Fabrication and characterization of citral-loaded oil-in-water Pickering emulsions stabilized by chitosan-tripolyphosphate particles

Citral-loaded oil-in-water Pickering emulsions were fabricated with chitosan-tripolyphosphate particles (CS-TPP Ps) as stabilizers using a high-shear rotor homogenizer. The influence of the contents of CS-TPP Ps on the physical and chemical properties of the Pickering emulsions was investigated at 40 °C for 14 days. The morphology and chemical stability of the citral-loaded Pickering emulsions were determined by laser diffraction, optical microscopy, confocal laser scanning microscopy and solid-phase microextraction-gas chromatography (SPME-GC). Results showed that the droplet size of the Pickering emulsions decreased from 14.4 to 11 μm as the concentration of CS-TPP Ps increased. The droplet size of the Pickering emulsion with 0.6% w/v CS-TPP Ps remained unchanged during storage. GC illustrated that the Pickering emulsion with 0.6% w/v CS-TPP Ps showed the best chemical stability, with 52.33% citral remaining after 14 days of monitoring. Overall, the encapsulation of citral in CS-TPP Ps Pickering emulsions enhanced its chemical stability in acidic surroundings.