Chemistry of Flavor

 

Chemistry of Flavor

Flavor is caused by receptors in the mouth and nose detecting chemicals found within food. These receptors respond by producing signals that are interpreted by the brain as sensations of taste and aroma. Certain taste and aroma combinations are characteristic of particular foods.

For example, a green apple tastes the way it does because the unique combination of chemicals found naturally within it are perceived by our mouths, noses and brains as the distinct blend of sweet and sour tastes and volatile aromas characteristic to the fruit. Identifying this chemical profile allows food producers to retain flavor in preserved green apples and, through synthesis of these flavor compounds, makes possible the production of candy, soda and other products using artificial green apple flavor.

The chemicals that produce flavors are notoriously difficult to study because a single natural flavor may contain hundreds or even thousands of component substances, and some of these substances are present in minute quantities. For example, one of the nine key aroma compounds found in pineapple is so potent that human subjects can detect it at only 6 parts per trillion—the equivalent of a few grains of sugar in an Olympic-size swimming pool. Understanding the components of flavor has become more important than ever with the modernization of food systems and the increased reliance on processed foods.

What is flavor?

 

What is flavor?

Taste plus smell equals flavor. We can detect five tastes (sweet, salty, bitter, sour and umami), and we can smell as many as 40 billion molecules. When they mix together in food, that can translate to more than a trillion possible flavors.

What does flavor have to do with chemistry?

Everything! We experience flavor in our brains, but it depends on taste and smell, which are chemical senses. That means we’re using our tongue and nose to sense molecules. Everything you taste—all the flavors you’ve ever experienced—are molecules.   

Can you tell how a molecule is going to taste from its structure?

We don’t have a perfect roadmap for flavor perception based on chemistry the way we do for color and sound, which are based on physics. But we do have a pretty good idea about a lot of things. For example, if you have a carbohydrate that’s not very big, there’s a good chance it’s going to be sweet. If a molecule is an acid, it’s almost definitely sour. 

Why do some plants produce seeds, roots, and bark that taste so good to humans?

We still don’t have a great idea about how to predict how a molecule smells just from its structure. We know from genetics that humans have around 400 types of smell receptors, but we’re still figuring out how they all work. We can make an educated guess about what a molecule is going to smell like, but it’s still a mystery how the brain translates signals from the smell receptors into the psychological experience of a smell or a flavor. 

Some people are using AI to analyze very large data sets to understand it. Others are taking a biology route by growing receptors in Petri dishes and seeing what kind of molecules they bind to. Some people are doing X-ray crystallography and structural studies to better understand the molecules themselves. Pretty much every area of chemistry has something useful to tell us about how flavor and smell work.