Tag Archives: flavor

Tongue.

The human tongue can actually ‘smell’ things

New research shows that the senses or taste and smell are much more intertwined than we’ve previously thought.

Tongue.

Image via Pixabay.

A team of researchers from the Monell Center report finding functional olfactory receptors — the sensors that detect odors in the nose — in the taste cells of our tongues. The findings suggest that the interactions between smell and taste, both of which comprise flavor, may actually begin on the tongue and not in the brain.

Smelling strawberries

“Our research may help explain how odor molecules modulate taste perception,” said study senior author Mehmet Hakan Ozdener, MD, PhD, MPH, a cell biologist at Monell.

“This may lead to the development of odor-based taste modifiers that can help combat the excess salt, sugar, and fat intake associated with diet-related diseases such as obesity and diabetes.”

You know how we recognize that something smells like strawberries, even though strawberries themselves don’t have a smell when you sniff them? This shows you how smell helps create flavor.

The sense of taste handles sweet, salty, sour, bitter, and umami (savory) molecules on the tongue. It evolved as a quick way for our brains to figure out how nutritious something we’re chewing on is, and make sure it’s not toxic or poisonous. But smell, too, was an important part in detecting the next snack. A pear and an apple taste pretty much the same if you hold your nose while eating. What our brains do when we eat something is to combine taste and smell, alongside information from other senses, to create what we perceive as flavor.

Common wisdom held that information from taste and smell stays separate until reaching the brain. However, Ozdener realized no one has previously checked this assumption. He thought of this when when his 12-year-old son asked him if snakes extend their tongues so that they can smell. So, alongside colleagues at Monell, Ozdener set about culturing living human taste cells.

After developing the techniques that would allow them to maintain such a culture, the team probed the cells, finding many of the molecules present in human olfactory receptors. Next, they employed calcium imaging to show that these cells respond to odor molecules in a manner similar to olfactory receptor cells. Taken together, the data points to olfactory receptors playing a role in our taste systems — possibly by interacting with taste receptors on the tongue. Other experiments by the Monell scientists demonstrated that a single taste cell can contain both taste and olfactory receptors, which supports the present findings.

“The presence of olfactory receptors and taste receptors in the same cell will provide us with exciting opportunities to study interactions between odor and taste stimuli on the tongue,” said Ozdener.

The findings help us better understand how smell and taste interact. However, they could also better inform us about either of those senses individually. We still don’t know, for example, what compounds activate the vast majority of the 400 types of functional human olfactory receptors. The cells cultured by the team, which respond to odors, could be used to screen molecules that bind to such receptors.

The paper “Mammalian Taste Cells Express Functional Olfactory Receptors” has been published in the journal Chemical Senses.

Cheese.

Novel approach to identifying flavor molecules poised to make fermented goods even more delicious

The Germans are coming for your cheese! They want to make it tastier!

Cheese.

Image credits Corinna Barbara.

Researchers from the Technical University of Munich (TUM), the Leibniz-Institute for Food Systems Biology, and the University of Hohenheim have developed a new technique for identifying flavor-bearing protein fragments in fermented foods such as cheese or yogurt. They hope that their findings will form a launchpad from which to upgrade the tastiness of a wide range of foodstuffs.

Cheesy business

Just like everything else, fermented foods draw a lot of their taste from volatile aromatic compounds. Unlike most other things, however, the flavor profile of items like cheese, yogurt, beer, or soy sauce also depends heavily on non-volatile substances (i.e. things you can’t smell). Some of the most important compounds that fall under this category are fragments of (originally-long) proteins broken down by bacteria during fermentation of milk or grains.

Still, there’s a lot of these fragments out there — over 1000 have been documented to impart flavor in fermented-milk products alone. Even worse, they take a whole lot of time and effort to discover. To work around the issue, a team led by Thomas Hofmann, head of the Chair of Food Chemistry and Molecular Sensory Science at TUM, has developed a new method to discover these tasty bits.

The team combined existing methods of proteome (protein) research with methods of sensory research to quickly and efficiently identify the most flavorful protein fragments in a given sample. The team tested their procedure on two varieties of cream cheese — which had different degrees of bitterness. The goal was to identify exactly which protein fragments gave the cheeses their bitter off-taste.

“We coined the term ‘sensoproteomics’ for this type of procedure,” said Andreas Dunkel from the Leibniz-Institute for Food Systems Biology, lead researcher for the study.

An initial review of the literature on the subject told the team that there would be roughly 1,600 different protein fragments that could create a bitter off-taste in dairy products. Chromatography-coupled mass spectrometer analysis in tandem with computer simulations narrowed the search down to 340 potential candidates. Comparative spectrometric, sensory, and quantitative analyses further reduced the number of fragments responsible for the bitter cheese flavor to 17.

“The sensoproteomics approach we have developed will, in the future, contribute to the rapid and efficient identification of flavor-giving protein fragments in a wide range of foods using high-throughput methods—a significant help in optimizing the taste of products,” says Prof. Hofmann.

The paper “A New Approach for the Identification of Taste-Active Peptides in Fermented Foods” has been published in the Journal of Agricultural and Food Chemistry.

Image Credit: Pixshark

What makes indian food so unique – a molecular explanation

After they analyzed more than 2,000 traditional Indian recipes down to the molecular levels, scientists now think they know what makes Indian cuisine so appealing. Unlike western dishes, Indian recipes are based on ingredients whose flavors don’t overlap, for a unique taste that dumbstrucks anyone who tries it for the first time.

Image Credit: Pixshark

Image Credit: Pixshark

Many who try Indian food never look back, and it’s easy to understand why. It’s seductively delicious because of a unique approach to flavoring. On average, a traditional Indian dish has at least seven ingredients that often have various flavors and/or spicings that are heterogeneously combined, so that each bite or mouthful can reveal different combinations of flavor elements that burst upon the tongue at different times in the chewing process.

Let’s take a moment to understand how flavors work their magic, first. Flavor is a sensory impression the brain registers when our chemical sensors (taste and smell) interact with substances (food). Of the chemical senses, by far the most important is smell. Taste is limited to sweet, sour, bitter, salty, umami, and fat since most recently. As previously reported the odors of food can be limitless in combinations, though. To make food taste interesting or avoid making it taste awful, chefs advise you use ingredients which have the right amount of flavor compounds (specific chemicals) in common. Chocolate and blue cheese might sound like a bad idea, but if mixed well to share the optimum amount of flavor compounds, it’ll taste great.

Indian cooks know spices. They use a large amount of a large variety of spices and their cooking techniques maximize the flavor in the final product. A skilled Indian cook uses spices like a painter who uses colors that they have grown to be very comfortable with. Image: Malabar Spice

Indian cooks know spices. They use a large amount of a large variety of spices and their cooking techniques maximize the flavor in the final product. A skilled Indian cook uses spices like a painter who uses colors that they have grown to be very comfortable with. Image: Malabar Spice

On average, there are just over 50 flavor compounds in each food ingredient and this interactive chart made by Scientific American will show you which ingredients mix well together, according to Western cuisine by overlapping flavors. Roasted beef works good with coffee or caviar. In fact, roasted beef seems to work well with anything. Asian cooking,however, is different – it works with congruous ingredients.

Researchers at the Indian Institute for Technology in Jodhpur scrapped thousands of recipes from a popular website, broke each to its constituent ingredients, then by flavors for each item. They found that rarely do the dishes share common flavors. Here’s an example for a random recipe.

recipe1

Each ingredient has its own flavor makeup which can be dozens in number. Coconut and onions don’t mix, as we all know, but some chemicals inside do.

recipe2

How often do you see coconut and onion in a Venn diagram?

So any two ingredients can pair up.

recipe3

Ultimately, some 200 ingredients were mapped in their database. What they found is that  Indian cuisine tended to mix ingredients whose flavors don’t overlap at all.

“We found that average flavor sharing in Indian cuisine was significantly lesser than expected,” the researchers wrote in Nature.

What’s interesting is that this trend is intensified when certain spices are used. A prime example is  cayenne, a basis for curry. When cayenne is added to dishes, the researchers found that these are likely to use ingredients with less flavors in common. In similar vein are green bell pepper, coriander and garam masala.

So, what you might want to do next time you’re making dinner is be a bit creative. Don’t get sidetracked by seemingly incongrous ingredients. Work it out. Who knows what you’ll invent. And don’t be afraid of curry. Bon Appétit!