The key role of grape variety for antioxidant capacity of red wines

Abstract

summary Background & aims: Recent epidemiological studies have supported the idea that food rich in plant bioactive compounds and polyphenols in particular may exert beneficial effects toward human health. One of the foodstuffs widely distributed in the human diet is red wine, a strong antioxidant that contains many bioactive compounds, such as: polyphenols, minerals, and vitamins. The objective of this study was therefore to assess the antioxidant capacity, total phenolics, selected vitamin and mineral content in red wine samples and also to elucidate the existence of a possible relationship between grape variety and all constituents of wines as mentioned above. Methods: The set of 10 red wines, six of Cabernet Sauvignon and four of Merlot was subjected to the study. In all samples total antioxidant capacity was measured by Trolox equivalent antioxidant capacity (TEAC) assay and the Ferric reducing ability of plasma (FRAP) assay simultaneously with total phenolic content, selected minerals and essential vitamins. Results: Both antioxidant capacity and phenolic content were higher in Cabernet Sauvignon wines compared to Merlot. The total antioxidant capacity correlated positively with total phenolic content (r ¼ 0.88, p < 0.001 for TEAC assay and r ¼ 0.89, p < 0.001 for FRAP assay respectively), while a significant relationship among antioxidant capacity, selected minerals and vitamins was not observed. Among the nine minerals analyzed, potassium, zinc and magnesium were the most abundant elements distributed throughout all wine samples. Our results suggest that antioxidant capacity is dependent mainly on total phenolics. Grape variety largely determines such components as phenolic content, antioxidant capacity and mineral content with the exception of vitamins.