Chapter 7 - Modeling Interactions in Edible Fats

Abstract

This chapter is concerned with the physical interactions, modelling techniques and computer simulation methods to study edible oils. It begins with van der Waals interactions and Lifshitz theory of atomic fluctuations to calculate the Hamaker coefficient, followed by the Lennard Jones 6-12 potential and a description of the Coupled Dipole method. A second section on electrostatics involves pointing out that triacylglycerol molecules possess partial charges and electric dipoles in their glycerol cores and that, in solid fats, such interactions are long range. This section also describes Poisson’s equation, boundary conditions and the method of image charges. Temperature effects come in through the Poisson-Boltzmann equation and its linearization. Finally the use of the Ewald method to handle long-range electrostatics is described. A third section on computer simulation describes coarse-grained approaches as well as the Monte Carlo technique and atomic scale molecular dynamics. This is followed by applications to crystalline nanoplatelet aggregation and oils in confined nanospaces. A fourth section deals with Dissipative Particle Dynamics and its application. Finally the use of structure functions, which are related to data from X-ray and neutron scattering, is described and applied.