2. Experimental
2.1. Materials
The initial oil-in-water emulsions were prepared by vigorous
stirring oil (sunflower refined deodorized oil) and emulsifier solution
(gelatin or its mixture with -carrageenan in water) at room
temperature. In all cases, oil–aqueous phase volume ratio was 3:2
(concentration of ϕо = 60%). Stirring was realized during 10 min at
10,000 rpm using a mixer (IKA, RW 16 basic, three-blade propeller
nozzle is used). Once produced, the samples of emulsions were
carefully put into volumetric cylinders where they were further
concentrated by sedimentation for 48 h. After sedimentation, the
highly concentrated emulsions (cream) of oil volume fraction of
ϕ = 74–75% were carefully separated from supernatant. The rootmean-square
error of oil volume fraction measuring was not more
than ca. 2%. Employing droplet size measurements, it has been
shown that droplets do not coalesce during sedimentation. Highly
concentrated emulsions were stable against coalescence during the
entire period of observation (1 month).