Process Optimization, Fabrication, and Characterization of a Starch-Based Biodegradable Film Derived from an Underutilized Crop

Abstract

We developed an affordable, environmentally friendly, and biodegradable film as an alternative to traditional nonbiodegradable plastics using the tuber starch of the Colocasia esculenta (CE) plant. Starch was yielded to a 21.56% extent, and it contained 31% amylose, with minimal levels of protein and lipids and an ash residue of 2.6 ± 0.01%, attributed to essential minerals. To optimize the fabrication process, we employed response surface methodology (RSM) in conjunction with a hybrid statistical model of particle swarm optimization (PSO) and an artificial neural network (ANN). The process variables included CE starch, carboxymethylcellulose, and glycerol, while the responses measured were the water vapor transmission rate (WVTR), tensile strength (TS), and moisture content (MC). FTIR data unveiled the secondary structure of starch in both the original starch and film, specifically related to the skeletal models of glycosidic linkage pyranose rings. SEM imaging displayed a uniform microstructure without indicating phase separation among its components. The water contact angle of the film was greater than that of CE starch, with values of 69° and 51°, respectively. The developed film demonstrated biodegradability, with 32% degradation occurring during seven days. It exhibited thermal stability up to 332 °C and had a low WVTR of 34 g mm m^–1 day^–1, a high TS of 11 Mpa, and a low MC of 0.65%. The estimated cost of production of the film at a laboratory scale was 1.56 USD per kg. Therefore, the CE starch-based biodegradable film is a sustainable and cost-effective alternative to current commercial films used in food packaging.