The Science of Taste

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Confucius said, “Everyone eats and drinks, but few appreciate taste.” When you understand a bit about the science of taste, you may join the few who appreciate it. In fact, the science of taste is amazing. The human sensory systems allow us to distinguish about 100,000 different flavors.  Flavors emanate from our bodies’ ability to discern one taste from another.  And, according to the 2017 Food & Health Survey, taste reigns with 84 percent of Americans confirming it as “a top driver of [food] purchases.” 

What’s the difference between taste and flavor?

If you hold your nose, close your eyes and eat chocolate, you may not know what you are eating. Without your sense of smell, chocolate just tastes sweet or bitter. If you have ever tried to enjoy a meal with a head cold, you know how much your sense of smell adds to flavor.

Flavor is more than just odor and taste. It also includes texture and temperature. It even includes the sense of pain, which is what you get from capsaicin in chili peppers. Put it all together and you have the ability to discern 100,000 different flavors.

How did our sense of taste evolve?

Over millions of years, our sense of taste evolved to help us choose which foods to eat. Choosing the wrong food could mean wasted energy, poor nutrition or poisoning from eating something that can do harm to our bodies. According to Current Biology Perspective on Food and Human Taste, humans relied on fruit and other plant-based foods and eventually developed a strong sense for the natural bitter taste in plants and leaves.

As time progressed, we retained these early taste preferences and acquired newer ones. We like the taste of sweet because it signifies a source of sugar, which means energy. We like sour because it is a source of vitamin C. Our bodies don’t produce vitamin C, but it is essential for survival. We like salty because our early plant-source diet did not have enough salt. That’s why animals that don’t eat meat (herbivores) seek out salt licks.

What are the basic taste sensations?

Science reports in the world’s largest medical library, the U.S. National Library of Medicine, have identified five specific types of taste. Taste receptors in your mouth send these taste sensations to your brain: sweet, salty, bitter, sour and savory.

  • Sweet is the taste of natural sugars found in many fruits and honey.
  • Salty is the taste of sodium and chloride (salt crystals) and the mineral salts potassium and magnesium.
  • Bitter is the taste of 35 different proteins found in plants. Caution: Some of them, such as ricin in the castor bean plant, can be toxic.
  • Sour is the taste of acidic solutions like lemon juice and organic acids.
  • Savory comes from protein building blocks (amino acids) found naturally in protein-rich foods like meats and cheese.

Researchers are actively looking for more taste receptors. In the future, taste receptors for fat, alkaline (opposite of sour), metallic, starch, calcium and water may be added.

How does taste get from your tongue to your brain?

According to experts on smell and taste, the first step for solid foods is to break down food substances into molecules that can be identified. When you chew, enzymes in your saliva begin the process of digestion. The true receptors of taste are your taste buds. You have up to 4,000 of them, mostly located on the top and sides of your tongue. There are also taste buds in your mouth and throat.

Taste buds are found inside tiny bumps called papillae. Think of a papilla as a tiny castle tower with a moat around it. There are three types, and they are located on different parts of your tongue. All three types can detect all the taste sensations, but some specialize. For example:

  • Papillae at the back of your throat are most sensitive to bitter. They cause you to gag and spit out a bitter substance that could be toxic.
  • Fungiform papillae are located near the tip of your tongue. These are the most common type. There may be up to 400, with three to five taste buds in each.
  • Foliate papillae are located on the sides of your tongue. They look like folds along the sides of your tongue near the back. There are about 20 and they may each have several hundred buds.
  • Circumvallate papillae form a V at the back of your tongue. They are big enough for you to feel and see. There are about 12. Each one can have thousands of bitter-sensitive taste buds.

Your taste buds look like little flower buds located at the bottom of the moats. Each bud is made up of about 10 to 15 cells bunched closely together, like the segments of an orange. At the top of each cell are tiny finger-like projections called taste pores. When taste molecules fall into the mote, they attach to taste pores to be analyzed.

At the bottom of each taste cell are nerve fibers. After the cells sense taste molecules, they transmit signals to larger nerves called cranial nerves.  Cranial nerves that carry taste sensations to the brain are the facial, glossopharyngeal and vagus nerves.

Taste signals travel first to the base of the brain where some signals are processed. Signals are then sent along to higher brain areas. Some signals go to the ventral forebrain where they may trigger areas that control emotions and memories. That’s why some food flavors evoke memories. Other signals go the dorsal region, where triggers relay sensory signals to other parts of the brain. This may cause you to remember and crave certain flavors.

Evolution must have considered your sense of taste to be very important. It made your taste buds the only part of your nervous system that can completely regenerate when they get old or damaged.  The science of taste is amazing. Next time you sample your favorite flavor, take some time to really appreciate it.

This blog post was written by Dr. Chris Iliades.

About the Author

Dr. Chris Iliades has a medical degree and over 20 years of experience in clinical medicine and clinical research. Chris has been a full time medical writer and journalist since 2004. His byline appears in over 1,000 articles online including EverydayHealth, The Clinical Advisor, The Huffington Post, and Healthgrades. He has also written for print media including Cruising World Magazine, MD News, The Pulse, and The Johns Hopkins Children’s Center Magazine. Chris lives with his wife in Boothbay Harbor, Maine.