Fabrication of pickering emulsions using cellulose nanocrystals-chitin-glucan nanofibers as stabilizer for curcumin-based delivery systems

This study focused on the development and characterization of cellulose nanocrystals (CNCs) and chitin-glucan nanofibers (CGNFs) and their synergistic application as stabilizers in Pickering emulsions (PEs) for curcumin delivery. CNCs were prepared via sulfuric acid hydrolysis and characterized by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy-Attenuated Total Reflection (FTIR-ATR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and zeta potential analysis. The results showed well-defined rod-like particles with a high crystallinity index (73.1%) and good colloidal stability. CGNFs were produced from chitin-glucan complexes (CGCs) derived from fungal sources via esterification using deep eutectic solvent (DES), resulting in an entangled nanofiber network with enhanced surface area, higher crystallinity, and strong negative surface charge (–40.8 mV). Compared to CGCs, CGNFs demonstrated significantly improved structural, thermal, and colloidal properties. Both CNCs and CGNFs were used individually and in combination to stabilize oil-in-water Pickering emulsions. The Pickering emulsions stabilized by CGNFs and CNCs showed improved physical stability, especially when combined with PGPR, forming hybrid particle-surfactant interfacial layers that resisted coalescence. The optimized PEs formulation (0.05% CGNFs + 0.1% CNCs with 5% PGPR and 40% oil) was selected for curcumin encapsulation. The resulting curcumin-loaded PEs showed high encapsulation efficiency (>97%), pH-responsive release, enhanced colloidal stability, and suitable rheological behavior. Simulated digestion and free fatty acid release confirmed effective lipid digestion and curcumin bioaccessibility. These findings support the application of CNC- and CGNF-stabilized Pickering emulsions as robust and natural delivery systems for bioactives in food and nutraceutical applications.Additionally, the cholinium-based ionic liquids were prepared through a simple metathesis reaction to enhance water solubility, and they were encapsulated by fabricating co-stabilized cellulose nanocrystals with sodium alginate and lecithin for Pickering double emulsions. The biological activity was enhanced with 86% antioxidant activity and 15-fold water solubility for curcumin. The emulsion loaded with ILs exhibited good shear-thinning properties. The creaming index and visual appearance of curcumin-based ionic liquids as double emulsions ([Ch][Cur]-CAL-C) revealed good stability of 30-day storage at 4°C and the release kinetics of 79.15% over 24 hours with high encapsulation efficiency (>96%). A promising synergistic impact on curcumin delivery to improve bioavailability and maintain molecular stability was successfully achieved in Pickering double emulsion and potentially used in food, pharmaceutical, and cosmeceutical applications.