基于分子动力学模拟的直链淀粉风味分子包合物形成机理的研究

Mechanism of Amylose-flavor Molecule-inclusion Compound Formation Simulated By Molecular Dynamics

摘要:

本研究借助Gromacs软件，利用葡萄糖分子力场对直链淀粉的分子构型、在水溶液中的折叠及其与正己醇、正庚醇、正辛醇等三种小分子醇类包合物的形成过程进行了模拟，并将试验结果与之前的表征进行对比，阐明了V型直链淀粉包合物的形成机理以及直链淀粉分子与客体风味分子之间的相互作用关系。直链淀粉在水溶液中呈现出自由舒展的螺旋线圈形状，该形状在一定的范围内随着含水量的下降而更加明显。在直链淀粉与醇类分子形成包合物的模拟过程中，均方根偏差（RMSD）变化趋势类似，均是随着温度的升高逐渐升高，表明包合物体系变化宏观表现一致，但氢键数目、分子间力截程分布、系统电势等均因客体分子的不同而不同。综合各个参数，分子动力学模拟可在分子水平上对包合物形成的可能性预测提供有力的依据，并证实直链淀粉会随着客体分子的变化而变化，形成结构相对稳定的包合物。

Abstract:

In this study, glucose molecular force field and Gromacs software were used to simulate the molecular conformation of amylose, its folding in aqueous solution, and the process of formation of inclusion compounds with three small alcohol molecules, n-hexanol, n-heptanol, and n-octanol. The results were compared with previous experimental characterization to clarify the mechanism of formation of the V-shaped amylose inclusion compounds and the interactions between amylose and guest molecules contributing flavor. Amylose exhibits a free stretch of spiral coil configuration in aqueous solution, which is more obvious with a decrease of water content within a certain range. In the stimulated formation of inclusion compounds with alcohol molecules, the changing trends of root mean square deviation (RMSD) were similar, showing a corresponding increase with a rise in temperature. This shows that the inclusion compound system had a consistent macro appearance; however, the number of hydrogen bonds, the cutting process distribution of intermolecular forces, system electric potential, and so on varied between target molecules. Putting all the parameters together, the molecular dynamics simulation can provide strong evidence to predict the possibility of inclusion formation at a molecular level. It also confirms that amylose combines with other molecules to form relatively stable inclusion configurations.