Characterization of Starch and Composite Edible films and Coatings

GARCIA M. A. ; PINOTTI A. ; MARTINO M. ; ZARITZKY N

Edible films and Coatings for food Applications

Springer

Lugar: New York- London; Año: 2009; p. 169 - 209

Starch-based and composite edible films and coatings can enhance food quality,safety and stability. They can control mass transfer between components within a product, as well as between the product and the environment. They can improve the performance of the product through the addition of antioxidants, antimicrobial agents, and other food additives. The unique advantages of edible films and coatings can lead to the development of new products, such as individual packaging for particular foods, carriers for various food additives, and nutrient supplements.Film materials and their properties have been reviewed extensively in this book and previously.Composite films can be formulated to combine the advantages of each component. Biopolymers, such as proteins and polysaccharides, provide the supporting matrix for most composite films, and generally offer good barrier properties to gases, with hydrocolloid components providing a selective barrier to oxygen and carbon dioxide  Lipids provide a good barrier to water vapour, while plasticizers are necessary to enhance flexibility and to improve the film’s mechanical properties. Composition, microstructure and physical properties of biopolymeric films determine their possible applications. Controlling the film formulation allows tailoring of the mechanical and barrier properties of these materials, improving the efficiency of preservation for packaged foods. The study of film microstructure and interactions between film components provides insight into both the fundamental aspects of material science and the practical technologies for possible applications. Most of the methods used in the characterization of films in the solid state are based on the detection of structural and thermodynamic properties involving the crystalline amorphous structure. X-ray diffraction is probably the most important technique for observing the structural properties of crystalline solid materials, polymers, and undoubtedly food materials  . Thermodynamic changes can be evaluated by several calorimetric techniques and by thermomechanical analysis .The knowledge of thermodynamic state, molecular mobility and phase transitions are important, since they affect film barrier properties, which define the performance of films under conditions of common use and abuse. The objectives of this chapter are to describe: (a) the properties of different starch and composite films and their relation to their functionality, with special emphasis on film formulations based on starch, chitosan and methylcellulose; (b) the common methods of characterizing composite films and coatings and (c) the applications of these biomaterials.