Ultrasound-assisted extraction of anthocyanins and phenolics from jabuticaba (Myrciaria cauliflora) peel: kinetics and mathematical modeling

Jabuticaba (Myrciaria cauliflora) is a dark berry, endemic to the south and central regions of South America, rich in anthocyanins and polyphenols. This study evaluated the ultrasound-assisted extraction of bioactive compounds from jabuticaba peel, developed a new mathematical model for the process, and estimated the model parameters. Extraction was carried out using water as solvent aiming its direct use in food formulations. The main anthocyanin (cyanidin-3-O-glucoside) and the main polyphenol (ellagic acid) from jabuticaba peel were extracted and quantified by LC–MS and HPLC. The results indicate that lowering the pH increased the extraction of the anthocyanin and had only slight effect on the extraction of ellagic acid. The application of ultrasound at 25 kHz favored the extraction of both compounds. Processing time of 20 min increased the yield of both compounds, while over processing (> 20 min) let to the sonochemical-induced hydrolysis of cyanidin-3-O-glucoside and ellagic acid. The highest yield of bioactive compounds was attained at 25 kHz, 20 min of extraction and pH 1.5 (8.9 mg/g dry peel of gallic acid equivalent, 0.9 mg/g dry peel of ellagic acid, and 7.9 mg/g dry peel of cyanidin-3-O-glucoside). The new mathematical model considered the mass transfer between the powder and the liquid media, and the sonochemical-induced hydrolysis of the compound. The model was able to predict satisfactorily the extraction process and the hydrolysis effect.