Release and Transport of Flavors In Vivo: Physicochemical, Physiological, and Perceptual Considerations.

For flavor perception to occur, the chemicals responsible for flavor perception must be released from the food matrix and transported to the flavor receptors in the mouth and nose. The overall process is governed by the properties of the flavor compounds, the nature of the food matrix and the physiological conditions of the mouth, nose and throat during consumption of the food. These factors combine to determine the concentrations and rate at which the flavor chemicals reach the receptors, thus creating the characteristic flavor profile of a food. Physicochemical factors like partitioning, interfacial mass transport and diffusion are the typical mechanisms governing flavor release. Although the theory behind these factors is well understood, applying them to the situation in-mouth during eating is difficult. This is because key parameters like surface area and flavor concentrations in the gas and liquid phases change rapidly with time as a result of the physiological processes occurring during eating. Furthermore, individuals vary in their rate of breathing, swallowing and salivation, which affects the transport of flavors from the saliva phase to receptors on the tongue and in the nose. This review covers all aspects of flavor release from food matrices and the subsequent delivery of flavor to the olfactory and gustatory receptors.