Jeannine F. Delwiche

The impact of perceptual interactions on perceived flavor

Abstract When eating or drinking, the individual experiences a multitude of sensations, including taste, smell, touch, temperature, sight, sound, and sometimes pain/irritation. This multi-faceted sensory experience is the underpinning of perceived flavor, although certainly some sensations contribute more than others. This paper reviews how all these sensations interact, both on a perceptual and a physical level, and discusses the resulting impact each has on flavor ratings. Interactions between taste and smell, and interactions of the remaining sensations will be discussed. Finally, practical implications of these interactions for sensory evaluation are discussed.

Covariation in individuals' sensitivities to bitter compounds: evidence supporting multiple receptor/transduction mechanisms.

People vary widely in their sensitivities to bitter compounds, but the intercorrelation of these sensitivities is unknown. Our goal was to investigate correlations as a function of individual sensitivities to several bitter compounds representative of different chemical classes and, from these correlations, infer the number and variety of potential bitterness transduction systems for these compounds. Twenty-six subjects rated and ranked quinine HCl, caffeine, (−)-epicatechin, tetralone, L-phenylalanine, L-tryptophan, magnesium sulfate, urea, sucrose octaacetate (SOA), denatonium benzoate, andn-propylthiouracil (PROP) for bitterness. By examining individual differences, ratings and rankings could be grouped into two general clusters—urea/phenylalanine/tryptophan/epicatechin, and quinine/caffeine/SOA/denatonium benzoate/tetralone/magnesium sulfate—none of which contained PROP. When subjects were grouped into the extremes of sensitivity to PROP, a significant difference was found in the bitterness ratings, but not in the rankings. Therefore, there are also subjects who possess diminished absolute sensitivity to bitter stimuli but do not differ from other subjects in their relative sensitivities to these compounds.

Relationship of papillae number to bitter intensity of quinine and PROP within and between individuals.

Subjects were asked to assess the bitterness of one 6-n-propyl-2-thiouracil (PROP) and two quinine HCl (QHCl) concentrations presented via filter papers of varying sizes. The number of taste papillae stimulated by these filter papers was counted in each individual. Whole mouth sensitivity to PROP was determined in a separate session. In support of other demonstrations of spatial summation, these data indicated that perceived bitterness intensity increased as a function of area of stimulation within subjects. Between subjects, there was a significant trend for the perceived bitterness of PROP to increase with the lingual density of fungiform papillae, although this trend was highly variable and was only demonstrable among those who showed at least moderate sensitivity to PROP. On the other hand, the number of stimulated fungiform papillae failed to account for individual differences in perceived bitterness of QHCl.

Changes in secreted salivary sodium are sufficient to alter salt taste sensitivity: use of signal detection measures with continuous monitoring of the oral environment.

A signal detection measure of NaCl taste sensitivity was developed with continuous monitoring of the Na+ concentration of the oral environment. Taste sensitivity was reduced when saliva was stimulated by chewing to secrete with elevated Na+ levels. Monitoring of the oral environment for Na+ allowed a computation of physical signal strengths for NaCl and water stimuli; changes in these strengths, brought about by variations in secreted salivary sodium, furnish an explanation for alterations in NaCl taste sensitivity.

Are there 'basic' tastes ?

Abstract Although it is widely accepted that there are only four tastes (or five, including umami), this idea lacks logical rigor, empirical confirmation and functional utility in either theoretical or applied domains. Possible definitions of ‘basic tastes’ and alternatives to the ‘four basic tastes’ hypothesis are considered. Research limitations that arise as a result of the acceptance of the four basic tastes hypothesis are discussed, and an example of how this hypothesis can distort data is given.

Flavour discrimination: An extension of thurstonian ‘Paradoxes’ to the tetrad method

Abstract The paradox of discriminatory nondiscrinators, whereby subjects discriminate stimuli better in a triadic test when the instructions specify the attribute that is changing, was confirmed for a multisensory food stimulus, chocolate pudding. Further untested predictions were confirmed regarding attribute specification for tetradic tests. As predicted, tetrads were not like triads; specifying the attribute did not elicit better discrimination.

You eat with your eyes first.

While the senses of taste, smell, and vision are distinct, visual stimuli have been shown to alter the perception of taste, smell, and flavor. Color may be the most obvious visual cue, but expectations through learned associations are set by other visual cues as well, including gloss, evenness, and shape. These expectations exert cognitive top-down influences that can and sometimes do alter assessments of taste and flavor.

Handbook of flavor characterization : sensory analysis, chemistry, and physiology

Sensory and physiology of flavour: methods, approaches and caveats for functionally evaluating olfaction and chemesthesis - Charles J. Wysocki and Paul Wise sensory analysis and analytical flavour chemistry - some missing links - Susan E. Ebeler when are oral cavity odorants available for retronasal olfaction? - Bruce P. Halpern similarity and diversity in flavour perception - Terry E. Acree, Kathryn D. Deibler and Katherine M. Kittel. Relating physical measures with flavour perception: difficulty in measuring what matters - context effects - Bonnie M. King, Paul Arents and C.A.A. Duineveld measuring the sensory impact of flavour mixtures using controlled delivery - David J. Cook, Jim M. Davidson, Rob S.T. Linforth and Andrew J. Taylor nosespace analysis with proton-transfer-reaction mass spectrometry - intra- and interpersonal variability - D.D. Roberts, P. Pollien, C. Yeretzian and C. Lindinger correlation between sensory time-intensity and SPME analysis of fruity flavour in model food emulsions - M. Fabre, E. Guichard, V. Aubry and A. Hugi. Gas chromotography - olfactometry: new flavour compounds from orange essence oil - Sabine Widder, Marcus Eggers, Jan Looft, Tobias V ssing and Wilhelm Pickenhagen heat-induced changes in aroma components of holy basil (ocimum sanctum L.) - Sompoche Pojjanapimol, Siree Chaiseri and Keith R. Cadwallader interactions of selected flavour compounds with selected dairy products - Klaus Gassenmeier challenges in analyzing difficult flavours - Willi Grab nose to text - voice recognition software for GC-O - Philippe Mottay. Comparisons of techniques, methods and models: headspace sampling - a critical part in evaluating true gas phase concentrations - Gerhard N. Zehentbauer, Cindy I. Eddy, Pete A. Rodriguez, Christa S. Pelfrey and Jianjun Li meat aroma analysis - problems and solutions - J. Stephen Elmore, Donald S. Mottram and Andrew T. Dodson analysis of flavour compounds from microwave popcorn using supercritical fluid CO2 followed by dynamic/static headspace techniques - Ramachandran Rengarajan and Larry M. Seitz representative sampling of volatile flavour compounds - the model mouth combined with gas chromatography and direct mass spectrometry - Saskia van Ruth, Mike Geary, Katja Buhr and Conor M. Delahunty. Real time analaysis of flavour components: on-line monitoring of the Maillard reaction - Lalitha R. Sivasundaram, Imad A. Farhat and Andrew J. Taylor optimizing release of flavour in purge and trap analysis using humidified purge gas and inverse gas chromatography - James Castellano and Nicholas H. Snow novel mass spectrometric techniques for monitoring aroma volatiles - Rob S.T. Linforth and Andrew J. Taylor identification of volatile compounds using combined GC-EI-API-MS - Andrew J. Taylor, L. Sivasundaram, R.S.T. Linforth and S. Surawang. (Part contents).

Anion size of sodium salts and simple taste reaction times.

Simple taste reaction times (RT) and taste intensities were measured in adult humans for 100-mM aqueous solutions of sodium chloride, acetate, glutamate, ascorbate, and gluconate flowed over the anterodorsal tongue with a closed liquid delivery system. Results from 12 subjects showed a significant increase in RT with molecular weight of the tastant, and a correlation of 0.941 between RT and the square roots of anionic weights. A multiple regression analysis controlling for perceived taste intensity indicated that RT increased linearly with the square root of the anionic weight. These findings support a model that includes both the permeability of ions through the tight junctions between the taste receptor cells of fungiform papillae taste buds and the effects of ions at apical portions of the receptor cells. They also suggest that gustatory transduction of sodium salts in humans normally involves intercellular spaces of taste buds as part of the functional sensory structures, in addition to individual taste receptor cells.

A comparison of tip of the tongue and sip and spit screening procedures

Abstract Sip and spit stimulus delivery is a common technique in taste research for both screening subjects and for primary data collection, but when stimulation of limited regions of the mouth is required, other stimulus delivery methods are necessary. The appropriate screening method for limited tongue area gustatory studies is unclear. For data collection the authors routinely use a closed stimulus delivery system to flow liquids over ~40 mm 2 of the anterodorsal tongue. Therefore, a tip of the tongue screening method was developed and compared to sip and spit screening. It was found that subject performance on the tip of the tongue screening task did not predict performance on the sip and spit screening task, and vice versa. Furthermore, many subjects reliably described and distinguished between low concentration sucrose, HCl, NaCl and quinine sulfate solutions restricted to the tip of the tongue.