Fortification of Chocolate Bars by Eggshell Derived Calcium Carbonate Nanoparticles: Study of Physicochemical Properties and Sensory Acceptability

Abstract Eggshells are an abundant biowaste rich in calcium carbonate, offering a sustainable source of bio-derived materials with potential applications in food fortification and beyond. In this study eggshells were processed into eggshell-derived calcium carbonate nanoparticles (ESDNPs) which were then incorporated into chocolate as a model lipid-rich matrix to evaluate their potential for calcium fortification and explore possible nano–bio–food interactions in food system. The Nano-formulated eggshell powder was incorporated into the chocolate at different substitution levels of 0%, 5%, 10%, 15%, 20%, and 25%. Comprehensive characterization of the nanoparticles and fortified chocolate was performed using a various technique like DLS, TEM, XRD, FTIR and atomic absorption spectroscopy (AAS) inn addition, the chemical composition, physical properties, and sensory evaluation of the fortified chocolate. TEM images and XRD confirmed nanoparticle morphology, crystallinity. FTIR and AAS confirmed the integration within the chocolate matrix. The calcium content of fortified chocolate increased proportionally to the inclusion level reaching up to 6,230 mg/100 g for the 25% inclusion sample. Textural analysis revealed a dose-dependent increase in hardness and inversely decrease in cohesiveness. The sensory evaluation indicated high consumer acceptability up to 15% ESDNPs incorporation. The findings highlight chocolate as an effective vehicle for nano-calcium delivery and demonstrate its potential as a model system for studying nano–bio–food interactions. This work provides a foundation for designing functional food systems and opens avenues for innovative applications of biogenic nanomaterials across food technology, materials science, and biomedical domains.