RESUMEN
Little is known about the barrier properties of polymer films during high pressure processing of prepackaged foods. In order to learn more about this, we examined the influence of high hydrostatic pressure on the permeation of raspberry ketone (dissolved in ethanol/water) through polyamide-6 films at temperatures between 20 and 60°C. Permeation was lowered by increasing pressure at all temperatures. At 23°C, the increasing pressure sequence 0.1, 50, 100, 150, and 200 MPa correlated with the decreasing permeation coefficients P/(10(9) cm² s-1) of 6.2, 3.8, 3.0, 2.2, and 1.6. Analysis of the permeation kinetics indicated that this effect was due to a reduced diffusion coefficient. Pressure and temperature acted antagonistically to each other. The decrease in permeation at 200 MPa was compensated for by a temperature increase of 20°C. After release of pressure, the former permeation coefficients were recovered, which suggests that this `pressure effect' is reversible. Taken together, our data revealed no detrimental effects of high hydrostatic pressure on the barrier properties of polymer films.
Asunto(s)
Butanonas/farmacocinética , Caprolactama/análogos & derivados , Embalaje de Alimentos/instrumentación , Presión Hidrostática , Polímeros , Calor , PermeabilidadRESUMEN
In a previous study Birke and Sims (1986) identified the 5.07 (10 y) Semmes-Weinstein monofilament, as the most useful tool, in measuring protective sensation in the sole of the foot of leprosy patients. This study has demonstrated that the standard 6 Nylon being used in Karigiri, is as good as the monofilament, in assessing protective sensation in leprosy patients. However there is a need for standardising procedures for measuring sensory loss in leprosy patients.