口腔加工与鼻后嗅觉

… and retronasal olfaction in neuronal processing and … in oral processing, bite size, duration of processing and meal duration. Small bite sizes and longer duration of oral processing favor …

… of olfactory eloquent areas in favor of ortho-nasal odor presentation while activations of mechanosensory areas were favored by the retro-nasal odor route. As effect of oral stimuli we …

… between orthonasal and retronasal smelling (P = .26), in NP patients, olfactory function was … retronasal route (P < .001). Ratings of general olfactory abilities correlated with retronasal …

… orthonasal and retronasal olfaction. … processing in the orthonasal pathway, suggests that a similar phenomenon may occur during passage of odorants along the much longer retronasal …

Aroma is an important property of fermented milk, and it directly affects consumer acceptance. However, previous studies have mainly focused on analyzing the composition of aroma compounds in fermented milk in vitro, and the composition may be different from the real aroma composition that stimulates the sense of smell. Furthermore, the relationship between olfactory attributes and the release of aroma compounds was not fully understood. In this study, we selected 6 samples of fermented milk differing in aroma perception intensity based on our pretest. A descriptive sensory analysis focusing on orthonasal and retronasal olfaction of fermented milk was first conducted by semitrained panelists. Artificial saliva was mixed with the fermented milk samples and continuously stirred at 37°C for 15 s to simulate oral processing conditions. Headspace solid-phase microextraction-gas chromatography coupled with quadrupole time-of-flight mass spectrometry was applied to identify the head space composition of 6 kinds of fermented milk before and after the simulated oral processing. Twenty-five volatile compounds were identified in the fermented milks, 15 of which were predicted to have an influence on the olfactory perception of fermented milks during oral processing. Partial least squares regression analysis based on chemical and sensory data was then applied to explore the correlation between sensory perception and volatile aroma release. The results showed that oral processing greatly increased the perception of creamy aroma compounds, such as diacetyl and acetone, but did not increase the perception of dairy sour aroma compounds, such as butanoic acid and hexanoic acid. This study can help improve our understanding of the relationship between olfactory perceptions and the release of volatile aroma compounds under oral processing. It might also contribute to the design of palatable fermented milks catering to specific consumer preferences.

Abstract The dynamic and complex peculiarities of the oral environment present several challenges for controlling the aroma release during food consumption. They also pose higher requirements for designing food with better sensory quality. This requires a comprehensive understanding of the basic rules of aroma transmission and aroma perception during food oral processing and its behind mechanism. This review summarized the latest developments in aroma release from food to retronasal cavity, aroma release and delivery influencing factors, aroma perception mechanisms. The individual variance is the most important factor affecting aroma release and perception. Therefore, the intelligent chewing simulator is the key to establish a standard analytical method. The key odorants perceived from the retronasal cavity should be given more attention during food oral processing. Identification of the olfactory receptor activated by specific odorants and its binding mechanisms are still the bottleneck. Electrophysiology and image technology are the new noninvasive technologies in elucidating the brain signals among multisensory, which can fill the gap between aroma perception and other senses. Moreover, it is necessary to develop a new approach to integrate the relationship among aroma binding parameters, aroma concentration, aroma attributes and cross-modal reactions to make the aroma prediction model more accurate.

… between synchronous tactile (texture) and olfactory (odor) sensations, using a … or retronasally after oral processing and before swallowing the oral stimulus or in the absence of an oral …

… Accordingly, amplitudes and latencies of olfactory event-related potentials to retronasal … This indicates differential processing of olfactory stimuli presented through the retronasal or …

… properties upon ortho- versus retronasal olfaction, we probed for differential activity … processing of the orthonasally sensed chocolate odor involves the integration of neural processing …

Background: This report produces a bibliographic study of psychophysical tests proposed clinical assessments of retronasal olfaction. Aims: We review how these tests can be utilized and discuss their methodological properties. Study Design: Systematic review. Methods: We undertook a systematic literature review investigating the retronasal olfaction test methods. PubMed, the free online MEDLINE database on biomedical sciences, was searched for the period from 1984 to 2015 using the following relevant key phrases: “retronasal olfaction”, “orthonasal olfaction”, “olfaction disorders”, and “olfaction test”. For each of the selected titles cited in this study, the full manuscript was read and analyzed by each of the three authors of this paper independently before collaborative discussion for summation and analytical reporting. Two reviewers independently read the abstracts and full texts and categorised them into one of three subgroups as follow, suitable, not-suitable, and unsure. Then they cross-checked the results, and a third reviewer decided assigned the group “unsure” to either the suitable group or the not-suitable group. Fifty eight studies revealed as suitable for review by two authors whereas 13 found not suitable for review. The total amount of 60 uncertain (unsure) or differently categorized articles were further examined by the third author which resulted in 41 approvals and 19 rejections. Hence 99 approved articles passed the next step. Exclusion criteria were reviews, case reports, animal studies, and the articles of which methodology was a lack of olfaction tests. By this way excluded 69 papers, and finally, 30 original human research articles were taken as the data. Results: The study found that the three most widely used and accepted retronasal olfaction test methods are the retronasal olfaction test, the candy smell test and odorant presentation containers. All of the three psychophysical retronasal olfaction tests were combined with orthonasal tests in clinical use to examine and understand the smell function of the patient completely. There were two limitations concerning testing: “the lack concentrations and doses of test materials” and “performing measurements within the supra-threshold zone”. Conclusion: The appropriate test agents and optimal concentrations for the retronasal olfaction tests remain unclear and emerge as limitations of the retronasal olfaction test technique. The first step to overcoming these limitations will probably require identification of retronasal olfaction thresholds. Once these are determined, the concept of retronasal olfaction and its testing methods may be thoroughly reviewed.

… Orthonasal olfaction occurs when odor molecules are sampled via nasal inhalation or sniff… olfactory receptors through the nose. The key issue for the investigation of retronasal olfaction …

… category-specific processing occurs in olfaction. Since domain… existence of category-specific processing in olfaction. In their study … that orthonasal and retronasal olfaction represent two …

… of retronasal olfactory testing that resembles everyday challenges to retronasal olfactory … Apart from these factors, information-processing patterns and interactions with other oral …

The aim of the study was to develop a test for the assessment of retronasal olfaction in healthy participants and patients with olfactory disorders using “tasteless” powders.

… retronasal olfaction might be processed differently. Retronasal olfaction is the perception of odors emanating from the oral cavity during eating and drinking, as opposed to orthonasal …

… the retro-nasal sensation of orally ingested nonvolatile taste compounds was caused by the aerosol generated during food oral processing… the olfactory epithelium; the 2 oral processing …

… in the mouth or not, odors are referred to the oral cavity and the tongue when food odors reach the olfactory epithelium via the retronasal route. This result agrees with the past research …

… We hypothesized that if the 2 olfactory routes generate similar percepts, retronasal learning should transfer to orthonasal recognition. We predicted that rats would perform better or …

… and retronasal olfaction. The sense of smell has a profound influence on the perception of flavor … on the impact of selected flavor and media on ortho- and retronasal flavor perception. …

The human sense of smell constitutes the main part of flavor perception. Typically, patients with loss of olfactory function complain of diminished perception during eating and drinking. However, some patients with smell loss still report normal enjoyment of foods. The aim of the present study was to compare orthonasal and retronasal olfactory function in patients with non‐sinonasal smell loss and subjectively normal flavor perception.

… that taste can enhance the perception of retronasal odor … that retronasal odors can enhance the perception of taste. … The function of retronasal odor enhancement in flavor perception is …

… of the taste-smell illusion. Finally, according to our results, there is a definite suppression of retronasal aroma perception by gustation: we observed significantly more errors in aroma …

… To assess the influence of orthonasal and retronasal stimulation on cross-modal interactions between texture and flavor perception of food, a series of experiments have been conducted…

… participants could not perceive the retronasal aroma of yokan enough with … perceived the retronasal aroma of yokan with moderate intensity. Although the intensity of retronasal aroma …

… Orthonasal or retronasal presentation of odorants evokes … that allows ortho- or retronasal presentation of chemosensory … differences in the perception of ortho- and retronasal stimuli. The …

… The goal of this study was to investigate the cortical representation of olfactory perception in response to ortho- and retronasal stimulation using fMRI7,46,47 In this preliminary study, …

… These observations extend our understating of the role of retro-nasal sensation in the flavor perception of food and beverages, and provide food industry alternative strategies of sugar-…

… It is hypothesized that differences in the extent of retronasal aroma … in perceived intensity, duration, or quality of retronasal aroma stimulation. Therefore, the effect of retronasal aroma …

Abstract Cross-modal sensory integration plays a key role in food flavor perception and acceptance during consumption. The current study investigated the effect of a butter odor, delivered at various stages of the oral processing cycle, on modulating the sensory properties of cheese. Twenty healthy volunteers (aged between 25 and 29 years, 12 women) were measured for their detection thresholds for the butter odor. In the sensory evaluation sessions, participants chewed and swallowed three types of cheese (low-fat, 20% fat content, LF; a medium-fat, 30% fat content, MF; high-fat, 40% fat content, HF, served in 16 × 16 × 12 mm3 cubes) while the butter odor was presented ortho- and retronasally in two concentrations at various points of the oral processing cycle. After swallowing, participants rated on a visual analogue scale for the intensities of cheese creaminess, butter note, overall flavor, and the pleasantness for cheese texture. Enhancement of added butter odor on perceived sensory attributes differed as a function of the delivery routes and timings. Creaminess intensity increased significantly when butter odor presented retro-nasally at the start of chewing. Butter note was enhanced when the retro-nasal odor was added during chewing. The texture pleasantness was increased with ortho-nasal odor presentation. In addition, for the creaminess intensity and texture liking enhancement, the observed effects were more pronounced with butter odor presentation at the lower concentration. Taken together, these findings suggested the importance of temporal congruency for cross-modal sensory enhancement in food flavor perception. The findings help to better understand flavor perception during oral processing of solid food and add value for future development of foods with nutritional benefits.

Summary Smells can arise from a source external to the body, and stimulate the olfactory epithelium upon inhalation through the nares (orthonasal olfaction). Alternatively, smells may arise from inside the mouth during consumption, stimulating the epithelium upon exhalation (retronasal olfaction). Both ortho- and retronasal olfaction produce highly salient percepts, but the two percepts have very different behavioral implications. Here, we use optogenetic manipulation in the context of a flavor preference learning paradigm to investigate differences in the neural circuits that process information in these two sub-modalities of olfaction. Our findings support a view in which retronasal, but not orthonasal odors share processing circuitry commonly associated with taste. First, our behavioral results reveal that retronasal odors induce rapid preference learning, and have a potentiating effect on orthonasal preference learning. Second, we demonstrate that inactivation of the insular gustatory cortex selectively impairs expression of retronasal preferences. Thus, orally-sourced (retronasal) olfactory input is processed by a brain region responsible for taste processing, whereas externally-sourced (orthonasal) olfactory input is not.

It is suggested that the brain response of a food odour sensed retro-nasally is related to satiation. The extent of retro-nasal aroma release during consumption depends on the physical structure of a food, i.e. solid foods generate a longer, more pronounced retro-nasal aroma release than liquid foods. The aim of this study was to investigate if a beverage becomes more satiating when the retro-nasal aroma release profile coincides with the profile of a (soft) solid food. In a double-blind placebo-controlled randomised cross-over full factorial design, twenty-seven healthy subjects (fourteen males and thirteen females; aged 16–65 years; BMI 19–37 kg/m(2) were administered aroma profiles by a computer-controlled stimulator based on air dilution olfactometry. Profile A consisted of a profile that is obtained during consumption of normal beverages. Profile B is normally observed during consumption of (soft) solids. The two profiles were produced with strawberry aroma and administered in a retro-nasal fashion, while the subjects consumed a sweetened milk drink. Before, during and after the sensory stimulation, appetite profile measurements were performed. Subjects felt significantly more satiated if they were aroma stimulated with profile B (P = 0·04). After stimulation with sweet strawberry aroma, there was a significant decrease in desire to eat sweet products (P = 0·0001). In conclusion, perceived satiation was increased by altering the extent of retro-nasal aroma release.

The Duality of Smell hypothesis suggests odorants delivered orthonasally elicit different sensations compared with those delivered retronasally despite activating the same receptors in the olfactory epithelium. Presently, we investigated this further using a matching paradigm free from odorant or semantic memory bias. Subjects were asked to evaluate an aroma delivered in one condition (orthonasal or retronasal delivery) and match the same aroma from 4 unknowns evaluated in the same or different delivery conditions. Panelists matched flavors in 4 delivery conditions: orthonasal-orthonasal, retronasal-retronasal, retronasal-orthonasal, and orthonasal-retronasal. For orthonasal presentation, panelists smelled samples using their nostrils, and for retronasal presentation, panelists swallowed aqueous flavors. In Experiment 1, panelists were instructed to match familiar flavors (banana, grape, orange, raspberry). In Experiments 2 and 3, panelists used the same experimental design with either 4 unfamiliar flavors (kinnow, longan, pawpaw, prunus) or 4 distinct subtypes of a strawberry flavor (woody, green, ripe, candy). In Experiment 1, the number of correct matches in each condition did not significantly differ suggesting stability in the perceptual construct across delivery routes. However, in Experiments 2 and 3, significantly more samples were correctly matched in the orthonasal-orthonasal and retronasal-retronasal conditions compared with the retronasal-orthonasal or orthonasal-retronasal conditions suggesting aroma perception is dependent on delivery route. Additionally, across the 4 delivery methods, the ability to correctly match flavors decreased as flavor familiarity decreased or similarity increased and may reflect the different cognitive strategies employed by subjects when matching these stimuli. Our results suggest odorant percepts are route-dependent and consistent with the Duality of Smell phenomenon.

… wine acidity perception and reduced wine’s flower, stone fruit, and tropical fruit aroma intensity (P … Meanwhile chicken significantly reduced average retronasal aroma release intensity of …

In this study, we examined the mode of metabolism of food odorant molecules in the human nasal/oral cavity in vitro and in vivo. We selected 4 odorants, 2-furfurylthiol (2-FT), hexanal, benzyl acetate, and methyl raspberry ketone, which are potentially important for designing food flavors. In vitro metabolic assays of odorants with saliva/nasal mucus analyzed by gas chromatography mass spectrometry revealed that human saliva and nasal mucus exhibit the following 3 enzymatic activities: (i) methylation of 2-FT into furfuryl methylsulfide (FMS); (ii) reduction of hexanal into hexanol; and (iii) hydrolysis of benzyl acetate into benzyl alcohol. However, (iv) demethylation of methyl raspberry ketone was not observed. Real-time in vivo analysis using proton transfer reaction-mass spectrometry demonstrated that the application of 2-FT and hexanal through 3 different pathways via the nostril or through the mouth generated the metabolites FMS and hexanol within a few seconds. The concentration of FMS and hexanol in the exhaled air was above the perception threshold. A cross-adaptation study based on the activation pattern of human odorant receptors suggested that this metabolism affects odor perception. These results suggest that some odorants in food are metabolized in the human nasal mucus/saliva, and the resulting metabolites are perceived as part of the odor quality of the substrates. Our results help improve the understanding of the mechanism of food odor perception and may enable improved design and development of foods in relation to odor.

The field of aroma release and perception during the oral process has been well studied. However, the traditional approaches have not fully explored the integration of oral biology, microbiology, and neurology to further understand aroma release and perception mechanisms. Herein, to address the existing challenges in this field, we introduce the oral-microbiota-brain axis (OMBA), an innovative framework that encapsulates the interactive relationships among saliva and the oral mucosa, the oral microbiota, and the brain in aroma release and perception. This review introduces the OMBA and highlights its role as a key interface facilitating the sensory experience of aroma. Based on a comprehensive literature survey, the specific roles of the oral mucosa, oral microbiota, saliva, and brain in the OMBA are discussed. This integrated approach reveals the importance of each component and the interconnected relationships within this axis in the overall process of aroma release and perception. Saliva and the oral mucosa play fundamental roles in aroma release and perception; the oral microbiota regulates aroma release and impacts olfactory perception; and the brain's intricate neural circuitry is central to the decoding and interpretation of aroma signals. The components of this axis are interdependent, and imbalances can disrupt aroma perception. The OMBA framework not only enhances our comprehension of aroma release and perception but also paves the way for innovative applications that could heighten sensory experiences.

We hypothesized that interindividual differences in motor activities during chewing and/or swallowing were determining factors for the transfer of volatile aroma from the in-mouth air cavity (IMAC) toward the olfactory mucosa. In our first experiment, we looked for changes in IMAC volume after saliva deglutition in 12 healthy subjects. The mean IMAC volume was measured after empty deglutition using an acoustic pharyngometer device. Based on the time course of the IMAC volume after swallowing, we discerned two groups of subjects. The first group displayed a small, constant IMAC volume (2.26 mL ±0.62) that corresponded to a high tongue position. The second group displayed a progressive increase in IMAC (from 6.82 mL ±2.37 to 22.82 mL ±3.04) that corresponded to a progressive lowering of the tongue to its resting position. In our second experiment, we investigated the relationship between IMAC volume changes after deglutition and the level of aroma release at the nostril. For this purpose, the release of menthone was measured at the nostril level in 25 subjects who consumed similar amounts of a mint tablet. The subjects were separated into two groups corresponding to two levels of menthone release: high (H) and low (L). The mean volume of IMAC was measured during and after empty deglutition. Group H displayed a small, constant amplitude of IMAC volume change after deglutition, while Group L displayed a progressive increase in IMAC. It is likely that Group H continuously released the aroma through the veloglossal isthmus as the mint was consumed, while Group L trapped the aroma in the oral cavity and then released it into the nasal cavity upon swallowing. These results show that the in vivo aroma release profile in humans depends closely on the different motor patterns at work during empty deglutition.

… Aroma perception is an important factor driving food … then reach the receptors located in the nasal cavity, leading to their … appears as a major actor impacting the perception of aroma. …

… route) or retronasally when food is eaten. In the latter case, volatile compounds pass from the pharynx, over the soft palate, and into the nasal cavity. … to mimic in-mouth aroma release. …

… oral cavity and move them through the nasal cavity. If these odorants, while in the nasal cavity, reach the olfactory mucosa … when the pathway between the oral and nasal cavities is open …

… the jaw pumps flavor-enriched air from the mouth into the … passage of aromas from the pharynx to the nasal cavity. The mean nasal airflow between the onset of expiration and the aroma …

Background Recent evidence suggests that a lower extent of the retronasal aroma release correspond to a higher amount of ad libitum food intake. This has been regarded as one of the bases of behavioral choices towards food consumption in obese people. In this pilot study we investigated the hypothesis that saliva from obese individuals could be responsible for an alteration of the retro-nasal aroma release. We tested this hypothesis in vitro, by comparing the release of volatiles from a liquid food matrix (wine) after its interaction with saliva from 28 obese (O) and 28 normal-weight (N) individuals. Methods and Findings Amplicon sequencing of the 16S rRNA V4 region indicated that Firmicutes and Actinobacteria were more abundant in O, while Proteobacteria and Fusobacteria dominated in N. Streptococcaceae were significantly more abundant in the O subjects and constituted 34% and 19% on average of the saliva microbiota of O and N subjects, respectively. The Total Antioxidant Capacity was higher in O vs N saliva samples. A model mouth system was used to test whether the in-mouth wine aroma release differs after the interaction with O or N saliva. In O samples, a 18% to 60% significant decrease in the mean concentration of wine volatiles was detected as a result of interaction with saliva, compared with N. This suppression was linked to biochemical differences in O and N saliva composition, which include protein content. Conclusion Microbiological and biochemical differences were found in O vs N saliva samples. An impaired retronasal aroma release from white wine was detected in vitro and linked to compositional differences between saliva from obese and normal-weight subjects. Additional in vivo investigations on diverse food matrices could contribute to understanding whether a lower olfactory stimulation due to saliva composition can be a co-factor in the development/maintenance of obesity.

The influence of saliva on aroma release from white and red wines was studied in a model mouth system. Aroma compounds were analysed in the dynamic headspace of wines by solid …

Flavour perception is characterised by complex interactions between physicochemical processes (textural properties, aroma … , eg in terms of flavour acceptance and preference, but …

… retronasal route is a primary determinant of their flavor and … produced by materials inside the oral cavity (eg, by increasing … At this time, the soft palate closes the nasal passage, thereby …

Eating rate and bite size are important factors affecting food intake, and we hypothesise the underlying role of oral sensory exposure in this. However, the latter currently lacks objective measuring parameters, but an interesting measure could be the extent ofin vivoretro-nasal aroma release. Second, the literature is ambiguous about overweight subjects differing from normal-weight subjects in eating behaviour. Consequently, we investigated: (1) whether eating behaviour (food intake, eating rate, bite size, number of bites and meal duration) relates to weight status and (2) whether the extent of retro-nasal aroma release relates to eating behaviour and weight status. A matched group (sex, age and dietary restraint) of twenty-seven normal-weight (BMI 21·8 (sd1·6) kg/m2) and twenty-seven overweight/obese subjects (BMI 30·5 (sd5·8) kg/m2) consumed a spiced rice meal and apple pie yogurt on separate test days. The extent of retro-nasal aroma release was measured on a third test day. Mean bite size for spiced rice was significantly (P = 0·03) larger in overweight/obese (10·3 (sd3·2) g)v.normal-weight subjects (8·7 (sd2·1) g). There were no other significant differences in eating behaviour or retro-nasal aroma release between the groups. Eating behaviours were not correlated with BMI or retro-nasal aroma release. Subjects showed consistent eating behaviour for both test products. Eating behaviour might be a characteristic of an individual but not by definition a characteristic for a group of people based on their weight. Given the large sample sizes, necessary according toa posteriorisample size calculations, one needs to consider the relevance of finding a statistically significant difference in eating behaviour between the weight groups in a laboratory setting.

… , to a retro-nasally sensed food odor signals the perception of food and is suggested to be related to satiation (Small et al. 2005). Retro-nasal aroma stimulation is mainly related to the …

… No effects of total dairy fat intake, total dairy product intake or … food fat content solely based on retronasal olfaction. Results also suggest that this ability is unaffected by habitual intake. …

Odor (including flavor) perception plays a major role in dietary behavior. Orthonasal olfactory function (OOF) has been shown to decrease in obese subjects. Changes in retronasal olfactory function (ROF) after weight loss and in the individual significance of olfaction (ISO) in obesity are yet to be investigated. Firstly, 15 obese subjects were recruited in a pilot study and supported to conventionally lose weight. OOF (Sniffin’ Sticks) was measured at the beginning and after 5.6 ± 1.3 months. Eleven subjects re-visited but barely lost weight and no major changes in OOF were observed. Secondly, the body-mass-index (BMI), OOF, and ROF (Candy Smell Test, CST) were recorded in subjectively olfactory-healthy subjects (SOHSs) and additionally the ISO questionnaire was collected in patients with olfactory dysfunction (OD). BMI correlated significantly negatively with odor discrimination (p = 0.00004) in 74 SOHSs and negatively with CST (p < 0.0001) in 66 SOHSs. In 48 SOHSs, there was a gender difference in ISO scores (p = 0.034), but no significant correlation with BMI was found (p > 0.05). ISO scores were significantly higher in 52 OD patients in comparison to SOHSs (p = 0.0382). Not only OOF but also ROF may decline with higher BMI. ISO does not seem to alter with BMI, but olfaction becomes more important once it is consciously impaired.

Gas chromatography-ion mobility spectrometry (GC-IMS) and dynamic quantitative descriptive analysis (D-QDA) were combined to explore the aroma release and perception from the retronasal cavity during bread consumption. D-QDA results elucidated that the sweet, creamy, and roasty notes were the most active attributes during oral processing. The final stage of oral processing had the most complicated changing pattern, followed by the intermediate and initial stages. Thirteen aroma compounds were detected in the retronasal cavity, of which eight had odor activity values (OAVs) greater than 1. The total OAV changing pattern was consistent with the D-QDA results. Addition experiments further confirmed that acetoin, 2,3-butanedione, and 3-(methylthio)propanal were key aroma compounds contributing to retronasal olfaction. 2,3-Butanedione and 3-(methylthio)propanal were both identified as key odorants in the mouth cavity and retronasal cavity during oral processing, but they had 30% loss during the breath delivery from the mouth cavity to the retronasal cavity.

… studies related to food aversions were based on CTA and taste potentiated odor aversion and considered that olfaction exerted a less effective control than taste on food intake. However…

… ) foods if they were stimulated with a longer retronasal odor profile … retronasal odor exposure on the subsequent milk intake, while a later study did establish a 9 % lower food intake …

… of taste, retronasal odor, and … retronasal odor and retronasal odor enhancement by taste would be of great relevance in the studies of individual differences in taste and retronasal odor …

… With this model, while eating, retronasal odors are falsely localized to the oral cavity, … odor presented retronasally increased assessment of creaminess and thickness of milk-like foods (…

… to apple and mango odors. Similar differences between the 2 … the hedonic value of retronasal odor components of flavor is … food intake, the specific external context in which retronasal …

… and retronasal olfaction decreased with age, while retronasal odor identification tended to decline to a lesser degree than orthonasal olfaction. In addition, retronasal odor identification …

Abstract Previously, we found bitter and sweet tastes to be positive and negative predictors of vegetable liking and intake. Here, we examined interactions between retronasal olfactory sensations (flavor) and tastes as potential predictors of vegetable liking and intake. Adults (n = 97), diverse in bodyweight (40% overweight/obese), rated green vegetables (asparagus, Brussels sprouts, kale) for flavor (sampled with nose plugged, then unplugged to perceive flavor volatiles) and tastes (bitterness and sweetness). They were phenotyped for genetic variation in taste (propylthiouracil (PROP) bitterness) and taste function (quinine bitterness on the tongue tip relative to whole mouth); vegetable consumption frequency was self-reported. Greater increases in vegetable flavor sensations (difference of nose unplugged v. plugged) were associated with greater vegetable bitterness but not sweetness. Those tasting PROP as most bitter also reported greater flavor sensations (nose unplugged) but not greater flavor increases (difference of unplugged v. plugged). With retronasal flavor input, hedonic ratings increased significantly for asparagus, showed little change for kale, and were highly variability for Brussels sprouts; these ratings did not vary by taste phenotype. Those with greater body mass index reported more hedonic increases with vegetable flavor (difference of unplugged v. plugged). In multivariate modeling, PROP bitterness directly predicted vegetable bitterness and flavor. Vegetable flavor negatively influenced vegetable liking and intake indirectly via bitterness, and showed direct negative effects on vegetable intake. These findings support the need for basic and applied research across the food system (e.g., farm to table) to identify ways to enhance pleasant oral sensations from vegetables (e.g., sensory-guided breeding). More pleasant oral sensations would encourage vegetable consumption in support of healthy eating and body weight, especially for individuals with genetic propensity to experience negative oral sensations from vegetables.

… of actual foods in this group. Hence, the current study was designed to study orthonasal and retronasal food odor perception as well as the taste of foods using foods familiar from real …

… The relationship between chewing, swallowing, breath flow rate and volatile release was investigated for two different confectionery chews. From a population of 35 subjects, subgroups …

… differed among individuals, and this was probably related to their rate of chewing, their frequency of swallowing, and the associated airflow through the nose and mouth. The variation be…

… of volatiles in the mouthspace after swallowing to before … their volatile release patterns were similar for the tomatillo and tomatoes. The green aldehydes released during chewing were …

… volatile flavour compounds into the exhaling air to the nasal compartment. Accordingly, we hypothesised that flavour release from chewing … habitual chewing and natural swallowing at …

… aroma release and perception during the chewing of solid … ) in individuals with different chewing efficiency. By comparing the … release, it was found that individuals with higher chewing …

… so that it can be swallowed. One of the … release of homologous series of hydrophobic volatile compounds from a complex fat/protein/water emulsion at different times of the chewing …

… , aroma release was moderate or even null during chewing and a … volatile compounds can be released in the nasal cavity even when the oral cavity has been emptied by the last swallow…

Dynamic flavor release curves from chewing gum were measured using an Artificial Mouth coupled to the AFFIRM®. A flavor distribution model for chewing gum is proposed, where flavor is present as droplets in both the hydrophilic (water-soluble) and the hydrophobic (water insoluble) parts of the chewing gum and as molecularly dissolved in the hydrophobic part of the gum. During mastication, the flavor droplets in the water-soluble phase are released and responsible for an initial burst release. The flavor droplets captured in the gum-base are pushed towards the interface by mastication and are responsible for the subsequent release. The flavor molecules dissolved in the gum-base, released by diffusion, are only responsible for the release at very long time scales. It was found that the oil-water partition constant is an important parameter to explain the flavor release, where hydrophobic components show slower and longer release, while more hydrophilic components show more burst release.

… measuring the total amount of volatiles released (sum of tire 11 … some volatiles did persist after swallowing. In the sucking … in a slower release of all three volatiles compared to chewing. …

… foods affects the chewing and therefore the volatile release during eating. Disruption of plant or animal tissue during chewing might result in in-mouth (enzymatic) generation of volatiles. …

… systems that should mimic the release of volatiles from food products during consumption. … , swallowing, breath flow, and aroma release and demonstrated that an average chew …

… until swallow; semi-solids and solids were chewed. Subjects were instructed to chew about … absolute amount of volatile release (either pre-swallow or post-swallow) and corresponding …

This study investigated the effects of chewing rate and food composition on in vivo aroma release and perception of composite foods. Bread or sponge cake paired with varying sugar content and viscosity strawberry jams, spiked with citral and limonene, were examined. In-nose release was characterized using Proton-Transfer-Reaction-Time-of-Flight-Mass-Spectrometry (PTR-ToF-MS). Simultaneously, Time-Intensity (TI) profiling assessed citrus aroma perception (n = 8, triplicate) while fast and slow chewing protocols were applied (fast: 1.33 chews/s; slow 0.66 chews/s; each for 25 s). Chewing rate did not significantly impact the area under the curve and maximum intensity of in vivo citral and limonene release and citrus aroma perception. Faster chewing rates significantly decreased the time to reach maximum intensity of aroma release (p < 0.05) and citrus aroma perception (p < 0.001). Faster chewing rates probably accelerated structural breakdown, inducing an earlier aroma release and perception without affecting aroma intensity. Adding carriers to jams significantly (p < 0.05) increased aroma release, while perceived citrus aroma intensity significantly (p < 0.05) decreased regardless of chewing rate. In conclusion, chewing rate affects the temporality of in vivo aroma release and perception without affecting its intensity, and carrier addition increases in vivo aroma release while diminishing aroma perception.

… transport of the released volatiles through the upper airways to … number of chews beyond a rather large number of chews (>… However, swallowing will bring part of the masticated mass in …

… released amount of VOCs in the oral and nasal cavities and sensorial perception. Chewing and swallowing … and nasal cavities; the so-called “swallow breath” then allows for a pulse of …

… common chewing and swallowing rhythm to the panelists should homogenize aroma release … The VAS is a Givaudan-owned olfactometer to deliver controlled quantities of volatiles over …

… They also enabled the study of the behavior of volatile compounds during the swallowing … (with or without swallowing of the product) on both aroma release and perception in the case of …

… retronasal smell is combined with the other senses stimulated by food and drink in the mouth to give the perception of flavor (9, 12, 25). Although there have been numerous studies of …

… Odorants are delivered to the olfactory epithelium via retronasal or orthonasal routes. Retronasal delivery occurs when odorants reach the … Retronasal transport of aroma compounds …

For flavor perception to occur, the chemicals responsible for flavor perception must be released from the food matrix and transported to the flavor receptors in the mouth and nose. The …

This study employed time‐intensity and temporal dominance of sensations analyses to quantify the contribution of the retronasal pathway to sweet perception by comparing the dynamic perception of sucrose and rebaudioside A (Reb A) under conditions with and without a nose‐clip (which physically blocks the retronasal pathway). Results showed that blocking the retronasal pathway significantly reduced both the intensity and duration of sweetness for sucrose and Reb A. Analysis using the newly developed “retro‐taste partition coefficient” revealed distinct temporal patterns of retronasal dependency: Reb A exhibited a higher retronasal contribution in the early phase of perception, whereas sucrose demonstrated a significantly stronger dependency during the later stages. Compared to sucrose, Reb A still shows perceptible gaps in sweetness quality and temporal profile. Furthermore, Reb A elicited pronounced bitterness and astringency, which became more pronounced during the later stages of perception when the retronasal pathway was blocked. This study highlights the critical role of the retronasal pathway in sweet perception and provides a temporal‐dynamic analytical framework along with quantitative tools for the sensory optimization of sweetener formulations.

It has been reported that conditions in space missions alter the taste and perception of orthonasal aroma by astronauts. However, there is limited knowledge of the effects of space environments associated with the sensory perception of mouthfeel and retronasal aromas. This research aimed to study alterations in retronasal aromas and mouthfeel under an immersive space-simulated environment with a simulated microgravity seating position. A total of 12 well-trained panelists evaluated the intensity of different samples for retronasal aromas and mouthfeel using a neutral environment and a space-simulated environment. Non-invasive facial biometrics were also analyzed from participants’ videos using the BioSensory© application. According to the results, in the space-simulated environment the retronasal aroma intensity was perceived to be significantly lower (p < 0.05) than in the neutral environment. The latter was also shown in the multivariate data analysis developed using self-reported and subconscious biometric variables. Regarding mouthfeel perception, the multivariate analysis showed that the intensity of mouthfeel samples was higher in the space-simulated environment. This study contributes to understanding the sensory requirements in space-simulated conditions to optimize and develop specialized food and beverages for long-term space exploration missions.

… Retronasal perception describes the mechanism in which odor molecules present in the mouth are transported … Our research group performed extensive sensory testing with copper (II) …

… may be introduced to olfactory epithelium retronasally when propagated from the oral cavity … sensory receptors that interact with odorants, which are dissolved or actively transported by …

Odorant stimuli can access the olfactory epithelium either orthonasally, by inhalation through the external nares, or retronasally by reverse airflow from the oral cavity. There is evidence that odors perceived through these two routes can differ in quality and intensity. We were curious whether such differences might potentially have a neural basis in the peripheral mechanisms of odor coding. To explore this possibility, we compared olfactory receptor input to glomeruli in the dorsal olfactory bulb evoked by orthonasal and retronasal stimulation. Maps of glomerular response were acquired by optical imaging of transgenic mice expressing synaptopHluorin (spH), a fluorescent reporter of presynaptic activity, in olfactory nerve terminals. We found that retronasally delivered odorants were able to activate inputs to multiple glomeruli in the dorsal olfactory bulb. The retronasal responses were smaller than orthonasal responses to odorants delivered at comparable concentrations and flow rates, and they displayed higher thresholds and right-shifted dose–response curves. Glomerular maps of orthonasal and retronasal responses were usually well overlapped, with fewer total numbers of glomeruli in retronasal maps. However, maps at threshold could be quite distinct with little overlap. Retronasal responses were also more narrowly tuned to homologous series of aliphatic odorants of varying carbon chain length, with longer chain, more hydrophobic compounds evoking little or no response at comparable vapor levels. Several features of retronasal olfaction are possibly referable to the observed properties of glomerular odorant responses. The finding that retronasal responses are weaker and sparser than orthonasal responses is consistent with psychophysical studies showing lower sensitivity for retronasal olfaction in threshold and suprathreshold tests. The similarity and overlap of orthonasal and retronasal odor maps at suprathreshold concentrations agrees with generally similar perceived qualities for the same odorant stimuli administered by the two routes. However, divergence of maps near threshold is a potential factor in perceptual differences between orthonasal and retronasal olfaction. Narrower tuning of retronasal responses suggests that they may be less influenced by chromatographic adsorption effects.

… of a retronasal smell would be indicated by a nasal occlusion effect. Retronasal smells are … injecting a pure airstream through the external nares, preventing retronasal transport [11]. …

… flavors and the sensory interactions at work within them, the first step is to investigate single-compound interactions … possible oral tactile texture prior to the food entering the oral cavity. …

… , and food oral processing. Second, perceptual mechanisms result from sensory information … In this chapter, we propose a review of multimodal interactions in the context of food flavor …

… This multi-faceted sensory experience is the underpinning of perceived flavor, … interact, both on a perceptual and a physical level, and discusses the resulting impact each has on flavor …

… matrix on flavor release, we need to consider firstly how flavor … blocking of taste receptor sites in the oral cavity. A 3rd issue is … ) interact on a cognitive level to generate our final sensory …

… -modal sensory interactions involved in flavor perception have started to provide an understanding of the integrated activity of sensory … by oral somatosensation and retronasal …

Flavor is perhaps the most multi-modal of all of our sensory … flavor is defined as a perception that includes gustatory, oral-… impact flavor perception, it is argued that these sensory signals …

In this chapter, we highlight the crucial role played by the oral-somatosensory attributes of food and drink in determining our perception, and hence our enjoyment, of many of our most …

… interact with host physiology to shape flavor … -flavor interactions through a hierarchical framework: (1) oral secretion-mediated flavor release and modification; (2) microbiota-driven flavor …

… Perceptual interactions between odour and oral texture were explored in a study in which a … filled the oral cavity, during a 3-s period in which the liquid was manipulated orally or during …

… samples that could be used to closer investigate differences in the sensory interactions between the stimulated senses in a liking decision for older and younger consumers. …

… the literature on the multisensory interactions underlying the perception of flavor in order to determine the extent to which it is really appropriate to consider flavor perception as a distinct …

… The sensation of flavor is elicted by a combination of nasal and oral stimulation. Whether … of flavor be altered? For many years, sensory scientists have investigated these interactions …

With consumers gaining prominent awareness of health and well-being, a diverse range of fortified or reformulated novel food is developed to achieve personalized or tailored nutrition using protein, carbohydrates, or fat as building blocks. Flavor property is a critical factor in the acceptability and marketability of fortified or reformulated food. Major food ingredients are able to interact with flavor compounds, leading to a significant change in flavor release from the food matrix and, ultimately, altering flavor perception. Although many efforts have been made to elucidate how food matrix components change flavor binding capacities, the influences on flavor perception and their implications for the innovation of fortified or reformulated novel food have not been systematically summarized up to now. Thus, this review provides detailed knowledge about the binding behaviors of flavors to major food ingredients, as well as their influences on flavor retention, release, and perception. Practical approaches for manipulating these interactions and the resulting flavor quality are also reviewed, from the scope of their intrinsic and extrinsic influencing factors with technologies available, which is helpful for future food innovation. Evaluation of food-ingredient interactions using real food matrices while considering multisensory flavor perception is also prospected, to well motivate food industries to investigate new strategies for tasteful and healthy food design in response to consumers' unwillingness to compromise on flavor for health.

Salt reduction in foods is becoming an important challenge to protect population health from severe diseases as recommended by different health agencies worldwide. Among the reduction strategies already evaluated in order to lower sodium salt content in foods, the use of cross-modal interactions between taste and odour, regardless of saltiness, was revealed to be a very promising method to improve saltiness perception. Cross-modal odour-taste interactions, as means to enhance salty taste in foods, is reviewed. Salt-related odours can enhance salty taste in water solutions containing a low level of sodium chloride through odour-induced changes in taste perception. Odour-induced saltiness perception enhancement (OISE) depends on salt concentration (intensity). OISE was also found to be effective in low salt content solid model cheese but was texture- and composition-dependent. A significant enhancement in saltiness perception induced by Comté cheese and sardine odours was observed only in model foods with soft textures. In ternary odour-sour-salty solutions, sourness additively enhanced saltiness perception with salt-related odours. Finally, in cream-based food systems, a strategy combining OISE and heterogeneous distribution of stimuli was found to compensate for a greater than 35% decrease in salt content without significant loss of acceptability. However, variation in the composition of the food matrix influenced aroma and salt release and consequently the overall saltiness perception. A better knowledge of the mechanisms involved in cross-modal perceptual interactions at the central level should allow for the optimization of their use as salt reduction strategies for healthier food design.

… the perception of volatile flavors in foods? No … flavors (eg, anethole and citral) in solutions presented orally. However, even when presented orally, the perception of such volatile flavors …

Abstract Background Consumers frequently combine foods with different compositions and properties within a meal or within a bite; for example bread with spreads or vegetables with dressings. Such food combinations are called composite foods. Scope and approach This narrative review highlights how (1) addition of food particles and (2) addition of accompanying foods influence oral processing behavior, sensory perception and intake of composite foods. Practical implications, knowledge gaps and future perspectives are also discussed. Key findings Oral processing behavior of composite foods can be modified by changing single food properties. Adding particles, adding accompanying foods or changing single food properties, especially mechanical properties, shape and concentration, are promising approaches to influence eating rate and thereby energy intake. In addition, sensory perception of composite foods is complex, as interactions between foods in mouth imply significant changes in sensory perception. Consequently, sensitivity to discriminate between foods is reduced when a food is assessed together with an accompanying food. Conclusions This review highlights how structural transitions of composite foods during mastication contribute to oral processing behavior, perception and intake of composite foods. This is of particular interest in the design of healthy or sustainable produced foods, for which assuring excellent sensory quality still poses a challenge.

… Together with the application of the SOOM (spit-off odorant measurement)-technique, the exact timing of odorant transfer to the nose as well as the phenomenon of odorant adsorption …

Abstract A conceptual model was developed to relate oral processing parameters and aroma release of cooked white rice. The conceptual model indicates that aroma release is dependent on the increase of particle surface area, the dilution effect of saliva and the diffusion of aroma from food residues that can be trapped in the buccal-pouches in the mouth. The model was validated against in vivo retro-nasal aroma release data during the consumption of rice flavoured with two aroma compounds (2-nonanone and ethyl propanoate) by five panellists. The oral processing behaviour of each subject was characterised at four different stages during oral processing by measuring bolus particle size, saliva content and the amount of residue particles that could be washed from the mouth after bolus expectoration. The results showed that aroma release for all subjects were dependent on the particle breakdown pathways used in oral processing. Subjects who reduced the rice to smaller particle sizes, higher pasted fraction and higher bolus residues had higher aroma release as expected from the conceptual model. Accounting for the physiological variables of subjects, the physicochemical parameters of aroma compounds and using a larger number of subjects in future studies will improve the model reliability.

… the dynamics of flavor release during in-mouth oral processing of food before bolus swallowing. Within this context, the evolution of two aroma compounds during bolus formation was …

The release mechanism of odorants in the oral cavity during consumption directly affects sensory attributes, consumers' preferences, and ultimately purchase intent. Targets was set to monitor in real-time the key odorants released from grilled eel during mastication via an atmospheric pressure chemical ionization mass spectrometry (APCI-MS) connected with a nose interface. The release and perception of odorants during mastication were divided into three distinct phases. Dimethyl sulfide was the main odorant in the first stage. The release and perception of fishy aromas were predominant in the middle and last stages of mastication contributed by trimethylamine, 1-penten-3-ol, and 2-methyl-1-butanol. Chewing behavior experiments suggested that extending the chewing period to >20 s and having a chewing frequency of 2 cycles/s could enhance the aroma delivery of grilled eel and optimize the consumer experience. Consequently, the results explained the relationship between aroma release and the optimal chewing behavior for grilled eel consumption.

Perception of flavor is a dynamic process during which the concentration of aroma molecules at the olfactory epithelium varies with time as they are released progressively from the food in the mouth during consumption. The release kinetics depends on the food matrix itself, but also on food oral processing, such as mastication behavior and food bolus formation with saliva, for which huge inter-individual variations exist due to physiological differences. Sensory methods, such as time-intensity (TI), or the more recent methods temporal dominance of sensations (TDS) and temporal check-all-that-apply (TCATA), are used to account for the dynamic and time-related aspects of flavor perception. Direct injection mass spectrometry (DIMS) techniques that measure in real-time aroma compounds directly in the nose (nosespace), aimed at obtaining data that reflect the pattern of aroma release in real-time during food consumption, supposed to be representative of perception, have been developed since 25 years. Examples obtained with MS operated in chemical ionization mode at atmospheric or sub-atmospheric pressure (atmospheric pressure chemical ionization APCI or proton transfer reaction PTR) will be given, with emphases on studies conducted with simultaneous dynamic sensory evaluation. Inter-individual variations in terms of aroma release and their relevance for understanding flavor perception will be discussed, as well as evidenced cross-modal interactions.

… Faster oral breakdown and higher peak saliva concentrations of non-volatile flavor compounds in high IMF grilled beef were consistent with higher tenderness and more intense flavor …

… such as partitioning of odorants between polar and non-… Then, panellists were instructed to swallow the entire bolus and, … Breakdown of the soft gel and spreading throughout the tongue …

… , with a linear and dynamic range as wide as possible. Several … , as it means that most odorant molecules can be detected … consider the formation of a bolus residue within the pharynx to …

Highlights • Taste perception and texture change during oral processing were characterized.• Twelve flavor compounds increased significantly after chewing of 12 s.• Differential lipids and proteins during bolus formation were analyzed by omics.• Flavor release mechanism of sturgeon meat during oral processing was discussed.

… prepare a model bolus from various gel samples and to subject them to dynamic viscoelasticity … factors, resistance to breakdown and the deformation of the bolus. Therefore, the artificial …

In vivo aroma release and perception of complex food matrices have been underexplored. The aims of this study were to investigate the effects of (i) fat and sugar content of chocolate-hazelnut spreads on in vivo aroma release and perception and (ii) carrier addition (bread, wafer) on in vivo aroma release and perception of chocolate-hazelnut spread using dynamic nose space analysis (PTR-ToF-MS) and dynamic sensory analysis (TCATA). Carriers were combined with spreads varying in fat and sugar content and were spiked with five volatile organic compounds (benzaldehyde, filbertone, 2-methylpyrazine, delta-dodecalactone, isovaleraldehyde). TCATA profiles from a consumer panel without in vivo nose space analysis (n = 72) and a trained panel performing in vivo nose space analysis (n = 8, triplicate) were compared. TCATA profiles of the spread-carrier combinations obtained by both panels showed similarly that attributes related to the carriers were perceived at the beginning of consumption, whereas attributes related to the spreads were perceived after swallowing. Significant (p < 0.05) and small differences were observed for the attributes cocoa, creamy, milky, sticky and toffee between both panels. In the evaluated reformulation range, fat and sugar content of chocolate-hazelnut spreads had only a limited effect on in vivo aroma release and perception. In contrast, addition of carriers strongly affected in vivo aroma release and perception for all target molecules. The addition of carriers to spreads generally increased aroma release (duration and intensity of aroma release) and decreased aroma perception. The addition of carriers generally reduced the time to reach maximum intensity compared to when spreads were eaten alone for the five volatile organic compounds while perception decreased. We conclude that the strong effect of carrier addition on in vivo aroma release and perception of chocolate-hazelnut spreads highlights the importance of investigating toppings/spreads accompanied with carriers rather than in isolation.