Media-milled agar particles as a novel emulsifier for food Pickering emulsion

Pickering emulsions was successfully fabricated using ball-milled agar particles with sizes and sulfate content around 7 mu m and 0.62 %, respectively. These particles were obtained through a simple media-milling process using agar powders initially sized at 120 mu m. The lamellated agar is aggregated into a mass after the milling process. The surface charge and hydrophobicity of the ball-milled agar particles were characterized through zeta potential and contact angle measurements, respectively. The droplet size of Pickering emulsions was related to oil fraction and particle concentration, ranging from approximately 45 mu m to 80 mu m. Ball-milled agar stabilized emulsions were sensitive to pH and salt conditions. The results of confocal laser scanning microscopy and cryoSEM showed that at low particle concentrations and oil fractions, ball-milled agar stabilized the emulsions by dispersing particles on the surface of the oil droplets through electrostatic repulsion. Conversely, ball-milled agar stabilized the emulsions under high particle concentrations and oil fractions by forming a gel network structure to bind the oil droplets. In this research, this developed method provides the basis for the high-value application of agar and a new idea for preparing stable food-grade Pickering emulsion-based functional foods using raw-food material without surface wettability.

Automated summary

Pickering emulsions were successfully prepared using ball-milled agar particles as stabilizers. The particle size and sulfate content of the agar particles were around 7 µm and 0.62%, respectively. The stability of the emulsions was influenced by the surface charge and hydrophobicity of the ball-milled agar particles, as well as the pH and salt conditions. At low particle concentrations and oil fractions, the emulsions were stabilized by electrostatic repulsion, while at high particle concentrations and oil fractions, a gel network structure was formed.