Influence of droplet size and concentration on the color of oil-in-water emulsions

The influence of droplet size (0.2-15 mu m) and concentration (0-20 wt %) on the turbidity and color of n-hexadecane oil-in-water emulsions containing a blue food dye has been investigated. Emulsion turbidity was maximum for droplets with diameters of similar to 2 mu m (at 650 nm). Colorimetry measurements of the tristimulus coordinates (L,a,b) of emulsions indicated that they became less Light, more green, and more blue as droplet size increased and more light as droplet concentration increased. Sensory analysis showed emulsions became lighter and less blue as droplet size decreased and droplet concentration increased. The observed behavior can be explained in terms of the scattering and absorption of Light by emulsions. Our results show that food emulsion appearance can be optimized by carefully controlling droplet characteristics, such as size and concentration.