ABSTRACT
The intent of this chapter is to be a brief, focused outline of the dominant physical interaction in anhydrous fats and oils. Broadly speaking, physical interactions may be taken as comprising the ubiquitous (charge-†uctuation-induced) London van der Waals type interactions (Lifshitz, 1956; Landau and Lifshitz, 1968; Leckband and Israelachvili, 2001; Parsegian, 2005; Israelachvili, 2006), and “electrostatic” interactions-interactions between those moieties that carry electric charges on suf—ciently large (long) spatial (time) scales and that can be considered as “permanent” (Cevc and Marsh, 1987; McLaughlin, 1989; Cevc, 1990). The last named encompass electric multipole (e.g., dipole-dipole) interactions. Although the distance dependence of electric dipole-dipole interactions can be similar to van der Waals interactions, the origins are different. Hydrogen bonding is a third, weaker, Coulombic effect, which is speci—c to certain proton-containing moieties and is short-range (<0.3 nm) and directional (Israelachvili, 2006). In nonquantum molecular dynamics, hydrogen bonding is treated as a combination of van der Waals forces together with attractive electrostatic interactions. Although it might be thought that fats and oils do not involve electrostatics, the presence of three carbonyl atomic dipoles per triglycerol together with the possibilities of hydrogen bonding in the case of all glycerols implies that electrostatic interactions should not be ignored.
