Carboxymethyl cellulose acts as an interfacial binder to reinforce and stabilize anisotropic droplets in α-cyclodextrin pickering emulsions

Pickering emulsions stabilized by biopolymers have attracted increasing attention in the food industry as clean-label alternatives to surfactant-based systems. In this study, we demonstrate that carboxymethyl cellulose (CMC) plays a previously unrecognized role as an interfacial binder in α-cyclodextrin (CD)-based Pickering emulsions. Rather than acting solely as a bulk-phase thickener, CMC selectively associates with α-CD-derived nanocrystals at the oil–water interface, reinforcing the interfacial particle network while preserving the intrinsic crystalline structure of α-CD. Electrokinetic and rheological analyses demonstrated that CMC contributes significantly to both the electrical and mechanical stabilization of the interfacial layer. Structural characterization using scanning electron microscopy and X-ray diffraction showed that CMC adsorbs onto the surface of α-CD nanocrystals as an amorphous component without disrupting their hexagonal close-packed crystalline framework. Furthermore, fluorescence microscopy observations using fluorescein isothiocyanate (FITC)-labeled CMC were conducted to directly visualize its preferential localization. FITC-CMC was found to localize at the oil–water interface. Importantly, similar interfacial localization was retained for chemically functionalized CMC bearing N -acetyl-lactosamine, demonstrating that glycan moieties can be introduced without compromising interfacial stability or droplet morphology. This interfacial binding behavior enables rational control of emulsion stability and texture using polysaccharide-based components alone, while simultaneously facilitating the introduction of functional groups at the oil–water interface. These findings establish CMC as an active interfacial component in α-CD-based Pickering emulsions and provide a general design principle for biopolymer-stabilized emulsions in advanced food formulations.