To avoid wasting blueberry pomace resources, deep eutectic solvents (DESs) were combined with ultrasound technology to establish an efficient green method for the recovery of anthocyanins and polyphenols from plant-derived by-products. Choline chloride:1,4-butanediol (molar ratio of 1:3) was chosen as the optimal solvent based on the screening of eight solvents and single-factor experiments. Response surface methodology was applied to optimize the extraction parameters: water content, 29%; extraction temperature, 63 °C; liquid-solid ratio, 36:1 (v/w). The yields of total anthocyanins and total polyphenols from the optimized extraction were 11.40 ± 0.14 mg cyanidin-3-glucoside equiv./g and 41.56 ± 0.17 mg gallic acid equiv./g, respectively, which were both significantly better than the yields achieved with 70% ethanol. The purified anthocyanins showed excellent inhibition of α-glucosidase (IC50 = 16.57 μg/mL). The physicochemical parameters of DES suggest that it can be used for the extraction of bioactive substances.
Keywords: Anthocyanins; Deep eutectic solvent; Polyphenols; Response surface methodology; α-glucosidase activity.
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