FILMS BASED ON STARCHES Chapter 6

OLIVIA LOPEZ ; MARIA ALEJANDRA GARCIA; NOEMI ZARITZKY

Functional Polymers in Food Science: From Technology to Biology Volume 1 . Food Packaging

Editorial Wiley. Scrivener Publishing

Año: 2014; p. 147 - 209

The film-forming ability of different native and modified starches by casting method is discussed in this chapter. Likewise, rheological properties of filmogenic suspensions are described. The mechanical and barrier properties of films, as well as microstructural characterization of these biomaterials are also discussed since they determine their performance and applications, mainly in food preservation.Characterization of films was carried out using different complementary techniques such as infrared spectroscopy (FTIR), light microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Also, the plasticizer effect (glycerol and sorbitol) on films properties was analyzed.Even though film-forming capacity of different chemically modified corn starches was evaluated, this chapter only discusses the results concerning acetylated corn starch films. This selection was reliant on the lowest water vapor permeability of films based on this modified derivative. Addition of specific additives to formulation modifies films functionality transforming them in active films. Thus, in this chapter results concerning starch films with potassium sorbate are presented. Furthermore, antimicrobial agent diffusion from starch matrices is also discussed in order to demonstrate the effectiveness of these active films. With the purpose to develop biodegradable packages, heat sealing capacity of native and acetylated corn starch based films was studied. Film composition effect and presence of plasticizer on the type of heat sealing failure and its resistance isalso discussed.Thermoplastic starch (TPS) is a biodegradable material which can easily be adapted to different processes employing standard equipment used for syntheticpolymers, such as extrusion, blowing, injection and compression molding. Thus, development of biodegradable films from TPS by extrusion and blowing methods is discussed. The relevance of this study lies essentially in the demonstration of the possibility to develop biodegradable films based on TPS employing industrial methods