Evaluation of phenolic content and antioxidant capacity of blueberry cultivars (Vaccinium corymbosum L.) grown in the Northwest Croatia.

Summary The aim of this study is to evaluate the content of phenolics: total phenols (TPC), flavonoids (TF), anthocyanins (TA), flavan-3-ols (TF3ols), as well as total antioxidant capacity (TAC) and reducing power (RP) in four blueberry cultivars (Vaccinium corymbosum L.) introduced in the Northwest Croatian climate conditions. Phenolic compounds were measured by spectrophotometric methods, TAC was determined using DPPH and ABTS assays and RP by FRAP assay. All cultivars contained high mass fraction of TPC, TF, TA and lower mass fraction of TF3ols. Among the researched fruits, Sierra cultivar contained the highest amounts of all groups of phenolics, followed by Elliott>Bluecrop³Duke. Significant differences were observed in phenolic mass fraction among different cultivars and growing seasons (p<0.05), and phenolic compounds were significantly higher in growing season 2006. Examined cultivars possess high antioxidant capacity and reducing power, and all phenolics were highly correlated with TAC and RP (R=0.46 to 0.99). The study indicated that growing and climate conditions in Northwest Croatia are convenient for introducing blueberry cultivars. Generally, blueberry fruits are a rich source of phenolics, which show evident antioxidant capacity.