Inhibition of droplet flocculation in globular-protein stabilized oil-in-water emulsions by polyols

The influence of neutral cosolvents (polyols) on the stability of hydrocarbon oil-in-water emulsions stabilized by a globular protein was investigated. Glycerol (0–40 wt%) and sorbitol (0–35 wt%) were added to n-hexadecane oil-in-water emulsions stabilized by β-lactoglobulin (β-lg, pH 7.0, 150 mM NaCl), either before or after incubation at 30 °C for 24 h. The stability of the emulsions to flocculation and creaming improved when neutral cosolvents were added, with the effectiveness of the cosolvents depending on their type, concentration and time of addition. Emulsion stability was better for sorbitol than glycerol, improved with increasing cosolvent concentration, and was better when the cosolvents were added immediately after homogenization than when they were added 24 h later. The influence of the cosolvents on emulsion stability is interpreted in terms of their effect on the conformation and interactions of the adsorbed proteins, as well as on the droplet–droplet collision frequency. This study has implications for the development of protein stabilized oil-in-water emulsions for utilization in industrial products.