Taste: Surprising Stories and Science About Why Food Tastes Good (49 page)

Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in beer.

Humorist Dave Barry

A
ll foods are chemicals. Whether you’re eating a vine-ripened organic tomato or a Twinkie, all food can be broken down into its chemical constituents. A fresh tomato contains the aroma compound hexenal, among others chemical-y-sounding aromas. And a Twinkie contains sugar, among other natural components. These individual compounds give a food its characteristic flavor.

Our understanding of the individual molecules that make up flavor is deep. An entire industry exists for the manufacture and blending of these molecules. Flavor companies (also called flavor houses) sell ingredients, called, not surprisingly,
flavors
, that go into lots of different food. And you probably know nothing about them.

You do know something about the naturally occurring combination of taste, smell, and texture of a food—its flavor. For example, the natural flavor of a
peach is sweet, sour, fruity, floral, fresh, and juicy. But that’s only one definition of the word
flavor
. The second type of flavor is what you’ve seen written as “natural flavor” or “artificial flavor” in the list of ingredients in a beverage or frozen meal or cracker.

Some foods use “natural flavors” in place of real food ingredients. For example, there are peach-flavored drinks on the market that don’t contain any peaches, peach nectar, or peach juice. This type of drink gets its peachiness solely from natural peach flavor. In other products, natural flavors are used to replace the volatile aromas that are flashed off in the high temperatures of processing. For example, if you pasteurize pure peach nectar, you lose the fresh, juicy top notes because they’re low in molecular weight and evaporate off. You are left with sweet and sour tastes as well as some heavy cooked peach aromas that make it savor more like peach pie than fresh peaches. In order to make the nectar taste better, we might add back the fruity, floral, fresh, and juicy aromas that were lost in processing. And that’s exactly what natural flavors are: they’re aromas. They have no taste, but when you combine them with juice or sugar or acid (or salt, umami, or bitter), they become recognizable as a flavor. They should be called “aromas”—since they have no taste—but you’ll have to take that up with the U.S. Food and Drug Administration, which governs the labeling of food.

Adding a peach flavor to food is akin to adding peach fragrance to a body lotion. I asked Bell Flavors & Fragrances, a company that makes aromas for both foods and beauty products, to explain the difference between a flavor and a fragrance. The answer is, essentially, that flavors are experienced via nose-smelling and mouth-smelling whereas fragrances are experienced solely via nose-smelling. They’re both aromas but the difference is whether or not the FDA allows the compounds to be ingested. I assumed that the safety criteria for getting a molecule approved for ingestion would be much higher than for something you’re going to rub on your skin. It turns out the exact opposite is true. The molecules that go into beauty products are in contact with your skin for much longer than the molecules in what you eat. When you rub a scented lotion on your arm, for example, it may stay there for hours. Contrast this with consuming a fruity drink: the liquid is quickly shuttled into your bubbling and gurgling digestive tract where it’s immediately broken down by your body’s gastric acids and enzymes. Fragrances in beauty products are also used at much, much higher levels than the flavors that go into foods. A formula for a cologne, perfume, or body spray that contained peach fragrance, for example, could contain as much
as 10 percent fragrance. A peach flavor might liven up a peach nectar beverage at the low level of 1 percent (but usually less) of the formula. Ten times less.

If you were to walk into Mattson, you’d find tiny sample bottles of flavors throughout our food laboratory. We use peach flavor and strawberry flavor, but also wok spirit flavor and fried egg flavor. And my favorite: a seafood flavor that our VP of technology, Samson Hsia, calls
docky
, as in the place you dock your boat. Samson takes a bottle of it home to add a fishy funk to his homemade clam chowder. If you can imagine an aroma in a food or drink, we can purchase something in a bottle that delivers that smell.

If we’re creating something that we want to savor like a New Zealand sauvignon blanc wine, we might want to include the odor of cat urine, which is one of the characteristic aromas in this wine (not in a bad way). If we are working on a coffee drink, we might want to add that earthy peat moss smell that some coffees contain. Or if we’re creating a pizza-flavored snack for kids, we might add a tinge of pepperoni flavor to the seasoning—also a great way to make a vegetarian meal taste more like one with fatty pork.

While little bottles of liquid may sound scary, you probably have one in your pantry right now. Vanilla extract is a type of natural flavor. The aromatic compounds from vanilla beans are extracted into a liquid that you can buy to flavor cakes, cookies, pies, and ice cream. Natural flavors are similar.

Flavors are the secret ingredients that explain why you can’t create a carbonated drink that tastes exactly like a Coca-Cola. I have no insider knowledge, but the natural flavors that Coke uses are almost certainly made exclusively for it. You can’t buy Coke brand cola syrup to make your own cola. You can buy a Coca-Cola–
type
flavor, but no one can sell you the real Coca-Cola flavor because it’s likely that Coke has a few different suppliers that make multiple flavors that are shipped to Coke’s manufacturing plants, where they’re blended in secret proportions. There’s a lot of lore about the fact that no one single human being knows the entire Coke formula. This shouldn’t shock us. It’s common practice in the industry to use more than one flavor supplier so that no one single company knows the entire formula of
any
product.

Looking for powerful medicinal ingredients is like looking for a needle in a haystack. When a pharmaceutical company wants to test new drugs to see if they
work against cancer cells, the researchers put a bunch of cancer cells in a tray and expose the cells to treatments with various compounds. The more treatments you use, the more likely you are to find the rare compound that works on cancer cells.

This is exactly what flavor companies are doing to try to find chemical compounds that enhance sweetness, tame bitterness, or suppress tartness. Using this technique, called
high throughput frequency
, they look for flavor boosters the same way pharmaceutical companies look for new drugs. They put human taste receptor cells in a tray and expose them to various molecules, looking for some spark that indicates the taste receptor is perceiving something. This means that a particular molecule could be tickling the sweet receptor in the same way that sugar does, for example. The goal is to isolate, refine, and develop these compounds into ingredients that can safely be added to foods to make them taste better. These ingredients are called
enhancing flavors
or
masking flavors.
They’re used to mask foods with a bad taste (usually bitter) or enhance good tastes (usually sweet or salt).

To illustrate how masking flavors are used, let’s go back to Menerba, the extraordinarily bitter herbal hot flash remedy that we were trying to turn into a delicious beverage. When we were creating the drink mix, we did the best we could using culinary ingredients and techniques. But eventually we realized that the vanilla, salt, sugar, acids, and natural flavors weren’t balancing the bitterness of the Menerba enough to make it palatable. We needed more help. This is the point at which a food developer picks up the phone; calls a flavor company like Bell, Firmenich, Symrise, International Flavors & Fragrances (IFF), or Givaudan; and orders a masking flavor. Some of the most challenging foods in development today are those that are low in calories or sodium or have functional ingredients like vitamins added to them. When you remove sugar or salt, you often expose underlying bitter tastes or off-odors that aren’t pleasant. And adding vitamins, for example, can make a sports or energy drink taste like Flintstones vitamins. Unless this is what you’re going for, a masking flavor can help. In all of these situations.

The only way companies can sweeten food with stevia instead of sugar is by masking some of the bitter tastes and licorice-y aromas in stevia. The use of potassium chloride, which tastes salty but is lower in sodium than salt, can help replace some salt, but often a masking flavor is needed to minimize its metallic, bitter taste. When we added a bitter-masking flavor to Menerba I was shocked by how much better it tasted afterward. There is no way we could have achieved
this amount of bitter reduction without the high technology of a masking flavor. This compound, used at less than 1 percent of the formula, was working some kind of taste magic.

There are three ways that masking and enhancing flavors work. The first is by blocking or stimulating a taste receptor so that the receptor can’t read the taste properly. I asked Ken Krautt of IFF to explain how to block a bitter taste receptor. We have many different bitter receptors, so I was confused about how one ingredient could block all bitter tastes. It can’t, he told me. IFF makes different masking flavors to block different sources of bitterness. Then he quickly defaulted to using an analogy, with bitter receptors represented by cups.

“If you could imagine little cups lined up in a row. Each one of these cups represents a bitter receptor. You pour caffeine over these cups and it goes into one cup and registers as bitter. You pour naringin and it goes into another cup and that registers as bitter. And that goes on with different bitter agents. Now imagine you can manipulate these different components to go into different cups. So you’d be blocking the caffeine from going into the caffeine receptor cup, and maybe making it go into another receptor cup that would record it in a different way,” which could be something other than bitter.

The second way masking flavors work is by employing a concept like adaptation or cross-adaptation, which happens in the brain where taste, smell, and texture combine to form the concept of flavor. When Mary Poppins sang, “A spoonful of sugar helps the medicine go down,” she was advocating this method. When you add sugar to something bitter like medicine, you don’t do anything to block the bitter receptor. The medicine still goes into its bitter receptor cup. It’s just that when you eat sugar at the same time you eat the bitter compound, the perception of bitter is decreased in your brain. Masking flavors can do something similar with compounds that are targeted against a specific bitter taste. Volatile aromas can also enhance or suppress tastes and smells. It’s just a matter of finding the right ones for the job.

Changing the physical form of a bitter ingredient is the final way to accomplish masking. The dark red cinnamon-flavored coating that Advil applies to its ibuprofen tablets is an example of a method called
encapsulation.
We can also encapsulate much, much smaller particles, some as small as grains of salt. A superthin layer of neutral or flavored coating can be applied to crystals so that they will still flow. The objective is that by the time your saliva dissolves the coating, you will have already swallowed the food. It sneaks past your bitter taste receptors undetected.

Even though this type of flavor manipulation is happening all around you, it’s unlikely that you’ll ever notice it. That is, if it’s done well.

Imagine a barbecue at your best friends’ house. The sound of kids playing, the low thrum of Bruce Springsteen on the radio, the
spffft
of beer bottles being twisted open. Now imagine that someone places on the picnic table a platter stacked high with racks of baby back ribs, slathered with barbecue sauce or a dry spice rub—choose your style—fresh out of the mesquite cooker, crusty along the edges, falling-off-the-bone tender, smoky steam wafting off of them.

If you’re craving ribs right now, you’re human. And if I now present you with a huge platter piled high with individual ribs, already divided into singles for you, it’s likely you might eat
more
than you normally would had I not put the image of them in your head and sparked a craving for ribs.

Now imagine taking a rib from that platter and eating it, slowly, then reaching for another one and imagine eating it, and so on and so on—one at a time—until you’ve imagined eating ten of those delicious, sticky, messy ribs. If I now offer you that real platter of ribs it’s likely you’ll eat less than you normally would. Why? Because the simple act of imagining eating a food can reduce your subsequent actual consumption of that food. This is the concept of sensory-specific satiety, whereby each additional bite of a food tastes less and less good. With each bite you are less and less motivated to keep eating it, until . . . you . . . simply . . . stop . . . eating it. This happens even if the eating is happening only in your head. Yes: sensory-specific satiety can occur without the use of your senses.

The experiment that proved you could inhibit actual eating by first imagining eating was conducted by having real people eat real food: M&M’s and cubes of cheese. The fact that this works is even more interesting when you consider what’s going on in the brain.

At first it seems counterintuitive. We are built to love eating so that we’ll nourish ourselves, procreate, and ensure the continuation of the species. It’s a nice little system we’ve got going. Could it be true that the brain will allow us to be satiated with food that doesn’t even exist, much less pass our lips? The answer lies in a big white piece of machinery that allows us to see inside the brain, the
fMRI (functional magnetic resonance imaging) machine, which resembles an airline fuselage.

The MRI part is what allows us to look at the anatomy of the brain with a type of camera, by taking an image of it. The
f
preceding this acronym means that the person whose brain is being scanned is functioning, performing some sort of task while inside the camera. The brain is captured in slices, over time, as the task is being done. The resulting image is the closest thing we have to watching the brain in action. This is how we could see the phenomenon of imagined eating actually working. When you read the fMRI of someone imagining smelling ribs, for example, the image looks very similar to what you’d see if the person actually smelled the ribs. The same holds true for taste: imagining tasting ribs lights up the same regions of your brain that actually tasting them would light up. Of course, when the researchers did the experiments to prove this, they didn’t use ribs. They had to pipe tastes into the mouth with a tube and smells into the nose with an olfactometer. You can’t eat real food in a normal way in an fMRI because if your head moves when you are eating a rib, the resulting image will be blurry—just like what happens with a regular camera. There’s also the problem of getting the rib to your lips without moving and without getting barbecue sauce all over the million-dollar piece of research equipment. For these reasons, brain scans of people experiencing food to date have been somewhat limited to liquid tastes. Even so, they’re an ordeal to conduct.