Any true connoisseur of food understands that all of our senses (taste, smell, sight, touch, and hearing) play a role in how we experience and enjoy food. I agree with the website WeGotTaste.com, which states:
"The human body is amazing! Our body gives us a variety of different methods to interact with the world we live in. We receive information from the world via our senses. Each sense is distinct and different. ... Two people can be in the same situation but based on what they sense, they will each experience something different. Everyone relies upon their senses differently and some of the senses may be more accurate than others. ... The sense of taste teaches us flavors of food. We learn what things taste like so we can recognize what is good and bad for our body to ingest. With the variety of foods there are to eat and enjoy, it is not surprising that eating is one of our favorite things to do. Our senses all interact with each other and pass on information to our brain. Once received, our mind interprets everything and logs it away into memory. This process is what creates the individual experiences we enjoy."
Most people are aware of the close connection between the sense of smell and the sense of taste; but, they may not be aware of other sensory relationships associated with how we enjoy food. Let's begin with discussion with the basic sense of taste.
Taste is a complex subject, but let me provide you with the Cliff's Notes version of how our sense of taste works:
"The stimuli for taste are chemical substances dissolved in water or other fluids. Taste can be described as four basic sensations, sweet, sour, salty, and bitter, which can be combined in various ways to make all other taste sensations. Taste receptors (called taste buds) for these sensations are located primarily on various areas of the tongue: front, sweet; sides, sour; sides and front, salty; and back, bitter (see the attached figure). There are about 10,000 taste buds, which are situated primarily in or around the bumps (papillae) on the tongue. Each papilla contains several taste buds, from which information is sent by afferent nerves to the thalamus and, ultimately, to areas in the cortex." ["The Chemical Senses: Taste and Smell," CliffsNotes.com, 26 April 2013]
Some people now add a fifth sensation, umami, a Japanese word that can be translated "pleasant savory taste." The medical description of taste may not make food and flavors sound very exciting, but you have to admit that it is amazing that four or five basic sensations can produce the phenomenal number of tastes we experience when eating. As noted above, there is special relationship between the senses of taste and smell. So it's natural that we next discuss the sense of smell.
Smell and Taste
Before they started flavoring children's medicines, there were some pretty nasty tasting concoctions prescribed by doctors. Inevitably, mothers would tell their children to hold their noses while swallowing the stuff. For many children, the act of holding their nose while consuming something unpleasant was their first exposure to the relationship between taste and smell. The Cliff's Notes page says this about smell.
"The stimuli for smell are volatile chemical substances suspended in the air. These molecules stimulate the olfactory receptors, which are in the upper portions of the nasal passages. Neurons from these receptors bundle together to form the olfactory nerve, which travels to the olfactory bulb at the base of the brain. The theory of smell is not well understood (for example, how an odor of apple pie can evoke pleasant childhood memories)."
Interestingly, new research claims that the nasal passage isn't the only area in the body that contains odorant receptors. ["Odorant Receptors Found In Non-Olfactory Cells," Medical News Today, 8 April 2013] The article reports:
"In a discovery suggesting that odors may have a far more important role in life than previously believed, scientists have found that heart, blood, lung and other cells in the body have the same receptors for sensing odors that exist in the nose. It opens the door to questions about whether the heart, for instance, 'smells' that fresh-brewed cup of coffee or cinnamon bun, according to the research leader, ... Peter Schieberle, Ph.D., an international authority on food chemistry and technology."
I'll return to Dr. Schieberle's work later in this post. The next sense I'd like to discuss is sight.
Sight and Taste
Most of us are aware that food presentation is important. Debra Zellner, a professor of psychology at Montclair State University, believes that how a food looks can affect its taste. ["Professor Talk: What Attracts Us To Certain Foods?" by Mike D'Onofrio, Montclair Patch, 17 February 2013] Dr. Zellner states:
"Colored beverages are perceived to smell stronger. But when people drink it, it tastes weaker. It is what is called a contrast effect, where people are expecting something that is stronger than what they get. ... How a food is prepared on a plate can [also] have an effect on a food’s taste. We did an experiment where we used the same chicken salad but prepared one neatly on a plate, and the other unbalanced and messy. People tasted both plates said the chicken salad on the neatly prepared plate tasted better, so presentation also matters."
Terry E. Acree, Ph.D, agrees with Professor Zellner, he claims, "The eyes sometimes have it, beating out the tongue, nose and brain in the emotional and biochemical balloting that determines the taste and allure of food." ["Biochemical Balloting: 'Seeing' The Flavor Of Food," Science 2.0, 20 April 2013] "Years ago," he states, "taste was a table with two legs—taste and odor. Now we are beginning to understand that flavor depends on parts of the brain that involve taste, odor, touch and vision. The sum total of these signals, plus our emotions and past experiences, result in perception of flavors, and determine whether we like or dislike specific foods." The one sense that Acree didn't mention was hearing.
Hearing and Taste
The WeGotTaste.com page states, "Sounds affect the interpretation our mind gets, but not as much as smells and sight." We're all familiar with certain sounds associated with food, like sizzling bacon, popping corn, or percolating coffee. Nevertheless, the folks at WeGotTaste.com conclude, "Sounds do not really affect the way food tastes. Taste and sound are brought together in the mind, but do not have a whole lot of meaning together." A mother and blogger who goes by the nom de plume "mealtimehostage" isn't so sure. She writes:
"Back in January, my friend came down with a doozy of a cold, the kind that finds its way into every sinus nook and cranny. Excessive mucous accumulating in the back of her nose prevented retronasal airflow into her nasal cavity. I found it intriguing how congestion had altered her senses, and changed her preferences and perceptions of food. ... The congestion also affected my friend’s hearing, creating intermittent periods of muffled sounds, followed by periodic crackling and popping. Not uncommon with a cold, but I’m sure you're asking. What on earth do ears have to do with our sense of taste? My knowledge of ear anatomy is limited at best, but I do know the ear canals and sinus cavities are all somehow connected. Interestingly, the ear is where we find one particular nerve that has a profound effect on taste nerves and the pain fibers on the tongue."
Although mealtimehostage makes it perfectly clear that she has no scientific or medical background, she found studies that linked childhood middle ear infections and "selective eaters." The nerve she talks about is the chorda tympani. She found the following description of that nerve:
"The chorda tympani is responsible for the taste perception on the front of the tongue. If that nerve becomes damaged, tastes at the back of the tongue actually get enhanced to preserve overall 'taste constancy.' But other cues that go into our sensory experience of flavor, including texture, smells and chemical sensitivity, are also enhanced." ~ Derek Snyder, Yale University neuroscience graduate student
She discusses a couple of other studies she found of interest including one that reported "when a small sample of adult selective eaters were asked if they had middle ear issues, 27 out of 34 respondents reported they had suffered from some form of middle ear issue in early childhood." Mealtimehostage may just be on to something.
Touch and Taste
Whether you've consciously thought about the relationship between touch and taste, you have subconsciously made the connection. Mushy cereal, soggy potato chips, and other not-so-appetizing foods may still be nutritionally valuable; but, because of how they feel, they become unpalatable for most of us. There is probably an evolutionary explanation for why the feel of some foods repels us. A mushy apple, for example, may indicate that it has gone rotten and could be dangerous to eat. John S. Allen, a neuroanthropologist, wrote a book entitled "The Omnivorous Mind," in which he "explores our biological equipment for taste and the ways in which each culture builds a unique cuisine upon a shared cognitive blueprint." ["An Accounting For Taste,"by Leo Coleman, Wall Street Journal, 20 May 2012] In a review of the book, Coleman writes:
"[Allen] observes ... that crispness seems to be a desirable quality of foods, whether in the crunchy crickets treated as a delicacy by some cultures or in Kentucky Fried Chicken. Such universals suggest that a deeply ingrained culinary capacity is an essential part of every human's 'biocultural' equipment, comparable to the cognitive capacities for language and empathy that indisputably marked important frontiers in human evolution."
In other words, touch may have a more profound effect on our sense of taste than we may have imagined. Earlier, I wrote that I would return to the work being done by Dr. Schieberle. I wanted to end this post discussing his work because it involves how the senses affect taste. The Medical News Today article reports, "Schieberle's group and colleagues at the Technical University of Munich work in a field termed 'sensomics,' which focuses on understanding exactly how the mouth and the nose sense key aroma, taste and texture compounds in foods, especially comfort foods like chocolate and roasted coffee." The article continues:
"For example, baked beans and beans in foods like chili provide a 'full,' rich mouth-feel. Adding the component of beans responsible for this texture to another food could give it the same sensation in the mouth, he explained. Natural components also can interact with substances in foods to create new sensations. The researchers use sensomics to better understand why foods taste, feel and smell appetizing or unappetizing. They use laboratory instruments to pick apart the chemical components. They then put those components together in different combinations and give these versions to human taste-testers who evaluate the foods. In this way, they discovered that although coffee contains 1,000 potential odor components, only 25 actually interact with an odor receptor in the nose and are smelled. 'Receptors help us sense flavors and aromas in the mouth and nose,' said Schieberle. 'These receptors are called G-protein-coupled receptors, and they were the topic of the Nobel Prize in Chemistry in 2012. They translate these sensations into a perception in the brain telling us about the qualities of a food.' Odorant receptors and the organization of the olfactory system also were the topic of the 2004 Nobel Prize in Medicine. Of the total of around 1,000 receptors in the human body, about 800 of these are G-protein-coupled receptors, he said. Half of these G-protein-coupled receptors sense and translate aromas. But only 27 taste receptors exist. And although much research in the food industry has gone into identifying food components, little effort has focused on the tying those components to flavor perceptions until now, he said."
Undoubtedly, a lot more research is going to be conducted about relationships between our senses and how they can affect our perception of flavors.