Development of antimicrobial bioplastics incorporation with Malaysian herbs extracts: orthosiphon staminues (misai kucing), and strobilanthes crispus (black face general) / Shirey Wong Ling Ling

Faculty of Chemical and Process Engineering Technology

Final Year Report (Bachelor of Chemical Engineering Technology) -- Universiti Malaysia Pahang Al-Sultan Abdullah - 2024

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Focusing on palm oil-derived cellulose, the research helps solve the pressing need for environmentally friendly substitutes in the plastics industry by advancing the development of sustainable and biodegradable packaging solutions. The integration of plant extracts, specifically Orthosiphon stamineus and Strobilanthes crispus, is the focus of this thesis in response to the growing demand for sustainable food packaging alternatives to standard plastics. The purpose of this research is to produce a bioactive plastic that is derived from cellulose with the added properties of antimicrobials from Malaysian herbs by enhancing the performance of bioplastics, with an emphasis on the synergistic effects inside the bioplastic matrix. The formation of bioactive film incorporated with different types of Malaysian herbs, Strobilanthes crispus and Orthosiphon stamineus, was prepared using the manual plate casting technique. The essential oil from the herb were extracted using microwave assisted extraction. The cellulose acetate film solution was incorporated with 1%, 3%, 5%, and 7% v/w of essential oils extracted from the herb. In order to compare different types of herbs and variations in the best concentration of essential oils, the biodegradable bioactive film was investigated using a variety of methodologies, including extraction of essential oil, agar disk diffusion method (antimicrobial test), water absorption test, mechanical properties by tensile strength, and Young's modulus and elongation at break, Fourier Transform Infrared Spectroscopy (FTIR), density measurement and calorimetry analysis. The extracted essential oils from SC and OS were 0.04 g essential oil/g herbs, and 0.03 g essential oil/ g herbs, respectively. The results of the antimicrobial test showed that the concentration of SC and OS EO over 3% v/w was adequate to prevent the growth of Escherichia coli strains at inhibition zones of 0.30 cm. The greatest water absorption percentage for SC 7's water absorption test was 148.74%, which complies with the highest level of bioplastic flaws. OS 7 produced the greatest results, achieving 52.28% in the water absorption test. Outcomes of the highest tensile strength, elongation at break Young’s modulus analysis were OS 5, SC 5 and OS 5 (3.06 MPa, 36.44% and 11.54 MPa) among the films. According to this result, the ideal essential oil content for the formulation of bioplastic film was determined to be 5% v/w. The presence of antimicrobial functional groups in every herb extract film was demonstrated by FTIR data, which also demonstrated that new functional groups had been added to the films based on changes in spectrums between the herbs and control films. As the concentration of EO increased, the density value for OS films increased from 1.04 to 1.18 g/cm3, but the density value for SC fell from 0.97 to 0.88 g/cm3. Furthermore, the calorimetry analysis showed the bioplastic sheet attained stable temperature around 28–30.3 °C. Since most of the bioplastic stabilized at a steady temperature after just 6-7 minutes, the combustion process appears to be moving quickly. The outcome suggested that the percentage of water absorption uptake for OS would decrease with increasing essential oil content in the cellulose acetate solution, but the opposite would be true for SC, which would result in stronger tensile strength and elongation at break but lower Young's modulus values. In conclusion, OS-incorporated biodegradable film containing cellulose acetate is a good substitute for active packaging material, having the best volume at 5 v/w%