Taste properties of cocoa drinks with an added bitter/sweet sugar: intensity/time effects

Cocoa drinks treated with either sucrose or the bitter/sweet sugar, methyl α-D-mannopyranoside were evaluated for their intensity/time response determined by taste panellists using a moving chart recorder. Both additives caused an increase in persistence as well as intensity of response, sucrose for sweetness and methyl α-D-mannopyranoside for bitterness.
Tasting of the sucrose-treated drinks, after presaturating panellists' tongues with quinine sulphate solutions, caused no significant differences in perceived sweetness. However, presaturating panellists' tongues with sucrose solution did cause significant differences in bitterness perception of the drinks containing methyl α-D-mannopyranoside.
These results accord with a previous observation of the taste response to methyl α-D-mannopyranoside in pure water and suggest that the bitter/sweet molecule may exert its effect by simultaneously spanning both basic taste receptors.