CONSUMER PREFERENCE OF DULCE DE LECHE AMONG STUDENTS IN THE UNITED KINGDOM

Dulce de Leche is a dairy-based confectionary product virtually unknown outside Latin America. A 2⁴ factorial design was implemented to study the influence of sugar composition, type of neutralizer, cooking time and presence of vanilla essence on the preference of Dulce de Leche by UK university students. A fractional factorial pattern was used in sen'ing samples to assessors. Analysis of variance showed that the preferred levels were: 40% replacement of sucrose by glucose syrup, 100% sodium bicarbonate as neutralizer, and no vanilla essence. Cooking time did not significantly affect preference. Partial least squares regression was used to relate preference to sensory profile scores. The correlation was good for appearance and texture, not so for flavor and aftertaste. A mapping technique showed consumers to be uniformly grouped for appearance and texture, not so for flavor. Results from preference and general acceptability were encouraging in promoting this new dairy product in Great Britain.     

PREFERENCE MAPPING OF TEXTURE OF DULCE DE LECHE

The texture of 12 commercial samples of dulce de leche was characterized by means of texture profile analysis. Two sensory manual texture attributes (hardness and ropiness) were evaluated by a panel of 11 trained assessors. A panel of 50 consumers evaluated the texture acceptability of the samples using a 9‐point structured scale. Consumers showed highly significant different degrees of liking for the texture of the evaluated samples of dulce de leche. Clusters identified with Pearson's correlation coefficient showed opposite preference patterns and provided more useful information regarding market segmentation than clusters identified with Euclidean distances. External preference mapping and partial least squares regression showed that hardness was a driver of liking for one segment of consumers, whereas for the other one it was a driver of disliking. When all the consumers were considered, external preference mapping indicated that the ideal texture of dulce de leche would be intermediate, showing the importance of identifying preference patterns and suggesting that data averaging in consumer preferences might affect information recovery, and may lead to wrong conclusions. Different preference mapping techniques were compared; it was found out that when the relationship between acceptability and texture attributes was not linear, external preference mapping showed the best results.     

CONSUMER PERCEPTION OF WHEY AND SOY PROTEIN IN MEAL REPLACEMENT PRODUCTS

ABSTRACT

Meal replacement products including protein bars, shakes and powdered drinks have increased in demand and sales. The objective of this study was to assess the consumer perception of protein content and type and product claims for meal replacement beverages and bars. The impact of exercise frequency on product perception was also investigated. Focus groups were conducted with exercisers and nonexercisers. An adaptive conjoint analysis survey was subsequently developed and conducted (n = 138 consumers, ages 18–35 years). Relative importance of product attributes was determined through a realistic trade‐off scenario. Utility scores were extracted and rescaled by the zero‐centered differences method, and two‐way analysis of variance was conducted to identify the differences between exercise frequency and product attributes. Both groups preferred bars to beverages, and no clear preferences were observed for protein type, which was consistent with focus group results of low knowledge/understanding of specific proteins. All respondents valued the products with low‐fat/fat‐free, calcium, all‐natural, protein, vitamin/mineral, heart health and muscle‐building claims. Exercisers viewed muscle‐building claims as more important than nonexercisers. Nonexercisers viewed heart health, calcium and vitamin/mineral claims as more important than exercisers. Three distinct consumer clusters were identified, and both exercise groups were found in all three clusters, although exercise frequency influenced membership in two of the three clusters (P < 0.05). These findings can be used to develop and market meal replacement products to specific consumer groups while leveraging their specific and unique needs.

PRACTICAL APPLICATIONS

Conjoint analysis provides a useful model of how consumers think during the purchase process and an understanding of the motivation for purchase through the testing of possible claims or product attributes. By applying this method to the purchase process of meal replacement bars and beverages, those in the field of development of these products can benefit from this information by being able to understand the motivation for purchase by the targeted consumer.     

EFFECTIVENESS OF CATEGORY AND LINE SCALES TO CHARACTERIZE CONSUMER PERCEPTION OF FRUITY FERMENTED FLAVOR IN PEANUTS

Fruity fermented (FF) flavor is a common off‐flavor in peanuts resulting from high‐temperature curing. The 9‐point hedonic scale is the most widely used scale to determine consumer acceptance; however, research has indicated that line scales may provide equal reliability and greater sensitivity. The objectives of this study were to characterize consumer perception of FF flavor in peanuts and to compare the effectiveness of the two scale types. Consumers (n = 208) evaluated control (no FF), low‐intensity (1.0) FF and high‐intensity (3.0) FF peanut pastes for the strength/intensity of roasted peanut flavor (RPF), sweet taste (ST), fresh peanut flavor (FPF) and overall liking (OV) using randomly assigned ballots. Sensitivity in defining consumer perception of off‐flavor in peanuts was greater with use of line scales than with the hedonic scale. The line scale indicated that FF flavor in peanuts, even at low intensity, negatively impacted OV and further identified significantly lower RPF and FPF perception by consumers. The hedonic scale identified only a difference in FPF and was not sensitive enough to show a difference in OV.     

SENSORY PROPERTIES AND CONSUMER PERCEPTION OF 'HOME-MADE'AND COMMERCIAL DAIRY ICE CREAM

Sensory properties and consumer perception of 2 'home-made'and 4 commercial dairy ice creams were examined. Conventional profiling by a trained panel found that most samples differed significantly in all attributes, but distinction of 'home-made'from commercial products was limited to few attributes. Principal component analysis separated the 'home-made'products from the commercial ones mainly on the basis of differences in appearance, aroma, creamy flavors and textural attributes. A consumer group (n=105) recorded preconception of 'home-made'ice cream acceptance, then received the product samples, in unlabeled condition, for assessment of degree of liking (DOL) and for identification as 'home-made'or commercial. Internal preference mapping of the DOL ratings showed that consumers were more closely grouped around samples which had higher intensities of certain attributes. Higher 'denseness', 'vanilla'aroma and 'buttery'flavor, were associated with more liking for commercial products. The 'home-made'high fat sample, although liked, tended to be grouped with commercial products. More marked textural attributes of 'ice crystals'and 'breakage'aided identification of the low-fat 'home-made'formulation, which was less liked overall. Overall, differences between the 'home-made'and commercial samples were small but consumer perception of the term 'home-made'was viewed favorably for dairy ice cream.     

SOME SOURCES OF BIAS IN CONSUMER TESTING

Data sets from three studies were examined to determine the effects of brand identification and package design on consumer responses during product evaluation. In these studies, consumers evaluated products with or without brand identification, compared products in standardized conditions, and compared products in different package designs with different or identical product contents. Measurement of consumer responses for all studies was based on 9-point hedonic scale. The results of the study showed that consumers were less critical in their evaluation when the samples being assessed were identified by brand names. Brand identification and package design, when not concealed in the comparison of product contents, resulted in consumer response bias. Also, the popularity of a brand influenced consumer's perception of products.     

TASTE PERCEPTION OF UMAMI-RICH DISHES IN ITALIAN CULINARY TRADITION

The aim of this research project was to investigate umami taste properties of recipes based on Italian culinary tradition and prepared with umami-rich ingredients, focusing on the impact of the preparation and ingredient combination. Gustative profiles were prepared for a traditional Italian dish, tender beef bouillon, usually consumed with pasta stuffed with beef. Four different samples were designed by changing the ingredients (with or without integrating Parmigiano cheese) and the preparation (cooking time) of the recipe. Panelists were rigorously trained for umami taste evaluation using monosodium L-glutamate (MSG) aqueous solutions and were then asked to evaluate umami sensation in tender beef bouillon with or without added Parmigiano Reggiano . A majority of the panelists were able to distinguish correctly umami sensations induced by MSG. The level of umami enhancement induced by Parmigiano Reggiano was clearly perceived by the panelists, and this enhancement positively affected also other basic tastes; whereas the cooking time had no clear effect on the gustative perception.

PRACTICAL APPLICATIONS

In western countries, people do not know much about umami. This taste is defined as the "savoriness" of the glutamate. Umami-taste substances are present in several foods, but whereas the taste of monosodium glutamate and 5' nucleotides can be without difficulty identified in water solutions, which are usually employed for panel training, the ability to identify this primary taste decreases enormously in more complex matrices like food. This study describes a procedure for screening and training sensory panels and could serve as a guide in teaching panelists to recognize and quantify the umami taste in a multistimuli matrix like a food recipe or product.
It also provides a practical application in a recipe in which the umami taste is modulated by the culinary preparation and ingredients.     

CONSUMER DRIVEN POLLEN LIMITATION OF SEED PRODUCTION IN MARSH GRASSES

While flower predators can limit the sexual expression and seed production of salt marsh grasses, the relationship between these two effects of consumers has not been explored. At our study site, predation on Spartina patens, Spartina alterniflora, and Distichlis spicata was twice as high in 1985 (~70% ovule destruction) as in 1986 (~35% ovule destruction). In both years consumers destroyed flowers before maturity, reducing sexual expression, and particularly suppressed male sexual expression. Sexual suppression of males was much more pronounced in 1985 when flower predation was severe and the seed production of undamaged ovules was dramatically reduced. A number of lines of evidence suggest that predator limitation of male sexual expression and pollen supply contributed to low seed output in 1985. 1) Undamaged ovules of all three grasses protected from consumers but exposed to ambient windbome pollen set many more seeds in 1986 than in 1985, suggesting that pollen was more abundant in 1986; 2) Artificial pollinations revealed that marsh grasses are generally pollen-limited and that pollen limitation at our study site was more severe in 1985 than 1986; and 3) Caging stands of marsh grasses generally led to less predator damage, increased male densities and seed sets similar to those for hand-pollinated flowers. Our results support the hypothesis that flower predators can indirectly limit seed production by decreasing pollen availability.     

PREDATOR PERCEPTION OF BATESIAN MIMICRY AND CONSPICUOUSNESS IN A SALAMANDER

In Batesian mimicry a palatable mimic deceives predators by resembling an unpalatable model. The evolution of Batesian mimicry relies on the visual capabilities of the potential predators, as prey detection provides the selective force driving evolutionary change. We compared the visual capabilities of several potential predators to test predictions stemming from the hypothesis of Batesian mimicry between two salamanders: the model species Notophthalmus viridescens, and polymorphic mimic, Plethodon cinereus. First, we found mimicry to be restricted to coloration, but not brightness. Second, only bird predators appeared able to discriminate between the colors of models and nonmimic P. cinereus. Third, estimates of salamander conspicuousness were background dependent, corresponding to predictions only for backgrounds against which salamanders are most active. These results support the hypothesis that birds influence the evolution of Batesian mimicry in P. cinereus, as they are the only group examined capable of differentiating N. viridescens and nonmimetic P. cinereus. Additionally, patterns of conspicuousness suggest that selection from predators may drive the evolution of conspicuousness in this system. This study confirms the expectation that the visual abilities of predators may influence the evolution of Batesian mimicry, but the role of conspicuousness may be more complex than previously thought.     

ESTIMATES OF CARRY-OVER EFFECTS IN TWO-PRODUCT HOME USAGE CONSUMER TESTS

In-house use consumer test data from four studies dealing with three pairs of household products and a pair of antiperspirant products were examined for significant carry-over (product usage order) effects, which would confound the analysis of treatment (product) effects. In each study, two products were compared using a two-period crossover design. One hundred twenty panelists participated in each study. A forced choice preference scale or a 9-point hedonic scale was used to obtain responses from various sensory attributes. In all studies, the estimates of carry-over effects were not significant at the 5% level. Transformation of hedonic scale data into preference dichotomy also gave estimates of carry-over effects which were not significant at the 5% level, but led to a loss of test sensitivity for detecting treatment differences. The authors recommend that all comparative crossover design studies in sensory evaluation be monitored for carry-over effects and that statistically determined sample size should be used to reduce the possibility of obtaining significant carry-over effects.     

USE OF TACTILE AND VISUAL CUES IN CONSUMER JUDGMENTS OF APPLE RIPENESS

The relative importance of visual and tactile cues in consumer assessments of'Royal Gala'apple ripeness were studied in relation to commercial maturity indices which included background color, blush, weight and skin greasiness. Apples were evaluated by consumers under 3 sensory conditions to isolate their use of visual and tactile cues. Individual fruit were harvested to provide apples which independently varied in background color, blush and weight. Visual cues of skin color were found to be greater drivers of perceived apple ripeness than tactile cues of skin greasiness and apple firmness. Amongst the visual cues tested, the hue of the background color had the greatest impact on consumer judgments of'Royal Gala'apple ripeness. Consumer's ideal'Royal Gala'apple ripeness was achieved with a background color between chip levels 5 and 8, blush coverage between 33-66% and weighing between 130-142 g.     

USE OF THE RECEIVER OPERATING CHARACTERISTIC IN THE STUDY OF TASTE PERCEPTION

Studies of the Receiver Operating Characteristic (ROC) for taste are reviewed and new data on its shape are presented. What evidence there is suggests that ROCs for taste conform to the normal-normal equal variance model of signal detection theory. Few ROCs for taste have been reported, probably because the large number of trials required by detection theory makes the task arduous for subjects in taste experiments. However, pooling ratings from several subjects and estimating the parameters of the pooled ROC by jackknife techniques circumvents that problem to some extent. Because experiments on taste are often based on a small number of trials, it is especially useful to determine the standard errors of ROC parameters. Methods for estimating these standard errors, including that of the area measure, p(A), are therefore presented.