Aroma Release from Solid Droplet Emulsions: Effect of Lipid Type

Aroma compounds partition between the different phases of a food emulsion and the headspace but only those in the headspace are perceived. Phase transitions in the lipid droplets profoundly affect the position of the partitioning equilibria and hence headspace aroma concentration. The release of four volatile aroma compounds (ethyl butanoate, pentanoate, heptanoate and octanoate) from eicosane, hydrogenated palm fat or Salatrim^® emulsions stabilized with sodium caseinate were investigated as a function of fat crystallization, particle size and droplet concentration. For all compounds, the headspace aroma concentration in equilibrium with solid droplet emulsions was significantly higher than that in equilibrium with liquid droplet emulsions. The partitioning of volatile aroma compounds from emulsion does not depend on the type of liquid lipid, however, the interactions between solid lipid droplets and aroma compounds are significantly influenced by the nature of the crystalline fat. Notably, partitioning into the headspace was much lower for solid triglyceride droplet emulsions than for solid alkane emulsions. It was proposed that both residual liquid lipid in solid triglycerides and aroma co-crystallization with solid lipid could be responsible for higher aroma absorption by solid triglycerides.