Flavor Perception Research Articles

Characterization of Metallic Off-Flavors in Drinking Water: Health, Consumption, and Sensory Perception.

Characterization of taste- and flavor-producing metals, namely iron and copper, in drinking water is a multifaceted subject. Both metals are essential nutrients, can be toxic, and are known to produce unpleasant tastes and flavor sensations in drinking water. Ingestion of trace metal contaminants through drinking water is a probable source of human exposure. Biochemical mechanisms of metallic flavor perception have been previously described; however, less is known about how variations in salivary constituents might impact individuals' sensitivities to metallic flavors and beverage consumption behaviors. This research presents findings from in vitro experiments, using artificial human saliva, to better understand the role of salivary lipids and proteins on metallic flavor production as measured by biomarkers of metal-induced oxidative stress. The results indicate that metal-induced lipid oxidation, as measured by thiobarbituric acid reactive substances (TBARS), is dominated by salivary proteins, is slightly inhibited in the presence of salivary nitrite, and is detectable by the TBARS method at and above respective concentrations of 9 µM (0.5 mg/L) and 90 µM (5 mg/L), which are both above the aesthetic standards for iron (0.3 mg/L) and copper (1.0 mg/L) in drinking water. Preliminary study with human subjects indicated that reduction in metallic flavor sensitivity, as measured by the best estimate flavor threshold for ferrous iron among 33 healthy adults aged 19-84 years old (22 females), corresponded with reduced drinking water consumption and increased caloric beverage intake among older subjects (>60 years), as determined by a validated self-reported beverage intake questionnaire. These findings provide insights for further research to examine how salivary constituents can impact humans' sensory abilities in detecting metallic off-flavors in water, and how reduced metallic flavor sensitivity may influence beverage choices and drinking water consumption.

Trigeminal Sensations to enhance and enrich flavor perception - Sensory Approaches

Trigeminal Sensations to enhance and enrich flavor perception - Sensory Approaches

A Cross-Sectional Analysis of Food Perceptions, Food Preferences, Diet Quality, and Health in a Food Desert Campus.

The sensory properties of foods guide food choices and intake, importantly determining nutritional and health status. In communities that have inconsistent access to nutritious foods, such as food deserts, food taste perceptions and preferences have yet to be explored. The purpose of this study was to examine how taster status (supertaster vs. non-taster) and food security status (high or marginal vs. low or very low) influences food taste intensities, food preferences and perceptions, and diet quality in a cohort of students from a food desert campus in the Central Valley of California. Moreover, the complex relationship of socioeconomic status, race/ethnicity, and sex on cardiometabolic and cognitive health warrants further examination. Two hundred fifty participants (aged 18-24 years) living in a food desert campus were recruited in 2018 for this cross-sectional study where participants underwent taste tests on selected fruits, vegetables, and nuts, and clinical tests (anthropometrics, blood glucose, blood pressure, and endothelial function), cognitive function tests (memory and attention), diet quality assessment (Healthy Eating Index (HEI)), and food preference and perception assessments. Food taste intensities were influenced by sex with bitter and umami taste intensities of several foods being perceived more intensely by males. Moreover, food liking was largely influenced by ethnicity with Hispanics having higher liking ratings for several foods compared with non-Hispanics. Both, Hispanics and females, had higher total fruit HEI scores and lower attention scores than non-Hispanics and males, respectively. Females also had lower blood pressure, reactive hyperemia index, and fasting blood glucose. Food-insecure individuals rated cost and convenience as more important factors for overall food consumption and had lower attention scores than those with higher food-security status. Future research should consider the complex interactions of factors such as taste and flavor perception, sex, ethnicity, prior exposure to foods, and other environmental factors when studying food preferences and health in young adults.

Characterization of flavor perception and characteristic aroma of traditional dry-cured fish by flavor omics combined with multivariate statistics

Traditional dry-cured fish has a rich aroma and has been favored by consumers. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-olfactory-mass spectrometry (GC-O-MS) was used to identify the aroma components of traditional dry-cured fish. A total of 39 volatile compounds were identified by GC-O-MS, and 17 compounds had odor activity values greater than 1. Aroma recombination model was prepared by mixing 17 volatile compounds from sun-dried fish with an odorant activity value greater than 1 in an odorless matrix. The odorless base had a good similarity to the aroma of dry-cured fish. Seven sensory attributes were selected to describe the aroma of dry-cured fish, namely fishy, fatty, meaty, grassy, ground, rancid, and metallic. The electronic nose and multivariate statistical results showed that there were differences in the aroma of dried cured fish with different traditional drying methods. Sun-dried fish had a strong oily, meaty and metallic taste, while shade-dried fish had strong fishy, grassy, earthy, and rancid odors. Omission tests indicated that hexanal, nonanal, octanal, heptanal, 2-octanal,(E)-, 2-nonenal,(E), 3-methylbutanal, pentanol, hexanol, nonanol, heptanol, 1-octen-3-ol, 2-octen-1-ol,(E)-, 2-pentyl furan and d-limonene are characteristic aroma compounds of dry-cured fish.

Characterization of tongue dorsum microbiome in wine tasters

Taste plays a paramount role in food and beverage choice, with recent studies pointing to a potential influence of the microorganisms from the tongue dorsum - particularly bacteria - on flavor perception. Thus, the association between tongue dorsum biofilm and taste is a fundamental prerequisite for a better understanding of the role played by these bacteria in wine tasting. To study this impact, we have analyzed the microbiomes from 58 samples of the tongue dorsum surface from professional wine tasters and 30 samples from non professional wine tasters. The microbiome of each sample was characterized through metagenome sequencing of the 16S rRNA gene for taxonomic discrimination of bacteria. A total of 497 taxa were identified in the tongue dorsum, and significant differences in diversity were observed between the wine taster and the control group. The comparison of bacterial diversity between samples collected before and after wine tasting along with the presence of new bacterial taxa indicates a direct effect of wine on the microbiome of frequent wine tasters, particularly in those tasting sparkling wines.

Chardonnay Marc as a New Model for Upcycled Co-products in the Food Industry: Concentration of Diverse Natural Products Chemistry for Consumer Health and Sensory Benefits.

Research continues to provide compelling insights into potential health benefits associated with diets rich in plant-based natural products (PBNPs). Coupled with evidence from dietary intervention trials, dietary recommendations increasingly include higher intakes of PBNPs. In addition to health benefits, PBNPs can drive flavor and sensory perceptions in foods and beverages. Chardonnay marc (pomace) is a byproduct of winemaking obtained after fruit pressing that has not undergone fermentation. Recent research has revealed that PBNP diversity within Chardonnay marc has potential relevance to human health and desirable sensory attributes in food and beverage products. This review explores the potential of Chardonnay marc as a valuable new PBNP ingredient in the food system by combining health, sensory, and environmental sustainability benefits that serves as a model for development of future ingredients within a sustainable circular bioeconomy. This includes a discussion on the potential role of computational methods, including artificial intelligence (AI), in accelerating research and development required to discover and commercialize this new source of PBNPs.

Biomedical gastronomy in the interventions of smell and taste disorders in ‘altered eating’

Biomedical gastronomy in the interventions of smell and taste disorders in ‘altered eating’

Sensory preferences and requirements amongst Swedish older adults with motoric eating difficulties.

Finger foods, foods that can be eaten without cutlery, may be a strategy to increase autonomy and food intake amongst older adults with motoric eating difficulties. In order to develop optimal finger foods, knowledge about sensory preferences and requirements in the target population is needed. To assess sensory preferences and requirements amongst Swedish older adults with motoric eating difficulties. Check-all-that-apply (CATA), a methodology that does not require much cognitive effort, was used to collect survey data about sensory preferences and requirements for everyday meals from 15 older adults with motoric eating difficulties. The CATA-questionnaire was structured according to the Swedish meal order (breakfast, lunch, dinner, snack and fika) and consisted of 29 attributes compiled through a literature review. Through both qualitative and quantitative data analysis, it was found that flavourful, flavour intensity, spicy and both Swedish and ethnic flavours were important attributes related to food flavour. Although most participants preferred crispy and coarse textures, a few participants found soft, smooth and fine textures important. Moreover, colourful meals and serving components separated on the plate were important for the appearance of lunch and dinner. A diverse range of flavours, flavour enhancement and a balance between the basic tastes and spiciness may increase the flavour perception. Finger foods should be offered in the full range of flavours available to the general older adults' population. The variation in the demand for texture may be related to chewing and swallowing difficulties, and textures that require moderate chewing and easy swallowing are, therefore, optimal for finger foods. Separating meal components on the plate may make it easier to distinguish the components. Chemosensory impairments, chewing and swallowing difficulties, and visual disturbances are important to consider in the development of finger foods.

The role of perireceptor events in flavor perception

The sensory perception of food is a complex phenomenon involving the integration of different stimuli (aroma, taste, trigeminal sensations, texture and visual). Flavor compounds activate odorant, taste and trigeminal chemoreceptors, generating a depolarization of the sensory neurons and then the consciousness of food flavor perception. Recent studies are increasingly highlighting the importance of perireceptor events, which include all the molecular events surrounding the receptors, in the modulation of flavor perception. These events affect the quantity and quality of flavor compounds in the environment of chemoreceptors. They include the metabolization of flavor compounds by enzymes present in biological fluids (saliva and mucus) and the oronasal epithelia and noncovalent interactions with binding proteins. Perireceptor mechanisms have been extensively studied in insects and mammals, demonstrating the importance of the entailed processes in the termination of the chemical signal. In humans, research is in full swing. Here, we reviewed the perireceptor mechanisms recently reported in vitro, in biological fluids and in cells and in vivo in humans. These studies indicate that perireceptor mechanisms likely have an important contribution to flavor perception. This mini-review focuses on recent pioneering studies that are paving the way for this new research area. It also suggests that new approaches taking into account the real conditions of food consumption will be required in the future to accurately address this question.

Chemosensory Functions After Glossectomy-A Cross-Sectional Pilot Study.

To evaluate potential interactions and compensatory mechanisms of subjectively impaired taste function with ortho- and retronasal olfaction after glossectomy. In this cross-sectional pilot study, chemosensory functions were assessed in 25 patients with tongue carcinomas after glossectomy. The orthonasal-, retronasal-, and gustatory functions were tested with a mean time of 25 months after surgery with the Sniffin' Sticks odor identification test kit (ISST), the Candy Smell-27 test (CST-27) and the Taste strip test (TST). Visual analog scales (VAS) were additionally used for self-assessment of taste, flavor perception, and odor ranging from 0 (no perception) to 10 (excellent perception) and further correlated with our psychophysical evaluated outcome measures. The TST, ISST, and CST-27 tests revealed that only eight (32%) and 13 (52%) glossectomy patients had normal taste and orthonasal function, e 21 (84%) patients showed normal retronasal function. Importantly, neither extent of resection and reconstruction nor prior radiotherapy affected chemosensory functions. Contrary, 20 (80%) patients rated their taste and flavor perception as acceptable (VAS >5). Results of the TST, ISST, and CST-27 tests did not correlate with the equivalent self-assessments of taste (p=0.260, r=0.234), odor (p=0.588, r=-0.114), and flavor (p=0.728, r=0.073) perception. There was a significant discrepancy between self-perception of taste and flavor and assessed gustatory function after glossectomy. A contribution of the intact retronasal olfactory system could be a possible explanation of our results. 4 Laryngoscope, 133:375-382, 2023.

A Nasal Aerodynamics Perspective of Retronasal Olfaction: Rodents vs. Humans.

Odor perception can be achieved through ortho or retronasal routes, with the latter being an important component of flavor perception. There are significant olfactory differences that exist between rats and humans and by understanding the role of structural differences, further insight can be gained into the mechanism of odorant perception via ortho or retronasal routes. 3D human and rat (Sprague Dawley) computational models were used to investigate nasal anatomy impact on ortho vs. retronasal odorant transport to the olfactory epithelium. The nasal pharynx region was modified for human and rat models to probe nasal structure impact on ortho vs retro olfaction. 65 odorant absorption rates to the olfactory epithelium were extracted from each model. For human, the retronasal route provided higher peak odorant absorption compared to orthonasal route (left: 90% higher, right: 45% higher), but substantially lowered peak absorption for rat (medial: 97% lower, lateral: 75% lower). For both models, anatomical modification had minimal impact to orthonasal routes, but substantially modulated the retronasal route: decrease (left: -41.4%, right: -44.2%) for human, and increase to the medial (29.5%) but not to lateral (-14.3%) for rat. There exist key differences between humans and rats regarding retro/orthonasal odorant transport routes, which matched well with experimental olfactory bulb activity data in literature. While humans have equivalent odorant delivery between routes, the difference in retro and orthonasal routes in rodents is substantial and changes to the transverse lamina above the nasopharynx can substantially modulate the retronasal route, but not enough to bridge the gap between the two routes.

Defining key parameters and predictive markers of ‘Early Bigi’ cherry consumer satisfaction by means of differential storage scenarios

To induce differences in sensorial characteristics, ‘Early Bigi’ cherries were exposed to various storage scenarios, including modified atmosphere packaging, 1-methylcyclopropene and methyl jasmonate treatments. Three classes of consumer acceptance (high, medium, and low) were defined and related to changes in standard quality, flavour perception and volatile organic compounds (VOCs) emissions. Consumer satisfaction in ‘Early Bigi’ cherries strongly depended on the acidity levels of the fruit and how the storage scenario modulated this parameter. Multivariate data analysis also revealed a clear relationship between acidity, VOCs emissions and flavour perception that determined fruit acceptance. In this cultivar, flavour perception and consumer satisfaction were also linked to specific volatile compounds. At harvest and during the first 15 d of cold storage, consumer satisfaction was found to mainly depend on high levels of ethyl butanoate, (Z)-3-hexen-1-ol and benzaldehyde and on the other side on low levels of ethyl acetate and ethanol, which were probably perceived as off-flavours or unpleasant compounds. Consumer satisfaction was also related to low levels of 2-methylbutyl butanoate, (Z)-2-hexenyl acetate, linalool and 3-methyl-2-butanol. It is, therefore, possible to envisage the use of these specific volatile compounds as markers for consumer satisfaction in ‘Early Bigi’ cherries and perhaps also in other cherry cultivars.

Neural Representation of Intraoral Olfactory and Gustatory Signals by the Mediodorsal Thalamus in Alert Rats.

The mediodorsal thalamus is a multimodal region involved in a variety of cognitive behaviors, including olfactory attention, odor discrimination, and the hedonic perception of flavors. Although the mediodorsal thalamus forms connections with principal regions of the olfactory and gustatory networks, its role in processing olfactory and gustatory signals originating from the mouth remains unclear. Here, we recorded single-unit activity in the mediodorsal thalamus of behaving female rats during the intraoral delivery of individual odors, individual tastes, and odor-taste mixtures. Our results are the first to demonstrate that neurons in the mediodorsal thalamus dynamically encode chemosensory signals originating from the mouth. This chemoselective population is broadly tuned, exhibits excited and suppressed responses, and responds to odor-taste mixtures differently than an odor or taste alone. Furthermore, a subset of chemoselective neurons encodes the palatability-related features of tastes and may represent associations between previously experienced odor-taste pairs. Our results further demonstrate the multidimensionality of the mediodorsal thalamus and provide additional evidence of its involvement in processing chemosensory information important for ingestive behaviors.SIGNIFICANCE STATEMENT The perception of food relies on the concurrent processing of olfactory and gustatory signals originating from the mouth. The mediodorsal thalamus is a higher-order thalamic nucleus involved in a variety of chemosensory-dependent behaviors and connects the olfactory and gustatory cortices with the prefrontal cortex. However, it is unknown how neurons in the mediodorsal thalamus process intraoral chemosensory signals. Using tetrode recordings in alert rats, our results are the first to show that neurons in the mediodorsal thalamus dynamically represent olfactory and gustatory signals from the mouth. Our findings are consistent with the mediodorsal thalamus being a key node between sensory and prefrontal cortical areas for processing chemosensory information underlying ingestive behavior.

The Effects of Cranberry Polyphenol Extract (CPE) Supplementation on Astringency and Flavor Perception as a Function of PROP Taster Status and Other Individual Factors.

This study investigated whether PROP (6-n-propylthiouracil) taster status and other individual factors (gender, ethnicity, BMI, and age) are markers of variation in perceptions of astringency and other flavor attributes. Participants (n = 125) evaluated cranberry juice cocktail samples (CJC) supplemented with cranberry-derived polyphenol extract (CPE, added at 0, 0.3, 0.5 and 0.75 g/L), as well as control samples, unsweetened cranberry juice (CJ) and an aqueous solution of 0.75 g/L CPE. Subjects evaluated samples for key sensory attributes and overall liking using a 15 cm line scale. The data were analyzed using ANCOVA and machine learning tools (regression trees and random forest modeling) to examine if the latter approach would extract more meaningful insights about the roles of personal factors in sensory perceptions of cranberry-derived stimuli. ANCOVA revealed robust stimulus effects, but no effect of PROP taster status on astringency perception was observed. Several effects of PROP×gender, ethnicity, and other factors were observed on other sensory attributes and liking. ANCOVA and machine learning tools yielded similar findings, but regression trees provided a more visualized framework. These data show that PROP taster status has a limited role in astringency perception in complex samples and that other personal factors deserve greater focus in future research on astringency perception.

Sound pleasantness influences the perception of both emotional and non-emotional foods

Sounds elicit emotional responses that can influence the perception of food. However, the effects of sounds upon the perception of emotional and non-emotional foods have yet to be fully elucidated. The present study was designed to investigate how pleasant and unpleasant sounds influenced both perception and emotion responses during the consumption of chocolate milkshake (CM) and vegetable ice cream, representing emotional non-emotional foods, respectively. The temporal changes in perceived flavour were documented using the temporal dominance of sensations (TDS) method. In addition, ratings of liking, affective states, and emotional state were determined following the consumption of milkshake and ice cream. Canonical variate analysis (CVA) was used to further summarise the standardised duration of flavour of CM, liked vegetable ice cream (LV), and less liked vegetable ice cream (LLV) consumed under different sound conditions. Multivariate analysis revealed significant differences between the standardised duration of flavours of CM, LV, and LLV perceived under the pleasant sound (PS) and unpleasant sound (US) conditions. Additionally, flavour perception, affective states, and emotional responses varied with CM, LV, and LLV under the PS and US conditions. These findings contribute to a better understanding of how sounds that vary in pleasantness can influence the perceptual dynamics of emotional and non-emotional foods.

Endogenous hydrocortisone caused metabolic perturbation and nutritional deterioration of animal-derived food in a dose-dependent manner

Endogenous hydrocortisone causes detrimental effects on public health and domestic animal products, but the potential mechanisms remain elusive. Hydrocortisone was detected from seventy-two Guanzhong-Black pigs in three replicates (216 samples) (0.00 ± 46.38 μg kg−1), indicating the existence of endogenous hydrocortisone. Herein, we investigated the effects of hydrocortisone on the metabolic signatures in pork via integrative metabolomics and proteomics by UHPLC-Q-Orbitrap HRMS. Animal-derived foods under hydrocortisone-bioaccumulation cause metabolic perturbation by regulating glutamine synthetase expression at the transcriptional level contributed to hydrocortisone-induced toxicity and accelerating the down-regulation of essential amino acids (l-Histidine 10.74–6.48 mg kg−1, l-Phenylalanine 3.70–1.57 mg kg−1), purine nucleotides (GMP 40.29–5.00 μg kg−1, etc) that provide nutritional value in a positive feedback loop. Protein-metabolite interactions suggesting that hydrocortisone enhanced nitric oxide synthase and GMP reductase expression (LOQ 3.24–63.39 μg kg−1), and affected meat flavor perception, eventually lead to the decline of nutritional value and flesh quality of pork.

Beyond aroma: A scoping review on the impact of chronic rhinosinusitis on retronasal olfaction.

BackgroundRetronasal olfaction (RNO) refers to the perception of odorants inhaled through the mouth and carried through the nasopharynx to olfactory receptors within the olfactory cleft, enabling the perception of flavor. Although orthonasal olfactory dysfunction in chronic rhinosinusitis (CRS) has been widely described, the impact of CRS on RNO is less clear. In this study, we systematically review available literature to provide an update on RNO in the setting of CRS.MethodsWe systematically searched PubMed, Ovid Embase, Web of Science, and the Cochrane Library for studies examining RNO in patients with documented CRS. The primary outcome of interest was objective psychophysical measurement of olfaction, including characterization of RNO.ResultsWe identified 404 unique references that underwent title and abstract review by two independent reviewers, with 52 articles undergoing full-text review, where 10 relevant studies underwent data extraction. Although outcome measures varied, all included studies demonstrated diminished RNO in patients with CRS. Of six studies evaluating the relationship between retronasal and orthonasal olfactory test scores in CRS patients two out of six (33%) demonstrated a correlation between both forms of olfaction and CRS, and two out of six studies (33%) found significantly lower orthonasal olfactory test scores compared to retronasal olfactory test scores. Two of three found significant improvement in RNO with treatment of underlying CRS. Of three studies examining patient reported outcome measures (PROMs) in CRS, two found significant associations between retronasal olfactory test scores and PROMs.ConclusionsBased on the current literature, CRS patients appear to have diminished RNO, which may be associated with orthonasal olfactory dysfunction and decreased quality of life in this population. Higher level of evidence studies are required to further elucidate these relationships and the impact of medical and surgical CRS management on RNO.

Odor-Induced Taste Enhancement Is Specific to Naturally Occurring Temporal Order and the Respiration Phase.

Interaction between odor and taste information creates flavor perception. There are many possible determinants of the interaction between odor and taste, one of which may be the somatic sensations associated with breathing. We assumed that a smell stimulus accompanied by inhaling or exhaling enhances taste intensity if the order is congruent with natural drinking. To present an olfactory stimulus from the identical location during inhalation and exhalation, we blocked the gap between the tube presenting the olfactory stimulus and the nostril. Participants breathed and ingested the solution according to the instructions on the screen and evaluated the solution's taste intensity. Vanilla odor enhanced the sweet taste in both retronasal and orthonasal conditions when the order of stimuli was congruent with natural drinking, but it did not do so in either condition when they were incongruent. The results suggest that breathing is a determinant of odor-taste interaction. The methods of presenting olfactory stimuli used in this study were compared and discussed in relation to those used in previous studies. Odor-induced taste enhancement depends on the time order of smell with breathing and taste congruency in natural drinking. Taste enhancement was induced by odor in both conditions by minimizing differences in odor presentation between them.

Long-term quality-of-life impairment in patients with more than 1-year COVID-19-related olfactory dysfunction.

Long-term quality-of-life impairment in patients with more than 1-year COVID-19-related olfactory dysfunction.

Relationships between Instrumental and Sensory Quality Indices of Shine Muscat Grapes with Different Harvesting Times.

The effects of instrumental quality indices on the sensory properties of Shine Muscat grapes harvested 16, 18, 20, and 22 weeks after full bloom (WAFB) were investigated. The berries harvested at 20 and 22 WAFB gained higher sweetness scores than those harvested at 16 and 18 WAFB, showing similar trends to that of total soluble solids (TSS) content. The sourness, astringency, and firmness scores were not significantly different among the samples. The flavor score showed a trend similar to that of sweetness perception. The higher flavor score in the berries harvested at 20 and 22 WAFB seemed to be derived from the development of floral aroma compounds, including linalool and its derivatives, with ripening. Consumer acceptance was highly correlated with sweetness and flavor perceptions. It was concluded that the TSS content and development of floral aroma compounds are the key quality parameters for Shine Muscat grapes, satisfying consumer acceptability in the market.