Dialysis of flavour compounds: yields of extraction on model solutions

The extraction of 58 flavour compounds by Nafion membrane dialysis was studied using a model solution. Reproducibility and yield of the method were investigated. The coefficient of variation of the extraction yield was less than 15% for 48 of the 58 compounds tested. When the number of carbon atoms increased, the extraction yield fell to zero for compounds with more than ten carbon atoms. Flavour compounds with a cyclic structure showed a better diffusion rate through the membrane than other compounds with the same number of carbon atoms. The extraction yield seems to be correlated mainly to the hydrophobicity of the molecule. The use of the method for quantitative analysis was studied. Extraction rate can be considered as constant regardless of the quantity of compounds. The separation of flavour compounds from lipids was studied by this method. A better extraction yield with lipids was observed for eight compounds, for all other molecules no significant difference could be observed. The oil does not diffuse through the dialysis membrane