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Preparation, characterization and performance evaluation of 'enset' starch bio-plastic and its potential application for food packaging.

Bune Erre, Temesgen D Desissa

‘Enset’, (‘enset’e Ventricosum, Family Musaceae), is an indigenous starchy vegetable tree native to southern Ethiopia. In this work, we investigated the possibility to use starch extracted from ‘enset’ for bio-plastic production and its potential use for food packaging. The water extraction method was used to extract the starch from the ‘enset’ using sodium metabisulfite as a solvent. The average moisture content, ash content, crude protein and yield of extracted starch were investigated with the corresponding value of 16.82%, 0.031%, 0.27%, and 82.87%, respectively. Then, the bioplastic film of the starch was produced by a solution casting method. Expert design RSM and ANOVA analysis were used to determine the optimum process parameters combination to find the highest yield of bio-plastic formation. Accordingly, glycerol content of 7.48% was obtained at a reaction temperature of 130°C and a drying time of 1654.7 min. The predicted optimum bio-plastic yield was around 80%. Bio-plastic with 10% of glycerol was more sensitive to moisture absorption. The obtained water vapor transmission rate (WVTR) was about 12.6 g/m2•d, 22.353 g/m2•d and 35.82 g/m2•d at a different relative humidity (RH) of 25%RH, 40%RH, and 60% RH, respectively. The range of the glass transition temperature (Tg), crystallization temperature (Tc) and melting temperature (Tm) of bio-plastic sample was obtained from a differential scanning calorimetry (DSC), with the corresponding values of 50°C – 100°C, 200°C – 230°C and 275°C – 340°C, respectively. The average tensile strength of the bioplastic was about 49.4 MPa. As the thickness of the bio-plastic film increases both the white index and the light transmittance wavelength increased. Application test study on the packaging of a fresh cut banana indicated that the obtained bio-plastic from ‘enset’ starch can be used for alternative food packaging industries.