Recent Recipes

Roasted Radishes


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Yesterday was the first box of our CSA season! Among other things, it contained radishes and fresh oregano! I promised to post one of my very own recipes soon (not just those recipes from other bloggers I've reviewed), so here we go! 

Fresh radishes means roasted radishes for dinner! They're quick to throw together, and then you can go do something else (like an inorganic test!) while they're baking. If you don't have a spastic oven like mine, they don't take that long, either. They go well as a side to almost anything. We had ours with corn, stir fried green garlic, tomato and new onions, and fried eggs.

Roasted Radishes
Servings: 1

          7 or 8 medium-small radishes
          1 1/2 teaspoons olive oil
          1 tablespoon shopped fresh oregano
          1teaspoon fresh ground pepper
          1/2 a teaspoon salt (or 1/4 teaspoon, if you're a more reasonable person than I am)
          1 teaspoon sugar
          dash lemon juice
          1 1/2 teaspoons balsamic vinegar

Heat oven to 400F

In a small baking dish, toss radishes with olive oil pepper, oregano, lemon juice and balsamic vinegar. Cover with aluminum foil and place in oven for 15-20* minutes, until radishes soften but are still firm in the middle.

Take radishes out of the oven. Sprinkle sugar over radishes and return to the oven uncovered for about 20-30* minutes, or until the radishes look well roasted, with a bit of crisp, caramelly-sugar covering them. Take out of oven, sprinkle with salt and serve.

*these cooking times are rough estimates; my old oven has a very uneven gas flow, and so the temperature is wont to vary widely while cooking.

Delicious! Mine didn't brown as much as I'd like, but I had a meeting to get to so I was running short on time. You might want to leave yours in the oven a little longer to brown, if you like that sort of thing.

As a chemistry aside, remember how I said we had these with fried eggs? For the first time ever while frying eggs, I noticed these funny little bubbles welling up inside the yolks:

(Ignore the massive hunks of ground pepper... it's an addiction.) Curious as to what these bubbles were, I looked up the contents of egg yolks. I was pretty sure these were actual bubbles and not part of the egg yolk which separated while it was still a liquid because of how they flitted around and... bubbled... so much. Incidentally, egg yolks are about half water (52.31g of water per 100g of egg yolk, according to wikipedia), so these bubbles are actually gaseous water--steam, basically. The really interesting part is how we only get a few bubbles in the yolk, if so much of it is water. There's actually a really simple reason, but I found it exciting. 

You don't see a giant buildup of gas largely because the membrane on an egg yolk is permeable to gases.  However, if we lost all 50% of egg yolk mass to volatilizing the water in the yolk, the membrane wouldn't be able to release the gas fast enough and the yolk pop after the pressure got high enough, just like those obnoxious bubbles that form between the bottom of the egg white and the pan and pop--spurting hot oil/butter all over you--when frying eggs. Incidentally, this is also caused by volatilized water. The water in direct contact with the pan (i.e, at the bottom of the egg) heats the fastest and then gets trapped between the egg and the pan until it has enough pressure to pop its way out along the side. (Yay thermodynamics!) 

Anyway, back to the yolk: instead of losing all or most of the water in the yolk, we first lose a little bit. After that water is volatilized and taken out of the fatty-acid, egg-yolk solution, the solution is concentrated. That is, there are more fatty acids per a unit of volume. The fatty acids look something like this:

Where the black, white-dotted chains are CH2CH2CH3 chains, mostly. There could be some double bond scattered about. Those red dots are oxygens which are making up the carboxylic acid part of the fatty acid.  That carboxylic acid group is the really polar part of the fat. 

Polar parts like to stick together. Water's polar, so that means the water's going to want to stick around those little polar tips way more than the black bits. 

The black bits, however, also do not want to be near the water. So these things tend to ball up into a sphere with all the black ends pointing inwards toward each other, and all the red ends pointing out. These are called micelles, and if I were an experienced blogger, I'd have an image for you. But I already took the fatty acid image from wikipedia, so that's enough photo-theft for today. Anyway, the waters cluster around those little red-dot-encased spheres, but there are a whole lot more waters than there is space around that sphere normally. 

However, when you boil away some of those waters and concentrate the solution, that's not really the case anymore. Now most of the water is in contact with a whole bunch of fatty acid carboxylic groups. Really, the waters and the carboxylic acid groups are hydrogen bonding, and you can form long-range, groups of hydrogen-bonded waters/carboxylic acids. When these things bond together, they stick together. You have to put in more heat to break that interaction, and that's why so much of the water stops boiling away out of the solution--because after a point, the interactions are so strong that you don't have enough heat to boil away the water. 

And that's why only a little bit of water boils off and your yolk doesn't explode! To test this theory, you could heat your fried egg above the boiling point of water, so that the temperature is high to break those linkages, and try to boil off all the water. However, the proteins and fatty acids in the egg will likely decompose before you hit that temperature, and then you'd be left with a black, tarry mess. 


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