Influence of the packaging material and the nature of the packed goods on the loss of volatile organic compounds - permeation of aroma components

Permeation of volatile compounds can alter the composition of aroma substances and decrease the quality of food with distinct aroma profiles. Diffusion, solubility and permeation constants of some flavouring compounds are measured by two simple methods (sorption/desorption method for polymer sheets; permeation method for polymer pouches). It is shown how diffusion, solubility and permeation depend on the nature of the polymer (LDPE, HDPE, PP-copolymer, PP-homopolymer, PVC). The influence of the matrix of liquid food on the permeation rate is demonstrated by some model systems. Partial pressures of the flavouring substances over different liquid systems are the main factors influencing the permeation by altering the partition constants (relative solubility constants). The relation of absolute and relative solubility and permeation constants and the usefullness of the application of relative values are discussed. Diffusion constants of linear alkane chains mark out the upper limiting values which cannot be crossed by aliphatic flavouring and aroma substances.