By Camille Kapaun
B.S., Food Science, Expected 2016
Rawlings Cornell Research Scholar
My study looked at the difference in how spiciness (chemical heat) and elevated temperature (physical heat) affect people’s perception of the basic tastes: salty, sweet, sour, bitter, and umami. Sixty six (66) panelists tasted and rated solutions of basic tastes served at different temperatures (for hot), or with different capsaicin levels (for spicy). Studying the influence of physical or chemical heat on taste is not a new idea (see Lawless and Stevens, 1984; Prescott et al, 1993), however we attempted to first calibrate these stimuli to deliver an equal amount of “heat”. The study was conducted over four sessions during the Fall 2015 and Spring 2016 semesters (Thank you to all the panelists who participated in this research!).
Experiment 1: Calibration
Panelists rated the perceived heat of five solutions of deionized water on the general Labeled Magnitude Scale (gLMS), ranging from room temperature to 70ºC.
On the same scale, panelists rated the sensation of heat from solutions of capsaicin ranging from 0 to 12.5uM.
Experiment 2: Control
Concentrations of the 5 basic tastes in this session were designed to represent “low,” “medium,” and “high” of each taste delivered at room temperature.
Participants tasted fifteen solutions of varying concentrations of prototypic basic tastants.
Experiment 3: Hot
Solutions in this session were the same as the control session, but now served at an elevated temperature.
Experiment 4: Spicy
Solutions in this session were the same as the control session, but mixed with capsaicin, delivered at room temperature.
Results:
The results showed that chemical and physical “heat” have a fundamentally different effect on the perception of flavor.
Humans are thought to sense both heat and capsaicin though the same channel, TRPV1 (see Caterina et al, 1997; Ishida et al, 2002). Therefore, a similar modulation of all of the five basic tastes by capsaicin or heat was expected. But, what we saw was that bitter seems to be the exception, being much more powerfully inhibited by capsaicin than any of the other tastes (salty, sweet, sour, and umami).
This would seem to imply that spiciness may be an effective bitter blocker.
So, next time you are not liking your bitter broccoli, try some hot sauce on top and see if it makes a difference!
Preparing the solutions at Dando Lab (Stocking 255)
Ready for my experiment (Sensory Kitchen, Stocking West 124)
Waiting for the first panelist. My friends and lab mates helped me to serve the samples (Sensory Kitchen, Stocking West 124)
Panelists are evaluating the samples in the Sensory Booths (Stocking West 120)
Thank you to all who participated in this research project!
References:
Caterina MJ1, Schumacher MA, Tominaga M, Rosen TA, Levine JD, Julius D. The capsaicin receptor: a heat-activated ion channel in the pain pathway. Nature. 1997 Oct 23;389(6653):816-24.
Ishida, Y., Ugawa, S., Ueda, T., Murakami, S., & Shimada, S. (2002). Vanilloid receptor subtype-1 (VR1) is specifically localized to taste papillae. Molecular brain research, 107(1), 17-22.
Lawless,H.T. and Stevens,D.A. (1984) Effects of oral chemical irritation on taste. Physiol. Behav., 32, 995-998.
Prescott, J., Allen, S. and Stephans, L (1993) Interaction between oral chemical irritation, taste and temperature. Chem. Senses, 18, 389-404.
