Article

Bitter taste markers explain variability in vegetable sweetness, bitterness, and intake

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Abstract

Intake of vegetables falls short of recommendations to lower risk of chronic diseases. Most research addresses bitterness as a sensory deterrent to consuming vegetables. We examined bitter and sweet sensations from vegetables as mediators of vegetable preference and intake as well as how these tastes vary with markers of genetic variation in taste (3.2 mM 6-n-propylthiouracil bitterness) and taste pathology (1.0 mM quinine bitterness, chorda tympani nerve relative to whole mouth). Seventy-one females and 39 males (18-60 years) reported prototypical tastes from and preference for Brussels sprouts, kale and asparagus as well as servings of vegetables consumed, excluding salad and potatoes. Intensity and hedonic ratings were made with the general Labeled Magnitude Scale. Data were analyzed with multiple linear regression and structural equation modeling. Vegetable sweetness and bitterness were independent predictors of more or less preference for sampled vegetables and vegetable intake, respectively. Those who taste PROP as most bitter also tasted the vegetables as most bitter and least sweet. The spatial pattern of quinine bitterness, suggestive of insult to chorda tympani taste fibers, was associated with less bitterness and sweetness from vegetables. Via structural equation modeling, PROP best explained variability in vegetable preference and intake via vegetable bitterness whereas the quinine marker explained variability in vegetable preference and intake via vegetable bitterness and sweetness. In summary, bitterness and sweetness of sampled vegetables varied by taste genetic and taste function markers, which explained differences in preference for vegetables tasted in the laboratory as well as overall vegetable intake outside the laboratory.

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... These current results agree with previous studies that showed that neophobic adolescents consumed fewer fruits and vegetables, mainly those with a bitter taste [2,15,17,24,26,[31][32][33][34][35], and that food neophobia was associated negatively with fruits, vegetables, and whole foods in children [22]. The current results are also consistent with previous data showing that the predilection for sweet and salty tastes was innate, while the aversion to bitter and sour tastes is a factor associated with food neophobia [3]. ...
... Within these factors, the taste characteristics of vegetables and consumption habits in the family environment play an important role in accepting or rejecting vegetables. Vegetables characterized by a bitter and astringent taste were less appreciated, while sweet and mild vegetables were more accepted [11,31,35,[44][45][46]. The adolescents described tomatoes, green beans, peas, potatoes, and zucchini as sweet and mild vegetables, and they accepted them. ...
... Age has a moderate influence on food neophobias in adolescents and can be corrected by means of educational programs. Food tastes have the highest effect on the appearance of food neophobia, mainly if a bitter taste is associated with these foods [2,8,9,12,15,17,24,26,[31][32][33][34][35][36]39,41]; however, other determinants, like familiarity with foods, place of residence, social setting, cultural influences, food context, and the availability of these foods [8,41,48], as well as parents' educational roles [41,42] are essential to avoid or to reduce food neophobias. ...
Article
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Food neophobia is a reaction of dislike or fear of food, which may be due to a wide variety of factors (taste, texture, exposure at an early age, genetics, or diversity in feeding practices and food consumption). The aim of this study was to assess the preferences for tastes and foods and food neophobias among Spanish adolescents and to compare the differences between boys and girls. This was a cross-sectional observational study on 11-18-year-old healthy adolescents (n = 600; 50% female) recruited in the Castilla-La Mancha region (central Spain). Information on taste preferences, food neophobias, anthropometric measurements, and sociodemographic data was recorded. The highest taste preference was found for sweet, salty, and umami. Most adolescents usually did not try new foods outside the home, nor did they like to try foods from other countries. More than half of them also acknowledged being selective eaters or were very particular about the foods they ate. There were no significant associations between taste preference and neophobias with obesity, waist-to-height ratio (WtHR), sleep, and smoking. Adolescents showed a high unwillingness to change food habits, and most of the food neophobias found in the current study were related to new, novel, or previously unknown foods. Spanish adolescents from central Spain (Castilla-La Mancha region) showed a preference for sweet, salty, and umami tastes of foods, as well as food neophobia towards foods that they do not regularly consume, mainly those with a bitter taste. Gender and body weight showed little influence, and age had a moderate influence on food neophobias. Familiarity with foods, as well as educational activities, are suggested as useful to decrease food neophobias among adolescents.
... For lager beer, variation in the endogenous sweetness and bitterness across individuals explains 27% of the variance in rated liking (Lanier et al., 2005). Likewise, similar effects are seen for kale and Brussels Sprouts (Dinehart et al., 2006). In contrast, the bitterness of coffee varies across individuals, but this does not predict liking Lanier et al., 2005). ...
... Understandably, most studies do not examine the multiple levels of data shown in Fig. 4.1 within a single group of individuals, focusing instead on narrower questions like the correlations between pairs of variables (e.g., Caporale et al., 2009;Lucas and Bellisle, 1987). Some of the studies that do look down the chain from sensation to intake within a cohort include (Hayes et al., 2010;Lanier et al., 2005;Lucas et al., 2011;Dinehart et al., 2006;Byrnes and Hayes, 2013). A study by Lucas and colleagues on hash browns (fried potatoes) illustrates the dif culties that can arise in this approach (Lucas et al., 2011). ...
... Studies on habitual intake of alcohol and vegetables have demonstrated relationships between sensation and intake that are mediated via liking (e.g., Lanier et al., 2005;Dinehart et al., 2006), which potentially explain studies that directly link taste gene variation to differential intake without measuring the intermediary variables Duffy et al., 2004;. Other studies nd relationships between food preferences and diet related health outcomes even in the absence of observed relationships with intake (Duffy et al., 2007;. ...
... Surprisingly, more South Non-Vegetarians answered "No" to consumption of non-meat alternatives, compared to Non-South Non-Vegetarians. The finding resembles previous studies on the high prevalence of bitter taster alleles of the gene TAS2R38 in the South population (homozygous PAV/ PAV and heterozygous PAV/AVI), which accounts for less likeliness of South Indians to prefer a non-meat based vegetable diet [63], [64], [65], [55] . Assessment of preferred Food Categories according to Taste supplements this finding. ...
... This heritability is seen a little more pronounced in Non-South than South, presumable as South Indians reportedly carry higher frequency of TAS2R38 bitter taste perception gene variant (homozygous dominant PAV/PAV or heterozygous dominant PAV/AVI) than Non-South, who carry more of homozygous non-taster (recessive AVI/AVI) allelic variant [55] . This is because people who perceive more bitterness report less liking of vegetables (PAV/PAV or AVI/AVI) and hence consume fewer vegetables [63], [65], [83] . ...
... For tea/coffee, mean scores were 6 in Non-South and 7.6 in the South population. Further, lower weekly frequency of tea/coffee in the present sample population [65] is confirmed by studies on polymorphic variants of bitter-taste gene TAS2R43 that influences coffee liking [85] , and PLCâ2 gene rare allelic variant rs2290550 reportedly linked to tea liking [65] . ...
Article
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This study determines the factors associated with food preference, in the South and Non-South Indian populations, comparing and contrasting their results. 100 Indian young adults between 17-30 years of age, participated in an online questionnaire, comprising Multiple Choice, Open-ended and short answer questions. Food Choice Questionnaire (FCQ), Food Choice Motivations (FCM), and Food Choice Frequency data were also included in the survey. Mean Food Item frequency scores were also determined. Descriptive Statistical Data analyses were used to extrapolate data and obtain results. Food Choice behavior against 4 parameters, namely “Taste/Sensory Appeal”, “Fussiness”, “Health Concern” and “Frequency of Intake” was observed separately for each group. The hereditary pattern of the parameters across 10 different food categories was also ascertained. Food Frequency data describing the ten most commonly consumed Food Items in both South and Non-South populations were obtained. These food preferences were correlated with previous studies relating to gene regulation of dietary preferences. “Food Quality” emerged as the most significant factor affecting food choice, with 58% of respondents scoring likeliness, followed by Taste/Sensory Appeal (57%) and Food Availability (43%). The least common factors were Peer Influence (6%), Vegetarianism/Self-Identity (10%), and Animal Welfare/ Ethics (10%). This is a first-of-its-kind study on the integrated effects of various factors and motivations behind Food Choices, in an Indian setting. It carries a multidimensional approach to determining the eating behavior of the Indian youth population, taking the genetic make-up of the individual into account while analyzing choice decisions.
... The interactions between sensory active compounds (glucosinolate, isothiocyanates, phenolics and polysaccharides) in vegetables (3 cultivars of broccoli, 5 of Brussels sprout, 3 of cauliflower, and 4 of kohlrabi, both raw and cooked) and sensory characteristics were analyzed by Wieczorek. 33 Results of PCA showed 34 To compared with previously published report, 35 the levels of bitterness compounds in vegetables (Brussels sprouts, kale and asparagus) positively correlated to hedonic scales (r= 0.45) but negatively correlated to acceptance (r= -0.28).Besides, perception intensity of bitterness and acceptance were significantly negative correlated (r= -0.22, p < 0.01); while perception intensity of sweetness and acceptance were significantly correlated (r= 0.34,p < 0.01). Unpleasant tastes including bitterness, astringent and grassy flavor deterred vegetable consumption. ...
... Unpleasant tastes including bitterness, astringent and grassy flavor deterred vegetable consumption. 35 Incorporation of vegetable puree into desserts and salty dishes was suggested to increase vegetable intakes. 36 In this study, palatability improved by blanching and seasoning addition might provide an alternative approach to promote vegetable consumption. ...
Article
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Broccoli provides a good source of many nutrients and bioactive compounds. However, bitterness of broccoli deterred sensory desirability and furthermore impacted its consumption. Cooking and seasoning addition can be used to reduce the bitterness and to increase the preference of vegetables. The objective of this study aims to investigate the effect of blanching and flavor enhancement with various sauces on the bioactive and organoleptic properties. Broccoli was prepared: raw (C), blanched (B), blanched and flavored with Japanese style sauce (F1), with cheese (F2), and with Chinese style sauce (F3). The bioactive compounds (polysaccharide and phenolic compounds), antioxidant properties (DPPH and ABTS scavenging activities), and sensory preference characteristic were evaluated. The results showed blanching and combined with seasonings significantly altered the color parameters (a*, C* and ho) of broccoli. While blanching and sauces additions improved antioxidant contents and capacity as well as all sensory acceptances tested. Compared to the control, blanching and sauces additions increased the contents of phenolic compounds and polysaccharides from 8.3 to 8.4-10.0 and from 78 to 93-106 mg/g dw, respectively. While blanching and sauces increased the scavenging capacity of DPPH and ABTS from 1.29 to 1.43-1.83 and from 3.28 to 4.52-5.27mg Trolox/100g, respectively. Principal component analysis (PCA) analysis further showed blanching and sauces additions were positively correlated with the acceptance of flavor, taste and overall but negatively correlated to color acceptance. In conclusion, blanching or flavorings retained color acceptance (sensory score >5) and enhanced antioxidant capacity and sensory preference.
... Kale in both environments was separated from all other samples and mainly related to emotions such as , , and and negatively related to all positive emotions. This may be due to the bitter taste characteristic of kale, which tends to be rejected by consumers as a genetic and neurological response from a human evolutionary trait related to its association with poison avoidance [29][30][31] . Figure 2C shows farther. ...
... While kale in both environments and Thai basil in neutral environment were related to HR, systolic and diastolic pressure, and sadness. This may be due to the higher bitterness in these samples that elicit an alertness state in the brain and physiological responses due to the association with poisonous substances [29][30][31] . On the other hand, Thai basil and coriander in the space environment were associated with engagement, disgust, surprise, and fear, while beetroot , sweet basil and lettuce in the space environment were mainly related to the aroma, pitch , texture, and overall liking. ...
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Novel research related to food perception is required for long-term space exploration planned in the next 20 years. Limited research has been done on sensory analysis of food and beverages in space and space-simulated conditions, with many studies presenting biases from the perspective of sensory analysis and statistical methods. This study used conventional, biometrics, and multivariate data analysis on data obtained from pick-and-eat leafy greens as a model to assess self-reported consumer sensory analysis on microgravity simulated conditions through reclining chairs and space-immersive environments. Results from the multivariate analysis showed effects on the self-reported, physiological, and emotional perception of samples in space-related positions and environments related to changes in sensory perception. Objective digital information obtained through non-invasive biometrics could offer a powerful tool for developing artificial intelligence models and digital twins that can be used to assess genetically modified plants and plant-based food and beverage products for long-term space exploration.
... 17 The TAS2R38 gene encodes for bitter taste receptors that bind bitter compounds such as phenylthiocarbamide (PTC). Individuals can be classified as PAV/PAV homozygotes, AVI/PAV heterozygotes, or AVI/AVI non-tasters based on their sensitivity to PTC. 18 The distribution of these genotypes varies globally, with the non-taster genotype being most prevalent in Africa and the Middle East. 19 However, PTC taster status was inversely correlated with Rh-negative blood type. ...
... PTC paper testing is subject to user errors and cannot distinguish heterozygotes from homozygotes. 18 PCR-based genotyping should be employed to definitively assign genotypes. No specific variants reported conferring Rh-negative status, which could help explain the correlation with PTC taster status. ...
... 6-9 However, the literature is controversial, with some studies showing no association between body mass index and bitterness perception. 4, 10,11 On the other hand, supertasters are more likely to be selective in food choices because they are less inclined to consume certain bitter-tasting foods (eg, some fruits and vegetables), which are important source of phytonutrients. 10 Consequently, they may be at a greater risk of developing metabolic diseases. ...
... 4, 10,11 On the other hand, supertasters are more likely to be selective in food choices because they are less inclined to consume certain bitter-tasting foods (eg, some fruits and vegetables), which are important source of phytonutrients. 10 Consequently, they may be at a greater risk of developing metabolic diseases. 12 TAS2Rs are present not only in the mouth or throat but also in several other body tissues, such as the lower and upper respiratory tracts, brain, bladder, and the gastrointestinal tract (GIT). ...
Article
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Bitter taste is an aversive taste because it is unconsciously associated with toxic compounds. However, a considerable variability in bitter sensitivity exists in those who have the genetic polymorphism for bitter taste receptors (TAS2Rs). Besides the oral cavity, TAS2Rs are present in many body tissues, including the gastrointestinal tract; therefore, they are crucial players both in the gustatory/hedonic system and in the homeostatic system, triggering numerous biological responses, including adipogenesis, carcinogenesis, or immunity. Bitter-tasting compounds are widely distributed in plant and animal foods and belong to many chemical classes. In this study, the evidence was reviewed on bitter peptides, considering the food sources, their formation in food under different processing and storage conditions and in the gastrointestinal tract during digestion, as well as their biological activities. Bitterness associated with peptides is due to the presence of hydrophobic amino acids in the C-terminus. The current literature mainly explores the enzymes and hydrolysis conditions, with the aim of reducing the formation of bitter peptides in hydrolysate preparation or food. Few studies highlight the bioactivity (namely, antihypertensive, antidiabetic, antioxidant, or immunity boosting), besides the bitterness. However, encapsulation of bitter peptides has been tentatively used to develop antihypertensive and antidiabetic supplements. In the era of personalized nutrition and precision medicine, the evidence available suggests the opportunity to use bitter bioactive peptides as functional ingredients in food. Such types of food may modulate a plethora of physiological mechanisms by targeting TAS2Rs in the gastrointestinal tract, thus modulating appetite sensations or gastrointestinal motility and discomfort according to individual nutritional needs and goals. More studies are needed to optimize the technological strategies to target TAS2Rs by bitter bioactive peptides, improve their stability in food, and validate the biological efficacy through well-designed in vivo studies.
... Moreover, the Tas1R2 gene encodes a singlenucleotide polymorphism (SNP) that affects sweet perception and sugar intake in a BMIdependent manner (BMI above 25) [12], while polymorphisms of the bitter taste receptor T2R38 result in supertasters for bitterness. It could lead to the avoidance of some vegetables and fruits (e.g., Brassica ssp., spinach, bitter citrus, and green tea) and increased consumption of sweet and fatty food, thereby increasing the risk for chronic metabolic and inflammatory diseases [13]. The transient receptor potential cation channel subfamily M member 5 (TRPM5) is a voltage-sensitive, monovalent cation-selective channel. ...
... Table 1. Taste receptors and their ligands of enteroendocrine cells and changes incretin hormone secretion in IBD patients [9][10][11][12][13][14]. ...
Article
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The consumption of artificial and low-calorie sweeteners (ASs, LCSs) is an important component of the Western diet. ASs play a role in the pathogenesis of metabolic syndrome, dysbiosis, inflammatory bowel diseases (IBDs), and various inflammatory conditions. Intestinal nutrient-sensing receptors act as a crosstalk between dietary components, the gut microbiota, and the regulation of immune, endocrinological, and neurological responses. This narrative review aimed to summarize the possible effects of ASs and LCSs on intestinal nutrient-sensing receptors and their related functions. Based on the findings of various studies, long-term AS consumption has effects on the gut microbiota and intestinal nutrient-sensing receptors in modulating incretin hormones, antimicrobial peptides, and cytokine secretion. These effects contribute to the regulation of glucose metabolism, ion transport, gut permeability, and inflammation and modulate the gut–brain, and gut–kidney axes. Based on the conflicting findings of several in vitro, in vivo, and randomized and controlled studies, artificial sweeteners may have a role in the pathogenesis of IBDs, functional bowel diseases, metabolic syndrome, and cancers via the modulation of nutrient-sensing receptors. Further studies are needed to explore the exact mechanisms underlying their effects to decide the risk/benefit ratio of sugar intake reduction via AS and LCS consumption.
... Previous studies have demonstrated that the TAS2R28 genotype affects the perception of bitterness in Brassica vegetables [29][30][31]. In addition, studies have also reported that TAS2R38 can influence intake and/or liking of other vegetables (not just Brassica vegetables) [32][33][34][35][36]. ...
... The results also showed that both bitter and sweet perception were significant predictors for taste liking in turnip. Similar findings were reported in previous studies where consumers' preferences for vegetables were influenced by lower bitterness and higher sweetness [33,[39][40][41]. This pattern was particularly true for the consumers in cluster 3 (22.4% of the study population), who liked the roasted turnip significantly more than the boiled-and steamed-pureed turnips, and for whom the roasted turnip was positively associated with a sweet taste and negatively associated with a bitter taste. ...
Article
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Brassica vegetables are bitter, predominantly because they contain bitter-tasting glucosinolates. Individuals with high bitter taste sensitivity are reported to have lower consumption of bitter vegetables. Studies reported that cooking methods can alter the sensory characteristics of vegetables, increasing acceptability. This study investigated consumer liking of turnip cooked by four methods (boiled-pureed, roasted, steamed-pureed and stir-fried) and related this to sensory characteristics. Additionally, this study examined the effect of the bitter taste genotype on taste perception and liking of the cooked turnip samples. Participants (n = 74) were recruited and the TAS2R38 genotype was measured. Liking, consumption intent, perception of bitterness and sweetness of turnip were evaluated. A sensory profile of the cooked turnip variants was also determined by a trained sensory panel. There were significant differences in the overall (p = 0.001) and taste (p = 0.002) liking between cooking methods. Turnip liking was increased when preparation led to sweeter taste profiles. The TAS2R38 genotype had a significant effect on bitter perception (p = 0.02) but did not significantly affect taste liking. In conclusion, the cooking method affected turnip liking, and the bitter perception in turnip was influenced by the TAS2R38 genotype. However, taste sensitivity did not predict turnip liking in this UK adult cohort.
... The link between bitter taste sensitivity and food preferences was suggested in some studies, for example, by observing higher bitter taste sensitivity resulting in lower vegetable acceptance and intake during childhood and adolescence (Dinehart et al., 2006), or in the adult population (Sandell et al., 2014). Nevertheless, this is not consensual, and some authors failed to observe this relationship (De Toffoli et al., 2019;Mohd Nor et al., 2021;Yousaf & Tepper, 2022). ...
Chapter
Functional foods are industrially produced or natural foods that, when consistently included in a varied diet and taken in effective quantities, may offer health benefits. This chapter aims to discuss the determinants (drivers and barriers) documented in the existing literature that can influence consumer choice and strategies for educating consumers to empower them to make informed choices regarding functional foods. Pushing functional food success requires a deep understanding of key determinants that shape consumer acceptance, such as physiology and sensory perception; sociodemographic, lifestyle, and psychological; nutritional and health benefits; nutrition labeling, legislation, and regulations; sustainability and environmental impacts determinants. Educating consumers and enhancing their knowledge appear to be the most effective strategies to improve their decision-making process regarding functional food. Dissemination and perennialization of adequate knowledge and evidence-based communication among different stakeholders seem to be the most promising ways to increase consumers’ interest in functional foods. Achieving this objective requires the development of diverse programs at school levels, scientific seminars, and engagements with policymakers. Finally, extensive research is required to overcome the challenges involved in the adoption of the new technologies during the development of functional food.
... This preference for beers brewed with repelletized hop residues by the panelists is explained by a low preference for bitterness and hop flavor, and a significant preference (p < 0.05) for sweetness. Multiple studies have analyzed the relationship between bitterness perception, preference, and food consumption, finding that people with greater sensitivity to bitterness generally exhibit less liking for bitter products [47][48][49]. Furthermore, it has been observed that more adventurous tasters (judges) tend to rate bitter fruits and vegetables more favorably than less adventurous tasters (consumers), who typically assign lower ratings to these foods. ...
Article
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Hops are an important component of beer brewing, providing aromatic and bittering properties that are essential to consumer appeal. A significant amount of hop residue is generated in the dry-hop brewing process that cannot be reused due to bittering residues that disqualify them as animal feed or other products. The purpose of this research was to reuse four varieties of hop waste (Citra, Mosaic, Hallertau Blanc, and Mandarina Bavaria) through a repalletization process with the objective of integrating them into a new craft beer brewing process. Chemical properties such as the phenolic content, antioxidant capacity, and α- and β-acids were significantly reduced (p < 0.05) due to the reuse of the repelletized hops, leading to a decrease in the bitterness levels in all of the craft beers brewed with dry-hop residues. Finally, the sensory study conducted with non-habitual craft beer consumers revealed significant general acceptability for beers brewed with repelletized dry-hop residues (Mandarina Bavaria, Citra, and Mosaic). The reuse of hop residues for brewing presents a promising opportunity for further development in the food industry.
... It has been shown that PROP status and papillae number independently explained variability in consuming high-sodium foods by impacting salt sensation and/or liking (Hayes et al., 2010). Several studies have used actual food (Dinehart et al., 2006;Lanier et al., 2005) or model foods with varied concentrations of a tastant (Bolhuis, Costanzo, Newman, & Keast, 2016;Bolhuis, Lakemond, de Wijk, Luning, & de Graaf, 2012;Monteleone et al., 2017;Pagliarini et al., 2021; to evaluate taste responsiveness, indicating sensoryhedonic linkages (Endrizzi et al., 2022;Spinelli et al. 2021Spinelli et al. , 2024. ...
... Moreover, cooking makes food plants, particularly vegetables, palatable [29]. The bitter taste of some vegetables, identified as a significant obstacle to their consumption, can be minimized through certain cooking processes and the addition of spices [30][31][32]. According to Poelman et al. [33], enhancing the flavor of vegetables by cooking can increase their consumption, particularly among children. ...
Article
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Abstract The Sundanese people of West Java, Indonesia are well known for consuming raw plants as part of their food culture called lalapan. West Java consists of several traditional villages, one of them is Banceuy Traditional Village which is located in Subang Regency. Usually, discourse about food is inseparable from culture since every places has unique dishes and cultures. This study aimed to conduct quantitative analysis of the inventory of food plant data using quantitative ethnobotanical indices. Method of research used semi-structured interviews with 32 informants that consisted of 2 key informants and field-guided observation accompanied by one of the key informant around the village to identify and collect the food plant specimens. A quantitative data analysis was carried out using ethnobotany indices namely, Index of Cultural Significance (ICS), Use Values Index (UV), and Relative Frequency Citation (RFC). Banceuy indigenous people utilized 160 local food plant species belonging to 55 families. Fabaceae, Cucurbitaceae, Solanaceae, and Zingiberaceae were the dominant food plant families. These plant species were utilized as sources of carbohydrates, fruits, vegetables, spices, seeds, and beverages. The most applied food consumption manner by Banceuy indigenous people consisted of fresh consumed, sauté, and boiled . Arenga pinnata had the highest ICS value (116) due to its utilization as seasoning and involved in traditional ritual. Manihot esculenta and Carica papaya had the highest value in UV (1.81 & 1.69) and RFC (both 0.97) as they were used for daily consumption.
... Individual differences in PROP perception have frequently been correlated with the intensity of other oral stimuli. Several studies have demonstrated that responsiveness to PROP is positively associated with responsiveness to chemosensory stimulation in taste model solutions (Prescott et al. 2001;Hayes et al. 2008;Fischer et al. 2014;Webb et al. 2015) and real food (Dinehart et al. 2006;Zhao and Tepper 2007;Masi et al. 2015;Dinnella et al. 2018;Spinelli et al. 2018;Robino et al. 2022). The perception of PROP bitterness was found to be positively associated to the perception of tactile/texture-related sensations such as astringency (Pickering and Robert 2006;Melis et al. 2017), creaminess (Kirkmeyer and Tepper 2003), and roughness (Bakke and Vickers 2008). ...
... Individual differences in PROP perception have frequently been correlated with the intensity of other oral stimuli. Several studies have demonstrated that responsiveness to PROP is positively associated with responsiveness to chemosensory stimulation in taste model solutions (Prescott et al. 2001;Hayes et al. 2008;Fischer et al. 2014;Webb et al. 2015) and real food (Dinehart et al. 2006;Zhao and Tepper 2007;Masi et al. 2015;Dinnella et al. 2018;Spinelli et al. 2018;Robino et al. 2022). The perception of PROP bitterness was found to be positively associated to the perception of tactile/texture-related sensations such as astringency (Pickering and Robert 2006;Melis et al. 2017), creaminess (Kirkmeyer and Tepper 2003), and roughness (Bakke and Vickers 2008). ...
... 92 It is specifically the addition of the words 'of any kind' that is considered particularly important to help generalize the scale since they help to provide a wide frame of ref. 93. Other studies of taste differences have used external references to standardize the ratings, including sound, 94,95 light, 96 or the perception of weight, from a variety of sand-filled jars. 97,98 While these careful methods provide a clear cross-modal reference for the validation of responses, they are resource intensive for larger studies, which may instead use remembered sensations (e.g., 'brightness of a well lit room'). ...
Chapter
Large amounts of money, time and effort are devoted to sensory and consumer research in food and beverage companies in an attempt to maximize the chances of new products succeeding in the marketplace. Many new products fail due to lack of consumer interest. Answers to what causes this and what can be done about it are complex and remain unclear. This wide-ranging reference collates important information about all aspects of this in one volume for the first time. It provides comprehensive, state-of-art coverage of essential concepts, methods and applications related to the study of consumer evaluation, acceptance and adoption of new foods and beverages. Combining knowledge and expertise from multiple disciplines that study food sensory evaluation and consumer behaviour, it covers advanced methods including analytical, instrumental and human characterization of flavour, aspects of food processing and special research applications of knowledge and methods related to consumers’ evaluation of new food products. Researchers and professionals working in food science and chemistry are sure to find this an interesting read.
... Vegetables contain various phytochemicals that provide health benefits but also impart a bitter taste [61], which has long been considered a deterrent for vegetable consumption [62,63]. Previous studies have suggested that individuals who are less sensitive to bitter taste tend to have a greater liking and familiarity with vegetables [64], which in turn facilitate adherence to a plant-rich diet [65]. However, this is not consistent with our findings of increased sensitivity or intensity perception of bitterness amongst those classified as plant-based dieters, although our meta-analysis failed to find any notable difference in bitter thresholds between these two dietary groups. ...
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Driven by heightened awareness of environmental sustainability, personal health, and animal welfare, there has been a rapid surge in adoption of plant-based diets (PBDs) by global consumers. Despite the important implications of potential links between PBDs and chemosensory (e.g., olfactory and gustatory) perception, the empirical evidence has yet to be comprehensively reviewed. This systematic review aims to synthesise existing data comparing olfactory and gustatory perceptions among individuals following plant-based (including vegan, vegetarian, and flexitarian) and omnivorous diets. Seven databases produced 1038 publications for screening against the pre-registered criteria. Eleven studies were included in this review, with three focusing on olfaction and eight on gustation. Of these, three gustatory studies provided sufficient data for meta-analysis, revealing little difference between plant-based and omnivore dieters on an overall level. The PBD group exhibited a significantly lower threshold (i.e., higher sensitivity) to sweetness compared to the omnivore group (ES = −0.336, 95% CI between −0.630 and −0.042, p < 0.05). Additionally, olfactory studies indicated that PBD followers perceived meat-related odours to be less pleasant compared to omnivores. Overall, this review points to a sensory–diet relationship, highlighting the potential role of sensory perception in sustainable plant-based dietary behaviours. The findings also encourage food manufacturers to consider potential chemosensory alterations among plant-based consumers.
... Vegetables-dark-green vegetables specifically-are promising targets for this focus. Dark-green vegetables such as those in the Brassica family (e.g., broccoli, kale, and cabbage) and other leafy greens contain high concentrations of health-promoting phytochemicals, fiber, and micronutrients, and yet also are often less liked due to aversive sensory properties including bitterness, astringency, and sulphureous smells (Dinehart et al., 2006;Wieczorek et al., 2018). ...
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Unpleasant flavor is a commonly stated reason for avoiding vegetables. However, repeated exposure to flavors, even unpleasant vegetable flavors, improves acceptability. Yet, increasing exposure to vegetables is difficult, as vegetables can be less convenient, available, and affordable than other foods. This study describes a method to circumvent these barriers to repeated flavor exposure. We designed a game with vegetable‐ or control‐flavored gummies, where players (N = 34) were challenged to identify the flavors over 2 weeks. One round was played per day, and the questions and gummies were designed to make it harder to identify the flavors as the game progressed. At screening, qualified subjects needed to consume <2.5 servings of nonstarchy vegetables per day as well as dislike at least one “target” and one “non‐target” vegetable. The “target” vegetables (kale and broccoli) were included in the game and the “non‐target” vegetables (asparagus and spinach) were included in sensory tests but not the game. Vegetable liking ratings were measured at baseline (before gameplay), after 1 week of gameplay, and after 2 weeks of gameplay. Pilot data indicate one target vegetable (kale) increased in liking after 1 and 2 weeks of gameplay among the vegetable group, but not the control group. Liking for broccoli (other target vegetable), as well as asparagus and spinach (nontarget vegetables), did not significantly change for either group. Thus, our “gamified” approach to vegetable flavor exposure may be useful in increasing acceptance of some vegetables, but additional work to identify why the game improved liking for kale but not broccoli is needed.
... Personality traits, such as food neophobia and sensitivity to disgust, have also been found to affect both sensory responses and liking of pungent and bitter foods Spinelli et al., 2018). Further, differences in the perceived intensity of bitter compounds such as 6-n-propylthiouracil have been found to be associated with hedonic responses to foods, although some results conflict (Dinehart et al., 2006;Duffy et al., 2003Duffy et al., , 2010Duffy et al., , 2016Masi et al., 2015;Prescott et al., 2004). Other indices of oral responsiveness independent from PROP have been proposed to further explore this link between taste responsiveness and hedonics (Hayes & Keast, 2011). ...
Article
Over the last half-century, variable responses to sweetness have repeatedly been shown to fall into a small number of hedonic responses, implying that looking only at group means may can obfuscate meaningfully different response patterns. Comparative data for sourness is quite sparse, especially in adults. While increased liking with higher acid concentration has been reported for some children, in adults, sourness is classically assumed to be aversive, with a monotonic drop in liking with increasing sourness. Here, we test this assumption using a simple model system or an experimental beverage in convenience samples of adults from the United States (increasing citric acid in water) and Italy (increasing citric acid in pear juice). Participants rated intensity and liking of sampled stimuli. For both cohorts, we find clear evidence of three distinct patterns of responses: a strong negative group where liking dropped with increased sourness, an intermediate group who showed a more muted drop in liking with more sourness, and a strong positive group where liking increased with more sourness. Strikingly, both cohorts showed similar proportions of response patterns, with ~63-70 % in the strong negative group, and ~11-12 % in the strong positive group, suggesting these proportions may be stable across cultures. Notably, the three groups did not differ by age or gender. These data support the existence of different hedonic response profiles to sour stimuli in adults, once again highlighting the importance of looking at individual differences and potential consumer segments, rather than merely averaging hedonic responses across all individuals within a group.
... Moreover, PROP status has been also associated with fat taste sensitivity Melis, Sollai, Muroni, Crnjar, & Barbarossa, 2015;Tepper & Nurse, 1998). PROP status is then considered a general marker of oral responsiveness and it is often taken into account in studies aimed at investigating factors underlaying individual differences in food preferences and dietary habits (Bell & Tepper, 2006;Deshaware & Singhal, 2017;Dinehart, Hayes, Bartoshuk, Lanier, & Duffy, 2006;Duffy et al., 2010;Ervina et al., 2021;Kaminski, Henderson, & Drewnowski, 2000;Keller, Steinmann, Nurse & Tepper, 2002;Masi, Dinnella, Monteleone, & Prescott, 2015;Menghi et al., 2023;Mennella, Pepino, & Reed, 2005;Monteleone et al., 2017;Tepper, 2008, Tepper & Nurse, 1998Wijtzes et al., 2017;Yeomans, Tepper, Rietzschel, & Prescott, 2007). ...
Article
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Solutions and paper disks are widely used methods for classifying people by their ability to perceive 6-n-propylthiouracil (PROP). Recently, remote sensory testing carried out under the supervision of the panel leader, has been found to be a valid alternative to the traditional lab-setting, offering several practical advantages. This study aimed to validate a protocol for PROP status assessment in remote condition and to compare the results obtained using solutions and paper disks. Individual differences in bitterness responsiveness and the relative classification between two different testing conditions (remote and laboratory) and two stimuli (solutions and disks) were compared. 77 subjects (18-30 years; 60% women) participated in two sessions (one in laboratory and one in remote setting) and rated the perceived intensity of PROP solutions and disks. Mean PROP ratings did not vary across remote and lab conditions (p=0.844). PROP phenotype classifications in remote-solution and lab-disk conditions were comparable to lab-solution reference condition (with a misclassification rate of 27% and 31% respectively, all occurring within contiguous groups). In contrast, the classification in remote-disk condition was not fully comparable (misclassification in respect to lab-solution of 48% in contiguous groups, and 1.3% in non-contiguous groups). One-solution test appears as a reliable procedure for PROP status assessment in live remote testing. Also, impregnated paper disks represent a suitable alternative to solution testing in conventional lab setting for practical reasons. However, paper disks could represent a valid option for data collection outside the lab, but they require rigorous in-person control by the sensory personnel when used.
... This lends credence to the theory that variations in bitter sensitivity might result in both immediate preferences and long-term downstream consequences [3][4][5]. As a result, establishing the causes of variations in sensitivity and intake among people and groups can be performed by investigating the processes behind variance in bitter perception [6], [7]. A variety of complicated variables including age, gender, morphology and environment, interact to cause significant individual variances in bitter perception [8]. ...
Article
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Bitter substances are identified by protein receptors located on surface of taste cell membranes. Mutational polymorphism of the bitter taste receptor (TAS2R38) is a significant determinant in phenylthiocarbamide (PTC) threshold perception. This research objectives were to find TAS2R38 polymorphisms in Iraqi people and investigate any correlations between genotype and the PTC taste sensitivity. Bitterness sensitivity was determined by assessing the capacity to differentiate and the responsiveness to a representative strip of PTC. Cheek cells samples were collected for DNA extraction, PCR amplification and genotyping. PCR was performed to amplify the short region of the TAS2R38 gene containing the initial polymorphisms of interest (145G > C, rs713598). Amplified samples were digested by the restriction enzyme (HaeIII) to study the genetic variations in TAS2R38 which is involved in PTC bitter sensitivity. This particular study included a total of 32 different cohorts. The phenotypic frequency of PTC strong-tasters and non-tasters was identical at 34.375% which was a greater value than the frequency of weak-tasters (31.25%). While genotypic data analysis showed that weak-tasters had a genotypic frequency of 45.16% which was higher than the genotypic frequencies of strong-taters (22.58%) and non-tasters (32.26%) respectively. In addition to this, 87.1% of the projected phenotypic and genotypic frequencies were in agreement with one another. Even though more detailed statistical analysis with a bigger group is needed. The results of this study suggest that allelic variation in the single locus TAS2R38 rs713598 works as a crucial genetic marker for bitterness sensitivity and has vital roles in the bitter tasting ability among Iraqi population.
... Given that it is well documented that young adults as a group have a tendency to make unhealthy food choices which are convenient and that do not meet current dietary recommendations (Poobalan et al., 2014) this is a prime time for intervention to influence positive consumption. Another factor associated with low vegetable consumption is that some have unappealing sensory properties, such as bitter tastes (Dinehart et al., 2006). However, not all are identified in this way and some vegetable dishes could benefit with the addition of a flavoured dip to improve acceptance (Savage et al., 2013). ...
Article
Purpose Adequate vegetable consumption is fundamental to a healthy balanced diet; however, global compliance with recommendations is poor which is particularly important for young adults as they form food consumption habits. There is a growing interest in the circular economy of hospitality and sustainability of current dietary patterns in light of climate change and an expanding global population. The food value chain needs to be considered both vertically and horizontally where the research and development (R&D) investment is optimised by being “joined up” and not fragmentary; in addition, consumer trade-offs of health vs for example sensory appeal are taken into consideration. The purpose of this study was to identify factors predicting acceptance of vegetable dishes by young adults and present a roadmap that can be used for dish development and healthful marketing. Design/methodology/approach This study used the health belief model (HBM) as framework to investigate key factors that encourage vegetable intake by young adults using an online questionnaire sample of 444 enrolled in undergraduate programs at universities in Brazil. Findings Structural modelling showed that vegetable consumption frequency was positively influenced by Health concerns, Naturalness and Self-efficacy (including cooking skills), whereas Sensory factors and Familiarity demonstrated a negative loading that might be related to unpleasantness. Originality/value Globally, there is a strong need to promote the consumption of vegetables as a public health policy priority but also to ameliorate barriers to action that could be facilitated by availability, dish development and healthful marketing in hospitality operations.
... In general, people who are more sensitive to certain tastes tend to consume less of foods that exhibit that taste, while individuals with lower sensitivity to certain foods require stronger taste sensations or greater food intake to experience the same level of perception. 1 For example, individuals with a heightened sensitivity to bitter tastes may avoid certain vegetables that have a bitter taste, whereas those with lower sensitivity may consume these vegetables more easily. [2][3] Additionally, individuals with lower taste sensitivity may be more likely to consume unhealthy foods, such as those high in sugar or salt, 4 eating behavior associated with the onset of obesity, diabetes, and other health problems. 1 The magnitude of differences in the ability to detect certain tastes between individuals can range from 120-to 1000-fold in concentration. ...
Article
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Individuals vary in their ability to taste, and some individuals are more sensitive to certain tastes than others. Taste sensitivity is a predictor of various factors, such as diet, eating behavior, appetite regulation, and overall health. Furthermore, taste sensitivity can fluctuate within an individual over short to long periods of time: for example, in daily (diurnal) cycles, monthly (menstrual) cycles (in females), and yearly (seasonal) cycles. Understanding these temporal patterns is important for understanding individual eating habits and food preferences, particularly in the context of personalized and precision nutrition. This review provides a summary of the literature on taste sensitivity patterns across 3 temporal dimensions: daily, monthly, and yearly. Good evidence for diurnal patterns has been observed for sweet taste and fat taste, although the evidence is limited to rodent studies for the latter. Obese populations showed limited variation to sweet and fat taste sensitivities over a day, with limited variation in sweet taste sensitivity being linked to insulin resistance. There were mixed observations of temporal variation in sensitivity to sour and umami tastes, and there were no patterns in sensitivity to bitter taste. Menstrual patterns in sweet taste sensitivity were consistent with patterns in food intake. Other taste modality investigations had mixed findings that had little agreement across studies. Hormonal changes in females influence taste sensitivity to some degree, although the overall patterns are unclear. Seasonal patterns have been less well studied, but there is weak evidence that sweet, salty, and bitter taste sensitivities change across seasons. Differences in seasonal taste patterns have been observed in subgroups susceptible to mental health disorders, requiring further investigation. Patterns of taste sensitivity are evident across multiple temporal dimensions, and more research is needed to determine the influence of these patterns on food intake. Dysregulation of these patterns may also be a marker of certain diseases or health conditions, warranting further investigation. Notably, the alimentary tastes (umami, fat, and carbohydrate) are underrepresented in this research area and require additional investigation.
... Significant negative associations have been reported between responsiveness to solution of bitter, sour and astringent compounds and vegetable preference and intake (Louro et al., 2021;Pagliarini et al., 2021). Individuals more responsive to PROP also perceived greater bitterness and reported lower liking and intake for vegetables characterized by warning sensations and objectionable flavors (Dinehart et al., 2006;Duffy et al., 2020;Shen et al., 2016). Intricate interrelationships were found between bitterness and retro-nasal flavor sensations which negatively affect liking for green vegetables (Duffy et al., 2020) pointing out the complexity of real food perception. ...
... Traditional Chinese medicine believes that bitter compounds can relieve asthma, stop vomiting, promote defecation and have other effects [42,43]. At the same time, bitter taste is also indispensable in seasoning, as it can enrich or even improve the flavor of food when matched with other tastes [13,44]. Sweet and bitter tastes have a competitive inhibition relationship [19,20,37]. ...
Article
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Mulberry leaves are excellent for health care, confirmed as a ‘drug homologous food’ by the Ministry of Health, China. The bitter taste of mulberry leaves is one of the main problems that hinders the development of the mulberry food industry. The bitter, unique taste of mulberry leaves is difficult to eliminate by post-processing. In this study, the bitter metabolites in mulberry leaves were identified as flavonoids, phenolic acids, alkaloids, coumarins and L-amino acids by a combined analysis of the metabolome and transcriptome of mulberry leaves. The analysis of the differential metabolites showed that the bitter metabolites were diverse and the sugar metabolites were down-regulated, indicating that the bitter taste of mulberry leaves was a comprehensive reflection of various bitter-related metabolites. Multi-omics analysis showed that the main metabolic pathway related to bitter taste in mulberry leaves was galactose metabolism, indicating that soluble sugar was one of the main factors of bitter taste difference in mulberry leaves. Bitter metabolites play a great role in the medicinal and functional food of mulberry leaves, but the saccharides in mulberry leaves have a great influence on the bitter taste of mulberry. Therefore, we propose to retain bitter metabolites with drug activity in mulberry leaves and increase the content of sugars to improve the bitter taste of mulberry leaves as strategies for mulberry leaf food processing and mulberry breeding for vegetable use.
... Moreover, PTC or PROP sensitivity is associated with heightened intensity of prototypical tastants-such as sucrose and quinine-even after statistically removing the contribution of the TAS2R38 genotype [42][43][44]. Thus, bitter sensitivity to PTC or PROP and the TAS2R38 genotype may be of use as a marker of whole oral sensation [44][45][46][47]. ...
Article
Full-text available
Individual taste sensitivity influences food preferences, nutritional control, and health, and differs greatly between individuals. The purpose of this study was to establish a method of measuring and quantifying an individual's taste sensitivity and to evaluate the relationship between taste variation and genetic polymorphisms in humans using agonist specificities of the bitter taste receptor gene, TAS2R38, with the bitter compound 6-n-propylthiouracil (PROP). We precisely detected the threshold of PROP bitter perception by conducting the modified two-alternative forced-choice (2AFC) procedure with the Bayesian staircase procedure of the QUEST method and examined genetic variation in TAS2R38 in a Japanese population. There were significant differences in PROP threshold between the three TAS2R38 genotype pairs for 79 subjects: PAV/PAV vs AVI/AVI, p < 0.001; PAV/AVI vs AVI/AVI, p < 0.001; and PAV/PAV vs PAV/AVI, p < 0.01. Our results quantified individual bitter perception as QUEST threshold values: the PROP bitter perception of individuals with the PAV/PAV or PAV/AVI genotypes was tens to fifty times more sensitive than that of an individual with the AVI/AVI genotype. Our analyses provide a basic model for the accurate estimation of taste thresholds using the modified 2AFC with the QUEST approach.
... There is conflicting evidence for gender differences in the preference for sensory attributes of food. For instance, researchers found no significant differences in the perception of sweetness between women and men [45][46][47][48]. In contrast, evidence supporting differences in taste ratings between women and men has been reported [49,50]. ...
Article
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This study examined the gender-differentiated trait preferences of cooking banana (matooke) for farmers and consumers in Central Uganda to inform banana-breeding strategies. Women and men banana farmers might have differing production objectives, norms, and values which drive decisions on which varieties to adopt and grow. However, breeders rarely consider this in their variety development programs, leading to lost opportunities for equitable breeding. An exploratory sequential mixed-method approach was used to obtain a richer understanding of the trait preferences of women and men, which explains the acceptability of cooking bananas. Consumer preference tests for the candidate banana varieties and released hybrids were also conducted. The results showed that the universal attributes for variety selection were bunch size, taste, resistance to pests and diseases, drought tolerance, food texture/softness, maturity period, and finger size. Men appreciated agronomic and market-related traits, such as tolerance to drought and poor soils, bunch size and compactness, maturity period, and shelf life, while women valued processing and cooking traits such as flavour, food colour, ease of peeling, finger size, and agronomic traits such as plant height. These are plausible attributes for the gender-responsive breeding of bananas. The findings highlight the need to redesign the banana-breeding pipeline and process in Uganda to deliver varieties with attributes desired by women and men along this commodity value chain. A participatory demand-driven and gender-responsive process involving stepwise selection criteria that commences with quality traits followed by production traits while integrating gender-specific preferences should be employed to ensure the acceptability of cooking banana hybrids by women and men end users. This requires integrating different disciplines, including social scientists and gender experts, along the entire breeding process for more inclusive products and equitable outcomes.
... W analitycznych badaniach sensorycznych osoby kandydujące do zespołu osób oceniających (wybrani oceniający) powinny wykazywać wysoką i średnią wrażliwość sensoryczną. Osoby z niską wrażliwością sensoryczną nie są kwalifikowane do zespołu osób oceniających (Dinehart, Hayes, Bartoshuk, Lanier i Duffy, 2006;Kikut-Ligaj, 2014a, 2014b. ...
Book
Monografia jest kompleksowym opracowaniem naukowym obejmującym szereg istotnych kwestii związanych z jakością buraka ćwikłowego jako surowca będącego źródłem metabolitów wtórnych wpływających na jakość sensoryczną i zdrowotną produktów spożywczych. W monografii przedstawiono aktualny stan wiedzy na temat rynku warzyw w Polsce. Opisano przeprowadzone badania składu jakościowego buraków, stosując metody oparte na spektrometrii mas, które pozwoliły na zidentyfikowanie nowych, dotąd nieopisanych saponin triterpenowych w różnych odmianach buraków ćwikłowych oraz zmian ich zawartości w czasie obróbki termicznej surowca oraz przechowywania wyprodukowanych przetworów. Przedstawiono wpływ przetwarzania surowca i przechowywania gotowych przetworów z buraka na cechy sensoryczne, w tym smak słodki i gorzki. Wskazano rolę saponin triterpenowych jako antyoksydantów, zwiększających wartość prozdrowotną produktów otrzymanych z tego surowca. Wyznaczono kryteria doboru surowców w celu otrzymania produktu spożywczego o wysokiej jakości sensorycznej i właściwościach prozdrowotnych. Wskazano potencjał aplikacyjny różnych odmian buraka ćwikłowego pod względem ich przydatności do wyrobu produktów spożywczych spełniających oczekiwania konsumentów, którzy w obecnych czasach szczególną uwagę zwracają na cechy prozdrowotne i sensoryczne nabywanych produktów spożywczych. W monografii wyjaśniono wpływ substancji naturalnych buraka ćwikłowego na zdrowie. Rezultaty badań naukowych przedstawione w niniejszej monografii mają istotny wpływ na aktualny stan wiedzy i dalszy rozwój zagadnień związanych z jakością surowca i jego przetworów, głównie w kwestii zdrowotności i cech sensorycznych zwiększających popyt finalnego produktu. Rezultaty badań dostarczają producentom żywności istotnej wiedzy o możliwościach doboru odmiany buraka do rodzaju otrzymywanego produktu, co może się przyczynić do rozwoju przemysłu rolno-spożywczego.
... Among these are the density and activity of the fungiform papillae [40]. STs exhibit a higher density of fungiform taste papilla [30,[41][42][43] and a higher level of functional activity [40], as compared to MTs and NTs and this can explain why they are more sensitive to oral stimuli that are not mediated by the bitter TAS2R38 receptor [15,17,19,[21][22][23]28,[44][45][46][47][48][49][50][51]. These differences have found a mechanistic explanation in a polymorphism of the gene that codes for the salivary protein Gustin described as a taste bud trophic factor [40,52,53]. Taste sensitivity has also been linked to various other varying genes [54,55] or specific salivary amino acids and/or proteins [34,56,57]. ...
Article
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Several studies were focused on the genetic ability to taste the bitter compound 6-n-propylthiouracil (PROP) to assess the inter-individual taste variability in humans, and its effect on food predilections, nutrition, and health. PROP taste sensitivity and that of other chemical molecules throughout the body are mediated by the bitter receptor TAS2R38, and their variability is significantly associated with TAS2R38 genetic variants. We recently automatically identified PROP phenotypes with high precision using Machine Learning (mL). Here we have used Supervised Learning (SL) algorithms to automatically identify TAS2R38 genotypes by using the biological features of eighty-four participants. The catBoost algorithm was the best-suited model for the automatic discrimination of the genotypes. It allowed us to automatically predict the identification of genotypes and precisely define the effectiveness and impact of each feature. The ratings of perceived intensity for PROP solutions (0.32 and 0.032 mM) and medium taster (MT) category were the most important features in training the model and understanding the difference between genotypes. Our findings suggest that SL may represent a trustworthy and objective tool for identifying TAS2R38 variants which, reducing the costs and times of molecular analysis, can find wide application in taste physiology and medicine studies.
... Further, some researchers also believe that other factors that affect taste, such as aging and oral diseases, may also affect the sensitivity to PTC bitterness. However, the current evidence is limited, and more studies are required to fully elucidate this phenomenon [15,41,42]. Bartoshuk et al. reported gender differences in the perception of PTC bitterness, finding that women were more likely to perceive the bitterness of compounds such as PTC. ...
Article
Full-text available
Background The bitter taste receptor gene TAS2R38 is a member of the human TAS2R gene family. Polymorphisms in TAS2R38 affect the ability to taste the bitterness of phenylthiourea (PTC) compounds, thus affecting an individual’s food preference and health status. Methods We investigated polymorphisms in the TAS2R38 gene and the sensitivity to PTC bitterness among healthy Chinese college students in Hubei province. The association of TAS2R38 polymorphisms and PTC sensitivity with body mass index (BMI), food preference, and health status was also analyzed. A total of 320 healthy college students were enrolled (male: 133, female: 187; aged 18–23 years). The threshold value method was used to measure the perception of PTC bitterness, and a questionnaire was used to analyze dietary preferences and health status. Polymerase chain reaction (PCR) was used to analyze polymorphisms at three common TAS2R38 loci (rs713598, rs1726866, and rs10246939). Results In our study population, 65.00% of individuals had medium sensitivity to the bitterness of PTC; in contrast, 20.94% were highly sensitive to PTC bitterness, and 14.06% were not sensitive. For the TAS2R38 gene, the PAV/PAV and PAV/AAI diplotypes were the most common (42.19% and 40.63%, respectively), followed by the homozygous AVI/AVI (8.75%) and PAV/AVI (5.00%) diplotypes. Conclusion There was a significant correlation between the sensitivity to PTC bitterness and sex, but there was no correlation between the common diplotypes of TAS2R38 and gender. Polymorphisms in the TAS2R38 gene were associated with the preference for tea, but not with one’s native place, BMI, health status, or other dietary preferences. There was no significant correlation between the perception of PTC bitterness and one’s native place, BMI, dietary preference, or health status. We hope to find out the relationship between PTC sensitivity and TAS2R38 gene polymorphisms and dietary preference and health status of Chinese population through this study, providing relevant guidance and suggestions for dietary guidance and prevention of some chronic diseases in Chinese population.
... Differently from studies showing no differences in sweet taste perception between males and females [92][93][94][95], our results showed that the dose-dependent effect of gender was mostly observed in females, who give higher intensity ratings to the three higher concentrations of sucrose compared to males. It is interesting to note that females in our cohort have a lower BMI than males even though both were normal weight. ...
Article
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Individual differences in sweet taste sensitivity can affect dietary preferences as well as nutritional status. Despite the lack of consensus, it is believed that sweet taste is impacted by genetic and environmental variables. Here we determined the effect of well-established factors influencing the general taste variability, such as gender and fungiform papillae density, specific genetic variants (SNPs of TAS1R2 and TAS1R3 receptors genes), and non-specific genetic factors (PROP phenotype and genotype), on the threshold and suprathreshold sweet taste sensitivity. Suprathreshold measurements showed that the sweet taste response increased in a dose-dependent manner, and this was related to PROP phenotype, gender, rs35874116 SNP in the TAS1R2 gene, and rs307355 SNP in the TAS1R3 gene. The threshold values and density of fungiform papillae exhibited a strong correlation, and both varied according to PROP phenotype. Our data confirm the role of PROP taste status in the sweet perception related to fungiform papilla density, show a higher sweet sensitivity in females who had lower BMI than males, and demonstrate for the first time the involvement of the rs35874116 SNP of TAS1R2 in the sweet taste sensitivity of normal weight subjects with body mass index (BMI) ranging from 20.2 to 24.8 kg/m2. These results may have an important impact on nutrition and health mostly in subjects with low taste ability for sweets and thus with high vulnerability to developing obesity or metabolic disease.
Chapter
Large amounts of money, time and effort are devoted to sensory and consumer research in food and beverage companies in an attempt to maximize the chances of new products succeeding in the marketplace. Many new products fail due to lack of consumer interest. Answers to what causes this and what can be done about it are complex and remain unclear. This wide-ranging reference collates important information about all aspects of this in one volume for the first time. It provides comprehensive, state-of-art coverage of essential concepts, methods and applications related to the study of consumer evaluation, acceptance and adoption of new foods and beverages. Combining knowledge and expertise from multiple disciplines that study food sensory evaluation and consumer behaviour, it covers advanced methods including analytical, instrumental and human characterization of flavour, aspects of food processing and special research applications of knowledge and methods related to consumers’ evaluation of new food products. Researchers and professionals working in food science and chemistry are sure to find this an interesting read.
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Childhood and adolescence shape lifelong taste preferences and dietary habits, making them crucial periods for promoting healthy and sustainable eating. As students consume up to half of their daily energy intake at school, school interventions can have a significant impact on promoting plant‐based diets. Although the benefits of promoting plant‐based diets on children's and adolescents’ health and environmental sustainability are well established and various studies report promising effects of interventions based on sensory‐hedonic strategies and on nudging in promoting vegetables and pulses in schools, a comprehensive collection of those reports is lacking. Therefore, this systematic review aims to collect published literature on the above interventions in schools that focus on promoting the consumption of vegetables and pulses to children and adolescents. Three databases—PubMed, Scopus, and Web of Science—were searched over all years until March 2022 using pre‐specified terms. From the 10.488 studies identified, a total of 57 studies reporting sensory‐hedonic (e.g., manipulating food sensory properties or their hedonic value) or nudging (e.g., changing the presentation) interventions targeting children and/or adolescents in schools and aiming at promoting vegetables and/or pulses were included. Overall, interventions based on sensory‐hedonic strategies (either enhancing the perception of well‐accepted flavor and texture or manipulating their hedonic value) and on nudging (through incentives and prompts) are effective in promoting vegetables and pulses. A gap in the literature was identified for interventions targeting adolescents and promoting pulses. Finally, multicomponent interventions, rather than using one strategy alone, could be more successful.
Article
Objective: To examine the associations between bitter taste sensitivity, cruciferous vegetable consumption, and likelihood of obesity and diabetes among American adults. Research Design and Method: Cross-section observation of 2,129 adults...
Chapter
In the past, diagnosing and treating abnormalities of gustatory and olfactory perception presented several challenges, mainly because both normal and abnormal olfaction and gustation were little understood. Abnormalities can occur in primary disorders of smell or taste, or arise as a secondary effect of some other disease process. [1]KeywordsSmellTastePerceptionNutrientsEating
Article
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In healthy humans, taste sensitivity varies widely, influencing food selection and nutritional status. Chemosensory loss has been associated with numerous pathological disorders and pharmacological interventions. Reliable psychophysical methods are crucial for analyzing the taste function during routine clinical assessment. However, in the daily clinical routine, they are often considered too time-consuming. We used a supervised learning (SL) regression method to analyze with high precision the overall taste statuses of healthy controls (HCs) and patients with chemosensory loss, and to characterize the combination of responses that would best predict the overall taste statuses of the subjects in the two groups. The random forest regressor model allowed us to achieve our objective. The analysis of the order of importance of each parameter and their impact on the prediction of the overall taste statuses of the subjects in the two groups showed that salty (low-concentration) and sour (high-concentration) stimuli specifically characterized healthy subjects, while bitter (high-concentration) and astringent (high-concentration) stimuli identified patients with chemosensory loss. Although the present results require confirmation in studies with larger samples, the identification of such distinctions should be of interest to the health system because they may justify the use of specific stimuli during the routine clinical assessments of taste function and thereby reduce time and cost commitments.
Preprint
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In healthy humans, taste sensitivity varies widely, influencing food selection and nutritional status. Chemosensory reductions have been associated with numerous pathological disorders or pharmacological interventions. Reliable psychophysical methods are crucial resources to analyze the taste function during routine clinical assessment. However, in the daily clinical routine, they are often considered to be too time-consuming. We used the Supervised Learning (SL) regression method to analyze with high precision the overall taste status of healthy controls (HC) and patients with chemosensory loss and to characterize the combination of responses that best can predict the overall taste status of two groups. Random Forest regressor allowed us to achieve our objective. The analysis of the order of importance and impact of each parameter on the prediction of overall taste status in the two groups showed that salty (low concentration) and sour (high concentration) stimuli specifically characterized healthy subjects, while bitter (high concentration) and astringent (high concentration) stimuli identified patients with chemosensory loss. The identification of these distinctions appears to be of interest to the health system since they may allow the use of specific stimuli during routine clinical assessments of taste function reducing the commitment in terms of time and costs.
Article
Eating habits and genetic factors contribute to diseases such as obesity and Type 2 Diabetes Mellitus (T2DM). Variation in bitter taste perception has been linked with intake of alcohol, coffee, vegetable, and smoking habit as well as with adiposity, a risk factor for diabetes development. Therefore, it was hypothesized that bitter taste perception could lead to differences in eating/drinking behavior among individuals, which may lead T2DM development later in the life. Bitter taste sensitivity was assessed using paper strips having supra-threshold concentration of Phenyl Thio Carbamide (PTC). Lifestyle variables were assessed using standard anthropometry measurements and a questionnaire. T2DM risk was assessed using a point based system developed by Finnish Diabetes Association (FINDRISC score). SPSS software was used for statistical analysis. A total of 498 volunteers from New Delhi region participated in the present study, where the mean age of PTC tasters was 24 ± 12 years and for non-tasters was 29 ± 16 years. PTC taster status was significantly correlated with age (p ≤ 0.01), weight (p ≤ 0.05), BMI (p ≤ 0.05) and waste circumference (p ≤ 0.05). A positive correlation was observed for type of chocolate liking (r = 0.113, p ≤ 0.001) and for T2DM risk (p ≤ 0.012) with PTC non-taster status. Logistic regression analysis showed that PTC non-taster individuals are at a higher risk (OR: 1.558, 95% CI: 1.037-2.342, p=0.033) for developing T2DM in the next ten years. Present results have shown that bitter taste sensitivity modulates liking towards certain food and non-tasters for PTC have a higher BMI, weight and are at a higher risk for T2DM development. PTC tasting could be employed as a method for assessing risk of diabetes in healthy individuals. We recommend large scale screening among young adults to promote awareness and early prevention measures.
Article
Preference for vegetables is influenced by various factors, including demographic, psychological, socio-environmental, and genetic factors. This study confirmed that age, pickiness, and perceptual attributes were predictors of preference for vegetables and examined how preference for vegetables and their perceptual attributes varies with age and pickiness. Children (8-14 years, n = 420), youth (15-34 years, n = 569), middle-aged adults (35-64 years, n = 726), and older adults (65-85 years, n = 270) were asked which vegetables they liked (or disliked) and which perceptual attributes of each vegetable they liked (or disliked). On the basis of their responses, an overall preference score and a preference sub-score for each perceptual attribute were calculated. Participants in each age group were classified into four statuses (non-, mild, moderate, and severe) according to their pickiness scores. Multiple regression analysis revealed that age and preference sub-scores for eight perceptual attributes (sweetness, sourness, bitterness, umami, pungency, orthonasal aroma, texture, and appearance) were positive predictors of overall preference score and that pickiness score and four perceptual attributes (saltiness, astringency, retronasal aroma, and aftertaste) were negative predictors. In addition, overall preference score and preference sub-scores for perceptual attributes other than saltiness increased with increasing age group and decreasing picker status; however, preference sub-scores for at least one of the six perceptual attributes (bitterness, astringency, pungency, orthonasal aroma, retronasal aroma, and aftertaste) exhibited negative values in children, youth, and pickers (mild, moderate, and severe). The increase in preference for these perceptual attributes might be an indicator of the adultization of food perception and the expansion of food acceptance.
Article
In sensory evaluation, trained panelists are recommended to accurately assess complex flavors. However, many researchers assume that “simpler” qualities such as basic tastes can be reliably assessed by untrained individuals. In this work, we tested whether untrained participants would conflate the basic tastes of “bitter” and “sweet” with the hedonic aspects of an aroma by using Jelly Belly BeanBoozled® candies. These products are sweet candies which have either pleasant (e.g., coconut) or unpleasant (e.g., sour milk) aromas. In the first test, all participants rated candies with their nose open. In the second test, all participants rated candies with nose closed immediately followed by nose open. Both experiments demonstrated that sweetness was rated higher for good beans than bad beans and bitterness was rated higher for bad beans than good beans when rated with nose open. Closing the nose eliminated this difference, as all beans were actually sweet and not bitter. Researchers should use caution when interpreting sensory ratings from untrained participants, even for “simple” sensations such as basic tastes. While it is often necessary to use untrained participants, these individuals may conflate the hedonic aspects of the product with other sensory qualities.
Chapter
Disorders of smell, taste, and oral somatosensation (irritation, touch, temperature, pain) challenge the ability to consume safe and healthy diets as well as enjoy eating and food-related behaviors. From nationally representative US health monitoring, these disorders are as prevalent as hearing or vision disorders. Olfactory dysfunction is most common among older adults, although aging itself may not be the cause. Primary causes of olfactory dysfunction are sensorineural (e.g., chronic nasal/sinus disease, head trauma, respiratory tract infections) and neurodegenerative (e.g., Alzheimer’s disease). Less vulnerable to loss is taste, especially at levels experienced while eating. Individuals can suffer distorted or phantom sensations (i.e., dysgeusia) related to medications or conditions that disrupt normal interactions between cranial nerves that mediate taste sensation. Oral sensation (integrated taste, retronasal olfaction, and oral somatosensation) can be altered in systemic diseases (e.g., chronic kidney disease), especially if control is poor; by medications that treat and manage systemic diseases (e.g., cancer); and with poor oral health. Normal variation in taste associates with differences in food preferences and nutritional status, including obesity, while chemosensory disorders, if severe enough, can alter dietary patterns leading to weight gain or weight loss. Excessive alcohol consumption and chronic smoking increase the risk of chemosensory disorders directly or indirectly through exposures/conditions that, in turn, cause these disorders. Individuals with chemosensory disorders should have full medical evaluation, including assessment of the impact on eating behaviors, diet quality, and nutritional status. Access to healthcare and medical advances hold continued promise toward prevention and treatment of chemosensory disorders.
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The sensory properties of foods guide food choices and intake, importantly determining nutritional and health status. In communities that have inconsistent access to nutritious foods, such as food deserts, food taste perceptions and preferences have yet to be explored. The purpose of this study was to examine how taster status (supertaster vs. non-taster) and food security status (high or marginal vs. low or very low) influences food taste intensities, food preferences and perceptions, and diet quality in a cohort of students from a food desert campus in the Central Valley of California. Moreover, the complex relationship of socioeconomic status, race/ethnicity, and sex on cardiometabolic and cognitive health warrants further examination. Two hundred fifty participants (aged 18–24 years) living in a food desert campus were recruited in 2018 for this cross-sectional study where participants underwent taste tests on selected fruits, vegetables, and nuts, and clinical tests (anthropometrics, blood glucose, blood pressure, and endothelial function), cognitive function tests (memory and attention), diet quality assessment (Healthy Eating Index (HEI)), and food preference and perception assessments. Food taste intensities were influenced by sex with bitter and umami taste intensities of several foods being perceived more intensely by males. Moreover, food liking was largely influenced by ethnicity with Hispanics having higher liking ratings for several foods compared with non-Hispanics. Both, Hispanics and females, had higher total fruit HEI scores and lower attention scores than non-Hispanics and males, respectively. Females also had lower blood pressure, reactive hyperemia index, and fasting blood glucose. Food-insecure individuals rated cost and convenience as more important factors for overall food consumption and had lower attention scores than those with higher food-security status. Future research should consider the complex interactions of factors such as taste and flavor perception, sex, ethnicity, prior exposure to foods, and other environmental factors when studying food preferences and health in young adults.
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In the method of magnitude-matching, subjects try to judge intensities of sensations from two or more modalities on a single, common scale. Using responses to one modality as a standard makes it possible to compare subjects' suprathreshold perceptions on the other, test modality. A series of ten experiments revealed the following: (i) magnitude-matching 'works': with both loudness of tones and lightness of grays as standards, tasters versus nontasters of 6-n-prophylthiouracil (PROP) (as defined by a threshold criterion) show much greater responce to suprathreshold PROP and slightly greater response to surcose; (ii) though superior to rating-scale judgements of sensory intensity made without reference to a second modality, magnitude-matching is not, however, flawless: the cross-modality matching relation produced by a set of magnitude-matches depends systematically on the contextual sets of stimulus levels presented for judgement; (iii) with taste as the standard, old versus young subjects showed only a 25% decrement in responce to the odor intensity of butanol when both groups recieved the same physical (concentration) levels, but a >50% decrement in responce when both groups recieved about the same perceptual levels; (iv) magnitude-matches are much the same whether subjets make their judgements on a bounded rating-scale or an open-ended magnitude-estimation scale: and (v) loudness, lightness and odor intensity serve about equally in magnitude-matching with taste intensity.
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In five experiments, Sa were presented with a variety of sour and bitter compounds after the tongue was rinsed with distilled H20, QHCl, urea, or citric acid. All the acids tested were significantly less sour following adaptation to citric acid than after adaptation to distilled H2O. The taste of these acids was not affected by rinsing the tongue with QHCl or urea. QHCl adaptation markedly reduced the bitterness of some compounds, while having little effect on others, including urea and citric acid. Both urea and citric acid had smaller but reliable effects on the bitterness of QHCI. These apparently incompatible results do not seem to be the result of a simple verbal confusion between sourness and bitterness. Some compounds were not affected by any of the adapting conditions. The coding mechanisms for the sourness of acids appears to be relatively simple, while that for bitterness is more complex.
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Three lines of evidence from psychophysical experiments implied that mutual suppression of bitter and sweet tastes is due to neural inhibition rather than chemical interactions in solution or competition of molecules for common receptor sites. Removal of sweetness from bittersweet mixtures caused the bitterness to increase. This was accomplished by adaptation to sucrose or by treatment with Gymnema sylvestre, neither of which affect the concentration of sucrose on the tongue. Such increases in the bitterness of mixtures, independent of the concentration of the sweet masking substance, are difficult to reconcile with suppression by means of chemical interactions. Similar dependence of suppression on perceived intensity (and independence from concentration) was observed with mixtures of phyenylthiocarbamide and sucrose. Tasters of phenylthiocarbamide showed stronger suppression of sweetness than nontasters. This result was also inconsistent with molecular interactions causing suppression, which would have resulted in the same degree of suppression for the two groups. Instead, these findings support neural explanations of mixture suppression, such as antidromic inhibition or occlusion.
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The Labeled Magnitude Scale (LMS) is a semantic scale of perceptual intensity characterized by a quasi-logarithmic spacing of its verbal labels. The LMS had previously been shown to yield psychophysical functions equivalent to magnitude estimation (ME) when gustatory, thermal and nociceptive stimuli were presented and rated together, and the upper bound of the LMS was defined as the 'strongest imaginable oral sensation'. The present study compared the LMS to ME within the more limited contexts of taste and smell. In Experiment 1, subjects used both methods to rate either taste intensity produced by sucrose and NaC1 or odor intensity produced by acetic acid and phenyl ethyl alcohol, with the upper bound of the LMS defined as either the 'strongest imaginable taste' or the 'strongest imaginable odor'. The LMS produced psychophysical functions equivalent to those produced by ME. In, Experiment 2 a new group of subjects used both methods to rate the intensity of three different taste qualities, with the upper bound of the LMS defined as the 'strongest imaginable [sweetness, saltiness, or bitterness]'. In all three cases the LMS produced steeper functions than did ME. Experiment 3 tested the hypothesis that the LMS yields data comparable to ME only when the perceptual domain under study includes painful sensations. This hypothesis was supported when the LMS again produced steeper functions that ME after subjects had been explicitly instructed to omit painful sensations (e.g. the 'burn' of hot peppers) from the concept of 'strongest imaginable taste'. We conclude that the LMS can be used to scale sensations of taste and smell when they are broadly defined, but that it should be modified for use in scaling specific taste (and probably odor) qualities. The implications of these results for theoretical issues related to ME, category-ratio scales and the size of the perceptual range in different sensory modalities are discussed.
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To examine the self-reported importance of taste, nutrition, cost, convenience, and weight control on personal dietary choices and whether these factors vary across demographic groups, are associated with lifestyle choices related to health (termed health lifestyle), and actually predict eating behavior. Data are based on responses to 2 self-administered cross-sectional surveys. The main outcomes measured were consumption of fruits and vegetables, fast foods, cheese, and breakfast cereals, which were determined on the basis of responses to questions about usual and recent consumption and a food diary. Respondents were a national sample of 2,967 adults. Response rates were 71% to the first survey and 77% to the second survey (which was sent to people who completed the first survey). Univariate analyses were used to describe importance ratings, bivariate analyses (correlations and t tests) were used to examine demographic and lifestyle differences on importance measures, and multivariate analyses (general linear models) were used to predict lifestyle cluster membership and food consumption. Respondents reported that taste is the most important influence on their food choices, followed by cost. Demographic and health lifestyle differences were evident across all 5 importance measures. The importance of nutrition and the importance of weight control were predicted best by subject's membership in a particular health lifestyle cluster. When eating behaviors were examined, demographic measures and membership in a health lifestyle cluster predicted consumption of fruits and vegetables, fast foods, cheese, and breakfast cereal. The importance placed on taste, nutrition, cost, convenience, and weight control also predicted types of foods consumed. Our results suggest that nutritional concerns, per sc, are of less relevance to most people than taste and cost. One implication is that nutrition education programs should attempt to design and promote nutritious diets as being tasty and inexpensive.
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This study examined the relationship between various psychosocial factors and fruit and vegetable consumption. The 5 A Day Baseline Survey, conducted in August 1991, just before the initiation of the 5 A Day for Better Health Program, obtained data on adults' intakes of, and their knowledge, perceptions, and attitudes regarding, fruits and vegetables. The survey was conducted by telephone. Subjects were 2811 adults (response rate, 43%) aged 18 years and older in the 48 coterminous United States. Fruit and vegetable intake was measured as self-reported frequency of use; most of the psychosocial variables were measured using Likert scales. This study estimates that only 8% of American adults thought that five or more servings of fruits and vegetables were needed for good health. Of the factors studied, the most important in determining someone's fruit and vegetable intake were the number of servings they thought they should have in a day, whether they liked the taste, and whether they had been in the habit of eating many fruits and vegetables since childhood. These few factors accounted for 15% more of the variation in fruit and vegetable consumption than did demographic variables alone (8%). Nutrition education should stress the need to eat five or more servings of fruits and vegetables per day because few adults are aware of this recommendation and such knowledge is strongly associated with increased intake. Furthermore, efforts to increase the palatability of fruits and vegetables, especially among children, should be promoted.
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It is generally assumed that the mutual, but asymmetric, suppression of the components in binary taste mixtures is an invariant property of the human psychophysical response to such mixtures. However, taste intensities have been shown to vary as a function of individual differences in sensitivity, indexed by the perceived bitterness of 6-n-propylthiouracil (PROP). To determine if these variations in taste perception influence taste mixture interactions, groups of PROP super-, medium- and non-tasters assessed four binary taste mixtures: sweet-bitter [sucrose/quinine hydrochloride (QHCl)], sweet-sour (sucrose/citric acid), salty-bitter (NaCl/QHCl) and salty-sour (NaCl/citric acid). In each experiment, subjects received factorial combinations of four levels of each of two tastants and rated individual taste intensities and overall mixture intensity. For each taste quality, super-tasters typically gave higher ratings than either medium- or non-tasters, who tended not to differ. There were also group differences in the interactions of the mixtures' components. Super-tasters rated the overall intensity of the mixtures, most likely reflecting integration of the taste components, as greater than medium- and non-tasters, who again showed few differences. In sweet-bitter mixtures, non-tasters failed to show the suppression of sweetness intensity by the highest QHCl concentration that was evident in super- and medium-tasters. These data show that the perception of both tastes and binary taste mixture interactions varies as a function of PROP taster status, but that this may only be evident when three taster groups are clearly distinguished from one another.
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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.
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Principles for reporting analyses using structural equation modeling are reviewed, with the goal of supplying readers with complete and accurate information. It is recommended that every report give a detailed justification of the model used, along with plausible alternatives and an account of identifiability. Nonnormality and missing data problems should also be addressed. A complete set of parameters and their standard errors is desirable, and it will often be convenient to supply the correlation matrix and discrepancies, as well as goodness-of-fit indices, so that readers can exercise independent critical judgment. A survey of fairly representative studies compares recent practice with the principles of reporting recommended here.
Article
Alcohol produces a range of oral sensations, some of which have been shown to vary with the perceived bitterness of 6-n-propylthiouracil (PROP), one marker for genetic variation in taste. Some studies report that offspring of alcoholics are most likely to be PROP nontasters [Physiol. Behav. 51 (1992) 1261; Physiol. Behav. 64 (1998) 147], yet others report the offspring as more responsive to sodium chloride (NaCl) and citric acid, which appears to contradict the taste genetic hypothesis. We predicted alcohol sensation and intake from measures of taste genetics (PROP bitterness and number of fungiform papilla), NaCl and citric acid intensity, and spatial taste pattern in 40 females and 43 males. Subjects used the general Labeled Magnitude Scale (gLMS) [Chem. Senses 18 (1993) 683; J Food Qual. Pref 14 (2002) 125] as an intensity and hedonic scale. Those who tasted PROP as most bitter or had highest numbers of fungiform papilla reported greatest oral burn from an alcohol probe; those who tasted least PROP bitterness consumed alcoholic beverages most frequently. Although higher NaCl and citric acid ratings associated with more frequent consumption of alcoholic beverages, the findings could be explained by lower intensity of tastants on the tongue tip (chorda tympani nerve) relative to whole mouth perception. In multiple regression analyses, PROP bitterness and the spatial pattern of taste perception were independent contributors to the prediction of alcohol intake. In summary, the results support that variation in oral sensation associates with alcohol intake. Those who taste PROP as least bitter and have low chorda tympani relative to whole mouth taste intensity appear to have fewest oral sensory hindrances to the consumption of alcoholic beverages.
Article
A series of experiments investigated the nature of metallic taste reports and whether they can be attributed to the development of a retronasal smell. Two studies showed that the metallic sensation reports following oral stimulation with solutions of FeSO4 were reduced to baseline when the nose was occluded. No such reduction was seen for CuSO4 or ZnSO4, which were more bitter and astringent, respectively, and less metallic. A discrimination test based on weak but equi-intense levels of FeSO4 and CuSO4 showed that FeSO4 could be discriminated from water with the nose open but not when occluded, but that discrimination of CuSO4 from water was not impaired by nasal occlusion. A discrimination test demonstrated that the headspace over solutions of FeSO4 was not different from water, although some subjects could discriminate FeSO4 solutions from water in the mouth when the nose was occluded, perhaps by tactile or astringent cues. These results confirm that metallic taste reports following oral stimulation with FeSO4 are likely due to development of a retronasal smell, possibly following a lipid oxidation reaction in the mouth. However, metallic taste reports may arise from different mechanisms with copper and zinc salts.
Article
Bitter taste perception provides animals with critical protection against ingestion of poisonous compounds. In the accompanying paper, we report the characterization of a large family of putative mammalian taste receptors (T2Rs). Here we use a heterologous expression system to show that specific T2Rs function as bitter taste receptors. A mouse T2R (mT2R-5) responds to the bitter tastant cycloheximide, and a human and a mouse receptor (hT2R-4 and mT2R-8) responded to denatonium and 6-n-propyl-2-thiouracil. Mice strains deficient in their ability to detect cycloheximide have amino acid substitutions in the mT2R-5 gene; these changes render the receptor significantly less responsive to cycloheximide. We also expressed mT2R-5 in insect cells and demonstrate specific tastant-dependent activation of gustducin, a G protein implicated in bitter signaling. Since a single taste receptor cell expresses a large repertoire of T2Rs, these findings provide a plausible explanation for the uniform bitter taste that is evoked by many structurally unrelated toxic compounds.
Article
A scale of oral sensation was constructed by having subjects rate the perceptual magnitudes of semantic descriptors (e.g. 'weak', 'strong') within the context of imagined gustatory and somesthetic sensations (e.g. 'the sweetness of banana', 'biting the tongue'), then arranging the descriptors according to their mean perceptual intensities. The resulting scale, which we refer to as the oral labeled magnitude scale (LMS), is characterized by a non-linear spacing among its verbal descriptors that, like Borg's (1982) category-ratio scale, is roughly logarithmic. The LMS was evaluated by comparing it with the method of magnitude estimation in an experiment in which subjects rated the intensity of sensations of sweetness, chemical irritation and cold. The psychophysical functions produced by the two methods were not statistically different, indicating that the oral LMS yielded ratio-level data comparable to that produced by magnitude estimation. A final experiment demonstrated the importance of the spacing among semantic descriptors by showing that both the psychophysical functions and the semantic information about perceptual intensity were altered when the descriptors were equally spaced. Theoretical and practical issues related to the empirical approach to scale construction and the generality and robustness of the oral LMS are discussed.
Article
Reviews the books, Using LISREL for structural equation modelling: A researcher’s guide and Principles and practice of structural equation modelling by E. Kevin Kelloway (see record 1998-08130-000) and Principles and practice of structural equation modelling by Rex B. Kline (see record 1998-02720-000). Structural equation modeling (SEM) is one of the most rapidly growing analytic techniques in use today. Proponents of the approach have virtually declared die advent of a statistical revolution, while skeptics worry about the widespread misuse of complex and often poorly understood analytic methods. The two new books under review are therefore timely. Both are valuable, but differ in important ways. Kevin Kelloway's book is directed at the researcher with little knowledge of structural equation modeling and is intricately linked to one of the more popular structural equation modeling programs, LISREL. For researchers keen to begin analyzing data quickly, this book is an invaluable resource that will speed one's introduction to SEM. On the other hand, the volume written by Rex Kline represents one of the most comprehensive of available introductions to the application, execution, and interpretation of this technique. The book is written for both students and researchers who do not have extensive quantitative background. It is especially attentive to quantitative issues common to most structural equation applications. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Taste and oral sensations from foods and beverages drive food selection. The present study explored whether markers of variation in taste were associated with variability in sweet sensation, sweet preference, and intake of added sugar. Following the pioneering work of Fischer and colleagues from the 1960s, variation in taste was described using the bitterness of 6-n-propylthiouracil (PROP) and that of quinine hydrochloride (QHCl). These markers represent variation in taste, resulting from genetic and environmental influences. In 38 females and 44 males, those who tasted PROP as least bitter but QHCl as most bitter reported the greatest preference for and intake of added sugars (reported frequency of consuming high added sugar foods or percent energy from added sugar). Individuals who were discordant in the PROP versus QHCl bitterness showed most variance in sweet preference and intake. These findings suggest that genetic and environmental variation in taste influences dietary behaviors toward sweet foods. Dietetics practitioners can apply this information by assessing dietary preferences and assisting individuals who prefer sweet foods and beverages to incorporate them into healthful and enjoyable diets.
Article
Article
Genetic sensitivity to the bitter taste of 6-n-propylthiouracil (PROP) has been linked with a greater number of food aversions and reported rejection of some bitter foods. Healthy young women (n= 121) were divided into nontasters, tasters and supertasters of PROP according to their PROP detection thresholds and the ratio of intensity ratings of PROP versus NaCl solutions. Hedonic response profiles to sucrose solutions distinguished between likers and dislikers of sweet. All subjects completed a 171-item food preference checklist. Food preference data were reduced by factor analyses, subscales of which were tested for reliability using Cronbach's alpha. Greater PROP sensitivity was associated with lower acceptance of coffee, cruciferous vegetables, tart citrus fruit, dark breads, and selected fats. In contrast, liking for sucrose solutions was linked to liking for sugar in tea and coffee, but not to any special pattern of food acceptance. Strategies aimed at increasing the consumption of grains, vegetables, and fruit should consider the role of inherited taste markers and their potential impact on dietary habits.
Article
Direct comparisons of sensory or hedonic perceived intensities across individuals are impossible since we cannot share experiences. However, experiences can be compared indirectly if we can identify a standard assumed to be equal, on average, to groups compared. Sensory standards (i.e., magnitude matching) have proved very useful. Intensity adjectives/adverbs have also been used as standards (e.g., This tastes very strong to me; is it very strong to you?). We argue these labels often refer to experiences of different absolute intensity to the groups of interest making the comparisons invalid. An early solution rested on the assumption that the maximum intensity perceivable was equal for all sensory domains and individuals. Comparisons were then possible because all judgments could be made on a zero to maximum scale. We present data showing this assumption is not true.
Article
Topical application of miracle fruit (Synsepalum dulcificum) caused subsequently tasted hydrochloric and citric acids to taste less sour than normal and as if they had been sweetened. Gymnema sylvestre abolished this sweetness and returned the sourness of both acids to approximately their normal intensities although Gymnema sylvestre alone did not significantly affect the taste of the acids. This suggests that miracle fruit adds sweetness to acids without directly blocking sour receptor sites. When sugar was added to citric acid to make it about as sweet as it was after miracle fruit, then the sourness was suppressed in the mixture just as sourness was suppressed by miracle fruit. This suggests that the reduction in sourness after miracle fruit resulted from mixture suppression, i.e., the mutual suppression usually observed between different qualities in a mixture. When several acids were matched in sourness they did not become equally sweet after miracle fruit.
Article
This paper reports a procedure, like classical conditioning, that produces enhancement of liking for flavors by humans. The procedure is “pairing” of a relatively neutral flavor with sugar (a hedonically positive taste). Specifically, subjects drank 24 small samples of flavor A sweetened and 24 small samples of flavor B unsweetened. They were then tested for their liking for flavors A and B, both sweetened and unsweetened. In three different studies, varying in a number of aspects of stimulus presentations and context, a relative enhancement in liking for flavor A appeared both on the day of exposure and 1 week later. An absolute enhancement in liking of flavor B (a “mere exposure” effect) also occurred in two of the three experiments.
Article
Four experiments investigated the possibility of a taster-nontaster dimorphism for creatine and creatinine, and whether perception of these substances was related to sensitivity to phenylthiocarbamide (PTC). Threshold measurements, suprathreshold scaling of perceived intensity, a cross-adaptation experiment and a category scaling task produced consistent results. No relation to PTC was observed. In contrast to previous reports, no evidence of a taster-nontaster effect for creatine or creatinine was found. Creatine was a notably ineffective taste stimulus for all subjects tested.
Article
Bitter taste thresholds for 6-n-propylthiouracil are bimodally distributed, dividing subjects into tasters and nontasters. Their taste worlds differ with regard to the sweetness of sucrose and saccharin and to the bitterness of saccharin. These differences suggest that nontasters tend to perceive less bitterness in saccharin at concentrations used in beverages.
Article
Human subjects rated the perceived intensity and pleasantness of taste mixtures (sucrose-quinine) and odor mixtures (lemon-heptanal or pyridine-lavender). The components of the mixture were judged as less intense when mixed than when judged alone. A multiple regression indicated that the pleasantness of a mixture can be predicted from a weighted additive function of the pleasantness values of the component sensations. Pleasantness values of the componetns had to be estimated from their pleasantness-intensity functions, because the perceived intensities of the components change when the components are combined. Weighting coefficients for the linear regressions were greater for the unpleasant components, especially in the odor mixtures.
Article
Bitter tasting compounds in cruciferous vegetables resemble chemically the compound phenylthiocarbamide (PTC). As sensitivity to PTC is genetically mediated, it was hypothesized that this characteristic would be linked to greater sensitivity of the bitter tasting components in cruciferous vegetables, and that PTC sensitivity would be reflected in less favourable sensory perceptions and lower use of the vegetables. PTC status was determined for healthy, racially and culturally similar women, alike in foodways and aged 18-46 years. The frequency of use and perceptions of sensory, post-ingestional and social attributes of 11 cruciferous and two non-cruciferous vegetables in both raw and cooked forms were compared between the PTC tasters and non-tasters. Minimal effects of PTC status on these factors were observed. Only two vegetables showed significant differences in use--PTC non-tasters used cooked turnip and raw watercress significantly more than did PTC tasters. Perceived bitter taste and aroma did not offer an explanation for the findings. Similarly, familiarity, early exposure, and tolerance did not account for any group differences. PTC status, especially in terms of non-tasting propensity, may have some sensory-specific effects which will impact on the use of cruciferous vegetables by young and mature women, but environmental factors may offset this effect and must be considered in studies of food behaviour.
Article
Confusions between bitterness and acidity in the perception of three taste stimuli - quinine sulphate, citric acid and disodium-5î-guanylate - were examined over the near-threshold range in 45 subjects, using an extended ascending series procedure and intensity ratio estimations. Individual differences, and the effects of reference information, were marked. The results are interpreted in terms of a cosine model of qualitative confusions.
Article
Many subjects cannot identify sour and bitter solutions which they can clearly taste. Subjects show a great deal of agreement on the taste of predominantly sweet and predominantly salt substances, but much less agreement on predominantly bitter and predominantly sour substances. The argument is put forward that we do not easily learn the sour/bitter distinction because few food substances taste strongly bitter. Because bitter has an unpleasant connotation a large minority tends to use it wrongly for substances that are unpleasantly sour.
Article
Individuals who have sustained considerable damage to parts of the taste system often fail to experience changes in everyday taste experience. The two halves of the tongue are independently innervated: the chorda tympani (branch of the facial or VIIth cranial nerve) innervating the anterior two-thirds and the glossopharyngeal (IXth cranial nerve) innervating the posterior one-third. Anesthesia of the chorda tympani nerve on one side produced increased taste intensities for some stimuli on the area innervated by the glossopharyngeal nerve on the other side. Because this effect occurs across the midline and taste projects ipsilaterally, the effect must occur in the central nervous system (CNS). This supports Halpern and Nelson's release-of-inhibition hypothesis that the area to which the chorda tympani projects in the CNS must normally inhibit that of the glossopharyngeal nerve. Anesthesia of the chorda tympani abolishes that inhibition and leads to perception of increased taste intensities from areas innervated by the glossopharyngeal nerve.
Article
Taste worlds of humans vary because of taste blindness to phenylthiocarbamide (PTC) and its chemical relative, 6-n-propylthiouracil (PROP). We review early PTC studies and apply modern statistical analyses to show that a higher frequency of women tasted PTC crystals, and were tasters (threshold classification). In our laboratory, scaling of PROP bitterness led to the identification of a subset of tasters (supertasters) who rate PROP as intensely bitter. Supertasters also perceive stronger tastes from a variety of bitter and sweet substances, and perceive more burn from oral irritants (alcohol and capsaicin). The density of taste receptors on the anterior tongue (fungiform papillae, taste buds) correlate significantly with perceived bitterness of PROP and support the supertaster concept. Psychophysical data from studies in our laboratory also show a sex effect; women are supertasters more frequently. The anatomical data also support the sex difference; women have more fungiform papillae and more taste buds. Future investigations of PTC/PROP tasting and food behaviors should include scaling to identify supertasters and separate sex effects.
Article
Patients with localized damage to the taste system often experience no subjective change in real-world taste experience. In an effort to understand this, eight patients who recently underwent acoustic neuroma removal were evaluated for taste loss. Localized taste testing showed that taste intensities decreased in the distribution of cranial nerve VII ipsilateral to tumor removal as expected, but asymmetries occurred for IX. Intensities were greater on the side contralateral to the tumor removal. In addition, palatal taste, also thought to be mediated by VII, was not totally abolished. It is concluded that cranial nerve IX is normally inhibited by cranial nerve VII in the taste network. When VII is damaged, this inhibition is abolished. This release of inhibition serves as a compensation mechanism that preserves normal taste experience.
Article
Family studies using thresholds showed that PROP (6-n-propylthiouracil) tasting is produced by a dominant allele, T. Nontasters have two recessive alleles and tasters have one or two dominant alleles. The bitterness of suprathreshold PROP and anatomical criteria subdivide tasters into medium and supertasters. Supertasters may be TT tasters, but this has yet to be demonstrated. Supertasters preceive the greatest bitterness and sweetness from many stimuli as well as the greatest oral burn from alcohol and capsaicin. Women are more likely than men to be supertasters. Otitis media and head trauma can alter taste and thus PROP classifications, complicating studies on PROP genetics. Some subjects with a history of otitis media show taste reductions, but others show enhanced tastes and appear to have more taste buds per fungiform papilla. Subjects with head trauma show reduced tastes on some oral loci, but there is evidence that severe reductions on the front of the tongue ameliorate reductions at the circumvallate papillae on the back of the tongue by a release of inhibition mechanism.
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In this review of the scientific literature on the relationship between vegetable and fruit consumption and risk of cancer, results from 206 human epidemiologic studies and 22 animal studies are summarized. The evidence for a protective effect of greater vegetable and fruit consumption is consistent for cancers of the stomach, esophagus, lung, oral cavity and pharynx, endometrium, pancreas, and colon. The types of vegetables or fruit that most often appear to be protective against cancer are raw vegetables, followed by allium vegetables, carrots, green vegetables, cruciferous vegetables, and tomatoes. Substances present in vegetables and fruit that may help protect against cancer, and their mechanisms, are also briefly reviewed; these include dithiolthiones, isothiocyanates, indole-3-carbinol, allium compounds, isoflavones, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, vitamin C, D-limonene, lutein, folic acid, beta carotene, lycopene, selenium, vitamin E, flavonoids, and dietary fiber. Current US vegetable and fruit intake, which averages about 3.4 servings per day, is discussed, as are possible noncancer-related effects of increased vegetable and fruit consumption, including benefits against cardiovascular disease, diabetes, stroke, obesity, diverticulosis, and cataracts. Suggestions for dietitians to use in counseling persons toward increasing vegetable and fruit intake are presented.
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The chorda tympani nerve innervates the anterior two-thirds and the glossopharyngeal nerve, the posterior one-third, of each side of the tongue. Previous work showed that anesthesia of one chorda tympani increased the perceived intensity of quinine applied to an area innervated by the contralateral glossopharyngeal nerve, but decreased the perceived intensity of NaCl applied to an area innervated by the ipsilateral glossopharyngeal nerve. The data presented here corroborate that earlier finding and show that if both chorda tympani nerves are anesthetized, the taste of quinine is intensified and the taste of NaCl diminished at areas innervated by the glossopharyngeal on both sides of the tongue. In about 40% of the subjects, tastes occurred in the absence of stimulation (we call these tastes phantoms). The phantoms were usually localized to the posterior tongue contralateral to the anesthesia and they were abolished when a topical anesthetic was applied to the area where they were perceived. Phantoms like these may be a source of clinical dysgeusia in patients with localized taste damage. The phantoms may result because the anesthesia releases inhibition normally occurring between the central projection areas of different taste nerves.