Equilibrium sorption levels at 23°C were determined individually for two citrus flavor components (d-limonene and 1-carvone) into ground and unground polypropylene films of different crystallinities. Sorption levels at equilibrium were also determined for a mixture of the two flavor compounds. Aqueous solutions of the flavor compounds (200 ppm carvone and 1000 ppm limonene) were employed. Concentrations of flavors remaining in solution before and after exposure were measured by high performance liquid chromatography (HPLC). Results indicated flavor compound polarity, polymer crystallinity and the presence of other flavor compounds in a mixture influenced sorption behavior.

The thermal decomposition of polyethylene terephthalale has been examined by healing isothermally in a high‐mass reaction chamber and collecting the evolved acetaldehyde on a GC column for quantization. Kinetics were determined at lime intervals up to 1 h for temperatures 225°C, 240°C, 250°C, 260°C, 265°C, 270°C, 280°C, and 300°C. The rate of acetaldehyde evolution was found to be directly proportional to time of reaction at each temperature, thus fitting a zero‐order reaction. The Arrhenius plot of the data yielded a straight line above the melting point with a slope different from the straight line for reaction rates below the melting point. The change in slopes occurred around the crystalline melting point. The following thermodynamic values were found above and below the melting point, respectively: EA, 37.5 and 8.2 kcal/mol; ΔSA, + 1.5 and −54 e.u.; A, 0.68 × 1014 and 0.43 × 102 sec−1. Possible mechanistic implications are discussed.

Two corn meal extrudates with initial moisture contents of 22% and 31% W.B. were partially dried to moisture contents from 7% to 31% W.B. and stored in hermetically sealed containers to allow redistribution of the water. Compressive strength, compressive relaxation and instrumental texture profile analyses (fracturability, cohesiveness, springiness, gumminess and chewiness) were measured. Compressive strength increased with decrease in moisture content from 31‐15%, reached a maximum between 15‐10% and then decreased below 10%. Stiffness showed a similar relationship, with the maximum occurring between 10‐6%. Relaxation modulus increased with decrease in moisture content over the range studied. Relaxation time was a minimum at 15% moisture content. Fracturability had a similar relationship to moisture content as that of compressive strength. The textural behavior was ductile and chewy at moisture contents above 15% but became crisp or crunchy and collapsed with brittle fractures at lower moisture contents. Both compressive properties and texture profile parameters of the corn meal extrudates changed considerably with changes in moisture content.

Mixtures of seven characteristic flavor solutes commonly found in orange juice were studied for their interaction with low-density polyethylene (LDPE) from aqueous solutions at 20 "C. Precautions were taken t o avoid thermal and chemical degradation of the flavor solutes and degradation components were not found by HPLC analysis. Hydrocarbon monoterpenes showed 3 0 4 0 % sorption by the LDPE over a 25-day period. Oxygenated monoterpenes showed ca. 10% sorption in the same time period. Further study of one of the hydrocarbon terpenes (d-limonene) showed both adsorption (surface attraction) and absorption (matrix dissolution), while its analogous oxygenated terpene (Ccarvone) displayed predominantly adsorption. These findings are useful for deciding proper compensations for changes in flavor profiles in packaged orange juices in contact with LDPE. They also illustrate the importance of learning the nature of polymer-flavour interactions between foods and packaging materials.

Growth of Aspergillus flavus and Penicillium notatum was inhibited by a fungicide coupled to a packagingjfilm. A chemical method was employed to attach a fungicide containing amino groups to an ionomeric packaging $film containing pendent carboxyl groups. Dicyclohexylcarbodiimide was used as the coupling agent and dimethylaminopyridine as the catalyst for the reaction. Infra-red spectroscopy, weight gain and elemental analysis were used to demonstrate that the fungicide was coupled to thejlm.