Food matrices – determination of odorant partition coefficients and application of models for their prediction

Foods are complex multi-component systems which are composed of volatile and non-volatile substances. The flavour profile of a food is an important criterion for the selection of our foodstuffs. The main objective of this study was the clarification of the complex relationships of the flavour release as a function of the composition of the food matrix at molecular level. Therefore the influence of matrix effects onto the odorants partition coefficients in oil–water model systems and a custard sample were investigated. The studies included a series of lactones, ester and alcohols (γ- and δ-octalactone, γ- and δ-nonalactone, γ- and δ-decalactone, ethyl hexanoate, 3-methyl-1-butanol and 2-phenylethanol). The partition coefficients were determined using static headspace gas chromatography (SH-GC). The results indicated that the custard/air partition coefficients of selected odorants are located between the water/air- and miglyol/air partition coefficients. Furthermore the mass transfer rates of selected odorants were investigated in custard- and milk powder–water samples. The values of the mass transfer rate were found higher in milk powder/water systems than in custard model. Nevertheless the results indicated that the viscosity of the matrix did not significantly influence the values of mass transfer rate of selected flavour compounds.