Molecular Dynamics On The Stable Gel Of Konjac Glucomannan And Sodium Alginate

Konjac glucomannan(KGM)is one kind of water soluble and non-ionic polysaccharide including in konjak.tuber,which is widely used in food and medicine fields due to its unique properties.Its research in structure activity relationships slowly,because of its complexity of structure.The domestic and foreign research mainly concentrated in the thermal reversible reaction of gel,compound characteristics and physical modification.KGM mixing with other macromolecular material can improve its physical and chemical properties and form synergistic interaction.But recent relevant research never expound its interaction in the terms of molecular structure.In this paper,gel of KGM and sodium alginate were research to explain the energy change,the hydrogen bond and some physical parameters in solution of compound,aiming to provide a theoretical basis to complex gel application.(1)The energy change,conformation and H-bond number of KGM and sodium alginate were studied in this experiment,after have constructed and optimized molecular model.The results suggest that there are a number of H-bond exist between KGM and sodium alginate.H-bond mainly found at-OH groups on C(6)and C(3)of KGM,C(2)and C(3)of sodium alginate.The conformation and energy of compound tend to be stable in the process of simulation.(2)The comparison of surface area between KGM and sodium alginate was 930·1 A2 and 655.5A2 smaller,Which suggest that the compound's surface area is smaller comparing with each one,which indicate that compound is more stable.(3)The physical parameters of compound,including mean square displacement,radius of gyration and none-bonded function,were studied in this experiment.The research show that H-bond contribute most among Vdw,Electrostatic and H-bond;the motion of compound molecules were limited under water solution;the radius of gyration of compound arrange from 9.160A to 9.180A.Above all indicate that the conformation of compound is stable.(4)The radial distribution function was calculated to investigate water molecule distribute rule and the effect of adding Ca2+.The research indicated that KGM molecules were surrounded by water molecule at the distance of 1.6A and 2.6A,which also indicate strong H-bond was existing.The coordination complexes between The oxygen atom of compound and calcium was also existing,adding Ca2+help forming stable gel.(5)To investigate the intensity and constructure change of compound gel,mixed ratio,temperature and pH were studied in in this experiment.The research indicated that compound gel is high strength,elastic and thermal reversible.The compound is better than KGM in viscosity off liquid contraction.The infrared spectrum analysis show that H-bond of compound was enhanced.