Degradation of low density polyethylene during extrusion. IV. Off‐flavor compounds in extruded films of stabilized LDPE

Abstract

This study was aimed at finding a correlation between the experienced off-flavor in packed foods and the presence of specific degradation products in LDPE packaging films. The possibility to trap degradation products by chemical reactions with scavengers, i.e., a zeolite additive or antioxidants, was investigated This would prevent degradation products from migrating to the polymer film surface and further into food in contact with the film. It was found that off-flavor noted in water packed in LDPE films depended on extrusion temperature and exposure time for the melt to oxygen, that is, the parameters that influence the contents of oxidation products that are able to migrate from the polymer film. It was also found that adsorption of oxidative degradation products in a zeolite additive or protection of LDPE by using antioxidants could prevent off-flavor in the packed product (water). However, the antioxidant should be selected with regard to extrusion temperature because thermal instability in the additive might jeopardize the intended effect. Multifunctional antioxidants seem to provide improved protection, the most effective one evaluated in this work being Irganox E201, i.e., vitamin E. Concentrations of oxidized degradation products are well correlated to the perceived off-flavor in the packed water. The highest correlation between off-flavor and oxidized components was found for ketones in the range of C 7 to C 9 and aldehydes in the range of C 6 to C 9 . © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: [583][584][585][586][587][588][589][590][591][592][593][594][595] 2005

Thermal and mechanical modification of LDPE in single‐screw extruder

“…As the drawback of such high‐temperature processing, however, some oxidized substances were found both in the smoke from extruded films3 and also in the films 4. The oxidized compounds lead to an “off‐flavor” that affects the taste of products in the food package 5, 6…”

The effects of selected aldehydes, ketones and carboxylic acids on off‐flavours in water

“…Based on the findings of previous studies, which shows that volatile compounds in extruded films create off‐flavours (Andersson et al. , 2005a,b), the following six compounds were selected for this study: two aldehydes hexanal 96%, octanal 99%; two ketones 2‐octanone 99+%, 5‐nonanone 98% and two organic acids hexanoic acid 97% and nonanoic acid 98%.…”

“…, 2005a,b), the following six compounds were selected for this study: two aldehydes hexanal 96%, octanal 99%; two ketones 2‐octanone 99+%, 5‐nonanone 98% and two organic acids hexanoic acid 97% and nonanoic acid 98%. These six compounds were recognized as the compounds that correlated most highly with the intensities of off‐flavours when different oxidized polythene films had been in contact with water (Andersson et al. , 2005a,b).…”

“…The degradation of polythene polymers in polymer processing and its potential introduction of off‐flavours into food has been investigated and reported in several papers (Holmström & Sörvik, 1970; Iring et al. , 1978; Hoff & Jacobsson, 1981; Storm van Leeuwen & Wullms, 1998; Villberg & Veijanen, 1998, 2001; Wiik & Helle, 2002; Andersson & Wesslén, 2003; Andersson et al. , 2005a,b).…”

“…, 2005b). Degradation compounds have been linked to perceived off‐flavours in water and this has been correlated with the extrusion conditions and the oxidized degradation products (Andersson et al. , 2005a,b).…”