Effects of oral chemical irritation on tastes and flavors in frequent and infrequent users of chili.

The studies reported here addressed the question of whether the pungent principle in chilies, capsaicin, suppresses taste and flavor intensity. Over a period of several minutes, groups of frequent and infrequent eaters of chili repeatedly rated the taste and flavor intensities of sweet and sour solutions that also contained either orange or vanilla flavor, and capsaicin at 0, 2, 4, and 16 ppm. As well as the intensity of the qualities while in the mouth, measures of the number of rating periods for the intensity to dissipate to zero, and the summed total intensity were also derived. Infrequent chili users rated the capsaicin burn as more intense than did the frequent users. With few exceptions, and for groups, sweetness was suppressed by the presence of capsaicin. By contrast, sourness was unaffected by capsaicin. Flavor intensities also showed suppression by capsaicin. High correlations between ratings of sweetness and flavor were found, suggesting that perceptual confusion between the two qualities may have been responsible for the flavor suppression. A second experiment examined the effects of capsaicin on ratings of strawberry flavor alone. This study produced little evidence of flavor suppression by capsaicin. These results are discussed in terms of an attentional model of capsaicin's effects.