Optimizing Pickering Emulsion Stability: Modifying Zein Particle Wettability

The physical stability of Pickering emulsions is significantly influenced by the wettability of particles. This study explores the modification of zein particle wettability to enhance emulsion stability, avoiding repetition in the text.

Zein particles exhibited a contact angle (θow) of approximately 115.4° (Fig. 4A), indicating a preference for the oil phase over the water phase. The presence of over 50% hydrophobic amino acid residues within zein molecules led to aggregation in aqueous environments rather than arrangement at the oil-water interface.

In contrast, the addition of TS resulted in a range of θow values from approximately 95.7° to 84.7° with increasing TS concentration. This resulted in near-neutral wettability (θow∼90°), facilitating efficient packing of particles at the oil-water interface and preventing coalescence of oil droplets. The improved hydrophobicity was attributed to hydrogen bonding between the carbonyl moieties of zein and the hydroxyl groups of the TS. This interaction increased the hydroxyl groups on the surface of zein particles, reducing their hydrophobic nature.

A previous study demonstrated successful modification of zein particle wettability using the ionic surfactant sodium stearate through hydrophobic interaction.