Cellulose as Coatings and Films Material

Coatings and edible films are used to protect food products and improve their quality and shelf life. There has been a great interest in production of edible films and coatings from biopolymers in recent years. The most widely used edible and biodegradable films are cellulose derivatives. 

As cited in Guilbert and Gontard, 2005 [3], agro-polymers that have been proposed to formulate edible films or coatings are numerous (Cuq et at, 1995 Guilbert and Cuq, 1998). Plant polysaccharides such as cellulose and derivatives are used in various forms (simple or composite materials, single-layer or multi-layer films). The formulation of bioplastic or edible films implies the use of at least one component able to form a matrix having sufficient cohesion and continuity. They are polymers, which under preparation conditions, have the property to form crystalline or amorphous continuous structures [3]. 

A few examples of applications of cellulose edible films or coatings are discussed below. They are used to increase product appearance or conservation (increasing shelf life). 

Edible coatings are thin layers of edible biopolymers applied on the surface of foods as protective coatings. One of the benefits of using cellulose esters in coating is the control of viscosity properties. 

In the film-forming mechanism (wet process), a wet gel should be converted into dry film in which the film-forming materials are dispersed in the solvents, followed by drying to remove the solvent and form a film structure. Therefore, there is a critical stage of a phase transition from a polymer-in-water (or other solvents) system to a water-in-polymer system. 

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