Influence of shading net on polyphenol profile and radical scavenging activity in different varieties of black currant berries

Abstract

Changes of environmental factors, created under influence of various shading nets, could significantly affect some pomological and organoleptic characteristics of plants grown in such conditions as well as biosynthesis of phenolic compounds. Five black currant cultivars Ben Sarek, Ben Nevis, Ben Lomond, Ometa, and Cacanska crna were cultivated either in the shade of green polyethylene nets or exposed to direct sunlight during two experimental seasons. All berries in the control treatment (without shading nets) contained higher amounts of total phenolics in both experimental seasons: 474-520 mg GAE/100 g in 2010, and in 2011 it ranged from 401 to 501 mg GAE/100 g. Similar but less expressed trend was noticed regarding anthocyanins content. Growing in shade generally led to a lower content of flavonoid, phenolic acid and anthocyanin compounds, determined by HPLC/MS. Despite the reduction of phenolic compounds content, all tested varieties expressed significant radical scavenging activity against DPPH radical, and differences in antiradical activity were statistically significant only between varieties.