Fat crystal networks – structure and properties

When triglycerides are cooled from the melt to a temperature below their melting point, they undergo a liquid-solid transformation to form primary crystals with characteristic polymorphism. These crystals associate, or grow into each other, to form increasingly larger aggregates, which further interact, resulting in a continuous three-dimensional network. The macroscopic properties of a fat crystal network are affected by all these levels of structure, however, most directly by the level of structure closest to the macroscopic world. Most of the research in this area has been directed towards establishing a link between molecular structure and phase behavior, crystal habit, in particular crystal polymorphism, and the macroscopic properties of fats. Not including all levels of structure in the analysis is undoubtedly a major reason why these attempts have only been partially successful. In order to truly understand, and eventually predict, the macroscopic properties of fat-containing products, it is necessary to characterize and define the different levels of structure present in the material and their respective relationship to a macroscopic property. A macroscopic property is not always simply and directly related to molecular structure.