Study of interactions between food phenolics and aromatic flavors using one- and two-dimensional H-1 NMR spectroscopy

Changes in flavor release and aroma characteristics in a medium including f ood phenolics may be attributed to an intermolecular interaction between fl avor compounds and phenolics. To investigate the interaction, one- and two- dimensional NMR studies have been carried out on the binding of two phenoli cs, gallic acid and naringin, with three aroma compounds, 2-methylpyrazine, vanillin, and ethyl benzoate. Evaluation of thermodynamic parameters and i ntermolecular nuclear Overhauser effects reveals that gallic acid can inter act more strongly with aromatic flavors than naringin. The supramolecular c omplexation is also dependent on the structural nature of the flavors, with 2-methylpyrazine and vanillin interacting more strongly than ethyl benzoat e. The interaction is principally pi-pi stacking between the galloyl ring a nd the aromatic ring of the aroma compounds, but secondary hydrogen-bonding effects help to stabilize the complex and enhance the specificity.