Transfer of aroma compounds in water-lipid systems: binding tendency of beta-lactoglobulin

Interactions of volatile aroma compounds with protein in aqueous solutions, especially whey proteins, have received significant attention in recent years. This work attempts to improve our understanding of the mass transfer in multiphasic systems, such as emulsions at the lipid-water interface, and to reveal the role of beta-lactoglobulin in the release rate of solutes. For this purpose the rotating diffusion cell has been used. From a practical point of view it enables evaluation of the transfer through the aqueous phase, through the oil and the interfacial transfer. The effect of beta-lactoglobulin, medium pH, and solute concentration has been investigated. Benzaldehyde and 2-nonanone have been studied, and miglyol has been chosen as an oil phase. It has been demonstrated that mass transfer has a rate-limiting step, which depends on physicochemical parameters such as hydrophobicity of the volatile, diffusion and partition coefficients, and rheological properties of the aqueous phase.