When you're on a plane, you may feel like an in-flight meal doesn't taste good. In fact, the poor taste of the in-flight meal is not entirely the problem of the food itself. What is the difference between eating the same meal on the ground and eating it in the cabin of an aircraft at high altitude?

In 2010, Lufthansa discovered that passengers consume much more tomato juice on board than on the ground. Why did the seemingly ordinary tomato juice become the darling of cabin drinks after "going to heaven"? To find out, Lufthansa hired a well-known German research institute to conduct a trial. The researchers brought a group of people into an airplane simulator on the ground, mimicking the high-altitude environment, cabin pressure, engine noise, and even the blue sky and white clouds outside the window. As a result, the participants agreed that the taste of tomato juice in the simulated cabin had improved.

看到這裡，相信您一定有所察覺：高空飛行環境就是影響我們對味道感知能力的最大肇因。原來，飛機進入平飛狀態，高空中的氣壓會明顯低於標準大氣壓。雖然機艙內會進行加壓，但仍無法達到與地面一致的狀態。而且缺少濕度這個“調味劑”，我們感官的“鈍感力”會明顯增強。在約3萬英尺的高空，機艙中的濕度只有不到12%，比多數沙漠還要乾燥。這樣的環境會影響鼻黏液分泌，當鼻腔內很乾燥時，大腦檢測氣味信號的效率就會降低，從而影響我們的嗅覺。

In addition to not being able to smell the food as it should be, the cabin environment can also make it impossible for passengers to eat the original taste of the food. Studies have shown that eating in a low-pressure, dry cabin reduces people's perception of salt by 20%~0% and sugar by 0%~0%.

It is important to know that people's perception of taste is not only based on taste, but also by the combined influence of smell, touch, sight and hearing. Although the tongue can only taste 5 flavors, the sense of smell can distinguish hundreds of gas molecules, so the smell of food brings a rich sensory variety. For example, when a person has a cold, he or she always feels tasteless when he eats because his sense of smell has been weakened. The temperature and touch of the food also make up the taste, and the food in the mouth activates the sensory cells in the mouth, so we can perceive the difference between the texture of a cream cake and a crispy potato chip. In addition, it is often assumed that desserts on a white plate are sweeter than those on a black plate, and that potato chips are crispier with your mouth open than with your mouth closed, suggesting that sight and hearing also play an integral role in the perception of taste.

飛機上的雜訊也會影響旅客對甜味的感知。美國康奈爾大學食品科學系的研究人員金佰利·揚和羅賓·丹多曾研究過雜訊對5種基本味覺的影響。試驗結果發現，雜訊不會影響試驗人員對鹹、苦和酸這3種味覺的判斷。但如果機艙雜訊超過85分貝，人們對甜味的感知會減弱，對鮮味的感知會增強。因此，像番茄汁這樣味道濃烈的飲料，就會變得比平時更好喝。

In addition to the cabin environment, the facilities on board the aircraft can also affect the taste of the food. Food safety is always a top priority for airlines. When cooking on the ground, the choice of ingredients can be "imaginative", but the selection of materials for in-flight meals must be careful. According to the aviation food hygiene regulations, high-protein, high-carbohydrate, perishable and other ingredients have potential safety risks, so soy products and fried foods rarely appear on the airplane menu. In addition to freshness, the raw materials purchased for in-flight meals should also pay attention to appearance and detect pesticide residues in fruits and vegetables, such as cucumbers, so as to ensure that the amount of each meal is equal when cutting into pieces. Bonely, thorny, pungent food is hardly taken into account because it can easily choke passengers if there are bumps in the flight.

At the same time, passengers on the same flight may have vegetarians, people with allergies to certain foods, people who don't like spicy food, people who are lactose intolerant, pregnant women, people with poor immune systems...... Different dietary preferences and restrictions have made it necessary for airlines to cater to more travelers' tastes without sacrificing food safety. In addition, in-flight meals are generally refrigerated, dried, sealed and fresh-kept, and reheated before being served to passengers. This treatment, which is different from that of a ground meal, can also affect the taste of the food to some extent.

Although there are many factors affecting the taste of in-flight meals, major airlines have been working hard to improve the quality of meals in order to meet passengers' demand for food. On the basis of ensuring food safety, the chefs of many airlines continue to study the dishes and update the in-flight menus to provide passengers with more choices. In addition, most airlines have launched personalized services for passengers with special needs, such as children's meals, religious meals, vegetarian meals, medical meals and other special meals, which passengers can book in advance.

After learning about the "trivia" of in-flight meals, you may understand the challenges of making in-flight meals, and you may be able to better understand the good intentions of airlines. The next time you take a flight, you might as well try some "hidden" possibilities in the limited cabin conditions, choose foods with stronger umami, and maximize the pleasure brought by the food on board.