Biobased Composites from Starch and Mango Kernel Flour

Starch is a promising alternative to petroleum-based polymers due to its biodegradability and renewable nature. However, its widespread use in non-food applications raises ethical concerns. Mango kernels, a major byproduct of mango processing, represent an abundant yet underutilized starch source. However, conventional starch extraction requires costly purification steps with significant environmental impact. This study explores the development of extruded biocomposites, using corn starch and mango kernel flour (MKF) as a more sustainable alternative. The influence of lignin, extractives, amylose, and amylopectin content on the material properties was assessed. MKF was obtained by removing both tegument and endocarp from the mango kernels, grinding them in a colloidal mill, and finally drying the ground kernels. The resulting flour was blended with corn starch, processed in an internal mixer, and injection-molded. The composites were characterized through mechanical testing, water absorption analysis, colorimetry, and UV absorption assays. Notably, the composite containing ~20% MKF exhibited mechanical properties comparable to commercial polyethylene (PE-PB 208), with a tensile strength of 9.53 MPa and a Young’s modulus of 241.41 MPa. Additionally, MKF enhanced UVA protection. These findings suggest that mango kernel flour can partially replace starch in the production of injection-molded biopolymers, offering a more sustainable approach to biodegradable plastic development.