Bitter Taste Research Articles

Effects of chronic unpredictable mild stress-induced depression on bitter taste receptor expression in mice

ObjectiveWith the rapid increase in the pace of life, people are facing increasing pressures of all kinds, and depression has gradually become a serious psychological disorder in human society, strongly affecting normal social and physiological activities. Depression can disrupt an individual's taste perception and potentially result in taste disorders by affecting and altering taste receptors. This disruption can consequently impact their food preferences and overall eating experiences. DesignIn this study, we used the chronic unpredictable mild stress (CUMS) method to establish a depression model in male C57BL/6 J mice and explored the changes in taste receptor expression in the lingual circumvallate papillae (CP) to elucidate the effects of depression on taste. After 6 weeks of CUMS, behavioral performance evaluations, such as forced swim, open field, and elevated plus maze tests, were conducted in depression model mice. A further two-bottle choice test was subsequently performed to determine the effect of depression on bitter taste, and the expression of bitter taste receptors in the lingual CP was detected via immunofluorescence staining. ResultsIn this study, we found for the first time that mice with CUMS-induced depression had decreased bitter taste sensitivity through a two-bottle choice test and demonstrated that the expression of T2r5, a receptor related to bitter taste perception, and the expression of secondary taste signaling proteins in the lingual CP were significantly decreased in mice exposed to CUMS, as determined via qRTPCR and immunofluorescence staining. ConclusionsOur study highlights how CUMS influences the perception of bitterness in the peripheral taste system, potentially elucidating stress-induced changes in eating habits.

Metabolite Profiling and Identification of Sweet/Bitter Taste Compounds in the Growth of Cyclocarya Paliurus Leaves Using Multiplatform Metabolomics.

Cyclocarya paliurus tea, also known as "sweet tea", an herbal tea with Cyclocarya paliurus leaves as raw material, is famous for its unique nutritional benefits and flavor. However, due to the unique "bittersweet" of Cyclocarya paliurus tea, it is still unable to fully satisfy consumers' high-quality taste experience and satisfaction. Therefore, this study aimed to explore metabolites in Cyclocarya paliurus leaves during their growth period, particularly composition and variation of sweet and bitter taste compounds, by combining multi-platform metabolomics analysis with an electronic tongue system and molecular docking simulation technology. The results indicated that there were significant differences in the contents of total phenols, flavonoids, polysaccharides, and saponins in C. paliurus leaves in different growing months. A total of 575 secondary metabolites were identified as potential active metabolites related to sweet/bitter taste using nontargeted metabolomics based on UHPLC-MS/MS analysis. Moreover, molecular docking technology was utilized to study interactions between the candidate metabolites and the sweet receptors T1R2/T1R3 and the bitter receptors T2R4/T2R14. Six key compounds with high sweetness and low bitterness were successfully identified by using computational simulation analysis, including cis-anethole, gluconic acid, beta-D-Sedoheptulose, asparagine, proline, and citrulline, which may serve as candidates for taste modification in Cyclocarya paliurus leaves. These findings provide a new perspective for understanding the sweet and bitter taste characteristics that contribute to the distinctive sensory quality of Cyclocarya paliurus leaves.

A patient report scale research to access the symptom burden in patients with IgA nephropathy

Patients diagnosed with IgA nephropathy (IgAN) commonly experience a substantial burden of symptoms encompassing both physical and psychological aspects. Presently, there's a dearth of standardized assessment tools to effectively gauge the extent of symptom burden in IgAN patients. Therefore, this study aims to devise an IgAN Symptom Assessment Tool that enables a comprehensive evaluation of patient symptom burden and their self-perceived severity. Employing a prospective observational design, this study conducted a survey among patients diagnosed with IgAN at a hospital in China. The research team formulated an IgAN Symptom Burden Assessment Scale and administered a questionnaire to gauge patient symptom burden. Severity assessment was conducted on a 5-point Likert scale, with higher scores indicating a more pronounced burden of symptoms. The finalized scale comprised 14 distinct symptom items, and the questionnaire survey garnered responses from 200 patients, achieving a 100% response rate. Statistical analysis unveiled that nearly all patients regarded these symptoms as prevalent and significantly impactful on their daily lives, resulting in a considerable burden. Notably, mild oliguria, moderate nasal congestion, bitter taste , throat discomfort, alongside severe manifestations such as muscle weakness, fatigue, and foamy urine, were frequently reported by patients. The findings underscore that a substantial proportion of IgAN patients grapple with a significant burden of symptoms, emphasizing the imperative for healthcare providers to prioritize symptom management and implement proactive measures to alleviate these challenges. This study presents an innovative tool tailored for evaluating symptom burden specifically in IgAN patients. Subsequent research should center on validating this tool within larger patient cohorts to optimize the efficacy of symptom management in this demographic.

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)-3β-O-malonyl-7β,25-dihydroxycucurbita-5,23-dien-19-al (2), 3-O-β-d-allopyranosyl-7β,25-dihydroxycucurbita-5,23(E)-dien-19-al (3), momordicine IV (5), and charantoside B (6) and three new compounds 3-O-β-d-3-ketoglucopyranosly-7β,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.

Anti-Schistosomal activity and ADMET properties of 1,2,5-oxadiazinane-containing compound synthesized by visible-light photoredox catalysis.

The incorporation of saturated nitrogen-containing heterocycle 1,2,5-oxadiazinane into small molecules represents a compelling avenue in drug discovery due to its unexplored behavior within biological systems and incomplete protocols for synthesis. In this study, we present 1,2,5-oxadiazinane, an innovative heterocyclic bioisostere of piperizin-2-one and novel chemotype of the anti-schistosomal drug praziquantel (PZQ), which has been the only clinical drug available for three decades. PZQ is associated with significant drawbacks, including poor solubility, a bitter taste, and low metabolic stability. Therefore, the discovery of a new class of anti-schistosomal agents is imperative. To address this challenge, we introduce a pioneering method for the synthesis of 1,2,5-oxadiazinane derivatives through the cycloaddition of nitrones with N,N,N',N'-tetraalkyldiaminomethane in the presence of an IrIII complex photosensitizer. This transformative reaction offers a streamlined route to various kinds of 1,2,5-oxadiazinanes that is characterized by mild reaction conditions and broad substrate scope. Mechanistic investigations suggest that the photoredox pathway underlies the [3 + 3] photocycloaddition process. Thus, based on bioisosteric replacement, we identified a remarkable molecule as a new chemotype of a potent anti-schistosomal compound that not only exhibits superior solubility, but also retains the potent biological activity inherent to PZQ.

Citizen science tools for engaged research: Waterquality monitoring in remote communities

Remote areas that lack conventional water-provisioning infrastructure often rely on rainwater harvesting, rivers, pans, reservoirs and borehole-extracted water to meet domestic water requirements. These water sources often have poor microbial quality and chemical composition, the quality of which is not routinely monitored. This study explored citizen science as a tool for Engaged Research and Responsible Research and Innovation, detailing the co-creation of a sustained community-based water quality monitoring program in collaboration with communities in villages in Amakhala Game Reserve (Eastern Cape, South Africa). Without access to other water sources, participants predominantly used rainwater for drinking and cooking (80%), while borehole water was mainly used for cleaning and gardening due to its salty or bitter taste. A hydrogen sulphide (H2S) water testing kit was used by the citizen scientists to monitor the water quality. The H2S kits were effective in estimating bacterial contamination, showing a proportional relationship with Colilert® test results conducted in a laboratory. The alignment observed between community-based monitoring results and those derived from scientist-led testing underscores the value of data produced through citizen science initiatives. Sustained participant engagement throughout this research reflected a sense of community empowerment through access to tools that inform their decision-making around water use and treatment as well as investment in the research, indicative of the perceived relevance of the research to community interests. This integration of transdisciplinary data sources holds promise for informing evidence-based decision-making processes, facilitating more effective and contextually informed water management strategies that value and integrate community perspectives alongside scientific insights.

How sugar types and fabrication methods affect palatability in paediatric-friendly oromucosal pullulan films of chlorpromazine hydrochloride

Ensuring children adhere to their prescribed medication can be challenging, particularly when a large number of medicines on the market consist of unpalatable drugs and difficult to swallow dosage forms. Sugar-based oromucosal films are easy to administer dosage forms across all age groups within the paediatric population, as they eliminate the need for swallowing or water intake and can contribute to enhancing palatability and medicine adherence. In the current study, electrospun and 3D printed oromucosal films of chlorpromazine hydrochloride (CHZ), a bitter drug, were developed based on pullulan, a natural polysaccharide, and an array of sweeteners. Their taste masking efficacy was assessed in vitro using an electronic tongue, showing a significant suppression of the bitter taste of CHZ in the presence of sucralose, sucrose and isomalt in the 3D-printed films. In vivo assessment further confirmed that the sugar-based 3D printed films are highly acceptable to volunteers. For the electrospun films, volunteers reported neutral responses for overall acceptability, likely due to their lack of familiarity with this type of formulation. Overall, with improved acceptability and further optimization for taste masking, sugar-based films could serve as a viable alternative to conventional solid oral dosage forms for administering drugs to children.

Raman Spectroscopic Analysis of Steviol Glycosides: Spectral Database and Quality Control Algorithms

Besides all sharing an extraordinary high (i.e., up to ~450 times) sweetening power as compared to sucrose and while presenting strong similarities in their molecular structures, molecules belonging to the family of diterpene glycosides (i.e., the secondary metabolites of Stevia rebaudiana) differ in specific structural details that strongly impact on their levels of sweetness and bitter aftertaste. Given the nutritional and pharmacological benefits of steviol secondary metabolites as natural dietetic and anti-diabetic remedies, extraction and purification of steviol glycosides from plant material are nowadays widely spread among many countries. However, an unpleasant bitter aftertaste, which is linked to a genetic variation in human bitter taste receptors, hampers the full exploitation of such benefits and calls for a prompt improvement in organoleptic property control of stevia products. A deeper understanding of the molecular structure of different steviol glycosides and the consequent development of promptly measurable criteria for the organoleptic performance of their mixtures will support processing optimization and control of taste profiles within desired yields. The present research aimed at establishing Raman spectroscopic algorithms for quantitative characterizations of raw stevia-based sweetener products. First, a series of twelve high-purity diterpene glycosides were analyzed by high spectrally resolved Raman spectroscopy and their spectra analyzed in order to establish a complete Raman library of molecular structures. Then, quantitative spectroscopic parameters were built up and applied to characterize the organoleptic property of five different commercially available samples including the recently developed Rebaudioside M isoform. Raman spectroscopy was confirmed as a versatile analytical technique that could be used for quantitative quality control tasks on the production line and for prompt in situ characterizations of purchased products.

Determination of specific and non-specific standardization parameters for ethanol extract of purple leaves (Graptophyllum pictum (L) Griff )

Purple leaves are a traditional medicine that is widely used by people in West Java, Maluku and Papua. Empirically, purple leaves are usually used to treat wounds, liver swelling, and treat gallstones. The aim of this research is to establish standardization of specific parameters (organoleptic and chemical content) and non-specific parameters (ash content, water content, drying loss, heavy metal contamination, yeast mold number (AKK), microbial contamination/Total Plate Number (ALT)) as well as antioxidant on purple leaf plants (Graptophyllum pictum (L) Griff). The results showed that the specific parameters of the organoleptic properties of the 96% ethanol extract of purple leaves ( Graptophyllum pictum (L) Griff ) namely black in color , shaped like paste, has a distinctive purple leaf odor and a bitter taste. The results of the phytochemical screening of 96% ethanol extract of cherry leaves contain alkaloids, flavonoids and tannins . However, the saponin test was negative for containing saponin. The non-specific parameters of 96% ethanol extract of cherry leaves are water content of 5.96 % , total ash content of 16.8570 %, drying loss of 17.26 %, heavy metals As and Cd were not detected in Pb of 0, 1236 mg/kg, microbial contamination (Alt) and yeast mold numbers (Akk) were not found in colonies. Based on standardization testing of non-specific parameters, purple leaf simplicia meets the simplicia quality standards

Comparison of oven drying and freeze drying methods for the production of fast melt films containing quetiapine fumarate

Background Quetiapine fumarate (QTP) is commonly prescribed for schizophrenic patient, typically available in tablet or oral suspension form, presenting challenges such as administration difficulties, fear of choking and distaste for its bitter taste. Fast melt films (FMF) offer an alternative dosage form with a simple development process, ease of administration and rapid drug absorption and action onset. Objective This study aims to prepare FMF with different formulations using solvent casting methods and to compare the effects of different drying methods, including oven drying and freeze drying, on the properties of the films. Methods Various formulations were created by manipulating polymer types (starch, hydroxypropyl methylcellulose (HPMC) and guar gum) at different concentrations, along with fixed concentrations of QTP and other excipients. Characterisation tests including surface morphology, weight, thickness, pH, tensile strength, elongation length, Young’s modulus, folding endurance and disintegration time were conducted. The optimal FMF formulation was identified and further evaluated for moisture and drug content, dissolution behaviour, accelerated stability, X-ray diffraction (XRD), and palatability. Results FMF containing 10 mg guar gum/film developed using oven drying emerged as the optimum choice, exhibiting desirable film appearance, ultra-thin thickness (0.453 ± 0.002 mm), appropriate pH for oral intake (pH 5.0), optimal moisture content of 11.810%, rapid disintegration (52.67 ± 1.53 seconds), high flexibility (folding endurance > 300 times) and lower Young’s modulus (1.308 ± 0.214). Conclusion Oven drying method has been proven to be favourable for developing FMF containing QTP, meeting all testing criteria and providing an alternative option for QTP prescription.

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.

Factors Influencing Elderly Consumers' Preferences for Edible Gels: Insights from Slovakia.

As dietary needs shift with the growing and aging population, there is a demand for food products that meet nutritional, safety, and tribological requirements while being cost-effective. Seniors must be given significant consideration in new product development. This study examines consumer preferences for arabinogalactan (AG) and beta-glucan (BG) hydrogels with vanilla and coffee-biscuit flavors, using consumer tests (N = 80) and an online survey (N = 852). It focuses on the gels' physical properties, such as texture and viscosity, and their impact on sensory perception. The use of two different gel-forming polysaccharides, each with a unique sensory profile, was observed to affect the sensory properties of the resulting gels and subsequently influence product acceptance. This study analyzed preferences across three age groups: young (18-39 years), middle-aged (40-59 years), and older adults (60+ years). The results showed that seniors preferred AG-based gels. Significant attributes such as the intensity of flavor and bitter taste influenced the overall liking of the gels. Texture also notably impacted preferences. The survey findings revealed statistically significant (p < 0.05) differences in preferences between older adults and younger age groups. Tailoring product development and marketing strategies based on age and sensory preferences could enhance consumer acceptance of edible gels.

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 carbon‑carbon 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.

An Integration of UPLC-Q-TOF-MS, GC-MS, Electronic Nose, Electronic Tongue, and Molecular Docking for the Study of the Chemical Properties and Flavor Profiles of Moringa oleifera Leaves

Moringa oleifera leaves (MOLs) have gained significant attention due to their nutritional and biological activity. Therefore, this study aimed to examine its flavor characteristics and underlying compositions. In this study, we used ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), gas chromatography-mass spectrometry (GC-MS), electronic nose, electronic tongue, and molecular docking to comprehensively investigate the chemical properties and flavor profiles of MOLs. UPLC-Q-TOF-MS and GC-MS were instrumental in identifying the 20 non-volatile and 19 volatile constituents of MOLs, respectively. The electronic nose and electronic tongue systems provided an objective evaluation of the sweet, bitter, and spicy attributes and flavor characteristics of MOLs. Concurrently, molecular docking was employed to elucidate the material basis of flavor profiles. It revealed that glucosinolates and flavonoids are probably the key components for the bitter taste of MOLs. The sweet taste may be attributed to glucosinolates and flavonoids. The spicy scent appears to be linked to the presence of glucosinolates and alkaloids. The integration of these techniques confers a thorough understanding of the chemical composition and sensory properties of MOLs. These findings have significant implications for innovative applications in the food industry as well as pharmaceuticals and agriculture sectors; furthermore, they contribute towards enhancing the perception of Moringa oleifera as a valuable natural resource.

Dry-ageing impacts on meat quality, oxidative stability, and release of free amino acids in striploins from dairy crossbred yearling and 2-year-old steers

This study determined the impacts of dry-ageing on meat quality, oxidative stability, and release of free amino acids (FAAs) in striploins from dairy-crossbred yearlings and 2-year-old steers (n = 12 each group) over 21 days of in-bag dry-ageing. Dry-ageing increased weight losses, with higher % drying rates in yearling meat during dry-ageing, likely due to the smaller loin size and lower intramuscular fat content (P < 0.05). Yearling meat showed greater (P < 0.05) decreases in moisture content, but both meats reached similar moisture levels by day 21. pH values increased with dry-ageing with variations at different ageing times. Dry-ageing reduced a*, b*, and chroma while increasing L* and hue angles on day 21 (P < 0.05), likely due to dehydration and lipid oxidation (higher TBARS, P < 0.05) after 14 days, especially in yearling meat. The decreased levels (P < 0.05) of some monounsaturated fatty acids and conjugated linoleic acid cis-9, trans-11 were likely linked with lipid oxidation. Total levels of FAAs and essential amino acids increased significantly, especially within the first 7 days, with distinct patterns between the two meats. Dry-aged yearling meat contained more FAAs associated with sweat taste (e.g., glutamine and glycine) and fewer FAAs associated with bitter taste (e.g., phenylalanine and tyrosine). Carnosine levels varied and significantly increased after 21 days. Dry-ageing demonstrated distinct effects on dehydration, lipid oxidation, and release of FAAs in meat from yearlings compared with 2-year-old steers, which can be tailored to develop high-quality beef products with unique flavours.

Determination of objective taste perception among Iranian medical sciences students during COVID‑19 pandemic in Yazd, Eastern Iran: a case-control pilot study

BackgroundTaste disorders in patients suffering from COVID-19 were popular. Some people even after recovery report residual effects of loss of smell and taste. This study aimed to investigate the taste Perception of Iranian Medical Sciences students during the COVID-19 pandemic.MethodsThe case-control study evaluated 50 Medical Sciences students with a history of COVID-19 infection, as confirmed by the Novel Coronavirus (2019-nCOV) CFX96™ Real-Time PCR Detection System. The other participants consisted of 50 volunteer students with COVID-19 negative. The taste perception was measured with 4 different concentrations of the basic tastes. The stimuli were applied to the protruded tongue. Subjects were asked to identify the researcher when they felt the taste. Data are expressed as frequency distribution and analyzed with the Chi-Square test (P < 0.05).ResultsIn this survey, 54% of participants were male and 46% were female, the mean age of participants was 22.96 ± 5 years. The results showed a significant difference in the sweet and bitter taste perception score according to the history of dietary supplement use. The bitter taste perception score declared a considerable difference since COVID-19 infection. There was no significant difference between the taste perception in the two studied groups for all 4 basic tastes according to gender, COVID-19 infection status, history of taste and smell disorders, and the elapsed time since COVID-19 infection.ConclusionOur findings could provide important insights into taste perception. The history of dietary supplementation may influence how sweetness and saltiness are perceived. There was a noticeable difference in bitter taste perception depending on the time that had elapsed since the most recent COVID-19 infection.

Enzymatic hydrolysis pretreatment combined with glycosylation for soybean protein isolate applying in dual-protein yogurt

This research investigated the viability of replacing milk protein with glycosylated soybean protein isolate (SPI) treated with different enzymatic hydrolysis times (0, 10, 20, 30, 40, and 50 min) in yogurt. The results showed that enzymatic hydrolysis pretreatment combined with glycosylation for SPI exhibited elevated grafting and solubility. Additionally, the high solubility of SPI (94.77 %) at 40 min facilitates the preparation of dual-protein yogurt (DPY). Compared to ESPI0-G, DPY that incorporates ESPI40-G through partial substitution of milk protein is capable of forming a denser and more stable gel matrix. Especially, the syneresis of DPY40 was reduced by 7.61 % compared to DPY0, which more closely approximates the texture properties of traditional yogurt. Meanwhile, glycosylated SPI treated with enzymatic hydrolysis can effectively degrade the beany flavor and slightly bitter taste in DPY. This study could provide a solid theoretical basis for the broader application and industrialization of plant-based yogurt.

The Anaesthetic Efficacy of Tetracaine and Oxymetazoline Compared With Co-Phenylcaine in Healthy Individuals.

Nasal anaesthetic-decongestant sprays are commonly used prior to nasal instrumentation, such as flexible and rigid nasal endoscopy. Co-phenylcaine (lignocaine 5%, phenylephrine 0.5%, ENT Technologies Pty Ltd., Melbourne, VIC, Australia) is a combination spray commonly used for this purpose. However, lignocaine is less potent than other local anaesthetics, and both active constituents of Co-phenylcaine have a bitter taste. It was hypothesised that a combination spray containing tetracaine and oxymetazoline would both offer more potent topical anaesthesia and have a better taste. Four anaesthetic-decongestant nasal sprays were tested in 10 healthy participants (Co-phenylcaine, and tetracaine 0.5%, 1% and 2% with oxymetazoline 0.05%). Sensory thresholds were sequentially measured at the head of the inferior turbinate using Semmes-Weinstein monofilaments over the following hour. Participants also rated taste on a Likert-style scale, and reported whether they experienced subjective numbness of the maxillary teeth. A median peak sensory threshold of 60 g (the maximum tested) was observed with Co-phenylcaine, but this threshold was exceeded by all the tetracaine-based sprays. Tetracaine 2% with oxymetazoline 0.05% had a significantly more rapid onset than Co-phenylcaine (4 min vs. 6 min, p < 0.05) and a longer duration of action. Eight participants reported dental numbness after administration of tetracaine 2% with oxymetazoline 0.05%, but only one participant after Co-phenylcaine. Tetracaine-based sprays were generally perceived to taste less unpleasant than Co-phenylcaine. Tetracaine 2% with oxymetazoline 0.05% is a more potent and rapidly acting anaesthetic-decongestant spray than Co-phenylcaine, with a longer duration of action.

EFFECT OF SELECTED NATURAL EXTRACTS ON ANTIOXIDANT PROPERTIES AND SENSORY QUALITY OF VARIOUS CEREAL PRODUCTS

The aim of this study was to observe antioxidant properties as well as possible changes in sensory quality of selected bakery products after their enrichment with chosen natural extracts. Four types of natural extracts in mixture with wheat flour were used in various amounts for preparation of selected bakery products (wheat bread, sweet biscuits, salty crackers, and muffins). Specifically: turmeric (Curcuma longa, L.) rhizome extract (curcumin), quercetin dihydrate extracted from the pods of Sophora japonica, L., and extracts from medicinal fungus Shiitake (Lentinula edodes) and Maitake (Grifola frondosa) were used as additions. Antioxidant properties in total antioxidant activity (TAA; using DPPH radical scavenging assay), total polyphenols content and total phenolic acids content were examined, as well as the effect of selected natural extracts on the sensory properties of bakery products (intensity of certain characteristics and overall preference). The results of antioxidant properties varied according to the used extract and its amount. Compared with control products, the TAA was significantly higher in all enriched products. While the total polyphenol content was the highest in the bread and biscuits with quercetin (20.623 mg and 18.117 mg GAE.g-1, respectively), the total phenolic acids content was the highest in those with curcumin (8.846 mg and 3.286 mg CAE.g-1, respectively). The intensity of other smell and taste of enriched bakery products influenced considerably overall acceptance, e.g. the products with quercetin associated with bitter taste were evaluated as unfavourable. On the other hand, the breads and crackers with Shiitake extract with indistinct antioxidant properties were evaluated the best, followed with curcumin and Maitake extract. Considering our overall results, we can recommend chosen non-bakery raw materials for a production of new, innovative designed cereal-based products.

Genomic study of taste perception genes in African Americans reveals SNPs linked to Alzheimer’s disease

While previous research has shown the potential links between taste perception pathways and brain-related conditions, the area involving Alzheimer’s disease remains incompletely understood. Taste perception involves neurotransmitter signaling, including serotonin, glutamate, and dopamine. Disruptions in these pathways are implicated in neurodegenerative diseases. The integration of olfactory and taste signals in flavor perception may impact brain health, evident in olfactory dysfunction as an early symptom in neurodegenerative conditions. Shared immune response and inflammatory pathways may contribute to the association between altered taste perception and conditions like neurodegeneration, present in Alzheimer’s disease. This study consists of an exploration of expression-quantitative trait loci (eQTL), utilizing whole-blood transcriptome profiles, of 28 taste perception genes, from a combined cohort of 475 African American subjects. This comprehensive dataset was subsequently intersected with single-nucleotide polymorphisms (SNPs) identified in Genome-Wide Association Studies (GWAS) of Alzheimer’s Disease (AD). Finally, the investigation delved into assessing the association between eQTLs reported in GWAS of AD and the profiles of 741 proteins from the Olink Neurological Panel. The eQTL analysis unveiled 3,547 statistically significant SNP-Gene associations, involving 412 distinct SNPs that spanned all 28 taste genes. In 17 GWAS studies encompassing various traits, a total of 14 SNPs associated with 12 genes were identified, with three SNPs consistently linked to Alzheimer’s disease across four GWAS studies. All three SNPs demonstrated significant associations with the down-regulation of TAS2R41, and two of them were additionally associated with the down-regulation of TAS2R60. In the subsequent pQTL analysis, two of the SNPs linked to TAS2R41 and TAS2R60 genes (rs117771145 and rs10228407) were correlated with the upregulation of two proteins, namely EPHB6 and ADGRB3. Our investigation introduces a new perspective to the understanding of Alzheimer's disease, emphasizing the significance of bitter taste receptor genes in its pathogenesis. These discoveries set the stage for subsequent research to delve into these receptors as promising avenues for both intervention and diagnosis. Nevertheless, the translation of these genetic insights into clinical practice requires a more profound understanding of the implicated pathways and their pertinence to the disease's progression across diverse populations.