Astronauts often say that eating in space takes away all the fun. Food that tastes delicious on Earth can become bland and boring in orbit.
In fact, despite carefully formulated diets, astronauts often struggle to find enough food to meet their energy needs.
We conducted some experiments on Earth, using virtual reality (VR) and a simulated spacecraft environment to study how space travel might affect a person’s sense of smell and experience of food.
We found that some smells seem much more intense in a space-like environment – and that earlier theories about how zero gravity affects the body may not be the whole story. Our results, published in the International Journal of Food Science and Technology, could help design future space menus.
Eating is a complicated experience
Eating is a multi-sensory experience that involves sight, smell, taste, hearing, and touch.
To enjoy the taste of food – say, when biting into an apple – we need a combination of many senses, including taste (sweet, sour), smell (the complex combination of apple aromas), texture (crispness), color (green, red) and touch (firmness). If any of these senses is dulled, our enjoyment of food will not be the same.
The experience of dining in space is very different from what we experience here on Earth.
One possible explanation for why astronauts experience taste differently is the lack of gravity. Without gravity, bodily fluids do not pull toward the feet but instead move toward the head, causing a sensation similar to a stuffy nose. If you’ve ever had a cold, you know how difficult it is to taste and enjoy food without smell.
But could there be other reasons for this?
Importance of environment
In space, the environment is unfamiliar and constantly monotonous. Could this change our perception of food?
Context plays a huge role in the eating experience. Studies have shown that eating the same meal in different places can lead to different opinions about the food. Think about enjoying a picnic sandwich in a beautiful park or eating the same sandwich quickly at your work desk.
The spacecraft is a closed and confined environment, an airtight container in which you are surrounded by wires and equipment and there is no boundary between work and personal space. Imagine living in a pandemic-level lockdown for several years with limited food and essentials (and a constantly stuffed nose).
A taste-test study compared airline food in three conditions: a classic sensory laboratory environment (quiet, closed or semi-closed room – like a voting booth), a semi-realistic aircraft environment created in the laboratory using aircraft accessories, and an actual flight.
Passengers in the simulated plane environment enjoyed their meals almost as much as passengers on the real flight. (Both liked it less than people in the lab environment.) This shows that the plane environment has a significant effect on the enjoyment of food.
Bringing space down to earth
Research involving humans in space is very challenging. Space missions typically involve a maximum of six or seven crew members, which limits the sample size for experiments and the power to predict results.
Furthermore, for food research, each individual has unique sensory experiences and responses to them. This makes it challenging to understand how different individuals perceive odors in space, let alone food aromas.
So we decided to recreate space on Earth. Using VR, we simulated the environment of the International Space Station.
The VR setup allows us to obtain data about participants’ feelings about food stimuli “in the moment,” rather than waiting for them to take off the headset and then asking them questions. VR is an important training environment for astronauts because it has an unmatched ability to create a realistic sense of presence, which is crucial for studying what it’s like to be in spaceflight.
Our study is the first to include a significant sample size (54 people) to capture variations in individuals’ individual experiences of smell and taste in artificially isolated environments.
In our study comparing everyday scents, some scents were perceived differently in the virtual International Space Station environment than in the partitioned booth environment.
The molecular magic of fragrance
Fragrances are complex mixtures of molecules with unique chemical structures that influence their interaction with olfactory receptors located in the nose, producing distinctive odors.
Our study shows that only specific scent compounds are perceived differently in a space-like environment. We found that sweet-smelling molecules are perceived more strongly.
Vanilla and almond, which contain the sweet, almond or cherry scent compound benzaldehyde, smelled stronger in our VR space station than in the control environment. In contrast, there was no difference in the perception of the lemon scent.
This knowledge can be used in designing space food. For example, sweet scents could be used as flavor enhancers or additives to bring out other flavors and add depth.
It’s important to understand how these aroma compounds interact with each other, and to find the right concentration level. And of course, no single flavor will suit everyone’s taste.
Worldly implications
A better understanding of how smells are perceived in environments such as space could inspire ways to create personalized diets based on each astronaut’s unique sensory experiences and preferences. By customizing the aroma of food, we could encourage astronauts not only to eat more, but also to enjoy food more.
These solutions could also help people living in isolated or confined environments on Earth, such as nursing home residents, individuals on military deployment, and submarine crews.
,Author: Julia Low, Senior Lecturer in Nutrition and Food (Sensory Science), RMIT University; Grace Loke Mei Eng, PhD Candidate in Food Science, RMIT University; Ian Peek, Digital Solutions Architect, RMIT University; Jayani Chanderpal, Associate Professor, RMIT University, and Lisa Newman, Lecturer in Nutrition, RMIT University)
(Disclosure statement: The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment)
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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