Ultrasonic-assisted enzymatic extraction and identification of anthocyanin components from mulberry wine residues

Mulberry wine residues produced during the wine-brewing process contain several anthocyanins and other bioactive compounds. Therefore this study optimized the conditions for ultrasound-assisted enzymatic extraction of anthocyanins from mulberry wine residues. A three-level, four-factor Box-Behnken design was used to optimize the extraction conditions. Moreover, anthocyanins were determined using an ultra-performance liquid chromatograph coupled to a mass spectrometer (UPLC-MS). The mathematical model suggested a high coefficient of determination (R-2 = 0.9475) for the optimum conditions, namely 52 degrees C, 315 W, 0.22% enzyme and 94 min incubation. The yield (5.98 mg/g) was close to the predicted value (5.87 mg/g). The two anthocyanins (cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside) identified are consistent with those present in mulberry. The optimized conditions increased anthocyanin yield, through improved utilization of mulberry wine residues. The findings will potentially lead to a reduction in the environmental burden of this waste and improve the efficiency and productivity of the mulberry fruit processing industry.