Mathematical model of flavor release from liquids containing aroma-binding macromolecules

A mathematical model has been developed to describe flavor release from aqueous solutions containing flavor-binding polymers. First-order chemical kinetics is used to describe the reversible binding of the aroma and polymer, and the penetration theory of interfacial mass transfer is used to model flavor release across the gas-liquid interface. The model is used to predict the equilibrium partitioning properties and the rates of release of two volatiles, one hydrophilic (diacetyl) and the other hydrophobic (heptan-2-one), as a function of the binding constants and first-order rate constants. In general, the rates of release are shown to be more sensitive to changes in the binding constant than the rate constants. Increasing the flavor-binder interaction leads to decreased release rates and a lower final headspace aroma concentration. Nevertheless, the results suggest that in most situations the rate-limiting step for flavor release is not the chemical binding step but the transport of aroma across the liquid-gas interface.