By: Ty Wagoner

“So what’s the deal with airplane food?” Mediocre comedy routines have posed this question for decades, but there may be some scientific truth to that comedy shtick. It turns out that flying high at 32,000 feet does a number on your taste buds, so it may not be just a question of food quality, but also how your brain perceives flavor! And consequently, a lot more thought goes into what you eat and drink at 32,000 feet than you may realize.

Let’s first have a brief recap on what tastes and flavors are. Humans have five basic tastes (with some discussion/contention on fat as a potential sixth taste) associated with sweet, salt, sour, bitter, and umami. We detect these tastes when specific molecules bind to receptor sites located within papillae on your tongue, sending a response to your brain. Flavors, on the other hand, are a considerably more complex combination of taste and smell. As you chew your food, volatile compounds are released and travel through the back of your mouth to the nasal cavity. Here, the compounds bind with olfactory receptors and induce a perception of flavor in your brain (in other words, flavor is all in your head).

Image modified from https://en.wikipedia.org/wiki/Olfactory_nerve

Well, what does this physiology lesson have to do with airline food? It turns out that both tastes and flavors are modified under the environmental conditions of an airline cabin. There are two conditions that work against your sniffer – low pressure (the equivalent of 2–2.5 km elevation) and very low humidity (often < 12%). These conditions dry out your nasal cavity and make it more difficult for compounds to bind to receptors and be detected (Kuehn et al., 2008). In other words, it’s like you have a cold!

Perhaps more surprisingly, flight conditions even influence the perception of basic tastes! After spending 3 weeks at 3.5 km altitude, participants in one study had a harder time detecting sweetness and saltiness, whereas sourness and bitterness were more pronounced (Singh et al., 1997); this is essentially the opposite of what we want. The German airline Lufthansa took this a step further and mimicked the flight conditions of a commercial jet, reporting that the combination of humidity, vibration, and low pressure reduced salt perception by 20–30% and sweetness by 15–20%.
 

Don’t worry, it’s not all bad news. There is a beacon of hope for frequent flyers – tomato juice! The enigma of airplane tomato juice is well-known (according to Lufthansa, 23% of people that drink tomato juice on a flight would never touch the stuff on terra firma). So why is tomato juice so delicious during a flight? Food scientists at Cornell University tackled the problem, and the results may surprise you. Participants in the study were exposed to 80–85 dB of white noise meant to mimic the cacophony of a normal flight (Yan & Dando, 2015). Not only did noise reduce perception of sweetness and saltiness, but it enhanced the perception of umami (which is perfect for glutamate-packed foods like tomatoes!). So if you’re looking for the perfect libation on your next flight, skip the soda, crank up your headphones, and relax with a can of super fruit juice.

References:

Kuehn, M., Welsch, H., Zahnert, T., & Hummel, T. (2008). Changes of pressure and humidity affect olfactory function. Eur Arch Otorhinolaryngol, 265(3): 299-302.

Singh, S.B., Sharma, A., Yadav, D.K., Verma, S.S., Srivastava, D.N., Sharma, K.N., & Selvamurthy, W. (1997). High altitude effects on human taste intensity and hedonics. Aviat Space Environ Med, 68(12): 1123-1128.

Yan, K., & Dando, R. (2015). A crossmodal role for audition in taste perception. J Exp Psychol Hum Percept Perform, 41(3): 590-596.

A feast for research. Fraunhofer IBP.. Retrieved January 15, 2016, from http://www.ibp.fraunhofer.de/en/Press/Research_in_focus/Archives/A_feast_for_research.html