Valorization of banana plant corm: Optimization of starch extraction using response surface methodology and development of biodegradable packaging film

Banana plant corm, a starch-rich residue left in the field after fruit harvest, has received little attention as a feedstock for bio-based materials. This study is the first to use response surface methodology (RSM) to optimize starch extraction from banana corm and link the optimized starch directly to biodegradable packaging film production. Using a face-centered central composite design, sodium metabisulfite concentration (1–3%) and soaking time (60–180 min) were varied to maximize starch yield and lightness. The optimized conditions yielded 16.05±0.17% starch with a lightness of 82.32 ±0.18. The extracted starch was successfully converted into a glycerol-plasticized film by casting. Structural analyses confirmed a semicrystalline starch matrix with strong hydrogen-bond interactions and a smooth, homogeneous morphology. The film exhibited uniform thickness (0.115±0.002 mm), moderate tensile strength (10.27±0.44 MPa), and good flexibility (72.38±1.28%). X-ray diffraction revealed an amorphous-dominated matrix, while infrared spectroscopy showed an 11.2 cm -1 shift in O–H stretching, indicating hydrogen-bond reorganization by glycerol without covalent modification. Thermogravimetry resolved four decomposition stages, with glycerol volatilization beginning at 167.9 °C and starch depolymerization at 260.3 °C. Films were transparent (70.9% at 600 nm), moderately water-soluble (32.56%), and lost 96.21% of their mass after 30 days of soil burial. Banana corm is therefore a viable feedstock for biodegradable packaging.