The Effect of Betel (piper betle) leaf extract as antimicrobial agent on characteristics of bioplastic based on sago starch

Betel leaf extract contains many phenolic compound such as tannin and flavonoid which have antibacterial and antifungal properties. This study aims to investigate the effect of betel leaf extract addition in bioplastic based on sago starch (Metroxylon sp.) which includes density, water absorption, functional group characterization and antimicrobial activity. The betel leaf was extracted by using the ultrasonication method with ethanol as a solvent. Then betel leaf concentrated extract is diluted using aquadest with a concentration of 2 g/100 mL (2%) to be applied as an antimicrobial agent in bioplastics. The compositions of betel leaf extract as antimicrobials were varied in bioplastics making. The results show the highest density was 1.448 g/cm³ indicated by the variation of 9% betel leaf extract. The highest water absorption percentage was shown by sample without betel leaf extract addition (0% betel leaf extract), which was 75.56%. The antibacterial activity showed that the addition of betel leaf extract to bioplastics was able to inhibit the activity of bacteria (Bacillus cereus). The best inhibition were shown in bioplastics with a variation with 9% betel leaf extract addition. However, all variation did not show their inhibition with fungal activity (Aspergillus niger).