The Effect of Adding Glycerol as a Plasticizer on Biodegradable Film Combination of Glucomannan from Porang Tubers (Amorphophallus oncophyllus) and Sodium Alginate

Abstract

Glucomannan is a polysaccharide of the hemicellulose type derived from porang tubers. Alginate has a colloidal structure that has the potential to form a biopolymer film component. Biodegradable films from porang flour have stiff and brittle properties so glycerol is used as a plasticizer. The purpose of this study was to determine the effect of adding glycerol in the formulation of biodegradable films containing glucomannan and sodium alginate. This research design is an experimental study. The material in this study was porang flour which was extracted in stages using 50 and 80% ethanol solvents. The biodegradable film formulation contains 2.5 grams of glucomannan, 2.5 grams of sodium alginate, 2 mL of 30% glycerol and 100 mL of distilled water. As a comparison, a biodegradable film formulation without glycerol was applied. Evaluation of the biodegradable film included organoleptic tests, swelling degree, biodegradation and FTIR. Data analysis was carried out using One Sample T-Test at a 95% confidence level. The evaluation results of biodegradable films showed that biodegradable films without glycerol were round with brownish color, brittle, stiff, tend to tear and less elastic, swelling degree of 39.98±0.091, thickness of 0.21±0.008 mm, and degraded for 21±1 days, while the addition of glycerol produced biodegradable films that were not stiff, torn and quite elastic, swelling degree of 30.41±0.079, thickness of 0.22±0.010 mm and degraded for 14±1 days. The results of data analysis using One Sample T-Test produced a p value > 0.05 in the thickness and swelling degree tests, while the biodegradation test produced a p value <0.05 at a 95% confidence level. This study concluded that the addition of 30% glycerol affected the biodegradation time of biodegradable films containing glucomannan and sodium alginate.