| An alternative method for assessing liking: Positional relative rating versus the 9-point hedonic scale | Journal of Sensory Studies 23 (2008) 284-292 Cordonnier, S.M. and Delwiche, J.F. An alternative rating method, known as positional relative rating (PRR), or rank rating, was compared with the traditional 9-point hedonic scale. Initially, category scale and line scale versions of PRR were investigated to see which of either was better at differentiating samples. Four lemonades were assessed in duplicate on both scales (category and line). Overall quality, sweetness intensity and sourness intensity were assessed in separate sessions by groups of ~50 consumers, depending on session. The category scale better differentiated samples than did the line scale for two of three attributes assessed, with differentiation being the same in the third. Subsequently, the overall liking of these same lemonades was assessed by 100 consumers on both the PRR category scale and the traditional 9-point hedonic scale. The differentiation of samples for both scales was equivalent, although mean values were somewhat lower with PRR. Request a reprint Return to Top | | Thurstonian probabilistic approaches to new food product development | Chapter 19 in Consumer-Led Food Product Development. (2007) H Macfie, Ed. Woodhead Publishing Limited, Cambridge. 456-470. Delwiche, J.F. This chapter aims to give the reader insight into probabilistic approaches to new product development. It begins with an explanation of probabilistic, or Thurstonian, modeling of perception, without which it is impossible to understand the utility of these approaches. The remainder of the chapter is devoted to specific models currently utilized in certain sectors for new product development. These models are described, and their applications, advantages, and disadvantages are discussed. Request a reprint Return to Top | | Impact of Flavor Attributes on Consumer Liking of Swiss Cheese | Journal of Dairy Science 91 (2008) 466–476 Liggett, R.E., Drake, M.A., and Delwiche, J.F. Although Swiss cheese is growing in popularity, no research has examined what flavor characteristics consumers desire in Swiss cheese, which was the main objective of this study. To this end, a large group of commercially available Swiss-type cheeses (10 domestic Swiss cheeses, 4 domestic Baby Swiss cheeses, and one imported Swiss Emmenthal) were assessed both by 12 trained panelists for flavor and feeling factors and by 101 consumers for overall liking. In addition, a separate panel of 24 consumers rated the same cheeses for dissimilarity. On the basis of liking ratings, the 101 consumers were segmented by cluster analysis into 2 groups: nondistinguishers (n = 40) and varying responders (n = 61). Partial least squares regression, a statistical modeling technique that relates 2 data sets (in this case, a set of descriptive analysis data and a set of consumer liking data), was used to determine which flavor attributes assessed by the trained panel were important variables in overall liking of the cheeses for the varying responders. The model explained 93% of the liking variance on 3 normally distributed components and had 49% predictability. Diacetyl, whey, milk fat, and umami were found to be drivers of liking, whereas cabbage, cooked, and vinegar were drivers of disliking. Nutty flavor was not particularly important to liking and it was present in only 2 of the cheeses. The dissimilarity ratings were combined with the liking ratings of both segments and analyzed by probabilistic multidimensional scaling. The ideals of each segment completely overlapped, with the variance of the varying responders being smaller than the variance of the nondistinguishers. This model indicated that the Baby Swiss cheeses were closer to the consumers’ ideals than were the other cheeses. Taken together, the 2 models suggest that the partial least squares regression failed to capture one or more attributes that contribute to consumer acceptance, although the descriptive analysis of flavor and feeling factors was able to account for 93% of the variance in the liking ratings. These findings indicate the flavor characteristics Swiss cheese producers should optimize, and minimize, to create cheeses that best match consumer desires. Request a reprint Return to Top | | Individual Differences in Perceived Bitterness Predict Liking of Sweeteners | Chemical Senses 32 (2007) 803–810 Kamerud, J.K. and Delwiche, J.F. Although recent molecular studies suggest that only one receptor and one signaling pathway are involved in the perception of sweetness, this seems to contradict everyday experience that people not only have different likes and dislikes of certain sweeteners but also perceive the sweeteners differently. One possible explanation is that variation in liking of sweeteners is due, in part, to variation across individuals in sensitivity to nonsweet tastes, such as bitterness, which are transduced by a variety of receptors. Fifty individuals were asked to rate intensities of several taste attributes of 10 sweeteners and to give hedonic assessments of each sweetener. Additionally, their sensitivity to 6-n-propyl-3-thiouracil (PROP) was determined. Results indicated that when matched for sweetness, the perception of bitterness and the sweetener compound were the 2 largest factors contributing to overall liking of a sweetener. Sensitivity to PROP did not contribute significantly to the model. Request a reprint Return to Top | | Relationship of Water Activity to Cone Crispness as Assessed by Positional Relative Rating | Journal of Sensory Studies 22 (2007) 687–694 Goerlitz, C.D. Harper, W.J., and Delwiche, J.F. The current industry standard for the assessment of ice cream cone crispness is a relatively complex instrumental measurement that more directly measures hardness than crispness. The objective of this research was to identify a simpler instrumental measure that corresponds to the consumer perception of crispness in ice cream cones. Uniform cone pieces were equilibrated to three different water activity (Aw) levels and 50 untrained judges rated crisp intensity of the pieces at each Aw level twice on a 10-point line scale using positional relative rating. Significant differences in perceived crispness between the three different Aw levels were found for two different cone types. No significant difference was found between replications. Correlation coefficients between perceived crispness and Aw were r = -0.999 (P < 0.01) for two different cones types. These findings suggest that Aw is a simple instrumental measure of crispness in sugar cones. Request a reprint Return to Top | | Consumer Perception of Cultured Yellow Perch (Perca flavescens) and Its Market Competitors | Journal of Food Science 71 (2006) S579–582 Delwiche, J.F., Liggett, R.E., and Wallat, G. Aquaculturists are concerned with performance of cultured yellow perch against its wild-caught market competitors. In this study, consumer perception of cultured yellow perch was compared to that of wild-caught walleye, ocean perch, and zander. In 2 experiments, species were ranked for preference, rated for liking, and rated for degree of difference from a reference (cultured perch). Results were analyzed using Friedman’s analysis of ranks, analysis of variance, and method of maximum likelihood. In Experiment 1 (n = 50), there was no significant difference in preference or liking, and all wild-caught species were significantly different from the reference. In Experiment 2 (n=68), the species were trimmed to the same thickness for a more fair comparison of these species. Cultured yellow perch was equally preferred to all species but was rated significantly higher than walleye in overall liking. In addition, ocean perch and walleye were found to be significantly different from cultured perch, while zander was not. Request a reprint Return to Top | | Effects of High Pressure Processing on the Microbiological and Physical Properties of Pasteurized Fluid Milk Products | Milchwissenschaft 61 (2006) 277–280 Adams, E.G., Delwiche, J.F., Harper, W.J. Increasing the shelf life of pasteurized milk using high pressure processing (HPP) and measurement of any changes in physical properties and flavour of the pasteurized milk during storage were investigated. Commercial samples of pasteurized 2% and chocolate milk were processed at 400-800 MPa for 10 or 5 min or 5 consecutive 1-min treatments at 25°C (±5°C). The samples were stored at 7.2°C and analysed on days 0, 10, 20 and 30 for psychrotrophic bacteria, brightness, particle size and viscosity. All HPP treatments extended the microbial shelf life of the milk samples. Initial psychrotrophic bacteria counts were low in the milk samples before HPP; thus, treatment pressure and time were not significant factors in the extension of microbial shelf life. The most significant physical change was a decrease in the brightness of the milk. In a sensory evaluation of the HPP treated milk samples, subjects could taste a significant difference between the older and fresher samples, and in the liking test subjects preferred the HPP day 1 and non-HPP day 1 samples over the HPP day 10 and HPP day 20 samples. Request a reprint Return to Top | | Consideration of Thurstonian Scaling of Rating Data | Food Quality and Preference 17 (2006) 556–561 Warnock, A.R., Shumaker, A.N., and Delwiche, J.F. In the analysis of sensory data, the use of parametric statistics, specifically analysis of variance (ANOVA), is standard. However, such parametric analyses often make assumptions that are not valid. Recent advances have made available an alternative analysis that does not make these assumptions, specifically Thurstonian Scaling of Ratings Data (SoR). This study compared these two methods of analyses on a single dataset. To further clarify the differences between analyses, assessments of a subset of the stimuli were also made in a triangle task. Findings indicate that the differences between ANOVA and SoR are minimal, with SoR tending to be slightly more conservative. Regardless of analyses used, triangle tests were found to be superior at differentiating the stimuli. The d' values determined using Thurstonian SoR did not agree with those determined with the triangle tests. Possible reasons for the discrepancy include boundary variance, actual strategy used during triangle tests, as well as other possible sources of variance. 2006 Elsevier Ltd. All rights reserved. Request a reprint Return to Top | Regional Variation in Sweet Suppression | Journal of Sensory Studies 21 (2006) 348–361 Warnock, A.R. and Delwiche, J.F. Differences in the sweet-blocking efficacy of 2-(4-methoxyphenoxy) propanoic acid (PMP) for different sweeteners (sucrose and aspartame) and for various exposure areas of the mouth were found. Twenty participants rated sweetener solutions with and without PMP for sweetness, sourness, saltiness, bitterness and umami for stimulation of anterior tongue, posterior tongue and whole-mouth areas. For sweetness ratings, suppression was significant for all stimulation areas. In the presence of PMP, stimulation of the posterior tongue yielded significantly higher sweetness ratings than stimulation of the anterior tongue for aspartame but not for sucrose. Sourness and bitterness ratings were significantly higher for anterior tongue than posterior tongue stimulations for aspartame but not for sucrose. The increases in sourness ratings in the presence of PMP were likely because of the sour taste PMP has at the concentration used. Results imply a difference between the front and the back of the tongue in the mechanisms involved in the perception of sweetness. Request a reprint Return to Top | Cross-Modal Summation in Taste and Smell | Journal of Sensory Studies 20 (2005) 512–525. Delwiche, J.F. and Heffelfinger, A.L. Subjects were simultaneously given subthreshold levels of taste and odor stimuli, delivered orally, for both a commonly paired and an uncommonly paired taste–odor combination. Results indicate cross-modal summation of subthreshold concentrations of both taste–odor pairs when the olfactory stimulus is delivered orally. Results of control studies suggest that the summation was indeed across modalities, and not due to the taste of the odor compound or the smell of the taste compounds. Furthermore, results indicate that regardless of taste–odor pair commonness, taste and smell can combine in a completely additive fashion (i.e., at threshold detectability when both stimuli are presented simultaneously at 50% threshold level) if the taste–odor pair is presented orally. In several instances, but not all, measured probabilities exceeded those predicted by probability summation, indicating that hyperadditive mixing often occurs, but there do seem to be individual differences. Cross-modal summation, regardless of taste–odor pair commonness, has broader implications for the development of foods, beverages and pharmaceuticals, especially in masking undesirable tastes and smells. Request a reprint Return to Top | Consumer liking and descriptive analysis of six varieties of organically grown edamame-type soybean | Food Quality and Preference 16 (2005) 651–658. Wszelaki, A.L., Delwiche, J.F., Walker, S.D., Liggett, R. E., Miller, S.A., and Kleinhenz, M. D. Six commercial varieties of organically grown edamame-type soybeans were compared using consumer testing and descriptive analysis. In the affective tests, 54 panelists rated pods and beans for appearance, and beans for aroma, taste, texture, aftertaste, and overall acceptability on a nine-point hedonic scale and willingness to buy on a nine-point category scale. The taste of ‘Sayamusume‘ was liked significantly better than all varieties except ‘Kenko’ and ‘Sapporo Midori’. ‘Kenko’ was also rated higher than ‘Sapporo Midori’, ‘Misono Green’, and ‘Early Hakucho’ for pod appearance. The texture of ‘Misono Green’ was liked less than that of all other varieties except ‘White Lion’. In the descriptive analysis, 10 trained panelists rated the beaniness, sweetness, nuttiness, and chewiness of the same six varieties. ‘Kenko’ was rated significantly sweeter than all other varieties except ‘Sapporo Midori’. ‘White Lion’ was rated as significantly lower in chewiness than all other varieties. Beaniness and nuttiness could not be consistently differentiated among varieties. The data suggest that consumer liking of bean taste varies, though subtly, among these six commercial edamame varieties and that preferences may differ between men and women. Results from descriptive analysis also suggest that panelists relied on texture (i.e., chewiness) and sweetness to differentiate edamame varieties. These results are particularly important in overall product quality management strategies as chewiness and sweetness may be influenced by production practices and harvest timing. Request a reprint Return to Top | Sensory Quality and Mineral and Glycoalkaloid Concentrations in Organically and Conventionally Grown Redskin Potatoes (Solanum tuberosum) | Journal of the Science of Food and Agriculture 85 (2005) 720–726 Wszelaki, A.L., Delwiche, J.F., Walker, S.D., Liggett, R.E., Scheerens, J.C., and Kleinhenz, M.D. Triangle tests were used to determine if panellists could distinguish (by tasting) cooked wedges of potatoes grown organically, either with (+) or without (−) compost, and conventionally. Mineral and glycoalkaloid analyses of tuber skin and flesh were also completed. When the skin remained on the potatoes, panellists detected differences between conventional potatoes and organic potatoes, regardless of soil treatment. However, they did not distinguish between organic treatments (± compost) when samples contained skin, or between any treatments if wedges were peeled prior to preparation and presentation. Glycoalkaloid levels tended to be higher in organic potatoes. In tuber skin and flesh, potassium, magnesium, phosphorus, sulfur and copper concentrations were also significantly higher in the organic treatments, while iron and manganese concentrations were higher in the skin of conventionally grown potatoes. Request a reprint Return to Top | The Beta-Binomial Model: Variability in Overdispersion Across Methods and Over Time | Journal of Sensory Studies 20 (2005) 48–61 Liggett, R.E. and Delwiche, J.F. The beta-binomial model accounts for variability between samples as well as variability between judges (overdispersion), making it possible to combine responses across judges and replications. Overdispersion (measured gamma) was examined in this 3-part study. (1) Groups of judges (n = 53– 59) performed two replications each of a paired comparison and paired preference. Results showed that extent of overdispersion could not be predicted from the method. (2) The stability of gamma across discrimination methods (2-alternative forced choice [2-AFC], 3-alternative forced choice [3- AFC], triangle and duo-trio) was also examined (n = 103). Results indicated that gamma was largely consistent across 2-AFC, 3-AFC and triangle tasks, but it was higher in the duo-trio task. (3) The stability of gamma over time was also investigated (n = 25). Results demonstrate that overdispersion varied over time with no clear pattern. In all cases, use of the beta-binomial model allowed responses across judges and replications to be combined, increasing the power achieved for a given panel size. Request a reprint Return to Top | Physical and Perceptual Interactions in the Perception of Cheese | Atti dei Convegni Scientifica di Cheese Art 2004 [Scientific Proceedings of Cheese Art 2004]: 400–406 Delwiche, J.F. When eating cheese, the sensations of taste, smell, touch, sight, and sometimes pain/irritation are stimulated. This paper reviews how all these sensations interact, impacting the perception of one another and resulting in a holistic, complex experience. Interactions between taste and smell, and interactions of the remaining sensations with taste and smell are explored, and practical implications of these interactions are considered. Request a reprint Return to Top | Workshop Summary: Data Analysis Workshop: Getting the Most Out of Just-about-Right Data | Food Quality and Preference 15 (2005) 891–899 Workshop presented at the Fifth Rose Marie Pangborn Sensory Science Symposium. Request a reprint Return to Top | Impact of Label Information on Consumer Assessment of Soy-enhanced Tomato Juice | Journal of Food Science 69 (2004) S376–S37 Goerlitz, C.D. and Delwiche, J.F. The impact of label information on the liking and closeness to ideal of tomato juice beverages was examined by having 100 judges assess 3 tomato juice beverages (Campbell’s tomato juice, V8 juice, and an experimental tomato juice enhanced with soy) either with or without labeling information. Judges rated overall liking of each product and then rated appropriateness of various attributes (saltiness, tomato flavor, thickness, texture, red color, orange color, and brown color) on 5-point just-right scales. Only half of the judges were presented with product related label information during evaluation. Overall liking scores were analyzed using repeated-measures ANOVA, whereas different attribute ratings were analyzed using Thurstonian Ideal Point modeling and Chi-square. Product associated label information did not significantly alter overall liking ratings (P > 0.05), although a significant difference in liking was found between products (P < 0.05). Similarly, the label information did not impact comparison of product attribute levels to ideal attribute levels. Both V8 and Campbell’s were significantly different from the ideal for 3 of the attributes (P < 0.05). For the soy-enhanced tomato juice, all 7 attributes were significantly different from the ideal (P < 0.05). In this instance, labeling information had no notable impact on assessments. Request a reprint Return to Top | Role of Sensory Analysis in Flavor Chemistry | Proceedings of the Ohio Grape-Wine Short Course (2004) Horticulture and Crop Science Department Series 739: 29–32 Delwiche, J.F. Information presented at the 2004 Ohio Grape-Wine Short course. Request a reprint Return to Top | Sensory Preference and Discrimination of Wild-Caught and Cultured Yellow Perch (Perca flavescens) | Journal of Food Science 69 (2004) SNQ144–SNQ147 Delwiche, J.F. and Liggett, R.E. Department of Food Science and Technology, The Ohio State University Wild-caught and cultured yellow perch (Perca flavescens) were compared for overall difference and preference. Judges (n = 52) completed 2 replications each of both a paired preference and a triangle test. Results were analyzed using the β-binomial model. Findings indicate that samples were significantly different from each other (P = 0.0001) but there was no significant preference for either sample (P = 0.1167). For both tests, overdispersion, or panelist variability, was very low, indicating judges were acting similarly and the binomial model better fit the data. Judges’ comments were contradictory and inconsistent, making it impossible to determine the exact nature of the difference. Request a reprint Return to Top | Triangle Tests Indicate that Irrigation Timing Affects Fresh Cabbage Sensory Quality | Food Quality and Preference 15 (2004) 471–476 Radovich, T.J.K., Kleinhenz, M.D., Delwiche, J.F., and Liggett, R.E. A replicated triangle test was employed to determine if judges could distinguish, by tasting, between shredded samples of fresh cabbage drip-irrigated during different periods of plant development. Irrigation was provided either: (1) throughout plant development (no stress, NS), (2) during frame development only (head stress, HS), or (3) during head development only (frame stress, FS). Control plants received no irrigation for the duration of plant development (frame and head stress, FHS). In a total of three sessions, 14 judges evaluated two replications each of the six possible treatment comparisons in triangle tests. Results were analyzed using the beta-binomial model. Judges detected differences (α = 0.05) between cabbage from NS plots and cabbage from the two plots that received no irrigation during head development (HS, FHS), as well as between heads from FS and FHS plots. Physical traits of cabbage heads (e.g. weight, mean diameter, shape) at harvest were also affected by irrigation treatment. This is the first report to suggest that the timing of irrigation relative to crop development may influence the sensory characteristics of fresh cabbage. The data also suggest that cabbage head physical traits may respond more frequently to irrigation than cabbage sensory attributes. Request a reprint Return to Top | The Impact of Perceptual Interactions of Perceived Flavor | Food Quality and Preference 15 (2004) 137–146 Delwiche, J.F. Ohio State University, Department of Food Science and Technology 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. Request a reprint Return to Top | Edited Book | K. Deibler and J. Delwiche (2003) Handbook of Flavor Characterization: Sensory Analysis, Chemistry, and Physiology. Marcel Dekker. View book description and review Return to Top | Effects of the Form of Glasses on the Perception of Wines: A Blinded Study in Untrained Subjects | Appetite 41 (2003) 197–202 Hummel, T., Delwiche, J.F., Schmidt, C., and Hüttenbrink, K.-B. Many wine connoisseur claim that the glass shape has a direct impact on wine aroma. This hypothesis was investigated in healthy volunteers (85 m, 96 f; age 19–73 years); 89 subjects received red wine, 92 subjects white wine. Subjects compared three glasses with a white wine and three glasses with a red. Glasses were of different shape but of the same height and of comparable opening diameter. All glasses had elegant stems; two glasses of ‘tulip’ and ‘beaker’-like shapes were used in sessions with red and white wines. Different bulbous glasses were used in either red or white wine sessions. Subjects were blinded whether they received one or more wines. Intensity, hedonic tone, and quality of the wines were rated repeatedly before and after drinking. Ratings of wine odors from different glasses were influenced by glass shape. Importantly, this appeared not to relate to the esthetic impression the glasses made. Thus, the present data indicate that the shape of glasses seems to influence the perception of wine odors. Request a reprint Return to Top | Attributes Believed to Impact Flavor: An Opinion Survey | Journal of Sensory Studies 18 (2003) 347–352 Delwiche, J. F. The definition of “flavor” is a term that appears to vary from one area to the next. A survey was conducted on 140 individuals in various areas of specialization (agriculture, food science, sensory evaluation, and the chemical senses) to see what sensations are thought to be involved in “flavor,” as well as whether there were any differences in definitions across groups. The results demonstrate that while a fairly stable definition of the term does exist, there is some difference in what different groups of expertise mean when they refer to “flavor.” Request a reprint Return to Top | Impact of Color on Perceived Wine Flavor | Foods and Food Ingredients: Journal of Japan 208 (2003) 349–352 Delwiche, J.F. Ohio State University, Department of Food Science and Technology While taste and smell are important aspects of flavor, multiple lines of evidence indicate that color can alter the perception of taste, smell and flavor. While this has been demonstrated under laboratory conditions many times with model solutions, only recently was it shown that the phenomenon also occurs under a more casual setting with a complex stimulus such as wine. Request a reprint Return to Top | Sensory Preference, Coating Evenness, Dustiness, and Transfer Efficiency of Electrostatically Coated Potato Chips | Journal of Food Science 68 (2003) 1542–1547 Ratanatriwong, P., Barringer, S.A., and Delwiche, J. Barbeque, sour cream and onion, salt and vinegar, nacho cheese, and salsa seasonings were applied to potato chips at 0 and 25 kV. Sensory evaluation determined that electrostatically coated chips had better coating uniformity and were significantly preferred to nonelectrostatically coated samples. Electrostatic coating was also more even as measured by colorimetry. Particle size and evenness of coating did not significantly affect perceived flavor intensity. Electrostatic coating significantly increased transfer efficiency and decreased dust over nonelectrostatic coating. Particle size and flowability can be used to predict transfer efficiency and dustiness. Chargeability was also important for electrostatic transfer efficiency. Particle size was the most important factor overall. Request a reprint Return to Top | Clustering Bitter Compounds via Individual Sensitivity Differences | Chapter 6 in Chemistry of Taste: Mechanisms, Behaviors and Mimics. Eds. Peter Given and Dulce Paredes. ACS Symposium series 825. Washington, D.C.: American Chemical Society. (2002):65–77 Delwiche, J.F., Buletic, Z., and Breslin, P.A.S. Although it had been well documented that people varied widely in their sensitivities to bitter compounds, the intercorrelation of these sensitivities remained unknown. By clustering bitter compounds representative of different chemical classes as a function of individual sensitivities, it was possible to infer the number and variety of potential bitterness transduction systems involved in bitter perception. Results indicated that bitter compounds could be grouped into two general groups, neither of which contains PROP (n-propylthiouracil). There are also subjects who possess diminished absolute sensitivity to bitter stimuli, but do not differ in their relative sensitivities to these compounds. Request a reprint Return to Top | Influence of Glass Shape on the Perception of Wine Aroma | Journal of Sensory Studies 17 (2002)19–28 Delwiche, J.F., and Pelchat, M.L. Differences in the physical shape of glasses could potentially influence proportions of aromatic compounds trapped in the headspace of a wine glass, altering the perception of a wine. Blindfolded, naïve subjects assessed the aroma of a California Cabernet Sauvignon presented in 4 different glasses. Two of these were from a speciality line of crystal wine glasses, one designed for Chardonnay, the other for Bordeaux/Cabernet Sauvignon. A restaurant-style wine glass and a leaded crystal goblet were the remaining vessels used. The non-expert judges assessed wine aroma for total intensity, fruitiness, vinegariness, oakiness, and mustiness, as well as liking. The only significant difference found in the aroma intensity ratings was for the Bordeaux glass, which was rated as having a significantly lower total intensity than the other three glasses. However, several significant correlations were found between the attribute intensity ratings and physical characteristics of the glasses. This suggests that the glass does have a limited, but subtle, impact upon the olfactory experience of wines. Request a reprint Return to Top | The Impact of Wood Ice Cream Sticks' Origin on the Aroma of Exposed Ice Cream Mixes | Journal of Dairy Science 85 (2002) 355–359 Jiamyangyuen, S., Delwiche, J.F., and Harper, W.J. The effect of volatile compounds in white birch sticks obtained from four different geographical locations on the aroma of ice cream mix was investigated. Sensory evaluation, (specifically, a series of warmed-up paired comparisons) was conducted on stick-exposed ice cream mixes to see if aroma differences in those mixes could be detected. Batches of ice cream mix were exposed to the sticks and aged for 6 days at 4º C and then assessed by the panelists by pairwise comparison. Findings suggest that differences in aroma of mixes that have been exposed to white birch sticks from four different geographical origins can be distinguished perceptually. Request a reprint Return to Top | Relationship of Papillae and Intensity of Quinine and PROP Within and Between Individuals | Physiology & Behavior 4 (2001) 1–9 Delwiche, J.F., Buletic, Z., and Breslin, P.A.S. 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. Request a reprint Return to Top | Covariation in Individuals Sensitivities to Bitter Compounds: Evidence Supporting Multiple Receptor/Transduction Mechanisms | Perception & Psychophysics 63 (2001) 761–776
Delwiche, J.F., Buletic, Z., and Breslin, P.A.
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, and n-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. Request a reprint Return to Top | Der Genuss von Rotwein wird durch die Form des Glases beeinflusst
[The Aroma of Red Wine is Modified by the Form of the Wine Glass] | Larngo-Rhino-Otologie 80 (2001) 96–100
Hüttenbrink, K.-B., Schmidt, C., Delwiche, J.F., and Hummel, T.
[Background: It is frequently claimed that the glass shape has a direct impact on wine aroma. Methods, Patients: Healthy volunteers (43 m, 46 f, age 19-60 years) tried 3 glasses. Three glasses of different shape but of the same height and of comparable opening diameter were used. Glasses were "tulip"-like, "beaker"-like and "egg"-like shapes. Intensity, hedonic tone, and quality of a red wine were rated before and after drinking. Results: Both intensity and hedonic ratings of wines from different glasses were influenced by glass shape. Glass shape also influenced the complexity of wine odors. This appeared not to be related to the esthetic impression the glasses made. Conclusions: The present data indicate that egg-shaped glasses, compared to "tulip" or "beaker" glasses, appear to produce higher intensity and higher complexity of wine odors. This may relate to the trapping of odors in egg-shaped glasses.] Request a reprint Return to Top | Selective Removal of a Target Stimulus Localized by Taste in Humans | Chemical Senses 25 (2000) 181–187
Delwiche, J.F., Lera, M.F., and Breslin, P.A.
Recent studies have shown that people can localize a punctate gustatory stimulus on the lingual epithelium in the absence of discriminative tactile cues. The present studies examined the human ability to localize taste sensations on the tongue and to use this information to remove selectively a target stimulus (a flavored, 1 cm(3) gelatin cube) from the mouth when presented with non-target distractors that vary in number and taste. Findings indicate that humans are capable of localizing and removing either an aversive or an appetitive gustatory target from a field of tactile distractors via taste sensations alone, although this ability diminishes as the number of distractors increases (implicating serial searches, rather than parallel). In addition, humans can localize and selectively remove a target taste in the presence of distractors of another distinct taste quality. Under these conditions performance is either unaffected or reduced, which indicates that contrast with the distinct taste of the distractors does not enhance performance. Humans also are capable of removing a nearly tasteless cube from a field of flavored distractors, but this is clearly a more difficult task, suggesting that 'tactile capture' of taste occurs for the tasteless target cube and interferes with the localization of taste. Finally, perceived suprathreshold stimulus intensity did not seem to be related to the ability to localize and remove a target stimulus via taste sensations and failed to account for variations in performance across individuals. Request a reprint Return to Top | Anion Size of Sodium Salts and Simple Taste Reaction Times | Physiology & Behavior 66 (1999) 27–32
Delwiche, J.F., Halpern, B.P., and Desimone, J.A.
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.
Request a reprint Return to Top | Are There 'Basic' Tastes? | Trends in Food Science and Technology 7 (1996) 411–415
Delwiche, J.
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. Request a reprint Return to Top
| A Comparison of Tip of the Tongue and Sip and Spit Screening Procedures | Food Quality and Preference 7 (1996) 293–97
Delwiche, J., Halpern, B.P., and Lee, M.Y.
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 mm2 of the anterodorsal tongue. Therefore, a tip of the tongue screening method was developed and compared to sip & spit screening. It was found that subject performance on the tip of the tongue screening task did not predict performance on the sip & 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. Request a reprint Return to Top
| Changes in Secreted Salivary Sodium are Sufficient to Alter Salt Taste Sensitivity: Use of Signal Detection Measures with Continuous Monitoring of the Oral Environment | Physiology & Behavior 59 (1996) 605–611
Delwiche, J. and O'Mahony, M.
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. Request a reprint Return to Top
| Flavour Discrimination: an Extension of Thurstonian 'Paradoxes' to the Tetrad Method | Food Quality and Preference 7 (1996) 1–5
Delwiche, J. and O'Mahony, M.
The paradox of discriminatory nondiscriminators, 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. Request a reprint Return to Top
| Focused Difference Testing for the Assessment of Differences Between Orange Juices Made from Orange Concentrate | Journal of Sensory Studies 1993; Vol. 8:43–67
Barbary, O., Nonaka, R., Delwiche, J., Chan, J., and O'Mahony, M.
Focused difference testing was applied to two orange juices prepared from frozen concentrate. Differences were noted between the juices for darkness of color, visual appearance of pulpiness, resistance to tongue movement, flavor by mouth, odor, overall taste and taste other than sweetness. The logic and approach of focused difference testing is discussed and contrasted with other sensory analytical techniques. Request a reprint Return to Top |
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