Stability and rheology of water-in-oil high internal phase emulsions containing continuous phase solid fat

The effect of solid fat added to the continuous phase of water-in-oil (W/O) high internal phase emulsions (HIPEs) was assessed for its effects on droplet size, microstructure, and rheology during storage for one month. The emulsions consisted of 76 wt% water, and a continuous phase composed of up to 2.4 wt% fully hydrogenated soybean oil (corresponding to 10 wt% of the oil phase), polyglycerol polyricinoleate as surfactant, and soybean oil. The presence of solid fat added was generally beneficial to the resistance of the dispersed aqueous phase against coalescence. The HIPE containing 2.4 wt% solid fat showed the highest rigidity and brittleness at all time points during storage, but also the lowest thixotropic recovery. Together, these results demonstrated that addition of low amounts of solid may be used to produce HIPEs with rheological properties akin to blends of solid fat and liquid oil, thereby offering an option for reducing the fat content of many processed foods.