Isolasi Selulosa Nanokristal dari Serat Ijuk (Arenga pinnata) Menggunakan Microwave dan Pemanfaatannya sebagai Pengisi pada Film Kemasan Biokomposit Berbasis Pati Talas yang Ditambahkan Ekstrak Sereh

Abstract

The purpose of this study was to analyze the effect of microwave power level and alkalization time on the characteristics of nanocrystalline cellulose from palm fiber, to analyze the effect of adding nanocrystalline cellulose and lemongrass extract to the characteristics of biocomposite films, and to analyze the effect of adding lemongrass extract on the antimicrobial properties of biocomposite films. In this study, palm fiber was alkalized using a microwave with various power levels of 224, 308, and 401 watts for 45, 55, and 65 minutes. Then proceed with the bleaching process using hydrogen peroxide (H2O2) and hydrolysis using 60% sulfuric acid (H2SO4). The starch used in this study came from taro tubers. The casting method is used in the manufacture of bioplastics and biocomposites with the addition of nanocrystalline cellulose as a filler of 2–8% and lemongrass extract as an antimicrobial agent of 6–24%. The results of the XRD analysis showed that the highest crystallinity index was obtained for nanocrystalline cellulose with a power of 401 W and an alkalization time of 65 minutes, which was 86.61%. FTIR analysis showed that the obtained cellulose nanocrystals were free from impurities such as lignin and hemicellulose. FE-SEM results show that cellulose nanocrystals are spherical or spherical in shape, oval and irreguler with an average size of 58.6 nm. The FTIR results on the biocomposite showed sharper absorption peaks as the composition of the nanocrystalline cellulose and lemongrass extract increased. The best results for tensile strength and water vapor transmission rate were 13.08 MPa and 2.29 gram/m2/hour obtained by adding 4% nanocrystalline cellulose and 18% lemongrass extract. This is supported by the results of SEM analysis, where the morphology of the biocomposite showed a better dispersion of nanocrystalline cellulose. The best value of elongation at break was 7.82%, which was obtained by adding 2% nanocrystalline cellulose and 24% lemongrass extract. The best value of the water solubility test was the addition of 8% nanocrystalline cellulose and 0% lemongrass extract, with a value of 17.99%. The thermal stability of the biocomposite filled with nanocrystalline cellulose with and without the addition of lemongrass extract was better than the thermal stability of taro starch films, characterized by an increased degradation temperature at a weight loss of 5–75%. Fish meat packed with biocomposite film with the addition of citronella extract 18 and 24% can extend the shelf life of fish meat as indicated by the results of the Total Plate Number (ALT) test which exceeded the maximum ALT limit on the 5th day of storage.