Auguste Escoffier was not just a chef; in Paris in the late 1800s he was the chef. He had opened the most glamorous, most expensive, most revolutionary restaurant in the city. He had written a cookbook, The Guide Culinaire. And, he also created meals that tasted like no combination of salty, sour, sweet, and bitter; they tasted new. He offered a spectacular new sauce that seemed to deepen and enrich the flavor of everything it touched.

But because it was neither sweet, bitter, sour, salty nor any combination of those four, as far as scientists were concerned, it wasn’t real. People may smack their lips, drool, savor, and pay enormous amounts of money to M. Escoffier, but what they tasted wasn’t really there. It was all in their heads.

Meanwhile, halfway across the world, a chemist named Kikunae Ikeda was at the very same time enjoying a bowl of dashi, a classic Japanese soup made from seaweed. He too sensed that he tasted something beyond categor[ization]. And it was, thought Ikeda, simply delicious.

But what was it? Being a chemist, Ikeda could find out. He knew what he tasted was, as he wrote, “common to asparagus, tomatoes, cheese and meat but… not one of the four well-known tastes.” Ikeda went into his lab and found the secret ingredient in 1908. He wrote in a journal for the Chemical Society of Tokyo that it was glutamic acid, but he decided to rename it. He called it umami (pronounced “oo-MA-mee”), which means “delicious” or “yummy” in Japanese. Ikeda then crystallized monosodium glutamate (MSG), the chemical ingredient responsible for umami, as a seasoning that would become popular worldwide, and began commercial distribution of MSG products. [1]

Almost 100 years after Escoffier wrote his cookbook and Ikeda wrote his article, a new generation of scientists took a closer look at the human tongue and discovered, just as those two had insisted, there is a fifth taste. When something is really, really yummy in a non-sweet, sour, bitter, or salty way, that’s L-glutamate you taste. This new taste was named “umami,” in Ikeda’s honor. [1]

Umami is a Japanese word that means “good flavor” or “good taste.” The closest English equivalent, taste-wise, is probably brothy or meaty. Umami describes the flavor common to savory products such as meat, cheese, and mushrooms. Bouillon cubes are the closest Western product that could be identified as umami. Unlike the other four tastes, umami is much vaguer and harder to pinpoint. All candies exhibit some sweetness, yet not all cheeses or vegetables will be umami. Although North Americans cannot easily identify this flavor, it’s quite easily recognized in many East Asian countries because the idea of umami is a part of the culture. Thai fish sauce, for instance, is pure umami.

Salts of umami, the most common of which is monosodium glutamate (MSG), are used as natural flavor enhancers which bring depth and balance to food without drowning out more subtle tastes. Valued at USD 4.5 billion, the global MSG market stood around 3,000 kilo tons in 2014. It appears in almost everything from fast food sausages to supermarket items like rapid-cooking soups, chips, bouillon cubes, ketchup, steak sauce, cheese, etc., providing flavor enhancement. What MSG has going for it is that it is a readily available, inexpensive, intensely umami ingredient with no off-flavors — just as sugar is a classic expression of sweet and salt is perfectly salty.

In many parts of Asia, it is as common to add a dash of MSG to dishes as it is for cooks here to toss in a little salt or sugar. But in the U.S., MSG has developed a bad reputation as a suspicious additive that many consumers believe causes allergies or headaches. [2] Concerns have been raised on anecdotal grounds. Hypotheses have been put forward that MSG may be associated with migraine headaches, food allergies, obesity, asthma, and hyperactivity in children, etc. Yet, subsequent research failed to present any causal association that MSG is responsible for these symptoms, even in studies with people convinced that they are sensitive to it. U.S. Food and Drug Administration “considers the addition of MSG to foods to be generally recognized as safe.” [4]

Umami in food

In the wake of breakthroughs in food science, umami is going mainstream. Chefs are offering dishes that pile on ingredients naturally rich in umami to reduce the fat and salt content of foods without sacrificing flavor. Just as a few shakes of salt can improve a dish, a correctly applied dash of cheese or ketchup can pump up the umami without overwhelming the dish. [2] Packaged-food companies are trying to ramp up the umami taste in foods like low-sodium soup to make them taste better. Companies that develop flavorings for the food industry are seeking ways of delivering the taste to foods while also cutting back on fat, salt, sugar, and artificial ingredients. These can range from natural ingredients to artificial flavors that are to MSG what saccharine and aspartame are to sugar. [2]

Umami blends well with other tastes to expand and ignite their flavors, and to awaken the taste buds. It is a subtle taste that occurs naturally in many vegetables and dairy products as well as in meat, fish, seafood, and their fermented or cured derivatives. However, it’s not as easily recognizable in the Western diet as sweet, salty, bitter, and sour. In Asian cuisines, umami is mainly found in beans and grain, fermented seafood-based products, shiitake mushrooms, soy sauce, fish sauce, Kombu, and dried seafood. These are all inherently rich in umami, without additives or chemicals. The most common example in Western cuisine is tomatoes. [3]

Tomatoes are an indispensable ingredient that form the basis of a wide variety of dishes. The glutamate levels in tomatoes increase significantly in condiment forms such as juice, ketchup, paste, or sauce. Today, tomatoes are one of the most widely produced vegetables and their umami taste, especially present in ripe, juicy beefsteak tomatoes, is appreciated all over the world. [3]

Foods high in protein are the best for sensing umami. Glutamate is released when protein is broken down through drying, aging, curing, smoking, slow-barbequing, or slow cooking; for instance, mushrooms better contribute to umami when sautéed, and meat that has been marinated is tastier. Many kinds of meat become tenderer when matured: the enzymes contained within the meat break down its proteins to increase the levels of umami-imparting amino acids. Processed beef products have higher levels of glutamate than meats do in their natural state. [3]

Already rich in glutamates, milk further releases glutamic acid when it is cultured and aged to produce cheese. That’s why aged cheeses, such as cheddar and parmesan, are grated over or stirred into other dishes as seasonings or used as toppings to add a savory flavor. Parmesan cheese, also high in protein, is one of the world’s most popular hard cheeses. More than two years are required for the maturation of parmesan. The glutamate content is so high that even a rind tossed into a soup pot deepens flavor. A large chunk of parmesan cheese will have small but visible white glutamate crystals, which were formed during maturation. [3]

The sweetness and umami of green tea is provided by amino acids. Teas – such as green, black, and oolong – all originate from the leaf of the same tea plant, but variations in the production and processing result in differing beverages. Most of the tea consumed in China and Japan is unroasted green tea, where the essential elements of the tea plant are left largely intact. [3]

Another food combining umami substances is the cheeseburger. Its combination of beef, cheese, and ketchup creates a delicious synergistic effect. The effect further increases when it is accompanied by fried potato, as potato slices lose water content when they are fried up, which concentrates the glutamic acid in each bite.3 Piles of umami toppings on pizza – tomatoes, pepperoni, mozzarella, and mushrooms – could explain why people love its savory taste and the full, tongue-coating sensation it provides.

Another role glutamates play

Glutamates are important neurotransmitters in the human brain and play a key element in learning and memory. A sweet taste signals a source of energy, through sugars and carbohydrates. A salty taste signals the presence minerals that are essential to keeping the mineral balance of the body’s fluids. Sour tastes signal that something has gone bad in the food, and a bitter taste, meanwhile, signals that something is harmful to the body, such as a toxin.

On the other hand, umami is the taste of amino acids or nucleotides, and plays the role of signaling the presence of proteins, which are essential to human beings. Just as sweets serve as an incentive for carbohydrates, glutamate helps us enjoy proteins.

Our body recognizes the various tastes via taste receptors on the surface of the tongue. Negating the opinion that each taste has its particular zone, research has revealed that all tastes can be detected anywhere around the tongue, as each taste bud has 50 to 100 receptors for each taste. Furthermore, separate taste receptors on the tongue with no purpose other than detecting umami have been discovered.

What is more, recent research has discovered that there are glutamate receptors not only on the tongue but also in the stomach. It has been ascertained that the pneumogastric vagus nerve only reacts to glutamate. This suggests that when a piece of food enters the stomach, and glutamate receptors detect the presence of glutamate, this information is relayed to the brain by the vagus nerve and an order is sent from the brain to the stomach to prepare for digestion.

As we see here, the whole system – of taste, sense, and digestion – is tied together. One can only marvel at the incredible design of such a complex system – maybe while enjoying a delicious, umami cheeseburger!

Notes

[1] Krulwich, Robert. “Sweet, Sour, Salty, Bitter… and Umami.” NPR. http://www.npr.org/templates/story/story.php?storyId=15819485.

[2] McLaughlin, Katy. “A New Taste Sensation.” The Wall Street Journal. http://online.wsj.com/article/SB119706514515417586.html.

[3] Umami Information Center. http://www.umamiinfo.com/.

[4] https://www.fda.gov/food/ingredientspackaginglabeling/foodadditivesingredients/ucm328728.htm

Figure 1. Examples of umami food

Like all omnivorous foods, peppers – both hot and sweet – have been created in unique, wise ways to make them appealing to eat and to help reproduce.

Plants and their fruits are sustenance for herbivores, including humans. They are often brightly colored – be it red, orange, yellow, purple, or green, inviting us to a delicious food. But not all plants are meant to be eaten. Indeed, some plants are designed to be unappetizing, either through look or smell; some even have thorns, or sticky, hairy surfaces to deter us from eating them. Another remarkable way that plants are protected against herbivores is the presence of unique chemicals that induce vomiting and pain, or may be toxic.

Many edible plants need to be eaten – it’s how they spread their seeds. Thus, they produce juicy, tasty skin and sweet-smelling aromas. Why, then, are hot peppers different? Though they are nicely colored and juicy, and sweet smelling, they are also hot, and not terribly pleasant for animals to eat.

A recent study at New Mexico State University’s Chile Pepper Institute determined the hottest chili to be the Trinidad Moruga Scorpion Chili. It was chosen from among 125 varieties. Researchers dried and ground it to powder, to isolate its active compound. This way, they were able to determine that the Trinidad Moruga Scorpion reaches about 1.2 million units on the Scoville heat scale. It is so potent that it could induce sweating and tears, and of course puts the mouth on fire.

Figure 1. Molecular mechanism of TRPV receptor activated by capsaicin. TRPVs are located on the surface of nerve cells where they normally respond to changes in temperature by releasing calcium ions. Those ions signal to intracellular machinery to fire nerve action to inform the brain about increased levels of heat. Capsaicin in hot peppers mimics this system, and thus fools brain to think mouth is hot.

What make hot peppers hot?

Animals are equipped with receptors, like TRPV1 in the mouth’s nerve endings, which sense heat. Hot peppers produce a chemical called capsaicin. Capsaicin binds to and activates TRPV1 receptors; thus we feel a heat similar to a burning sensation. In reality, capsaicin does not actually increase the temperature in the mouth, but instead mimics the same process (Figure 1). Since capsaicin mainly dissolves in oil instead of water, drinking water does not help much to get rid of the burning sensation. Cold water provides only temporary aid. However, the drinking of ayran (a Turkish yogurt drink) relieves hotness by removing capsaicin due to the presence of oil in ayran. Interestingly, although mammals have receptors for capsaicin, scientists have recently discovered that birds don’t.

Capsaicin deters mammalian consumption

It is an interesting phenomenon that peppers are hot but need to be eaten to propagate their seeds in different environments, which is done through the droppings of animals. If this is the case, why are hot peppers made unpleasant with capsaicin? To figure out the wisdom behind this contradiction, Joshua Tewksbury performed a study with a group of mice and birds, and found that birds do not distinguish between sweet and hot peppers in their diet. In this study, both mice and birds ate the same amount when fed with food mixed with sweet peppers. However, mice refused to eat foods mixed with hot peppers, while birds happily ate such food. Moreover, analysis of the droppings of birds and mice showed that the seeds passed through the bird’s digestion systems were intact and fully fertile and could germinate, while seeds eaten by mice were either crushed or semi digested so that they were not fertile. Thus, the role of capsaicin in hot peppers is to deter mammals that destroy their seeds while not disturbing birds. This is a great example of ingenious interdependence.

Capsaicin as antifungal agent of peppers

Figure 2. Capsaicin is not only protective against mammals but also fungus contaminations. A) Insects make peppers prone to fungus contamination by causing harm. B) Healthy pepper C) A pepper with fungal contamination. Modified Image from Tewksbury lab.

The infinite wisdom of capsaicin protects peppers against fungus as well. Another study by Tewksbury showed that hot peppers are relatively protected against fungal infections. Tewksbury demonstrated that increased doses of capsaicin inhibit the growth of fungus. This finding is in parallel with lower fungus growth in hot peppers compared to sweet peppers.

But what about insects? How could peppers be protected from insects?

Adaptations against insects

Interestingly, the skins of hot and sweet peppers have different levels of thickness. It has been suggested that this gives an advantage to sweet peppers. Furthermore, this protective layer is made of lignin, which is made of the same material as capsaicin and helps to protect from other threats. This allows peppers to adapt to many different environments. For instance, in the presence of fungal contamination, a pepper might be able to produce more capsaicin and decrease lignin production, or vice versa.

Why do we like to eat hot peppers then?

Humans differ from mammals in their love of hot peppers. There are different explanations why we like to eat hot peppers, despite them being painful. Some experts assert that hot peppers are good for our health by lowering blood pressure, having antimicrobial effects, and increasing salivation thus making a boring diet fun. On the other hand, some experts approach it from the perspective of human emotions and argue that we are actually after the pain produced by hot peppers. In addition, there are some studies suggesting that capsaicin could also suppress other pains.

Hot pepper or capsaicin as pain suppressor

Capsaicin in hot peppers could be used as a pain suppressor, as some studies suggested. A study using mice lacking TRPV1 heat receptors showed that the increased long term activation of TRPV1 by capsaicin could relieve pain following the accumulation of high doses of Ca2+ in the cells. This is accomplished by the suppression of both cellular activities and the transmission of pain through nerves.

Hot peppers are hot and we love them. It seems like we will continue consuming them. As every other art of creation, hot or sweet peppers are likely to have many more levels of wisdom awaiting us to discover.

References

• Tewksbury Lab. Retrieved from: http://faculty.washington.edu/tewksjj/res_pai.html on 18.2.2012.
• Yalgın. Ç. 2012. Acı biberler niye acı? (Why Are Peppers Hot?) Açık Bilim. Retrieved from: http://www.acikbilim.com on 18.2.2012.
• Zivkovic, B. 2006. Hot peppers – Why are they hot? A Blog Around The Clock.

The merchant asked: ‘What gift may I purchase for you, my pretty pet, and carry back for your pleasure and delight, all the way from India?’

The parrot spoke straightaway, as though he knew he would be asked and so had prepared an answer: ‘I will not ask that you bring me back any gift, but I would ask a favour of you, a task to perform for me in India.’

‘Ask, my pretty pet,’ said the merchant, very curious, ‘and if it is in my power to do what you ask, I will do it, God willing.’

‘Well, then,’ said the bird, ‘when you reach India and you see there many parrots like myself, address to them this speech. Say:

“So-and-So Parrot sends you his greetings. He longs to be with you, but he cannot be. He is, by the decree of Heaven, a prisoner of the good merchant who brings you this message, a slave in a cage, locked up.,,

Then convey to those parrots from me. “So-and-So Parrot begs you to remember him. Remember him, imprisoned in his cage, when you fly about freely in gardens of fragrant roses. Remember him, alone and without the company of his fellows, while you go about with one another, cheerful and jolly.”

Add also this plea to your speech, since the one who will understand it may be listening. Say: “What! Have you forgotten your friend so soon, that you can fly about happily in the company of others? It may be that I was at fault in my service of you, and you are punishing me by forgetting me in this way. Is that as it should be? Is it right to answer a wrong with a wrong? Would it not be better to answer a wrong with a right?

“And yet, because it is you, still you, who have turned away from me, your turning away is dear to me. It arouses my love the more. Even your anger, your revenge on me, is dearer to me than my own life. Your anger is fire, and it burns me with love. If that is the affect of your fire, how must your light be? If I ever escape this cage, I swear I shall make straight for your rose-garden. There, I shall sing songs of desire like the nightingale. The nightingale’s songs gather the thorns as well as the roses, the bitter as well as the sweet, in the same joyful embrace. In the songs of the nightingale, love surpasses the pleasures and pains of love, and is entirely and purely itself.”

The merchant listened to every word and promised to deliver his pet’s complaint as best he could.

Towards the end of his journeying in India, he came across a rose-garden in which were a company of parrots like his own pet bird. To them, according to his promise, he faithfully recounted the parrot’s words. One of the parrots who had been listening began to tremble and shake, then fell from its perch in the rose-tree, and lay on the ground, dead. The merchant was deeply upset. He said: ‘I have been the cause of that poor creature’s death!’ and he regretted that he had kept his promise.

On returning home, the good merchant gave to all the servants in his household the gifts that they had asked for. To the parrot, he said nothing. But the parrot demanded of him: ‘What of me? Did you not do what I asked? If you did, tell me what you saw and heard.’

‘I did do it,’ said the merchant, ‘and how deeply I regret that I did. I wish I had kept silent and not conveyed your words.’

‘Why do you repent of keeping a promise and fulfilling a trust?’ asked the parrot. ‘What has caused you to be so remorseful and upset?’

‘I conveyed your complaints to the parrots where I found them, and one was so touched by your pain that she trembled and dropped down dead.’

As soon as he heard this, the merchant’s parrot also began to tremble, then he seemed to lose balance, and fell onto the floor of his cage, cold and senseless.

The merchant was now so struck with grief and despair, he began to tear his hair and clothes. ‘My dear, sweet companion!’ he cried, ‘My singer of sweet songs! Keeper of my secrets! Ah, what shall I do without you? How shall I live without you?’ Then, in his great sadness, not knowing what else to do, the merchant took the corpse (as he thought) of his beloved pet out of the cage and laid it gently on the palm of his hand.

Suddenly, the parrot awoke and flew, through the open window, to the safety of the high branch of a tree in the garden. The merchant was relieved to see his pet well. He looked up into the tree at the bird and said:

‘Dear friend, explain to me the meaning of what that Indian parrot did, which enabled you to devise this trick to escape from your cage.’

‘She gave me excellent advice’, answered the parrot from the tree. ‘By her dying, she conveyed this advice to me: ‘Your own fine voice is the cause of your being in a cage. You are held in that way so that you may entertain people with your singing and your speech. Their praise and the flattering love of your master are the walls of your cage. Renounce your cage-renounce your voice and your master’s affection. Become dead as I am dead, and find freedom.’

‘Go in peace under the protection of God!’ said the merchant. ‘You have shown me the way to a far country to which we must all go, sooner or later. That is the great journey and I must prepare for it.