Water-soluble polysaccharide from wampee(WSP-W)was prepared through water extraction then precipitation by ethanol,and compounded with chitosan to make WSP-W/chitosan composite edible films.The molecular weight,chemical composition and infrared spectrum of WSP-W were preliminarily examined,and the effect of WSP-W on the WSP-W/chitosan composite edible film was investigated.The results showed that WSP-W was a typical homogeneous polysaccharide,with a molecular weight of 1.6x103 ku.When different concentrations of WSP-W were added,fourier transform infrared spectroscopy demonstrated that The amino band of chitosan molecule in FT-IR spectra shifted from 1 560.1 cm-1 to 1 571.7 cm-1 for the composite film,indicating that there was an interaction between WSP-W and chitosan.Compared with the film made with chitosan singly,the composite films exhibited increased thickness,water solubility and swelling rate but a decreased moisture content.In terms of optical transmittance,the composite films showed strong UV barrier capability at a wavelength below 500 nm.The results of the mechanical property tests showed that when the WSP-W content was 12％,the tensile strength and elongation at break reached the maximum(30.13 MPa and 29.93％,respectively).The water vapor permeability reached 24.54 g·mm/(m2·d·kPa)when WSP-W was 12％,and the oil resistance capacity reached 96.24 g·mm/(m2·d)when WSP-W was 6％.DSC results revealed that the thermal stability of the composite films was better.The results of the DPPH and hydroxyl radical scavenging rates showed that WSP-W could improve the film's antioxidant activity.In summary,the addition of WSP-W can improve the optical,mechanical,barrie and antioxidant properties of chitosan film,which can provide a certain reference for the development and utilization of WSP.
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