How the Brain Creates Flavor
The worlds we see, hear, feel, smell and taste exist independently, but we know them only through the fabrication of our brains. The colors we see do not exist apart from our perception of them. The words and sentences we believe we are hearing are a jumble of sounds, whistles grunts and silences.
-Our sensory worlds—vision, hearing, and touch—are created by combinations of physical characteristics in our environments that stimulate our eyes and ears and skin surfaces. These combinations simplify and stabilize our sensory worlds.
-A common misconception is that foods contain the flavors. Foods do contain flavormolecules, but the flavors of these molecules are actually created by our brains. How does it make combinations of chemicals into smell and taste?
-First, the taste receptors on the tongue respond to a broad range of molecules, neatly categorizing them into five types: sweet, salty, sour, bitter and umami (from the Japanese—a savory or meaty taste). The distinctive balance of these five characteristics makes up the “taste profile” of a particular item of food. The molecules the brain perceives as bitter bind specifically to bitter receptors on the tongue, the molecules perceived as salty bind specifically to salt receptors, and so on, much as keys fit into specific locks.
-The five categories of taste and the sensations associated with them are innate sensitivities.
-In fact, when we taste wine, we are not simply perceiving taste, but a synthesis of odor and taste, which create flavor. While there are only five types of taste receptors on the tongue, there are, in our nasal passages, about a thousand receptors for different types of odors. When we smell, the brain converts the responses of our individual odor receptors into a two dimensional spatial pattern in our brain cells.
-The brain recognizes and remembers smells by comparing the two dimensional images created from the patterns of our nasal receptor responses when stimulated by new sensations of smell.
-There are two ways that we “sniff”….by inhaling directly through our nasal passages.
This is called orthonasal smell….But a second source of smells we recognize comes from the back of the mouth when we chew bread, meat and other foods, the chewing releases molecules on our tongue surface into the backs of our nasal passages, and the resulting smell contributes significantly to the flavor we experience….This is called retronasal.
-Unlike the simple tastes, which are hardwired from birth, our responses to retronasal smells are learned. This is what accounts for preferences.
-The fusion of the sense of taste with smell creates flavors….Flavor is largely a consequence of smell; but very few people are aware that flavor is an invention of the brain that arises from smell and taste, and not simply from taste.
-Take a piece of candy, put it on the tip of your tongue, and pinch your nose. If you successfully block any air from entering your nasal passages, you will not notice that the piece of candy is sweet. If you then release your nose, letting air into your nostrils, you will suddenly “experience the flavor of the candy.”
-The flavors of foods, especially those flavors arising from sugar, salt and fat, are essential to our desire to keep eating.
-Consciousness itself, like memory, is an integration of past and immediate sensory experience. We are conscious of neither the past as such nor the immediate presence, but of a synthesis of past and present that, like the colors we see and the flavors we taste, is a creation of the brain.