The Biology of Taste
As one of the five senses (the others being smell, vision, touch and hearing) taste plays the leading role in what this blog is all about…healthy food and the enjoyment thereof. It is taste that interprets the flavor of foods and beverages and either switches on the taste gauge to ‘Ahhh’ or ‘Yuck!’ The sense of taste works hand in hand with smell (the other chemical sense) to interpret the chemicals in foods and other substances…but as I discovered it isn’t that simple. Taste is a very complex process highly influenced not only by smell and aroma but also by the texture of foods and, although the sense of taste is partially inherited, it is also affected by environment or culture and our familiarity with certain ‘flavors’. This is why some people love hot and spicy foods while others can’t even tolerate the slightest bit of spice or heat. The question is why? What really makes the difference in our eating habits, in what we enjoy eating. Why are there some foods that we really enjoy eating while some others are totally unappealing? In fact, to take it to the extreme, why don’t all people eat the same type of food? After all cows eat mostly grass, rabbits are known connoisseurs of carrots and monkeys are forever tied at the hip to bananas. To answer this question, we as cooks need to understand how taste buds work and then we can create the perfect menu for a specific set of dinner guests that will have them raving about the meal for weeks!
The sense of taste is centered in the mouth, more specifically, taste buds…but what exactly are taste buds? Taste buds are little clusters of cells in our mouth that mainly cover the tongue but are also found in the cheek, roof of the mouth and even in our throats! Taste buds have little hairs on them, called ‘microvillus’, that help reach out and grab tastes as they pass over the taste ‘bud’, so called because they actually do look like little plant buds under a microscope. And, just as the eye can only see four major colors: red, orange, green and yellow, the taste bud actually only processes four major areas of taste: sweet, salty, sour and bitter. That’s it. There are just four tastes that we can actually, well…taste! And get this; each taste bud has receptors for all four flavors and it is the taste bud’s job to decipher each individual taste as the flavor rolls over it…talk about multi-tasking, these guys are working! Some folks will argue that there is a fifth taste, savory or umami, but I’m only addressing what is commonly accepted as the major taste groups.
Without getting to technical, the microvillus grab and absorb the flavor and then send a message to the brain telling us what category of taste that whatever we’ve just eaten falls into. The brain then interprets the ‘flavor’ of the taste. The most common tastes, and the easiest for the brain to decipher, are sweet and salty. Sour and bitter are much more complex and a whole other story. We might think of sweet and salty as being polar opposites but, just as in the Paula Abdul song or magnetic poles, opposites do attract. There is probably no other combination of tastes that complement each other like sweet and salty, which explains the empty bag of chocolate covered pretzels…just kidding!
Let’s Talk Numbers
I mentioned earlier that this topic came about because of a discussion I had lately. That discussion was specifically about how long it takes for taste buds to regenerate…and neither of us had a clue. Well, first, it is important to understand the magnitude of the number of cells that we’re talking about. There are approximately 10,000 taste buds in the human mouth, give or take a few thousand. I say give or take because the older we get the number of active taste buds diminishes. Yep, another curse for the aged, as if arthritis wasn’t enough! Actually, 10,000 isn’t that much when you consider that a cow has about 25,000 taste buds…and they eat field grass! Anyway, and further, if you’re a smoker, you have even fewer taste buds. The average adult smoker has half the active taste buds of the average adult non-smoker. Take into further consideration people with chronic sinusitis and the taste factor diminishes even further! But, never fear, there is hope! You see, taste buds are some of the fastest regenerating cells in the human body. The average taste bud has a life expectancy of 10 days. That’s right, I said TEN DAYS! So, if you quit smoking today, you can have your full tasting capacity back by the end of next week…another great reason to stop smoking! Oral hygiene also plays a role, so take care of your tongue and it will reward you with great flavor detection.
The Nose Knows
As mentioned, the second sense that is extremely involved in the physical process of taste is our sense of smell. Here’s how it works. When you bite into something the food releases chemicals (aromas) that immediately shoot up your nose and trigger additional sensors called olfactory receptors. These receptors are located in the upper part of the nose and are solely responsible for the sense of smell. Once the aroma of food hits these receptors they immediately send and urgent message to the brain telling it whether or not the aroma is ‘pleasant’ or not. This is exactly why when you have a cold and your nose is stuffed up you don’t taste food (or anything else) the same as when your nose is clear. When you have a cold and the upper part of the nose is blocked the food’s aroma never reaches far enough up your nose to trigger the olfactory sensors, hence, no flavor or dulled flavor. This is also why you should never try a new recipe out when you have a cold…you can't taste and the food will never come out right!
Take a Bite of This
So, therefore and thusly, the sense of taste is much more than mere taste alone. It is a complex combination of both oral and olfactory sensors, working together in perfect harmony. To test this out, try having someone feed you something (i.e something sweet) while holding your nose closed…and closing your eyes, no peeking! While your mouth will be able to tell you that what you’re eating is sweet, you will probably not be able to tell exactly what it is until you release the grip on your schnoz and get a whiff. I’m not saying this’ll be the next great party game but try it with a friend, it’ll be fun!
A Cultural Thing
In addition to all the biology and genetics of taste, scientists at Johns Hopkins and many other leading universities tell us that taste is also the result of cultural differences, which only makes sense. If you’ve ever traveled to another country, or even a different region within your country, you were definitely exposed to new flavors. These flavors may seem strange at first but, I promise you, if you eat something long enough, you can and will become accustomed to it. That’s why my four year old twin nephews in Peru can eat a chili that would make me cry like a school girl all the while laughing at me with glee. They are accustomed to eating very spicy foods as a part of their culture and diet, it’s not a bad thing, it’s just that simple.
You Eat First With Your Eyes
In addition to all the science of flavor I would add one more ‘sense’, the sense of aesthetics…the beauty of food. There is a huge difference in appeal between looking at a plate that is just thrown together willy-nilly and a plate that is organized, clean and elegant…and you can taste the difference with your eyes. The most often use of the word 'appetizing' is to describe the look of food.This is why I and every other chef will go out of our way to have photos of food that looks good…you first eat with your eyes!
So then, we have learned that flavor, or taste, is not only dependant on biological influences but also depends on our exposure to different kinds of food, seasonings and the resulting flavors that they produce…the culture of food. We have all heard the expression “it’s an acquired taste”. My brother once told me that scotch was an ‘acquired taste’ and I woke up with a headache…but you can only develop a taste for something if you try it, so jump on in…the flavor pool is open and oh, taste buds are wasted on cows!
Cook and eat healthy and well!