Antioxidants content in commercial blackcurrant juice products
Katarzyna Włodarska and Ewa Sikorska
Faculty of Commodity Science, Poznań University of Economics and Business, al. Niepodległości 10, 61-875, Poznań, POL
Juices from blackcurrant have been shown to have strong antioxidant capacities because of high content of natural antioxidants such as polyphenols and vitamin C. Polyphenol-rich products exhibit a number of health-supporting properties including reduction of the negative effects of oxidative stress and the risk of cardiovascular diseases. The aim was to study the variation in antioxidants content between commercial blackcurrant products with different juice content. The total content of phenolic compounds and contents of groups of phenols – flavonoids and anthocyanins, were measured using spectrophotometric methods. Content of vitamin C was measured by HPLC and antioxidant capacity of juices studied was quantified by the TEAC assay. Differences in antioxidants content between juices and nectars from blackcurrant were significant (p < 0.05) within all parameters analyzed. The average content of polyphenols in 100 % juices was 2513 mg/L and ranged from 2215 to 2987 mg/L, whereas in nectars with 25 % content of juice was 912 mg/L (822-1101 mg/L). Contents of flavonoids and anthocyanins in juices were on average 712 and 48 mg/L, whereas in nectars 215 and 31 mg/L, respectively. 100 % blackcurrant juices are a rich source of vitamin C, measured values ranged from 125 to 266 mg/L, for comparison in nectars on average 63 mg/L. Also significant differences in antioxidant capacity between juices and nectars were observed. The relationship between TEAC value and contents of antioxidants was determined. The antioxidant capacity of blackcurrant juice products significantly depends on their total phenolic content and total flavonoids content, correlation coefficients R2 = 0.859 and 0.789, respectively.
National Science Centre, Poland, is gratefully acknowledged for the financial support (project no: 2016/23/B/NZ9/03591).