Bitter Foods Research Articles

Altering salivary protein profile can decrease aversive oromotor responding to quinine in rats

Bitter taste is often associated with toxins, but accepting some bitter foods, such as green vegetables, can be an important part of maintaining a healthy diet. It has previously been shown that animals exposed to quinine upregulate a set of salivary proteins (SPs), and those with upregulated SPs have increased rates of feeding on a quinine diet as well as increased brief-access licking to and higher detection thresholds for quinine. These studies suggest that SPs alter orosensory feedback; however, they rely on SPs upregulated by diet exposure and cannot control for the role of learning. Here, we use taste reactivity to determine if SPs can alter bitter taste in animals with no previous bitter diet experience. First, saliva with proteins stimulated by injections of isoproterenol and pilocarpine was collected from anesthetized rats; this “donor saliva” was analyzed for protein concentration and profile. Bitter-naïve rats were implanted with oral catheters and infused with taste stimuli dissolved in saliva that contained all of the SPs from the donors, saliva that was filtered of SPs, water, or artificial saliva. Their orofacial movements were recorded and quantified. We found that presence of quinine increased movements associated with aversive stimuli, but adding SPs to the infusion was sufficient to reduce aversive oromotor responding to quinine. The effect was dependent on the total protein concentration of the saliva, as protein concentration increased aversive responses decreased. Additionally, infusions of whole saliva altered aversive responding to quinine, but not other stimuli (citric acid, NaCl, sucrose). Our work suggests that effect of these SPs is specific and the presence of SPs is sufficient to decrease aversive orosensory feedback to bitter stimuli.

Personality traits and bitterness perception influence the liking and intake of pale ale style beers

Bitterness is classically considered undesirable in foods and beverages. Yet, widespread commercial success of beers (like Bitters in the UK or IPAs in the US) indicate bitterness is desirable for some consumers. Here, we tested whether personality traits influence beer liking and intake. Under laboratory conditions, beer consumers (n = 109) rated liking and intensity of 2 pale ales and a lager, and intensity of two bitter solutions (quinine, Tetralone®). Participants also completed intake and personality questionnaires (Sensation Seeking, Sensitivity to Punishment and Reward, and Food Involvement). A liking ratio for each beer was calculated from each participant’s liking for that specific beer and their total liking for all beers. Participants were classified as weekly, monthly, or yearly pale ale consumers using intake data. Using intensity ratings, personality measures, and other parameters, hierarchical linear regression was used to predict liking ratios, and logistic regression was used to predict beer intake frequency. A significant interaction between Sensation Seeking and quinine bitterness (p = 0.03) was found for the liking ratio of a pale ale. The interaction revealed liking of the pale ale increased with Sensation Seeking but only if quinine bitterness was also high. Intake models showed increased odds of frequent pale ale intake with greater quinine bitterness and lower liking for lager beer. These data suggest liking and intake of pale ales is positively related to Sensation Seeking and bitter taste perception. Contrary to findings in other bitter foods and beverages, the high bitterness found in pale ales may be desirable for some consumers.

Exploring individual variation in associative learning abilities through an operant conditioning task in wild baboons.

Cognitive abilities underpin many of the behavioural decisions of animals. However, we still have very little understanding of how and why cognitive abilities vary between individuals of the same species in wild populations. In this study, we assessed the associative learning abilities of wild chacma baboons (Papio ursinus) across two troops in Namibia with a simple operant conditioning task. We evaluated the ability of individuals to correctly associate a particular colour of corn kernels with a distasteful flavour through repeated presentations of two small piles of corn dyed different colours, one of which had been treated with a non-toxic bitter substance. We also assessed whether individual variation in learning ability was associated with particular phenotypic traits (sex, social rank and neophilia) and states (age and prior vigilance). We found no evidence of learning the association either within each trial or across trials, nor any variation based on individuals' phenotypes. This appeared to be due to a high tolerance for bitter foods leading to similar acceptance of both palatable and unpalatable kernels. Earlier avoidance of the bitter kernels during pilot trials suggests this higher tolerance may have been largely driven by a drought during the experiments. Overall, our findings highlight the potential influence of current environmental challenges associated with conducting cognitive tests of animals in the wild.

Polymorphism of TAS2R3, TAS2R5, TAS2R19, and TAS2R50 genes and bitter food intake frequency inelderly woman.

Taste sensitivity is one of the most important biological determinants of food choice. Polymorphisms within the bitter taste receptor genes TAS2R3 (rs765007), TAS2R5 (rs2234012), TAS2R19 (rs10772420), and TAS2R50 (rs1376251) may affect bitter taste sensitivity and thus food choices and thereby metabolic biomarkers in blood. The aim of this study was to investigate associations between selected TAS2Rs  single nucleotide polymorphisms (SNPs) and the choice of the most popular bitter food items in    a Polish population, BMI and blood biomarkers in elderly women. The study group included 116 Polish women over 60 years of age. Intake of Brassica vegetables, grapefruit and coffee was assessed using a food frequency questionnaire. Biochemical parameters were measured using the spectrophotometric method. Genotyping was performed using the high resolution melting method. We show an association between SNPs of the TAS2R3 gene and the frequency of Brassica vegetable intake, between SNPs of the TAS2R5 gene and the frequency of grapefruit intake, and between the simultaneous effects of polymorphisms within TAS2R3 and TAS2R5 and the frequency of eating Brassica vegetables in general. We found no association between the genetic polymorphisms of TAS2R19 or TAS2R50 that were examined and the frequency of bitter-tasting food intake. Moreover, the SNPs of the selected TAS2Rs genes may be associated with the lipid profile, serum level of glucose and CRP, depending on the frequency of consumption of particular bitter-tasting items. The genetic polymorphisms analyzed in the study seem not to contribute significantly to variability in bitter-tasting food intake in elderly women, although they may influence metabolic biomarkers dependent on the intake of particular bitter-tasting food items.

Polymorphism of TAS2R3, TAS2R5, TAS2R19, and TAS2R50 genes and bitter food intake frequency inelderly woman [pdf

Polymorphism of TAS2R3, TAS2R5, TAS2R19, and TAS2R50 genes and bitter food intake frequency inelderly woman [pdf

Sensitive period for the acceptance of unpalatable flavors in the presence of a preexposed odor in infant rats.

It has been shown that exposure to familiar odors facilitate the acceptance of bitter flavors in preweanling rats, yet it unknown how long this phenomenon persists. This study assessed, in 9- or 15-day-old Wistar rats, the influence of a familiar scent (i.e., lemon) on the intake of and behavioral responsiveness (i.e., mouthing, paw lick, chin rub, head shake, among other taste reactivity responses) elicited by a 0.1% quinine solution. The results showed heightened quinine intake in 9-day-old rats that had been preexposed to the odor, when compared to non-preexposed controls. This result was replicated in Experiment 2, which also documented no alterations in behavioral responsiveness toward quinine in the 9-day-old rats, as a function of the pre-exposure. More importantly, 15-day-old rats exhibited no alterations in intake or behavioral responsiveness toward quinine as a function of odor pre-exposure. These results suggest that the effects of odor pre-exposure upon acceptance of bitter tastes may occur within a sensitive period for the acceptance of bitter food.

Traditional methods used by mothers living in different regions of Turkey for increasıng breast milk supply and weaning

<b>Introduction:</b> It is a known fact that traditional practices mothers use in increasing breast milk supply and weaning differ in different parts of countries and even among communities sharing the same city. This study was conducted to find out the use of herbal tea and some foods to increase breast milk, the traditional methods used for weaning and the factors influencing these. <br><b>Materials and methods:</b> This study is descriptive and cross-sectional. Three cities in Turkey with different levels of development in terms of geographical and socio economic regions were chosen. The data of the study were collected through a questionnaire form developed by the researchers. <br><b>Results:</b> It was found that the mothers who received breast milk increasing training the most were in eastern region, while mothers in western region fed their babies with formula since they thought their milk was not enough and this result was found to be statistically significant (p<0.05). In our study, it was found that 42.1% of the mothers resorted to some plants and foods to increase breast milk. When the mothers were asked about how they weaned their babies, it was found that 38.2% pasted things like hair and wool or put tomato paste on the breast, 26.9% applied bitter food on the nipple while 27.7% stated that the babies stopped breastfeeding spontaneously. <br><b>Conclusion:</b> It was found that mothers resorted to traditional methods to increase breast milk and to wean and that there were regional differences.

The determinants of chemoreception as evidenced by gradient boosting machines in broad molecular fingerprint spaces

The ability to identify and reject bitter molecules may determine evolutionary fitness. These molecules might be in potentially toxic or contaminated food. Surprisingly, the ability to identify but tolerate or even enjoy bitter foods and medicines may be beneficial. For example, the tolerance of bitterness as a spice or as a medicine may lead to better nutritional, immunological and health outcomes. More recently the ability of intensely bitter compounds to induce innate immune responses to counter infection has inspired the screening of new drugs and the repurposing of safe, known drugs to new uses. These avenues of study may also help to address long-standing questions regarding unexpected side-effects and placebo/nocebo effects. Therefore, to distinguish all these effects ranging from desire to aversion, there is a need to quantitatively determine the concentration thresholds and to position these bitter substances on a unified taste threshold spectrum. Such an understanding may help elucidate the concentration-based molecular drivers for the chemoreceptive response to bitter substances. This article reports the development of a gradient boosting machine (GBM) that enables a direct interrogation of molecular structure with no intermediary chemical properties. Using molecularly engineered simulations, it is shown that potassium acesulfame has a hidden bitterness motif that is centered on the chemoreceptive spectrum uniting bitterness and sweetness molecular motifs. The resultant shifted perception from a touchstone bitterness sensation to a bitter after-taste is attributable to this cached molecular motif.

Preference for and sensitivity to flavanol mean degree of polymerization in model wines is correlated with body composition

Bitterness and astringency (dryness) are characteristic sensory attributes of flavanol-rich foods. The degree of polymerization (DP) of flavanols influences their bitter and astringent sensations. Smaller DP compounds can enter the papillae on the tongue, eliciting a bitter response. Larger DP compounds are sterically inhibited from entering papillae and instead interact with oral proteins, cause precipitation, and elicit astringent sensations. Previous research has indicated that bitterness preference is related to health status, density of fungiform papillae on the tongue, and sensitivity to bitter compounds such as 6-n-propyl-thiouracil (PROP). The purpose of this study was to examine trends in liking, bitterness intensity, and astringency intensity of wine-like products with flavanols of different DP using a consumer sensory panel. Participants (n = 102) were segmented by phenotypes: body fat percentage (BF%), body mass index (BMI), PROP sensitivity, and stated bitter food preference. Differences in wine liking, perceived bitterness intensity, and astringency intensity were observed between three model wine samples of varying flavanol mean degrees of polymerization (mDP, i.e. the average size (polymer length) of flavanol compounds in a mixture). Specifically, with increased mDP, overall liking and bitterness liking decreased, with concurrent increased perception of bitterness and astringency intensity. Greater differences between phenotypes were observed when participants were segmented by BF% and BMI classification, than when segmented by PROP sensitivity classification. Reduced ability to detect differences in bitterness and astringency were noted in participants of higher weight status. Overall, these data suggest that weight status in adults is a greater predictor of liking of flavanol-rich foods than bitterness sensitivity (as determined by PROP classification), and that reduced perception of bitterness and astringency associated with weight gain may impact selection and preference for these foods.

Preference for and Sensitivity to Flavanol Mean Degree of Polymerization in Model Wines Is Correlated with Body Composition (P06-100-19)

ObjectivesIt is known that the degree of polymerization (DP) of flavanol compounds influences the perceived bitter and astringent sensations of flavanol-rich foods. Previous research has indicated that preference for bitterness and astringency is related to health status (i.e., obesity) and sensitivity to bitter compounds such as 6-n-propyl-thiouracil (PROP). The objective of this study was to examine trends in liking, bitterness intensity, and astringency intensity of wine-like products with distinct flavanols of different DP in a consumer sensory panel when consumers were differentiated by phenotype. MethodsRecruited panelists (n = 102) were segmented into different phenotypes based on body fat percentage (BF%), body mass index, PROP sensitivity, and stated preference for bitter foods. Differences in overall product liking, perceived bitterness intensity, and astringency intensity were observed between the three wine samples formulated to contain varying flavanol mDP. ResultsConsidering the panelists altogether without segmentation, overall liking and bitterness liking decreased with increasing flavanol mDP, with concurrent increased perception of bitterness and astringency intensity. When looking at specific phenotypes, subjects of higher BMI and BF% showed significantly reduced ability to detect differences in bitterness and astringency intensity. Interestingly and unexpectedly, PROP sensitivity and self-reported bitterness preference did not significantly correlate with liking and intensity trends based on flavanol mDP. ConclusionsOverall, these data suggest that BF% and BMI are greater predictors of liking and sensitivity to flavanol-rich foods compared bitterness sensitivity and self-reported bitterness liking. Reduced perception of bitterness and astringency associated with weight gain may impact selection and preference for these foods. Funding SourcesFunding for this work was provided in part by the Virginia Tech Translational Obesity Research Graduate Interdisciplinary Research Program and the Virginia Tech Agricultural Experiment Station, and the Hatch Program, USDA-NIFA.

Consumers' Perceptions and Preferences for Bitterness in Vegetable Foods: The Case of Extra-Virgin Olive Oil and Brassicaceae-A Narrative Review.

The presence of some healthy phytochemicals in food can be paired with high bitterness, and consumers have a widespread avoidance toward bitter-tasting food. This causes a gap between preferences and healthy needs of consumers. Therefore, this review collected insights from literature belonging to different discipline domains in order to have a broad view of the current state-of-the-art about biochemical aspects and consumers’ perceptions and preferences toward foods with an enhanced bitter taste. In detail, we focused on two core products of the Mediterranean diet: Extra-virgin olive oil (EVOO) and Brassicaceae, both characterized by specific phytochemicals having strong healthy properties and bitter-pungent taste. Results suggested that, although bitter taste is a general driver of dislike, some exceptions can be represented by: niches of consumers (e.g., innovators and organic buyers), foods consumed with specific purposes (e.g., coffee, chocolate, and alcoholic beverages). The level of bitterness perceived by the consumers can be modulated through exposure, information on benefits, and elements within the environment (e.g., music). Thus, these insights can be used to develop specific campaigns aimed at promoting bitter (healthy) food, considering also the key role that could be played by food pairings.

Association Between Pretreatment Dietary Preference and Weight Loss after Radiation Therapy in Head and Neck Cancer Patients: A Pilot Study

Weight loss is common in cancer patients underwent radiation therapy. However, the impact of pretreatment behavior on postradiation nutritional status was unknown. This prospective observational study was conducted in 31 Thai head and neck cancer patients to investigate the association between pretreatment dietary preference and weight change after radiotherapy. Pretreatment preferences on sweet, salty, sour, bitter, umami, spicy, and fatty food were evaluated using a validated questionnaire, TASTE26. Body weights were monitored at baseline, 1,000–2,000, 2,800–3,400, 4,000–4,400, and 5,000–7,000 cGy of radiations and 2 month-follow up after radiotherapy. The energy intakes were analyzed by using 3 day-dietary record and INMUCAL software. Spicy food preference was the only factor found positively correlated with weight loss after radiation (r = 0.64, P = 0.007). Consistently, strong spicy lovers had more pronounced reduction of energy intake and body weight, and higher needs of tube feeding than those of mild or moderate lovers (P < 0.05). This study suggested that stronger preference on spicy food may be associated with less energy intake and more severe weight loss after radiation therapy. A large-scale study is warranted to confirm such findings. Then, preradiation screening for spicy preference may be useful to predict weight loss during radiation therapy.

Are (All) Consumers Averse to Bitter Taste?

The current study combined hedonic liking with non-hypothetical experimental auctions to measure consumer preferences for bitter tasting food and identify individual socio-demographic and psychographic characteristics that influence bitter aversion. Furthermore, the research analyzed whether consumer preferences for bitter food were influenced by sensory and health-related information. Findings reveal that respondents (N = 205) are not averse to bitter taste; while, socio-demographic traits influence bitter acceptance, as higher education level and gender (female) positively affect preferences, together with specific individual characteristics as high compensatory health beliefs. Moreover, results prove that participants positively respond to health-related information, whereas information on bitterness-taste generates lower preferences.

Hating vegetables, loving cold coffee

Bitter gets better The end of January is traditionally when people abandon their New Year’s resolutions. But Newscripts is hanging in there, staring down a plate of—what is that, kale?—in pursuit of that holy grail of healthfulness, the plant-based diet. One good reason to carry on, cruciferously, is that humans can overcome their instinct to turn away from bitter foods over time. In short, it gets better. Routine exposure can even foment a love for bitter flavors such as dark chocolate, hoppy beer, and even leafy greens. Researchers want to know how we acquire a taste for bitter food compounds like healthy polyphenols in plants. One secret may be in our saliva. Studies by Cordelia Running, a professor of nutrition and food science at Purdue University, suggest proteins in our saliva change over time in ways that may alter how those foods taste. Running conducts human taste experiments at her

AYURVED &amp; MODERN VIEW IN CHICKEN POX (MASURIKA/LAGHU MASURIKA): A REVIEW

 BACKGROUND: According to modern literature Chicken pox is an aerosol disease caused by virus called ‘Varicella zoster’. It is highly contagious disease; it progressively spreads from ill ones to healthy, like cold &amp; flu. Age group under 10 years is mostly affected by this disease &amp; in adults it occurs rarely. For prevention Chicken Pox vaccine is must to be given two times in the age between 10 months to 15 months &amp; in 4 years to 6 years. But after vaccinating against Chicken Pox some of them also suffer from this disease. In Ayurveda according to Madhav Nidana chicken pox (Masurika/LaghuMasurika) is caused by Grahadosha as well as by vitiation of Tridoshas i.e. Vata, Pitta, Kapha &amp; also by consuming excessive sour, salty, bitter food items &amp; Virudhaahara Sevan (eg. Milk with fish etc.). Ayurveda also gives preventive &amp; curative measures for this disease.  OBJECTIVES: To study review literature of Chicken Pox (Masurika/LaghuMasurika) through Ayurved &amp; Modern text.  METHODS: The ancient knowledge of Chicken Pox (Masurika/Laghu Masurika) through Samhitas, modern literature and various journal, internet is gathered and data is collected for this study.  RESULTS AND CONCLUSION: After the study of literature, it is clear that Chicken Pox (Masurika/LaghuMasurika) is prevented &amp; treated by Ayurveda &amp; Modern science.

Altering salivary protein profile can increase acceptance of a novel bitter diet

Bitter taste is often associated with toxins, but accepting some bitter foods, such as green vegetables, can be an important part of maintaining a healthy diet. In rats and humans, repeated exposure to a bitter stimulus increases acceptance. Repeated exposure allows an individual the opportunity to learn about the food's orosensory and postingestive effects. It also alters the salivary protein (SP) profile, which in turn alters taste signaling. We have hypothesized that altering the salivary proteome plays a role in the increased acceptance after repeated exposure. Here we test this and attempt to disentangle the contribution of learning during dietary exposure from the contribution of SPs in increased acceptance of bitter diet. Dietary exposure to quinine or tannic acid and injection of isoproterenol (IPR) result in similar salivary protein profiles. Here we used either the bitter stimulus tannic acid or IPR injection to upregulate a subset of SPs before exposing animals to a novel diet containing quinine (0.375%). Control animals received either a control diet before being exposed to quinine, or a diet containing sucrose octaacetate, a compound that the animals avoid but does not alter SP profiles. The treatments that alter SP expression increased rate of feeding on the quinine diet compared to the control treatments. Additionally, tannic acid exposure altered intake and meal size of the quinine diet. These data suggest that SPs, not just learning about bitter food, increase acceptance of the bitter diet.

A Sweet Voice: The Influence of Cross-Modal Correspondences Between Taste and Vocal Pitch on Advertising Effectiveness.

We have seen a rapid growth of interest in cross-modal correspondences between sound and taste over recent years. People consistently associate higher-pitched sounds with sweet/sour foods, while lower-pitched sounds tend to be associated with bitter foods. The human voice is key in broadcast advertising, and the role of voice in communication generally is partly characterized by acoustic parameters of pitch. However, it remains unknown whether voice pitch and taste interactively influence consumer behavior. Since consumers prefer congruent sensory information, it is plausible that voice pitch and taste interactively influence consumers' responses to advertising stimuli. Based on the cross-modal correspondence phenomenon, this study aimed to elucidate the role played by voice pitch-taste correspondences in advertising effectiveness. Participants listened to voiceover advertisements (at a higher or lower pitch than the original narrator's voice) for three food products with distinct tastes (sweet, sour, and bitter) and rated their buying intention (an indicator of advertising effectiveness). The results show that the participants were likely to exhibit greater buying intention toward both sweet and sour food when they listened to higher-pitched (vs lower-pitched) voiceover advertisements. The influence of a higher pitch on sweet and sour food preferences was observed in only two of the three studies: studies 1 and 2 for sour food, and studies 2 and 3 for sweet food. These findings emphasize the role that voice pitch-taste correspondence plays in preference formation, and advance the applicability of cross-modal correspondences to business.

Innate and acquired tolerance to bitter stimuli in mice.

Tolerance to bitter foods and its potentiation by repetitive exposure are commonly experienced and potentially underlie the consumption of bitter foods, but it remains unknown whether permissive and adaptive responses are general phenomena for bitter-tasting substances or specific to certain substances, and they have not been rigorously studied in mice. Here, we investigated the effects of prolonged exposure to a bitter compound on both recognition and rejection behaviors to the same compound in mice. Paired measurements of rejection (RjT) and apparent recognition (aRcT) thresholds were conducted using brief-access two-bottle choice tests before and after taste aversion conditioning, respectively. First, RjT was much higher than aRcT for the bitter amino acids L-tryptophan and L-isoleucine, which mice taste daily in their food, indicating strong acceptance of those familiar stimuli within the concentration range between RjT and aRcT. Next, we tested five other structurally dissimilar bitter compounds, to which mice were naive at the beginning of experiments: denatonium benzoate, quinine-HCl, caffeine, salicin, and epigallocatechin gallate. RjT was moderately higher than aRcT for all the compounds tested, indicating the presence of innate acceptance to these various, unfamiliar bitter stimuli in mice. Lastly, a 3-week forced exposure increased RjT for all the bitter compounds except salicin, demonstrating that mice acquire tolerance to a broad array of bitter compounds after long-term exposure to them. Although the underlying mechanisms remain to be determined, our studies provide behavioral evidence of innate and acquired tolerance to various bitter stimuli in mice, suggesting its generality among bitterants.

Sensory characteristics of human milk: Association between mothers' diet and milk for bitter taste

It is unknown how consumption of bitter foods and beverages in the maternal diet influences sensory properties of fresh human milk. The aims of this study were (1) to determine the sensory characteristics of fresh human fore and hind milk, (2) to establish relationships between sensory properties and composition of fresh human milk, and (3) to assess the relationship between bitterness of the maternal diet and human milk. Twenty-two lactating mothers generated sensory terms to describe perception of their milk and received training on sensory attribute intensity rating. Mothers kept a 24-h food diary followed by a sensory self-assessment of their fore and hind milks. The odor of human fresh milk was described as neutral, creamy, and sweet, taste as sweet and bitter, and mouthfeel as thin, watery, smooth, and fatty. Sweetness was equivalent to 1.53 g of sucrose/100 mL and was not significantly different between fore and hind milk. Fore milk was significantly less creamy, less fatty, thinner, more watery, and lower in vanilla flavor intensity than hind milk. Carbohydrate content of human milk was positively correlated with sweetness and glutamic acid content with umami. The bitterness of the diet consumed 24 h before lactation was moderately positively correlated with bitterness of fore milk, but not hind milk. We conclude that the consumption of bitter foods may influence the bitterness of human fore milk, which may be another way for breastfed children to learn to accept bitter vegetables and, hence, develop healthier food preferences.

Lifting, tasting, and carrying: The interaction of magnitude and valence effects in time perception

Magnitude effects (e.g., heavier or faster is longer) and valence effects (e.g., negative > positive) are widely observed in time perception studies, but not well understood. In four experiments, we explored how different action contexts (e.g., tasting, lifting) affected magnitude and valence effects. In two experiments a valence effect occurred: Tasting a sweet food (watermelon) led to temporal underestimations relative to a neutral stimulus, while sour and bitter foods led to overestimations. However, when the same foods were presented in a lifting context a magnitude effect occurred: Reproduced times for the heavier food (watermelon) were overestimated relative to the lighter foods. In a fourth experiment magnitude and valence interacted: Imagining tasting increasing amounts of lemon or carrying increasing loads of lemon, both negative, yielded magnitude effects; however, imagining carrying lemons to feed malnourished people, which was positive, did not. Results present challenges for several common theoretical approaches (e.g., arousal, attention, common magnitude theory) but provide support for affordance theory and perceptual salience theory. Timing depends on action relevance and is jointly shaped by valence and magnitude.