Under the saturated humidity conditions, the water vapour
flux
from the package headspace to storage environment is dominated
by the limiting step of the
film resistance to transport. The water
vapour permeability of the polypropylene
film used for control and
humidity-regulating tray was the same but still the experimental
data showed the difference in the amount of water transmitted
over the
film. Control-PP tray transmitted 1.3 g of water vapour into
the storage environment (85% RH); whereas the humidityregulating
tray transmitted significantly lower amount of water
vapour (0.8 g). This was due to the lower RH observed inside the
humidity-regulating tray (93% RH), therefore, lower driving force
for water vapour than the control tray (100% RH).