Time-intensity (TI) methodology and a trained panel were used to characterize the perceived bitterness of Yerba mate (YM) Ilex paraguariensis infusions. Two sampling procedures (sip and spit; sip and swallow) and two conditions for residence time in mouth (free or fixed duration of 5 s until spit or swallow) were evaluated.
At a fixed duration the maximum bitterness as well as the time to reach it showed a significant YM concentration dependence. No change on bitterness was observed by swallowing or spitting YM infusions except a larger rate of decay of the response (vr) at spit condition. Dynamic bitterness at free sampling time showed that the decision period to spit or swallow the YM infusion approximately duplicated the fixed one of 5 s.