In the world of food, flavor is king. If it doesn’t taste good, we don’t want to eat it. Our survival depends on the fact that we keep eating food because it tastes good. Scientists say the tongue can distinguish only five primary tastes: sweet, salty, sour, bitter, and umami, also known as savory. Yet we seek out foods that offer a variety of flavor sensations, not just these five. How do we get from five basic tastes to endless flavor potential?
The Five Primary Tastes
The tongue is the main sensory organ for the taste system. Taste receptor cells on the tongue are clustered into papillae, little bumps commonly known as taste buds, but taste cells are also found on the roof of the mouth, in the throat, and even in the small intestine (where they may help regulate appetite). Taste cells have chemical receptors that detect specific molecules in food. For example, taste cells that recognize the taste of sweet have receptors that bind to parts of sugar molecules. When taste cells are stimulated by a sugar molecule, it signals a nearby nerve, which carries the message to the brain that you’re eating something sweet.
Taste receptor cells are specifically tuned to each of the primary five tastes. Why these five? It’s likely that sweet indicates ripe, edible fruits and sugary foods that are high in carbohydrates to provide energy, while saltiness indicates the presence of minerals like salt. Sourness detects acids, and bitterness detects poisons. Umami may be an indicator of proteins. Essentially, the five tastes are how humans have evolved to distinguish the edible from the harmful.
Smell Makes Up the Lion’s Share
When we think about what a food tastes like, we are thinking about the various complex, and often delicious, sensations that make up flavor. The brain analyzes flavor through a combination of the five tastes and smell. In fact, the olfactory sense contributes 80 to 90 percent of what the brain perceives as flavor.
Food stimulates our sense of smell when we inhale airborne molecules through the nostrils and when air wafts up the back of the throat and into the nose as we chew and move food around in the mouth. The olfactory nerves in the nose are sensitive to odorant molecules from food and send messages to the brain that enhance the taste messages coming from the taste receptors. The nose can distinguish anywhere from 10,000 to 100,000 different odors, allowing us to differentiate between not just apples and oranges but lemons and limes. Also, the hotter the food, the more odorant molecules evaporate into the air, the stronger the aroma, and the more the food stimulates the appetite.
Taste Is Tactile, Too
The sense of touch adds another dimension to flavor. Texture and feel influence our perception of flavor. A crunchy apple and a juicy orange make for more pleasant eating experiences than their mealy or dry counterparts do. A baguette is not the same without the crispy crunch of its fresh-baked crust. A smooth ice cream beats out a grainy, icy one. Even the fizz of a bubbly drink is a tactile sensation. Touch adds to the fun of food.
Spiciness is also a touch-related sensation that helps food pack a flavorful punch. The spicy kick from chilies is caused by compounds called capsaicinoids, which stimulate heat and pain receptors in the mouth, causing your mouth literally to burn in pain. The body’s nervous system releases pain-relieving endorphins in response, a pain-pleasure cycle that may explain why chili-laden foods are often so addicting. (Doesn’t everyone have a favorite hot sauce?) Whereas these foods set off heat receptors, menthol in mint simulates the feeling of cold temperatures. All these tactile sensations serve to enhance the flavors of food.
Taste Is Personal
One person’s yum is another’s yuck. Taste is highly subjective and personal, influenced by myriad factors from within and without. Moreover, our sense of taste and smell is always changing, and it’s possible to learn to appreciate new foods or old foods that we previously disliked.
