Application of electroencephalogram (EEG) in the study of the influence of different contents of alcohol and Baijiu on brain perception.

Alcoholic beverages flavour is complex and unique with different alcohol content, and the application of flavour perception could improve the objectivity of flavour evaluation. This study utilized electroencephalogram (EEG) to assess brain reactions to alcohol percentages (5 %-53 %) and Baijiu's complex flavours. The findings demonstrate the brain's proficiency in discerning between alcohol concentrations, evidenced by increasing physiological signal strength in tandem with alcohol content. When contrasted with alcohol solutions of equivalent concentrations, Baijiu prompts a more significant activation of brain signals, underscoring EEG's capability to detect subtleties due to flavour complexity. Additionally, the study reveals notable correlations, with δ and α wave intensities escalating in response to alcohol stimulation, coupled with substantial activation in the frontal, parietal, and right temporal regions. These insights verify the efficacy of EEG in charting the brain's engagement with alcoholic flavours, setting the stage for more detailed exploration into the neural encoding of these sensory experiences.

Gastrodin attenuates high fructose-induced sweet taste preference decrease by inhibiting hippocampal neural stem cell ferroptosis.

INTRODUCTION: High fructose intake has been implicated as a risk factor for behavioral disorders, potentially through cell ferroptosis induction in the central nervous system. Neural stem cells (NSCs) are crucial for maintaining hippocampal neurogenesis to resist behavioral alterations. Gastrodin, derived from the traditional Chinese herb Gastrodia elata, has neuroprotective effect. OBJECTIVES: This study aimed to elucidate the underlying mechanism by which high fructose induces sweet taste preference and assesses the impact of gastrodin on hippocampal NSC ferroptosis. METHODS: Mice and cultured NSCs were treated with high fructose and/or gastrodin, respectively. NSC ferroptosis was evaluated by assay of lipid peroxidation and DNA double-strand breaks. Transcriptome sequencing (RNA-seq), Western blotting, and chromatin immunoprecipitation (ChIP) were employed to explore the potential mechanism underlying high fructose-induced NSC ferroptosis and the modulation of gastrodin. Simultaneously, specific gene expression was regulated by lentivirus injection into the hippocampus of mice. RESULTS: Our data showed that gastrodin mitigated sweet taste preference decline and hippocampal NSC ferroptosis in high fructose-fed mice, being consistent with reduction of reactive oxygen species (ROS) and iron accumulation in hippocampal NSC mitochondria. Mechanistically, we identified CDGSH iron-sulfur domain 1 (CISD1) as a mediator of NSC ferroptosis, with its expression being augmented by high fructose. Overexpression of Zic family member 2 (ZIC2) increased the transcription of Cisd1 gene. Additionally, overexpression of Zic2 with lentiviral vectors in hippocampus showed the decreased sweet taste preference in mice, consistently up-regulated CISD1 protein expression and reduced hippocampal NSC number. Gastrodin downregulated ZIC2 expression to inhibit CISD1 transcription in its attenuation of high fructose-induced NSC ferroptosis and sweet taste preference decrease. CONCLUSION: Collectively, high fructose can drive hippocampal NSC ferroptosis by upregulating ZIC2 and CISD1 expression, thereby contributing to the decline in sweet taste preference. Gastrodin emerges as a promising agent for mitigating NSC ferroptosis and improving sweet taste preference.

Application of multiple dynamic sensory techniques to N-lauroyl amino acids: Exposing the relationship between taste-enhancing properties and chemical structure.

This study investigated the taste enhancing effects of N-lauroyl amino acids, including N-lauroyl-phenylalanine, N-lauroyl-tryptophan and N-lauroyl-tyrosine. Sensory results obtained through TDS, TCATA, and TI assessments indicated that all N-Lau-AAs significantly increased the umami intensity and duration of solutions such as simulated chicken broth. Moreover, these compounds masked bitter taste, with LTR showing the most pronounced reduction of bitterness. LP had the effect of enhancing saltiness, whereas LTR and LTY diminished saltiness. Structural analysis revealed a correlation between the chemical structure of N-Lau-AAs and their sensory properties. The presence of carbon­carbon double bond (CC) was positively correlated with umami intensity and negatively correlated with bitter and salty parameters. Phenolic hydroxyl groups (OH) were negatively correlated with umami intensity and positively correlated with a decrease in bitterness intensity and duration. Overall, this study provides valuable insights into the taste enhancement potential of N-Lau-AAs as taste enhancers in the food industry.

From menus to misbeliefs: Absolute frequencies of healthy and tasty dishes predict the unhealthy = tasty belief in restaurants.

We examine whether the prevalence of healthy and tasty food options in restaurant menus leads to the formation of beliefs about the relationship between healthiness and taste that deviate from the correlation of healthiness and taste ratings. Participants (N = 195) rated the healthiness and taste of twelve dishes from two different restaurant types (American and vegetarian restaurants), estimated the frequencies of healthy and tasty options, and reported their health-taste beliefs. Results show that ratings of perceived healthiness and expected taste are uncorrelated in both restaurant types, but participants formed the misbelief that unhealthy dishes taste better than healthy dishes to a greater extent in American than in vegetarian restaurants. Regression analyses revealed that the absolute frequencies of food options were significantly related to participants' health-taste beliefs while controlling for the correlation between healthiness and taste ratings in both restaurant types. Participants were more likely to believe that healthy food tastes better than unhealthy food when they perceived that healthy and tasty food were both frequent (or infrequent) in the respective restaurant type. Our results provide evidence that relying on absolute frequencies, rather than covariation, to infer the relationship between healthiness and taste may lead to misbeliefs that do not reflect the health-taste correlation of individual food items.

Miracle Fruit, a Potential Taste-modifier to Improve Food Preferences: A Review.

PURPOSE OF REVIEW: The miracle fruit contains the glycoprotein miraculin which can modify the taste perception of food and beverages at low pH conditions, altering the consumers' food preferences. This review aims to critically evaluate all available evidence on miracle fruit/ miraculin and taste modification and its potential role in improving food preferences. RECENT FINDINGS: Miracle fruit suppresses sourness and induces sweetness in acidic food/ beverages. At low pH conditions, miracle fruit enhances the sweet taste and decreases the perceived intensities of salty and bitter tastes in solutions. However, the role of miracle fruit in sweet, salty, and bitter food is not adequately studied. The above effects alter the food-liking scores in individual foods and mixed diets. Miracle fruit is a pH-dependent taste modifier with the potential to be used in food applications to improve consumer food preferences. Future research on the changes in food preferences with the optimum miraculin dose, food type, and intrapersonal variations in taste sensitivity is warranted.

Different taste map for amiloride sensitivity, response frequency, and threshold to NaCl in the rostral nucleus of the solitary tract in rats.

Studies on taste bud cells and brain stem relay nuclei suggest that alternative pathways convey information regarding different taste qualities. Building on the hypothesis that amiloride (epithelial Na channel antagonist)-sensitive neurons respond to palatable salt (low-concentration) and amiloride-insensitive neurons respond to aversive salt (high-concentration), we investigated the histological distribution of taste-sensitive neurons in the rostral nucleus of the solitary tract in rats and their NaCl and amiloride sensitivities. We recorded neuronal activity in extracellular single units using multi-barrel glass micropipettes and reconstructed their locations on the rostrocaudal and mediolateral axes. Seventy-three taste-sensitive neurons were categorized into the best-taste category. The amiloride sensitivities of the 31 neurons were examined for 0.1, 0.2, 0.4, and 0.8 M NaCl. The neuronal distribution of amiloride-sensitive neurons was located in the lateral region, while amiloride-insensitive neurons were located in the medial region. The amiloride-sensitive neurons responded to low salt concentrations, signaling the NaCl levels required by body fluids. Amiloride-insensitive neurons were silent at low salt concentrations but may function as warning signals for high salt concentrations. Low-threshold and/or high-response neurons were located in the rostrolateral region. In contrast, high-threshold and/or low-response neurons were located in the caudal-medial region.

Use of Buzz Buttons to Illustrate Taste Perception Principles in a Sensation and Perception Laboratory Exercise.

The buzz button is an edible flower that induces a tingling, electric sensation in the mouth and alters the perception of different flavors. The buzz button's taste-altering effect is thought to be caused by the bioactive compound spilanthol. The present article details a laboratory exercise that explores taste perception principles using the buzz button in an undergraduate Sensation and Perception course. A detailed step-by-step guide for the laboratory exercise is included along with analyzed student results. Students first sampled various food items that spanned the different taste sensations (i.e., salty, sweet, sour and bitter) and then rated their perceived taste intensity on a scale from one (not intense) to ten (very intense). Next, students consumed a buzz button and resampled each food item as well as re-rated their perceived taste intensities. It was found that students' perceived taste intensities for sour items and sweet items were decreased after consuming the buzz buttons. Additionally, students also completed a post-activity survey in which they indicated that this was an interesting and enjoyable exercise. This highlights the value of this particular hands-on demonstration in teaching about the connection between taste and tactile perception.

Sour taste perception in fluids: The impact of sweet tastant, fluid viscosity, and individual salivary properties.

Binary taste perception is widely studied in aqueous solutions but less investigated in non-Newtonian fluid systems. In this study, the effect of sweet tastants on the dynamic sour taste perception in thickened fluids and its underpinning oral processing factors were investigated. Subjects were tested for taste thresholds and salivary biochemical properties. By using hydroxypropyl methylcellulose (HPMC) as a thickening agent, subjects conducted sour taste evaluation, with and without maltose and/or HPMC, using descriptive sensory analyses. A simulated fluid shear elicited by fixed-frequency mastication was applied on thickened fluid sample oral processing during time-intensity sour taste evaluation. Results showed that adding maltose to fluid samples enhanced sour taste perception, and increasing fluid viscosity generally suppressed perceived maximum sour taste. Moreover, subjects with lower sour taste sensitivity and higher salivary buffering capacity reported overall lower sour taste intensity in most samples, validating the hypothesis that salivary properties importantly affect sour taste perception.

Amino Acid Bitterness: Characterization and Suppression.

Amino acids are necessary for life, and many must be consumed because they cannot be endogenously synthesized. Typically, we eat them as proteins and peptides, which have little taste. However, we also directly ingest free amino acids, several of which are aversive because they elicit bitterness. This bitterness often prevents many patient populations from taking formulas and supplements containing free amino acids. Here, we characterize which amino acids are the most bitter, their concentration-intensity functions, and individual differences in bitterness perception, and we explore how sodium salts suppress the bitterness of amino acids. We found that the essential amino acids comprise the most bitter stimuli, with six of them conveying the most bitterness. Clustering and correlating amino acids by individual differences in bitterness perception show that there are approximately four groupings of amino acids and suggest that within these clusters, amino acids may be activating the same or overlapping TAS2Rs. We also show that bitterness can be largely suppressed by sodium salts for 5 of the 6 most bitter amino acids. These results hold promise for managing the bitter taste of nutritional supplements that contain amino acids and improving compliance.

[Advances in bitterness receptors T2Rs in different diseases].

Bitterness, as one of the most important physiological sensations in animals, is primarily recognized through the mediation of bitter taste receptors. In recent years, it has been found that these receptors are not only expressed in taste bud cells on the tongue but also in the respiratory, cardiovascular, digestive, reproductive, and nervous systems. They are involved in regulating various fundamental physiological processes and are now considered important targets for the treatment of various diseases. This paper reviewed the structure, classification, distribution, and signaling pathways of bitter taste receptors, their relationship with different diseases, and the role of bitter taste receptors agonists, aiming to provide a basis for scientific research on bitter taste receptors.

FlavorDB2: An updated database of flavor molecules.

Flavor is expressed through the interaction of molecules via gustatory and olfactory mechanisms. Knowing the pivotal role of flavor molecules in food and fragrances, the existence of a comprehensive repository becomes valuable. Such a repository encompasses the information of flavor molecules characterizing their flavor profile, chemical properties, regulatory status, consumption statistics, taste/aroma threshold values, reported uses in food categories, and synthesis. FlavorDB2 (https://cosylab.iiitd.edu.in/flavordb2/) is an updated database of flavor molecules with a user-friendly interface consisting of 25,595 flavor molecules. Among these, 2254 flavor molecules are associated with 936 natural ingredients from 34 categories. This repository simplifies the search for flavor molecules and their associated attributes. This platform offers multifaceted applications, including food pairing. FlavorDB2 serves as a standard repository of flavor compounds for researchers, chefs, and fragrance industry.

Developing zebrafish utilize taste-signaling pathways for oxygen chemoreception.

A fundamental requirement for all animals is to sense and respond to changes in environmental O2 availability. Low O2 (hypoxia) typically stimulates breathing, a universal and critical response termed the hypoxic ventilatory response (HVR). In this study, we test the hypothesis that taste-signaling pathways are used for O2 sensing and activation of the HVR. We show that Merkel-like cells (MLCs), which are part of the taste-bud complex, function as O2 chemoreceptor cells in larval zebrafish and that transduction of the O2 signal uses taste-signaling pathways. Specifically, MLCs responded to hypoxia in vivo with an increase in Ca2+ activity that can drive the HVR. In addition, MLCs transmit O2 signals to afferent cranial nerves IX and X (nIX/X), which project into the area postrema within the hindbrain and synapse with interneurons that are in contact with vagal motor neurons. Hypoxia or chemo-activation of nIX/X caused Ca2+ activity to increase within the area postrema and elicited hyperventilation. The results provide the first demonstration of an O2 signaling pathway that commences with the activation of taste receptors (MLCs) to yield a critical physiological reflex, the HVR.

Synaptic connectome of a neurosecretory network in the Drosophila brain.

Hormones mediate inter-organ signaling which is crucial in orchestrating diverse behaviors and physiological processes including sleep and activity, feeding, growth, metabolism and reproduction. The pars intercerebralis and pars lateralis in insects represent major hubs which contain neurosecretory cells (NSC) that produce various hormones. To obtain insight into how hormonal signaling is regulated, we have characterized the synaptic connectome of NSC in the adult Drosophila brain. Identification of neurons providing inputs to multiple NSC subtypes implicates diuretic hormone 44-expressing NSC as a major coordinator of physiology and behavior. Surprisingly, despite most NSC having dendrites in the subesophageal zone (primary taste processing center), gustatory inputs to NSC are largely indirect. We also deciphered pathways via which diverse olfactory inputs are relayed to NSC. Further, our analyses revealed substantial inputs from descending neurons to NSC, suggesting that descending neurons regulate both endocrine and motor output to synchronize physiological changes with appropriate behaviors. In contrast to NSC inputs, synaptic output from NSC is sparse and mostly mediated by corazonin NSC. Therefore, we additionally determine putative paracrine interconnectivity between NSC subtypes and hormonal pathways from NSC to peripheral tissues by analyzing single-cell transcriptomic datasets. Our comprehensive characterization of the Drosophila neurosecretory network connectome provides a platform to understand complex hormonal networks and how they orchestrate animal behaviors and physiology.

Postoperative dysgeusia following microsurgical resection for acoustic neuroma: a systematic review and meta-analysis.

OBJECTIVE: To determine the collated rate of postoperative dysgeusia after microsurgical intervention in acoustic neuroma patients. METHODS: The systematic review with meta-analysis was undertaken following PRISMA guidelines. A thorough search of PubMed/Medline, the Cochrane Database of Systematic Reviews, and Epistemonikos was undertaken for studies published up until May 16, 2024 reporting postoperative taste disturbance rates after microsurgical intervention for acoustic neuroma. The methodological quality of the included studies was assessed via the Methodological Index for Non-Randomized research (MINORS) tool. Using MedCalc (v. 20.215) software, the random-effects model was developed for proportional meta-analysis. RESULTS: Eight studies, encompassing 2,402 patients (mean age = 49.06 years; 48.54% female population), were included in the analysis. The overall pooled rate of postoperative dysgeusia following microsurgical management of acoustic neuroma was 23.7% (95% CI: 9.266-42.359, p < 0.0001). When stratified by surgical approach, the rate of postoperative dysgeusia for the retrosigmoid approach was 18.8% (95% CI: 2.821-44.461, p < 0.0001). Postoperative dysgeusia data stratified for other major microsurgical approaches (subtemporal and translabirynthine approaches) was not reported by any of the included studies. CONCLUSION: Our systematic review and meta-analysis calculated a collated rate of almost 25% and recognized postoperative dysgeusia as a common complication following microsurgical management of acoustic neuromas. These results highlight the significance of preoperative counselling and the development of strategies that minimize the likelihood of harm to the chorda tympani nerve during microsurgical intervention for acoustic neuroma.

The duct of von Ebner's glands is a source of Sox10 + taste bud progenitors and susceptible to pathogen infections.

Introduction: We have recently demonstrated that Sox10-expressing (Sox10 +) cells give rise to mainly type-III neuronal taste bud cells that are responsible for sour and salt taste. The two tissue compartments containing Sox10 + cells in the surrounding of taste buds include the connective tissue core of taste papillae and von Ebner's glands (vEGs) that are connected to the trench of circumvallate and foliate papillae. Methods: In this study, we performed single cell RNA-sequencing of the epithelium of Sox10-Cre/tdT mouse circumvallate/vEG complex and used inducible Cre mouse models to map the cell lineages of vEGs and/or connective tissue (including stromal and Schwann cells). Results: Transcriptomic analysis indicated that Sox10 expression was enriched in the cell clusters of vEG ducts that contained abundant proliferating cells, while Sox10-Cre/tdT expression was enriched in type-III taste bud cells and vEG ductal cells. In vivo lineage mapping showed that the traced cells were distributed in circumvallate taste buds concurrently with those in the vEGs, but not in the connective tissue. Moreover, multiple genes encoding pathogen receptors were enriched in the vEG ducts hosting Sox10 + cells. Discussion: Our data supports that it is the vEGs, not connective tissue core, that serve as the niche of Sox10 + taste bud progenitors. If this is also true in humans, our data indicates that vEG duct is a source of Sox10 + taste bud progenitors and susceptible to pathogen infections.

Major Bitter-Tasting Compounds from the Dichloromethane Fraction of Bitter Gourd (Fruit of Momordica charantia L.) Extract and Their Precursors.

The unripe fruit of the plant Momordica charantia L., commonly known as bitter gourd or bitter melon, is a popular vegetable and medical herb in many parts of the world and is characterized by its strong bitter taste. In our endeavor to decode its bitter taste, the dichloromethane fraction of 75% methanol extract of bitter gourd was found to be intensely bitter. Combining sensory analysis-guided fractionation and newly developed comparative high-pressure liquid chromatography (HPLC) analysis-guided purification led to the isolation of five known compounds including momordicoside L (1), (23E)-3ß-O-malonyl-7ß,25-dihydroxycucurbita-5,23-dien-19-al (2), 3-O-ß-d-allopyranosyl-7ß,25-dihydroxycucurbita-5,23(E)-dien-19-al (3), momordicine IV (5), and charantoside B (6) and three new compounds 3-O-ß-d-3-ketoglucopyranosly-7ß,25-dihydroxycucurbita-5,23(E)-dien-19-al (4), 6'-O-malonylmomordicoside L (7), and 6'-O-malonylmomordicine IV (8) from bitter gourd. Sensory analysis revealed compounds 3-8 had strong bitter taste with their bitter taste recognition thresholds in the range between 3.6 (4) and 13.6 ppm (6) in 3% ethanol. UPLC-MS/MS quantification showed that their concentration in bitter gourd ranged from 16.5 ± 1.3 mg/kg (4) to 214.8 ± 14.0 mg/kg (6) on a dry weight basis. Calculation of the dose-over-threshold (DoT) factor showed that momordicine IV (5) and charantoside B (6) should be considered as bitter principles of bitter gourd. In addition, the study also demonstrated the ubiquity of the isomerization reaction in the side chain of cucurbitane-type triterpenoids. Many isolated compounds were the isomerized products of their natural precursors, and these precursors should be the primary bitterness contributors of fresh fruits. In addition, comparative HPLC analysis-guided purification could be a practical approach for the fast isolation of acid-labile precursors.

Extragustatory bitter taste receptors in head and neck health and disease.

Taste receptors, first described for their gustatory functions within the oral cavity and oropharynx, are now known to be expressed in many organ systems. Even intraoral taste receptors regulate non-sensory pathways, and recent literature has connected bitter taste receptors to various states of health and disease. These extragustatory pathways involve previously unexplored, clinically relevant roles for taste signaling in areas including susceptibility to infection, antibiotic efficacy, and cancer outcomes. Among other physicians, otolaryngologists who manage head and neck diseases should be aware of this growing body of evidence and its relevance to their fields. In this review, we describe the role of extragustatory taste receptors in head and neck health and disease, highlighting recent advances, clinical implications, and directions for future investigation. Additionally, this review will discuss known TAS2R polymorphisms and the associated implications for clinical prognosis.

Novel umami-enhancing peptides of beef M. Semimembranosus hydrolysates and interactions with the T1R1/T1R3 taste receptor.

The taste mechanisms of beef umami and umami-enhancing peptides are not well understood. Therefore, novel umami and umami-enhancing peptides from beef M. semimembranosus hydrolysates were explored. Beef hydrolysates treated with Flavourzyme® showed an overall strong umami intensity compared to those treated with Alcalase®, papain, or Protamex®. The peptides were isolated via consecutive separation processes, and 31 potential umami peptides were identified. Molecular docking results showed that WGSEPIRIQ and TERGYSF had considerably low docking energies with the T1R1/T1R3 taste receptor through potential key binding sites for hydrogen bonding, including Ser48, Gly49, and Gln278 in T1R1, and Ser67, Asn68, and Arg247 in the T1R3 subunit. The taste of the identified peptides dissolved in ultrapure water was dominated by sourness. Instead, they demonstrated an umami-enhancing effect in the presence of monosodium glutamate. These results broaden our understanding of the taste mechanisms of beef umami-enhancing peptides and their potential applications as flavoring agents.

Evolution of novel sensory organs in fish with legs.

How do animals evolve new traits? Sea robins are fish that possess specialized leg-like appendages used to "walk" along the sea floor. Here, we show that legs are bona fide sense organs that localize buried prey. Legs are covered in sensory papillae that receive dense innervation from touch-sensitive neurons, express non-canonical epithelial taste receptors, and mediate chemical sensitivity that drives predatory digging behavior. A combination of developmental analyses, crosses between species with and without papillae, and interspecies comparisons of sea robins from around the world demonstrate that papillae represent a key evolutionary innovation associated with behavioral niche expansion on the sea floor. These discoveries provide unique insight into how molecular-, cellular-, and tissue-scale adaptations integrate to produce novel organismic traits and behavior.

Sulfonated Azocalix[4]arene: A Universal and Effective Taste-Masking Agent.

Many active pharmaceutical ingredients have a specific bitter taste. To enhance patient compliance and treatment efficacy, taste-masking agents are crucial in oral drug formulations. Confronting numerous bitter drug molecules with varied structures, the pharmaceutical field strives to explore and develop universal and effective masking approaches. Here, we reported sulfonated azocalix[4]arene (SAC4A), a universal supramolecular masking agent with deep cavity that provides stronger hydrophobic effect and larger interaction area during recognition, allowing high binding affinity to bitter drug molecules. Moreover, bitter drugs could deeply buried in the cavity, with the bitterness effectively masked. As a result, SAC4A can bind to 16 different bitter drugs with high affinities, encompassing alkaloids, flavonoids, terpenoids, and more, while maintaining high biocompatibility. As anticipated, SAC4A effectively masks the unpalatable bitter taste associated with these drugs. Consequently, SAC4A is a promising universal and effective supramolecular masking agent.