Effect of 1-monocaprin addition on the emulsion stability and the storage stability of mayonnaise

Emulsifiers are used in various industries, and the functional development of these emulsifiers is necessary. The objective of this study was to determine the effect of addition of 1-monocaprin on the emulsion stability and viscosity of mayonnaise as an index of storage stability. Mayonnaise made of soybean oil, egg yolk, sugar, salt, and vinegar was supplemented with 20, 40, 60, 80, and 100 ppm of 1-monocaprin. The effects of 1-monocaprin addition on storage stability and emulsion stability of mayonnaise were determined by observing changes in the average Δ-backscattering flux (%) after storage at 60°C for 24 hr. The viscosity of each sample was also measured. Mayonnaise containing 60 ppm of 1-monocaprin had the highest emulsion stability followed in order by mayonnaise containing 40, 20, 80, and 100 ppm 1-monocaprin. Analysis showed that apparent viscosity decreased at a slower rate with higher 1-monocaprin concentrations. From the above results, it could be concluded that the optimal concentration of 1-monocaprin added to mayonnaise for the emulsion stability and the storage stability was 60 ppm.     

Effects of heat flux on dropwise condensation on a superhydrophobic surface

The condensation heat transfer efficiencies of superhydrophobic surfaces that have ∼160° contact angle under atmospheric conditions were investigated experimentally. The departing diameter and the contact angle hysteresis of droplets were measured by capturing front and tilted side views of condensation phenomena with a high speed camera and an endoscope, respectively. Condensation behaviors on the surface were observed at the micro-scale using an Environmental scanning electron microscope (ESEM). Apparently-spherical droplets formed at very low heat flux q″ ∼20 kW/m² but hemispherical droplets formed at high q″ ∼440 kW/m². At high q″, heat transfer coefficients were lower on the superhydrophobic surface than on a hydrophobic surface although the superhydrophobic surface is water repellent so droplets roll off. The results of contact angle hysteresis and ESEM image revealed that the reduced heat transfer of the surface can be attributed to the large size of departing droplets caused by adhesive condensed droplets at nucleation sites. The results suggest that the effect of q″ or degree of sub-cooling of a condensation wall determine the droplet shape, which is closely related to removal rates of condensates and finally to the heat transfer coefficient.