| Abstract
| - Plastic packaging materials are often associated to aroma losses and to a decrease of the organolepticquality of foods. This work defines situations where, on the contrary, plastics play a regulating roleon the concentration of reactive aroma compounds in foods. These systems can be described by atwo step mechanism; first, aroma is sorbed in the polymer, while the fraction in solution degradesquickly; in a second step, as the concentration is close to zero in the solution, the polymer liberatesprogressively the sorbed aroma back to the food. A simple numerical model is proposed, describingcompetitive processes of aroma degradation in solution and sorption by a polymer in contact with ahomogeneous aqueous food. The classical limonene/low density polyethylene (LDPE) system isstudied experimentally for the validation of the model: in an acidic medium, limonene both degradesquickly and is sorbed quickly, with a large solubility in LDPE. To define which aroma packaging systemscould also display this interesting behavior, all types of possible interactions, using thermodynamicand kinetic parameters describing most practical situations, are simulated. For that purpose, 35 valuesof reference diffusion coefficients and 35 partition coefficients of usual aroma compounds betweenpolymers and water have been measured and combined with the few available data from literature.The situations where polymers regulate the aroma concentration in food correspond to large partitioncoefficients (above 10), large diffusion coefficients (>10-9 cm2 × s-1), and large degradation constants. Keywords: Aroma; degradation; polymer; packaging; diffusion; sorption
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