Molecular dynamics of triglycerides: atomistic and coarse-grained approaches

The objective of this thesis have been the development and the analysis of microscopic mathematical models to investigate the dependence of triglycerides conformations from environmental conditions. Triglycerides are important constituents of food products that show polymorphic solid transitions. Such behaviors influence greatly processes management involving fats mixtures. To investigate the relationship between macroscopic conditions and conformational induced properties, we dealt with microscopic mathematical models. The first part of the thesis regards the building of a united-atoms model from which physical properties and structural distribution functions of a liquid phase were derived. The second part regards the development of a coarse-grained model. The force field of such model was developed, by means of statistical tools, using suitable distribution functions derived from the atomistic one. The coarse-grained model was used to perform numerical experiments to highlight the dependence of molecules conformations from experimental conditions. The results of our simulations show a clear relationship between the conformational state of molecules and temperature annealing condition. Moreover, the improvement of order features through radial distribution functions was pointed out during several heating-cooling processes. The formation of small clusters of few planar molecules can be easily observed by means of visual inspection. The effect of simple flow conditions imposed on the system was also investigated. Imposed flows increase molecules mobility causing a raise of planar molecules and a greater uniform distribution of inter-molecular orientational order vector.