ABSTRACT
This chapter reviews research on protein film-formation fundamentals and film properties. It relates properties of protein-based films to molecular and environmental factors. The chapter compares barrier and mechanical properties of protein-based films to each other, polysaccharide-based films, and synthetic films. It summarizes applications of protein films in food products, and makes conclusions as to the status of protein films and future directions. Edible films and coatings based on proteins, polysaccharides, and/or lipids have much potential for increasing food quality and reducing food-packaging requirements. Edible films can be formed by drying aqueous ethanol solutions of zein. Formation of films is believed to involve development of hydrophobic, hydrogen, and limited disulfide bonds between zein chains in the film matrix. Edible films and coatings can be formed from total milk protein or components of milk protein. Milk proteins are classified into two types: casein and whey protein.
