wherein: X is the amount of water
and Xm represents the moisturecontent of the monolayer,
both expressed in dry basis [g/100 g];
aw is the water activity [];
C is an energetic constant related to first layer net heat of sorption,
also called as Guggenheim constant;
and K is a parameter that takes into account the difference of chemical potential between the multilayer and bulk water in the food(Fasina, 2006).