Perception of creaminess of model oil-in-water dairy emulsions: Influence of the shear-thinning nature of a viscosity-controlling hydrocolloid

Abstract

Butter fat-in-water emulsions, stabilized by sodium caseinate, and with well-defined droplet-size distribution and rheological properties, have been assessed with respect to sensory perception of ‘taste’, ‘thickness’ and ‘creaminess’. Two different hydrocolloids were separately used to adjust the apparent viscosity of the systems: maltodextrin and xanthan. Particular sets of conditions were chosen so that samples had the same apparent viscosities at high shear-rate (50 s −1). The influence on texture perception of vanilla flavour (0–0.1%), oil volume fraction (5–20 vol%), and the type of added thickener (maltodextrin or xanthan) has been evaluated. Physical characterization of the emulsions was controlled with respect to average droplet size and non-Newtonian rheology. The sensory results show that while the addition of vanilla flavour greatly improved the perception of taste of the model dairy emulsions, it did not significantly influence perception of thickness and creaminess. Both these sensory textural properties were substantially influenced by the emulsion viscosity and to a lesser extent by the fat content. That is, the ratings of creaminess and thickness were strongly correlated, and the higher values of both were attributed to samples of higher viscosity and higher oil volume fraction. Emulsion samples prepared with the two biopolymers (maltodextrin and xanthan) having the same apparent viscosity were found to give significantly different levels of perceived creaminess. Our main conclusion is that the apparent viscosity at 50 s −1 is insufficient to describe fully the perceived thickness or creaminess of these model emulsions.