Xiao Qian, Lim Loong-Tak, Tong Qunyi
State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Jiangsu, China; School of Food Science and Technology, Jiangnan University, 214122 Jiangsu, China.
Department of Food Science, University of Guelph, N1G 2W1 Ontario, Canada.
Carbohydr Polym. 2012 Jan 4;87(1):227-234. doi: 10.1016/j.carbpol.2011.07.040. Epub 2011 Jul 30.
Pullulan-sodium alginate blend films were prepared and characterized as a function of water activity (a). At low a, the incorporation of alginate into pullulan film increased the tensile strength and elastic modulus, but decreased the elongation at break of the composite films; the opposite trends were observed at elevated a. Above 0.43 a, water exerted a typical plasticization effect upon the biopolymer blends. As a increased from 0.23 to 0.43, an anti-plasticization effect was observed as tensile strength and elastic modulus increased. The glass transition temperature of all samples decreased substantially as aw increased from 0.23 to 0.84 due to the plasticization effect of water. Within this a range, one transition temperature was observed for all film specimens. The stretching vibration band of O-H was investigated using attenuated total reflection Fourier transform infrared spectroscopy to identify the various species of water interacting with the polysaccharide films.
制备了普鲁兰多糖-海藻酸钠共混膜，并对其作为水分活度（a）的函数进行了表征。在低水分活度下，将海藻酸钠掺入普鲁兰多糖膜中可提高拉伸强度和弹性模量，但会降低复合膜的断裂伸长率；在较高水分活度下观察到相反的趋势。在水分活度高于0.43时，水对生物聚合物共混物产生典型的增塑作用。当水分活度从0.23增加到0.43时，观察到抗增塑作用，因为拉伸强度和弹性模量增加。由于水的增塑作用，当水分活度从0.23增加到0.84时，所有样品的玻璃化转变温度大幅下降。在此水分活度范围内，所有薄膜样品均观察到一个转变温度。使用衰减全反射傅里叶变换红外光谱研究了O-H的伸缩振动带，以确定与多糖膜相互作用的各种水分子。
