摘要：Background. Berry juices are a rich source of phenolic compounds exhibiting antioxidant activity. Unfortunately, polyphenols and especially anthocyanins are degraded during storage. Materials and methods. The levels of total phenolic compounds, phenolic acids, flavonoids, and anthocyanins as well as antioxidant activity (radical scavenging ability against DPPH and ABTS • and chelating power Fe2 ) were determined in raspberry juices (obtained after enzymatic treatment with three commercial pectinolytic enzyme preparations) and syrups (obtained by the addition of sucrose at concentrations of 30% and 70%) during storage. Results. During the five-month storage of juices and syrups at room temperature, there was significant reduction in the level of phenolic compounds, in particular anthocyanins (up to 95% in relation to the initial content). Storage of raspberry juices and syrups also resulted in a reduction in antioxidant activity. Conclusions. The enzymatic treatment of the raspberry mash generally increased the losses of anthocyanins. The addition of sugar to fruit juices only slightly reduced these losses.
