New ultrasound-assisted extraction methods for the determination of anthocyanins and total phenolic compounds present in mulberries have been developed. Several extraction variables, including methanol composition (50-100%), temperature (10-70°C), ultrasound amplitude (30-70%), cycle (0.2-0.7s), solvent pH (3-7) and solvent-solid ratio (10:1.5-20:1.5) were optimized. A Box-Behnken design in conjunction with a response surface methodology was employed to optimize the conditions for the maximum response based on 54 different experiments. Two response variables were considered: total anthocyanins and total phenolic compounds. Extraction temperature and solvent composition were found to be the most influential parameters for anthocyanins (48°C and 76%) and phenolic compounds (64°C and 61%). The developed methods showed high reproducibility and repeatability (RSD<5%). Finally, the new methods were successfully applied to real samples in order to investigate the presence of anthocyanins and total phenolic compounds in several mulberry jams.
Keywords: Anthocyanins; Box–Behnken design; Cyanidin-3-O-(6″-dioxalyl-glucoside) (PubChem CID: 44256830); Cyanidin-3-O-(6″-malonyl-glucoside) (PubChem CID: 44256740); Cyanidin-3-O-glucoside (PubChem CID: 12303203); Cyanidin-3-O-rutinoside (PubChem CID: 44256716); Mulberry; Phenolic compounds; Ultrasound-assisted extraction.
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