添加脱支淀粉改进蜡质玉米淀粉膜性能的研究

In this study, different proportions of debranched waxy maize starch (DWMS) were added to waxy maize starchs to improve properties of waxy maize starch based films. The effects of DWMS proportion and relative humidity (RH) in the film formation on the starch films properties were studied. The properties of the starch films were measured by light microscope, X- ray diffraction and texture analyzer. Phase separations were observed in mixed films by light microscope. With the increase of humidity, the film crystallinity and the tensile strength (TS) were increased, where as the elongation at break (E) and the water vapor permeability (WVP) were decreased. The crystallinity of starch film was increased when the DWMS addition was increased from 0% to 15%; but it was decreased when DWMS increased to 25%; and further increase of DWMS addition resulted the failure in film formation. The crystallinity of starch film was positively correlated with TS (r=0.902), and negatively correlated with E (r=-0.809). The best mixed starch film obtained in this study contains 15% DWMS and formed in 85% RH: compared to the best waxy corn starch films, its TS increased 75.8%, E reduced 49.1% and WVP reduced 21.50%; compared to the best normal corn starch films, its TS and E were increased 42.6%, and 11.4% respectively, while WVP was reduced 5.33%.