Ultrasound-assisted extraction and adsorption of polyphenols from Ginger Rhizome (Zingiber officinale)

Ultrasound-assisted extraction followed by adsorption and desorption was performed successively for efficient recovery of polyphenols from ginger rhizome (Zingiber officinale). The maximum degree of extraction was observed in case of methanol (0.55 mg/ml) followed by acetone (0.52 mg/ml) and ethanol (0.37 mg/ml). At optimized conditions, the polyphenol recovery was found to be 19.2 mg. Amberlite XAD4 had shown the highest adsorption capacity (0.89 mg/ml). Kinetic studies indicated the adsorption equilibrium to be about 20 min. Adsorption capacity was achieved at 25 ± 2°C, and adsorption process exhibited exothermic nature. Freundlich isotherm fitted the data well. Ethanol had shown best desorption efficiency (93.44%).