Popcorn: a matter of thermodynamics

Inside, a kernel of corn is soft because it contains the endosperm, which is made of starch and water, whereas the outer shell of the corn is very hard and, while it’s cooking, behaves like a pressure cooker. The heat, in fact, transforms a part of the water in hot steam, which increases the pressure between the kernel’s walls and dissolves the starch, turning it into a sticky jelly that is mixed with the remaining water. When the pressure inside the grain reaches more or less 9 atm (in a pressure cooker you get less than 2 atm), the outer shell explodes and all the water evaporates instantly, thus cooling the gluey starch which solidifies in the typical white foam.

Asked by captainblububbles


Fellow Canadians, wouldn’t it be awesome to be a coconut?
To live exclusively on the seashore, with an average annual temperature no less than 25°C and lots of sunshine and humidity? In the dead of winter, that sounds awesome. Then again, eventually you’d end up as the business end of some American girl’s Spring Break piña colada; the uncredited supporting character in the latest Girls Gone Wild video. Never mind, then.

If the extent of your coconut knowledge is pretty much summed up above (piña coladas, Bounty bars, going topless, etc.), then this post is totally going to blow your socks off. The humble coconut can do some pretty wild things.

Let’s start with coconut basics. First off, a coconut is not a nut. It’s a drupe. A drupe is a fruit where a thin skin (called the exocarp) and fleshy layer (called the mesocarp) surround the shell (called the endocarp), which has a seed inside. Some common drupes that you’ll be familiar with are peaches, plums, nectarines, cherries and pistachios.

“But wait!” you’ll say. “What are you smoking? Coconuts are nothing like plums!”
While that may appear to be true, that’s just because when you pick up a coconut what you’ve actually got is the pit (or seed) of the fruit. The flesh and skin are already removed and used for many other non-culinary purposes, like making rope, mats and upholstery.

So once you get into a coconut, what’s all that delicious and slightly sweet white “meat?” Don’t get grossed out, but it’s called “endosperm.” You might not realize it, but we use endosperm in all sorts of foods. Flour? That’s ground up wheat endosperm. The barley in your beer? Endosperm. Delicious popcorn? Well, that’s exploded endosperm.

For the plant embryo inside the coconut seed to grow, it needs fuel. The endosperm, made up of starch, protein and fat, provides that fuel. Coconut meat contains relatively less sugar and more protein than typical fruits (apples, bananas, etc.), but is very high in saturated fat. In fact, 90% of the fat found in coconut meat is saturated. That’s more than butter. That’s more than lard.

You know that coconut meat (and water) are tasty, and used in all sorts of baking. That’s not rocket surgery. But I promised to blow your minds about coconut, so let’s get down to the weird science.

A 2007 study done in rats with benign prostatic hyperplasia (BPH; uncontrolled growth of the prostate gland that leads to difficulty urinating) found that at doses of 400 and 800 mg/kg, coconut oil inhibited prostate growth by 61.5% and 82% respectively. It’s presumed this is because the high concentrations of fatty acids in coconut oil work to inhibit the inflammatory enzyme that causes BPH.

Even though it’s high in saturated fats, coconut oil has actually demonstrated beneficial effects on blood antioxidant and lipid levels in rats. A 2009 study concluded that high levels of polyphenols (antioxidants) in virgin coconut oil actually helped to keep blood cholesterol under control. The polyphenols in coconut oil are so effective that a 2010 study investigating their use as a novel cancer treatment found that they had significant toxic effect on cancer cells, but curiously (and amazingly) had no detectable toxic effect at all on normal cells.

And this is just totally wild: Because coconut seeds are completely sealed, their insides (including the coconut water) are sterile. The coconut water is also very close to isotonic, meaning that it has the same concentration of dissolved chemicals in it as human blood. This made coconut water a handy means of cleaning wounds in the field, and even emergency intravenous hydration, during World War II.

Because all of these coconut studies are still relatively new, I suspect we’ll be hearing a lot more about its medical applications in the near future. So next time you think of putting the lime in the coconut, consider that doctors may soon be putting the coconut in you!

What is up with the different kinds of bread?

The bread section of a store can be overwhelming because there are TONS of options to choose from! How can you pick your bread? Learn a bit about the different types mentioned below:

  • White bread: White bread is made from wheat flour, however the germ and bran are removed, leaving the endosperm. When the germ and bran are removed, fiber, vitamins B6 and E, magnesium, zinc, folic acid and chromium are all also lost. White bread is a lot less nutritious than whole wheat options due to the loss of these nutrients. Even though white bread is enriched, it does not contain nearly as many nutrients as orignial wheat bread does. According to Vegetarian Times, “there’s so little fiber left after processing that you’d have to eat eight pieces of white bread to get the fiber in just one piece of whole wheat bread.”

  • Wheat Bread: Wheat bread is not the same as whole-wheat because it could have been refined and lost many of its nutrients.

  • Whole Wheat Bread: Whole wheat is one kind of whole grain, so all whole wheat is whole grain, but not all whole grain is whole wheat.

  • Multi-Grain Bread: Mutli-grain bread is not necessarily healthy. While it may use different grains, they could be refined grains so it is not as healthy a choice as a 100% whole wheat/grain option would be. Check the ingredients to see which grains have been used in it.

  • Whole Grain Bread: Whole grain bread is made from whole wheat flour and it is processed including the endosperm, bran, and germ. Since it includes all of them, it contains more fiber, vitamins B6 and E, magnesium, zinc, folic acid and chromium and therefore is a more healthful option.

  • Sprouted Bread: Sprouted grain bread has a few advantages over whole wheat bread.Sprouted-grain bread is made from wheat kernels that have been sprouted, grounded and baked into bread.  This process retains more of the nutrients. Many sprouted grain breads contain legumes and a variety of healthy grains, providing a wider variety of nutrients and amino acids. Sprouted grains have also been said to be easier to digest than whole grains.

How to tell if it is vegan?

Unfortunately many brands are not! Breads often contain eggs, milk, honey, or other non vegan ingredients. While you could look through all of the ingredients or google to see if a brand is vegan, my favorite tool is an app called ‘Is It Vegan?’. I just recently discovered this app and it is amazing! You simply scan the barcode and it tells you which ingredients are/are not vegan! It is so helpful and perfect on the go tool for when you are shopping!

How to tell if bread is healthy?

The color and the name of the bread used to be a good determinant in whether bread was healthy, however it is not so true anymore. It is best to do some research on breads ahead of time to pick out a good one! My favorite is Ezekiel bread! You should definitely check the ingredients of the bread before buying it- many breads may say whole wheat but have enriched flour as one of the primary ingredients. Look for whole wheat or whole-grain flour listed first on the product’s ingredient list. Make sure that your bread or bread product says it is 100% whole wheat or 100% whole grain rather than just “wheat bread” or “multigrain bread”. So be careful and select a good brand for you! Another option would be to cook your own bread! There are tons of recipes out there so take a look!


Study solves plant sex mystery

A team of biologists from the University of Leicester has solved a mystery surrounding how plants have sex. The researchers have discovered a pair of proteins made by flowering plants that are vital for the production of the sperm present within each pollen grain.

Scientists already knew that flowering plants, in contrast to animals, require not one, but two sperm cells for successful fertilisation: one to join with the egg cell to produce the embryo and one to join with a second cell to produce the nutrient-rich endosperm inside the seed.

The mystery of this ‘double fertilization’ process is how each single pollen grain is able to produce twin sperm cells.

This breakthrough study from the Twell Laboratory at the University of Leicester, published in the prestigious academic journal The Plant Cell, has found a pair of genes called DAZ1 and DAZ2 that are essential for making twin sperm cells. Plants with mutated versions of DAZ1 and DAZ2 produce pollen grains with a single sperm that is unable to fertilize.

The researchers show that DAZ1 and DAZ2 are controlled by the protein DUO1 that acts as a ‘master switch’ - so that DUO1 and the DAZ1/DAZ2 genes work in tandem to control a gene network that ensures a pair of fertile sperm is made inside each pollen grain.

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Image credit: Jerome Twell


Scarification (botany): The process of damaging a tough seed coating to hasten germination. It can be accomplished with thermal stress, extended soaking, abrasion, or blunt force.

Many seeds will remain dormant for dozens of years without some form of scarification, because the seed coating forms a barrier that is impervious to both water and gasses, hermetically sealing the embryo.

I am using a small three-sided file to penetrate the tough seed coats of these Canna seeds from kihaku-gato (after failing with a hammer and a small knife). These seeds are so hard, that in India, they have been used as shot! After many strokes of the sharp edge of the file, the white endosperm peeks through.

#garden science #scarification #germination

How Leaf Veins Changed the World
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When we think of the dominance of flowering plants on the landscape, we usually invoke the evolution of flowers and seed characteristics such as an endosperm and fruit. However, evolutionary adaptations in the structure of the angiosperm leaf may have been one of the critical factors in the massive diversification that elevated them to their dominant position on the landscape today.

Leaves are the primary organs used in water and gas exchange. They are the centers of photosynthesis, allowing plants to take energy from our closest star and turn it into food. To optimize this system, plants must balance water loss with transpiration in order to maximize their energy gain. This requires a complex plumbing system that can deliver water where it needs to be. It makes sense that plant physiology should maximize vein production, however, there are tradeoffs in doing so. Veins are not only costly to construct, they also displace valuable photosynthetic machinery.

It appears that this is something that flowering plants do quite well. Because leaves fossilize with magnificent detail, researchers are able to look back in time through 400 million years of leaf evolution. What they found is quite incredible. There appears to be a consistent pattern in the vein densities between flowering and non-flowering plants. The densities found in angiosperm leaves both past and present are orders of magnitude higher than all non-flowering plants. These high densities are unique to flowering plants alone.

This innovation in leaf physiology allowed flowering plants to maintain transpiration and carbon assimilation rates that are three and four times higher than those of non-flowering plants. This gives them a competitive edge across a multitude of different environments. The evolution of such dense vein structure also had major ramifications on the environment.

This massive change in transpiration rates among the angiosperm lineage is likely to have completely changed the way water moved through the environment. These effects would be most extreme in tropical regions. Today, transpiration from tropical forests account for 30-50% of precipitation. A lot of this has to do with patterns in the intertropical convergence zone, which ensures that such humid conditions can be maintained. However, in areas outside of this zone such as in the Amazon, a high abundance of flowering plants with their increased rates of transpiration enhances the amount of rainfall and thus forms a sort of positive feedback. Because precipitation is the single greatest factor in maintaining plant diversity in these regions, increases in rainfall due to angiosperm transpiration effectively helps to maintain such diversity. As angiosperms rose to dominance, this effect would have propagated throughout the ecosystems of the world.

Photo Credit: Bourassamr (Wikimedia Commons)

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