The effectiveness of an antioxidant-impregnated film to retard autoxidation of a packaged model product containing linoleic acid, via an evaporation/sorption mechanism, was evaluated as a function of storage time and temperature. The rate of loss of antioxidant from the package film structure was described by a first-order expression. The first-order rate constants were dependent on the initial concentration of antioxidant in the film. The rate of loss of 3,5-di-tert-butyl-4-hydroxytoluene (BHT) from the package film structure was found to be much higher than the rate of loss of α-tocopherol at both storage conditions (23 and 45 • C, 50% relative humidity) studied. A freeze-dried model food product system was developed as the source for the autoxidation of linoleic acid in storage stability studies. The storage stability of this model food system packaged with antioxidant-impregnated film pouches was evaluated. Hexanal as an index of oxidation from the model product system was collected by a dynamic purge and trap system and quantified by a gas chromatography/mass spectrometry procedure. The BHT-impregnated laminate pouch showed a notable effectiveness in retarding lipid oxidation of the model product at 45 • C as a function of storage time. The control (non-antioxidant) and α-tocopherol-impregnated laminate pouch structures showed no effect on retarding lipid oxidation of the model product during storage at 45 • C.

No abstract

A simulation model computer program, which accounts for not only the diffusion process inside the polymer but also partitioning of the contaminant between the polymer and the contacting phase, was developed based on a numerical treatment, the finite element method, to quantify migration through multilayer structures. The accuracy of the model in predicting migration was demonstrated successfully by comparing simulated results to experimental data. For this study, three-layer coextruded high density polyethylene (HDPE) film samples, having a symmetrical structure with a contaminated core layer and virgin outer layers as the functional barriers, were fabricated with varying thickness of the outer layers and with a known amount of selected contaminant simulant, 3,5-di-t-butyl-4-hydroxytoluene (BHT), in the core layer. Migration of the contaminant simulant from the core layer to the liquid food simulants was determined experimentally as a function of the thickness of the outer layer at different temperatures. The computer program, developed as a total solution package for migration problems, can be applied not only to multilayer structures made with the same type of plastics but also to structures with different plastics, e.g. PP/PE/PP. This work might provide the potential for wider use of recycled plastic, especially polyolefins, which have lower barrier properties, in food packaging, and simplification of the task of convincing the FDA that adequate safety guarantees have been provided.

The rate of loss of the antioxidant 2‐tertiary‐butyl‐4‐methoxy phenol (BHA) from high‐density polyethylene (HDPE) was determined using high pressure liquid chromatography (HPLC). The rate of loss was found to follow a first‐order expression. Almost all of the antioxidant was lost (>95 percent) within 1 day at 50°C, within 3 days at 40°C, and within 7 days at 30°C. The controlling parameter for mass transfer of the antioxidant was found to be volatilization rather than diffusion.