Sweetness perception in protein-polysaccharide beverages is not explained by viscosity or critical overlap concentration

It is generally reported that in random coil polysaccharide solutions, increasing polymer concentration above the critical overlap concentration (c(star)) results in decreased taste perception due to a high degree of polymer entanglement and resultant poor mixing efficiency with saliva in the mouth. However, these reports are commonly based on aqueous solutions of polymers and it is unknown if this phenomenon applies to more complex fluids containing protein and fat, or if taste suppression can be explained on the basis of an altered temporal profile of taste. In this study, the effects of carboxymethyl cellulose (CMC) concentration (0.15-1.50% w/w) on sensory texture and sweet taste perception (6.0% w/w sucrose) were evaluated. Zero-shear viscosity of CMC solutions ranged from 5.5 to 133 mPa s, and c(star) was experimentally determined to be 0.67% w/w. Three concentrations above c(star) were tested and only the highest (1.5% CMC) caused a significant (p < 0.05) reduction in sweet taste. Moreover, when combined with milk protein concentrate to approximate the macromolecular profile of reduced fat milk, perceived sweet taste slightly increased with viscosity. Time intensity evaluations revealed a large variation in temporal perception of sweet taste among individual panelists, with time to maximum intensity ranging from 4.8 to 33.5 s. The results indicate that the critical overlap taste suppression observed in aqueous solutions of polysaccharides did not apply to a more complex fluid microstructure containing a combination of protein and fat.