Phytochemical characterization, and evaluation of rheological and antioxidant properties of commercially available juices of berries

The consumption of berries and their contribution to improving the human health is a subject of considerable interest, have already resulted in several research projects and numerous clinical trials in humans. The main goal of this study was to evaluate the phytochemical composition (total reducing sugars, total phenolics, flavonoids, and anthocyanins) of some commercially-available juices of berries and associating it to their physicochemical (pH, density, and total solids), rheological and antioxidant properties. It was observed that in general, the juices analysed presented great concentrations of polyphenols and anthocyanins; and, in what concerns to their rheological properties, non-Newtonian pseudoplastic fluid characteristics (n < 1) were observed. The antioxidant properties of the juices were evaluated using both the DPPH free radical scavenging assay and the beta-carotene bleaching test. Overall, the results of the % Inhibition of DPPH free radical by the tested juices indicate that they possess considerable capacity to scavenge free radicals, resulting in good antioxidant properties. This study demonstrated that the physicochemical properties of the juices influence their rheological behavior; and the phytochemical composition impacts their antioxidant properties. Due to their antioxidant capacities, juices of berries could be considered functional foods.