Showing papers in "Journal of Sensory Studies in 2004"

The role of auditory cues in modulating the perceived crispness and staleness of potato chips

Abstract: We investigated whether the perception of the crispness and staleness of potato chips can be affected by modifying the sounds produced during the biting action. Participants in our study bit into potato chips with their front teeth while rating either their crispness or freshness using a computer-based visual analog scale. The results demonstrate that the perception of both the crispness and staleness was systematically altered by varying the loudness and/or frequency composition of the auditory feedback elicited during the biting action. The potato chips were perceived as being both crisper and fresher when either the overall sound level was increased, or when just the high frequency sounds (in the range of 2 kHz-20 kHz) were selectively amplified. These results highlight the significant role that auditory cues can play in modulating the perception and evaluation of foodstuffs (despite the fact that consumers are often unaware of the influence of such auditory cues). The paradigm reported here also provides a novel empiric methodology for assessing such multisensory contributions to food perception. © Copyright 2004, Blackwell Publishing.

Training effects on performance of descriptive panelists

Abstract: The amount of training necessary to adequately “train” a descriptive panel is a matter of contention. The objectives of this research were to compare the performance of descriptive panelists after short-term (4 h), moderate (60 h) and extensive training (120 h). Seven screened panelists were chosen to evaluate three commercial tomato pasta sauces after each training period. Panelist performance improved with increased training. Sample differences were observed in all texture attributes and some flavor attributes, even after the shortest training time (4 h). However, more differences were found with at least 60 h of product training. After 120 h of training, product differences for all texture attributes and most of the flavor attributes studied could be ascertained by the trained panelists. These results suggested that only limited training may be necessary to find differences among products for many texture attributes and some flavor attributes. However, extensive training may be required to reduce variation among panelists and increase the discriminant abilities of panelists.

Sensory characteristics of chemical compounds potentially associated with beany aroma in foods

Abstract: Smoky aroma can either enhance sensory quality of foods (e.g. meat or cheese) or be detrimental to the product (e.g. raw or processed grains and grain products). Twenty-one chemical compounds suggested from the literature or from gas chromatographic headspace analysis of raw grains as potentially responsible for smoky aroma were studied. Five highly trianed sensory panelists smelled each compound dissolved in propylene glycol (if soluble) at a dilution of 5,000 to 20,000 ppm depending on the aroma strength of the compound. Approximately 60% of the compounds were found to have some smoke character, although the intensity of smokiness often was low. Some compounds such as benzyl disulfide and 3,7-dimethyl-6-octenoic acid were predominately smoky, but had other aroma characteristics that were lower in intensity. Most compounds had other aroma characteristics that were more intense than smoke (e.g. 2-ethylpyridine) and some compounds, such as 1-methylpyrrole were not smoky at all.

Research note numerical scale-point locations for constructing the lam (labeled affective magnitude) scale

Abstract: In a recent paper, we described the development and application of a labeled affective magnitude (LAM) scale for assessing liking/disliking (Schutz and Cardello 2001). Here we present the exact numerical scale-point locations corresponding to the verbal labels of the scale, so that investigators can easily construct the LAM scale for use with either paper or computer-based ballots.

Common and specific effects of fine fragrances on the mood of women

Abstract: The effect of three pleasant fine women's fragrances on the mood of women was assessed. The three fragrances had similar hedonic values but different sensory characteristics. The fragrances elicited nonspecific effects on mood. All three fragrances’ impact on mood was influenced by initial mood and lasted up to three hours, i.e., as long as the scent was still noticeable. Trends revealed that all three fragrances decreased negative affect and increased vigor. Also, independent of their hedonic value, the three fragrances elicited specific mood patterns. With the “woody citrus coniferous” scent, respondents experienced higher hostility and tension. The “floral chypre citrus” fragrance decreased anger and confusion. The “floral woody” scent had the lowest Total Mood Disturbance score and lowered depression, tension and confusion.

Performance comparison between trained assessors and wine experts using specific sensory attributes

Abstract: The profile of nine samples of Chardonnay wines was used to compare the performance of an expert panel and a trained descriptive panel using a common sensory terminology. Each panel (expert and trained) consisted of eight members, and the descriptors used by both groups were generated by the trained assessors. Thirteen out of 17 attributes evaluated turned out significant for wine discrimination among experts, and seven out of 17 for trained subjects. The trained panel reached a higher level of consensus, while the experts were more discriminative among attributes. The principal components analysis (PCA) corresponding to the expert group explained 88.68% of the total variance among the samples of the first two components. A third component was needed for the group of trained assessors (87.66% variance). The PCA showed the same wine grouping for both panels, indicating that differences were perceived in a similar way, despite that the sensory dimensions of these differences was not the same in all the cases.

A comparison of category and line scales under various experimental protocols

Abstract: Judges were required to rate the total intensity of NaCl solutions and the sweetness of orange flavored beverages using a variety of unstructured category and line scales. Discrimination errors were noted for each type of scale. No strong differences were observed in discrimination between category and line scales although a 20-point category scale incurred fewer discrimination errors than 9-point category and line scales. Allowing judges to retaste stimuli and review and modify their scores reduced discrimination errors.

Mind‐sets of the wine consumer

Abstract: This paper presents the results from a study of consumer reactions to different attributes of red and white wine, with stimuli presented in the form of small, experimentally designed, test concepts (conjoint measurement). The results show that possibly four consumer mind-sets exist, with each mind-set comprising a different set of communication drivers for concept acceptance. Most subjects fit into one of three key categories; “Classics” (who want their wines to be traditional), “Imaginers” (who want to get into the drinking experience through knowing details about their wines) or “Elaborates” (who want their wines to produce many sensations and flavors). A fourth group (No Frills), were interested in simple and safe wines without any detail of flavor or origin. This segment was found in the red wine study, but not in the white wine study.

Evaluation of the character impact odorants in skim milk powder by sensory studies on model mixtures

Abstract: The objective of this study was to verify key aroma-active compounds responsible for reconstituted fresh skim milk powder (SMP) aroma using threshold analysis, odor activity values, and model systems. Twelve odor-active compounds of SMP and one odor-active compound from fluid milk were selected based on flavor dilution factors from gas chromatography-olfactometry. Thresholds for the 13 odor-active compounds were identified using five-set ascending forced choice threshold analysis in odor-free water and fluid skim milk. Model systems were prepared using rehydrated milk retentate (RMR). The aroma of each model was evaluated by descriptive sensory analysis and by difference-from-control testing using a trained panel. The aroma of reconstituted fresh SMP and liquid skim milk were used as controls. Models containing a mixture of twelve of the thirteen chemicals had the most similar odor characteristics to rehydrated SMP aroma (9.0/10) indicating that these compounds constitute the character impact odorants of rehydrated fresh SMP.

Sensory shelf-life estimation of alfajor by survival analysis

Abstract: Survival analysis methodology was used to estimate the shelf life of alfajor (a chocolate-coated individually wrapped cake) at 20 and 35C by using results obtained from consumers when asked if they would accept or reject samples with different storage times. Sensory acceptability (measured by consumers), off-flavor (measured by a trained panel) and moisture content were linearly related to time. These correlations were used to estimate values at the shelf-life times calculated for 25 and 50% rejection probability. Survival analysis provided the following shelf-life estimation: 74 days at 20C and 33 days at 35C for a 25% of rejection, 87 days at 20C and 39 days at 35C for a 50% of rejection. An alfajor stored at 20C having an acceptability value below 4.9 (1–9 hedonic scale) and off-flavor intensity above 5.3 (0–10 scale) would be rejected by 25% of the consumers. Chemical data were not good shelf-life predictors.

Selection of an astringency reference standard for the sensory evaluation of black tea

Abstract: Astringent and bitter sensations are characteristic sensory qualities of black tea. Three different classes of potential astringent reference standards (two concentrations each of alum and tannic acid and three fruit juices) were evaluated in this study. The perceived astringency, bitterness and sourness of each were profiled using computerized time-intensity and compared with the astringent intensity of a standardized brew of black tea. The differences in temporal profiles of potential reference standards across taste attributes were evident and intensity ratings were found to be dependent upon the stimulus and its concentration. Both concentrations of tannic acid were evaluated as the highest in perceived bitterness. For the juices, a strong sour taste was perceived in addition to astringency. It was concluded that the best reference standard for the astringency of black tea is a solution of 0.7 g/L alum as it is low in perceived bitterness and sourness.

Freshness in oral care: attributes and time‐dependency of a multidimensional, dynamic concept

Abstract: This article describes an exploration of the concept of ‘oral freshness’ for as far as it is important in oral care. It intends to consider the most important mouth sensations and cognitive connotations, including (but not restricted to) the well-known effect of menthol in toothpaste. Two aspects were given attention: (1) The attributes that together form the concept of oral freshness were investigated using a ‘personal construct approach’(Kelly 1955). This method consists of unbiased, structured interviews with subjects, and ultimately yields attribute dimensions that the subjects have in common. (2) The intensity of the freshness sensation over time was investigated using the Time-Intensity method. Subjects gave repeated freshness judgments every few seconds after the intake of a freshness-related stimulus, and continued to do so after the stimulus had left their mouth. In addition we asked for ‘overall’ freshness judgments directly after the TI-measurements and after 2 months. The results confirm that ‘oral freshness’ is a complex concept. We identified 6 attributes, some of which were perceptual/physiological and some cognitive in nature: ‘water’-ness, cool/cold-ness, taste (menthol-ness), clean-ness, smell, energy (texture and touch, e.g., bubbles). Different persons will generally give different importance weights to each of these 6 attributes. Time-intensity measurements show that temperature, menthol-content and, to some extent, the presence of bubbles (energy) influence the momentous sensation of freshness. It appears, however, that in the way freshness is remembered after a few months, mainly cleanness and taste (menthol-ness) are important. Apparently, people tend to value (temporary) sensory input during the actual freshness experience, but tend to remember the freshness result in the longer run.

Influence of hazelnut paste on the sensory properties and shelf-life of dark chocolate

Abstract: The addition of hazelnut paste to dark chocolate formulations altered the sensory profile. The flavors chocolate, burnt, rancid, hazelnut, green and metallic, and the texture attributes hardness, graininess, consistency of melt, viscosity and onset of melt determined by descriptive analysis were significantly (P < 0.05) influenced by the addition of up to 10% hazelnut paste. The shelf-life of dark chocolates containing hazelnut exceeded 10 months. The textural attributes of hardness, consistency of melt and onset of melt were highly correlated to instrumental measurements.

Evaluation of olfactory intensity: Comparative study of two methods

Abstract: Two experimental procedures recommended for the evaluation of the psychophysical characteristics of odorous compounds, olfactory matching with the 1-butanol scale and cross-modality matching with the finger span are compared. The intensity of ethyl butyrate and guaiacol solutions presented at four different concentration levels was evaluated by a panel of sixteen subjects over five repetitions using the two methods. Each stimulus was delivered to the subject from a Teflon bag through a nose-shaped glass sniffing port. The discrimination ability, repeatability, panel homogeneity and within-subject variability of the methods were assessed. Results indicate that with both methods, subjects were able to highly discriminate the presented concentration levels of the odorants. There were no great difference in repeatability and the same individual variability was observed between both methods. However, the smaller within-subject variability highlighted for the 1-butanol scale method suggested that this method is potentially more powerful than finger-span method.

Optimization of a chocolate peanut spread using response surface methodology (rsm)

Abstract: Response surface methodology was used to optimize formulations of chocolate peanut spread. Thirty-six formulations with varying levels of peanut (25-90%), chocolate (5-70%) and sugar (5-55%) were processed using a three-component constrained simplex lattice design. The processing variable, roast (light, medium, dark) was also included in the design. Response variables, measured with consumers (n = 60) participating in the test, were spreadability, overall acceptability, appearance, color, flavor, sweetness and texture/mouthfeel, using a 9-point hedonic scale. Regression analysis was performed and models were built for each significant (p < 0.01) response variable. Contour plots for each attribute, at each level of roast, were generated and superimposed to determine areas of overlap. Optimum formulations (consumer acceptance rating of ≥ 6.0 for all attributes) for chocolate peanut spread were all combinations of 29-65% peanut, 9-41% chocolate, and 17-36% sugar, adding up to 100%, at a medium roast. Verification of two formulations indicated no difference between predicted and observed values.

Induction of scaling errors

Abstract: Judges were required to rate the total intensity of NaCl solutions using a variety of unstructured category and line scales under a ‘rank-rating’ protocol and a traditional protocol that did not allow retasting or the reviewing of scores. The various scales and protocols induced two types of scaling errors. The first type was named a different-stimulus error. This involved a judge rating a stronger stimulus as equal to or less than a weaker stimulus. The second type was named a same-stimulus error. This involved a judge giving different ratings to two stimuli of equal concentration. For all scales, judges made a higher proportion of same-stimulus errors than different-stimulus errors. ‘Rank-rating’ only reduced the proportion of different-stimulus errors. It was hypothesized that a category scale with fewer categories would induce a higher level of different-stimulus errors but lower level of same-stimulus errors. These trends were noted but not always significantly. For line scales, the equivalent hypotheses regarding line length were either weak or not supported. It would appear that increasing the length of a line scale is not always equivalent to increasing the number of categories in a category scale.

Descriptive profiles of roasted peanuts stored at varying temperatures and humidity conditions

Abstract: Roasted peanuts were stored at 20 treatment combinations of water activities (0.33, 0.44, 0.54, 0.67, 0.75) and temperatures (23, 30, 35, 40C), and evaluated after storing for 0, 20, 40, 60, 80, 100, and 110% of estimated shelf life, ranging from 0 to 91 days. Regression models indicated that increasing storage time and storage water activity resulted in decreasing crispness, crunchiness, hardness, roasted peanutty, sweet aromatic, salty, bitter and sweet attributes and increasing fracturability, chewiness, tooth packing and cardboard flavor. Storage temperature did not contribute to regression models of textural properties of roasted peanuts. Increasing storage temperature resulted in a faster rate of decrease for roasted peanutty and faster rate of increase of cardboard flavor. Roasted peanuts stored between 0.33 and 0.41 a w at 23C are predicted to have the least change in sensory properties after 68 and 91 days respectively.

Comparison of the statistical analysis of hedonic data using analysis of variance and multiple comparisons versus an r‐index analysis of the ranked data

Abstract: Consumers rated a set of toothbrushes and a set of potato chips on 9-point and 21-point hedonic scales under two experimental protocols: a traditional approach and rank-rating. The hedonic data were analyzed in the usual way by using anova and multiple comparisons and also by ranking the data and using an R-index analysis. The hypothesis that the latter analysis would elicit fewer significant differences was not confirmed.

Use of confidence ellipses in a pca applied to sensory analysis application to the comparison of monovarietal ciders

Abstract: In a descriptive sensory analysis, a principal component analysis (PCA) is usually applied to analyze products with attributes. To visualize the variability of a mean point (i.e., the center of gravity of the product), we introduced confidence ellipses. In this particular application, resampling methods are performed. Twenty products composed of five varieties of cider were studied. We would like to know if these five varieties are different. Confidence ellipses reveal differences between varieties foreshadowed in PCA.

Panel performance and number of evaluations in a descriptive sensory study

Abstract: The assessor performance is a key point in a sensory evaluation. In particular, at the end of a session, a decrease of the performance can be feared. We propose to analyze this performance with various criteria: usual ones as the main product effect or the error variance; a new one measuring the perceived products variability. The performance can then be studied all along the session from two points of view: in taking into account the only products tested at a given instant (named instantaneous); in taking into account all the products tested up to a given instant (named cumulative). In the presented example, in spite of the large number of products successively tested by each assessor, the instantaneous performance of the panel shows no significant deterioration. Furthermore, when the number of products tested by each assessor increases, more significant product effects can be obtained thanks to the accumulation of the amount of data. This shows that the number of products that can be reasonably studied by one assessor during one session is generally underestimated.

Study on sensory and composition changes in italian amarone valpolicella red wine during aging

Abstract: Amarone is a red wine produced with a technique already known to the ancient Romans, based on withered grapes and a slow fermentation. Amarone is now considered to be one of the great Italian wines and it is exported all over the world. Sensory and compositional analyses were carried out to describe the profile of the Amarone over four vintages (1998–2001) at different stages of aging. All wines were analyzed for titratable and volatile acidity, pH, alcohol content, residual sugars, t-resveratrol, antioxidant power, color, tonality, total polyphenols and anthocyans. Twelve trained people evaluated aroma and flavor attributes of all the wines in triplicate in a sensory session. Principal component analysis (PCA) of chemical, physical and sensory data for Amarone wine allowed us to highlight the differences between the wines. In general, the 1998 and 1999 vintages had higher aroma and flavor of Wood and Alcohol than the 2000 vintage, which, on the other hand, had higher aroma and flavor of Liquor and Cherry in alcohol. In contrast, the younger wine (2001 vintage) was the more Astringent and had many polyphenols and anthocyans, distinctive features for a red wine that has been in the cask for a short time.

Segmentation approaches that differentiate consumption frequency from sensory preference

Abstract: People can eat a food without having a strong preference for it, and people can prefer a food without eating it. Given this seeming disconnect between attitude and behavior, which type of measure or segment can best be used to profile or identify loyal consumer segments of a food, such as soy? This research compares a usage-based method (heavy-light-nonusers) with a new attitude-based method (seeker-neutral-avoider), and finds that the attitude-based method differentiates purchase-related intentions better than the usage-based method. Implications for profiling consumer taste patterns and consumer segments are provided.

What features drive rated burger craveability at the concept level

Abstract: This paper deals with the analysis of drivers for self-defined craveability assessed in an Internet-based, conjoint analysis task. The stimuli comprised 36 descriptions of restaurant hamburgers, including product features, benefits, restaurant names, and emotional reactions that might ensue after eating the hamburger. Elements were combined into concepts by experimental design, and the resulting concepts evaluated by 145 respondents, on the attribute of craveability. Models relating the presence/absence of concept elements to ratings revealed that statements about the hamburger itself were the most powerful, but that no single element was highest across all the respondents. Segmentation of the 145 individuals by the pattern of their individual utilities revealed four key segments. These are Elaborates who may be sensory-oriented and respond strongly to product descriptions; Classics who like the notion of a grilled hamburger; Imaginers who respond to restaurant name and advertising copy; and Emotionals who respond to statements about food to descriptions how the eater feels after consumption.

Motivations for product consumption: Application of a probabilistic model to adolescent smoking

Abstract: This paper describes a method that can be used to investigate consumers' reported reasons for using a particular product. This method is applied to ratings of degree of agreement with statements about reasons for product use. The method is illustrated using data on self-reported reasons for smoking among adolescents. The approach used is based on a probabilistic model of similarity (Ennis et al. 1988) and provides a display of the density of respondents' individual motivations concurrent with their perceptions of the statements. Factor analysis and its derived factor scores provide complementary information which is used to understand the interdependence of smoking motivations with the age of respondents and their degree of smoking. The probabilistic similarity model has many applications in studying consumer motivations such as those involved in the consumption of particular food and personal care products.

Hispanic and non‐hispanic responses to concepts for four foods

Abstract: Hispanics and non-Hispanics Americans participated in four sets of studies dealing with health-oriented foods, with the goal to identify how they respond to food categories relevant in any cuisine. Each study comprised a conjoint analysis using 36 elements followed by a self-profiling questionnaire to learn more about Hispanic and non-Hispanic food responses to concepts for four different product categories (morning bread, bottled water, healthful salad dressing and popcorn as a snack). The study identified patterns of preference of marketing statements in the areas of health information, sensory characteristics, emotional benefits and endorsements. Conjoint utility values generated by both Hispanics and non-Hispanic respondents correlated highly, suggesting that their food attitudes are quite similar for “non-signature” products despite the differences in their original cuisines.

Comparison of new and existing methods for the classification of individuals according to 6-n propylthiouracil (prop) taster status

Abstract: We developed an alternative method for the determination of 6-n propylthiouracil (PROP) taster status that is based on the comparison of intensity ratings of PROP solutions with intensity ratings of visual, tactile, and kinesthetic (physical) stimuli. We then compared the classification obtained with this method to those derived from traditional approaches. One hundred and forty-two subjects rated the perceived intensity of 0.000032, 0.00018, 0.00032, 0.0018, and 0.0032 M PROP, and 0.01, 0.032, 0.1, 0.32, and 1.0 M NaCl, as well as five levels each of perceived roughness of sandpaper, grayness of shades, and thickness of honey and water mixtures on the Labeled Magnitude Scale (LMS). Ratings for 0.00032 M PROP and 0.1 M NaCl were also compared in a one solution test. Subjects were classified as PROP nontasters, tasters or supertasters by all three procedures. Seventy-six percent of panelists were classified in a similar way by the physical stimuli and NaCl procedures, while 70% percent of panelists were classified similarly by the physical stimuli procedure and the one solution test, as well as by the NaCl procedure and the one solution test. Only 65% of panelists were classified similarly by all three procedures. Further, in replicate ratings of PROP solutions, supertasters’ evaluations of PROP at all concentration levels decreased significantly (P < 0.01) from the first to the second rating. It is evident from these findings that the method used to determine PROP taster status can greatly influence the outcome of any investigation of PROP taster status on other phenotypes.

Relationship between oral and nonoral evaluation of texture in acid milk gels

Abstract: The objectives of this study were to compare oral and nonoral sensory evaluation for discrimination of texture of acid skim milk gels and to establish whether nonoral attributes could be correlated to the oral perception of texture. Trained panelists (n = 13) identified 11 nonoral (visual and in-hand) and 4 oral attributes during a preliminary profiling session that could be used to discriminate textures (P 87.5%).

Effects of sampling conditions on temporal perception of bitterness in yerba mate (ilex paraguariensis) infusions

Abstract: Time-intensity (TI) methodology and a trained panel were used to characterize the perceived bitterness of Yerba mate (YM) Ilex paraguariensis infusions. Two sampling procedures (sip and spit; sip and swallow) and two conditions for residence time in mouth (free or fixed duration of 5 s until spit or swallow) were evaluated. At a fixed duration the maximum bitterness as well as the time to reach it showed a significant YM concentration dependence. No change on bitterness was observed by swallowing or spitting YM infusions except a larger rate of decay of the response (vr) at spit condition. Dynamic bitterness at free sampling time showed that the decision period to spit or swallow the YM infusion approximately duplicated the fixed one of 5 s.

Release of artificial cherry flavor from ice creams varying in fat and fat replacers

Abstract: The effect of fat and fat replacers (FR) on the flavor release from cherry ice cream was investigated. Protein based FR, Simplesse (“S”) and carbohydrate based FR, Litesse (“L”) either partially or completely substituted milk fat in ice cream. Overall and temporal flavor profiles of ice cream during eating were obtained using chemical and sensory analyses. The performance of FR depended on the level of fat it was substituting and the amount of fat present in the ice cream. In the reduced fat ice cream group, both FRs failed to mimic the characteristics of 6% fat ice cream, mainly because of the low retention of cherry flavor. In the full fat ice cream group, the sensory properties of ice cream containing “L” were closer to the full-fat (12%) ice cream than those with “S”. The critical flavor volatile compounds that strongly impact the sensory flavor attributes were identified.