DROPLET SIZE AND EMULSIFIER TYPE AFFECT CRYSTALLIZATION AND MELTING OF HYDROCARBON-IN-WATER EMULSIONS

Differential scanning calorimetry was used to monitor crystallization and melting of 20 wt% n-hexadecane oil-in-water emulsions. The temperature at which droplet crystallization occurred depended on type of emulsifier used to stabilize the droplets: sodium caseinate, whey protein isolate, Tween 20, 40, 60 and 80 or sodium dodecyl sulfate. Emulsifiers with hydrocarbon tails close in structure to n-hexadecane promoted crystallization at higher temperatures, which suggested that emulsifier molecules at the interface acted as nucleation sites for oil. Smaller droplets crystallized at a slower rate than larger droplets. Droplet size and emulsifier type had no appreciable effect on melting behavior of the droplets.