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

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

Polysaccharide Conjugates' contribution to mellow and thick taste of Pu-erh ripe tea, besides Theabrownin.

Mellow and thick taste (MTT) is considered to be a typical taste characteristic of high-quality Pu-erh ripe tea. However, the role of polysaccharide conjugates remains unclear. In this study, the infusion of different grades of Pu-erh ripe tea was isolated to fractions by sensory-guided ultrafiltration technology and the key taste substances of MTT in Pu-erh ripe tea were identified and confirmed in the sensory reconstruction experiment. Further separation, purification and structural identification of the polysaccharide conjugates were carried out. Involving in aggregation morphology, the ultrafiltration fraction exhibited obvious MTT than other fractions. The main MTT compound (PRTPS-5), mainly composed of the rhamnose, galactose, arabinose and mannose, had a molecular weight of 22.93 kDa. The main chain of PRTPS-5 comprised α-L-Araf-(1→, →2,4)-α-L-Rhap-(1→, →2)-α-L-Rhap-(1→, α-D-Galp-(1→, →4)-α-D-GalpA-6-OMe-(1→, →4)-α-D-Manp-(1→, →3,6)-ß-D-Galp-(1 â†’ and →5)-α-L-Araf-(1 â†’ and contained multiple pectic characteristic peaks. This result had scientific guiding significance for the quality enhancement of Pu-erh ripe tea.

Colour/shape-taste correspondences across three languages in ChatGPT.

Crossmodal correspondences, the tendency for a sensory feature / attribute in one sensory modality (either physically present or merely imagined), to be associated with a sensory feature in another sensory modality, have been studied extensively, revealing consistent patterns, such as sweet tastes being associated with pink colours and round shapes across languages. The present research explores whether such correspondences are captured by ChatGPT, a large language model developed by OpenAI. Across twelve studies, this research investigates colour/shapes-taste crossmodal correspondences in ChatGPT-3.5 and -4o, focusing on associations between shapes/colours and the five basic tastes across three languages (English, Japanese, and Spanish). Studies 1A-F examined taste-shape associations, using prompts in three languages to assess ChatGPT's association of round and angular shapes with the five basic tastes. The results indicated significant, consistent, associations between shape and taste, with, for example, round shapes strongly associated with sweet/umami tastes and angular shapes with bitter/salty/sour tastes. The magnitude of shape-taste matching appears to be greater in ChatGPT-4o than in ChatGPT-3.5, and ChatGPT prompted in English and Spanish than ChatGPT prompted in Japanese. Studies 2A-F focused on colour-taste correspondences, using ChatGPT to assess associations between eleven colours and the five basic tastes. The results indicated that ChatGPT-4o, but not ChatGPT-3.5, generally replicates the patterns of colour-taste correspondences that have previously been observed in human participants. Specifically, ChatGPT-4o associates sweet tastes with pink, sour with yellow, salty with white/blue, bitter with black, and umami with red across languages. However, the magnitude/similarity of shape/colour-taste matching observed in ChatGPT-4o appears to be more pronounced (i.e., having little variance, large mean difference), which does not adequately reflect the subtle nuances typically seen in human shape/colour-taste correspondences. These findings suggest that ChatGPT captures colour/shapes-taste correspondences, with language- and GPT version-specific variations, albeit with some differences when compared to previous studies involving human participants. These findings contribute valuable knowledge to the field of crossmodal correspondences, explore the possibility of generative AI that resembles human perceptual systems and cognition across languages, and provide insight into the development and evolution of generative AI systems that capture human crossmodal correspondences.

Spatial and temporal dynamics of microbes and genes in drinking water reservoirs: Distribution and potential for taste and odor generation.

Numerous reservoirs encounter challenges related to taste and odor issues, often attributed to odorous compounds such as geosmin (GSM) and 2-methylisoborneol (2-MIB). In this study, two large reservoirs located in northern and southern China were investigated. The Jinpen (JP) reservoir had 45.99 % Actinomycetes and 14.82 % Cyanobacteria, while the Xikeng (XK) reservoir contained 37.55 % Actinomycetes and 48.27 % Cyanobacteria. Most of the 2-MIB produced in surface layers of the two reservoirs in summer originated from Cyanobacteria, most of the 2-MIB produced in winter and in the bottom water originated from Actinomycetes. Mic gene abundance in the XK reservoir reached 5.42 × 104 copies/L in winter. The abundance of GSM synthase was notably high in the bottom layer and sediment of both reservoirs, while 2-MIB synthase was abundant in the surface layer of the XK reservoir, echoing the patterns observed in mic gene abundance. The abundance of odor-producing enzymes in the two reservoirs was inhibited by total nitrogen, temperature significantly influenced Actinomycetes abundance in the JP reservoir, whereas dissolved oxygen had a greater impact in the XK reservoir. Overall, this study elucidates the molecular mechanisms underlying odor compounding, providing essential guidance for water quality management strategies and the improvement of urban water reservoir quality.

Metabolomics and electronic-tongue analysis reveal differences in color and taste quality of large-leaf yellow tea under different roasting methods.

Roasting is a key process in the production of large-leaf yellow tea (LYT). In this study, we synthesized metabolomics and electronic-tongue analysis to compare the quality of charcoal-roasted, electric-roasted and drum-roasted LYT. Charcoal-roasted LYT had the highest yellowness and redness, drum-roasted LYT had a more prominent umami and brightness, and electric roasting reduced astringency. A total of 48 metabolites were identified by metabolomics. Among these, leucocyanidin, kaempferol, luteolin-7-lactate, and apigenin-7-O-neohesperidoside might affect the brightness and yellowness. Theanine, aspartic acid, and glutamic acid contents significantly and positively correlated with umami levels, and the high retention of flavonoid glycosides and catechins in drum-roasted LYT contributed to its astringency. These findings elucidate the contribution of the roasting method to the quality of LYT and provide a theoretical basis for LYT production.

Identification of Two New Taste-Active Compounds in Oak Wood: Structural Elucidation of Potential ß-Methyl-γ-octalactone Precursors and Quantification in Spirits.

Barrel aging is a crucial stage that influences the taste of wines and spirits, particularly increasing their sweetness and bitterness. This increase is caused by nonvolatile compounds released from oak wood. To search for such molecules, we performed a taste-guided inductive fractionation protocol using several analytical techniques. By using HRMS and NMR, two new galloylated derivatives were elucidated. Their enzymatic hydrolysis revealed the formation of ß-methyl-γ-octalactone, indicating that they are potential precursors. The taste properties of these isomers revealed a sweet and bitter taste for P-WL-1 and P-WL-2, respectively. An LC-HRMS quantification method was performed to evaluate the influence of aging parameters such as botanical origin and toasting process on their concentrations. Several spirits were also analyzed to confirm their presence in this matrix. These results improve the understanding of the molecular markers responsible for the taste of beverages.

Overlooked Role of Fungi in Drinking Water Taste and Odor Issues.

Taste and odor (T&O) are among the most frequently encountered aesthetic issues in drinking water. While fungi have been reported to produce offensive odors, their contribution to T&O in drinking water remains understudied and often overlooked. In this study, the profiles of fungal community and odorants produced by 10 native fungal isolates were investigated in 36 samples collected from two drinking water treatment plants and a premise plumbing system. A total of 17 odorants were identified with Penicillium, Aspergillus, Paecilomyces, and Alternaria genera exhibiting the highest odorant yields. Significant concentrations of musty/earthy compounds were produced by these fungal isolates, such as 2-methylisoborneol (2-MIB) (26-256 ng/L), geosmin (10-13 ng/L), and 2-isobutyl-3-methoxy-pyrazine (IBMP) (3-13 ng/L). The high odor activity value of the odorants primarily occurred within 4 d, while toxicity continued to increase during the 8 d incubation. UV treatment in premise plumbing significantly (p < 0.05) reduced the gene read counts of Ascomycota phylum, Aspergillus spp., Fusarium spp., Rhizopus spp., and Trichoderma spp., by 2.3-4.0 times. These findings underscore the previously underestimated role of fungi in contributing to T&O issues in drinking water and corresponding risks to consumers and indicate UV as a promising strategy for fungal control in drinking water.

Taste disturbance following cochlear implantation: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis aimed to estimate the rate of taste disturbance following cochlear implantation. METHODS: The review was designed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included studies psychophysically measured taste. DerSimonian and Laird random-effects models were used. An overall mean from studies reporting a single mean of taste strip performance was calculated using inverse variance method for pooling. RESULTS: Of 380 studies identified, 9 were included across which 55 cases of postoperative taste disturbance were reported in 498 patients. Taste was tested at variable timepoints, from <1 week to ≥6 months postoperatively. The overall rate of postoperative taste disturbance was 13.5% (95% CI, 7.6-20.7%) with high heterogeneity between studies (I2 = 62%). DISCUSSION: 13.5% might indicate a higher prevalence of taste disturbance following cochlear implantation compared to the general population. However, the confidence we can assign to our calculated rate is limited by significant heterogeneity and potential publication bias. Studies reporting mean taste strip scores generally found reduced taste function on the side of the tongue ipsilateral to implantation, but this reduction wasn't statistically significant. CONCLUSION: Further research, employing more robust and standardised methodologies, is necessary to accurately ascertain the rate and nature of taste disturbance following cochlear implantation.

A comprehensive review of plant-derived salt substitutes: Classification, mechanism, and application.

The diseases caused by excessive sodium intake derived from NaCl consumption have attracted widespread attention worldwide, and many researchers are committed to finding suitable ways to reduce sodium intake during the dietary process. Salt substitute is considered an effective way to reduce sodium intake by replacing all/part of NaCl in food without reducing the saltiness while minimizing the impact on the taste and acceptability of the food. Plant-derived natural ingredients are generally considered safe and reliable, and extensive research has shown that certain plant extracts or specific components are effective salt substitutes, which can also give food additional health benefits. However, these plant-derived salt substitutes (PSS) have not been systematically recognized by the public and have not been well adopted in the food industry. Therefore, a comprehensive review of PSS, including its material basis, flavor characteristics, and taste mechanism is helpful for a deeper understanding of PSS, accelerating its research and development, and promoting its application.

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

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

Perceived Taste and Olfactory Dysfunctions and Subsequent Stroke Risk.

Background: Taste and olfactory dysfunction are commonly associated with neurodegenerative diseases and cardiovascular risk factors, but their specific associations with stroke risk remain uncertain. Objectives: The purpose of this paper was to explore whether perceived taste and olfactory dysfunctions were associated with stroke risk. Methods: Included were 85,656 participants (mean age 51.0 ± 15.3 years) of the Kailuan study. Perceived olfactory and taste dysfunctions were assessed via a questionnaire at baseline (in 2014-2016). Incident stroke cases were confirmed by review of medical records. Cox proportional hazards models were used to investigate associations of perceived olfactory and taste dysfunctions with stroke risk, and mediation analysis was used to estimate the mediating effect of chronic disease statuses. Results: We documented 2,198 incident stroke cases during a mean of 5.6 years of follow-up. Perceived taste dysfunction was associated with a doubled risk of developing total stroke (adjusted HR: 2.03; 95% CI: 1.36-3.04; P < 0.001) even with adjustment of lifestyle factors, biomarkers (ie, blood lipids, blood glucose, blood pressure, and uric acid), and other potential confounders. However, perceived olfactory dysfunction (adjusted HR: 1.22; 95% CI: 0.79-1.90; P = 0.34) was not significantly associated with a high risk of total stroke. Similar results of both perceived taste and olfactory dysfunctions were observed for ischemic stroke. Presence of chronic diseases, including hypertension, diabetes, chronic kidney disease, and overweight/obesity, mediated 4% to 5% of the association of perceived taste dysfunction with both total stroke and ischemic stroke. Conclusions: In this large cohort study, perceived taste dysfunction was associated with a high risk of developing stroke.

Effects of Fermentation with Eurotium cristatum on Sensory Properties and Flavor Compounds of Mulberry Leaf Tea.

Mulberry leaf tea (MT) is a popular Chinese food with nutrition and medicinal functions. Solid-state fermentation with Eurotium cristatum of MT (FMT) can improve their quality. Differences in chromaticity, taste properties, and flavor characteristics were analyzed to evaluate the improvements of the sensory quality of FMT. After fermentation, the color of the tea infusion changed. The E-tongue evaluation results showed a significant decrease in unpleasant taste properties such as sourness, bitterness, astringency, and aftertaste-bitterness, while umami and saltiness taste properties were enhanced post-fermentation. Aroma-active compounds in MT and FMT were identified and characterized. A total of 25 key aroma-active compounds were screened in MT, and 2-pentylfuran showed the highest relative odor activity value (ROAV). A total of 26 key aroma-active compounds were identified in FMT, and the newly formed compound 1-octen-3-one showed the highest ROAV, which contributed to FMT's unique mushroom, herbal, and earthy flavor attributes. 1-octen-3-one, (E)-2-nonenal, trimethyl-pyrazine, 2-pentylfuran, and heptanal were screened as the potential markers that contributed to flavor differences between MT and FMT. E. cristatum fermentation significantly altered the sensory properties and flavor compounds of MT. This study provides valuable insights into the sensory qualities of MT and FMT, offering a theoretical basis for the development of FMT products.

Physicochemical and Sensory Properties and Antioxidant Activity of Xylitol Candies Containing Yuja (Citrus junos) Peels or Pulp.

Xylitol candies offer numerous health benefits such as preventing cavities and obesity. However, a preference for them tends to be low due to their distinctive flavor. In this study, we developed xylitol candies containing mature yuja peel (MYP-C), immature yuja peel (IYP-C), and yuja pulp (YP-C). To determine the optimal yuja added to xylitol candy, we compared and analyzed its physicochemical properties, sensory characteristics, and antioxidant activities. IYP-C and MYP-C significantly increased the naringin and hesperidin contents compared to the control and the YP-C. In particular, the IYP-C exhibited the highest content of flavonoids and polyphenols, which contributed to enhancing antioxidant activity such as ferric reducing antioxidant power (FRAP), 1,1 diphenyl-2-picrylhydrazyl (DPPH), and 2,2'-azino-di-2 ethyl-benzothiazoline sulfonate (ABTS+) radical scavenging activities. The IYP-C had the highest crude ash content. The L*, a*, and b* values of MYP-C and IYP-C showed dark red and yellow colors compared to the CON and YP-C groups. The sensory analysis conducted using electronic tongue equipment revealed that IYP-C exhibited high levels of umami, sweetness, and bitterness, while YP-C showed the highest intensity of sourness. In conclusion, these results suggest that IYP-C rather than MYP-C and YP-C provide xylitol candy with good qualities in terms of antioxidant activities and physicochemical characteristics.

Taste Sensor Assessment of Bitterness in Medicines: Overview and Recent Topics.

In recent decades, taste sensors have been increasingly utilized to assess the taste of oral medicines, particularly focusing on bitterness, a major obstacle to patient acceptance and adherence. This objective and safe method holds promise for enhancing the development of patient-friendly medicines in pharmaceutical companies. This review article introduces its application in measuring the intensity of bitterness in medicine, confirming the achievement of taste masking, distinguishing taste differences between branded and generic medicines, and identifying substances to suppress bitterness in target medicines. Another application of the sensor is to predict a significant increase in bitterness when medicine is taken with certain foods/beverages or concomitant medication. Additionally, to verify the sensor's predictability, a significant correlation has been demonstrated between the output of a bitter-sensitive sensor designed for drug bitterness (BT0) and the bitterness responses of the human taste receptor hT2R14 from BitterDB (huji.ac.il). As a recent advancement, a novel taste sensor equipped with lipid/polymer membranes modified by 3-Br-2,6-dihydroxybenzoic acid (2,6-DHBA), based on the concept of allostery, is introduced. This sensor successfully predicts the bitterness of non-charged pharmaceuticals with xanthine skeletons, such as caffeine or related compounds. Finally, the future prospects of taste sensors are discussed.

Machine learning predictive modeling of the persistence of post-Covid19 disorders: Loss of smell and taste as case studies.

The worldwide health crisis triggered by the novel coronavirus (COVID-19) epidemic has resulted in an extensive variety of symptoms in people who have been infected, the most prevalent disorders of which are loss of smell and taste senses. In some patients, these disorders might occasionally last for several months and can strongly affect patients' quality of life. The COVID-19-related loss of taste and smell does not presently have a particular therapy. However, with the help of an early prediction of these disorders, healthcare providers can direct the patients to control these symptoms and prevent complications by following special procedures. The purpose of this research is to develop a machine learning (ML) model that can predict the occurrence and persistence of post-COVID-19-related loss of smell and taste abnormalities. In this study, we used our dataset to describe the symptoms, functioning, and disability of 413 verified COVID-19 patients. In order to prepare accurate classification models, we combined several ML algorithms, including logistic regression, k-nearest neighbors, support vector machine, random forest, extreme gradient boosting (XGBoost), and light gradient boosting machine (LightGBM). The accuracy of the loss of taste model was 91.5 % with an area-under-cure (AUC) of 0.94, and the accuracy of the loss of smell model was 95 % with an AUC of 0.97. Our proposed modelling framework can be utilized by hospitals experts to assess these post-COVID-19 disorders in the early stages, which supports the development of treatment strategies.

Taste Disorders After Middle Ear Surgery: Chorda Tympani Nerve Injury and Quality of Life.

OBJECTIVE: To evaluate taste disorders after middle ear surgery, their modifying factors especially chorda tympani nerve injury or underlying otologic disease. We investigated consequences of taste disorders on quality of life. STUDY DESIGN: Prospective cohort study. SETTING: Monocentric study in tertiary care center. METHODS: A total of 214 patients who underwent middle ear surgery were included. Data regarding taste disorders were collected by questionnaires over a 1-year follow-up period. RESULTS: Taste disorders were reported in 42.7% at 10 days, in 23.3% at 4 months, and in 9.2% 1 year postoperatively. When the chorda tympani nerve was initially healthy, taste disorders were more frequent after its transection throughout the follow-up period. When it was involved in a cholesteatoma or inflammatory process, postoperative taste disorders were more frequent after nerve stretching. Postoperative discomfort in daily life was rated on the Likert scale at 3.5 out of 10. Dietary modifications were reported by 25.8% of patients, and mood alterations by 15% of patients. CONCLUSION: Taste disorders are frequent after middle ear surgery although they mostly improve in the first months. When the CTN is healthy, cutting it leads to more taste disorders than stretching it, thus advocating its preservation to prevent these symptoms. However, in cases of pathological CTN, cutting this nerve, which is sometimes necessary to control the disease, is less likely to cause taste disorders than stretching it. These taste disorders are a source of discomfort and may present risks of dietary modifications and emotional impact.

Umami taste receptor suppresses cancer cachexia by regulating skeletal muscle atrophy in vivo and in vitro.

BACKGROUND/OBJECTIVES: The umami taste receptor (TAS1R1/TAS1R3) is endogenously expressed in skeletal muscle and is involved in myogenesis; however, there is a lack of evidence about whether the expression of the umami taste receptor is involved in muscular diseases. This study aimed to elucidate the effects of the umami taste receptor and its mechanism on muscle wasting in cancer cachexia using in vivo and in vitro models. MATERIALS/METHODS: The Lewis lung carcinoma-induced cancer cachexia model was used in vivo and in vitro, and the expressions of umami taste receptor and muscle atrophy-related markers, muscle atrophy F-box protein, and muscle RING-finger protein-1 were analyzed. RESULTS: Results showed that TAS1R1 was significantly downregulated in vivo and in vitro under the muscle wasting condition. Moreover, overexpression of TAS1R1 in vitro in the human primary cell model protected the cells from muscle atrophy, and knockdown of TAS1R1 using siRNA exacerbated muscle atrophy. CONCLUSION: Taken together, the umami taste receptor exerts protective effects on muscle-wasting conditions by restoring dysregulated muscle atrophy in cancer cachexia. In conclusion, this result provided evidence that the umami taste receptor exerts a therapeutic anti-cancer cachexia effect by restoring muscle atrophy.

Untargeted metabolomics analyses to identify a new sweet compound released during post-fermentation maceration of wine.

The sensory quality of a wine is mainly based on its aroma and flavor. Sweetness contributes in the gustatory balance of red wines. The investigation of compounds involved in this flavor was based on empirical observations, such as the increase in wine sweetness during yeast autolysis, concomitant to post-fermentation maceration in red winemaking. An untargeted metabolomics approach using UHPLC-HRMS has been developed to discover a new sweet molecule released during this stage. Among several markers highlighted, one compound was selected to be isolated by various separative techniques. It was unambiguously identified by NMR as N6-succinyladenosine and is reported for the first time in wine at an average concentration of 3.16 mg/L in 85 red wines. Furthermore, sensory analysis has highlighted its sweetness. In addition to discovering a new sweet compound in wine, this study proposes new tools for studying taste-active compounds in natural matrices.