The Effects of NaCl on Starch Molecular Conformation

Starch is one of the most important renewable resources in nature. It has been found that NaCl has significant effects on starch properties, but the effect mechanism has not been fully clarified yet. In this study, molecular dynamics simulation is used to explore the effects of NaCl on starch molecular conformation, molecular stability, and secondary interactions. The results show, firstly, NaCl can significantly increase the electrostatic attraction, then decrease the Rg, SASA, spiral pitches, end-to-end distances, and interchain distances of starch molecules, and make starch molecules more compact. Secondly, NaCl can decrease the RMSD and RMSF values, and reduce the movement of starch molecules. Thirdly, NaCl can increase the binding free energy, and make starch molecules stable, which may be one of the reasons why high NaCl concentration can accelerate the destruction of starch granule structure. Fourthly, NaCl can enhance the hydration of starch molecules, which may be the key reason why a high NaCl concentration can promote starch gelatinization. The results may provide new insights for the research and mechanism exploration of the interaction between NaCl and starch.