Optimization, characterisation, and stability of chitosan-cellulose nanocrystal nanocomplexes

The growing demand for sustainable and functional materials in the food industry has intensified the search for biodegradable systems capable of enhancing food quality, safety, and shelf life. In this context, this study aimed to develop and characterise polyelectrolyte complexes based on chitosan and nanocrystalline cellulose at varying molar ratios (3:1, 6.5:1, and 10:1), targeting their potential applications as delivery systems or functional ingredients in food formulations. The nano complexes were evaluated for physicochemical properties, colloidal behaviour, and thermal stability. Fourier transform infrared spectroscopy confirmed the formation of hydrogen bonding interactions between the biopolymers, while thermogravimetric analysis demonstrated the enhanced thermal stability of the polyelectrolyte complexes compared to the individual polymers. Long-term stability tests conducted over 30 days at 7 °C and 25 °C revealed that the 3:1 ratio produced the most stable dispersion, with minimal aggregation and consistent particle size. These results highlight the potential of CHI:CNC nanocomplexes, particularly at a 3:1 ratio, as promising, thermally stable, and biocompatible systems for applications in food technology aimed at improving the performance and shelf stability of bioactive compounds.