Physico-Chemical Properties of Extruded Copolymer Film

Abstract

The aim of this study was to investigate the properties of copolymer films made from cassava starch and jellyfish gelatine with glycerol or sorbitol as a plasticizer. The concentrations of gelatine used were 1 and 3% (wt/vol). The prepared copolymer of cassava starch solution (5%) and gelatine solution (1:1 (vol/vol)) was mixed with glycerol or sorbitol (30%) prior to extrusion. The feeding rate of solution was 1 kg/h and the extruder screw speed was 30 rpm. The films were dried by an infared dryer. All extruded films had the thickness of 0.10–0.30 mm. At 1% jellyfish gelatine, the glycerol plasticized copolymer film yielded higher tensile strength, water vapor transmission rate, oxygen transmission rate and %solubility than the sorbitol plasticized film. As the concentration of jellyfish gelatine increased to 3%, the elongation of glycerol plasticized film increased approximately five times compared to two times for sorbitol plasticized films. Practical Applications Gelatine, a denatured form of collagen protein, can be derived from pig, beef or fisheries products such as fish, squid and jellyfish. The application of gelatine is widely used for food and biomedical aspect. The film copolymer of cassava starch and gelatine can be formed by a single screw extruder with glycerol or sorbitol as a plasticizer. The copolymer film with glycerol showed noticeable elongation property, which could be benefit for the development of edible film.