Effect of Dip-Coating Immersion Time of Mangosteen Peel Extract on Alginate/Banana Fiber Biopolymer as a Biodegradable Antibacterial Absorbent Material

Abstract

The increasing use of synthetic superabsorbent polymers in hygiene products has raised environmental and health concerns due to their non-biodegradable nature and potential chemical residues. This study investigated the effect of dip-coating immersion time on the physical, antibacterial, and biodegradable properties of an alginate/banana fiber biopolymer incorporated with mangosteen peel extract. The biopolymer films were prepared using sodium alginate and banana fiber obtained from the banana pseudostem at ratios of 10/90, 30/70, and 50/50, with untreated samples used as the control and coated samples treated with 15% mangosteen peel extract for 30, 60, and 90 minutes. The films were characterized by liquid absorption capacity, antibacterial activity against Staphylococcus aureus, biodegradability through the soil burial method, and FTIR analysis. The results showed that the 50/50 alginate/banana fiber ratio exhibited the highest absorption capacity among the coated samples at 90 minutes, reaching 5.88 times its initial weight. In contrast, the highest antibacterial activity was obtained at 30 minutes of immersion, with an inhibition zone of 9.3 mm against S. aureus. Biodegradation testing confirmed that the biofilms were degradable in soil, while FTIR analysis revealed characteristic functional groups and indicated physical interactions between the biopolymer components and mangosteen peel extract.