 and 1.74 to 259.18 for the hydroalcoholic and aqueous extracts, respectively. Using the ABTS radical, the antioxidant activity for these same fruit pulps showed that TEAC values ranged from 3.69 ± 0.209 to 0.052 ± 0.013 (mM Trolox/g of pulp). We observed that a direct correlation exists between the amount of total phenolics and antioxidant activity in the analyzed pulps. Index Terms: antioxidant activity, ABTS, DPPH and fruit. O consumo de frutos e suas polpas tem sido muito recomendado por seu valor nutricional, alto teor de fibras, vitamina C e carotenoides. Trabalhos recentes tem apontado esses alimentos como fontes de compostos fenolicos com acao antioxidante, portanto sequestradores de radicais livres, com acao protetora contra o surgimento e/ou desenvolvimento de processos degenerativos que conduzem a doencas cronicas nao transmissiveis. Devido a crescente comerci