Stabilization by spherical cellulose nanocrystals and bacterial nanofibrils: modulating lipid digestion in fish oil‐in‐water Pickering emulsions

Abstract BACKGROUND This study explored the role of bacterial nanofibrils (BC) in regulating the structural characteristics, stability, and in vitro lipolysis behavior of fish oil Pickering emulsions stabilized by cellulose nanocrystals (CNC). The objective was to understand how different BC levels modify the interfacial organization of CNC‐based emulsions and influence subsequent lipid digestion. RESULTS CNC‐only and CNC/BC‐stabilized emulsions were initially prepared and characterized, after which the three most stable CNC/BC emulsions containing 0.2, 0.3, and 0.4 wt% BC were selected for simulated gastrointestinal digestion. The incorporation of BC reduced the droplet size and narrowed the size distribution, thereby improving the physical stability of the emulsions. Scanning electron microscopy showed spherical CNC particles associated with the oil–water interface and filamentous BC surrounding the droplets, suggesting the formation of an interfacial fibrillar network. During simulated digestion, the selected emulsions exhibited decreases in the surface‐weighted mean diameter ( d 3,2 ) and absolute zeta potential from the oral to gastric phase, followed by an increase in absolute zeta potential after intestinal digestion. Emulsions containing 0.2 and 0.3 wt% BC showed greater free fatty acid release than the emulsion containing 0.4 wt% BC, indicating that increasing the BC concentration limited the final extent of lipid hydrolysis during intestinal digestion. CONCLUSION The incorporation of BC improved the physical stability of CNC‐stabilized Pickering emulsions and modulated in vitro lipid digestion. These findings demonstrate the potential of CNC/BC‐stabilized emulsions for designing fish oil delivery systems with adjustable physical stability and lipid hydrolysis extent. © 2026 Society of Chemical Industry.