Polyphenols isolated from pomegranate juice (Punica granatum L.): Evaluation of physical-chemical properties by FTIR and quantification of total polyphenols and anthocyanins contente / Isolamento de polifenóis do suco da romã (Punica granatum L.): Avaliação das propriedades físico-química por FTIR e quantificação do teor total de polifenóis e antocianinas

Pomegranate (Punica granatum L.) is a polyphenols source, such as anthocyanins, punicalagin, ellagitannins and tannins. Polyphenols are antioxidant compounds present in foods as cereals, fruits (peels, seeds and juice), vegetables, wine, and among others. Polyphenols are responsible to protect cells and to limit the risks of degenerative and tumoral diseases, as well as, to prevent cardiovascular diseases, neuronal diseases, and present important anti-inflammatory effects. The purpose of this study was to isolate polyphenols from pomegranate juice using solvents without heating. The solvents used were ultrapure water, ethanol, ethanol 70% and methanol. The samples were characterized by FTIR to evaluate the physical-chemical properties, the total polyphenols content was quantified by Folin-Ciocalteau method, using gallic acid as standard equivalent, and the total anthocyanins content was quantified by pH-differential method, using anthocyanins (cyanidin-3-glucoside) as standard equivalent. FTIR spectra showed the main characteristic groups of polyphenols, as hydroxyl group and stretching vibration of benzene rings. And the characteristic groups of solvents were CH2 ou CH3, hydroxyl, carboxyl e carbonyl group. For the quantification of total polyphenols and anthocyanins content, the best results were found to the pomegranate juice: ultrapure water samples. According to the data obtained it was possible to conclude, who the process employed was effective to isolate the polyphenols from pomegranate juice and the use of different types of solvent influenced in the achievement of these results.