New Requirements of the Measurements of Permeation Through Plastic Bottles
and Closures
MBAA TQ vol. 42, no. 4, 2005, pp.
346-351 |
VIEW ARTICLE
Martin Orzinski, Ingrid Weber, and Jan Schneider. Research Institute for
Engineering and Packaging in the Beverage Industry, VLB Berlin, Seestrasse 13,
D-13353 Berlin, Germany.
Abstract
One of the main characteristics of beer flavor stability is the flavor
stability threshold. Next to the storage temperature/duration movement and the
light, oxygen has an important influence on beer quality. Packaging material
such as glass or metal are nearly inert against oxygen permeation. The chemical
properties of plastic materials allow gases to permeate along the partial
pressure gradient between the inside and the outside of the package. A new test
method to measure the permeation through plastic material is presented. This new
test method combines oxygen-free bottle filling with an aging process. Every
month during the aging process, the oxygen and carbon dioxide contents of 5 of
30 filled bottles are measured. This aging and oxygen-free bottling mimic the
filling, bottling, and aging process in praxis. Different plastic materials,
such at polyethylene terephthalate (PET) and polyethylene naphthalate (PEN)
bottles, and closures, such as crown corks, plastic caps, etc., were examined.
The results show that the oxygen uptake separated for the bottles and closures.
Furthermore, the influence of a scavenger on the permeation through the
different materials was tested. The results of the permeation of one- and
two-piece closures with or without a scavenger are presented. The oxygen uptake
and the reduction of carbon dioxide over a time period of 6 months were
observed.
Keywords: closure, oxygen barrier, permeation, plastic bottle, PET
bottle, quick test
S�ntesis
Una de las caracter�sticas principales de la estabilidad sensorial de cerveza
es el umbral de este flavor. Adem�s de la temperatura de almacenaje, movimiento
y luz, el ox�geno tiene una gran influencia sobre esa estabilidad. Si bien
vidrio y metal son pr�cticamente inertes contra la introducci�n de ox�geno, las
propiedades qu�micas de materiales pl�sticos permiten que gases se trasladan a
lo largo del gradiente de presi�n parcial entre las partes internas y externas
de un envase. Se presenta un nuevo m�todo para medir la permeabilidad a trav�s
del pl�stico, donde se combina un proceso de envejecimiento con un procedimiento
de envasado sin la introducci�n de ox�geno. Se mide mensualmente el contenido de
ox�geno y de gas carb�nico de cinco de 30 botellas envasadas. Se examinaron
diferentes materiales, tales como botellas de terefthalato de polietileno (PET)
y nafthalato de polietileno (PEN), y diferentes tipos de tapa (tapas corona,
tapas pl�sticas, etc.) Se pudo observar que el aumento de ox�geno fue diferente
para las botellas y las tapas. Tambi�n se examin� la influencia de un
�scavenger� sobre la permeabilidad a trav�s de los diferentes materiales. Se
presentan los resultados de la permeabilidad a trav�s de tapas de una y de dos
piezas con y sin �scavenger�. El aumento de ox�geno y la reducci�n del contenido
de gas carb�nico se observ� a lo largo de seis meses.
Palabras claves: cierres, barrera contra ox�geno, permeabilidad, botellas
pl�sticas, botellas PET, prueba r�pida
