Investigation and optimization of the purification process of anthocyanins from Aronia melanocarpa (L.) Nieuwl.

In this study, an ultrasound-assisted deep eutectic solvent was used to extract anthocyanins from Aronia melanocarpa (L.) Nieuwl. 1,2-Propanediol, glycerol, lactic acid, citric acid and glucose were used as hydrogen bond donors (HBS) and acceptors. A choline chloride (HBA) eutectic reaction was performed according to the extraction rate of anthocyanins to characterize the deep eutectic solvent. The results revealed that the optimal solvent raw materials were choline chloride and glycerol, and the optimum extraction conditions were: ultrasonic treatment power of 165 W, time of 20 min, and solvent moisture content of 40%. Under these conditions, the extraction amount of anthocyanin was 42.541 ± 0.15 mg/g, close to the prediction of the regression model (42.555 mg/g). The model analysis revealed that ultrasonic power demonstrated the most significant impact on extraction yield (F = 572.095, p < 0.0001), followed by ultrasonic duration and moisture content. During purification, UV scanning identified 540 nm as the optimal absorption wavelength for anthocyanins. Comparative studies of three macroporous resins (X-5, AB-8, polyacrylamide) showed X-5 resin exhibited superior performance in static adsorption, achieving equilibrium within 1 hour with high desorption efficiency. In dynamic elution, X-5 reached peak absorbance at 10 mL elution volume, outperforming polyacrylamide. Consequently, X-5 resin was selected as the purification medium with 80% ethanol eluent, which maximized anthocyanin desorption stability. This study establishes an efficient and environmentally friendly extraction-purification process for Aronia melanocarpa anthocyanins, providing robust theoretical foundations and technical support for industrial development with significant application potential.