Influence of extrusión parameters on thermal and mechanical properties of starch based films

PAULA GONZÁLEZ SELIGRA; OSWALDO OCHOA YEPES; LUCAS GUZ; LUCÍA FAMÁ; SILVIA GOYANES

Simposio; Frontiers in Physical Science; 2016

The use of edible films in the food industry has been constantly increasing, and starch-based films play a key role in this application, as starch is cheaper and more readily available worldwide than other natural resources. In its native form, starch is not processable as a thermoplastic since its melting temperature is higher than its degradation temperature, so it is necessary to add plasticizers, heat and/or mechanical work to induce the starch gelatinization process and produce a thermoplastic material. Thermal extrusion is one of the most widely used techniques to process starch-based polymers. During extrusion process starch granules are subjected to high pressure, heat and mechanical shearing forces in a relatively low moisture environment. Cassava starch based films were developed by the extrusion process using a laboratory twin-screw extruder. Glycerol and water were used as plasticizers. Different temperature profiles were evaluated with temperatures between 80°C and 140°C and the influence of screw speed was studied for a range from 25 to 120 rpm. Effects of extrusion parameters were investigated through the determination of thermal and mechanical properties of the starch films.