Correlation between saltiness perception and shear flow behaviour for viscous solutions

Salt plays a major role in the human diet and food as tastant, flavour enhancer, nutrient, preservative and structuring aid. While intake of salt is part of a healthy diet, the vast majority of people in the developed world consume salt at a level high enough to place them at risk of developing diet induced illnesses. Salt intake is predominantly from processed foods. In this study it has been investigated whether careful choice of the viscosity behaviour of food thickeners, as used in processed foods, is exploitable to enhance saltiness perception and therefore allows reducing the content of salt in processed foods without compromising flavour. Two polysaccharides, dextran and guar gum, forming Newtonian and shear-thinning aqueous solutions, respectively, were chosen as representative non-ionic food thickeners. Absence of charge allowed to study the effect of added salt ions on saltiness perception without having to take into account charged induced binding, which also rendered the viscosity behaviour independent of the salt level. Solution concentrations were varied to match shear viscosity at low and at high shear rate and saltiness perception from these solutions was assessed by trained panellists. Saltiness perception correlated inversely to viscosity measured below 50 s−1. Saltiness perception was enhanced in samples based on lower molecular weight polymer when contrasted at matched low shear viscosity. Perceived thickness correlated to shear rates around 500 s−1.