Antioxidant activity and phenolic content of organic and conventional vine cane extracts

Abstract

Phenolic antioxidants, such as resveratrol and polydatin, occur in grapevine as secondary metabolites responsible for the plants protection against biotic and abiotic stress. The antioxidant profile and content depends on agro-climatic conditions, which may act as stress factors. In order to determine the significance of the use of spraying pesticides on the antioxidant content in pruned canes, we examined samples of white and blue Vitis vinifera varieties from conventional and organic vineyards. Phenols from these samples were extracted by 40% ethanol. HPLC was used to determine differences in the stilbenoid composition and the DPPH assay was used to compare the antioxidant activities. While the farming approach did not alter the total polyphenolic content and antioxidant activity of the samples, the resveratrol content was higher in samples from conventional vineyards. These results could be significant for further reusing of winery waste.