Abstract

Introduction: Blueberries are rich sources of phenolic compounds and exhibit strong antioxidant activities and a wide variety of biological activities.
Methods: Polyphenols were extracted from blueberry by solvent extraction method using ethanol solution. The purification of polyphenols from blueberries (Vaccinium spp.) by macroporous resin XAD-7HP was optimized by adsorption and desorption tests. The cellular antioxidant activities of the purified polyphenols were investigated.
Results: The adsorption data indicated that the process was best explained by the Langmuir isotherm model. The best conditions were determined as: blueberry polyphenols concentration, 2.00 mg/g; pH 2.0; ethanol desorption solution concentration, 70 % (v/v); flow rates for feeding and elution, 1 and 2 bed volume (BV)/h, respectively; and a water wash volume of 3 BV. Under these conditions, the purity of the blueberry polyphenols was improved from 46.3 to 86.48 %. The EC50 (concentration for 50 % of maximal effect) and CAA (cellular antioxidant activity) values of the blueberry polyphenols were 151.58 mg/mL and 6.39 µmol QE /100 g sample, respectively.
Conclusion: The results demonstrate that purification of polyphenols by macroporous resins XAD-7HP will provide foundation for the development of large-scale separation of blueberry polyphenols in industry.

Key words: Blueberry (Vaccinium spp.); polyphenol; macroporous resin XAD-7HP; purification; cellular antioxidant activity (CAA)