Rheological characteristics of nut creams realized with different type and amount of fats

The rheology study of complex systems made up from different solid particles dispersed in a continuous fluid, such as nut creams, is important because it is related to the efficiency of the main process steps and to the quality, stability and sensorial characteristics of final products. In particular formulation and the used ingredients become key parameters that can affect strongly their rheological properties. The effects of different types (palm oil and hydrogenated fats - HF) and amounts of fats, on the rheological and textural properties of laboratory made nut creams were evaluated. The creams were produced in roller ball mill pilot plant, and colour (hue angle, Chroma), rheological (steady and dynamic measurements) and textural (back extrusion test) characteristics were evaluated. The experimental nut creams were compared with two commercial ones. The highest amounts of HFs (50%) led to an increase of consistency, viscosity and elasticity of creams compared to ones without or with low level of HFs (25%), probably due to the presence of strongly fat networks that implies more aggregated structure. In particular, among the experimental creams, sample having in formulation 75% of palm oil and 25% of HFs showed fundamental (G’’ and K index) and textural properties similar to the commercial cream leader of market. Moreover it was found that the increase of HFs quantity in creams involves a reduction in hue angle and chroma values. Finally, both fundamental and empirical considered parameters resulted to be equally useful and sensitive in discriminate rheological properties of the different cream samples.