An increase in a solution's viscosity by an increase in polymer concentration is generally associated with a decrease in sweetness intensity. We investigated the nature of these so called 'texture-taste interactions' (physical versus cross-modal) using sucrose solutions (csuc: 50g/L) thickened with varying polymer types (HPMC, guar gum, xanthan) and concentrations. The viscosity and sucrose self diffusion coefficient (Dsuc) of solutions were determined by rheological measurements and 1H-NMR, respectively. From the rheological data, the random coil overlap concentration (c*) and Kokini oral shear stress (t), a physical parameter known to correlate well with in-mouth viscosity, were calculated. Sweetness intensity and in-mouth thickness were assessed sensorially by a 26-member trained panel. For each polymer 't' and 'in-mouth thickness' were positively correlated and could be used to model sweetness intensity. By direct comparison, iso-thick HPMC, guar gum and xanthan solutions were rated as iso-sweet if the polymer concentrations were below c*. These findings support a mechanism based on cross-modal texture-taste interactions with in-mouth thickness driving sweetness intensity. Above c*, iso-thick solutions were not necessarily rated iso-sweet. This may be attributed to the sucrose mobility (expressed as Dsuc) which was a function of both polymer type and concentration. We suggest that below c*, sweetness intensity of polymer solutions is mainly explained by in-mouth thickness. Above c*, upon formation of a polymer network, sucrose mobility and accessibility to the taste receptors seem to play an additional role. This hypothesis is currently tested for more polymers.

Sweetness intensity of sucrose sweetened polymer solutions is explained by physical and cross-modal interactions with their relative contribution depending on polymer type and concentration

245th National Meeting (2013)

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