Interactions between beta-lactoglobulin and flavour compounds of differentchemical classes. Impact of the protein on the odour perception of vanillin and eugenol

Interactions between beta-lactoglobulin and flavour compounds were analysed by instrumental and sensory studies. Affinity chromatography was used to d etermine binding constants of flavour substances belonging to different che mical classes. A systematic study on esters, pyrazines and phenolic compoun ds revealed that the increase in the hydrophobic chain length increases the affinity for the protein. Concerning the 4 diastereoisomers of 3-oxo-p-men thane-8-thiol, only the cis-trans isomery led to different binding constant s. In general, binding constants increased with increasing log P values, ex cept for the terpenic compounds studied, for which another explanation has to be found, taking into account the geometry of the molecule. Sensory anal yses applying a matching test showed that the addition of beta-lactoglobuli n had no effect on the odour perception of vanillin, but brought about a si gnificant decrease in the odour perception of eugenol.