ABSTRACT
Edible coatings and films have many desirable properties which have led to their use in the food industry. Mass transport phenomenon occurs due to the natural tendency of systems to reach equilibrium. Permeance measures the amount of permeant that crosses a film, which is determined per unit area, time and pressure difference, while the transmission rate measures the amount of permeant that crosses a film per unit area and time, under specific conditions. The biodegradable and edible films are totally or partially composed by hydrophilic polymers such as proteins or polysaccharides accompanied of polar plasticizer compounds. Moisture can be absorbed into hydrophilic polymers, due to the hydrogen bond interactions that are established with the water adsorbed from the environment. Another of the most common features usually present in edible films and coatings, and that also greatly complicates the mathematical modeling, is the high hydrophilicity of most polymeric materials that constitute them.
