Food Aroma Mass Transport in Metallocene Ethylene-Based Copolymers for Packaging Applications

Abstract

The permeation of five volatile organic compounds found in Iberian ham aroma (n-hexanal, n-hexanol, n-decane, ethyl caproate, and d-limonene) through films of ultra-low-density polyethylene (ULDPE) and two metallocene copolymers was evaluated at 23 °C. Values of the diffusion, permeability, and solubility coefficients were determined. The polymer films were characterized by differential scanning calorimetry, size exclusion chromatography, and oxygen permeability. Compared to ULDPE, the metallocene copolymers were lower in molecular weight, showed narrower molecular weight distributions, presented less crystallinity, and offered greater oxygen permeability. Solubility coefficient values were lower for compounds having higher polarity, and diffusion coefficients were higher for compounds of smaller molecular size. The permeability coefficients, which combine the effects of diffusion and sorption contributions, indicated that the films were more permeable to nonpolar small-size aromas. Overall, metallocene copolymers showed higher permeability values than ULDPE. Keywords: Metallocene polyethylene; aroma permeation; polarity; size

Experimental and theoretical investigation of packaged olive oil: Development of a quality indicator based on mathematical predictions

“…(iii) PVC: 3.2 · 10 À11 cm 2 /s at 15°C, 4.0 · 10 À11 cm 2 /s at 30°C and 5.1 · 10 À11 cm 2 /s at 40°C (Feigenbaum et al, 1991;Hernandez-Munoz et al, 1998). 5.…”

“…(ii) PET: 1.9 · 10 À11 cm 2 /s at 15°C, 3.6 · 10 À11 cm 2 /s at 30°C and 4.8 · 10 À11 cm 2 /s at 40°C (Feigenbaum et al, 1991;Hernandez-Munoz, Catala, Hernandez, & Gavara, 1998). (iii) PVC: 3.2 · 10 À11 cm 2 /s at 15°C, 4.0 · 10 À11 cm 2 /s at 30°C and 5.1 · 10 À11 cm 2 /s at 40°C (Feigenbaum et al, 1991;Hernandez-Munoz et al, 1998).…”

Effect of water on the oxygen barrier properties of poly(ethylene terephthalate) and polylactide films

“…If an error level of 5% is considered acceptable, the values obtained for these two constants are as follows: 0.42 Յ K 1 Յ 0.46 and 0.65 Յ K 2 Յ0.69. 35,38 The calculation of K 1 and K 2 permits the evaluation of whether isostatic tests have been carried out under the right conditions and also checks the diffusion mechanics that take place. In addition, from the transient flow rate profile, the half-time diffusion coefficient (D) can be estimated as follows:…”

Factors determining the transport coefficients of aroma compounds through polyethylene films

“…Low density polyethylene (LDPE) films, which have been extensively studied, absorb a wide variety of flavour compounds such as aldehydes, methyl ketones, methyl esters, and sulphur compounds (Arora et al, 1991;Letinski and Halek, 1992). Factors that influence sorption, include molecular size, polarity, solubility, and concentration of the aroma compounds along with the properties of polymers such as morphology, glass transition, crystallinity, and polarity (Dury-Brun et al, 2007;Hernandez-Muñoz et al, 1998;Nielsen et al, 1992b). Flavour sorption in rubbery polymer such as PE, can be several thousand times higher than sorption in glassy polymers such as PET, or polycarbonate (PC).…”

“…LDPE (low density polyethylene) and MDPE (medium density polyethylene) have a highly branched structure, are thermoplastic and partially crystalline, while HDPE (high density polyethylene) and LLDPE (linear low density polyethylene) are, respectively, a linear homopolymer strongly crystalline and a weakly crystalline linear copolymer having alkene as co-monomer. These varied structures can induce some differences in material properties such as density, mechanical and barrier properties (Hernandez-Muñoz et al, 1998.…”