Mixture of aroma compounds: Determination of partition coefficients in complex semi-solid matrices

The phase ratio variation method was used to determine partition coefficients of a mixture of aroma compounds in a complex model of fruit preparations containing starch and pectin or carrageenans as texture agents. This method enables easy determination of the partition coefficient of volatile compounds in a gas/matrix system without requiring any calibration. The present results were fully consistent with published data obtained with other methods. The influence of temperature on volatility as well as the effect of the composition and of the texture of the matrix were investigated. Under equilibrium an effect of polysaccharides was found only with hexanal, limonene, diacetyl and linalool. These were apparently trapped inside the matrix. Measurements on simplified systems suggested that retention was not due to interactions between aroma compounds and the gelling polysaccharide but rather to trapping in the complex network or to a combined effect of starch and of the gelling polysaccharide.