Copyright © 2018 John Wiley & Sons, Ltd. Edible and biodegradable films are made of renewable resources, offer an alternative to synthetic plastics for packaging, and, unlike these, can be placed between phases in direct contact with food. Although there are different sources, such as lipids and carbohydrates, proteins are popular due to their abundance and their nutritional qualities. Protein for film elaboration can be extracted from cereals (gluten, prolamins), milk (casein, whey), muscle (myofibrillar), and the connective tissue (gelatin) of marine or terrain species. Requirements may vary depending on their future application; therefore, it cannot be said that 1 source or the other is better, because film properties will also differ due to their method of obtention. Therefore, it is necessary to know what kind of film is needed in order to choose the most suitable one.