Molecular Dynamics Simulations of the Interactions Between Konjac Glucomannan and Soy Protein Isolate

The interactions between konjac glucomannan(KGM) and soy protein isolate (SPI) were studied with the method of molecular dynamics simulation. Part representative structures segments of KGM and SPI were used as mode, and the force-field was FF03. The stability and sites of KGM/SPI interactions in water were researched at 363 K with the following results: the potential energy (EPOT) of the mixed gel dropped, while that of single KGM gel increased. The surface area (SA) of KGM in the mixed system was decreased to 401.41 from 1 267.54 Å2, and that of SPI to 484.94 from 1 943.28 Å2. The sum potential energy of KGM and soy protein in the mixed system was decreased to −13 402.41 from −5 768.56 kcal mol−1. The variations of two parameters showed that the stability of compound gel KGM/SPI was improved, which was consistent with the previous studies. The sites of interactions in the mixed gel were the −OH groups on C(2) in KGM mannose and glucose, and the amide linkage group on Histidine, Asparagine and Leucine in SPI. The hydrogen bond was formed directly or indirectly by the bridge of waters.