Stabilization of aerated sugar particle systems at high sugar particle concentrations

We report on the stability of aerated sugar dispersions containing a high concentration of sugar particles and low air phase volume with a composition typical of fondant confectionery. The main instability mechanisms are creaming of the air phase and sedimentation of the solid continuous phase. The influences of particle concentration, mean particle size and the type of particles (sugar/silica) on quiescent storage stability have been investigated. It has been found that finer particles give a lower particle settling rate and a greater sediment volume due to more attractive particle–particle interactions. The creaming behaviour is mainly affected by the concentration-dependent viscosity of the dispersion, the particle settling rate, and the time-dependent network formation at high solid concentrations. Stability differences between systems containing sugar particles and silica particles of different sizes can be attributed to differences in densities and shapes of the two kinds of particles. The minimum sugar particle concentration required for creaming stability has been estimated from the apparent yield stress of the system, the measured bubble sizes, and the density differences between the gaseous and continuous phases. Due to time-dependent network formation of sugar aggregates during ageing, the sugar particle concentration required for long-term stability is lower than that estimated on the basis of the initially measured apparent yield stress.