Maybe you felt the same – during the pandemic, many people have (re-)discovered their cooking and baking skill. More or less voluntarily. Some of us even for the very first time. People who usually go out to get their nutritional needs were suddenly forced to bring fresh vegetables, meat, or fish into their own oven.
Combining ingredients to create an uplifting and satisfying experience can be quite challenging and complex. Flavors are delicately designed with spices, oils, and essences, slowly building up during multiple and precisely timed stages of cooking until merging into a holistic sensation of taste between your jaws caused by chemical reactions.
What if we told you that you can enjoy the taste of a freshly baked pizza through your mobile device? Sounds too good to be true? Then, read on now…
Key Compounds Unlock the World of Taste.
Taste is one of the basic senses that help you to experience food and beverages. The taste of food is caused by its chemical compounds which react with receptor proteins in your taste buds.
Taste receptors are activated when food is chewed and mixed with saliva (commonly known as spit). Our tongue has a brush-like surface consisting of so-called papillae. These filament structures increase the surface area of the tongue and hence maximize the area of potential friction with food. Some of these papillae contain taste buds that are equipped with receptor proteins. These proteins ignore most of the food mush flowing around them until they detect their target group of food and flavor molecules. It is interesting to note that these proteins don’t have a narrow selectivity for specific molecules meaning they can be activated by a multitude of compounds.
Let us explain how by showing some small examples: compounds with Sodium ions trigger the salt perception, and a lot of different acids vividly trigger sourness. The whole process can be imagined as if the receptors are simple locks, and the compounds are keys. When the lock is opened, a chain reaction starts.
Once the protein is activated the whole taste bud cell comes to life and starts putting many more proteins inside the cell to work. These proteins cooperate by rapidly shifting electrically charged atoms around which produces a tiny electrical current inside the cell. This impulse is so tiny you cannot feel it.
However, it is detected by the underlying nerves in your tongue. These are specialists at detecting and passing on tiny electric signals. The signal is amplified until the message races out the back of your mouth, up through a tiny hole in your skull, and into your brain. This process only takes a few milliseconds. Your gustatory cortex (the taste center of your brain) finishes the job by telling you, which one of the general tastes you perceive: sweet, salty, bitter, sour, or savory.
Interestingly there are also interactions between different tastes and between taste substances. For example, the bitterness of coffee is suppressed by adding sugar. A synergetic effect for savory can be obtained by mixing Glutamine acid (E 620) and Inosinic acid (E 630). The savory taste is also known as “umami” coming from the Japanese language and might explain why many Asian seasoning mixtures rely on spices that contain Glutamine acid.
Everyone Has a Different Taste.
The threshold for the detection of taste compounds by humans also varies significantly. It is low for signals of toxic and rotten substances, i.e., bitterness and sourness (increasing in this order), and is highest for sweet substances, the energy source for humans.
Contrary to popular belief, the entire tongue can detect all five tastes. There isn’t a “zone” for each one. However, compared to the center of your tongue, the sides of your tongue are more sensitive to every type of taste. The exception is the back of your tongue. This area is extra sensitive to bitterness, which is thought to help us sense toxic foods before we swallow them.
The basic taste system is the same for all of us. However, we differ in the perception of each taste kind. This fact can be explained through the different quantities of taste buds. Each taste bud cell adds a little bit to the strength of a taste, so people with more taste buds are more sensitive to a particular taste.
The food industry today relies on sensory devices that can discriminate and analyze food and beverages, greatly contributing to quality management. These sensors use ion-selective electrodes to convert the concentration of flavor compounds into electrical signals. As an example, this enabled researchers to a uniform categorization of taste of different beer brands.
But can this process also be reversed to imitate a certain taste? This kind of technology can be helpful for a variety of industries and can take an interactive experience to a whole new level. The engineering discipline that deals with gustatory representation is called gustatory technology.
Electrodes are used to simulate the taste and texture of real food in the mouth. In 2012 a team of researchers at the National University of Singapore developed the digital lollipop, an electronic device capable of transmitting four major taste sensations (salty, sour, sweet, and bitter) to the tongue. The same team later in 2016 created a prototype with thermoelectric elements to simulate the sensation of sweetness through changes in temperature.
This approach doesn’t require any chemicals and purely relies on electronical and thermal emulation. The lock-key-mechanism is circumvented by short-circuiting the underlying nerves of the taste cells. This system could be implemented in mugs or drinking glasses to make low-sugar drinks taste sweeter and help people reduce their sugar intake.
A team from the University of Tokyo created a device that simulates the different textures of food also through electricity. The gadget uses electrodes that are placed on the masseter muscle (a jaw muscle used for chewing). It can simulate texture by changing the muscle frequency. For example, a higher frequency gives the food a harder texture.
Another Step to a Multi-Sensory Viewing Experience.
It is time to look at a chemical approach to this biochemical mechanism. Professor Homei Miyashita from Meiji University’s School of Science and Technology in Tokyo has developed a prototype lickable TV screen that can imitate food flavors.
The system is called Taste the TV (TTTV). His team of researchers used taste sensors to sample a variety of foods and came up with a palette of 10 different aerosol flavors. These base flavors can be combined in any ratio to approximate a great spectrum of tastes.
The device uses a carousel of different canisters that spray the flavor sample to be rolled on hygienic film over a flat TV screen for the viewer to try.
In the COVID-19 era, this kind of technology can enhance the way people connect and interact with the outside world, said Miyashita. “The goal is to make it possible for people to have the experience of something like eating at a restaurant on the other side of the world, even while staying at home,” he claims.
Miyashita works with a team of about 30 students that has produced a variety of flavor-related devices, including a fork that makes food taste richer. Potential applications include distance learning for sommeliers and cooks, and tasting games and quizzes, he said.
Miyashita has also been in talks with companies about using his spray technology for applications like a device that can apply a pizza or chocolate taste to a slice of toasted bread.
If we witness people constantly licking the surface of their mobile phones in the near future remains to be seen. But his technology adds another dimension to the rapidly expanding trend of digitization.
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