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Odor and taste perception at normal and low atmospheric pressure in a simulated aircraft cabin
Abstract
During flights, reduced odor and taste perception is reported. Passengers tend to prefer spicier meals than on the ground.
The conditions on board were simulated at the Fraunhofer flight test facility in Holzkirchen, Germany, consisting of a front
fuselage of an Airbus A310-200 in a huge metal tube in which all relevant parameters can be adjusted (humidity, temperature,
pressure). Flight tests were carried out at low atmospheric pressure corresponding to cabin conditions on board at cruising
altitude and were repeated at normal atmospheric pressure corresponding to ground conditions. All other parameters were kept
constant. Under these conditions, test persons smelled and tasted food-safe flavorants to evaluate the mean odor and taste
thresholds and tasted different flavored food. Even tomato juice and various wines were tasted for odor and taste qualities,
intensities and individual preferences. At low pressure conditions, higher taste and odor thresholds of flavorants were generally
observed with few exceptions. Salt, sugar, glutamate and most odorant thresholds increased clearly. Organic acids and some
bitter tastants showed no change. Transferred to complete meals, more salt, sugar and herbs were necessary on board to serve
meals that tasted similar to the way they did on the ground. Sour ingredients had to be reduced. The odor and taste spectrum
of the beverages investigated changed in various ways. Light and fresh flavors decreased, whereas intensive flavors persisted.
KeywordsOdor perception–Taste perception–Low atmospheric pressure–Threshold of flavorants–Tomato juice
... The lowered cabin air pressure while in flight then deleteriously impacts olfactory and gustatory perception (e.g., Burdack-Freitag, Bullinger, Mayer and Breuer, 2011). The latter researchers conducted a study at the Fraunhofer Institute for Building Physics, showing that the perception of saltiness falls up to 30 percent on a plane, while the sense of sweetness fell by 20 percent, thus explaining why sweetness needs to be ramped up for meals served in the air (Park, 2017). ...
... Certainly, in terms of longer-term health outcomes for frequent travellers, one obvious suggestion would simply be to remove the salt sachet from meal trays on board (cf. Sutherland, Edwards, Shankar and Dangour, 2013), especially given reports from many flight staff that passengers tend to add lots of salt to their food (Burdack-Freitag et al., 2011). One of the other suggestions from chefs is to bring a bottle of Tabasco sauce on board to help spice up dishes in the air (Dunn, 2018) 12 Certainly, it has been noted that Asian dishes tend to stand up well to presentation in the air (Burdack-Freitag et al., 2011). ...
... It has also been suggested that New World wines from high altitude may stand up better in the skies (Smith, 2014;Tyrer, 2014). And wine experts also recommend choosing a fruity red wine (such as Pinot Noir, Rioja, or Malbec), given that perception of these aromatics are likely to be impaired at altitude (Pace, 2017; see also Burdack-Freitag et al., 2011). Acidic-tasting food and wines should be avoided because of the taste's dominance in the air (Burdack-Freitag et al., 2011). ...
Air travel has undoubtedly become a more stressful activity for many passengers in recent years, in part as a result of the global Covid pandemic. Consequently, there has been a growing focus on how to optimize the psychological wellbeing of passengers while in the air. This narrative historical review considers how the passenger experience can potentially be hacked through the more intelligent stimulation of the travellers’ senses. In particular, the focus is on promoting passenger comfort, enhancing the provision of healthy food and beverage options/experiences, facilitating relaxation and sleep and, when appropriate, boosting passengers’ arousal/alertness as well (e.g., prior to arrival). A number of concrete suggestions concerning how to sensehack passenger wellbeing at the various stages while in the air are made.
... Food perception is a complex multisensory experience depending on both taste, smell, and mouthfeel, which collectively form an impression of flavor 6 . Simulation studies have suggested that our sense of taste and smell is generally reduced in low-pressure environments such as airplane cabins, diminishing the perception of flavor intensity of food products [7][8][9][10] . This is thought to be caused by elevated sensory thresholds for detection of tastants in low-pressure environments 5 . ...
... This is thought to be caused by elevated sensory thresholds for detection of tastants in low-pressure environments 5 . Moreover, this transitory impairment of the gustatory and olfactory senses may impair the general enjoyment of food as well 8 . In addition to the low air pressure, several other factors present in a standard commercial airline cabin are also assumed to contribute to this, such as dry recirculating air, cold temperature, and low oxygen levels 5,8,9 . ...
... Moreover, this transitory impairment of the gustatory and olfactory senses may impair the general enjoyment of food as well 8 . In addition to the low air pressure, several other factors present in a standard commercial airline cabin are also assumed to contribute to this, such as dry recirculating air, cold temperature, and low oxygen levels 5,8,9 . While the exact physiology behind these phenomena is not definitively determined, some explanatory mechanisms have been suggested: cold and dry air are impeding the interaction between odorants and olfactory receptors, and low oxygen levels are inducing hypoxia which may modulate receptor functioning 5,11 . ...
Background : It is generally accepted that the human perception of flavor and odor is altered in low-pressure environments such as airplane cabins. This has been demonstrated in several simulation studies, but never in a field study conducted in an authentic environment, and never using wine as the object of study.
Methods : We performed a comparative field study composed of two wine tastings. The first tasting was conducted on board an aircraft flying at standard cruising altitude and the second tasting was conducted at ground level. Subjective taste experience and current mood were evaluated through a validated questionnaire. The study was reported according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guideline.
Results : The study included 22 participants, none of whom had any special training in wine tasting. No statistically significant difference in experienced flavor intensity was found between the high and low altitude tests, with median aromatic intensities of 5 (interquartile range 3.5-6.0) and 5 (interquartile range 4.0-6.5) respectively, measured on a 9-point hedonic scale. Additionally, there was no detectable difference in several other taste parameters.
Conclusions : These findings suggest that even though experimental studies have demonstrated that senses of taste and smell may be suppressed on commercial flights, the subjective wine tasting experience of non-professionals in real life testing may not be affected.
... This question is of interest especially for flight staff, passengers, and pilots. The due to to low air pressure hypobaric atmosphere in a cabin has been hypothesized to be the main contributing factor in a decreased sense of flavor [1,2], but this sense is a multisensory perception built on gustatory (tasting), olfactory (smelling), and sometimes oral-somatosensory (feeling) inputs [3]. Maier et al., e.g., demonstrated functional projections from primary taste to the primary olfactory cortex in rats [4]. ...
... Kühn effect of air pressure on butanol odor threshold and found an increased sensitivity under hyperbaric conditions and a decreased sensitivity under hypobaric conditions compared to atmospheric pressure [2]. Burdack-Freitag et al. reported higher taste and odor thresholds at low atmospheric pressure and noise compared to subsequently applied normal pressure [1]. A reduced sense of olfaction under these conditions not only contributes to a reduced perception of flavor but also could be dangerous. ...
... We tested the threshold using only one odor (n-butanol), which obviously is not representative of daily life smell perception. As Burdack-Freitag et al. reported [1], sensitivity for many other odors will decrease in a hypobaric atmosphere, and safety-related alert systems in hypobaric environments should be based on automatic sensors. The hypobaric atmosphere significantly decreased cumulative gustatory function. ...
Multidimensional food perception is based mainly on gustatory and olfactory function. Recent research has demonstrated that hypobaric pressure impairs gustatory function and that background noise or distracting auditory stimulation impairs olfactory function. Using a hypobaric chamber, the odor identification, discrimination, and thresholds as well as taste identification and threshold scores were measured in 16 healthy male volunteers under normal and hypobaric (6380 ft) conditions using clinically validated tests. In both conditions, background noise was either canceled out or replaced by white noise presentation (70 dB sound pressure level). Olfactory sensitivity for n-butanol and gustatory sensitivity were impaired in a hypobaric atmosphere. White noise did not influence the odor test results. White noise stimulation impaired sensitivity for sour and sweet but not for bitter or salty tastants. We conclude that hypobaric or noisy environments could impair gustatory and olfactory sensitivity selectively for particular tastants and odorants.
... These conditions significantly affect appetite and taste perception for foods [12][13][14]. Research has shown that under low atmospheric pressure conditions, individuals exhibit higher thresholds for salt, sugar, glutamate, and most odorants, with the exception of organic acids and bitter tastants [15]. Building on this understanding, Holthuysen et al. conducted a consumer acceptance test of airplane meals in a laboratory, a simulated airplane, and actual airplane conditions [16]. ...
... Data from two participants were excluded from further analysis due to not meeting this minimum requirement. Power spectral analysis of the EEG signals was performed using a Fast Fourier transform in various frequency bands: theta (4-8 Hz), alpha (8)(9)(10)(11)(12), and beta (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Absolute power in both quiet and noisy conditions was calculated to assess the impact of airplane background noise on baseline neural activity, using NeuroGuide 3.0.9 ...
Auditory distractions can impair the sensory evaluation of food; however, the specific impact of airplane cabin noise on the sensory perception of in-flight meals remains poorly studied. Here, we investigated the effects of airplane cabin noise on the visual processing of in-flight meal stimuli using electroencephalography (EEG) in twenty healthy male subjects. Resting-state EEG and event-related potential (ERP) responses to in-flight meal images were acquired during quiet and simulated cabin noise conditions. Participants reported mild discomfort and some loss of appetite when exposed to airplane cabin noise. The analysis of resting-state EEG showed an increase in the absolute power of theta and beta frequency bands in the left superior parietal and left frontal/right central regions under simulated cabin noise conditions, compared to quiet conditions. The ERP results showed that the amplitude of responses evoked by visual meal images in the superior parietal area was reduced in the noise condition compared to the quiet condition. Our findings suggest that airplane cabin noise disrupts the visual perception and attentional processing of in-flight food stimuli. These neural changes imply an impact on integrating sensory information, resulting in altered sensory evaluations of food during in-flight dining experiences.
... Individuals always utilize these external cues to form judgments about their surroundings, servicescapes, and organizations that they choose to frequent (Bitner, 1992;DiPietro & Campbell, 2014;Kotler, 1973;Namasivayam & Lin, 2005;Raab et al., 2013;Ryu & Jang, 2008). Many studies have evaluated the effect of environmental factors on food perception and eating behavior (Burdack-Freitag et al., 2011;Kuehn et al., 2008;Spence, 2017;. Previous studies have reported that environmental cues such as the olfactory environment (Morrin & Ratneshwar, 2000), environmental lighting (Cho et al., 2015), sound (Carvalho et al., 2016;Jacob, 2006;Lin et al., 2019), and color (Motoki et al., 2021;Piqueras-Fiszman et al., 2012) can affect the perception of food. ...
... Researchers are exploring the role of beauty from different directions and perspectives in order to maximize its effects. Previous studies related to the environment and consumer behavior have focused mainly on other aspects of the environment (Burdack-Freitag et al., 2011;Spence, 2017Spence, , p. 2020, with little attention paid to environmental aesthetic value. ...
Generally, people prefer to dine in beautiful environments. Previous studies have reported that environmental factors affect an individual's perception of food; however, little is known about the effect of environmental aesthetics on food perception. In Experiment 1, we used photographs of restaurant (1a) or non-restaurant (1b) environments with high or low aesthetic value, paired with images of foods, and participants were asked to rate the visual, olfactory, and gustatory aesthetic value of the food. Results showed significantly higher ratings for food perception in all three sensory modalities in the high aesthetic value environment, together with positive emotion and the desire to eat, compared with the low aesthetic environment. Experiment 2 extended the study to two real-world environments (one high and one low aesthetic value) and actual food consumption. The results also found higher aesthetic ratings in the olfactory and gustatory systems and greater desire to eat again in an environment with high aesthetic value than in an environment with low aesthetic value. This research also explored the mediating role of emotion in the relationship between environmental aesthetics and food perception and found a significant mediating relationship. In conclusion, environmental aesthetics play an important role in food perception, and these findings provide insights into increasing positive food perception in daily life.
... Suggestions are also drawn from the growing body of research that has addressed the role of atmospheric conditions on the perception of food in aircraft (see, e.g., Holthuysen, Vrijhof, de Wijk, & Kremer, 2016;Spence, 2017d). In particular, the loud background noise (Ozcan & Nemlioglu, 2006), lack of atmospheric humidity (Kuehn, Welsch, Zahnert, & Hummel, 2008), and reduced air pressure (Bert, 1878;Burdack-Freitag, Bullinger, Mayer, & Breuer, 2011;Maga & Lorenz, 1972) have been studied and are relevant to the situation in spacecraft, apart from the pressure aspect-the ISS is pressurized to 1 atmosphere, the same as on Earth. Therefore, studies of food flavor on aircraft provide an analogous situation from which to develop theories concerning how auditory cues might interfere with, or potentially enhance, the perception of food and drink in space. ...
... Although likely of less relevance to astronauts, it is still perhaps worth noting in passing that loud noise/music has been shown to impair people's ability to discriminate the alcohol content of drinks (Stafford, Agobiani, & Fernandes, 2013;Stafford, Fernandes, & Agobiani, 2012). Burdack-Freitag et al. (2011) reported higher taste and odor thresholds at low atmospheric pressure and noise compared to subsequently applied normal pressure. Rahne, Köppke, Nehring, Plontke, and Fischer (2018) have also recently published research in the area of background noise. ...
The intention to send a crewed mission to Mars involves a huge amount of planning to ensure a safe and successful mission. Providing adequate amounts of food for the crew is a major task, but 20 years of feeding astronauts on the International Space Station (ISS) have resulted in a good knowledge base. A crucial observation from the ISS is that astronauts typically consume only 80% of their daily calorie requirements when in space. This is despite daily exercise regimes that keep energy usage at very similar levels to those found on Earth. This calorie deficit seems to have little effect on astronauts who spend up to 12 months on the ISS, but given that a mission to Mars would take 30 to 36 months to complete, there is concern that a calorie deficit over this period may lead to adverse effects in crew members. The key question is why astronauts undereat when they have a supply of food designed to fully deliver their nutritional needs. This review focuses on evidence from astronauts that foods taste different in space, compared to on Earth. The underlying hypothesis is that conditions in space may change the perceived flavor of the food, and this flavor change may, in turn, lead to underconsumption by astronauts. The key areas investigated in this review for their potential impact on food intake are the effects of food shelf life, physiological changes, noise, air and water quality on the perception of food flavor, as well as the link between food flavor and food intake.
... Suggestions are also drawn from the growing body of research that has addressed the role of atmospheric conditions on the perception of food in aircraft (see, e.g., Holthuysen, Vrijhof, de Wijk, & Kremer, 2016;Spence, 2017d). In particular, the loud background noise (Ozcan & Nemlioglu, 2006), lack of atmospheric humidity (Kuehn, Welsch, Zahnert, & Hummel, 2008), and reduced air pressure (Bert, 1878;Burdack-Freitag, Bullinger, Mayer, & Breuer, 2011;Maga & Lorenz, 1972) have been studied and are relevant to the situation in spacecraft, apart from the pressure aspect-the ISS is pressurized to 1 atmosphere, the same as on Earth. Therefore, studies of food flavor on aircraft provide an analogous situation from which to develop theories concerning how auditory cues might interfere with, or potentially enhance, the perception of food and drink in space. ...
... Although likely of less relevance to astronauts, it is still perhaps worth noting in passing that loud noise/music has been shown to impair people's ability to discriminate the alcohol content of drinks (Stafford, Agobiani, & Fernandes, 2013;Stafford, Fernandes, & Agobiani, 2012). Burdack-Freitag et al. (2011) reported higher taste and odor thresholds at low atmospheric pressure and noise compared to subsequently applied normal pressure. Rahne, Köppke, Nehring, Plontke, and Fischer (2018) have also recently published research in the area of background noise. ...
Andrew Taylor, Jonathan Beauchamp, Loic Briand, Victor Demaria Pesce, Martina Heer, Thomas Hummel, Scott McGrane, Christian Margot, Serge Pieters, Paola Pittia and Charles Spence consider the role of food flavour in combatting under-consumption of nutrients by astronauts on the Mars expedition.
... Meanwhile, a study commissioned by Lufthansa from the Fraunhofer Institute in Germany showed that salt and sweet are most adversely affected by cabin conditions. In particular, Burdack-Freitag et al. (2011) conducted a series of carefully controlled psychophysical tests of taste and smell perception at normal and low atmospheric pressure in a simulated aircraft cabin (i.e., conducted in a 16 m section of an airplane on the ground). The high-tech. ...
... 6 Intriguingly, though, Yan and Dando׳s findings may help to explain one of the enduring mysteries about food and beverage consumption in the skies: Namely, why it is that so many people drink tomato juice or else order a Bloody Mary while up in the air (see Guilhem (2014), Jackson (2014) and ). 7 Indeed, according to one German survey of 1000 passengers conducted a few years ago, roughly one in four of us order a tomato-based drink from the flight attendants (Burdack-Freitag et al., 2011). Intriguingly, 23% of passengers reported that they never drink tomato juice while on the ground. ...
Many people complain about the taste and quality of airline food. Three of the key environmental factors that have been shown to play havoc with the passenger's ability to taste at altitude are the reduced cabin air pressure, the lack of humidity, and the loud background noise (of the plane's engines). In this review, after having outlined these and other problems that may adversely affect the tasting experience, I critically evaluate a number of the solutions that have been put forward over the years by the airlines, and others working in the field, in order to try and improve the situation. I also provide an explanation as to why it is that so many people drink tomato-based drinks while up in the skies, while rarely touching such drinks while down on the ground.
... Higher taste thresholds have been reported under lower pressure conditions (Burdack-Freitag, Bullinger, Mayer, & Breuer, 2011; Maga & Lorenz, 1972), and background noise has been reported to suppress saltiness, sweetness, and overall enjoyment of food (Spence, 2012; Woods et al., 2011 ) and hypothesized to not effect umami taste perception (Spence, Michel, & Smith, 2014). If all these influences are combined, it seems that optimizing airplane meals would ideally require extended consumer testing in real-life airplanes. ...
... This finding is somewhat surprising. Higher taste thresholds and reduced odor and taste intensity perceptions have previously been reported under lower pressure conditions (Burdack-Freitag et al., 2011 ). However, it has clearly not been possible to mimic the physiological factors that are thought to be responsible for raising taste thresholds—such as reduced atmospheric pressure, low humidity, and/ or magnetic-field exposure—in the re-created airplane context. ...
The main objective of this study was to evaluate the effect of contexts on overall liking and just‐about‐right (JAR) ratings of airplane meals. A rice dish (meal type A) and a pasta dish (meal type B) were assessed. Per meal type, two variants were produced (variant 1 and 2). Two hundred forty‐two consumers were randomly allocated to evaluate one of the four meals, first in a laboratory setting and then in a re‐created airplane environment. In addition, 222 passengers did the same assessments during an actual flight. Specific meals (A1, B1) were less liked in the laboratory than in the re‐created airplane. In general, no differentiation in overall liking occurred per meal type between the two tested variants in the laboratory, whereas these two variants were significantly differentiated in liking in the re‐created airplane and the actual airplane. Mean overall liking ratings in the re‐created airplane did not significantly differ from the mean overall liking ratings in the actual airplane. The observed JAR ratings did not differ much between the re‐created airplane and the actual airplane. In summary, the re‐created airplane as a testing location produced more similar test results to the actual airplane than the traditional laboratory.
Practical applications
Sensory consumer testing in re‐created contexts may produce results with a higher external validity than laboratory testing and therefore offer a cost‐efficient alternative to extensive sensory consumer testing in real‐life contexts.
... Food factors encompass recipe, ingredient quantity, food type, food structure [7], food color [8], serving vessel [9], and preparation methods. Finally, environmental factors consist of weather, humidity, air quality [10], temperature [11], air pressure [12], and ambient noise [13]. ...
This paper introduces a universal architecture for CONtext-aware Food and bEverage preperation System (CONFES) addressing the optimization issue in food and beverage preparation, with the aim of achieving nutritious, sustainable, and tasteful results. The concept is based on a comprehensive review of the state of the art in Machine Learning (ML) approaches for food preparation, and the latest technical developments in Cyber-Physical System (CPS). The system requirements, overarching architecture, essential components, and data model for CONFES are defined, leading to a more concrete case study. The latter describes a context-aware coffee machine as a practical implementation of the proposed architecture. The study demonstrates how CONFES can be customized to meet the specific requirements of a coffee machine, showcasing the adaptability and versatility of the overall architectural framework. The research findings contribute to the development of intelligent and context-aware systems in the domain of food and beverage preparation.
... Fewer applications of odour-emitting materials in aircraft design can improve the odour environment in the cabin and greatly increase consumer comfort. Moreover, flight altitude can also affect human taste sensation and food flavour release [33]. Meanwhile, Yao et al. [34] pointed out that individual design requirements for odour in aircraft cabins were emphasized because of passenger odour preference diversity. ...
Kansei Engineering can develop a new product by translating a customer's requirements into design, which is an ergonomic technology for product development oriented towards customer emotion. Using Kansei Engineering in aircraft design is one of the most effective means to enhance flight experience. We rely on Vosviewer software to capture the research hotspots and trends of Kansei Engineering in aircraft design, which are categorized and overviewed by a visualization network. On the one hand, the importance and methods of human sensory elements, including auditory, visual, tactile, olfactory and taste, as well as human action elements in aircraft design, are studied. It is concluded that the design of aircraft layout, materials and colour schemes has an impact on human senses and behaviour. On the other hand, not only the materials and layouts for seats, cockpits and panels are discussed, but also an argument is put forward on the materials' effective application based on Kansei Engineering. Herein, we conclude with the current application of Kansei Engineering in aircraft design and advise on future design.
... Hazardous gases are mainly classified as VOCs and odors. Several aspects affect the concentration of VOCs, such as part material, temperature [39] humidity [40] time of use [41], etc. Among these factors, the material of the parts [42] is largely responsible for the generation of hazardous gases. ...
Gas detection in enclosed cabins is a challenging concern in the industry to ensure the safety of cabin operations and personnel driving. There has been a growing development in the detection of safety in enclosed cabin operations based on volatile organic compounds, which have unique characteristics. The air pollution in closed cabins seriously affects the driver’s health, and the accuracy of the detection directly affects the operation safety of the cabin. However, until today, gas detection in enclosed cabins has relied on traditional methods that are expensive and time-consuming, and it cannot be detected in real time. This paper focuses on the potential and capability of electronic nose applications for gas detection in enclosed cabins. Since the electronic nose is a good substitute for the closed cabin, people’s attention to it has increased greatly. The characteristics of hazardous gas and warning gas in closed cabins are also discussed. In addition, this paper provides important insights into the challenges and future trends of the electronic nose, a low-cost, high-precision, and fast detection method, in more applications in closed compartments.
... The atmosphere pressure on the third day (998mbar) was the lowest in three days (the other two days were 1005mbar & 1010mbar), which may be the reason for the difference. In the study done by Burdack-Freitag et al. [35], it was also observed that odor thresholds of flavorants increase at low pressure conditions. There were few exceptions in the experiment and the odor spectrum of drinks changed differently but it was clear that atmosphere pressure influence the odor thresholds. ...
Background:
Scents may influence the perceived comfort of an environment. There are only a few studies conducted on the relationship between scent and comfort in aircraft cabin.
Objectives:
The goal of this research is to explore whether relationships between scents and perceived comfort can be found for passengers in an aircraft cabin.
Methods:
276 participants joined an experiment in a Boeing 737 fuselage. The participants were divided into nine groups and each joined a session for 60 minutes with the exposure to different scents. The effect of the odor was measured by a set of questionnaires at the beginning and at the end of the session. Results of questionnaires were analyzed regarding the effects on the completion time, of the type of scents, of the intensity of the scent and on gender.
Results:
Significant differences were found at the beginning and at the end of the experiment regarding comfort and emotion, but sometimes no relations could be established. The influence of different scents on comfort/discomfort varied and changed over time. However, in all scenarios, participant' scores on emotion decreased. Additionally, the added scents influenced the linearity between the changes in comfort and discomfort.
Conclusions:
Smell could influence the perceived comfort/discomfort of aircraft passengers over time, and different types of smells have different effects on passengers. The preferences on scents are diverse, which highlights the need for personalization in aircraft cabin design.
... Ambient pressure might also potentially play a role in odor or taste perception. For example, hypobaric pressure was shown to have a negative influence on odor thresholds [6]. Normal olfaction is required for good job performance and occupational safety in certain professions, such as mining, submarine operation, firefighting, and underwater saturation diving. ...
Introduction
Taste and smell are important for occupational performance and quality of life. Previous studies suggested that the function of these senses might be influenced by ambient pressure and noise. This knowledge would be helpful for divers, submarine crews, or mine workers. The present study aimed to investigate the effects of noise and hyperbaric pressure on olfactory and gustatory functions.
Methods
This prospective controlled study included 16 healthy male divers. Inside a hyperbaric chamber, participants performed olfactory and gustatory function tests at sea level pressure and at 2 bar pressure. The olfaction threshold, and the discrimination and identification of odorants were measured with validated ´Sniffin sticks´. Taste identification and the gustation threshold scores were examined with validated filter paper strips. Tests were performed under two conditions: noise reduction (silence) and white noise stimulation presented at 70 dB sound pressure level.
Results
The results showed that normobaric and hyperbaric ambient pressures did not significantly affect olfactory or gustatory function. Moreover, noise had no relevant impact on taste or odor sensation. The odor identification score was not influenced in hyperbaric conditions, and the odor threshold score was not influenced by ambient noise or both barometric conditions. The only taste modality affected by hyperbaric conditions was the sensitivity to salty taste, but it was not significant.
Conclusion
We concluded that hyperbaric and noisy environments have no influence on gustatory and olfactory function. From a practical point of view, the influence of pressure in moderate hyperbaric occupations should be negligible.
... And airplane travel in particular may affect other sensory functions as well. During simulated flights, healthy volunteers experienced changes in their gustatory detection thresholds [5]. As a consequence, commercial airlines have refined their in-flight meals to compensate for these flight-related sensory alterations. ...
Background
The effects of environmental changes on the somato-sensory system during long-distance air ambulance flights need to be further investigated. Changes in nociceptive capacity are conceivable in light of previous studies performed under related environmental settings. We used standardized somato-sensory testing to investigate nociception in healthy volunteers during air-ambulance flights.
Methods
Twenty-five healthy individuals were submitted to a test compilation analogous to the quantitative sensory testing battery–performed during actual air-ambulance flights. Measurements were paired around the major changes of external factors during take-off/climb and descent/landing. Bland-Altman-Plots were calculated to identify possible systemic effects.
Results
Bland-Altman-analyses suggest that the thresholds of stimulus detection and pain as well as above-threshold pain along critical waypoints of travel are not subject to systemic effects but instead demonstrate random variations.
Conclusions
We provide a novel description of a real-life experimental setup and demonstrate the general feasibility of performing somato-sensory testing during ambulance flights. No systematic effects on the nociception of healthy individuals were apparent from our data. Our findings open up the possibility of future investigations into potential effects of ambulance flights on patients suffering acute or chronic pain.
... • Providing elevated flavour sensations in scenarios where a user's sense of taste is diminished. Examples of these scenarios include elderly users (Schiffman, 1997), cancer patients undergoing che- motherapy (Comeau, Epstein, & Migas, 2001) and passengers on airplanes (Burdack-Freitag, Bullinger, Mayer, & Breuer, 2011). ...
In recent years there has been a growing interest in the potential benefits and new applications that may be afforded by incorporating digital flavour augmentation technologies into traditional eating and drinking experiences. Although many studies have shown how controlled olfactory, visual and auditory cues can impact flavour experiences, there has been a relatively small amount of work that has investigated the utilisation of digital gustatory (taste) augmentation in the same context. Hence, we have created two utensils, a pair of chopsticks and a soup bowl, that apply controlled electrical pulses to the tip of the tongue during consumption in order to augment flavours through electrical stimulation. As such, in this paper we present a study that aimed to evaluate the impact of electric taste augmentation on two types of eating experiences: consuming mashed potato and miso soup. Based on this study, our findings demonstrate that 1) significant increases in perceived saltiness and sourness can be achieved when consuming unsalted mashed potato and 2) significantly higher ratings of sourness can be achieved when consuming diluted miso soup.
... The chamber contained 7 seats. Participants seated in the pressure chamber for approximately one hour to experience a simulated airplane flight by altering the pressure and air composition similar to what occurs during a real flight [26]. The pressure switched from the atmospheric pressure observed at ground level, to the pressure value present at an altitude of 2438 m, and returned to the ground level when the time was over. ...
Background
Airplane Headache (AH) occurs during flights and often appears as an intense, short lasting headache during take-off or landing. Reports are limited on pathological mechanisms underlying the occurrence of this headache. Proper diagnosis and treatments would benefit from identification of potential pathways involved in AH pathogenesis. This study aimed at providing a simulated airplane headache condition as a proxy towards identification of its underlying mechanisms. Methods
Fourteen participants including 7 volunteers suffering from AH and 7 healthy matched controls were recruited after meeting the diagnostic and safety criteria based on an approved study protocol. Simulation of AH was achieved by entering a pressure chamber with similar characteristics of an airplane flight. Selected potential biomarkers including salivary prostaglandin E2 (PGE2), cortisol, facial thermo-images, blood pressure, pulse, and saturation pulse oxygen (SPO) were defined and values were collected before, during and after flight simulation in the pressure chamber. Salivary samples were analyzed with ELISA techniques, while data analysis and statistical tests were handled with SPSS version 22.0. ResultsAll participants in the AH-group experienced a headache attack similar to AH experience during flight. The non-AH-group did not experience any headaches. Our data showed that the values for PGE2, cortisol and SPO were significantly different in the AH-group in comparison with the non-AH-group during the flight simulation in the pressure chamber. Conclusion
The pressure chamber proved useful not only to provoke AH-like attack but also to study potential biomarkers for AH in this study. PGE2, and cortisol levels together with SPO presented dysregulation during the simulated AH-attack in affected individuals compared with healthy controls. Based on these findings we propose to use pressure chamber as a model to induce AH, and thus assess new potential biomarkers for AH in future studies.
Water vapour in the air is an essential element that directly affects all animate and inanimate constituents of the planet. It is a fundamental constituent in all interactions that characterize life and planetary systems. Water vapour in the air is distinctly associated with the functioning of the human sense organs. All five senses, i.e. smell, touch, sight, sound and taste respond to water vapour in the air. The sensory mechanisms determine a human being's physiological and psychological balance, which is the foundation of wellness, relevant on a planetary scale. However, the sensory mechanisms associated with water vapour in the built environment have not been discerned holistically, particularly its role in human wellness. The present article reviews sensory perceptions and responses attributed to humidity/water vapour in the built environment and examines its role in promoting human wellness, drawing insights from diverse interdisciplinary disciplines.
This chapter has the important function to describe the other primary headache disorders like thunderclap headache, exercise headache and sexual headache and other primary forms, but above all as forms that must alert the clinician because they can also be signs of secondary forms. The educational target is clinicians that, observing very violent and unusual forms of headache, can immediately orient themselves in the definition of primary or secondary forms, since errors in this diagnostic process could be life-threatening.
1. Einführung Die Atmosphäre der Erde bietet nur auf Meeresniveau und auch nicht in allen geografischen Lagen akzeptable Lebensbedingungen für den Menschen. Schon ab einer Höhe von 1000 – 1500 Meter über NN werden die ersten Einschränkungen der Leistungsfähigkeit erkennbar: Obwohl die Zusammensetzung der Atmosphäre gleich bleibt -sie enthält ca. 21% des für den Menschen lebenswichtigen Sauerstoffs – sinkt dessen Partialdruck mit abnehmendem atmosphärischen Druck ab, der Organismus wird nicht mehr ausreichend mit Sauerstoff versorgt. In den heute üblichen Reiseflughöhen von 40000 ft und mehr für den kommerziellen Passagiertransport wird der Druck so gering, dass ein Überleben des Menschen ohne besondere technische Hilfsmittel nicht möglich ist; bei Lösung des Problems mittels einer bedruckten Flugzeugkabine muss auch das durch die Insassen produzierte Kohlendioxid berücksichtigt werden. Neben dem äußeren Druck nimmt mit steigender Höhe auch die Temperatur kontinuierlich ab, sodass in Reiseflughöhe arktische Außentemperaturen herrschen, mit der Notwendigkeit, die Kabine entsprechend zu heizen; auch die Luftfeuchte muss in die zu regelnden Parameter einbezogen werden. Für Notfälle müssen Alternativsysteme vorgesehen werden. 2. Kabinenatmosphäre Eine primäre Anforderung an die Flugzeugkabine besteht also in der Bereitstellung von geeigneten klimatischen Verhältnissen hinsichtlich Druck, Temperatur und Gaszusammensetzung; je größer die geforderte Ähnlichkeit zur (optimalen) natürlichen Umgebung des Menschen, desto höher der technische Aufwand. Bei der üblichen Auslegung der Kabine als offenes System steht zwar in unbegrenzter Menge Frischluft aus der umgebenden Atmosphäre zur Verfügung, aufgrund der äußeren Bedingungen kommt es aber zum Konflikt zwischen einzelnen klimatischen Parametern. Unter heute gültigen Bestimmungen wird ein Kabinendruck entsprechend 8000 ft als ausreichend für eine zufriedenstellende Sauerstoffversorgung angesehen. Zwar werden einzelne Komponenten des mentalen Instrumentariums in diesem Bereich schon nachweisbar beeinträchtigt – dies ist natürlich besonders für die Cockpit-Crew von Bedeutung -, dennoch machen sich spürbare Beeinträchtigungen beim Gesunden nur unter stärkerer körperlicher Belastung bemerkbar. Einige Autoren weisen allerdings darauf hin, dass die heutige Passagier-Population einen nicht unerheblichen Anteil von älteren Menschen mit vorbestehenden Erkrankungen des Atem-und Kreislaufsystems aufweist, sodass hier schon innerhalb der Richtwerte mit Sauerstoffmangel-Problemen gerechnet werden muss.
Odorant deposition in the nasal and olfactory mucosas is dependent on a number of factors including local air/odorant flow distribution patterns, odorant mucosal solubility and odorant diffusive transport in the mucosa. Although many of these factors are difficult to measure, mucosal solubility in the bullfrog mucus has been experimentally determined for a few odorants. In the present study an experimental procedure was combined with computational fluid dynamic (CFD) techniques to further describe some of the factors that govern odorant mucosal deposition. The fraction of odorant absorbed by the nasal mucosa (eta) was experimentally determined for a number of odorants by measuring the concentration drop between odorant 'blown' into one nostril and that exiting the contralateral nostril while the subject performed a velopharyngeal closure. Odorant concentrations were measured with a photoionization detector. Odorants were delivered to the nostrils at flow rates of 3.33 and 10 l/min. The velopharyngeal closure nasal air/odorant flows were then simulated using CFD techniques in a 3-D anatomically accurate human nose modeland the mucosal odorant uptake was numerically calculated. The comparison between the numerical simulations and the experimental results lead to an estimation of the human mucosal odorant solubility and the mucosal effective diffusive transport resistance. The results of the study suggest that the increase in diffusive resistance of the mucosal layer over that of a thin layer of water seemed to be general and non-odorant-specific; however, the mucosa solubility was odorant specific and usually followed the trend that odorants with lower water solubility were more soluble in the mucosa than would be predicted from water solubility alone. The ability of this approach to model odorant movement in the nasal cavity was evaluated by comparison of the model output with known values of odorant mucosa solubility.
Long-distance flights can cause a number of clinical problems in both passengers and crewmembers. Jet lag as well as mild hypoxia resulting from incomplete cabin pressurization could contribute to these problems. The objective of this study was to assess, using a chronobiological approach, the clinical impact of diurnal hypobaric, hypoxic exposure on fatigue and other common symptoms encountered during high-altitude exposure and to measure changes in blood chemistry (i.e., plasma creatinine, urea, uric acid, sodium, calcium, phosphorus, glycemia, and lipids). Fourteen healthy, diurnally active (from 07:00 to 23:00 h) male volunteers, aged 23 to 39 yrs, spent 8.5 h in a hypobaric chamber (08:00 to 16:30 h), at a simulated altitude of 8,000 ft (2,438 m). This was followed by an additional 8.5 h of study four weeks later at a simulated altitude of 12,000 ft (3,658 m). Clinical data were collected every 2 h between 08:00 and 18:00 h, and biological variables were assayed every 2 h over two (control and hypoxic-exposure) 24 h cycles. Clinical symptoms were more frequent with the 12,000 ft exposure. Wide interindividual variability was observed in the clinical tolerance to prolonged hypobaric hypoxia. The 24 h profiles of most biochemical variables were significantly altered at each altitude, with changes in mean plasma levels and a tendency toward phase delay, except for uric acid, which showed a phase advance. Changes in appetite mainly occurred with the simulated 12,000 ft exposure and may have been associated with changes in the postprandial glycemia profile. Finally, though the observed biochemical changes were significant, their clinical relevance must be clarified in studies involving actual long-distance flights.
Though the solubility of an individual gas in water forms, generally, a part of its chemical history, yet this property has been overlooked, in the examination of several species of the class of aëriform substances. The carbonic acid, indeed, is the only gas whose relation to water has been an object of much attention; and, at a very early period of its history, Mr. Cavendish, in the course of inquiries, the results of which were the groundwork of the most important subsequent discoveries, ascertained, with peculiar care, the proportion of carbonic acid gas condensible in water, at the temperature of 55º of Fahrenheit. Dr. Priestley also, about the same period, directed his attention to the saturation of water with fixed air, and contrived a simple and effectual mode of obtaining this impregnation. His apparatus, afterwards, gave way to the more manageable one of Dr. Nooth; and this, in its turn, has been superseded by the improved mode of condensing, into water, many times its bulk of various gases, invented and practised by several chemical artists, (as well as by myself,) both in this country and abroad. The influence of pressure, in accomplishing this strong impregnation, was first, I believe, suggested by Dr. Priestley. “In an exhausted receiver,” that most ingenious philosopher observes, “Pyrmont water will actually boil, by the copious “discharge of its air; and I do not doubt, therefore, that by “means of a condensing engine, water might be much more “highly impregnated with the virtues of the Pyrmont “spring.”
The olfactory properties, a 'strength', character, and odor threshold values of the series of chlorinated anisoles has been studied. 2,3,4,6 2,4,6 2,3,6 and 2,6 chloroanisole are shown to have a strongly musty odour and low thresholds, whereas the other compounds are less musty and weaker. These chemicals with a 2,6 chlorination are shown to have a pronounced fatiguing effect. (22 references).
Volatile constituents of nectarines (Prunus persica L., Batsch var. nucipersica Schneid) were isolated by means of liquid-liquid extraction with ether and analyzed by capillary gas chromatography and gas chromatography-mass spectrometry. Aroma patterns (10 lactones, 8 C6 aldehydes and alcohols, 8 terpenoids, 3 esters, 4 other compounds) were identified and (semi)quantified in four cultivars. Besides C6 components a series of saturated and unsaturated γ- and δ-lactones ranging from chain length C6 to C12, with concentration maxima for γ- and δ-decalactone, were a major class of constituents. By determination of odor thresholds and calculation of odor units the significance of lactones and other volatiles (e.g., linalool) to the aroma of nectarines was investigated.
Application of an aroma extract dilution analysis to the flavour concentrate of a pale lager beer revealed 33 primary odorants (FD factors ranging over 16 to 1024) among which 3-methylbutanol, 2-phenylethanol, 4-vinyl-2-methoxyphenol, 3- and 2-methylbutanoic acid, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol) and butanoic acid showed the highest FD factors. With a somewhat lower FD factor ethyl butanoate, 4,5-dimethyl-3-hydroxy-2(5H)-furanone (sotolone), ethyl hexanoate, hexanoic acid and (E)-β-damascenone contributed to the overall flavour. Compared to the pale lager beer, the odour activity value (OAV; ratio of concentration to odour threshold) of furaneol in a dark lager beer and of 4-vinyl-2-methoxyphenol in a wheat beer, was significantly higher. Sensory experiments corroborated that these odorants were important contributors to the overall flavour of the dark lager and the wheat beer, respectively. In two alcohol-free beers the OAVs of eight of the most important odorants were markedly lower. After storage of a pale lager beer (14 d; 40° C), which had been spiked with oxygen, the FD factors of most of the primary odorants of the fresh beer remained unchanged. On the other hand, phenylacetaldehyde, 3-methyl-3-mercaptobutylformate (catty,Ribes odour) and an unknown compound with a sweet, aniseed-like note appeared as additional important odorants in the stored sample.
The odour tresholds of 24 aroma compounds in Senga Sengana strawberries were determined using duo-trio tests. The threshold values were compared with concentrations in the fruit, and the compounds divided into groups according to their aroma values (concentration/threshold). The most important compounds were ethyl butanoate, ethyl hexanoate and 2,5-dimethyl-4-hydroxy-3(2H)-furanone, but even compounds in concentrations below the threshold values had some influence on the odour.Die Geruchsschwellen von 24 Aromastoffen der Senga Sengana Erdbeeren wurden mit Duo-Trio-Tests bestimmt. Die Werte wurden mit den Konzentrationen der Aromastoffe in der Frucht verglichen, und die Aromastoffe wurden in Gruppen nach den Aromawerten (Konzentration/Schwelle) eingeteilt. Die wichtigsten Komponenten waren Ethylbutanoat, Ethylhexanoat und 2,5-dimethyl-4-hydroxy-3(2H)-furanon, aber auch Komponenten in Konzentrationen unter den Schwellenwerten hatten Einflu auf den Geruch.
After orbital flight for 19–22 days on the satellites Kosmos-605 and Kosmos-782 erythropoiesis of rats was inhibited and the morphology of their megakaryocytes was modified. These changes disappeared by the 25th–27th day after the flight.
Two strawberry (Fragaria × ananassa Duch.) cultivars differing in their sensitivity to NaCl stress, cv. Elsanta (sensitive) and cv. Korona (less sensitive), were cultivated under 0, 40 and 80 mmol NaCl/l for two months during flowering and fruiting until final fruit harvest. Modifications of sensory quality parameters and selected chemical properties of the non-climacteric fruit were evaluated. Generally, NaCl salinity decreased quality of strawberry fruit, especially in cv. Elsanta. Fruits of stressed plants contained lower amounts of sugars, organic acids and soluble solids, were less sweet and did not meet consumers’ requirements. Overall appearance of fruits decreased significantly. The reduced acceptance to consumers was closely correlated with the decline of sugar contents, especially sucrose content, as well as with the increase of organic acids, such as acetic acid. Sensory changes were revised on the basis of a dose to threshold relationship. Decreasing contributions of sugars to taste and a rising importance of sodium, acetic and citric acids as the most taste-relevant compounds were the main causes of the limited acceptance of salt-stressed fruits.
To provide further insight into the relationship between the structure of hydrocolloid solutions and gels and perception of taste and flavour, solutions of gelatin and locust bean gum (LBG), and gels prepared from mixtures of (a) high acetyl and low acetyl and gellan (b) carrageenan and LBG were studied. Both the solutions contained sodium chloride and the gels were flavoured with ethyl butyrate.The gels were classified from rheological measurements into three categories: strong/brittle, intermediate and soft/elastic. Volatile release was measured by monitoring nose space volatile concentration during consumption using atmospheric pressure chemical ionisation-mass spectrometry (APCI–MS). In addition headspace measurements were performed with APCI–MS. The headspace concentrations did not exhibit significant differences between the gels system but the release of ethyl butyrate in-nose was affected by the matrix, showing a higher intensity for the more brittle gels containing high levels of low acetyl gellan. The release of Na+ following a two-bite compression was monitored by the use of an ion-specific electrode. The more brittle gels containing high levels of low acetyl gellan and high amount of κ-carrageenan exhibited significantly higher release of Na+. Strain at break correlated inversely with salt release (r2=−0.87) and more weakly inversely with the maximum nose space volatile concentration (r2=−0.55).When LBG solutions containing salt were mixed with distilled water it was found that both salt release and mixing efficiency decreased at polysaccharide concentrations above c*. In contrast gelatin solutions, measured at 50 °C, maintained good salt release and mixing behaviour at high concentrations.It is concluded that the intensity of flavour perception in hydrocolloid solutions and gels is dominated by the release of the tastant. In solutions this is favoured by good mixing behaviour between the hydrocolloid solution and saliva and in gels by a low strain at break. A gelatin replacement should not only show melt in the mouth behaviour but good mixing between the gelatin melt and the saliva.
The release of strawberry flavour compounds from pectin gels and gelatin gels was evaluated by instrumental and sensory analysis. Three gel textures were established based on Young’s modulus of elasticity (E) for each gel. The E of the low, medium and high rigidity gelatine and pectin gels was 181, 300 and 493 N m−2, respectively. Air/gel partition coefficients were determined by static headspace analysis. In-nose/proton transfer reaction-mass spectrometry analysis produced temporal release profiles. Sensory analysis was conducted to assess perceived odour, thickness, strawberry flavour and sweetness using magnitude estimation. The type of hydrocolloid affected static and in-nose compound concentrations significantly. The pectin gels showed lower air/gel partition coefficients than the gelatin gels, but increased flavour release. Increased gel rigidity resulted in lower air/gel partition coefficients; higher maximum concentrations of volatiles and lower release rates during in-nose analysis; decreased perception of odour, strawberry flavour and sweetness; and higher intensity ratings for thickness in sensory analysis. Consequently, both type of hydrocolloid and rigidity of the sample greatly affected flavour release and perception.
The non-volatile taste active compounds, including soluble sugars, succinic acid, free amino acids and flavour 5′-nucleotides in the meat of Chinese mitten crab (Eriocheir sinensis) were analyzed, and their taste impacts were evaluated by taste active values (TAVs) and equivalent umami concentration (EUC) methods. The total free amino acid content of crab meat was 20.9 mg/g. Arginine, glycine and alanine were the major free amino acids, accounting for more than 70% of the total free amino acids. 5′-Adenosine monophosphate (AMP) was the main flavour 5′-nucleotide (75.3 mg/100 g), followed by 5′-inosine monophosphate (IMP) (34.4 mg/100 g) and 5′-guanosine monophosphate (GMP) (2.3 mg/100 g). Arginine, glycine, alanine, glutamic acid, IMP and AMP were of high TAV (greater than one), and they had strong taste impacts on the crab meat flavour. Glycine and alanine contributed to the major sweet taste, while glutamic acid, IMP and AMP contributed to the strong umami taste. As the TAVs of soluble sugar, succinic acid and bitter free amino acids were lower than one, thus those compounds are likely to have insignificant impact on the taste of the crab meat. The EUC was 4.2 g MSG/100 g crab meat, which meant that the umami taste of the crab meat was very intense.
The present study evaluates the contribution of the receptor cell compartment to the total mucosal odorant uptake. Using radioactive odorants, partition coefficients for normal bullfrog olfactory mucosa were compared to the partition coefficients from mucosa in which the receptor cells had been removed by cutting one of the olfactory nerves and allowing two weeks for complete degeneration. For the more water-soluble odorants (butanol and isobutyric acid), both sides sorbed the same amount of odorant, suggesting that the mucosal uptake mostly reflects uptake by the water in the mucosa. For the less water soluble odorants (octane and amyl acetate), the uncut side did sorb significantly more odorant than the cut side.
This study was carried out to evaluate the effect of continuous exposure to hypobaric hypoxia on the feeding behavior and taste responses of rats, under simulated conditions of a high altitude (HA) of 7,620 m for 21 h a day and consecutively for 18 d, which more closely resembles actual field conditions. Their food, water intake and body weight were recorded daily, and blood sugar was estimated once a week. All the parameters were recorded for a period of 18 d each, before, during, and after exposure to simulated HA. The results show a decrease in daily food and water intake and body weight, and mild hypoglycemia during hypoxic exposure. Single-bottle and two-bottle tests showed a preference for sweet solutions over water, citric acid, sodium chloride, and quinine sulfate during exposure. The two-bottle test showed a preference for glucose over calorically-inert saccharine. The continuous exposure in this study produced qualitatively similar but quantitatively accentuated results as compared to intermittent 6 h exposure contiguously for 21 d. High-altitude stress appears to influence food intake such that sensory cues assume greater significance during feeding behavior.
We hypothesized that progressive loss of body mass during high-altitude sojourns is largely caused by decreased food intake, possibly due to hypobaric hypoxia. Therefore we assessed the effect of long-term hypobaric hypoxia per se on appetite in eight men who were exposed to a 31-day simulated stay at several altitudes up to the peak of Mt. Everest (8,848 m). Palatable food was provided ad libitum, and stresses such as cold exposure and exercise were avoided. At each altitude, body mass, energy, and macronutrient intake were measured; attitude toward eating and appetite profiles during and between meals were assessed by using questionnaires. Body mass reduction of an average of 5 +/- 2 kg was mainly due to a reduction in energy intake of 4.2 +/- 2 MJ/day (P < 0.01). At 5,000- and 6,000-m altitudes, subjects had hardly any acute mountain sickness symptoms and meal size reductions (P < 0.01) were related to a more rapid increase in satiety (P < 0.01). Meal frequency was increased from 4 +/- 1 to 7 +/- 1 eating occasions per day (P < 0. 01). At 7,000 m, when acute mountain sickness symptoms were present, uncoupling between hunger and desire to eat occurred and prevented a food intake necessary to meet energy balance requirements. On recovery, body mass was restored up to 63% after 4 days; this suggests physiological fluid retention with the return to sea level. We conclude that exposure to hypobaric hypoxia per se appears to be associated with a change in the attitude toward eating and with a decreased appetite and food intake.
The airline pilot operates within an environment that consists of circadian dysrhythmia, reduced atmospheric pressure, mild hypoxia, low humidity, and exposure to sound, vibration, cosmic-radiation, and magnetic-field exposure. These occupational exposures present physiological challenges to the long term health of the airline pilot. In particular, exposure to cosmic radiation and its carcinogenic potential have recently received considerable attention. Given the complexity of the environment and possible synergistic exposures, there is an immediate requirement for comprehensive research into both cosmic-radiation and magnetic-field exposures in airline pilots. In response, the Airline Pilots Association International in conjunction with the Medical University of South Carolina (Department of Biometry and Epidemiology) has initiated an extensive research program into these occupational exposures. These investigations include ground based calculations, flight-dose estimates, epidemiological survey and exposure assessment, and biological marker analysis.
The effect of space flight and microgravity on the chemical senses is reviewed. Skylab-4 and Soyuz 30-31 studies revealed changes in taste thresholds while no effect was found in a Canadian investigation (41-G) and conflicting results were obtained on another Soyuz mission. Two simulated microgravity studies found no effect on taste or smell sensitivity; while 5 other studies found an effect. Microgravity induces physiological changes including an upward shift of body fluids toward the head, which may lead to an attenuation of the olfactory component in the flavor of foods. Chemosensory changes may also relate to space sickness, Shuttle atmosphere, stress, radiation, and psychological factors.
The release of isoamyl acetate from starch-based matrices was studied on the basis of a cumulative dynamic headspace analysis. Two corn starches were compared, which are known to yield pastes and gels differing in their structures and properties. These properties were assessed by viscometry and viscoelastic measurements. Aroma release was discussed as a function of the structure and texture parameters of the matrix. The release curves obtained from water and from the various starch-based matrices at 25 degrees C showed similar patterns but differed in their initial slopes and in the final plateau values. The lowest initial slopes were obtained for the normal starch dispersions that formed gels due to amylose gelation. The aroma compound was entirely released from water and from the waxy starch pastes. A significant amount of isoamyl acetate remained trapped in the normal starch dispersions.
This review discusses the relationship of altitude to barometric pressure, effects of the hypoxia of high altitude, acclimatization to high altitude, improving working efficiency at high altitude, physiologic changes at extreme altitudes, and high-altitude diseases.
Sensory-guided decomposition of roasted cocoa nibs revealed that, besides theobromine and caffeine, a series of bitter-tasting 2,5-diketopiperazines and flavan-3-ols were the key inducers of the bitter taste as well as the astringent mouthfeel imparted upon consumption of roasted cocoa. In addition, a number of polyphenol glycopyranosides as well as a series of N-phenylpropenoyl-l-amino acids have been identified as key astringent compounds of roasted cocoa. In the present investigation, a total of 84 putative taste compounds were quantified in roasted cocoa beans and then rated for the taste contribution on the basis of dose-over-threshold (DoT) factors to bridge the gap between pure structural chemistry and human taste perception. To verify these quantitative results, an aqueous taste reconstitute was prepared by blending aqueous solutions of the individual taste compounds in their "natural" concentrations. Sensory analyses revealed that the taste profile of this artificial cocktail was very close to the taste profile of an aqueous suspension of roasted cocoa nibs. To further narrow down the number of key taste compounds, finally, taste omission experiments and human dose/response functions were performed, demonstrating that the bitter-tasting alkaloids theobromine and caffeine, seven bitter-tasting diketopiperazines, seven bitter- and astringent-tasting flavan-3-ols, six puckering astringent N-phenylpropenoyl-l-amino acids, four velvety astringent flavonol glycosides, gamma-aminobutyric acid, beta-aminoisobutyric acid, and six organic acids are the key organoleptics of the roasted cocoa nibs.
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