Chemical magic in the mouth

Scientists in Switzerland are reporting that bacteria in the human mouth play a role in creating the distinctive flavors of certain foods. They found that these bacteria actually produce food odors from odorless components of food, allowing people to fully savor fruits and vegetables. Their study is scheduled for the November 12 edition of the ACS bi-weekly Journal of Agricultural and Food Chemistry.

In the study, Christian Starkenmann and colleagues point out that some fruits and vegetables release characteristic odors only after being swallowed. While scientists have previously reported that volatile compounds produced from precursors found in these foods are responsible for this ‘retroaromatic’ effect, the details of this transformation were not understood. To fill that knowledge gap, the scientists performed sensory tests on 30 trained panelists to evaluate the odor intensity of volatile compounds – known as thiols – that are released from odorless sulfur compounds found naturally in grapes, onions, and bell peppers. When given samples of the odorless compounds, it took participants 20 to 30 seconds to perceive the aroma of the thiols – and this perception persisted for three minutes.

Volatile sulfur compounds have a low odor threshold, and their presence at microgram per kilogram levels in fruits and vegetables influences odor quality. Sensory analysis demonstrates that naturally occurring, odorless cysteine-S-conjugates such as S-(R/S)-3-(1-hexanol)-l-cysteine in wine, trans-(+)-S-1-Propenyl-L-cysteine sulfoxide in onion, and S-((R/S)-2-heptyl)-l-cysteine in bell pepper are transformed into volatile thiols in the mouth by microflora. The time delay in smelling these volatile thiols was 20-30 s, and persistent perception of their odor occurred for 3 min. The cysteine-S-conjugates are transformed in free thiol by anaerobes. The mouth acts as a reactor, adding another dimension to odor perception, and saliva modulates flavors by trapping free thiols.

The researchers also determined that the odorless compounds are transformed into the thiols by anaerobic bacteria residing in the mouth – causing the characteristic ‘retroaromatic’ effect. “The mouth acts as a reactor, adding another dimension to odor perceptions,” they explain. However, the authors conclude, it is saliva’s ability to trap these free thiols that helps modulate the long-lasting flavors.

What Is Teflon?

You go shopping with your mother for a non-stick pan! Your mother plans to prepare some pan cakes and you watch her prepare it for you. You anticipate that the dough when poured on the pan is sure to stick and your mother is going to have a hard time taking it out.

However, when your mother pours the dough, to your surprise the pan cake comes out clean without even a piece sticking to the pan. You wonder if this is some kind of magic! This is definitely the magic of Teflon!There is a coating on the surface of every non-stick pan. It is called as Teflon. This coating prevents the food from sticking to the utensil.

What is Teflon?
Teflon was invented in the year 1938 by Dr. Roy Plunkett at DuPont’s Jackson Laboratory while trying to invent a new refrigerant. During the experience, Dr Roy Plunkett happened to create a compound that gas polymerized while it was stored. What came out was a solid, waxy and super slippery substance.

Dupont Laboratory got a patent for this substance in the year 1940. However, they did not use it till 1950s. Post that, the coating was used on cookware and soon the products improved and today they are more durable as compared to any other cookware.

It is a substance called as polytetrafluoroethylene (PTFE). This is considered as the most slippery substance that ever exists. Teflon is a fluroplastic that is odourless and colourless powder with many properties that will give you many uses.

How is Teflon coating done?
Teflon is applied to the pots and pans in a multi-step process to make sure that the material sticks to the surface of the utensil. The first layer is a sticky molecule that is applied to the surface of the utensil. This is followed by the application of a non-stick surface and is followed by a final coating of non-stick Teflon and a combination of other hardeners.

Teflon being an inert substance is considered safe for cooking. Teflon coated products have made cooking easier and less messier as compared to earlier times.

While cooking on a PTFE coated utensil, here are some things you need to remember. Always use plastic or wood utensils on Teflon coated cookware as metal stirrers will scrape away the Teflon coating and harmful fumes may arise from the scratched area as you cook on fire.

While washing Teflon cookware use only soft sponges or brushes with soft bristles to avoid scratches. In case there is burnt food that is stuck to the utensil, loosen them by soaking the utensil in water overnight instead of trying to scrub them out.

Avoid leaving Teflon coated utensil unattended on a flame as too much of heat can lead to melting of the coating and the fumes may prove harmful to our health. Wash Teflon coated utensils by hand and avoid putting them in the dishwasher as this can spoil the coating on the utensil.

How to Froth Milk by Hand?

When you go to a coffee shop, do you wonder how they make those pretty patterns on the coffee froth? An automatic milk frother can be quite expensive. And did you ever wonder why you get a thick froth in the shop coffee, but just a thin one at home?

Why does milk froth?
When boiling milk, it forms a thin frothy layer on top, which expands like a balloon. Why
does this happen?

Milk is a complex liquid, with fats, proteins and sugars in it. The main protein of milk is casein. It is a long, string like molecule, which is folded up tightly, just like a ball of wool. Casein is very good for health because it’s a complete protein. That means it has all the 20 amino acids the body needs for growth.

Amino acids come in two types. Some of them dissolve in water easily, while some don’t like water (The chemical word is ‘hydrophobic’, which is Greek for ‘water-hater’!). Normally, the water-hating amino acids are inside the tightly wound up string. When boiling milk, the casein unwinds, and all amino acids face the water. At this time, it acts just like soap, with parts that dissolve in water, and parts that repel it. And that’s why milk froths – because of its soap like casein!

Making froth in a latte
When you order a latte or a cappuccino in a coffee shop, look carefully at the barista
(that’s the guy that makes the coffee). He’ll take a little coffee brew in a cup, add a spot of milk and then place it in front of the coffee machine. The machine shoots a jet of steam into the coffee. The steam stirs up the milk and makes it froth. The more you stir it, the frothier the coffee becomes. This is because the bubbles of steam are really very tiny.

The same thing happens when you blow soap bubbles. But because you blow a lot of air from your breath, the bubbles are big. When you beat eggs in a bowl, the air from above gets beaten into the egg, forming small bubbles.

Latte Art
So how does the barista make those pretty patterns? That’s where the chemistry comes in.
Milk, foam and coffee broth are colloids. A colloid is a material in which two materials that normally don’t mix are forcibly mixed. Foam is a colloid of air in water. Milk is a colloid of milk fats in water, held together by the casein. The coffee broth is a colloid of coffee oil in water.

What the barista does is to mix these colloids around very carefully, by drawing the foam over the coffee broth and milk. If you leave the colloid alone, it’ll stay for a while. If you stir your latte, the colloids will break up.

How does popcorn pop?

The sound of popcorn popping is almost as much fun as eating it. No wonder it is the most popular snack at movie halls and homes around the world. But what makes it pop in this unique way? Let’s read on.

First, where did popcorn originate?
No one knows exactly where popcorn came from or when it was first popped, but
archaeologists have found popcorn in some unusual places. One such place was the tombs on the east coast of Peru where they found grains of popcorn that were a 1,000 years old. These grains were so well preserved that they still popped!

Ears of popcorn were also found in the Bat Cave of West Central New Mexico that were nearly 5,600 years old. One of the oldest finds of popcorn was made in Mexico City where 80,000-year-old fossilized corn pollen was found buried 200 feet below the city! Archaeologists believe that popcorn originated in Mexico, but they know that it was grown in China, Sumatra, and India years before Columbus visited America!

So just how does popcorn pop?
Well, only popcorn kernel (the seed-like corn piece) can pop, and the secret is water. Each
kernel contains a small amount of water stored in a circle of soft starch inside the hard outer casing. When heated to around 450 degrees F, the moisture turns to steam, creating pressure within. As the pressure builds, the casing eventually gives way, and the kernel explodes and pops, allowing the water to escape as steam and turning the kernel inside out. If you have ever popped popcorn, you know that it explodes everywhere!

To keep popcorn from exploding everywhere, modern popcorn poppers usually have some way to keep the popcorn contained. Most poppers are covered in some fashion, but the ways of popping popcorn differ greatly. There are air poppers, poppers made for the fireplace, bags designed as poppers for the microwave, foil pans designed for the stove top, and various machines that use heat and oil. Even though our methods of popping popcorn may differ, they really are not that different from long ago.

Archaeologists have found ancient popcorn poppers on the north coast of Peru that date back to the pre-Incan Mohica Culture of about 300 AD. These poppers were usually shallow bowl-like containers with a hole on top and a single handle. They were sometimes decorated with a sculptured or printed motif such as a cat. However, you didn’t always even need a popper, as shown by some Native Americans who just spread oil on an ear of popcorn and laid it near a fire. The kernels would pop attached to the ear, and it was even eaten similar to corn-on-the-cob.

Now you know the story of pop corn, go ahead and pop some and have fun!

Is It Safe To Eat Chocolate That Has Turned Grey?

Imagine all the different types of delicacies made of chocolate; chocolate bars, chocolate fudge, chocolate cake, chocolate chip cookies, chocolate ice cream, chocolate milk, chocolate cereal, hot chocolate, chocolate sauce… the list is endless. But have you ever seen this wonderful treat turn grey?

The grey effect
There’s nothing quite like opening a much-anticipated box of chocolates only to find that
it is discolored and slightly grey. When chocolate turns grey like that, one of two things could be the reason: sugar bloom or fat bloom.

Sugar bloom is normally caused by surface moisture. The moisture causes the sugar in the chocolate to dissolve. Once the moisture evaporates, sugar crystals remain on the surface. If this process is repeated, the surface can become sticky and even more discolored. Although sugar bloom is most often the result of overly humid storage, it can happen when the chocolate has been stored at a relatively cool temperature and is then moved too quickly into much warmer surroundings. When this happens, the chocolate sweats, producing surface moisture.

Fat bloom is similar to sugar bloom, except that it is fat or cocoa butter that separates from the chocolate and deposits itself on the outside of the candy. As with sugar bloom, the most common causes of fat bloom are quick temperature changes and overly warm storage.

Although it might look a little less appetizing than a lustrous, rich chocolaty-brown piece of candy, it is still okay to eat. You may find the texture of sugar-bloomed chocolate to be a bit grainy on the outside, but it should still taste good.

Tips to preserve it
To prevent chocolate from graying, simply use proper storage methods. Since it can easily
absorb flavours from food or other products situated nearby, it should be tightly wrapped and stored away from pungent odours. The ideal temperature for storage is between 65 and 68 degrees Fahrenheit (18 to 20 degrees Celsius), with no more than 50 percent to 55 percent relative humidity. If stored properly, you can expect milk chocolate and white chocolate to be good for up to six months. Other types of chocolate can have an even longer shelf life.

So go ahead and gorge on those wonderful goodies to your heart’s content. Just make sure you don’t overeat, because even though grey chocolate is not bad, too much of any chocolate can make you fall sick. Take care and have fun.

How to get rid of garlic’s pungent smell?

Everyone relishes garlic bread but even one bite later you realize that not just your mouth but even your sweat smells funny!  In fact, even our burps emit a foul smell after we consume garlic in our food. Why is it that in spite of using so much of deodorant our body emits a foul smell especially when we consume garlic! Let us find out why this happens…

The cause of foul smell
Garlic is made up of sulphuric compoundsthat render the pungent smell to it. Also, when we put garlic in our mouth, it encourages the growth of certain bacteria that is already present in our mouth. This leads to bad breath.

Garlic contains allyl methyl sulphide, which is the reason for the pungent smell. It passes into our blood stream during the digestion process. Once it is in our body, it gets to the pores of our skin and when we sweat, it gets expelled and causes the sweat to smell. The allyl methyl sulphide also enters our lungs and contaminates the air inside. As we breathe, the air enters our lungs, gets contaminated and comes out as we exhale. This is why our breath smells.

The effect of this chemical lasts for few hours but the bad breath and body odour will continue till it is completely thrown out of our system by way of sweat or excreta.

How to get rid of the smell
Brush your teeth and wash your mouth with a good mouthwash to kill the triggered bacteria that adds to the foul smell.

Have a good shower to wash off the stinky sweat.

Dab your skin with some good smelling powder or deodorant to keep the smell away.
Research has shown that drinking milk helps bring down the effect of garlic in our blood stream and thus reduces the odour from reaching the lungs.

Another way to reduce the effect of garlic is to have parsley and sprigs. This is the reason why parsley and sprigs are combined with garlic in many of the exotic food preparations.

As the saying goes, prevention is better than cure, it is always better to stay away from garlic if you do not wish to smell “garlicky”. Or else the next time, you decide to have anything garlicky, be prepared to drink milk to bring down the effect of the same.

The Importance Of Calcium To Teeth

Each one of us has grown up listening to our mother’s telling us about the benefits of milk. When one talks of milk, the first thing it gets associated with is calcium. Milk is considered as an essential source of calcium. But is calcium really important to our body and especially our teeth?

Calcium deficiency does lead to dental and bone problems. Very few of us are aware that teeth are also bones. About one third of our bones and teeth are made of calcium. That is why drinking milk is important because you need the calcium from the milk to grow and maintain your bones and teeth.

Calcium is a vital mineral that our body requires on a daily basis. However, our body cannot produce this nutrient on its own. So, it relies on the food that we eat. Calcium is important for the functioning of the nerves, muscle contractions, which includes our heartbeat, and for cell division. The cells of our body that carry nerve impulses also need this essential nutrient. Calcium also acts as an enzyme activator in our body.

Calcium is important for the entire skeleton including our jawbone. It strengthens our jawbones and makes our gums healthy. Calcium rich body prevents tooth decay and it definitely helps in providing a great smile that can be considered as the biggest asset in our life.

Milk and dairy products are natural and the most concentrated source of calcium. Only during our developmental ages, calcium gets deposited on our bones and teeth. Once the development is done, the deposition stops. Hence it is necessary to get enough calcium through our diet in the early years of our life. If teeth are deprived of calcium they start showing signs of cavities and we end up with dental carries.

So, next time your mother scolds you for not having your routine cup of milk, take her words seriously and ensure that your body gets its usual quota of calcium.

The Facts About Birthday Candles

If it’s your Birthday, you have to blow all the candles lit on the cake as a ritual. But the situation is a little different when it comes to magic candles. The more you blow them the more they relight. Is this magic or simply chemistry? Let’s find out!

The trick
Every candle has a wick to burn. The difference between a normal candle and a trick candle is what happens when you blow it. When you blow a normal candle, a thin ribbon of smoke rises from the wick. This is nothing but vaporized candle wax. The wick is hot enough to vaporize the paraffin of the candle but not hot enough to re-ignite the blown candle.

Trick candles work a little differently from a normal candle. The wicks of this candle have a special material, which ignites at a relatively low temperature. When you blow a trick candle, the left over heat from the wick re-ignites this special material and the candle starts burning again. The flame that burns after blowing out the trick candle is burning paraffin vapour.

Meet the special material in trick candles
All candles are made out of paraffin wax (its CAS number is 8002-74-2) or candle wax as we call them. The special material added to the wick of trick candles is usually flakes of magnesium. Magnesium doesn’t require too much heat to start burning, just 800 to 430 degrees. The magnesium flakes start burning when you blow out the candle and ignite the vaporised paraffin. When you blow out the candle, the magnesium flakes appear as tiny particles on the wick and the magic begins.

One particle is enough to re-start the spark and in turn re-ignite the vaporised paraffin. The magnesium in the rest of the wick does not burn as the liquid paraffin separates it from oxygen and keeps it cool.

There is nothing magical about trick candles; just pure chemistry. So the next time you blow out a magic candle, you know why the flames reappear!

Why Do Onions Make Us Cry?

The mere thought of chopping onions can literally make you cry. But the moment your knife touches the onion, your eyes start burning and you have tears in your eyes. Here’s why it happens.

What do onions contain?

Onions contain amino acid sulfoxides that form sulfenic acids in the onion cells. Both the enzymes and the sulfenic acids are kept separately in the cells. When you cut the onion, the otherwise separate enzymes start mixing and produce propanethiol S-oxide, which is a volatile sulphur compound that starts wafting towards your eyes. The gas that is emitted reacts with the water of your eyes and forms sulphuric acid. The sulphuric acid thus produced causes burning sensation in your eyes and this in turn leads to the tear glands secreting tears. Thus you end up with watery eyes every time you cut onions at home.

It is the sulphur compound in the onions that also leave a typical odour of onions on your hands and utensils even after washing.

Tips to avoid the tears:

Make sure that you keep your fans off while cutting onions. If it is running, the air is on constant circulation, which will lead to the spread of gas and increase the burning sensation in your eyes.

Refrigerate the onion before cutting. By refrigerating, you freeze the enzymes from mixing with the sulfenic acids and the production of propanethiol S-oxide is stopped. As a result, sulphuric acid is not formed when you chop the onions. Wear safety goggles while chopping onions. It is also a good idea to keep away the gas from reaching your eyes.

Cooking the onion inactivates the enzyme. So cook the onion after you de-skin and before letting the knife touch the onion. Soak onions in water before cutting. Water absorbs the gas and you can avoid the tears.

Lighting a candle or a lamp near the chopping board is another effective way to avoid the tears. When a candle is lit near the chopping board the gas that is emitted from the onions get drawn towards the flame of the burning candle or lamp and it does not reach your eyes.

Avoid cutting the onion till the root. This will prevent the mixing of enzymes with the sulfenic acids and you can spare your eyes of the burning sensation and tears.

Tips And Hints Of Beating Egg Whites

Certain dishes require beaten egg whites, but do not avoid these for fear of failing to properly whip the whites. Although it seems like it should be a simple task, one of the most difficult things for some cooks to do is to whip whites into a stiff foam or froth.

Meringues and sponge cakes rely on stiffly beaten whites for their fluffy airy texture, so creating the correct foam structure is important for almost any baker. Improperly whipped whites do not hold their form and detract from the finished texture of the dish, but when done correctly, beaten eggs add lift and body to souffles, meringues and Angel food cakes.

Preparing Bowls and Beaters
For the absolute best and easiest results when whipping egg whites, go for the best equipment. Use only metal bowls, preferably straight-sided deep-copper or steel bowls. Opt for a copper bowl if beating the eggs by hand. Wash and thoroughly dry the bowl, beaters or whisk. Remove all soap, water or grease residue in the bowl; all of these prevent the eggs from properly whipping.

Cleanliness
Wash and dry your bowl and whisk or beaters until they are spotless and bone dry. Any hint of grease or oil will prevent egg whites from reaching their peak. Separate your eggs carefully to make sure there isn’t even one spot of egg yolk in with the white, as yolks have fat that will prevent the foaming from happening. Egg whites are more likely to whip well at room temperature so don’t attempt this with cold eggs or a cold bowl. Leave your eggs out on the counter for half an hour until they reach room temperature.

Additives
Add a pinch of salt to the egg whites as you begin to whip them. This will help the protein in the whites to become more firm, holding whipped peaks better. After you have whipped the whites for about a minute add a small bit of cream of tartar or 2 drops of triethyl citrate (sometimes known as Citric Acid Mono, the CAS number is 1587-20-8) or vinegar. This acid will help the bubbles from popping when you stop beating the egg whites.

Beating
Set the electric mixer, fitted with a balloon whisk, on medium speed until frothy. Add cream of tartar at this point, then increase the speed to medium high until soft peaks form. Use high speed only if firm or stiff peaks are desired. Wait to add extracts until the desired peaks begin to form. These machines can whip egg whites faster than any human arm can possibly do, adding more air to the mix and creating much more foam. Follow the directions outlined in the recipe for when to add sugar to the egg whites.