Potencial antioxidante de extratos da casca de romã (Punica granatum L.).

Abstract

Pomegranate (Punica Granatum L.) has attracted the interest of science for its functional and therapeutic properties, including its antioxidant, anti-inflammatory and antimicrobial potential. Thus, the objective was to evaluate the antioxidant potential in lyophilized extracts of pomegranate peel, determining the antioxidant and anticholinesterase activities and the quantification of bioactive compounds. In addition, study the drying kinetics of pomegranate shells and evaluate the effect of convective drying at different temperatures on the physical and chemical properties of the flours obtained. The pomegranate shells were cut into slices with 5.0 x 1.5 x 0.4 cm and dried in an oven with forced air circulation adjusted at temperatures of 50, 60 and 70 ºC. Several mathematical models and a diffusion model were used to describe the drying kinetics. After drying, the shells were crushed to obtain flours and characterized for physical and physicochemical characteristics. The experiment was installed in a completely randomized design, with three replications, and the data were submitted to analysis of variance by the F test and the Tukey test at 5% probability level. According to the results, it was found that the Page model presented the best fit to the experimental data. The increase in drying temperature increased the effective difusivity and its relationship with temperature can be described by the Arrherius equation. The flour obtained at 70 ºC showed lower moisture content and higher percentages of total soluble solids, acidity, total carbohydrate, proteins, lipids, ash and minerals. The flours obtained presented good solubility, fluidity and acceptable flow capacity and high densities. The flour obtained after drying at 50 °C was selected to obtain the 70% hydroalcoholic extract. The extract obtained was concentrated, added from the drying adjuvant maltodextrin at different concentrations (35, 40 and 45%) and lyophilized to obtain the dry extract. The lyophilized extracts were characterized for physical and physicochemical parameters, total phenolic compounds, total tannins, flavonoids, anthocyanins and total carotenoids, in vitro antioxidant activity by ABTS and DPPH methods and inhibition activity of acetylcholinesterase enzyme. The lyophilized extracts have high percentages of bioactive compounds, especially total phenolics and tannins. The antioxidant activity was expressively high by the ABTS and DPPH assays. The extracts revealed important anticolinesteric activity. The extract ELM35 stood out for the higher values of bioactives, high antioxidant capacity and inhibition power of the enzyme acetylcholinesterase. It can be stated that the pomegranate peel represents a potential source of compounds with antioxidant properties and is a viable alternative for application in several products.