Sustainable Biopolymer Packaging Utilizing Non-Food-Competing Starches Derived from Rubber Cassava and Banana Wastes

This study investigates the potential of starch extracted from underutilized agro-industrial resources as non-food-competing raw materials for the development of flexible bioplastics for food packaging applications. Starch was extracted from three biomass sources: rubber cassava (Manihot glaziovii), banana stem, and banana peel from Ambonese banana (Musa acuminata L.). Rubber cassava starch (SRC) exhibited the highest starch yield (50.68 ± 0.28%), significantly surpassing banana stem (SBS, 14.20 ± 0.25%) and banana peel (SBP, 3.07 ± 0.15%). The amylose contents of SRC, SBS, and SBP were 28.18%, 52.80%, and 56.57%, respectively, while their amylopectin contents were 71.83%, 47.20%, and 43.43%. FTIR spectra confirmed the absence of cyanogenic groups in SRC, indicating its safety for packaging applications. XRD analysis revealed that PSRC films were predominantly amorphous, while PSBS and PSBP showed higher crystallinity. The enhancement of mechanical properties, specifically PSBS, showed the highest tensile strength at 16.04 ± 0.56 MPa, whereas PSRC demonstrated the highest elongation at break at 23.57 ± 0.40%, which could be attributed to the inherent characteristics of the starch sources. Additionally, PSRC film exhibited the highest transparency at 60.2%, the greatest water solubility at 34.92%, and the lowest water contact angle at 41.58°, confirming its more hydrophilic nature compared to other films. This work highlights the potential of low-cost, sustainable, and non-food agro-industrial starch sources as promising candidates for the development of flexible, eco-friendly bioplastics.