The antioxidant properties of anthocyanins in different Aronia products
Oxidative stress is an important risk factor in pathogenesis of numerous diseases including atherosclerosis and cancer. Accordingly, the dietary and medicinal intervention decreasing reactive oxygen species (ROS) exposition became hot field of research. Aronia (Aronia melanocarpa E.), belonging to the Rosaceae family, has received much attention in this regard owing to its high antioxidative potency attributed to poliphenolic compounds, mainly anthocyanins (pigments accounting for the dark blue and even black colour of fruits). It can be expected however that processing may influence antioxidant activity and anthocyanin content of final Aronia products reaching consumers. The aim of this study was to compare different Aronia products (fresh fruits from different sources, syrups, infusions) in relation to their antioxidant activity and anthocyanin content.
The samples were standardized by color intensity measured spectrophotometrically. The total content of anthocyanins was determined by pH-differential spectrophotometry. Several tests were applied to assess antioxidant potency: Folin-Ciocalteu, ABTS, DPPH and ORAC. The highest antioxidant capacity was detected for fresh fruits and ranged from 200 to 800µmol Trolox equivalents (TE)/g of dry weight (dw) depending on test used. The lowest antioxidant activity was obtained for Aronia jam (1–28µmol TE/g dw depending on test). The results obtained by methods: Folin-Ciocalteu, ABTS, DPPH and ORAC were highly correlated with each other but not necessarily with anthocyanin content. These results will be used in future research on design of Aronia products with optimized antioxidant properties, that could be offered to general public and also recommended to patients to support treatment.