Polyethylene glycol as a novel solvent for extraction of crude polysaccharides from pericarpium granati

Polyethylene glycol aqueous solution (PEGs), an environmentally friendly solvent was used, for the first time, to develop an extraction method for crude polysaccharides from pericarpium granati with ultrasonic–microwave-assisted extraction (UMAE). Compared with other extraction solvents, PEGs, especially PEG400, displayed a higher extraction yield. The extraction conditions were an ultrasonic power of 240 W, a microwave power of 365 W, a PEG400 concentration of 30% and a ratio of liquid to raw material of 20 mL/g, optimized by using Box–Behnken experimental design. Under these conditions, an extraction yield of 7.94 ± 0.3% (n = 3) was obtained, which is about 25% higher than that with water as a solvent, and the polysaccharides content in pericarpium granati was 6.56 ± 0.01 mg/g expressed as glucose.