Bitterness of Ilex paraguariensis (Ip) infusions: affected by flavor manipulations or caffeine?

TAMASI, O.; GURLEKIAN, I.; DRUNDAY, F.; CALVIÑO, A.M.

Sarasota, Florida, USA

Congreso; 27th Annual Meeting of the Association for Chemoreception Sciences; 2005

Association for Chemoreception Sciences

Ip infusion, a complex sensory stimulus with characteristic flavour and bitter notes, is traditionally consumed in South America as a mild stimulant beverage. Thus, the aims of this study were: (1) to examine the bitter responses to caffeine and Ip infusions; and (2) to investigate whether there is a systematic change in bitterness due to Ip flavor information. Sixteen habitual Ip users distinguished the bitterness of caffeinated distilled water (2.5 vs 5.0 mM). Discrimination of Ip 2 %W/V vs Ip 2 %W/V + caffeine 10 mMwas determined using the R-index values outlined by O´Mahony (1992). Three concentrations of caffeine (3.25; 6.5 and 13 mM) and Ip (2.5; 5.0 and 7.5% W/V) were evaluated by magnitude estimation. Both, discrimination and intensity scaling tasks were performed with and without use of nose clips. Neither the ability to discriminate bitterness in Ip infusions nor the bitter concentration-response functions were affected by the flavor manipulation.The psychophysical bitter functions for the Ip infusions were steeper than the function for caffeine. Furthermore, this difference is stimulus dependent, both Ip brands showed comparable bitter functions. These data suggest that from the oral sensory factors, presumably taste was sufficient to produce the bitter experience. Results showed also that bitterness of Ip is mediated by caffeine plus other Ip components as caffeoyl derivatives and flavonoids.