Outstanding Osmosis, aka Gorgeous Gnocchi

Concentration is how much stuff is in one location. High concentration, lots of stuff. Low concentration, not a lot of stuff. When a substance can move freely it will move around until the concentration is equal all over (equilibrium). Gases, liquids, and solutions do this, which is why something cooking in your kitchen can smell wonderful in your living room. When there is a barrier, sometimes only very small molecules can make it across. When the molecule that makes it across is water it is called osmosis.

This is how boiling pasta works. You put something with out water into water and osmosis makes the pasta fill with water. Heat makes the molecules beat the surface of the pasta more often filling the dry pasta with water faster.

This is my twist on pasta, potato gnocchi. I was introduced to it this year and have fallen it love. It is lighter and fluffier than any other pasta and really simple to make yourself. It is for these reasons I contend that happiness is fresh made gnocchi on a rainy day (like today!). This recipe is from my mother's cooking class.

Potato Gnocchi

Ingredients

2 large Russet potatoes

1 large egg, beaten

1 Tablespoon butter

1/2 teaspoon salt

1/8 teaspoon pepper

pinch nutmeg

1+ cup flour

Preheat the oven to 425 degrees. Pierce each potato several times with a fork. Bake directly on oven rack for 1 hour. As soon as the potatoes are cool enough to handle, scrape the pulp into a medium bowl and mash with a fork. Blend in butter. Mix in egg until smooth. Stir in salt, pepper, and nutmeg. Work in about half of the flour with your hands until the dough becomes thick. Knead in the remaining flour and perhaps some extra until the dough is firm and no longer sticky. Divide the dough into quarters. Roll into a rope ~24" long, cut the dough into pieces about 1/2" wide. Press onto and roll across the tongs of a fork. In a large pot of boiling water (1 gallon/1 lb pasta, 2 Tablespoons salt/gallon), cook gnocchi until it floats. Drain completely, and toss with sauce and serve immediately.

Cancer Fighting Antioxidants aka Superhero Strawberry Rhubarb Pie

Cancer sucks, simple enough. This is a very important time of year for cancer for a couple of reasons. First the sun is coming out (sunscreen anyone) and second tonight is Georgetown University's Relay for Life. So here is my chemistry kitchen tribute to fighting cancer. This science comes from the most cited article in the Journal of Agricultural and Food Chemistry (Wang, H.; Cao, G.; Prior, R.L. "Total Antioxidant Capacity of Fruits." J. Agric. Food Chem. 1996, 44, 701-705.).

DNA is the stuff that determines our physical properties down to the cellular level. Every cell (except red blood cells) contain identical DNA that can replicate itself perfectly, for the most part. Cancer happens when something happens that changes the DNA and when it replicates (mutation). When the DNA replicates uncontrollably we get tumors. When the replication spreads, we get cancer. Any number of things can mutate DNA including chemicals and sunlight.

Electrons in a molecule are happiest paired. Oxidizing free radicals are chemicals that have unpaired electrons that remove electrons from atoms, especially oxygen, to make a pair. The atom then is forced to create different bonds to compensate for the lost electrons. DNA contains a lot of oxygen that can be affected by these free radicals. And when the free radicals react with DNA they can cause serious mutations. Antioxidants provide a different place to remove electrons from, keeping the free radicals from damaging the DNA. In the correct concentrations they can help prevent a number of diseases including cancer.

Drs. Wang, Coa, and Prior looked into which everyday foods have the most of these superhero chemicals. They tried strawberries, oranges, apples, grapefruit, plums, red grapes, white grapes, kiwi, bananas, tomatoes, pears, and honey dew along with orange juice, grapefruit juice, tomato juice, grape juice, and apple juice. Their conclusion, strawberries have the highest concentration of antioxidants by weight, and grape juice has the highest by volume of the juices.

So, one of the nice things about this time of year is that produce is starting to appear in grocery stores everywhere. Making it really easy to find all those cancer fighting antioxidants. And since strawberries are on the top of the good doctors' list, here is my take, strawberry rhubarb pie. The original recipe is from Bon Appetit (April 1997), I found the recipe on Smitten Kitchen (http://smittenkitchen.com/2008/05/strawberry-rhubarb-pie/) and made one major change. I replaced the lattice top with a crumb top. As one of my chemistry buddies said, "A lattice top looks pretty, but a crumb top tastes better." This is one of my dad's favorite pies, but as he says it isn't Strawberry Rhubarb Pie without vanilla ice cream, so be sure to serve it A'la Mode.

Strawberry Rhubarb Pie

Ingredients

Crust

1-1/2 cups flour

1-1/4 teaspoons sugar

1/4 teaspoons salt

1/3 cup vegetable shortening

5 Tablespoons butter

up to 5 Tablespoons ice water

Filling

3/4 lb chopped rhubarb

16 oz strawberries, hulled and halved

1/2 cup brown sugar

1/2 cup sugar

1/4 cup cornstarch

1 teaspoon cinnamon

1/4 teaspon salt

Crumb Topping

1 cup rolled oats

6 Tablespoons flour

1/2 cups brown sugar

1/4 teaspoon cinnamon

1/8 teaspoon nutmeg

8 Tablespoons butter

Combine flour, sugar, and salt. Cut in shortening and butter until a coarse meal forms. Add water 1 Tablespoon at a time, until the mixture forms moist clumps. Form into a ball and flatten into a disk. Wrap in plastic wrap and chill for 1 hour.

In a separate bowl mix together all of the filling ingredients.

In a separate bowl combine the oats, brown sugar, flour, cinnamon, and nutmeg. Blend the butter into the dry ingredients using your fingers until the mixture resembles course crumbs.

Preheat the oven to 450 degrees. Place the pie crust disk on a lightly floured surface. Roll out to a size sufficient to line a 9 or 10 inch pie pan. Line the pie pan with the crust, flute the edges. Pour in the pie filling. Sprinkle the crumb mixture over the top and bake for 20 min. Turn the oven down to 350 degrees and bake until golden brown and bubbly in the middle (25-75 minutes). Don't be afraid to over cook this one, the longer it is in the oven the thicker your filling will end up.*

*Some hints about pie: Fluting the pie keeps the pie crust from shrinking out of the pie pan. After the first 20 minutes, you may want to cover the pie with tin foil to keep the crust and topping from burning while the filling cooks. And be sure to put an old baking sheet on the rack below the pie to keep the drippings from hitting the burner and causing a smoke storm in your kitchen.

Being Exact, The Expert Effect

If you want to know the time, you check a clock. If you want to know where Angola is you ask the atlas. If you want to know how to spell disestablishmentarianism you discuss it with the dictionary. And if you want to know how chemistry works you consult any number of texts including the CRC Handbook of Chemistry and Physics (kind of a chemist's dictionary), textbooks, or scientific journals. To get my facts straight I have been using a pile of textbooks (see above) that I have collected throughout my studies.

They are great for long standing facts, but to get the most up to date information chemists turn to peer reviewed journals. These are essentially magazines where chemists specifically, and scientists in general, publish their most recent research. This is where the science headlines come from. The journals can be very broad like the Journal of the American Chemical Society (loving referred to as JACS). Or they can be very specific like the Journal of Agricultural and Food Chemistry, which is also published by the American Chemical Society. To be published by one of these journals is a big deal for a chemist. It is proof that what you are doing is relevant, important, and correct. And for many being published that first time marks the transition between being a chemistry student and being a chemist.

From time to time I'll be turning to the front pages of these journals for inspiration. So be prepared, at times we are going to be on the cutting edge. And as always, I'll be figuring it out right along with you.

Cornstarch Crystal Conundrum aka Perfect Pudding

Cornstarch is very important to any cook or baker who has ever tried to thicken a filling or a sauce. It is effective and highly water soluble, so the resulting product doesn't look milky or cloudy like sauces thickened with roux can. It is a starch, which is a very long carbohydrate. Carbohydrates, after a long and extensive and way too complicated chemical reaction, are what provide energy for our bodies. Starches are produced by plants as a way to store the carbohydrates. Cornstarch is, believe it or not, a starch produced by corn.

Atoms consist of a nucleus (protons and neutrons) and an electron cloud. The number of protons in a nucleus determines what type of atoms they are. There are lots of ways that atoms interact with each other. When they get close enough that they share their electrons they are bonded and they become a molecule. These molecules in turn can react with each other and create much weaker bonds called intermolecular bonds. The strongest intermolecular bond is the hydrogen bond. When a hydrogen is bonded it loses it's electrons. Some atoms, like oxygen (and nitrogen), keep their electrons. So when a lot of molecules get together, the hydrogens and oxygens (or nitrogens) will try to pack close. Pure starches bond really closely to each other through these hydrogen bonds and the resulting groups are called crystals.

So what happens when you throw some of this starch in a pot with water and heat? The heat makes the molecules dance (more heat = more energy, more energy = more dancing), the faster they dance further they get away from each other. When they get far enough away the crystals break and the water rushes in and takes up the hydrogen bonding spots. The water get pulled in very tightly making it harder and harder for the water to move around, thickening the mixture.

Pudding is one of the many excellent foods that uses this reaction to its advantage. The other day I found myself craving something sweet. And pudding, homemade from scratch pudding, was what fit the bill. Or more accurately, what fit the current state of my pantry. Actually that isn't really true. I had to make some modifications to make this recipe work, and boy were they delicious. I was out of white sugar, so I used brown sugar instead. The original called for finely chopped bittersweet chocolate, all I had was chocolate chips. And like every other recipe I make I added a little extra vanilla. The original is by Martha Stewart. This is my version.

Comfort Chocolate Pudding

Ingredients

6 Tablespoons brown sugar

3 Tablespoons cornstarch

1-1/2 Tablespoons cocoa powder

pinch salt

1-1/4 cup heavy cream

1-1/4 cup milk

1-1/2 teaspoon vanilla

1 cup chocolate chips

1-1/2 Tablespoons butter

In a medium saucepan, whisk together sugar, cornstarch, cocoa, and salt. In a small bowl combine the cream with the milk and vanilla. Whisk some of the cream mixture into the dry ingredients until cornstarch is completely dissolved. Whisk in remaining cream mixture until smooth.

Place saucepan over medium heat. Cook, whisking constantly, until mixture comes to a boil and thickens (this will happen at about the same time so keep an eye on it). Remove from heat and add chocolate chips, whisking until chocolate is melted. Whisk in butter until melted.

Using a ladle, pour pudding into six dessert cups. Refrigerate until set, about 1 hour.