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

Does ambient noise or hypobaric atmosphere influence olfactory and gustatory function?

“…Also in line with earlier findings [ 2 ], we observed no effect of pressure on odor discrimination, but the gustatory score was significantly reduced. As with previous results [ 1 ], the higher taste thresholds for salty drove the gustatory score reduction. The lower (better) threshold for sweet, however, is discordant with earlier findings [ 1 ], whereas the threshold constancy of sour and bitter tastants is in line with those results.…”

“…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.…”

“…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 et al systematically investigated the 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.…”

Nociception testing during fixed-wing ambulance flights. An interventional pilot study on the effects of flight-related environmental changes on the nociception of healthy volunteers

“…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.…”