High internal phase emulsion stabilized by casein-nanocellulose composite with the aid of ultrasound

This study modified cellulose nanocrystals (CNC) with casein (CA) using ultrasound (U). Ultrasound treatment (U-CA-CNC) reduced particle size and created uniform filamentous networks compared to just CA-CNC. Analysis showed enhanced hydrogen bonding between CA and CNC due to ultrasound. U-CA-CNC and CA-CNC significantly improved interfacial properties: contact angle increased while interfacial tension decreased sharply. Consequently, high internal phase emulsions (HIPEs) stabilized by these modified particles, especially at CA:CNC ratios of 1:1.5 or 1:2, had smaller droplet sizes, higher elasticity (G'), and higher viscosity. These HIPEs remained stable without delamination after 15 days at 4 °C when inverted and showed lower oxidation (TBARS). Ultrasound effectively improved the CA-CNC interfacial properties, enabling stable HIPEs with enhanced rheology.