Avaliação da concentração por nanofiltração de suco de amora na composição e bioacessibilidade de antocianinas

Abstract

Blackberry is recognized for its high content of anthocyanins and other phenolic compounds with functional potential, although these compounds are sensitive to processing, storage, and digestion steps. This study aimed to evaluate the efficiency of nanofiltration in concentrating the bioactive compounds of blackberry juice, as well as to investigate the physicochemical stability of the concentrated product, the bioaccessibility of anthocyanins, and the effect of ascorbic acid addition. The juice was previously centrifuged and subjected to the nanofiltration process, and physicochemical parameters, total phenolic content, monomeric anthocyanins, antioxidant activity (ABTS and DPPH), and color parameters (CIELAB) were evaluated in the feed, permeate, and retentate fractions. The results demonstrated that nanofiltration showed high efficiency in concentrating the bioactive compounds of the juice, especially anthocyanins, with a concentration factor close to 2 for most analytes, confirming the performance of this process. The concentrated juice generally exhibited good physicochemical stability during frozen storage, preserving most of its bioactive compounds during the first 60 days, with more noticeable reductions only at the end of 90 days. In the simulated digestion, the presence of ascorbic acid did not promote additional degradation of anthocyanins and may have slightly favored their bioaccessibility. The observed degradation was mainly attributed to the alkaline pH of the intestinal phase and the intrinsic structural instability of anthocyanins. It is concluded that nanofiltration is a promising alternative for the development of functional blackberry-based beverages, with greater color intensity, higher bioactive compound content, and stability throughout storage.