Fat crystallization – from simplicity to complexity

Fat crystallization is a complex process at the best of times. Today, much of our knowledge on single and mixed triglyceride crystallization comes from great minds such as Lutton (1940s-1960s), Larsson (1960s-1970s) and Sato (1990s-2000s). Much of their work focused on simple fats close to, or at, equilibrium.

The seminal work of van den Tempel in the 1960s brought to light the challenges associated with understanding fat crystallization at different length scales and under non-equilibrium conditions. Decades later in the 1990s, seminal work by Marangoni led to a shift towards complexity where synergy rather than additivity was exploited to understand the hierarchical organization of fat crystal networks.

The next frontier in this field is that of fat crystallization in complex, multi-component environments. Fat in foods is rarely present alone. Rather, it is often solidified in the presence of emulsifiers and/or dispersed particles. Emulsifiers are typically low molecular weight species added to fat to modify its crystallization kinetics from the melt or to lock in a specific polymorph. This is achieved through their direct interaction with triglycerides. In a different vein, dispersed particles (whether solid, liquid or gaseous) are typically micron-sized and predominantly affect fat crystallization by acting as new surfaces to promote surface nucleation, crystal growth and possibly polymorphic transitions. The crystallization control offered by both emulsifiers and dispersed particles can play a big role in the texture and rheology of fat-containing foods.

 
This presentation will present a brief historical overview of the effects of common emulsifiers and dispersed particles on fat crystallization followed by recent findings on their implicit and intriguing contributions to food structure design in fat-containing foods.