Release of Flavor Compounds from Micelles and O/W Emulsions

Flavor-holding capacities of three surfactants, polyglycerol monolaurate (PGML), sodium dodecyl sulfate, and ovalbumin, were investigated using ethyl acetate, 2-phenylethanol, and geraniol as model flavor compounds. Solid-phase microextraction method was used to determine their concentrations in a gas phase equilibrated with a solution containing the surfactant and flavor compounds. The flavor compounds increasingly dissolved in the solution at the surfactant concentration higher than its critical micelle concentration, except for 2-phenylethanol in an aqueous solution of ovalbumin. Dodecane and glyceryl trioctanoate were added to PGML solutions to understand the contribution of the hydrophobic moiety of the surfactant on the distribution of geraniol in micelles. The addition of dodecane had little effect on the distribution of geraniol. On the other hand, the addition of glyceryl trioctanoate was a little effective. These results suggested that the differences in the flavor holding property of the surfactants are due to the solubilization of these compounds in the amphiphilic region of the surfactant micelles, rather than the hydrophobic region of the surfactants. Solubilization in the ovalbumin solution seemed to be a more complicated phenomenon compared with those in other two surfactants.