Food matrix impact on oral structure breakdown and sandiness perception of semisolid systems including resistant starch

Abstract In this study, the influence of matrix structure and viscosity was investigated to gain insight into the mechanisms of sandiness perception. Granules of two types of resistant starch (RS types II and III) were used as edible particles of different size (RS type II, D4,3 = 21.25 μm; RS type III D4,3 = 44.03 μm). First the impact of adding the two RS types at two levels (1.5 and 3%) on rheology (flow behaviour) and sensory properties (ranking test) of custards was determined. Second, the impact of adding an extra thickener (starch, xanthan gum, carboxymethylcellulose, λ-carrageenan, or a mixture of xanthan and carrageenan) in the formulation on the viscosity decay at constant shear of 10 s−1 with saliva and the effect in sandiness perception was studied. The presence of RS granules that remained intact after oral digestion caused a sandiness sensation which increased with increasing levels of RS. Modifying the matrix (by adding an extra thickener) affected the sandiness perception, which depended more on the nature of the thickener than on the viscosity of the system. Viscosity decay curves show the extension and rate of structural breakdown also depended on the type of thickeners. In custards with xanthan gum, the part of the structure remaining after saliva hydrolysis may explain the less intense sandiness observed in this sample.