FILMS BASED ON STARCHES

OLIVIA LOPEZ, ; MARIA ALEJANDRA GARCIA ,; NOEMI ZARITZKY

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

John Wiley and Sons- Scrivener Publishing

Año: 2015; p. 147 - 197

 The film-forming ability of different native and modified starches by castingmethod is discussed in this chapter. Likewise, rheological properties of filmogenicsuspensions are described. The mechanical and barrier properties of films, as wellas microstructural characterization of these biomaterials are also discussed sincethey determine their performance and applications, mainly in food preservation.Characterization of films was carried out using different complementary techniquessuch as infrared spectroscopy (FTIR), light microscopy, scanning electronmicroscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, differentialscanning 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 cornstarches was evaluated, this chapter only discusses the results concerning acetylatedcorn starch films. This selection was reliant on the lowest water vapor permeabilityof films based on this modified derivative.Addition of specific additives to formulation modifies films functionality transformingthem in active films. Thus, in this chapter results concerning starch filmswith potassium sorbate are presented. Furthermore, antimicrobial agent diffusionfrom starch matrices is also discussed in order to demonstrate the effectiveness ofthese active films.With the purpose to develop biodegradable packages, heat sealing capacity ofnative and acetylated corn starch based films was studied. Film composition effectand 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 synthetic polymers, 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.