Resumo (PT):
Abstract (EN):
In this paper a mathematical model for prediction of moisture gain over storage time for
binary mixtures of moisture sensitive products was developed, which considered both the moisture
transfer through the polymeric film to the headspace and from the headspace to the product.
Moisture content within the product was assumed to be uniform for a given time and to relate to
the headspace humidity by the GAB sorption isotherm. The transient period of these experiments
was used to estimate the mass transfer coefficients. The model was validated by monitoring the
moisture take up by breakfast cereal and chocolate powder mixture in different materials, oriented
polypropylene (OPP) and low density polythelene (LDPE), during storage at 25ºC and 75% relative
humidity (RH). The model showed that for mixes some bias was clear, particularly for the cereal,
probably owing to interactions between the products. If the resistance of the product to moisture
uptake were not taken into consideration, the model would over-predict the experimental results by
up to 20%.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
6