Exploring the effects of genotypical and phenotypical variations in bitter taste sensitivity on perception,liking and intake of brassica vegetables in the UK

Brassicaceous vegetables (BV) have chemoprotective effects and yet consumption of BV in the UK is low. Previous studies suggest perception, liking and intake of BV are influenced by bitter taste sensitivity which this study further explores. Phenotypical taste sensitivity of 136 subjects was classified using propythiouracil (PROP) and sodium chloride and fungiform papillae density (FPD) was measured from tongue images. Polymorphisms of TAS2R38 and gustin (CA6) genes were analysed. Liking and bitterness of four raw vegetables (two BV (broccoli and white cabbage) and two non-BV (spinach and courgette)), as well as habitual consumption, were evaluated.There was a significant association between TAS2R38 genotype and PROP taster status (p < 0.0001) and between FPD and PROP taster status (p = 0.029). Individuals with greater sensitivity for PROP predominantly had TAS2R38 PAV/PAV genotype and greater FPD. BV were perceived as more bitter than non-BV (p < 0.0001) with PAV/PAV subjects perceiving significantly stronger bitter intensity. There was a significant difference in liking for the four vegetables (p = 0.002), and between consumers of different TAS2R38 genotype (p = 0.0024). Individuals with TAS2R38 AVI/AVI genotype liked BV more. Regarding intake, both PAV/PAV and AVI/AVI individuals consumed more total vegetables and BV than PAV/AVI. Although PROP nontasters tended to consume more vegetables and BV than the other two phenotype groups, liking and vegetable intake were not significantly affected by taste phenotype. Although there was not a significant effect of CA6 genotype on bitterness ratings, there was a significant interaction between CA6 and TAS2R38, and in addition CA6 genotype was significantly associated with BV intake. However, these effects require validation as the proportions of the population with the CA6 G/G genotype was extremely small (7%).Our results confirmed that bitter taste perception in vegetables was influenced by both genotype and phenotype of bitter taste sensitivity. Moreover, our findings demonstrated that neither genotype nor phenotype of taste sensitivity alone accurately predict vegetable liking and intake as demographic factors were found to have a substantial influence.     

Genetic and environmental influences on liking and reported intakes of vegetables in Irish children

Variation in the bitterness of 6-n-propylthiouracil (PROP) is partially explained by polymorphisms in the TAS2R38 gene. Based on their perception of bitterness from PROP, people may be classified into non-, medium and supertasters. PROP perception has previously been linked to liking for cruciferous vegetables in children in some studies, but only one study to date has examined TAS2R38 genotype and its relationship with vegetable intake in children. Children’s vegetable consumption generally does not meet the recommended guidelines, thus the present study aimed to examine the influence of oral sensory measures, genetic variation and social factors on vegetable liking and intake. Vegetable liking in 7–13 year old Irish children (n = 525) was measured on a 5-point liking scale, and dietary intakes were assessed via a 3-day diet history. Vegetable intakes were calculated and standardised per kg body weight. A subset of children (n = 485) were genotyped for SNPs in TAS2R38, (A49P, V262A, I296V), and fungiform papilla (FP) were counted. The bitterness of PROP and sweetness of sucrose were rated on a generalised labelled magnitude scale (gLMS). PROP and sucrose intensity were significantly correlated (R² = 0.33, p = 0.001), although neither sucrose intensity nor FP density differed across the TAS2R38 genotype groups. Supertasters were less likely than nontasters to have tried/tasted cruciferous vegetables p < 0.04). A small, positive correlation was seen in FP density and vegetable intake, but only in the AVI homozygous children, (R² = 0.17, p = 0.035). 174 Nutrient acceptable children reported an intake of one or more of the vegetables of interest in the 3-day period. Liking of cruciferous vegetables and reported intake were significantly correlated. In multiple regression analyses in this subsection of the cohort, socioeconomic status (SES) and gender were more important than PROP bitterness or TAS2R38 genotype in predicting intakes (approximately 15% of liking and 67% of intake was explained by these models). Overall, neither PROP taster status nor TAS2R38 genotype alone had significant impact on bitter vegetable liking or intake. Further research into FP density and vegetable liking and intake may be warranted.     

Sensory profile,acceptability, and their relationship for diabetic/reduced calorie chocolates

The purpose of this study was to determine the sensory properties and acceptability of lab developed prototypes of conventional, diabetic (with no sugar), and diabetic/reduced calorie milk chocolates (no sugar and 25% calorie reduction) with high-intensity sweeteners, sucralose and stevioside, and partial fat replacement with whey protein concentrate (WPC). PLS was performed in order to relate sensory properties and consumer acceptability and to determine drivers of liking and disliking. There was no difference between conventional, diabetic and diabetic/reduced calorie milk chocolates for brightness, cocoa aroma, cocoa butter aroma, and cocoa flavor (p > 0.05). Acceptability was higher for sucrose substitution by sucralose than by stevioside and partial fat replacement reduced acceptability of flavor even more (p ? 0.05). Crucial attributes which determine consumer acceptability in samples are sweet aroma, melting rate, and sweetness, whereas bitterness, bitter aftertaste, adherence, and sandiness were drivers of disliking.     

Caffeine metabolism rate influences coffee perception,preferences and intake

Several factors – genetic, demographic and environmental – contribute to individual differences in sensitivity to the pharmacological effects of caffeine. Caffeine metabolism influences coffee consumption, but its effect on bitterness perception in, and preference for, coffee is unknown.This study explores the possible relationship between caffeine metabolism rate and coffee preferences and consumption habits. In addition, the extent to which caffeine metabolism interacted with variations in bitterness perception was investigated. Caffeine metabolism rate was assayed by competitive immuno-enzymatic assay in one-hundred thirty-five coffee consumers who provided saliva samples after 12 h caffeine abstinence and at 30 and 90 min after ingestion of caffeine (100 mg). A caffeine metabolism index (CmI) was computed as the ratio between the amount of residual caffeine in saliva 60 min after the adsorption peak and the amount of caffeine at the adsorption peak corrected with the baseline. Ninety-one subjects were selected to investigate the relationships between inter-individual variation in caffeine metabolism, bitterness perception and coffee preference. Subjects rated liking for, and sourness, bitterness and astringency of, six unsweetened and freely sweetened coffee samples varying in roasting degree, caffeine content and bitterness. They also rated the bitterness of six caffeine and six quinine (equi-intense) solutions. Finally, subjects choose coffee to drink on the basis of a label (strong vs balanced flavor) both after caffeine abstinence and after no restrictions on caffeine intake. The CmI was strongly associated with the frequency of daily coffee consumption. Subjects with lower CmI gave higher bitterness ratings than other subjects for both coffee and caffeine solutions, but not for quinine solutions. They also added more sugar to the coffee samples. Following caffeine abstinence, all subjects chose the “strong flavor” coffee, while without caffeine restrictions, subjects with lower CmI preferentially tended to choose the “balanced flavor” coffee. These results provide the first link between caffeine metabolism and bitterness perception, and to the use of sugar to modify coffee bitterness.     

Lingonberry (Vaccinium vitis-idaea L.) grown in the Pacific Northwest of North America: Anthocyanin and free amino acid composition

Lingonberries and their products are popular and generally accessible in Europe, though in the US they are uncommon and considered a minor berry/fruit crop. The on-going interest in potential health benefits from berry consumption has heightened interest in broadening the selection of berry/fruit crops in the US. This study measured total phenolics, total tannins, complete anthocyanin content, and total (and individual) free amino acid composition for each of five lingonberry cultivars. Cultivars Ida, Koralle, Linnea, Sanna, and Sussi were grown in Oregon, USA, and had only been evaluated previously for their horticultural traits. All five cultivars contained the three anticipated anthocyanins (by HPLC): cyanidin-3-galactoside (main anthocyanin found in these berries), cyanidin-3-glucoside, and cyanidin-3-arabinoside. These lingonberries’ total anthocyanin content ranged from 27.4 (‘Linnea’) to 52.6 (‘Ida’) mg/100 g fw. They contained 22 free amino acids (FFAs) and total FAAs ranged from 28.92 (‘Sanna’) to 70.38 (‘Koralle’) mg/100 g fw. Asparagine (ASN) was the leading FAA (22–34% of the total FAAs) for all five cultivars. This is the first report on lingonberry FAA content.     

Exploring the hedonic and incentive properties in preferences for bitter foods via self-reports,facial expressions and instrumental behaviours

Preferences for and consumption of bitter foods such as vegetables and fruit are important in addressing the epidemic of obesity as healthy dietary patterns contribute to its prevention. However, few studies have been undertaken to understand the preference for bitter-tasting foods. A generally accepted but not proven explanation is that these acquired preferences involve changes in affective and motivational processes in order to overcome the innate rejection of bitter tastes. To examine this issue we compared the hedonic and incentive responses to bitter substances among bitter likers and dislikers. In addition, the effects of hunger, stress and weight concern on bitter preferences were also explored. Fifty-nine healthy adults (age = 24.8 ± 6.3; body mass index = 22.0 ± 2.8) were divided into bitter likers and bitter dislikers according to their food preferences. Both groups sampled the unreinforced flavours of coffee, beer, chocolate and grapefruit under four motivational states induced by static pictures (neutral, food, stressor and obesity) at the time of testing. The results showed that the bitter solutions elicited less aversive responses (higher hedonic ratings and less intense disgust reactions) and fewer avoidance behaviours (slower response time and lower amount of water for rinsing) in bitter likers after viewing neutral images. On the other hand, likers exhibited a further reduction in disgust to coffee after viewing stressor pictures, and also drank more water after tasting chocolate following the obesity pictures, compared with the dislikers. The expression of disgust increased in bitter likers, as well as the amount of water used to rinse the mouth, after tasting chocolate following pictures showing obesity compared with pictures showing food. These results show, for the first time, not only the implication of affective and incentive components in reversal of the predisposition to reject bitterness but also the motivational modulation of the expression of rejection of bitter tastes in humans.     

Lingonberry juice lowers blood pressure of spontaneously hypertensive rats (SHR)

Lingonberries (Vaccinium vitis-idaea) are rich in polyphenols, such as proanthocyanidins, anthocyanins, flavonols and flavanols. Polyphenol-rich foods affect vascular health. We previously described improved endothelium-dependent vascular function as well as anti-inflammatory and anti-atherothrombotic effects in spontaneously hypertensive rats (SHR) fed with lingonberry juice. In the present study, we investigated the effects of lingonberry juice dose on blood pressure, vascular function and vascular inflammation in SHR in an 8 weeks’ study. Diluted (1:5) cold-compressed lingonberry juice was given as drinking fluid ad libitum to 5 week old SHR for 8 weeks. Control group (SHR) and normotensive reference group (Wistar-Kyoto) received tap water. Systolic blood pressure (SBP) was monitored weekly. Function of mesenteric artery rings was assessed in standard organ-bath chambers after 8 weeks. Biochemical and clinical chemistry variables were measured from plasma and urine. Lingonberry juice lowered SBP of SHR (p = 0.007). Endothelium-dependent vascular relaxation was not improved. Lingonberry treatment slightly affected plasma inflammatory markers (reduction of NOx and sICAM-1) and clinical chemistry variables (decreased alkaline phosphatase and increased chloride and calcium levels). In conclusion, Lingonberry juice at small concentrations lowers blood pressure in a long-term treatment in SHR.     

Assessing the authenticity of absinthe using sensory evaluation and HPTLC analysis of the bitter principle absinthin

Absinthe is a spirit drink that owes its bitter taste to substances found in the wormwood plant (Artemisia absinthium L.). The prohibition against absinthe has recently been annulled, giving rise to numerous inferior products that lack the organoleptic characteristics of wormwood. The monoterpene thujone, which occurs in the essential oil fraction of wormwood, has previously been used as a marker substance to confirm the authenticity of absinthe. However, thujone possesses adverse toxicological properties; thus modern procedures have been developed to remove this substance from absinthe. In addition, thujone-free wormwood is also available from certain cultivation areas.This study is the first to use sensory evaluation of wormwood taste, louche effect, and bitterness in order to classify absinthes. This study also introduces a simple, fast, and sensitive procedure using high-performance thin-layer chromatography (HPTLC) to assess the levels of absinthin, a characteristic bitter substance found in wormwood. Results of this study demonstrate a strong correlation between the concentration of wormwood and the organoleptically determined bitterness value (R = 0.75).     

The effect of modifying the distribution of sucralose and quinine on bitterness suppression in model gels

This study investigated the effect of simultaneously manipulating the spatial distribution of a sweet masking agent and bitter tastant within gelatine–agar gels on bitterness suppression, using sucralose and quinine. Sixty subjects participated in a series of paired comparison tests comparing different gel designs containing both sucralose and quinine, against a homogeneous control gel of identical overall sucralose (0.3 mM) and quinine content (0.3 mM). Twenty subjects also determined the bitterness reduction achieved in the homogeneous control gel by the addition of 0.3 mM sucralose to 0.3 mM quinine. Separating quinine and sucralose into different portions of the gel had no influence on bitterness suppression. Inhomogeneously distributing the quinine and sucralose into the same parts of the gel reduced the effectiveness of bitterness suppression. Inhomogeneously distributing the sucralose, while maintaining a homogeneous distribution of quinine, had no influence on bitterness suppression. Although an inhomogeneous distribution of sucralose increased sweetness perception and the addition of sucralose (0.3 mM) was found to substantially reduce bitterness in the homogeneous control, bitterness suppression was not enhanced when distributing the masking agent (sucralose) inhomogeneously.     

Incidence,populations and diversity of fungi from raw materials,final products and air of processing environment of multigrain whole meal bread

This study aimed to assess the incidence, to quantify and to assess the diversity of fungi in a multigrain whole meal bread processing plant. Two hundred and eight one (n = 281) samples were analyzed, including raw materials (n = 120), air samples (n = 136) and multigrain breads (n = 25). Among the raw materials, the whole corn flour showed the highest counts of fungi (4.8 log CFU/g), followed by whole-wheat flour (3.1 log CFU/g). The counts of fungi in the air of processing environment were higher in post-baking steps (oven output, cooling, slicing, packaging) than in pre-baking steps (weighing and mixer) (p < 0.05). Species of fungi isolated from spoiled bread samples stored at 5, 20, 25 and 30, and 40 °C corresponded mostly to Penicillium paneum and Penicillium polonicum isolated from 20 and 24% of samples, respectively. These species were also isolated from raw materials (P. paneum and P. polonicum) and air collected at different processing sampling points (P. polonicum). The high counts of filamentous fungi in raw materials and air samples in processing steps such as cooling, slicing, and packaging, suggest that contamination that may occur in these steps can be critical for the shelf life of breads. The results of this study highlight that the prevention of contamination of breads by fungal spores is still a challenge for bakery industries and that other strategies such as control of germination and growth of spoilage fungi through the development of more stable formulations have to be developed.     

Comparison of partial and global projective mapping with consumers: A case study with satiating cheese pies

In the present work the performance of global projective mapping and partial projective mapping based on texture and flavor for sensory characterization of a novel food category (satiating food product) was compared. Eight different fresh-cheese pie formulations were designed to obtain different sensory (principally texture) characteristics which could affect expected satiating perception. Three groups of consumers evaluated the samples using one of the following methodologies: global projective mapping (G-PM) (n = 47), partial projective mapping based on flavor (F-PM) (n = 53), and partial projective mapping based on texture (T-PM) (n = 61). In addition, the expected satiating capacity of each cheese pie sample was scored on a nine-point scale. Results showed that the vocabulary used by consumers for describing the sensory characteristics of samples did not largely differ between global and partial projective mapping tasks. However, T-PM and F-PM tasks provided more detailed information than G-PM in each specific modality. Results suggested that when consumers performed the global projective mapping task they mainly took into account flavor characteristics for evaluating global similarities and differences among samples. In addition, hedonic attributes were more frequently mentioned in G-PM. Fresh cheese, sugar, corn starch and egg were the basic ingredients that conferred the fresh-cheese pies their typical, characteristic flavor and texture. The addition of whey or soy proteins, wheat bran or glucomannan increased expected satiating capacity which could be related to changes in texture (harder, more compact) leading to longer orosensory exposure. The addition of glucomannan caused the largest changes in the sensory characteristics of the cheese pies which in turn would be related to a decrease in perceived flavor intensity. Studying the interplay between formulations, sensory characteristics, expected satiating capacity and consumer liking could largely contribute to the development of this novel food category.     

The demographics of neophobia in a large commercial US sample

Neophobia was measured with two large (n = 1567 and n = 6843) commercial samples of US consumers on a 5-point Food Neophobia Scale. Results were compared with demographic data collected in other samples in the US and in other countries. Gender effects remain unclear; while neophobia appears to increase with age, while decreasing with increasing education and with increasing income. Results are explained by an increased exposure to foods with increasing income and education.     

The effect of brand names on flavor perception and consumption in restrained and unrestrained eaters

In an increasingly obesogenic food environment, making healthful food decisions can be difficult. Because consumers are often bombarded with excessive information about foods they often rely on simple heuristics to decide whether to purchase or consume a food. In the present study we tested females who were either restrained (n = 33) or unrestrained (n = 33) to determine whether their sensory perception and intake of a food would be affected by brand information. Participants were provided with in an ad libitum snack of cookies which was labeled with a brand typically associated with healthful snacks or a brand associated with unhealthful snacks. Results indicated that all participants rated the cookies with the healthful brand label as more satisfying and as having a better taste and flavor. Furthermore, restrained eaters consumed more of the healthful brand than the unhealthful brand, whereas unrestrained eaters’ consumption did not differ. Thus it appears that food-related beliefs do influence consumers’ intake, especially that of restrained eaters. Further research is warranted to investigate these beliefs in order to improve recommendations for healthful eating in a society facing an increased prevalence of overeating and obesity.     

Using a change-point model to describe temporal bitter relationships among hop-derived compounds

The bitterness of four hop-derived compounds was measured over a range of concentrations using a time–intensity protocol to determine temporal bitterness relationships. Bitter attributes were compared among compounds by applying a three parameter, change-point model to all concentration-dependent attributes whereby α represented the bitter parameter’s magnitude at very low compound concentrations up to a change-point concentration, θ, and β represented the log-linear concentration dependency of the bitter parameter above the change-point concentration, θ. Panelist reliability was determined by evaluating how well their data fit the model parameters as determined via a t-statistic. Analysis of variance of the concentration-dependent parameters, maximum intensity, duration, area-under-curve, and, decreasing area, identified differences among compounds. In the case of panelist × compound interactions, within-panelist analysis of change-point parameters yielded panel-wise relationships not initially detected.     

Short-term appetite-reducing effects of a low-fat dairy product enriched with protein and fibre

The objectives of this work were to investigate short-term appetite-reducing effects of an innovative low-fat yogurt enriched with protein (8 g/serving) and fibre (2.6–2.9 g/serving). Two studies were conducted using randomised cross-over designs. Healthy women consumed a mid-morning snack consisting of either the test or the control yogurt product (Study 1, n = 24: iso-energetic, not iso-weight conditions; Study 2, n = 121: iso-weight, not iso-energetic conditions) under laboratory conditions. Subjective appetite ratings (of hunger, fullness, desire to eat and prospective consumption) were recorded throughout the morning; sensory and hedonic ratings were also collected. In Study 2, two hours after consumption of the dairy snack, subsequent food intake at lunch was also measured. The test product reduced subjective appetite compared to the control (all ratings, P < 0.05). Energy intake at lunch was reduced by 274 kJ after the test compared to the control (P < 0.001). These two studies demonstrated that a low-fat dairy product enriched with protein and fibre can significantly reduce short-term appetite.     

School meal acceptance depends on the dish,student, and context

Students (n = 127) from grades 3, 6, and 8 (8–15-year-old) evaluated 13 school meals with special attention to main dishes. Hedonic ratings (1 = really bad, 7 = really good) of 1109 meals, perceived hunger prior to eating, and aspects of the eating context were rated. Attitudes to school meals and food neophobia were measured. Considerable differences were observed in responses to main dishes, soups being better accepted than casseroles or dishes served with starches. A semi-trained laboratory panel (n = 17) characterized the best liked main dishes as being recognizable by appearance, odor and flavor, and bright and colorful, while the least liked dishes were described as having fatty mouth feel and cheesy odor and flavor. Hedonic ratings of main dishes were highly correlated with overall meal ratings. The 3rd graders rated the main dishes higher than 6th and 8th graders, who perceived them as too low in spiciness and not hot enough when served. Typically, 3rd grade boys rated the meals most positively and 6th grade boys most negatively. Attitudes to school meals were more positive in 3rd graders than in higher-grade students. In regression analysis explaining 29.7% of variation, hedonic ratings of the meals were positively predicted by attitudes to school food, perceived hunger, and appropriate queuing in the canteen, and negatively predicted by food neophobia and being a 6th or 8th grader. In conclusion, sensory characteristics of main dishes greatly affect the popularity of school meals; and means to impact the negative attitude to school food in teenage would be of great use.     

Effects of an evoked refreshing consumption context on hedonic responses to apple juice measured using best–worst scaling and the 9-pt hedonic category scale

Awareness of the need to consider a product’s consumption context when measuring consumer hedonic response of a product is increasing among consumer sensory researchers. This study investigated the effects of evoking a consumption context using a written scenario on hedonic response measured using best–worst scaling and the 9-pt hedonic category scale. Hedonic responses for four apple juices with relatively large sensory differences were compared when measured in the evoked context ‘when having something refreshing to drink’ using best–worst hedonic scaling (n = 65) and the 9-pt hedonic scale (n = 48). Best–worst scaling discriminated between the four apple juices when a refreshing context was evoked (p < 0.01), while the juices were equally liked using the 9-point scale (p = 0.41) when the same context was evoked. Consumers perceived best–worst scaling to be more difficult than the 9-pt scale, however there was no difference between the two methods for consumers perceived accuracy of their liking information. The present study highlights that the effect of an evoked context on hedonic response may not be universal for hedonic methods. Further research is needed to understand the effect of evoking context on the liking of products, and to determine whether this measure reflects product liking in an actual consumption context.