Production and Characterization of Bioplastic From Wheat Bran Starch Reinforced With Wheat Straw Fiber by Using Response Surface Methodology

Recently, extracting bioplastics from agricultural waste and lignocellulosic biomass residues has attracted significant attention due to their low cost and availability in abundance. This study investigates the production of bioplastic films from wheat bran starch reinforced with wheat straw fiber. Proximate analyses of wheat bran and wheat straw were conducted, and the physicochemical properties of the extracted starch and fiber were evaluated using standard analytical techniques. The effects of oven‐drying temperature (35°C–55°C), glycerol concentration (30%–40% w/v), and fiber concentration (5%–15% w/w, based on starch) on the tensile strength (TS), elongation at break (EA), and water absorption (WA) of the bioplastic films were examined using response surface methodology (RSM) with a central composite design (CCD). Optimal conditions were identified at a 55°C oven‐drying temperature, 31.97% glycerol concentration, and 14.40% fiber concentration, yielding TS, EA, and WA values of 20.528 MPa, 8.1%, and 19.44%, respectively, with a desirability of 97.1%. The developed statistical model was validated and showed no significant difference between predicted and experimental results. Additional physicochemical properties of the optimized bioplastic film, including density (1.54 g/mL), moisture content (16.66%), water solubility (35%), transparency (5.6%), and thickness (0.47 mm), were also evaluated. Structural and thermal analyses were performed using TGA, XRD, and FTIR. The optimized bioplastic exhibited a degradation rate of 86.7% within 16 days, indicating its strong potential as an eco‐friendly biodegradable material.