Encapsulation of β-carotene in Pickering emulsions stabilized by self-aggregated chitosan nanoparticles: Factors affecting β-carotene stability

For conventional emulsions used to encapsulate easily degradable bioactive compounds, achieving small droplet size and high encapsulation capacity is a challenging. Pickering emulsions stabilized by self-aggregated chitosan particles may offer high encapsulation efficiency due to the robust mechanical barrier formed by solid particles adsorbed at the oil-water interface. Therefore, the effects of pH, chitosan concentration, oil volume fraction, homogenization pressure, and homogenization cycle on the stability of chitosan Pickering emulsions and the degradation of β-carotene were investigated. Effective interfacial adsorption of chitosan nanoparticles and moderate homogenization intensity facilitated the formation of small emulsion droplets. Unlike conventional emulsions, chitosan Pickering emulsions with smaller droplets provided enhanced protection for β-carotene. This enhancement was primarily attributed to the improved interfacial coverage of chitosan nanoparticles with smaller droplet sizes, which was advantageous for β-carotene protection. The optimal conditions for preparing β-carotene-loaded chitosan Pickering emulsions were as follows: pH 6.5, chitosan concentration of 1.0 wt%, oil volume fraction of 20 %, homogenization pressure of 90 MPa, and 6 homogenization cycles. These findings indicate that chitosan Pickering emulsions are well-suited for encapsulating β-carotene with both small droplet size and high encapsulation efficiency.