Investigation on high-value bioactive compounds and antioxidant properties of blackberries and their fractions obtained by home-scale juice processing

Abstract

Blackberry pomace represents a valuable but underused byproduct of juice manufacturing. Its further applicability in various food systems is facilitated by detailed knowledge of its own bioactive potential. This study was focused on the investigation of the polyphenolic compound profile, total phenolic and ascorbic acid content, as well as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of blackberries (Rubus fruticosus L.) coming from spontaneous flora of two different areas of Romania, Paltinis (Sibiu County) and Zugau (Arad County) and their fractions, juice and pomace, resulting from home-scale processing. To ensure a satisfactory shelf life, the blackberry pomace was subjected to convective drying (60 °C for 12 hours) and the impact of this treatment on the antioxidant properties was evaluated. No significant differences in the investigated characteristics according to the place of origin were recorded. However, a slight increase in the antioxidant properties of fruits and fractions from the Zugau region, characterized by higher temperatures and a lower precipitation regime, was noticed compared with samples derived from the Paltinis area. The drying of blackberry byproducts led to losses of 10-23% in the content of the investigated bioactive compounds and DPPH radical scavenging activity. A significant correlation between DPPH radical scavenging activity and the total phenolic content has been recorded. Our findings are of interest in blackberry selection to enhance the level of bioactive compounds in the targeted products. The obtained results confirm that the blackberry processing byproducts may be regarded as a promising source of high-quality bioactive compounds and a proven radical scavenging capacity, representing a starting point for further analyses. This study responds to a global issue regarding fruit byproduct management in order to ensure the sustainable development of a circular economy.