Showing posts with label Smell. Show all posts
Showing posts with label Smell. Show all posts

Wednesday, 9 October 2013

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Tongue Papillae Diagram

Have you taken a close look at your taste buds lately? Go ahead -- take a look! When you stick out your tongue, you see that it's covered in lots of little bumps. We like to think of these bumps as our taste buds, but actually, these bumps are known as papillae. Your actual taste buds are much smaller, and anywhere from 3-100 of them can fit inside a single papilla.1 Take another look at your tongue. Notice how some papillae look different than others? There are actually four different types! Right in the center of your tongue, there are lots of small, skinny papillae that almost look fur-like. These are called filiform, and they don't contain any taste buds. On the front and sides of your tongue there are little round dot-like papillae known as fungiform.2 They usually contain 3-5 taste buds each. The next two types can be hard to see, but take a look all the way at the back of your tongue, near your tonsils. You may be able to make out a few ridges on either side of your tongue. Those are called foliate. On the top of your tongue in that same area, you might see some large, round papillae. These are known as circumvallate, and they, along with the foliate type, each contain more than 100 taste buds each!1

Tongue Map Myth

Looking at the positions of your papillae on your tongue may bring to mind a memory from grade school when you learned about the tongue map. The tongue map shows that different areas of your tongue taste different things, like salty, sweet, sour, and bitter. But don't be fooled. The tongue map is a myth! Each taste bud, no matter where it is on your tongue, has the potential to pick up on any of the five known tastes (more on that in a minute).3

Now let's take a closer look at a taste bud! As you can see from the diagram below, a taste bud is made up of two types of cells -- gustatory cells, which do all the actual tasting, and supporting cells, that are simply there to support the structure and function of the gustatory cells. Above each taste bud is a taste pore, which is simply an opening that allows food molecules to come in contact with gustatory cells. Each gustatory cell has a hair-like projection, called (not surprisingly) a gustatory hair, which hangs out near the taste pore all day. Taste Bud Diagram

When a food molecule comes in contact with a hair, the gustatory cell sends an electrical impulse to the brain letting it know that a taste happened! The message is sent through the cranial nerve, which connects all of our taste buds to our brain.2
A single taste bud can contain 30-50 gustatory cells each!3 That means your brain is processing thousands of signals from your taste buds at one time. Your brain takes the information your taste buds are sending, and it compares it with memories of things you've tasted before. That's how your brain recognizes what you're eating! A taste is defined as something that sends a chemical signal to your brain through your taste buds. You might be surprised to hear that there are only five tastes: sweet, salty, sour, bitter, and savory.4 Everything else, your taste buds ignore! But we all know there's more to food than just those five tastes, and that's where odor and mouthfeel come in.

Flavor, in the technical sense, is defined as the combined sensations of taste (from taste buds) odor, and mouthfeel. Mouthfeel means the way food feels in your mouth. It encompasses texture, moisture level, fluidity, temperature, chewiness, greasiness, astringency, pain (like that from hot chili peppers), and any other tactile experience we get while chewing or swallowing. It may seem strange at first to consider the smell and texture as a food to be a part of its flavor, but your brain is already taking into account these things when it's processing whether you find a food pleasant or not. Take beef jerky for example. If you dug into a bag of beef jerky only to find out that it was dried out and tough, you'd call it "bad" beef jerky. Even if it has the exact same taste and odor molecules as a "good" bag, the terrible mouthfeel ruins it! And that's true for a lot of foods, like soggy cereal, warm soda or stale chips.

Smell Diagram

When it comes to odor, your body smells on autopilot. While you chew and swallow (and breathe), your body is funneling all the tiny floating odor molecules around you (including those inside your mouth) up and into your nasal cavity where your olfactory cells live. You can think of olfactory cells the taste buds of the nose. They operate on a lot of the same principles. They hang a wee hair into the air space, and when an odor molecule comes in contact, they send a signal to the brain, via the olfactory nerve, letting it know what it picked up. But unlike the gustatory cells in your taste buds, olfactory cells can identify thousands of different odors! To name a few: toasty, nutty, fruity, garlic, fatty, fishy, meaty, floral, grassy/green, rancid, and burnt. (Visit Flavornet.org for a complete list of known odors.) Pretty much every aspect of flavor that isn't sweet, salty, sour, bitter, or savory is actually an odor! And that's why odor is so important to the flavor of a food. It also explains why food tastes different when your nose is stuffed up.

Isn't it fascinating to realize all the work your body is doing while you're doing something as (seemingly) brainless as eating? It's kind of awesome. Food's a complex chemical, and so are you!


1. Society of Sensory Professionals. "Taste Anatomy." Accessed September 19, 2013. http://www.sensorysociety.org/ssp/wiki/Taste_Anatomy/.
2. Marion Bennion, The Science of Food (San Francisco: Harper & Row Publishers, 1980), 5-6.
3. Institute of Food Technologists, "Sensory Science 101: Part 1: Taste and Smell" (Power Point Presentation , 2007), slide 7.
4. Amy Brown, Understanding Food: Principles and Preparation, 2nd Edition (Belmont: Wadsworth/Thomson Learning, 2004), 3-4.

Follow Amanda Greene on Twitter: www.twitter.com/DecodingDelish

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Monday, 30 September 2013

Anna Lappe
Project Director, Food MythBusters and author of "Diet for a Hot Planet: The Climate Crisis at the End of Your Fork"

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A doorstop of a report arrived in inboxes this morning. Not so subtly called: "Wake up Before It Is Too Late," the United Nations Conference on Trade and Development new report is a rallying cry for action to move toward greater sustainability in food and farming -- to ensure food security in a changing climate.

When Monsanto and other chemical companies are pushing hard on the claim that we need their products to feed the world, when The New York Times is publishing multi-page articles on the benefits of genetic engineering, the report comes at a particularly important moment. Its authors include some of the world's leading experts on food, sustainability, and agroecology, including Miguel Altieri, UC Berkeley professor, and Olivier De Schutter, the United Nations Special Rapporteur on the Right to Food.

Three key findings: First, the dominant message most of us hear about hunger reduction continues to be "Grow more food!" There is not nearly enough emphasis, the report argues, on the economic and social context of hunger. "Hunger and malnutrition," the authors write, "are mainly related to lack of purchasing power and/or inability of rural poor to be self-sufficient."

In other words, to address the roots of hunger we must be occupied with how to empower farmers and promote what is known as food sovereignty. As my mother, Frances Moore Lappé, has been saying since her seminal 1977 book, Food First, "hunger is not caused by a scarcity of food, but by a scarcity of democracy."

Secondly, the report calls for nothing less than a "paradigm shift" in growing our food, away from input-intensive, monoculture agriculture, toward what they call "ecological intensification." This means not only rethinking on-farm practices, but also rethinking the farmer herself: seeing farmers as not just producers of agricultural goods, but as stewards of the land, providing us all a valuable service in protecting soil, water, biodiversity, even climate stability.

When I was writing my latest book, Diet for a Hot Planet, this was perhaps my biggest a-ha moment: Yes, farmers are at the frontlines of the climate crisis -- often the first and hardest hit by climate disasters -- but they're also the frontlines of the solutions. They're the ones who are best positioned to protect our ecosystems -- including the soil, water, and clean air on which we all depend.

Finally, the authors emphasize the need for systemic change; that's the only way to address the roots of hunger and achieve this needed paradigm shift. Folks, this isn't about "tweaking" here and there; this is a call for a "transformation" at the heart of our food system.

The report includes a trove of data proving the benefits of this paradigm shift, especially as we face an increasingly climate unstable future. In a particularly interesting chapter, Professor Miguel Altieri highlights the growing evidence about the role of sustainable agriculture practices in fostering farm resilience in the face of major climatic events. All the results showed those farmers with greater biodiversity and other agroecological qualities fared significantly better post-natural disasters.

After Hurricane Mitch ravaged Central America, the Campesino o Campesino movement organized farmer research teams to evaluate the impact. They visited 1,804 farms in 360 communities in Guatemala, Honduras, and Nicaragua. What they found was astounding: Those farmers who had adopted sustainable agriculture practices retained greater soil moisture and 20 to 40 percent more topsoil; they also experienced less soil erosion and economic losses.

The report also highlights how agribusiness and chemical corporations have influenced policy setting, regulatory agencies, and research institutions, slowing the spread of more sustainable practices in agriculture. To give just one example, Marcia Ishii-Eiteman from the Pesticide Action Network of North America describes how chemical corporations have influenced national and international chemical policy.

For instance, after Malaysia passed a 2002 ban of the highly toxic chemical herbicide, Paraquat, its manufacturer Syngenta joined the country's palm oil industry to lobby to reverse the ban, which the government did in 2006. Today, Paraquat is still widely used there.

The report also makes it very clear how important it is to act now, because the very resources we depend on for food security are at stake: from a stable climate to abundant topsoil to accessible water. In chapter after chapter, the authors highlight the importance of embracing sustainable agriculture, not only to foster greater on-farm resiliency, but to preserve these vital natural resources.

Follow Anna Lappe on Twitter: www.twitter.com/annalappe

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