Enhancing Plant Protein-Based Bioplastics with Natural\nAdditives: A Comprehensive Study by Experimental and Computational\nApproaches

Motivated\nby earlier discoveries, this study aims to enhance the\nproperties of bioplastic films from two combined plant proteins (proteoposites)\nby incorporating natural additives, microfibrillated cellulose (MFC),\nand olive stone powder (OSP). To demonstrate the effect of the protein\nstructure on interactions with additives, binding affinities of corn\n(zein) and soy proteins with MFC/OSP lignocellulosic constituents\nwere investigated using computational protein–ligand docking.\nThe obtained results indicate favorable interactions of zein macromolecules\nwith lignin, while soy proteins interact more readily with cellulose\nand hemicellulose. Computational findings were validated by mechanical\ntesting of the modified OSP and MFC proteoposites, where most property\n(tensile stress) improvements are revealed for the films where lignin-containing\nOSP is incorporated into zein. Furthermore, a reliable machine-learning-based\nquantitative structure–activity relationship model to predict\nthe tensile stress of MFC-modified proteoposites was established to\neffectively predict experimental outcomes [>70% accuracy (R<sup>2</sup>)]. As a result, adding MFC into the soy protein fraction\nof proteoposites\nenhances mechanical performance and barrier properties. Overall, this\nstudy provides valuable knowledge on a sustainable approach to making\nbioplastics from combined zein and soy proteins modified with natural\nlignocellulosic additives.