Physical and Antimicrobial Properties of Hydroxypropyl Starch Bio-plastics Incorporated with Nyamplung (Calophyllum inophyllum) Cake Extract as an Eco-Friendly Food Packaging

Abstract

Nyamplung (Calophyllum inophyllum) cake as a by-product of nyamplung oil production is still limited. This research aimed to evaluate characteristics of antimicrobial bio-plastic made from hydroxypropyl starch as a basic ingredient and Nyamplung cake extract as additive. Nyamplung cake extract addition affected bio-plastic mechanical property by reduction of tensile strength but improved physical properties by reduction of vapor and oxygen permeability, water solubility, and increased elongation. This was probably due to the extract serve as natural crosslinking. Fourier Transform Infrared Spectroscopy analysis showed no difference in five bio-plastic samples, which probably caused by low concentration of extract. Thermogravimetry analysis showed the highest weight reduction in control of 95.824% and the lowest on Ext2% of 84.471%. Morphology analysis showed agglomeration of the extract on sample surface due to uneven ingredient distribution in mixture. Bio-plastic was more sensitive against gram positive bacteria than gram negative with their respective largest inhibition zone of 30 mm (Staphylococcus aureus) and 23 mm (Escherichia coli). This was probably due to the content of the extract serve as natural crosslinking and antibacterial agent.