以甘油为增塑剂,普兰多糖为黏合增强剂,采用熔融共混挤出技术制备热塑性淀粉,再挤出吹塑制备淀粉基可食膜。研究甘油对热塑性淀粉流变性、玻璃化转变温度、相变焓和微观形貌的影响;并研究了湿度环境对可食膜力学性能的影响及甘油对淀粉可食膜力学性能及热稳定性的影响。结果表明:甘油能有效的改善了热塑性淀粉的流变性和微观结构,降低热塑性淀粉的玻璃化转变温度,使淀粉结晶熔融焓变减小。实验制备的热塑性淀粉膜适宜在湿度40%的环境下使用;且在该湿度条件下,甘油添加量28%时,淀粉可食膜的纵向拉伸强度为5.26 MPa,断裂伸长率达到137.9%,横向拉伸强度为4.92 MPa,断裂伸长率为118.0%。

A thermoplastic starch was prepared by melting processing method using glycerol as a plasticizer and pullulan as an adhesion reinforcing agent.Edible film was prepared by using extrusion blow molding.The effect of glycerol on rheological behavior,glass-transition temperature,enthalpy of phase change and microstructure was investigated.The effect of ambient humidity on mechanical property and thermal stability were studied.The result showed that glycerol can improve the rheological behavior and microstructure of the thermoplastic starch,reduce the glass-transition temperature and enthalpy of phase change.The edible film was suitable under 40% ambient humidity.Under this humidity,with 28% glycerin,the portrait tensile strength of the edible starch film was 5.26 MPa,portrait elongation at break was 137.9 %;transverse tensile strength was 4.92 MPa,transverse elongation at break was 118.0%.