Prediction of emulsion color from droplet characteristics: dilute monodisperse oil-in-water emulsions

The influence of droplet characteristics on the transmission of light through dilute monodisperse oil-in-water emulsions was investigated in the presence and absence of dye. The turbidity spectra and tristimulus color coordinates (L*, a*, b*) of a series of n-hexadecane oil-in-water emulsions with different disperse phase volume fractions (φ=0–0.02 wt%), mean droplet radii (r=0.1–1 μm) and red dye concentration (0 and 0.002 wt%) were measured. The dependence of the optical properties of colored and non-colored emulsions on droplet size and concentration could be qualitatively described by light scattering theory. Nevertheless, there was relatively poor quantitative agreement between theory and experiment because of the influence of the measurement system on the optical properties of emulsions. The information presented in this paper will facilitate the formulation of dilute food and beverage emulsions with specific optical characteristics.