A novel two-step rating-based 'double-faced applicability' test. Part 2: Introducing a novel measure of affect magnitude (d'_A) for profiling consumers' product usage experience based on Signal Detection Theory

Kim, I.A.,Hopkinson, A.,van Hout, D.,Lee, H.S. Longman Scientific Technical ; Elsevier Science Pu 2017 Food quality and preference Vol.59 No.-

<P>To measure consumers' product usage experience throughout the various product usage stages, a novel two-step rating-based 'double-faced applicability' test has recently been proposed by Kim et al. (2017). In this method, a 'two-step' rating (forced-choice Yes/No questions followed by 3-point sureness ratings) and 'double-faced' descriptors (a pair of semantic-differential descriptors) are used for each attribute to improve the product discriminability by reducing consumers' response bias and variations. In this paper, we introduce a novel measure that can be computed from the data from the 'double-faced applicability' test to provide a new way to generate affective product usage experience profiles. The novel measure was a nonparametric estimate of affect magnitude, named as d-prime affect magnitude (d'A), computed by considering the response ratio of positivity to negativity as the ratio of signal to noise in the context of Signal Detection Theory (SDT). The advantage of using this new measure d'A was that it meaningfully reflected the consumers' affective product usage experience for each product independently (and how this affect valence changed through a usage process), yet it can still be used to compare between products. The practical application of using d'A was demonstrated in comparison to the more conventional SDT measure d'. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Sensory drivers of goso flavor in soymilk: Understanding a complex traditional Korean sensory attribute

Hwang, S.H.,Hong, J.H. Longman Scientific Technical ; Elsevier Science Pu 2013 Food quality and preference Vol.29 No.2

Goso flavor is a descriptive term in the Korean language that can be translated to ''nuttiness.'' However, its definition is not clearly identified yet. The usage of goso flavor in everyday life indicates its ambiguity and non-singularity. This study was conducted to identify the underlying sensory components of goso flavor perception, particularly in soymilk. Ten commercial soymilk samples were selected as a model system, and descriptive sensory profiles of these samples were obtained by 10 trained panelists. A total of 210 consumers rated goso flavor intensity and overall liking. The consumers were clustered according to their goso flavor rating, and then, the goso rating of each cluster was correlated to the sensory profile. Consumers were segmented into 3 clusters. Consumers in clusters 1 and 2 (n=15 and n=88, respectively) laid more emphasis on cooked soybean flavor, and consumers in cluster 3 (n=107) weighed sweetness, saltiness, and flavor of nuts when they rated goso. Clusters 1 and 2 used the goso term in a more analytical way, whereas cluster 3 associated goso with hedonic dimension.

Variants of A Not-A and 2AFC tests: Signal Detection Theory models

Hautus, M.J.,van Hout, D.,Lee, H.S. Longman Scientific Technical ; Elsevier Science Pu 2009 Food quality and preference Vol.20 No.3

Signal Detection Theory provides an approach to modelling difference test procedures that allows an estimate of the sensory difference between products to be obtained independently of the response bias and decision strategy used by the judge, and of the test procedure used to estimate that difference. The estimate of sensory difference obtained, d', is therefore much closer to a 'true' estimate of sensory difference than many other measures employed by sensory scientists. The methods used to generate models based on Signal Detection Theory are standard, and these methods are applied to the development of models for two test procedures (A Not-A and 2AFC) and their reminder equivalents (A Not-AR and 2AFCR). 2AFCR is procedurally identical to the duo-trio procedure with a constant reference; however, it is shown that there is more than one decision strategy available to the judge in this task.

Sensory difference tests: Overdispersion and warm-up

Angulo, O.,Lee, H.S.,O'Mahony, M. Longman Scientific Technical ; Elsevier Science Pu 2007 Food quality and preference Vol.18 No.2

For sensory difference tests, one way, but not the only way, of dealing with the problem of overdispersion is to use a beta-binomial analysis. Commonly, binomial statistical analyses are used for these methods and they assume that the sensitivity of the judges is uniform. However, judge sensitivity varies and this adds a problematical extra variance to the distribution. This is termed overdispersion and renders simple binomial analysis prone to Type I error. The distribution of sensitivity of the judges is described by a beta-distribution. The analysis, combining beta and binomial distributions, gives an index, gamma. This ranges from zero, for no overdispersion, to unity, for total overdispersion. A compact beta-distribution clustered around the mean of the binomial distribution, would add little extra variance and elicit minimum distortion of the binomial distribution, yielding a zero or near zero gamma value. A more scattered or even bimodal beta-distribution would have a substantial effect and yield a significant gamma value. One question that has been posed is whether some test methods are more prone to overdispersion than others. Yet, a consideration of the reasons for overdispersion would suggest that significant gamma values were more a result of obtaining a heterogenous sample of sensitive and insensitive judges by chance. To confirm this, 'less sensitive' and 'more sensitive' samples of judges performed 2-AFC and 3-AFC tests with resulting zero gamma values, indicating no overdispersion. However, when the less and more sensitive groups were combined, significant gamma values were obtained, indicating the presence of overdispersion. However, in a further experiment using 2-AFC tests, when the 'less sensitive' group had its sensitivity increased by a 'warm-up' procedure, combination with the 'more sensitive' group did not result in overdispersion.

Patterns of sweet liking in sucrose solutions and beverages

Kim, J.Y.,Prescott, J.,Kim, K.O. Longman Scientific Technical ; Elsevier Science Pu 2014 Food quality and preference Vol.36 No.-

While preferred levels of sweetness are known to differ across individuals, investigations of hedonic responses to sweetness across multiple concentrations in both model system and beverage are limited. The objective of this study was to classify people according to their preferred sweetness in sucrose solutions and beverages. The stimuli were water and flavored beverages, each containing five levels of sucrose. A total of 200 female subjects rated liking and intensity of sweetness for sucrose solutions, and they conducted paired preference tests using the Monell forced-choice, paired-comparison, tracking procedure. These tests were replicated for the beverage. These evaluations were conducted on two separate occasions, once while the subjects were hungry and once relatively sated. Hierarchical cluster analysis revealed three distinct clusters based on the hedonic ratings. Cluster 1 showed positive hedonic ratings with increased sucrose concentration in both systems. Cluster 2 showed positive ratings to sucrose increases in the beverage, but not in the sucrose solution. Cluster 3 showed an inverted-U shaped pattern. These patterns were confirmed by the result of the Monell test. Similar trends were observed when the subjects were asked to rate liking of chocolates and in ratings of preferences for commonly consumed sweet and savory food items.

Effects of interval length between tasting sessions and sweetener level on long-term acceptability of novel green tea drinks

Son, J.S.,Hong, J.H.,Kim, K.O. Longman Scientific Technical ; Elsevier Science Pu 2010 Food quality and preference Vol.21 No.8

The objective of this study was to investigate the effects of the interval length between sessions (1-day vs. 3-day), the sweetener level (Optimal (OP) vs. Low (LO)), and the number of stimuli (one vs. two) on long-term acceptability of a novel green tea drink. Two consumer groups (N=80) rated their liking of two drinks (OP and LO) while another 4 consumer groups (N=162) rated only one drink over 10 sessions at either 1-day or 3-day intervals. Repeated consumption led to an overall increase in liking of the novel drink even though the patterns of increase were different according to the sweetener level and the interval length. Higher sweetener level and shorter interval length might contribute to increase in liking score during the earlier sessions and stable liking during the later sessions for novel green tea drink.

Concurrent elicitation of hedonic and CATA/RATA responses with Chinese and Korean consumers: Hedonic bias is unlikely to occur

Jaeger, S.R.,Kim, K.O.,Lee, S.M.,Hunter, D.C.,Kam, K.,Chheang, S.L.,Jin, D.,Lee, P.Y.,Xia, Y.,Ares, G. Longman Scientific Technical ; Elsevier Science Pu 2017 Food quality and preference Vol.56 No.1

<P>In line with research in non-Western countries becoming main-stream, the need to validate existing research methods with consumers from these populations increase. The present research contributes hereto by quasi-replicating with Korean and Chinese consumers previous research concerning the risk of hedonic product responses being biased by co-elicitation of CATA/RATA questions for sensory product characterisation. Using consumers in several Western countries it was previously reported that bias could occur, but was unlikely to. Eleven studies involving 1000 East Asian consumers confirmed this conclusion. The studies were conducted with diversified populations and across multiple product categories. Across 7 studies, there were no instances where CATA co-elicitation was found to bias hedonic scores. However, in one of four studies where RATA responses were co-elicited bias did occur, and hedonic scores were, on average, lower when RATA responses were co-elicited. It is recommended that the research be replicated with consumers residing in their home countries and extended to other East and South-East Asian counties. (C) 2016 Elsevier Ltd. All rights reserved.</P>

''See me, feel me'': Effects of 3D-printed surface patterns on beverage evaluation

van Rompay, T.J.L.,Finger, F.,Saakes, D.,Fenko, A. Longman Scientific Technical ; Elsevier Science Pu 2017 Food quality and preference Vol.62 No.-

<P>Research shows that packaging appearance can have a strong impact on taste experience and product evaluation. However, so far research has mainly focused on how visual appearances may steer sensory impressions including smell and taste. Taking into account new (technological) developments which allow for consideration of a wide range of previously unexplored packaging factors, the research presented here investigates the impact of 3D-printed surface patterns on taste evaluations as a function of product type (a bitter tasting coffee versus a sweet tasting chocolate.drink) and verbal product claims (either stressing taste strength or taste softness). To this end, 3D-printed cups with angular and rounded surface patterns were manufactured and handed to shoppers participating in a taste session for a fictitious coffee or chocolate brand. Results show that an angular surface pattern increased perceived bitterness and taste intensity ratings, whereas a rounded surface pattern induced a sweeter taste evaluation and a less intense taste experience. Congruent pairings of drinks and tactile patterns resulted in more favorable outcomes. Finally, congruence was also found to be important with respect to taste descriptions, with verbal claims in line with surface pattern associations further enhancing product experience. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Affective same-different discrimination tests for assessing consumer discriminability between milks with subtle differences

Chae, J.E.,Lee, Y.M.,Lee, H.S. Longman Scientific Technical ; Elsevier Science Pu 2010 Food quality and preference Vol.21 No.4

Affective and analytical same-different discrimination tests for assessing the ability of consumers to discriminate between milks with subtle differences were designed by applying familiarization procedures to induce an affective/synthetic and analytical/synthetic perceptual strategy. The tests were then administered to 100 milk consumers and compared. In both same-different discriminations, consumers adopted a cognitive decision rule that used a β-strategy rather than a τ-strategy. Discrimination tests employing an affective/synthetic perceptual approach (which is the normal consumer perceptual process) resulted in higher discriminability than tests that employed an analytical/synthetic approach. Inter-individual differences in the consumer criteria (boundaries) used for same-different ratings were studied by examining the response distributions over the given response categories for the same pairs. According to the similarity of such response distributions, two different consumer segments were classified and their group discriminabilities differed significantly, with only the more sensitive group showing interactions between the affective/hedonic state and perceptual discriminability.

Comparison of performance in the A-Not A, 2-AFC, and same-different tests for the flavor discrimination of margarines: The effect of cognitive decision strategies

Lee, H.S.,van Hout, D.,Hautus, M.J. Longman Scientific Technical ; Elsevier Science Pu 2007 Food quality and preference Vol.18 No.6

The performance of three different discrimination tests (A-Not A, 2-AFC, same-different) was investigated to explore the effects of varying aspects of the test protocols, such as the familiarization procedure and retasting of the reference (A), during testing on discriminability and the cognitive decision strategy used in the tests, when discriminating between the two different margarines. Seven judges, who were not familiar with margarine products, each gave 24 ratings for each of six protocols, resulting in 168 ratings in the pooled data, and from which R-indices and d' estimates were calculated. When both test products were presented beforehand for familiarization, judges adopted the beta cognitive decision strategy. When only the reference (A) was presented to the judges beforehand for familiarization, and the reference (A) was retasted before the test product either by prescription or at will, the tau cognitive decision strategy was adopted. When the number of samples tasted within a test increased, discriminability was considerably decreased. Such differences between test protocols were explained in terms of the concept formation of the test products, carry-over and fatigue effects, and memory problems caused by longer time-intervals between tastings.