Mutlu, BusraEroglu, Murat2026-02-082026-02-0820251022-97601572-8935https://doi.org/10.1007/s10965-025-04590-yhttps://hdl.handle.net/20.500.12885/5538Carob pod powder (CP), a neglected agro-waste material, provides a sustainable, cheap substitute for synthetic fillers, meeting the global demand for eco-friendly materials. In this context, this study investigates the incorporation of CP into polyvinyl alcohol (PVA)-based biocomposite hydrogel films to enhance their mechanical, structural, physicochemical, physical, and optical properties. The hydrogel films were prepared by dissolving PVA in distilled water, followed by the addition of CP powder at varying concentrations (5%, 10%, and 20% by weight). The mixtures were crosslinked using 6 M NaOH solution. Characterization of the prepared hydrogel samples was carried out by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), mechanical and optical testing. The results showed the addition of CP powder considerably improves the tensile strength and elongation at break of the hydrogel films, being most effective at 10% CP concentration. Hydrogel samples experienced decreasing moisture content and swelling ratios with increasing CP content, producing a more compact and hydrophobic structure. Optical properties, such as color and clarity, were affected by increased CP loadings, with darker films and reduced transparency at these higher CP levels. Thus, it can be stated that CP powder is a viable natural filler to enhance the properties of PVA-based hydrogel films for various biomedical and packing applications. We demonstrate the applicability of CP as a natural filler to facilitate sustainable hydrogel film design for biomedical and packaging applications. The work addresses both performance challenges and environmental concerns.eninfo:eu-repo/semantics/closedAccessPolyvinyl alcoholCarob pod powderBiocomposite hydrogel filmsNatural fillersMechanical propertiesSwelling behaviorArticle10.1007/s10965-025-04590-y3210WOS:0015864692000032-s2.0-105018055373Q3Q2