Aroma compounds of oxidised sunflower oil and its oil-in-water emulsion : volatility and release under mouth conditions

The influence of medium composition on the release and volatility (vapour/liquid partitioning) of volatile lipid oxidation products was studied in order to explain the differences in composition of volatiles released from oxidised sunflower oil and its 40% oil-in-water emulsion in a model mouth system. Volatile compounds were analysed by gas chromatography combined with flame ionisation detection and mass spectrometry. Larger amounts of volatiles, formed during oxidation, were released from the emulsion than from the bulk oil. Differences in release influenced the results as well as the partitioning, but showed contrary effects. Added reference compounds were released in larger quantities from the oil than from the emulsion in the model mouth, and higher vapour/liquid partitioning values were obtained for the emulsion in comparison with the oil. In addition, water and saliva components influenced the release of reference compounds in the model mouth and the partitioning, giving different results for the oil and the emulsion. In conclusion, differences in the release of volatile compounds due to medium composition influenced the composition of the volatile lipid oxidation products of sunflower oil and its emulsion, as well as the lipid oxidation rate.