Nugraha Edhi Suyatma

Antimicrobial and Physical Properties of Chitosan Film as Affected by Solvent Types and Glycerol as Plasticizer

This study aims to evaluate the influence of solvent acids and glycerol as plasticizer on the antimicrobial and physical properties of chitosan films. Three types of acids were used in the same concentration, e.g. 1% acetic acid, 1% citric acid and 1% lactic acid whereas glycerol was fixed on 10% (w/w). In terms of barrier properties, chitosan film obtained by citric acid as solvent showed the lowest water vapour transmission rate (WVTR) followed by chitosan film prepared with lactic acid and acetic acid. Concerning mechanical properties, chitosan film prepared with acetic acid exhibited the highest tensile strength and the lowest percentage elongation. The expected result was obtained where plasticized chitosan films had higher percentage elongation than the unplasticized one. In this study, disc and well diffusion method were used against bacteria, yeast and fungi to characterize antimicrobial activity of the obtained films. When the disc diffusion method was used, all of chitosan films showed an inhibition activity against E. coli, B. cereus and S. aureus whereas no inhibition against Penicillium sp. and Candida sp except chitosan film prepared with acetic acid that showed inhibition against Candida sp. The same result was observed by using well diffusion method with the exception of chitosan solutions prepared with acetic acid solution where they also showed inhibition activity against Penicillium sp. and Candida sp.

Nanoreinforcement of Pectin Film to Enhance its Functional Packaging Properties by Incorporating ZnO Nanoparticles

The main objective of this study was to enhance functional packaging properties of pectin film by using zinc oxide nanoparticles (ZnO-NPs) as nanoreinforcing agent. Pectin/ZnO bio-nanocomposite films were fabricated at 4 levels of ZnO-NPs, i.e., 0.5, 1.0, 2.0 and 5.0% (w/w). The effects of ZnO-NPs incorporation on improving the mechanical properties and water resistance of the films were investigated. ZnO-NPs were successfully incorporated into pectin films by nanodispersion technique followed by casting method. The presence of ZnO-NPs inside pectin films was observed clearly by SEM. The improvement in tensile strength could be achieved with ZnO-NPs incorporation without obvious loss in elasticity. Potential antimicrobial activity of pectin-ZnO nanocomposite films was proved in the absence of mold after exposing them at 97% RH and room temperature for 14 days, whereas the growth of mold had been observed in pure pectin film after 3 days of exposure. In terms of film transparency, the significant change in film opacity was only found in the film prepared with 5% of ZnO. Results suggested that it would be favorable to prepare pectin/ZnO nanocomposite film by using ZnO-NPs at the amount of 2% (w/w) in the future work.

Physico-Mechanical Properties of Starch-Based Nanocomposite Film Incorporated with Hydrothermally Synthesized Zinc Oxide Nanoparticles

Zinc oxide nanoparticles (ZnO-NPs) were successfully prepared by hydrothermal method at low temperatures (80°C) for 2 hours using zinc nitrate as starting materials. The average size of hydrothermally synthesized ZnO-NPs were comparable with commercial one as confirmed by Particle Size Analyzer (PSA). The incorporation of hydrothermally synthesized ZnO-NPs (0.5% and 1%, w/w) and glycerol as plasticizer (20%, w/w) into tapioca starch film significantly reduce water absorption capacity and water vapor transmission rate while increasing tensile strength and elongation at break of the composite film. These results suggest that hydrothermally synthesized ZnO-NPs have the potential as nanofiller to improve the physical and mechanical properties of biobased film.

Preparation and Characterization of Bionanocomposite Films Made from Carrageenan, Beeswax and ZnO Nanoparticles

The objective of this study was to develop biopolymer based films as alternative of synthetic petroleum based-packaging. The ZnO NPs (0.5 and 1% w/w carrageenan) and beeswax (3% v/v), as hydrophobic component, were incorporated into carrageenan polymer to produced bionanocomposite films. The resulting films were characterized using SEM. The physical and mechanical properties of films were also investigated. The addition of ZnO NPs and beeswax resulted in different morphological surface as well as influenced the surface color of carrageenan film. Incorporation of ZnO NPs increased TS and EAB of the film, while WVTR decreased. Furthermore, the presence of beeswax within the carrageenan and or its nanocomposite films promoted synergistic effect with ZnO NPs in reducing WVTR and EAB, however decreased TS of films. Therefore, these bionanocomposite films were potentially used in packaging industry to maintain the quality of food stuffs.