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Water-in-oil-in-water (W/O/W) double emulsions present a reduced-fat alternative to conventional O/W food emulsions, as part of the dispersed oil phase is replaced with water. In this study, the concept of a reduced-fat whipped topping produced by W/O/W technology was proven. Whipping of a W/O/W emulsion, containing only 20% oil phase and a solid fat content of 78%, produced a superior whipped topping, in terms of firmness and overrun, compared to its whipped O/W emulsion counterparts. The presence of PGPR in the oil phase increased structure formation during whipping, while the additional dispersed-phase volume resulted in a better air inclusion. Two commercial monoacylglycerols (saturated and unsaturated) were investigated to improve the whipping properties of the produced W/O/W double emulsion. Both increased the susceptibility towards partial coalescence, thereby reducing whipping time and overrun, while increasing firmness of the produced whipped topping. Furthermore, the effect was stronger for the unsaturated than for the saturated monoacylglycerol.

It is well known that shear has an effect on fat crystallization. Whereas rheo-NMR has been used to study the impact of shear on the crystallization kinetics in the past, these methods mostly used a simple Teflon mixing shaft inside a sophisticated NMR instrument to apply shear to the sample. However, this method did not enable the determination of rheological parameters. In this work, a custom made low-field rheo-NMR device was evaluated, consisting of a commercial rheometer combined with a low-field permanent magnet to enable simultaneous rheological and NMR measurements. Two fats, i.e. partially hardened sunflower oil (PHSO) and soft palm mid fraction (sPMF), were submitted to several rheo-NMR experiments. The results of these experiments clearly indicated that these fats crystallized differently. First, PHSO crystallized faster than sPMF. Moreover, the latter seemed to crystallize in two steps. Initially a weak structure was formed when a low amount of solids was present, but this structure was replaced by a stronger network once more crystals were present. Both fats were studied under stagnant conditions, but also when submitted to low shear rates (1 s −1 and 5 s −1 ). It was shown that the amount of solids necessary to obtain a viscosity of 10 ​Pa ​s was higher when the shear rate was higher. The strength of the formed crystal network at a given percentage of solids was also weaker as the shear rate during crystallization increased. Whereas these experiments were done non-isothermally, it was shown that rheo-NMR can also perfectly be used for isothermal measurements.

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