Optimation of enrichment and purification of polyphenols from blueberries (Vaccinium spp.) by macroporous resins XAD-7HP

Abstract

Blueberries are rich sources of phenolic compounds and exhibit strong antioxidant activities and a wide variety of biological activities. 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. 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. 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.