Biodegradable Films and Coatings from Polysaccharides

GARCÍA, M.A; PINOTTI, A; MARTINO, M; ZARITZKY, N

Biodegradable Films and Coatings

Sobral, P

Año: 2006;

Edible and biodegradable films can offer great potential to enhance food quality, safety and stability. Composite films can be formulated to combine the advantages of each component. Proteins and polysaccharides provide the supporting matrix and are good barriers to gases, while lipids provide a good barrier to water vapor. Polysaccharides form a supporting matrix of films and coatings, giving selective barrier properties to gases. Native or modified starches are a natural mixture of compatible polysaccharides; amylose proportion determine the properties of films. These characteristics, in addition to their low cost and high disponibility increase their potential applications. Besides, plasticizer and lipid addition allow to optimize barrier and mechanical properties of starch-based films and coatings. In the formulation and application of an active film or coating, deteriorative mechanisms that limit the shelf-life of the substrate must be considered. On the other hand, film performance can be evaluated by microstructural analysis,  transfer and mechanical properties and their relation with film composition.  Physical properties of composite films showed intermediate (solubility and mechanical properties) values compared to those of individual component films or did not differ significantly (WVP) reinforcing the idea of compatibility of CH and MC polymer. These combined biodegradable films with good water vapor barrier properties have the possibility to tailor mechanical and solubility properties, within a range, based on polymer ratio composition. CH imparts rigid characteristics to composite films (high elastic modulus and small elongation) while MC contributes with a higher elongation and lower elastic modulus, increasing solubility as well. Thus, MC-CH edible films can lead to many possible applications in food, pharmaceutical and cosmetic industry considering the natural origin of both polymers.   These combined biodegradable films with good water vapor barrier properties have the possibility to tailor mechanical and solubility properties, within a range, based on polymer ratio composition. CH imparts rigid characteristics to composite films (high elastic modulus and small elongation) while MC contributes with a higher elongation and lower elastic modulus, increasing solubility as well. Thus, MC-CH edible films can lead to many possible applications in food, pharmaceutical and cosmetic industry considering the natural origin of both polymers.