Ultrasound assisted extraction in aqueous two-phase system for the integrated extraction and separation of antioxidants from wheat chaff

A procedure for simultaneous extraction and separation of xylooligosaccharides and phenol compounds from wheat chaff by ultrasound assisted ethanol/ammonium sulfate aqueous two-phase extraction was studied. In aqueous two-phase system 23.8% (w/w) salt, 24.3% (w/w) ethanol and 1.2% (w/w) solids load using ultrasound waves (30 Hz, 500 W, 10 min), extraction yields of sugars and phenols were 16 mg/g and 2.67 mg/g dry material, respectively. Under these conditions xylooligosaccharides and phenol compounds partitioned toward the bottom and the top phase, respectively, and selectivity of their separation was almost 50. The bottom phase with recovered 96% extracted sugars and the top phase containing 64% extracted phenols expressed 0.45 μmol TE/g and 1.1 μmol TE/g ABTS radical-scavenging activities, respectively. Result indicated that ultrasound assisted aqueous two-phase extraction in ethanol/ammonium sulfate system could be a promising technique for integrated extraction and separation of bioactive components from wheat chaff.