Influence of Emulsifiers on Physical Properties of Oil/Water Emulsions Containing Ostrich Oil

Abstract

The fabrication of oil/water (O/W) emulsions in order to prepare the spray-dried encapsulated bioactive ostrich oil emulsions can be useful for increasing stability of commercial products. In this study, O/W emulsions were stabilized with mixed emulsifiers (Span and Tween) or soy lecithin. The effects of emulsifiers on the physical properties of emulsions containing ostrich oil were investigated. Results showed that the addition of a mixture of Span and Tween emulsifiers at concentrations between 5 and 15% w/w reduced the droplet size of the emulsions but did not decrease the zeta potential in the emulsion system. The smallest droplet size of 5.01±0.43 μm was obtained from the emulsion containing 15% w/w mixture of Span 20 and Tween 80. The zeta potential values of all emulsions containing a mixture of Span and Tween emulsifiers in the concentration range of 5 to 20% w/w were between-23 and-55 mV. In addition, the viscosity of these emulsions increased with increases in the concentrations of both emulsifiers. The stable 20% w/w ostrich oil emulsion stabilized with 15% w/w Span 20/Tween 80 presented viscosity equal to 69.56±1.82 cP. For 10% w/w ostrich oil emulsions stabilized with lecithin, the droplet size and zeta potential of the emulsions tended to decrease with increasing lecithin concentrations. An emulsion containing 10% w/w lecithin exhibited the smallest droplet size (3.93±0.11 μm). The zeta potential values of all emulsions composed of 1-15% w/w lecithin were between-33 and –66 mV and the viscosity of these emulsions increased with increases in the concentrations of lecithin. The stable 10% w/w ostrich oil emulsion stabilized with 10% w/w lecithin exhibited a high viscosity of 172.50±1.01cP. In summary, 10% w/w lecithin provides better emulsion stability than 15% w/w Span 20/Tween 80. These results therefore reveal important parameters for the fabrication of stable O/W emulsions containing ostrich oil.