Stabilization of Aroma Compounds through Sorption−Release by Packaging Polymers

Abstract

Plastic packaging materials are often associated to aroma losses and to a decrease of the organoleptic quality of foods. This work defines situations where, on the contrary, plastics play a regulating role on the concentration of reactive aroma compounds in foods. These systems can be described by a two step mechanism; first, aroma is sorbed in the polymer, while the fraction in solution degrades quickly; in a second step, as the concentration is close to zero in the solution, the polymer liberates progressively the sorbed aroma back to the food. A simple numerical model is proposed, describing competitive processes of aroma degradation in solution and sorption by a polymer in contact with a homogeneous aqueous food. The classical limonene/low density polyethylene (LDPE) system is studied experimentally for the validation of the model: in an acidic medium, limonene both degrades quickly and is sorbed quickly, with a large solubility in LDPE. To define which aroma packaging systems could also display this interesting behavior, all types of possible interactions, using thermodynamic and kinetic parameters describing most practical situations, are simulated. For that purpose, 35 values of reference diffusion coefficients and 35 partition coefficients of usual aroma compounds between polymers 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 partition coefficients (above 10), large diffusion coefficients (>10(-9) cm2 x s(-1)), and large degradation constants.

A method to determine volatile contaminants in polyethylene terephthalate (PET) packages by HDC-GC-FID and its application to post-consumer materials

“…It is worth mentioning that the majority of the contaminants identified in the samples analysed in the present study have already been identified in recycled PET by other authors (NERÍN et al, 2003;NIELSEN, 2005;NIELSEN;DAMANT;CASTLE, 1997;FRANZ;WELLE, 2002;REYNIER et al, 2004;KONKOL et al, 2003), confirming the suitability of the method proposed in this article.…”

“…The method was in-house validated according to the following criteria: linearity and linear range, sensitivity, selectivity, intra-assay and inter-assay precision, detection and quantification limits, and accuracy (LIN et al, 1997;RIBANI et al, 2004 Based on these results, a temperature of 155 °C was selected and the extraction time varied to evaluate the recovery levels of the model substances. Figure 3 shows the recovery profiles at 4 different times: 30, 60, 90, and 120 minutes.…”

“…The techniques for the extraction of the volatile compounds absorbed by the packaging material include the use of solvents, concentration of the extract, and subsequent determination by Gas Chromatography (GC) using a flame ionisation (FID) or Mass Spectrometry (MS) detector (LEBOSSÉ; DUCRUET; FEIGENBAUM, 1997;PAIK, 1992;REYNIER et al, 2004;FREIRE et al, 1998;KALJURAND;SMIT, 1994;NIELSEN, 2005). Currently, the most used extraction systems involve headspace analysis.…”

“…There are many variations to this analytical technique such as the direct analysis of the headspace, and static and dynamic concentration of the headspace using traps consisting of porous polymers, especially tenax (FRANZ;MAUER;WELLE, 2004;van WILLIGE et al, 2003;KALJURAND;SMIT, 1994;HAKKARAINEN;GRONING;ALBERTSSON, 2003;SOTO-VALDEZ;GRAMSHAW;VANDENGURG, 1997;NIELSEN, 2005;NONGONIERMA et al, 2006). Recent advances include automatic systems that allow the coupling of the headspace sampler to the gas chromatograph injector, known as the purge and trap injection system (LEBOSSÉ; DUCRUET; FEIGENBAUM, 1997;WEZL;LANKMAYR, 2002;REYNIER et al, 2004;VILLBERG;VEIJANEN;GUSTAFSSON, 1998;KALJURAND;SMIT, 1994). The solid phase micro-extraction system is a recent modification introduced for the analysis of matrixes such as packaging materials (ZHANG; PAWLISZYN, 1993;EZQUERRO;PONS;TENA, 2003;PAWLISZYN, 1997).…”

Contaminantes voláteis provenientes de embalagens plásticas: desenvolvimento e validação de métodos analíticos

“…6,[28][29][30][31][32][33] Alguns autores sugerem que o aumento da concentração de analitos pode ser obtido por destilação ou evaporação a vácuo. 20,28,34,35 Para materiais de embalagem, o uso de técnicas de extração de voláteis está associado a avaliações qualitativas e quantitativas dos processos de permeação, sorção e migração, envolvendo medidas de coeficientes de partição, constantes de difusão e determinação de curvas de sorção para substâncias permeantes.…”