Abstract:

The ultrasound-assisted aqueous two-phase extraction of tea polyphenols was optimized using response surface
methodology. The extraction parameters ethanol concentration, ammonium sulfate concentration, solvent-to-solid ratio, ultrasound
treatment time and temperature were used as independent variables to investigate their effects on the extraction yield of tea
polyphenols. Results indicated that the optimal extraction conditions were found as follows: ultrasound-assisted extraction was
conducted at 45 ℃ for 16 min using an aqueous two-phase system consisting 0.25 g/mL of ammonium sulfate in 50% aqueous
ethanol at a solvent-to-solid ratio of 70:1 (mL/g). The yield of tea polyphenols under these conditions was 17.58%.

Key words: ultrasound, ethanol, ammonium sulfate, aqueous two-phase system, tea polyphenols