Composition and antioxidant activity of polysaccharides from jujuba by classical and ultrasound extraction

• The extractability of crude Zizyphus jujuba cv. Junzao polysaccharides was significantly enhanced by the ultrasound treatment.
• CZPU contained more glucose than CZPH.
• CZPU showed stronger antioxidant activities compared with CZPH.

Crude Zizyphus Jujuba cv. Junzao polysaccharides (CZP) were extracted by hot water and ultrasound-assisted extraction respectively. Using a short application of ultrasound, the yield of polysaccharides increased from 6.23 to 7.95%, which represents an increase of about 27.6%. Both CZPU and CZPH were composed of arabinose, rhamnose, glucose, galactose, and mannose. However, the molar ratio of CZPU was 5.46: 4.96: 5.17: 2.63: 1, while it was 5.46: 4.89: 3.65: 2.54: 1 for CZPH. Furthermore, CZPU had stronger antioxidant activities than CZPH by evaluating in hydroxyl radical and ferric-reducing antioxidant power (FRAP) assay.