1 1 Symposium Chemosensory Receptors Satellite DEVELOPMENT ...

173 Poster Multimodal, Chemosensory Measurement,Psychophysical, Clinical Olfactory, and TrigeminalINDIVIDUAL TASTE AND SMELL SENSITIVITY, AND THEIREFFECTS ON SALIVARY FLOW RATES AND FOODPERCEPTIONDe Wijk R.A. 1 , Bult H. 1 , Prinz J.F. 1 , Dransfield E. 1 1 Wageningen Centerfor Food Sciences, Wageningen, NetherlandsThe objective was to investigate the relationship between taste andsmell psychophysics and salivary flow rates of individual consumers totheir perception of the quality of semi-solid foods. Tests on 120 subjectsof pure solutions showed thresholds of 14.3, 38.6, 0.086 and 1.14 mMfor the 4 tastants NaCl, sucrose, quinine sulfate, and citric acidrespectively and 0.47 mM for the odorant, phenylethyl alcohol. Salivaryflow rates, measured as spit, increased by as much as 10 ml/mindepending on tastant and concentration. Relationships were determinedby linear regression. Among subjects, sensitivities to one tastant wererelated to those of the other tastants (r > 0.24, n = 120), but not to theodorant (r < 0.09). Except for NaCl (r = 0.21), taste sensitivities werepoorly related (r < 0.1) to salivary flow rates. Those subjects who hadrelatively high salivary flow rates in response to one tastant, alsoshowed relatively high flow rates in response to the other tastants (r >0.71). Across subjects, salivary flow rates varied more with perceivedintensity that with tastant, i.e., at iso perceived intensities, all tastantselicited fairly similar flow rates. Within certain foods, some sensoryprofile attributes (e.g. dairy taste) varied with the consumers´sensitivities, whereas others (e.g. stickiness) varied with salivary flowrate whilst `creaminess´ varied with both. In conclusion, variations inboth taste psychophysics and salivary flow among consumers accountedat least some of the variation in food sensations.174 Poster Multimodal, Chemosensory Measurement,Psychophysical, Clinical Olfactory, and TrigeminalMOLECULAR STRUCTURE PREDICTS HUMANJUDGMENTS OF PLEASANTNESS AND SIMILARITYKhan R.M. 1 , Luk C. 2 , Flinker A. 3 , Sobel N. 1 1 Neuroscience, Universityof California, Berkeley, CA; 2 Bioengineering, University of California,Berkeley, CA; 3 University of California, Berkeley, CAThe organization of olfactory perceptual space and its relation toproperties of odorant molecules is a long-standing problem. We usedolfactory descriptive attributes and asked: (1) how is the space ofattributes organized, (2) can an attribute perceptual space predictsimilarity judgments and behavior, and (3) does the perceptual spacepredict physical molecular properties. A principal component analysis(PCA) of set of 160 odorants described by experts using 146 attributes(Dravnieks, 1985) revealed that the first principal component (PC) ofthe attribute space corresponds to pleasantness (valence). Empirically,the first PC values correlated with judgments of pleasantness and tojudgments of pleasantness of each attribute. An olfactory space(Euclidean metric over the first 4 PCs) predicted subjects' judgments ina pairwise similarity task and reaction times on a speeded samedifferenttask. To compare the results to molecular properties, we used>1500 molecular descriptors (Dragon, http:// www.talete.mi.it) for eachof 144 monomolecular odorants, divided randomly into a test set and across validation set. The molecular descriptors were grouped into 18blocks, and within each we conducted a PCA to reduce thedimensionality in the test set and built a regression model to predict thefirst 4 PCs of the perceptual data. We then tested the model we derivedin the cross-validation set. We found that a linear combination of fewerthan 20 molecular features predicted the first PC of the perceptual space(r = 0.41, p < 0.001). These results underscore the primacy of valenceas an organization scheme for olfactory perception, and its importancein understanding the representation of molecular structures in olfactorycoding.175 Poster Multimodal, Chemosensory Measurement,Psychophysical, Clinical Olfactory, and TrigeminalHEDONIC GLMS: VALID COMPARISONS FOR FOODLIKING/DISLIKING ACROSS OBESITY, AGE, SEX AND PROPSTATUSBartoshuk L.M. 1 , Snyder D.J. 2 , Duffy V.B. 3 1 Center for Smell andTaste, Univ of Florida, Gainesville, FL; 2 Neuroscience, Yale Univ, NewHaven, CT; 3 Dietetics, Univ of Connecticut, Storrs, CTLabeled food preference scales like the Natick 9-point category scaleor the visual analogue scale (VAS) provide valid within subjectcomparisons. However, to provide valid across-group comparisons, thelabels on these scales must denote the same affective intensities to eachgroup. For example, a VAS might be labeled “zero” to “maximumliking of foods;” this assumes that “maximum liking of foods” denotesthe same intensity of liking to all. We used the hedonic general LabeledMagntitude Scale (hedonic gLMS) to demonstrate that this is often nottrue. Using this scale, subjects (N = 4299) rated liking/disliking for 26foods in the context of all affective experience rather than just affect forfoods. The maximum liking and maximum disliking were determinedfor each subject. These values were significantly correlated with bodymass index (BMI). As BMI rose, both the maximum liking andmaximum disliking rose; that is, the obese in this group of subjects livein an affectively more pleasant food world than do the non-obese. Forage, maximum liking did not rise, but maximum disliking did. For sex,women showed greater extremes than did men; that is, the maximumliking for women was higher and the maximum disliking was lower. ForPROP (propylthiouracil) status, supertasters showed greater extremesthan did nontasters. Since the boundaries of liking and disliking werenot constant over BMI, age, sex and PROP status, conventional labeledscales are invalid for comparisons of food liking/disliking across thesegroups. Funding: DC 000283.176 Poster Multimodal, Chemosensory Measurement,Psychophysical, Clinical Olfactory, and TrigeminalPSYCHOSOCIAL PREDICTORS OF 6-N-PROPYLTHIOURACIL RATINGS IN A GENERALPOPULATION SAMPLEMcAnally H.M. 1 , Poulton R. 1 , Hancox R. 1 , Prescott J. 2 , Welch D. 11 Preventive and Social Medicine, University of Otago, Dunedin, NewZealand; 2 Psychology, James Cook University, Cairns, Queensland,AustraliaThere is variability in rated sensitivity to the bitter compound, 6-n-Propylthiouracil (PROP). While polymorphisms of the TAS2R38 geneaccount for between 55-85% of the variance observed (Bufe et al 2005),it is likely that other factors also influence PROP ratings. In order toexamine some of these factors, the participants in the DunedinMultidisciplinary Health and Development Study rated PROP intensity.This study has followed a birth cohort of 1037 individuals since 1972.Ninety six percent (n = 972) of living participants were re-assessed in2004-2005 (aged 32) and their responses to 0.0032M of PROP weremeasured using the general Labelled Magnitude Scale (gLMS:Bartoshuk et al 2000). Participants were also asked to imagine thebrightest light ever seen and to rate this sensation on the gLMS. Thedata were analysed separately by sex. Factors predicting PROP ratingswere: childhood IQ scores (higher IQ predicting lower PROP rating),childhood SES scores (higher SES predicting lower PROP rating forwomen) and scores on the gLMS for the imagined brightest light(higher light rating predicting higher PROP rating) (final models: r 2 =0.168 for women, r 2 = 0.087 for men). Neither childhood IQ norchildhood SES predicted ratings for the imagined brightest light. Thesefinding indicate that psychosocial factors may account of some of thevariance in PROP ratings not explained by genetics. Funding wasprovided by the Health Research Council of New Zealand44