Chapter 6 Contribution of NMR Spectroscopy to Flavour Release and Perception

The control of flavouring of a food product as well as the flavour perception during consumption is a great challenge for improving food quality. However, the various ingredient composition and the different textural properties of foods can significantly affect the release of aroma compounds or sapid molecules. It is thus of major importance to determine physicochemical factors that govern diffusion and binding phenomena of these small solutes in food products. In this way, NMR spectroscopy is an efficient tool to characterize these mechanisms at a molecular scale. Diffusion rates of small solutes in aqueous, viscous and gel solutions can be extracted from relaxation or diffusion NMR experiments. PFG-NMR experiments are particularly valuable methods to investigate aroma compound self-diffusion and gel microstructure in a non-invasive way. A wide range of methods based on chemical shift, relaxation or diffusion rate changes also provide unique and direct information on binding events of aroma compounds with food macromolecules. Binding site localization, affinity constant and spatial conformation of complexes can be achieved using conventional 1D- and 2D-NMR spectroscopy.