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Summary: The emergence of kokumi sensation as a flavour enhancer prompted the search for cost effective and the sustainable production of kokumi flavour substances (KS), including small γ‐glutamyl peptides (GGP) and aromatic free amino acids (FAA). We sought to investigate the potential of mechanically deboned meat (MDM) from beef, mutton, lamb and venison for KS production through enzymatic γ‐glutamylation. Liquid chromatography‐mass spectrometry (LC–MS) and in vitro calcium‐sensing receptor (CaSR) activity assays were utilised to identify GGPs and their kokumi intensity, respectively. The enzymatic method significantly increased GGP and FAA in all MDM samples with differences in individual peptides across the species. Notably, all four sources of MDM activated CaSR in a dose‐dependent manner, displaying varying potency and efficacy levels. Beef, lamb and mutton showed a similar range of higher potency, while venison exhibited lower potency but higher efficacy. The thermal stability of γ‐glutamylated beef samples, used as an exemplar, was confirmed at temperatures of 80 °C, 120 °C and 150 °C. Given these findings, MDM represents a promising substrate for KS production and warrants further investigation to assess its practical applicability for enhancing kokumi flavour in the food industry. [ABSTRACT FROM AUTHOR]

The molecular basis of sweet taste toward various amino acids has not been fully elucidated. In this study, by correlation of their sweetness intensities with molecular properties, it is revealed that hydrophobic or dispersion force between side chains and sweet taste receptor (Tas1R2/Tas1R3) plays a prominent role for eliciting sweetness. Furthermore, the interaction modes of 13 amino acids with receptor indicate that amino (AH) and carboxyl (B) glucophores of different amino acids interact with identical residues of receptor, while the hydrophobic side chains (X glucophores) conduct distinct topological orientations with receptor, determining their chirality selection and sweetness intensities. Molecular dynamics analysis shows that sweet d‐amino acids move toward the hydrophobic transmembrane domain during activation with more contact numbers with receptor than nonsweet l‐amino acids, providing a mechanistic elucidation of previous inconsistent sensory evaluation results of specific amino acids. Moreover, by comparison with the interactions of a dipeptide sweetener, aspartame with Tas1R2/Tas1R3 and nonsweet l‐glutamate with class C G protein‐coupled receptors, we conclude that a complementary interaction mode with both hydrophilic and hydrophobic contacts accounts for the molecular origin of their sweet taste, presenting in‐depth insights and valuable guidelines for further molecular designs or modifications of amino acids‐derived sweeteners. [ABSTRACT FROM AUTHOR]

Bitter taste receptors (TAS2Rs) are not only expressed in the oral cavity but also in skin. Extraoral TAS2Rs are thought to be involved in non‐taste perception and tissue‐specific functions. Keratinocytes that express TAS2Rs in the skin provide a first‐line defense against external threats. However, the functional roles of these receptors in host defense remain unclear. Here, we demonstrated the sensory role of intracellularly located TAS2Rs against toxic substances in keratinocytes. Although many G protein‐coupled receptors elicit signals from the surface, TAS2Rs were found to localize intracellularly, possibly to the ER, in human keratinocytes and HaCaT cells. TAS2R38, one of the TAS2R members, activated the Gα12/13/RhoA/ROCK/p38 MAP kinase/NF‐κB pathway upon stimulation by phenylthiocarbamide (PTC), an agonist for this receptor, leading to the production of ABC transporters, such as ABCB1, in these cells. Notably, treatment with bitter compounds, such as PTC and saccharin, induced the upregulation of ABCB1 in HaCaT cells. Mechanistically, intracellular TAS2R38 and its downstream signaling Gα12/13/RhoA/ROCK/p38 MAP kinase/NF‐κB pathway were identified to be responsible for the above effect. Pretreatment with PTC prevented the accumulation of rhodamine 123 because of its excretion via ABCB1. Furthermore, pretreatment with PTC or saccharin counteracted the effect of the toxic compound, diphenhydramine, and pretreated HaCaT cells were found to proliferate faster than untreated cells. This anti‐toxic effect was suppressed by treatment with verapamil, an ABCB1 inhibitor, indicating that enhanced ABCB1 helps clear toxic substances. Altogether, harmless activators of TAS2Rs may be promising drugs that enhance the excretion of toxic substances from the human skin. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Cyclocarya paliurus, as a new food resource, is utilized extensively in human and animal diets due to its bioactive compounds, health benefits, and its highly prized sweet flavor. This study aimed to investigate the sweet‐taste ingredient of C. paliurus leaves.Five new dammarane triterpenoid glycosides were isolated and identified as qingqianliutianosides A–E (1–5) by comprehensive spectroscopic data analysis and a single crystal X‐ray diffraction experiment. Qingqianliutianoside A (1) and qingqianliutianoside C (3), present in relatively high quantities in the plant, were shown to exhibit sweetness by sensory evaluation and electronic tongue analysis. Further monitoring was conducted on the content changes in 3 in leaves at different growth stages, indicating that 3 reached its peak content in April and then showed a decreasing trend. Molecular docking studies revealed that T1R2/T1R3 receptors Ser212, Ser105, Thr239, Asn380, Thr305, and Val381 may play critical roles, demonstrating that hydrogen bonding and hydrophobic interactions were the dominant interaction forces between all of the identified compounds and the active sites in the Venus flytrap module of the T1R2/T1R3 receptors.Qingqianliutianosides A–E are promising natural source sugar substitutes for use in functional foods and beverages. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A proton (H+) channel, Otopetrin 1 (OTOP1) is an acid sensor in the sour taste receptor cells. Although OTOP1 is known to be activated by extracellular acid, no posttranslational modification of OTOP1 has been reported. As one of the posttranslational modifications, glycosylation is known to modulate many ion channels. In this study, we investigated whether OTOP1 is glycosylated and how the glycosylation affects OTOP1 function. Pharmacological and enzymatic examinations (using an N‐glycosylation inhibitor, tunicamycin and peptide: N‐glycanase F [PNGase F]) revealed that overexpressed mouse OTOP1 was N‐glycosylated. As the N‐glycans were Endoglycosidase H (Endo H)‐sensitive, they were most likely high‐mannose type. A site‐directed mutagenesis approach revealed that both two asparagine residues (N238 and N251) in the third extracellular loop between the fifth transmembrane region and the sixth transmembrane region (L5‐6) were the glycosylation sites. Prevention of the glycosylations by the mutations of the asparagine residues or by tunicamycin treatment diminished the whole‐cell OTOP1 current densities. The results of cell surface biotinylation assay showed that the prevention of the glycosylations reduced the surface expression of OTOP1 at the plasma membrane. These results indicate that mouse OTOP1 is N‐glycosylated at N238 and N251, and that the glycosylations are necessary for OTOP1 to show the maximum degree of H+ current densities at the plasma membrane through promoting its targeting to the plasma membrane. These findings on glycosylations of OTOP1 will be a part of a comprehensive understanding on the regulations of OTOP1 function. [ABSTRACT FROM AUTHOR]

Portable and personalized artificial intelligence (AI)‐driven sensors mimicking human olfactory and gustatory systems have immense potential for the large‐scale deployment and autonomous monitoring systems of Internet of Things (IoT) devices. In this study, an artificial Q‐grader comprising surface‐engineered zinc oxide (ZnO) thin films is developed as the artificial nose, tongue, and AI‐based statistical data analysis as the artificial brain for identifying both aroma and flavor chemicals in coffee beans. A poly(vinylidene fluoride‐co‐hexafluoropropylene)/ZnO thin film transistor (TFT)‐based liquid sensor is the artificial tongue, and an Au, Ag, or Pd nanoparticles/ZnO nanohybrid gas sensor is the artificial nose. In order to classify the flavor of coffee beans (acetic acid (sourness), ethyl butyrate and 2‐furanmethanol (sweetness), caffeine (bitterness)) and the origin of coffee beans (Papua New Guinea, Brazil, Ethiopia, and Colombia‐decaffeine), rational combination of TFT transfer and dynamic response curves capture the liquids and gases‐dependent electrical transport behavior and principal component analysis (PCA)‐assisted machine learning (ML) is implemented. A PCA‐assisted ML model distinguished the four target flavors with >92% prediction accuracy. ML‐based regression model predicts the flavor chemical concentrations with >99% accuracy. Also, the classification model successfully distinguished four different types of coffee‐bean with 100% accuracy. [ABSTRACT FROM AUTHOR]

Increased sugar concentrations on mucosal surfaces display risk factors for infections. This study aims to clarify sugar monitoring in the urethra. Urethral tuft cells (UTC) are known sentinels monitoring the urethral lumen for potentially harmful substances and initiating protective mechanisms. Next‐generation sequencing (NGS), RT‐PCR, and immunohistochemistry show expression of the taste receptor Tas1R3 in murine UTC, a crucial component of the classical sweet detection pathway. Isolated UTC respond to various sugars with an increase of intracellular [Ca2+]. The Tas1R3 inhibitor gurmarin and Tas1R3 deletion reduces these responses. Utilizing mice lacking UTC, glibenclamide, a K+‐ATP channel antagonist, and phlorizin, a SGLT1 inhibitor, reveal an additional Tas1R3 independent sweet detection pathway. Inhibition of both pathways abrogates the sugar responses. Rat cystometry shows that intraurethral application of sucrose and glucose increases detrusor muscle activity Tas1R3 dependently. Sugar monitoring in the urethra occurs via two distinct pathways. A Tas1R3 dependent pathway, exclusive to UTC, and a Tas1R3 independent sweet detection pathway, which can be found both in UTC and in other urethral epithelial cells. [ABSTRACT FROM AUTHOR]

Bitter taste involves the detection of diverse chemical compounds by a family of G protein‐coupled receptors, known as taste receptor type 2 (TAS2R). It is often linked to toxins and harmful compounds and in particular bitter taste receptors participate in the regulation of glucose homeostasis, modulation of immune and inflammatory responses, and may have implications for various diseases. Human TAS2Rs are characterized by their polymorphism and differ in localization and function. Different receptors can activate various signaling pathways depending on the tissue and the ligand. However, in vitro screening of possible TAS2R ligands is costly and time‐consuming. For this reason, in silico methods to predict bitterant‐TAS2R interactions could be powerful tools to help in the selection of ligands and targets for experimental studies and improve our knowledge of bitter receptor roles. Machine learning (ML) is a branch of artificial intelligence that applies algorithms to large datasets to learn from patterns and make predictions. In recent years, there has been a record of numerous taste classifiers in literature, especially on bitter/non‐bitter or bitter/sweet classification. However, only a few of them exploit ML to predict which TAS2R receptors could be targeted by bitter molecules. Indeed, the shortage and incompleteness of data on receptor‐ligand associations in literature make this task non‐trivial. In this work, we provide an overview of the state of the art dealing with this specific investigation, focusing on three ML‐based models, namely BitterX (2016), BitterSweet (2019) and BitterMatch (2022). This review aims to establish the foundation for future research endeavours focused on addressing the limitations and drawbacks of existing models. [ABSTRACT FROM AUTHOR]

The throat is an organ that includes the larynx, esophagus, and bronchi. Vocalization or deglutition triggers micro‐movements of muscles around the throat. In this study, based on machine learning using a flexible patch, pronunciation is identified by analyzing the vibration and movement of the laryngeal muscles, and the type of food consumed is determined through peristalsis analysis. Previously, voices are recognized through cochlea hair cells, and the type of food intake is identified through taste receptors. However, this study converted auditory or gustatory senses to tactile stage through sensory transition and finally visualized. Using a customized throat patch with segmented nodes, the pronunciation of [a], [e], [i], [o], and [u], representative vowels of languages worldwide, are distinguished with an accuracy of 85.9% based on the polynomial kernel algorithm. In addition, cookies, water, gummies, and chocolate are distinguished with 91.1% accuracy by detecting differences in the esophagus's peristalsis. Transformation of auditory or gustatory sensations to tactile information and visualization is expected to be used for communication in noisy environments or soundless environments such as outer space. This approach can also provide significant potential for determining the type of ingestion for users who have lost their sense of taste. [ABSTRACT FROM AUTHOR]

BACKGROUND: Non‐nutritive sweeteners (such as sucralose) bind to sweet receptors Tas1r2/Tas1r3 on intestinal endocrine L cells after diets to upregulate blood glucose. However, the mechanism by which sucralose regulates postprandial blood glucose (PBG) has not been clarified to date. We hypothesized that the gut sweet taste receptor was one of the targets for sucralose to regulate PBG. The aim of this study was to examine the effect of sucralose on PBG based on the gut sweet taste receptor signaling pathway and to explore the mechanism. Therefore, we examined PBG, genes, and proteins associated with the gut sweet receptor pathway in sucralose‐exposed mice. RESULTS: The results showed that after 12 weeks of sucralose exposure the PBG of mice increased significantly, and the expression of intestinal sweet taste receptors increased correspondingly. Within the concentration range of this experiment, a significant increase of PBG was observed in mice fed on sucralose with a concentration equal to or higher than 0.33 g L−1. CONCLUSION: Long‐term consumption of sucralose may increase body weight and the risk of elevated PBG, resulting in overexpression of sweetness receptors and glucose transporters. The mechanism of these effects might be the result of non‐nutritive sweeteners binding to sweetness receptors Tas1r2/Tas1r3 in gut endocrine cells and upregulating Slc5a1 and Slc2a2. But we cannot rule out that the rise in PBG is the result of a combination of sweet receptors and gut microbes. Therefore, the effect of gut microbes on PBG needs to be studied further. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A large portion of the human GPCRome is still in the dark and understudied, consisting even of entire subfamilies of GPCRs such as odorant receptors, class A and C orphans, adhesion GPCRs, Frizzleds and taste receptors. However, it is undeniable that these GPCRs bring an untapped therapeutic potential that should be explored further. Open questions on these GPCRs span diverse topics such as deorphanisation, the development of tool compounds and tools for studying these GPCRs, as well as understanding basic signalling mechanisms. This review gives an overview of the current state of knowledge for each of the diverse subfamilies of understudied receptors regarding their physiological relevance, molecular mechanisms, endogenous ligands and pharmacological tools. Furthermore, it identifies some of the largest knowledge gaps that should be addressed in the foreseeable future and lists some general strategies that might be helpful in this process. [ABSTRACT FROM AUTHOR]

Type 2 taste receptors (TAS2Rs), traditionally known for their role in bitter taste perception, are present in diverse reproductive tissues of both sexes. This review explores our current understanding of TAS2R functions with a particular focus on reproductive health. In males, TAS2Rs are believed to play potential roles in processes such as sperm chemotaxis and male fertility. Genetic insights from mouse models and human polymorphism studies provide some evidence for their contribution to male infertility. In female reproduction, it is speculated that TAS2Rs influence the ovarian milieu, shaping the functions of granulosa and cumulus cells and their interactions with oocytes. In the uterus, TAS2Rs contribute to uterine relaxation and hold potential as therapeutic targets for preventing preterm birth. In the placenta, they are proposed to function as vigilant sentinels, responding to infection and potentially modulating mechanisms of fetal protection. In the cervix and vagina, their analogous functions to those in other extraoral tissues suggest a potential role in infection defense. In addition, TAS2Rs exhibit altered expression patterns that profoundly affect cancer cell proliferation and apoptosis in reproductive cancers. Notably, TAS2R agonists show promise in inducing apoptosis and overcoming chemoresistance in these malignancies. Despite these advances, challenges remain, including a lack of genetic and functional studies. The application of techniques such as single‐cell RNA sequencing and clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR‐associated endonuclease 9 gene editing could provide deeper insights into TAS2Rs in reproduction, paving the way for novel therapeutic strategies for reproductive disorders. [ABSTRACT FROM AUTHOR]

Objective: To investigate differences in angiotensin‐converting‐enzyme‐2 (ACE2) and bitter taste receptor (TAS2R38) expression between patient age groups and comorbidities to characterize the pathophysiology of coronavirus 19(COVID‐19) pandemic. ACE2 is the receptor implicated to facilitate SARS‐CoV‐2 infections and levels of expression may correlate to the severity of COVID‐19 infection. TAS2R38 has many non‐gustatory roles in disease, with some evidence of severe COVID‐19 disease in certain receptor phenotypes. Methods: We conducted a prospective cohort study and collected nasal and lingual tissue from healthy pediatric (n = 22) and adult (n = 25) patients undergoing general anesthesia for elective procedures. RNA isolation and qPCR were performed with primers targeting ACE2 and TAS2R38. Results: A total of 25 adult (52% male; 44% obese) and 22 pediatric (50% male; 36% obese) patients were enrolled, pediatric tissue had 43% more nasal ACE2 RNA expression than adults with a median fold change of 0.69 (IQR 0.37, 0.98) in adults and 0.99 (IQR 0.74, 1.43) in children (p <.05). There were no differences between the age groups in ACE2 expression of lingual tissue (p =.14) or TAS2R38 expression collected from either nasal (p = 049) or lingual tissue (p =.49). Stratifying for obesity yielded similar differences between nasal ACE2 expression between adults and children with median fold change of 0.56 (IQR 0.32, 0.87) in adults and 1.0 (IQR 0.82, 1.52) in children (p <.05). Conclusions: ACE2 receptor expression is higher in nasal tissue collected from children compared to adults, suggesting COVID‐19 infectivity is more complicated than ACE2 and TAS2R38 mRNA expression. Level of Evidence: NA. [ABSTRACT FROM AUTHOR]

Taste sensitivity in humans varies due to quantitative and qualitative differences in the structure of the sense‐perception organs. Taste perception is caused by the interaction of peripheral chemosensory organs, transmitted from the taste receptors of the taste buds on the tongue to the brain. Interestingly, taste receptors, which are classified into four types, are not only found in the oral cavity; they are also present at extraoral sites. Taste receptor type 1 (TAS1R) and type 2 (TAS2R) regulate bone remodeling. This review focuses on the effects of TAS1R1, TAS2R, TAS1R2, and TAS1R3, all of which belong to the family of G‐protein‐coupled receptors (GPCRs) related to bone remodeling. A summary of the clinical evidence that taste receptors play an essential role in bone remodeling is also provided. [ABSTRACT FROM AUTHOR]

Bitterness elicits unpleasant sensations in humans, which can hinder the acceptance of foods and medication adherence. Therefore, identifying and masking bitter tastes is crucial for developing palatable foods and promoting medication compliance in the food and pharmaceutical industries. To achieve this, employing agonism and antagonism of bitter taste receptors as effective strategies at the molecular level is essential. In this study, a bioelectronic tongue is developed to characterize the agonism and antagonism of bitter taste receptors. The human bitter taste receptors hTAS2R16 and hTAS2R31 are produced using an Escherichia coli expression system and reconstituted into nanodiscs (NDs). Subsequently, hTAS2R16‐ and hTAS2R31‐NDs are immobilized on the surface of graphene field‐effect transistors (FETs) to construct bioelectronic tongues. The developed system sensitively detected the bitter agonists, salicin and saccharin, at concentrations as low as 100 fM, with high selectivity in real‐time. The dose‐dependent curves shifted and K values decreased by the antagonists of hTAS2R16 and hTAS2R31, indicating antagonism‐based masking of bitter taste. Therefore, the developed bioelectronic tongue holds promise for identifying bitter tastes and evaluating the masking of bitterness based on the agonism and antagonism of hTAS2Rs. [ABSTRACT FROM AUTHOR]

To investigate the antidiabetic effects and mechanisms of quinoa on type 2 diabetes mellitus (T2DM) mice model. In this context, we induced the T2DM mice model with a high‐fat diet (HFD) combined with streptozotocin (STZ), followed by treatment with a quinoa diet. To explore the impact of quinoa on the intestinal flora, we predicted and validated its potential mechanism of hypoglycemic effect through network pharmacology, molecular docking, western blot, and immunohistochemistry (IHC). We found that quinoa could significantly improve abnormal glucolipid metabolism in T2DM mice. Further analysis showed that quinoa contributed to the improvement of gut microbiota composition positively. Moreover, it could downregulate the expression of TAS1R3 and TRPM5 in the colon. A total of 72 active components were identified by network pharmacology. Among them, TAS1R3 and TRPM5 were successfully docked with the core components of quinoa. These findings confirm that quinoa may exert hypoglycemic effects through gut microbiota and the TAS1R3/TRPM5 taste signaling pathway. [ABSTRACT FROM AUTHOR]

The perceptual behavior of consumers on a product displayed in the market has a vital role in analyzing the importance given to that product. Therefore, various strategies have been developed to understand this consumer behavior in the selection of products. Immersive technologies like virtual, augmented, and mixed reality are among them. With the foremost feature of immersion in the virtual world and interaction of users with virtual objects, virtual reality, and augmented reality have unlocked their potential in research and a user‐friendly tool for analyzing consumer behavior. In addition to these technologies, mixed reality also has a significant role in investigating consumer behavior. Studies on immersive technologies in food applications are vast, hence this review focuses on the applications of virtual, augmented, and mixed reality in the food selection behavior of consumers. The behavioral studies are elicited to develop new products based on consumer needs, to understand the shopping behavior in supermarkets for real‐time usage, and to know the influence of emotions in a selection of products. The findings suggest that virtual, augmented, and mixed reality induce immersion of the users in food selection behavioral studies. Information on the technological advancements in the tools used for bringing immersion and interaction are discussed for its futuristic applications in food. Though immersive technology gives users a realistic virtual environment experience, its application in food systems is in the budding stage. More research on human response studies would contribute to its innovative and inevitable application in the future. [ABSTRACT FROM AUTHOR]

Bitter taste perception plays an important role in preventing animals from digesting poisonous and harmful substances. In primates, especially the Cercopithecidae species, most species feed on plants; thus, it is reasonable to speculate that most of the bitter taste receptor genes (T2Rs) of primates are under purifying selection to maintain the functional stability of bitter taste perception. Gene duplication has happened in T2Rs frequently, and what will be the fate of T2Rs copies is another question we are concerned about. To answer these questions, we selected the T2Rs of primates reported in another study and conducted corresponding selective pressure analyses to determine what kind of selective pressure was acting on them. Further, we carried out selective pressure analyses on gene copies and their corresponding ancestors by considering several possible situations. The results showed that among the 25 gene groups examined here, 15 groups are subject to purifying selection and others are under relaxed selection, with many positively selected sites detected. Gene copies existed in several groups, but only some groups (clade1_a1‐b2, clade1_c‐c2, clade1_d1‐d3, clade1_f1‐f2, T2R10, T2R13, and T2R42) have positively selected sites, inferring that they may have some relation to functional divergence. Taken together, T2Rs in primates are under diverse selective pressures, and most gene copies are subject to the same selective pressures. In such cases, the copies may be just to keep the function conservative, and more copies can increase the quantity of the bitter taste receptor, raise the efficiency of bitter substance recognition, and finally enhance the fitness of feeding during the evolutionary course of primates. This study can improve our understanding of T2Rs evolution in primates. [ABSTRACT FROM AUTHOR]

As an economically important herbivorous fish, the range of grass carp (Ctenopharyngodon idella) has expanded in the world and its ecological influences have become more evident. Currently, we have embarked on assessing the effect of grass carp on aquatic organisms and water quality by integrating the outcomes from previous ecological studies. Bibliographical data integration shows that aquatic plant preference is likely to be related to the cellulose proportion, calcium, sucrose and citric acid of the aquatic plant. Moreover, pharyngeal teeth and multiple gene copies of taste receptors could help reveal the feeding mechanism of grass carp. The expansion of the number of sweet‐detecting T1R2 genes, and the functional potential of Umami taste receptor T1R3 by calcium‐regulation was speculated on the basis of previous experimental observations of grass carp, suggesting that aquatic plant consumption by this species is tightly associated with the taste receptors. Apart from the competition in living space between grass carp and other fish, the effects of consuming zooplankton and zoobenthos were summarized to reveal general passive feeding of grass carp, as well as the feeding choice in the absence of aquatic plants. Water quality data were gleaned to make comparative analyses between groups stocking with and without grass carp to uncover changes in water physicochemical parameters in short‐ (<1 year) and long‐term impacts. This review provides insight into the grass carp feeding behaviour and mechanisms and it will help find a balance between ecological harmony and the industrial development of grass carp. [ABSTRACT FROM AUTHOR]

Aim: Obesity is a major public health issue, which is associated with several chronic diseases. In rodents, voluntary wheel running (VWR) is a type of exercise that influences ingestive behavior. This study aims to investigate the possible function of VWR activity in the perception of fat taste and if it mitigates the immediate effects of fatty acid (FA) ingestion. Methods: Male C57BL/6 mice were arbitrarily assigned to either a sedentary (SED) lifestyle or free access to a running wheel after 5 weeks of dietary regimen. Later these mice groups were used in the investigations on fat preference, metabolic tolerance, and electrophysiology. Diet‐induced alterations in CD36 and GPR120 expression that are related to fat perception and the capacitative calcium signaling caused by FA in taste bud cells (TBCs) were also examined. Results: In obese groups, VWR temporarily reduced body weight, demonstrated improvement in preference scores for FA, and recovered from a deterioration in glucose homeostasis. In CD36‐positive TBCs, electrophysiological investigations showed alterations in [Ca2+]i caused by FA. Further, in the TBCs of circumvallate papillae, there are differences in the expression of the genes CD36 and GPR120 between the active and SED controls. Obese mice also show lower incentive salience for long‐chain fatty acids (LCFA) and adapted to the reward system of VWR which may lead to improved incentive salience accredited to wheel running. Conclusion: In conclusion, this study provides the first evidence that VWR causes orosensory adaptations to fat and appears to alter taste preference for LCFAs. [ABSTRACT FROM AUTHOR]

Citrus is an important source of flavonoids in our daily diet. Citrus flavonoids have antioxidant, anticancer, anti‐inflammatory, and cardiovascular disease prevention functions. Studies have shown that some pharmaceutical values of flavonoids may be related to their binding to bitter taste receptors, thus activating downstream signal transduction pathways; however, the underlying mechanism has not been systematically elucidated. In this paper, the biosynthesis pathway and the absorption and metabolism of citrus flavonoids were briefly reviewed, and the relationship between flavonoid structure and bitter taste intensity was investigated. In addition, the pharmacological effects of bitter flavonoids and the activation of bitter taste receptors in combating various diseases were discussed. This review provides an important basis for the targeted design of citrus flavonoid structures to make them more biologically active and more attractive as powerful drugs for the effective treatment of chronic diseases such as obesity, asthma, and neurological diseases. [ABSTRACT FROM AUTHOR]

Thanks to the gustatory system, humans can experience the flavors in foods and drinks while avoiding the intake of some harmful substances. Although great advances in the fields of biotechnology, microfluidics, and nanotechnologies have been made in recent years, this astonishing recognition system can hardly be replaced by any artificial sensors designed so far. Here, taste organoids are coupled with an extracellular potential sensor array to form a novel bioelectronic organoid and developed a taste organoids-on-a-chip system (TOS) for highly mimicking the biological sense of taste ex vivo with high stability and repeatability. The taste organoids maintain key taste receptors expression after the third passage and high cell viability during 7 days of on-chip culture. Most importantly, the TOS not only distinguishs sour, sweet, bitter, and salt stimuli with great specificity, but also recognizes varying concentrations of the stimuli through an analytical method based on the extraction of signal features and principal component analysis. It is hoped that this bioelectronic tongue can facilitate studies in food quality controls, disease modelling, and drug screening. [ABSTRACT FROM AUTHOR]

In vertebrates, nutritional tastants, such as amino acids and sugars, are recognized by G‐protein‐coupled receptors of the taste receptor type 1 (T1R) family. Previous studies have shown that fish T1Rs are functionally distinct from mammalian T1Rs in certain regards. Here, we report the existence of oral receptors with high sensitivity to amino acids in zebrafish and medaka fish. We describe the construction of multiple cell lines stably expressing functional T1Rs (from medaka fish or zebrafish) with a chimeric G‐protein (G16gust44) using the Flp‐In system. Through functional assays with these cell lines, medaka fish and zebrafish were confirmed to possess particular T1Rs highly sensitive to l‐proline, possibly reflecting the physiological importance of l‐proline in teleosts, in line with previous studies. [ABSTRACT FROM AUTHOR]

For health and safety concerns, traditional high‐calorie sweeteners and artificial sweeteners are gradually replaced in food industries by natural and low‐calorie sweeteners. As a natural and high‐quality sugar substitute, steviol glycosides (SvGls) are continually scrutinized regarding their safety and application. Recently, the cultivation of organic stevia has been increasing in many parts of Europe and Asia, and it is obvious that there is a vast market for sugar substitutes in the future. Rebaudioside A, the main component of SvGls, is gradually accepted by consumers due to its safe, zero calories, clear, and sweet taste with no significant undesirable characteristics. Hence, it can be used in various foods or dietary supplements as a sweetener. In addition, rebaudioside A has been demonstrated to have many physiological functions, such as antihypertension, anti‐diabetes, and anticaries. But so far, there are few comprehensive reviews of rebaudioside A. In this review article, we discuss the physicochemical properties, metabolic process, safety, regulatory, health benefits, and biosynthetic pathway of rebaudioside A and summarize the modification methods and state‐of‐the‐art production and purification techniques of rebaudioside A. Furthermore, the current problems hindering the future production and application of rebaudioside A are analyzed, and suggestions are provided. [ABSTRACT FROM AUTHOR]

The bitter taste is generally considered an undesirable sensory attribute. However, bitter‐tasting compounds can significantly affect the overall flavor of many foods and beverages and endow them with various beneficial effects on human health. To better understand the relationship between chemical structure and bitterness, this paper has summarized the bitter compounds in foodstuffs and classified them based on the basic skeletons. Only those bitter compounds that are confirmed by human sensory evaluation have been included in this paper. To develop food products that satisfy consumer preferences, correctly ranking the key bitter compounds in foodstuffs according to their contributions to the overall bitterness intensity is the precondition. Generally, three methods were applied to screen out the key bitter compounds in foods and beverages and evaluate their sensory contributions, including dose‐over‐threshold factors, taste dilution analysis, and spectrum descriptive analysis method. This paper has discussed in detail the mechanisms and applications of these three methods. Typical procedures for separating and identifying the main bitter compounds in foodstuffs have also been summarized. Additionally, the activation of human bitter taste receptors (TAS2Rs) and the mechanisms of bitter taste transduction are outlined. Ultimately, a conclusion has been drawn to highlight the current problems and propose potential directions for further research. [ABSTRACT FROM AUTHOR]

Summary: Taste sensation enables humans to make nutritionally important decisions such as food preference and consumption. It functions as deterministic factors for unpropitious eating behavior, leading to overweight and obesity. The hedonistic feeling on consumption of fat and sugar‐rich meals, in particular, has a negative influence on health. In addition, impairment in the taste receptors alters the downstream signaling of taste transduction pathway. Hence, genetic polymorphism in typical taste receptors is a predictor of taste sensitivity variance across individuals. The present review summarizes the effect of a single nucleotide polymorphism (SNP) in sweet taste receptors (T1R2/T1R3) on taste perception among individuals of various body mass index (BMI). Furthermore, in the context of obesity, we discussed the possibility of crosstalk between fat and sweet receptors as well as taste dysfunction in diseased individuals. In overall, a greater understanding of the physiological relationship between taste receptors, altered taste sensitivity, and genetic polymorphisms should lead to more effective obesity prevention approaches. [ABSTRACT FROM AUTHOR]

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Fat taste perception has long been concerned in the regulation of dietary fat intake. Substantial experimental evidence defends fat as a sixth taste modality, but its allied peripheral mechanisms are not yet well established. The present study aimed to analyse the diet‐induced changes in fat taste perception and its associated physiological variations in Mus booduga. Four groups of animals were used for the present study and were fed any one of the following diet; normal diet (10% fat), low‐fat diet (4% fat), high‐fat diet (36% fat), or high‐fat diet (HFD) (36% fat) + rapeseed oil (HFRDO) (14%) for 9 weeks. The animals were then subjected to metabolic tolerance, fat preference, and conditioned taste aversion studies. Diet‐induced alterations in the expression of genes associated with lipogenesis, inflammation, and fat taste (CD36 and GPR120) were analysed. Capacitative calcium signalling induced by both linoleic acid and grifolic acid in taste bud cells (TBCs) was also analysed. In result, both the HFD and HFDRO groups revealed deterioration in glucose homoeostasis and displayed decreased preference scores for fatty acids, which are associated with lower CD36 expression and increased GPR120 expression in TBCs. Furthermore, change in [Ca2+]i induced by LA was also compromised in CD36 positive TBCs along with elevated systemic inflammatory and lipidemic responses in both these obese groups. Overall, for the first time, our results support that chronic HFD feeding alters the CD36 and GPR120 mediated fat taste perception in M. booduga. [ABSTRACT FROM AUTHOR]

Summary: In this study, a novel starch was isolated from bitter vetch and its chemical composition, morphology, particle size of the granules, swelling power and solubility, Fourier transformed infrared (FTIR) spectroscopy, X‐ray diffraction (XRD) and rheological, pasting and thermal properties were compared with conventional starches (corn, potato and chickpea). Micrographs exhibited that bitter vetch starch has oval, kidney or irregularly shaped granules with an average size of 28.5 μm. The XRD showed a C‐type pattern with 28.14% crystallinity. Bitter vetch starch had the highest amylose content (33.54%), pasting temperature (77.28 °C) and final viscosity (4983 cP) compared with other starch samples. Also, the storage and loss moduli in bitter vetch starch were higher than corn starch, which suggested bitter vetch starch as a promising new source of starch. [ABSTRACT FROM AUTHOR]

The chemical senses of olfaction and taste are well developed in fish and play a vital role in its various activities such as navigation, mate recognition, and food detection. The small teleost fish Astyanax mexicanus consists of interfertile river‐dwelling and cave‐dwelling populations, referred to as "surface fish" and "cavefish" respectively. An important anatomical feature of cavefish is the lack of eyes leading them to be referred to as blind fish and suggesting an enhanced functional role for other senses such as taste. In this study, we characterize the expression of bitter taste receptors (T2Rs or Tas2Rs) in A. mexicanus and investigate their functionality in a heterologous expression system. The genome database of A. mexicanus (ensemble and NCBI) showed 7 Tas2Rs, among these Tas2R1, Tas2R3, Tas2R4, and Tas2R114 are well characterized in humans and mice but not in A. mexicanus. Therefore, the 4 Tas2Rs were selected for further analysis and their expression in A. mexicanus was confirmed by in situ hybridization and RT‐PCR in early developmental stages. These Tas2Rs are expressed in various oral and extraoral organs (liver, fins, jaws, and gills) in A. mexicanus, and Tas2R1 has maximum expression and is localized throughout the fish body. Using the heterologous expression of A. mexicanus T2Rs in HEK293T cells coupled with cell‐based calcium mobilization assays, we show that A. mexicanus T2Rs are activated by commonly used fish food and known bitter agonists, including quinine. This study provides novel insights into the extraoral expression of T2Rs in A. mexicanus and suggests their importance in extraoral food detection. [ABSTRACT FROM AUTHOR]

Recently, demand for food products enriched with protein isolates, hydrolysates or peptides with immunomodulatory and anticancer activities derived from different plant sources has increased. Bitter taste inhibiting agents for whey protein hydrolysate and whey protein hydrolysate beverages. Functionality and applications of protein hydrolysates and peptides produced by single or combinations of various enzymes from proteins from different sources is not studied in depth. In conclusion, dry separation methods that can produce protein concentrates having protein content comparable to protein isolates produced by wet separation from different plant sources are required to be developed. [Extracted from the article]

Preclinical studies in animal models of obesity and inflammation have shown that oral administration of ARD‐101, a potential TAS2R agonist, reduced food intake and body weight and downregulated inflammatory cytokines. We present results from a first‐in‐human phase 1 randomized, placebo‐controlled trial that evaluated safety, pharmacokinetics, and pharmacodynamics of single or multiple ascending doses of oral ARD‐101 (40, 100, and 240 mg) in healthy adults. A total of 43 subjects were randomly assigned and dosed to ARD‐101 or placebo with 42 subjects completing the study treatment. ARD‐101 was found to be >99% restricted to the gut with minimal systemic exposure, demonstrated a favorable safety profile, and was well tolerated at all dose levels. Blood samples taken 1 hour after administration showed that subjects dosed with 240 mg of ARD‐101 had elevated circulating levels of several gut peptide hormones. It is postulated that ARD‐101 activates enteroendocrine cells to achieve its effects regulating metabolism and inflammation. The phase 1 clinical results demonstrated safety of ARD‐101 and indicated activation of gut peptide hormone release in healthy adults. Further clinical trials will evaluate ARD‐101 in patients with metabolic and inflammatory disorders. [ABSTRACT FROM AUTHOR]

Background: Eosinophilic inflammation is a hallmark of refractory chronic rhinosinusitis (CRS) and considered a major therapeutic target. Autophagy deficiency in myeloid cells plays a causal role in eosinophilic CRS (ECRS) via macrophage IL‐1β overproduction, thereby suggesting autophagy regulation as a potential therapeutic modality. Trehalose is a disaccharide sugar with known pro‐autophagy activity and effective in alleviating diverse inflammatory diseases. We sought to investigate the therapeutic potential of autophagy‐enhancing agent, trehalose, or related sugar compounds, and the underlying mechanism focusing on macrophage IL‐1β production in ECRS pathogenesis. Methods: We investigated the therapeutic effects of trehalose and saccharin on macrophage IL‐1β production and eosinophilia in the mouse model of ECRS with myeloid cell‐specific autophagy‐related gene 7 (Atg7) deletion. The mechanisms underlying their anti‐inflammatory effects were assessed using specific inhibitor, genetic knockdown or knockout, and overexpression of cognate receptors. Results: Unexpectedly, trehalose significantly attenuated eosinophilia and disease pathogenesis in ECRS mice caused by autophagy deficiency in myeloid cells. This autophagy‐independent effect was associated with reduced macrophage IL‐1β expression. Various sugars recapitulated the anti‐inflammatory effect of trehalose, and saccharin was particularly effective amongst other sugars. The mechanistic study revealed an involvement of sweet taste receptor (STR), especially T1R3, in alleviating macrophage IL‐1β production and eosinophilia in CRS, which was supported by genetic depletion of T1R3 or overexpression of T1R2/T1R3 in macrophages and treatment with the T1R3 antagonist gurmarin. Conclusion: Our results revealed a previously unappreciated anti‐inflammatory effect of STR agonists, particularly trehalose and saccharin, and may provide an alternative strategy to autophagy modulation in the ECRS treatment. [ABSTRACT FROM AUTHOR]

Background: Bitter and sweet taste receptors (T2Rs and T1Rs), respectively, are involved in the innate immune response of the sinonasal cavity and associated with chronic rhinosinusitis (CRS). Growing evidence suggests extraoral TRs as relevant biomarkers, but the current understanding is incomplete. This systematic review synthesizes current evidence of extraoral taste receptors in CRS. Methods: PubMed, Embase, Cochrane, Web of Science, and Scopus were reviewed in accordance with Preferred Reporting Items for Systemic Reviews and Meta‐Analyses guidelines and included studies of genotypic and phenotypic T2R/T1R status in CRS patients. Results: Twenty‐two studies with 3845 patients were included. Seventeen studies evaluated genotype and 10 evaluated taste phenotypes. Four of 6 studies examining the haplotype distribution of the T2R, TAS2R38, demonstrated increased AVI/AVI haplotype ("nontaster") frequency in CRS. Meanwhile, 2 studies demonstrated decreased bitter sensitivity in CRS with nasal polyposis (CRSwNP), whereas 3 other studies reported decreased bitter sensitivity only in CRS without nasal polyposis (CRSsNP). Findings regarding sweet sensitivity were mixed. Three studies with cystic fibrosis patients (n = 1393) were included. Studies investigating the association between clinical outcomes and TAS2R38 alleles were limited, but the nonfunctional combination of AVI/AVI was associated with increased utilization of sinus surgery and, in CRSsNP patients, with poorer improvement of symptoms postoperatively. Conclusion: Both genotypic and phenotypic assessments of T2Rs suggest a potential association with CRS, particularly CRSsNP. However, limited evidence and mixed conclusions cloud the role of T2Rs in CRS. Future investigations should aim to increase diverse populations, broaden institutional diversity, examine T1Rs, and utilize uniform assessments. [ABSTRACT FROM AUTHOR]

A relationship has recently been suggested to exist between tongue pressure measured using balloon‐type sensors and the tongue‐crushable food range of individuals. This study was conducted to investigate the applicability of a balloon‐type pressure sensor for texture evaluation of tongue‐crushable soft foods. Six gellan gum gels were used as a soft food model. The fracture force and strain of gels were controlled at two and three levels by changing the gum concentration and acyl‐group content, respectively. The pressure sensor was inserted between a food sample and texture analyzer probe, and pressure values during compression of gels were measured. During the compression test, both the food and tongue‐pressure sensor were deformed, eventually leading to fracture of food gels. Using the tongue‐pressure sensor, the food gels fractured at lower force because of the shape of the sensor but showed longer displacement as the sensor deformed compared to without the sensor. Gels with low‐fracture force in the conventional test without the sensor exhibited lower fracture force, work, gradient, and true stress than those with high‐fracture force in the sensor test. Displacement, clearance, or distance from the bottom plate, and true stress at fracture were appropriate parameters for expressing the fracture characteristics. Both the true fracture stress and fracture pressure in the sensor test decreased with the fracture strain of gels in a conventional test. These results suggest that by using a larger balloon and faster sampling, the sensor can be used to determine the fracture behavior of tongue‐crushable foods. [ABSTRACT FROM AUTHOR]

At the industrial scale, improvements to extra virgin olive oil (EVOO) processing are an important opportunity to increase both added‐value, and the product's organoleptic and chemical parameters. Concerning all the operations used during EVOO extraction, crushing and malaxation have an effect on the extraction efficiency and minor components composition extremely significant. In this context, a pilot industrial‐scale crusher is designed and developed that can control the amount of oxygen that is dosed directly into the produced olive paste. In this study, the effectiveness of this new technique, combined with different crushing speeds on EVOO quality, is evaluated. It is demonstrated that supplying oxygen to the paste enriches the volatile fraction, the mean increase is about 30% for the compounds associated to positive sensory notes, while the concentrations of the compounds associated to sensory defects are stationary on 5.2 mg kg−1. Practical Applications: This result is confirmed by a sensory analysis, notably an increase in fruity intensity. It is also shown that crushing speed affects the extraction of compounds such as biophenols, and increases the bitter taste. Increased bitterness is detected for samples crushed at 3500 rpm compared to those crushed at lower speed (mean 5.7±0.3 compared to 4.5±0.4). [ABSTRACT FROM AUTHOR]

This study aims to determine the effects of different pineapple maturity indices on the human taste and recognition threshold. Sensitivity levels of the subject's taste buds on four basic tastes, sweet, salty, sour, and bitter, were observed before, after they had ingested 50 g and up to 100 g of pineapple at maturity indices 3–7. Consumption of pineapple as low as 50 g had a significant (p <.02) influence on the sweet and bitter taste thresholds. The sensitivity of sweetness decreased (p <.02) after 50 g of pineapple intake at all maturation indices. However, the sensitivity of bitter taste was enhanced significantly after pineapple intake of 50 g at maturation indices 3 and 4. Pineapple intake at lower maturity indices had significantly influenced sweet and bitter taste thresholds that could impact food perception. Practical Applications: The manuscript brings a contribution to the field of food sensory evaluation and consumer studies. It reveals that while enjoying eating fresh pineapple, bromelain may affect taste receptors, influencing taste sensitivity, which could be a factor in determining food quality. The finding could be used as a guideline for exclusion criteria for the panelist selection or screening involved in the sensory evaluation. [ABSTRACT FROM AUTHOR]

Better management of head and neck squamous cell carcinomas (HNSCCs) requires a clearer understanding of tumor biology and disease risk. Bitter taste receptors (T2Rs) have been studied in several cancers, including thyroid, salivary, and GI, but their role in HNSCC has not been explored. We found that HNSCC patient samples and cell lines expressed functional T2Rs on both the cell and nuclear membranes. Bitter compounds, including bacterial metabolites, activated T2R-mediated nuclear Ca2+ responses leading to mitochondrial depolarization, caspase activation, and ultimately apoptosis. Buffering nuclear Ca2+ elevation blocked caspase activation. Furthermore, increased expression of T2Rs in HNSCCs from The Cancer Genome Atlas is associated with improved overall survival. This work suggests that T2Rs are potential biomarkers to predict outcomes and guide treatment selection, may be leveraged as therapeutic targets to stimulate tumor apoptosis, and may mediate tumor-microbiome crosstalk in HNSCC. [ABSTRACT FROM AUTHOR]

BACKGROUND The use of rapeseed protein for human nutrition is primarily limited by its strong bitterness, which is why the key bitter compound, kaempferol 3‐O‐(2‴‐O‐sinapoyl‐β‐sophoroside), is enzymatically degraded. RESULTS: Mass spectrometry analyses of an extract from an untreated rapeseed protein isolate gave three signals for m/z 815 [M‐H]. The predominant compound among the three compounds was confirmed as kaempferol‐3‐O‐(2‴‐O‐sinapoyl‐β‐sophoroside). Enzymatic hydrolysis of this key bitter compound was achieved using a sinapyl ester cleaving side activity of a ferulic acid esterase (FAE) from the basidiomycete Schizophyllum commune (ScoFAE). Recombinant ferulic acid esterases from Streptomyces werraensis (SwFAE) and from Pleurotus eryngii (PeFAE) possessed better cleavage activity towards methyl sinapate but did not hydrolyze the sinapyl ester linkage of the bitter kaempferol sophoroside. CONCLUSION: Kaempferol‐3‐O‐(2‴‐O‐sinapoyl‐β‐sophoroside) was successfully degraded by enzymatic treatment with ScoFAE, which may provide a means to move the status of rapeseed protein from feed additive to food ingredient. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Umami is an important element affecting food taste, and the development of umami peptides is a topic of interest in food‐flavoring research. The existing technology used for traditional screening of umami peptides is time‐consuming and labor‐intensive, making it difficult to meet the requirements of high‐throughput screening, which limits the rapid development of umami peptides. The difficulty in performing a standard measurement of umami intensity is another problem that restricts the development of umami peptides. The existing methods are not sensitive and specific, making it difficult to achieve a standard evaluation of umami taste. This review summarizes the umami receptors and umami peptides, focusing on the problems restricting the development of umami peptides, high‐throughput screening, and establishment of evaluation standards. The rapid screening of umami peptides was realized based on molecular docking technology and a machine learning method, and the standard evaluation of umami could be realized with a bionic taste sensor. The progress of rapid screening and evaluation methods significantly promotes the study of umami peptides and increases its application in the seasoning industry. [ABSTRACT FROM AUTHOR]

Saccharin is a commonly used artificial sweetener that exhibits both sweetening and sweet inhibition activities. The species‐dependent response towards saccharin and the interaction between saccharin and the sweet taste receptor T1R2/T1R3 remain elusive. In this study we used mismatched chimeras of T1R2 and T1R3 and calcium mobilization functional analysis to reveal a detailed species‐dependent response towards saccharin of human, squirrel monkey, and mouse sweet taste receptors. Our findings, combined with previous results by others, suggest multiple and complex interaction modes between saccharin and the sweet taste receptor, which are helpful guidelines for effective modulation of the sweet taste by sweetener/sweet inhibitors. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mushroom possesses desirable aroma, taste, texture, health‐promoting and disease‐preventing dietary components, making it an ideal ingredient, especially for animal‐based food substitution. Nevertheless, no study has replaced egg whites partially with mushrooms and investigated their sensory quality. This study aimed to investigate flavor impartment of mushroom on egg whites and the sensory quality of roasting and steaming egg whites replaced by white and crimini mushrooms at 0%, 10%, 20% and 30%, respectively, using a panel trained with aroma chemical references for 31 sensory attributes with 0–10 line scales. RESULTS: Roasted and steamed egg whites possessed major sensory attributes of sulfury and egg‐like aroma and flavor (intensities > 3). After mushroom topping was added, the dominant sensory attributes shifted to mushroom‐based flavor characteristics, including mushroom‐like, earthy, dark meat, roasted, hay, soybean, potato, woody, umami, bitter, astringent and firmness texture. Mushroom variety showed significant (P ≤ 0.05) impacts on egg white sensory quality, with crimini introducing more intense flavor. The higher the mushroom proportion with egg whites, the more intense was the flavor associated with mushroom. Mushroom could enhance egg‐like flavor in multiple dimensions, including aroma, taste and texture, according to partial least square regression. CONCLUSION: White and crimini mushrooms enriched roasted and steamed egg white sensory quality with introduction of characteristic sensory attributes from mushrooms. Mushroom variety and proportion with egg whites displayed significant impacts on egg white sensory properties. The study contributed to understanding the impact of mushrooms on egg white sensory profile and served as a guide in incorporating mushroom in product development. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Umami and sweet sensations provide animals with important dietary information for detecting and consuming nutrients, whereas bitter sensation helps animals avoid potentially toxic or harmful substances. Enormous progress has been made toward animal sweet/umami taste receptor (Tas1r) and bitter taste receptor (Tas2r). However, information about amphibians is mainly scarce. This study attempted to delineate the repertoire of Tas1r/Tas2r genes by searching for currently available genome sequences in 14 amphibian species. This study identified 16 Tas1r1, 9 Tas1r2, and 9 Tas1r3 genes to be intact and another 17 Tas1r genes to be pseudogenes or absent in the 14 amphibians. According to the functional prediction of Tas1r genes, two species have lost sweet sensation and seven species have lost both umami and sweet sensations. Anurans possessed a large number of intact Tas2rs, ranging from 39 to 178. In contrast, caecilians possessed a contractive bitter taste repertoire, ranging from 4 to 19. Phylogenetic and reconciling analysis revealed that the repertoire of amphibian Tas1rs and Tas2rs was shaped by massive gene duplications and losses. No correlation was found between feeding preferences and the evolution of Tas1rs in amphibians. However, the expansion of Tas2rs may help amphibians adapt to both aquatic and terrestrial habitats. Bitter detection may have played an important role in the evolutionary adaptation of vertebrates in the transition from water to land. [ABSTRACT FROM AUTHOR]

Bitter taste warns us against ingesting toxic chemicals but can also discourage consumption of healthful nutrients and prescribed medications. Thus, discovery of ingredients to reduce bitterness is an important research priority. The potential bitter‐taste‐blocking effect of sophorolipids has recently been reported. Sophorolipids are biosurfactant glycolipids normally synthesized via yeast fermentation. In the current experiments, the effect of sophorolipid on bitter taste was evaluated using both cultured human taste papillae (HBO) cells and in vivo sensory experiments with human tasters. Sophorolipids significantly reduced responses of HBO cells to a mixture of diverse bitter compounds. Human participants rated the bitterness of a mixture of diverse bitter compounds as less intensely bitter both after prerinsing with a sophorolipid solution and when sophorolipids were added to the mixture. Taken together, these results suggest that sophorolipids may reduce perceived bitterness in humans, at least in part by acting on peripheral mechanisms. Although further work is needed to confirm these findings and determine the exact mechanism(s) of action, thus far sophorolipids show promise as candidate ingredients to reduce bitterness. [ABSTRACT FROM AUTHOR]

BACKGROUND: Thaumatin II, a supersweet protein from the African plant katemfe (Thaumatococcus daniellii Benth.), shows promise as a zero‐calorie sweetener for use in the food and pharmaceutical industries and for improving the taste of fruit. RESULTS: We report on the stability of thaumatin in salted and pickled tomatoes, as well as on the effect of thaumatin on the taste quality of processed tomatoes. Fruit of tomato cv. Yalf, transformed with the thaumatin II gene were salted and pickled and then stored for 6 months. Western blot analysis showed relative thaumatin II stability at salting; its content in processed fruits was 62–83% of the initial level depending in the studied line. In pickled tomatoes, thaumatin II content was decreased by up to 25% of the initial amount. Both salted and pickled tomatoes had a sweet taste with a typical thaumatin aftertaste. Salted tomatoes were characterized as being sweeter than pickled tomatoes. The overall taste of pickled tomatoes was rated by panellists as significantly better compared to that of salted or non‐processed ones. CONCLUSION: In the present study, we have shown that tomatoes expressing supersweet protein thaumatin II can be used for processing under mild conditions, including salting and pickling. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pericarp of citrus in rutaceae is rich in flavonoids that may possess diverse biological activities. Some citrus flavonoids have been used as natural bitterness inhibitors; however, many citrus flavonoid analogues that possess merit taste amelioration functions have not been reported with respect to utilization in food industry. RESULTS: The effects of 12 citrus flavonoids on the inhibition of the bitter taste of naringin, quinine hydrochloride and stevioside were evaluated both by a sensory panel and electronic tongue analysis. Among the flavonoid compounds evaluated, both neohesperidin dihydrochalcone (NHDC) and neodiosmin were identified to show an excellent bitterness inhibition effect on all three bitterness vehicles tested. The results of the electronic tongue evaluation also showed that the addition of neodiosmin, NHDC or hesperidin dihydrochalcone‐7‐o‐glucoside (HDC‐7‐G) was able to reduce significantly the bitterness response value of quinine hydrochloride, which is consistent with the sensory panel evaluation. Structure–activity relationship analysis found that the 7‐linked neohesperidosyloxy group in the A‐ring of the citrus flavonoid skeleton has the best bitterness inhibition effect. In addition, a ternary mixture of NHDC, neodiosmin and naringin, and neodiosmin/β‐cyclodextrin was formulated and it demonstrated, for the first time in the flavor improvement of citrus fruit wine, an enhancement of sweetness and a reduction of bitter taste. CONCLUSION: Twelve citrus flavonoids were found to inhibit the bitter taste of naringin, quinine hydrochloride and stevioside. With respect to the structure–activity relationship analysis, it was found that the 7‐linked neohesperidosyloxy group in the A‐ring of the citrus flavonoid skeleton possessed the best bitterness inhibition effect. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Bats represent the largest dietary radiation in a single mammalian order, and have become an emerging model group for studying dietary evolution. Taste receptor genes have proven to be molecular signatures of dietary diversification in bats. For example, all 3 extant species of vampire bats have lost many bitter taste receptor genes (Tas2rs) in association with their dietary shift from insectivory to sanguivory. Indeed, only 8 full‐length Tas2rs were identified from the high‐quality genome of the common vampire bat (Desmodus rotundus). However, it is presently unknown whether these bitter receptors are functional, since the sense of taste is less important in vampire bats, which have an extremely narrow diet and rely on other senses for acquiring food. Here, we applied a molecular evolutionary analysis of Tas2rs in the common vampire bat compared with non‐vampire bats. Furthermore, we provided the first attempt to deorphanize all bitter receptors of the vampire bat using a cell‐based assay. We found that all Tas2r genes in the vampire bat have a level of selective pressure similar to that in non‐vampire bats, suggesting that this species must have retained some bitter taste functions. We demonstrated that 5 of the 8 bitter receptors in the vampire bat can be activated by some bitter compounds, and observed that the vampire bat generally can not detect naturally occurring bitter compounds examined in this study. Our study demonstrates functional retention of bitter taste in vampire bats as suggested by cell‐based functional assays, calling for an in‐depth study of extra‐oral functions of bitter taste receptors. [ABSTRACT FROM AUTHOR]

Bitter taste receptors (TAS2Rs) and their signaling elements are detected throughout the body, and bitter tastants induce a wide variety of biological responses in tissues and organs outside the mouth. However, the roles of TAS2Rs in these responses remain to be tested and established genetically. Here, we employed the CRISPR/Cas9 gene‐editing technique to delete three bitter taste receptors—Tas2r143/Tas2r135/Tas2r126 (i.e., Tas2r triple knockout [TKO]) in mice. The fidelity and effectiveness of the Tas2r deletions were validated genetically at DNA and messenger RNA levels and functionally based on the tasting of TAS2R135 and TAS2R126 agonists. Bitter tastants are known to relax airways completely. However, TAS2R135 or TAS2R126 agonists either failed to induce relaxation of pre‐contracted airways in wild‐type mice and Tas2r TKO mice or relaxed them dose‐dependently, but to the same extent in both types of mice. These results indicate that TAS2Rs are not required for bitter tastant‐induced bronchodilation. The Tas2r TKO mice also provide a valuable model to resolve whether TAS2Rs mediate bitter tastant‐induced responses in many other extraoral tissues. [ABSTRACT FROM AUTHOR]

Understanding the neural principles governing taste perception in species that bear economic importance or serve as research models for other sensory modalities constitutes a strategic goal. Such is the case of the honey bee (Apis mellifera), which is environmentally and socioeconomically important, given its crucial role as pollinator agent in agricultural landscapes and which has served as a traditional model for visual and olfactory neurosciences and for research on communication, navigation, and learning and memory. Here we review the current knowledge on honey bee gustatory receptors to provide an integrative view of peripheral taste detection in this insect, highlighting specificities and commonalities with other insect species. We describe behavioral and electrophysiological responses to several tastant categories and relate these responses, whenever possible, to known molecular receptor mechanisms. Overall, we adopted an evolutionary and comparative perspective to understand the neural principles of honey bee taste and define key questions that should be answered in future gustatory research centered on this insect. [ABSTRACT FROM AUTHOR]