Biodegradable film based on taro starch with variations of duck bone gelatin concentration: Physical and barrier properties

Abstract

Introduction. This study aims to improve the physical properties of biodegradable films based on taro starch added with duck bone gelatin and glycerol as a plasticizer by using the solution casting method. Materials and methods. A non-factorial completely randomized design (CRD) with ANOVA was used, followed by the DUNCAN test to determine the effect of different treatments. Various concentrations of duck bone gelatin were used, including 0, 5, 15, 25 and 35% of the total weight of solids (taro starch and duck bone gelatin). The functional groups of biodegradable films were analyzed using Fourier Transport Infrared (FTIR). The morphological structure of the product was studied using Scanning Electron Microscope (SEM). Results and discussion. The parameters observed included the water vapor transmission rate test, which resulted in a value of 0.465 – 0.529 g/m2·hour. The highest water vapor transmission rate was at a concentration of 35% duck bone gelatin of 0.529 g/m2·hour. The factor that affects the value of the water vapor transmission rate is the chemical nature of the material polymer. Water absorption was 85.17–40.47%, and the highest water absorption was at a concentration of 0% duck bone gelatin. The percentage of water absorption is used to assess the value of the water resistance of the resulting film. Water solubility was 31.08–64.60%. The highest water solubility value was at a concentration of 35% duck bone gelatin of 64.60% because the addition of duck bone gelatin can reduce the intermolecular forces of the film and increase water activity so that free water molecules can occupy the matrix in the film. The FTIR spectrum for biodegradable film products showed a peak wavenumber at 3600–3000 cm-1, indicating the presence of N-H and OH groups. The presence of N-H and O-H groups in biodegradable films can help the degradation process because they have hydrophilic properties that enable water molecules to access and enter the film matrix. The results of SEM analysis showed that the taro starch film with the addition of duck bone gelatin produced a homogeneous and flexible biodegradable film with compact structure. Conclusions. The addition of duck bone gelatin had an insignificant effect on the water vapor transmission rate but a very significant effect on water solubility and a significant effect on water absorption.