The impact of PROP and thermal taster status on the emotional response to beer

Influence of taste sensitivity on preference and sensory perception of mezcal

The perception of orosensory stimuli, which includes flavor, can vary between individuals. These individual variations in oral sensations can be due to genetic factors and it would appear that they can predict food liking and consumption. The most studied source of variation is related to bitter taste perception associated with 6-n-propylthiouracil (PROP) responsiveness. In this context, humans can be classified as non-tasters (NT), medium tasters (MT) and supertasters (ST). Evidence suggests that genetic variation in bitter taste perception contributes to differences in the level of irritation caused by alcohol perception in solutions. The aim of this investigation was to study the bitter taste sensitivity among a group of mezcal consumers and its relationship with sensory perception and preference through PROP taster status. The tests were carried out in the state of Oaxaca in Mexico. A total of 83 mezcal consumers were classified by their PROP taster status and were asked to provide sensory descriptors for five mezcal samples and rate them according to the level of liking. The three-solution test was used to classify the subjects as NT, MT, and ST, while a Multiple Factor Analysis (MFA) was used to visualize the sensory descriptors provided by these three groups. The proportion of MT subjects was 16%, while the proportion of NT and ST was 34 and 51%, respectively. The MT provided higher liking ratings for at least three mezcal samples. According to MFA, the mezcal samples were organized in a similar configuration along the two dimensions. However, NT mentioned a limited number of simple terms (strong flavor, tasteless, burning in the mouth) to describe the samples, whereas ST used a more complex vocabulary (astringent, smoky, scratchy aftertaste). These data suggest that the preference for mezcal samples was similar for non-taster and supertasters, but there are indications that the sensory perception of mezcal differs between groups.

Consumer Studies: Beyond Acceptability—A Case Study with Beer

Beer is one of the most consumed alcoholic beverages in the world; its consumption and preference are evolving from traditional industrial beers of low complexity to novel craft beers with diverse flavour profiles. In such a competitive industry and considering the complexity of consumer behaviour, improvement and innovation become necessary. Consequently, consumer science, which is responsible for identifying the motivation behind customer preferences through their attitudes, perception and behaviour, has implemented strategies ranging from simple hedonic measurements to several innovative and emerging methodologies for a deeper understanding of the variables that affect the product experience: sensory, affective and cognitive. In this context, we offer a review inspired by previous research that explores some of the quantitative and qualitative methods used in consumer studies related to beer consumption, ranging from traditional approaches (acceptability, purchase intention, preference, etc.) to techniques that go beyond acceptability and allow a different understanding of aspects of consumer perception and behaviour (segmentation, expectations, emotions, representation, etc.). Also, innovative applications (contexts, immersive technologies and virtual reality, implicit measures, etc.) and current trends related to consumer science (Internet, social media, pairing, product experience, etc.) are addressed.

Emotional responses to taste and smell stimuli: Self-reports, physiological measures, and a potential role for individual and genetic factors

Taste and olfaction elicit conscious feelings by direct connection with the neural circuits of emotions that affects physiological responses in the body (e.g., heart rate and skin conductance). While sensory attributes are strong determinants of food liking, other factors such as emotional reactions to foods may be better predictors of consumer choices even for products that are equally-liked. Thus, important insights can be gained for understanding the full spectrum of emotional reactions to foods that inform the activities of product developers and marketers, eating psychologist and nutritionists, and policy makers. Today, self-reported questionnaires and physiological measures are the most common tools applied to study variations in emotional perception. The present review discusses these methodological approaches, underlining their different strengths and weaknesses. We also discuss a small, emerging literature suggesting that individual differences and genetic variations in taste and smell perception, like the genetic ability to perceive the bitter compound PROP, may also play a role in emotional reactions to aromas and foods.

Effect of Different Yeast Strains on Biogenic Amines, Volatile Compounds and Sensory Profile of Beer

Nowadays, there are many sorts of beer, however, some of them, despite the good sensory and other quality indicators, could contain high concentrations of undesirable compounds, such biogenic amines (BA). The yeast strain (YS), used for fermentation, can cause desirable as well as undesirable changes in beer. The aim of this study was to evaluate the contribution of different YS (A-Saccharomyces cerevisiae var. diastaticus, B-Saccharomyces cerevisiae var. bayanus, C-Brettanomyces claussenii) on the main quality parameters of beer. In addition, the BA concentration and the volatile compounds (VC, measured by gas chromatography–mass spectrometry) and their relation with beer overall acceptability (OA, evaluated by 20 trained judges) and emotions induced for consumers were analysed. The YS was a significant factor on alcohol formation in beer (p = 0.0001). The highest colour intensity was shown by C beer (10.2 EBC), and the latter beer showed the lowest OA. All of the beer samples induced the highest intensity of the emotion “neutral”, and the main VC of the beer were 3-methyl-1-butanol; L-α-terpineol; hexanoic acid 3-methylbutyl ester; and n-capric acid isobutyl ester. The highest total BAs content was found in beer fermented with C. Finally, all of the tested YS are suitable for beer production, however, taking into consideration the safety aspect of the beer, it should be mentioned that the highest concentration of BAs was found in beer fermented with C strain.

Comparing a new rapid combined method (RapCoTT) with traditional approaches for phenotyping thermal taste

Thermal taste is the phenomenon whereby taste is induced in some individuals through the application of a changing temperature stimulus to the tongue. Research into thermal taste is currently limited by inefficient phenotyping methods, which result in large numbers of unclassified individuals. This study evaluated the performance of a new, rapid combined phenotyping approach (RapCoTT) compared to two classification approaches using traditional phenotyping methods. RapCoTT was found to be more efficient at classifying participants, whilst showing consistency in classification with existing approaches. However, learning effects impacted the efficiency of all methods, which are a likely consequence of the unusual nature of thermal taste. It was concluded that three training steps be included for the phenotyping, namely taste exposure, TCATA training and a practice run. RapCoTT was found to evoke similar patterns of perceived tastes to other methods, with some exceptions. RapCoTT provides a more efficient tool for categorising participants for comparing sensory perception and food choice behaviours within the Thermal taste phenotype and provides a robust approach for future research into the phenomenon of thermal taste.

Self-Rated Aversion to Taste Qualities and the PROP Taster Phenotype Associate with Alcoholic Beverage Intake and Preference

Consumers often identify “taste” as an important factor when selecting alcoholic beverages. Although it is assumed that reduced alcohol consumption in PROP super-tasters is due to a greater dislike of the nominally aversive sensations that they experience more intensely (e.g., bitterness) when compared to PROP non-tasters, this question has not been specifically asked to them. Therefore, we examined consumers’ self-reported aversion towards specific sensory attributes (bitter, hot/burn, dry, sour, sweet, carbonation) for four alcoholic beverage types (white wine, red wine, beer, spirits) using a convenience sample of U.S. wine consumers (n = 925). Participants rated 18 statements describing different combinations of sensory attributes and alcoholic beverages on a 5-point Likert scale (e.g., Beer tastes too bitter for me). Individuals who tended to agree more strongly with the statements (i.e., they were more averse; p(F) < 0.05) tended to (i) consume less of all beverage types, (ii) consume a higher proportion of white wine (p(r) < 0.05), and (iii) were more likely to be female or PROP super-tasters. The results suggest that self-reported aversion to specific sensory attributes is associated with not only lower overall intake of alcoholic beverages, but also a shift in the relative proportions of beverage type consumed; a key finding for studies investigating how taste perception impacts alcohol consumption.

Perception of Aqueous Ethanol Binary Mixtures Containing Alcohol-Relevant Taste and Chemesthetic Stimuli

Ethanol is a complex stimulus that elicits multiple gustatory and chemesthetic sensations. Alcoholic beverages also contain other tastants that impact flavour. Here, we sought to characterize the binary interactions between ethanol and four stimuli representing the dominant orosensations elicited in alcoholic beverages: fructose (sweet), quinine (bitter), tartaric acid (sour) and aluminium sulphate (astringent). Female participants were screened for thermal taste status to determine whether the heightened orosensory responsiveness of thermal tasters (n = 21–22) compared to thermal non-tasters (n = 13–15) extends to these binary mixtures. Participants rated the intensity of five orosensations in binary solutions of ethanol (5%, 13%, 23%) and a tastant (low, medium, high). For each tastant, 3-way ANOVAs determined which factors impacted orosensory ratings. Burning/tingling increased as ethanol concentration increased in all four binary mixture types and was not impacted by the concentration of other stimuli. In contrast, bitterness increased with ethanol concentration, and decreased with increasing fructose concentration. Sourness tended to be reduced as ethanol concentration increased, although astringency intensity decreased with increasing concentration of fructose. Overall, thermal tasters tended to be more responsive than thermal non-tasters. These results provide insights into how the taste and chemesthetic profiles of alcoholic beverages across a wide range of ethanol concentrations can be manipulated by changing their composition.

Thermal taster status: Temperature modulation of cortical response to sweetness perception

Temperature is known to impact taste perception, but its reported effect on sweet taste perception in humans is inconsistent. Here, we assess whether thermal taste phenotype alters the temperature modulation of the brains' response to sweet samples and sweet taste perception. Participants (n = 24 balanced for thermal tasters (TT) and thermal non-tasters (TnT), 25 ± 7 years (mean ± SD), 10 males) underwent a thermal taste phenotyping session to study responses to cooling and warming of the tongue using a thermode. In a separate session, functional Magnetic Resonance Images (fMRI) were collected during sweet samples (87 mM sucrose) delivery at two temperatures ('cold' (5 ± 2 °C) and 'ambient' (20 ± 2 °C)) and the perceived sweetness intensity rated.In the phenotyping session, TTs had heightened perceptual temperature sensitivity to cooling and warming of the tongue using a thermode compared to TnTs. Although there was no significant effect during the fMRI session, the fMRI response to the 'cold sweet' sample across all participants was significantly increased in anterior insula/frontal operculum and mid-insula compared to the 'ambient sweet' sample, likely to reflect the perceptual difference to temperature rather than taste perception. TTs showed significantly increased fMRI activation patterns compared with TnTs and an interaction effect between thermal taster status and sample temperature, with TTs showing selectively greater cortical responses to 'cold sweet' samples compared to TnTs in somatosensory regions (SI and SII).The increase in cortical activation in somatosensory cortices to the 'cold sweet' stimulus correlated with perceptual ratings of temperature sensitivity to the thermode. The results highlight the importance of investigating the effects of thermal taster phenotype across a range of temperatures representing the reality of consumer consumption to beverages.

Thermal Taster Subgroups and Orosensory Responsiveness Dataset

Thermal taste is a phenomenon whereby some individuals, known as thermal tasters (TT) experience taste sensations when their tongue is warmed or cooled. It was first reported in 2000 by Cruz and Green [1] and since then, most research has focused on comparing TT to thermal non-tasters (TnT; individuals who do not experience thermally-elicited sensations). As TT rate the intensity of taste stimuli higher than TnT, understanding the nature of this difference may help inform how individual differences in taste perception impact consumer liking and consumption of food and beverages. However, as the mechanism(s) underlying thermal tasting are yet to be fully elucidated, it is unclear if TT should be considered a homogeneous group or if subgroups exist. We created a dataset to help determine if the orosensory advantage is universal across all TT, or if it is mainly attributable to one or more subgroups of TT. To this end, the thermal taste screening data of 297 TT from 12 previous recruitment drives (‘cohorts’) was combined. This created the largest dataset of TT reported to date in a single study, allowing for an in-depth analysis of the differences between TT. After training on appropriate scale use, participants were familiarized with common taste and chemesthetic stimuli (sweet, sour, salty, bitter, umami, astringent and metallic). Using a sip-and-spit protocol, participants rinsed with the stimuli and rated the maximum intensity each stimulus elicited on a generalized Visual Analogue Scale (gVAS) or a generalized Labeled Magnitude Scale (gLMS). To account for minor methodological differences between the cohorts, ratings from each cohort were first converted to z-scores before being combined into the overall dataset. Next, participants underwent a series of 12 trials that assessed response to a thermal elicitation device during which each combination of two temperature regimes (warming and cooling) and three lingual sites (tongue tip, 1 cm to left, 1 cm to the right) were examined in duplicate. Participants were asked to rate the maximum intensity of any sensations experienced during each trial. TT were classified into subgroups based on the type of thermally-elicited taste reported (typically sweet, sour, salty, bitter, metallic), the temperature regime during which the sensation was elicited (warming or cooling) and the location on the tongue tested at which the sensation was experienced. Figures are provided that show the mean intensity ratings of aqueous solutions of chemical stimuli and corresponding standard errors for each of the TT subgroups. In addition, the TT Subgroup Naming Conventions provided should allow for a consistent and clear use of terminology across future thermal taste research. Readers are referred to Homogeneity of thermal tasters and implications for mechanisms and classification[2] for a full discussion of how these findings inform our understanding of the mechanism(s) underlying thermal taste and the practical implications of methodological differences in determining thermal taste status.

Homogeneity of thermal tasters and implications for mechanisms and classification

Thermal tasting, an important type of individual variation in orosensation, is a phenomenon by which some individuals perceive thermally-induced taste sensations simply by having the tip of their tongue warmed or cooled. These individuals, known as thermal tasters, report a variety of thermally-elicited tastes (typically sweet, sour, salty, bitter, metallic) and the tastes reported can vary with the temperature regime used (warming or cooling) and location on the tongue tested. Importantly, when compared to thermal non-tasters, thermal tasters are more responsive to aqueous solutions of basic tastants and to beverages. The mechanism(s) underlying thermal tasting are not well understood and it is unknown if the increased orosensory responsiveness of thermal tasters is universal or if it is driven by a subgroup of thermal tasters. Thermal taste data from 12 previous studies was combined to obtain a large sample of thermal tasters (n = 254) who were divided into subgroups based on the type of thermally-elicited taste reported and the temperature regime/location at which it was experienced. Sweet thermal tasters (n = 77) were 9 times more likely than non-sweet thermal tasters (n = 177) to experience thermally-elicited sensations during lingual warming (p < 0.0001). Similarly, sour thermal tasters (n = 89) were 8 times more likely than non-sour thermal tasters (n = 165) to report thermally induced tastes during cooling (p<0.0001). However, no differences in orosensory responsiveness based on these or other subgroups were identified, suggesting that the heightened orosensory responsiveness of thermal tasters may be centrally-mediated. We discuss how these findings inform our understanding of the mechanism(s) underlying thermal taste and the identification of thermal taste subgroups, along with practical implications of methodological differences in determining thermal taste status.

Factors influencing the choice of beer: A review

Research on those variables that have been shown to influence the consumer's choice of beer is reviewed. The focus is on the choice of whether to drink beer as opposed to a beverage from another category, and to a greater extent, the choice between different types or styles of beer. Inspired by previous research on a diverse array of factors that have been shown to influence food and beverage choice, the review examines how beer choice is driven by consumer variables (covering biological, psychological, and socio-cultural factors), product-intrinsic attributes (the sensory aspects of the beer itself), product-extrinsic attributes (external sensory characteristics, such as packaging), and contextual and environmental influences. These situational factors refer to variables such as the location where choice/consumption takes place (i.e., on- versus off-trade), as well as the context, occasion, and reason for drinking. Current trends related to choice and consumption, such as the emerging interest in beer-food pairing, are also examined. The review groups these attributes which affect people's beer wanting, choice, and purchase in order to understand the beer consumer's choice process. Along with general conclusions, a number of key directions for future research are also presented, given that the relative contribution of each type of factor on consumer's choice behaviour is still unclear.

Measuring consumer emotional response and acceptance to sustainable food products

With current global challenges such as population growth, climate change and water scarcity, it is critical to develop sustainable strategies to achieve food security. One way to tackle this is by developing new products that use alternative and more sustainable ingredients. Bambara groundnut is a low-impact African legume as it can be grown on marginal soils and is resistant to high temperatures. The aim of this study was to investigate UK consumer acceptability and emotional response to snack products containing Bambara groundnut flour as an alternative sustainable ingredient. A key objective was to understand the contribution that measuring emotional response would reveal. Additionally the impact of extrinsic information on consumer acceptability and emotional response to snack products was investigated by sharing information concerning Bambara groundnut's sustainability and nutritional credentials. 100 UK participants were recruited to evaluate two biscotti and two cracker products. For each category a standard product made from standard ingredients sourced commercially, and one made replacing some of standard flour with Bambara flour were obtained. For each sample, participants were asked to rate their overall liking and emotional response based on sensory properties of the product (the blind condition). Participants were invited back for a second session, where they were informed about global resource challenges, and the sustainable features and nutritional value of Bambara, and which products contained this as an ingredient (informed condition). Under the blind condition, no significant differences in overall liking were observed between standard and Bambara products, indicating UK consumers accept the sensory properties of products that contain Bambara flour. Interestingly, the extrinsic information shifted consumer emotional response towards more positive emotions and less negative emotions when consuming products containing Bambara flour. It also made them felt less guilty when consuming the Bambara products, suggesting consumers engage with the idea of sustainable ingredients, and that this sustainable ingredient has potential for future new product development. It also highlighted the value of measuring emotional response for novel products to understand what may drive purchase behaviour when products are matched for liking. Food neophobia status did not impact product acceptability and emotional response between Bambara and standard products, however overall a lower emotional response was found for medium neophobic consumers in general who are more likely to evade novel products.

Exploring variability in detection thresholds of microparticles through participant characteristics

This study investigated how product familiarity and physiological characteristics of participants affect detectability of microparticles in viscous and semi-solid foods.