Dual Functionality of Chitosan in Chia Oil-in-Water Emulsions: From Interfacial Behavior to Short-Term Stability

Physical stability of chitosan (CH)-based emulsions was investigated and compared with emulsions formulated with egg yolk (EY), a conventional food emulsifier. Additionally, a mixture of both components was examined to assess its potential to improve emulsion performance. Emulsion quality was characterized by evaluating interfacial properties, including interfacial tension and interfacial rheological properties, as well as the evolution of droplet size distribution using laser diffraction, optical microscopy, visual inspection, and multiple light scattering in chia-oil-in-water emulsions. Despite the higher interfacial tension reduction exhibited by egg yolk, emulsions stabilized solely by chitosan demonstrated significantly higher resistance to creaming and coalescence. In contrast, mixed CH/EY systems did not exhibit improved stability compared with CH-only emulsions. These observations indicate that emulsion stability was governed not only by interfacial properties but also by stabilization mechanisms operating in the continuous phase. Overall, the findings demonstrate that crayfish-derived chitosan can effectively function as a multifunctional ingredient in realistic multicomponent acidic food emulsions, providing both emulsifying and stabilizing capabilities and highlighting its potential for clean-label food applications.