分子动力学模拟水分对直链淀粉扩散性质和玻璃态转变温度的影响  

Effect of Moisture Content on Diffusion Properties and Glass Transition Temperature of Amylose by Molecular Dynamics Simulation

作　　者：官斌[1,2] 钟业俊[1] 

机构地区：[1]南昌大学食品科学与技术国家重点实验室,南昌330047 [2]江西省质量技术监督行政许可评审中心,南昌330047

出　　处：《中国粮油学报》2015年第4期18-22,共5页Journal of the Chinese Cereals and Oils Association

基　　金："十二五"国家科技支撑计划(2012BAD37B02)

摘　　要：为了预测水分对直链淀粉玻璃态温度、径向分布函数和扩散系数的影响，在COMPASS力场和等温等压（NPT）系综下，利用分子动力学模拟方法，模拟得到了不同水分含量直链淀粉在298K下的径向分布函数和扩散系数；在200～460K温度范围内，通过模拟获得不同温度下的比体积，与对应的温度作图，研究了水分对直链淀粉玻璃态转变行为的影响。结果表明，所构建的直链淀粉模型属于一种无定型结构，其径向分布函数的形状和峰位基本没有发生变化。随着水分含量的增加，水分子更容易在直链淀粉中扩散，与直链淀粉分子发生相互作用的概率增大。水分含量对直链淀粉玻璃态转变行为影响显著，水分含量越高，直链淀粉的玻璃态转变温度越低。Under the COMPASS force field and NPT statistical as diffusion coefficient of amylose had been studied under 298 K by ensemble, the radial distribution function as well molecular dynamics （MD） simulation. The glass transition temperature （Tg） of amylose had been obtained in the range 200 - 460 K through plotted the specific volume -temperature curve in differential moisture content. The results indicated that the amylose models belonged to amorphous structure and no significant alteration expressed on the peak shapes and the position of radial distribution function. Along with the increase of moisture content, the water molecules were easier to interact with amylose structure and the effects of moisture content on decreasing of Ts of amylose were significant.

关 键 词：分子动力学 玻璃态转变温度 直链淀粉 径向分布函数 

分 类 号：TS231[轻工技术与工程—粮食、油脂及植物蛋白工程]