Edible films and coatings from animal origin proteins

This chapter focuses on the animal-origin proteins that exhibit excellent oxygen, carbon dioxide, and lipid barrier properties, particularly at low relative humidity. Edible films based on proteins were found to possess satisfactory mechanical properties. However, their predominantly hydrophilic character results in poor water-barrier characteristics. The increase of cohesion between protein polypeptide chains was thought to be effective for the improvement of the barrier properties of the films. Milk proteins, such as whey and casein proteins, were extensively studied due to their excellent nutritional value and their numerous functional properties, which are important for the formation of edible films. Caseinates can easily form films from aqueous solutions due to their random coil nature and their ability to form extensive intermolecular hydrogen, electrostatic, and hydrophobic bonds, resulting in an increase in the interchain cohesion. Moreover, edible films based on milk proteins were reported to be flavorless, tasteless, and flexible, and depending on the formulation, they varied from transparent to translucent. Whey and caseins are the main milk protein fractions. Caseins represent 80% of the total composition of milk proteins, with a mean concentration of 3% in milk.