Optimization of ultrasound-assisted aqueous two-phase system (ATPS) of phenolics from apple pulp and peel

In this study, extraction of phenolic compounds from apple peel and pulp was optimized using an ultrasound-assisted aqueous two-phase system (UA-ATPS) consisting of acetone-NaH₂PO₄ and acetone-(NH₄)₂SO₄ with the help of Response Surface Methodology. The effectiveness of UA-ATPS was compared with certain extraction methods including traditional aqueous two-phase system (T-ATPS), ultrasound-assisted acetone extraction (UA-ACE) and traditional acetone extraction (T-ACE). The UA-ATPS gave better results than traditional methods in terms of phenolic and flavonoid contents and antioxidant activity values regardless of the fruit parts used. The status of extraction yield was observed with three major phenolics of apple including chlorogenic acid, rutin and phloridzin. Striking increases in chlorogenic acid and rutin contents in the peel were determined when acetone was replaced with ATPS in the same extraction system with equal extraction time (20 min). The present study has indicated that UA-ATPS is an effective method for phenolic extraction from apple peel and pulp.