Just a quick hello and recipe.
I bought a few cool colored veggies a few days ago at the farmers market. Green zebra tomatoes. Purple beans.
Granted, the star here really was the corn. You might need to click on the link to see the beads of steam clinging to the kernels after a quick oven roast.
The purple beans were the coolest part. A quick online search for recipes ended in disappointment. These beauties turn a dull green with cooking. Boo! A bit more digging, mystery solved, and a potential solution discovered.
Are you ready for your science lesson? Don’t remember too much plant biology? Don’t worry, I’ll be gentle.
Purple beans, like other purple veggies contain anthocyanins, a water soluble vacuolar pigment. Vacuoles are organelles that “eat” proteins and are responsible for maintaining the acidic pH in plant cells. Anyway, anthocyanins in vacuoles give color to different berries and vegetables (beets, red cabbage, eggplant). Anthocyanins are very pH sensitive and require an acidic environment to maintain their purple color. Raise the pH (more basic), and they disappear along with their color. Heat breaks down anthocyanins directly and bursts the plant cells apart, diluting the acidity of the beans. The green, previously masked by the anthocyanin, emerges and takes over. Dull green beans.
I like a challenge. I read about cold shocking to keep the purple beans purple. About cooking in vinegar to raise the acidicty. About butter braising. Better yet, a butter bath. It’s unclear to me how the butter helps, but seriously, pamper the purple pods in a bubbling bath of butter? What could be bad about that?
I decided to start with a lemon juice dunk followed by the butter bath. I watched the beans carefully and the second they started to turn color, I poured them in a bowl and stuck them into the freezer. Ice water shock? I don’t think so. I wan’t about to throw out the beans babies let alone the bath butter!
As I finish typing up this recipe, the purple beans slowly turn green. A reminder that my little break is over and it’s time to turn back to work.
Remove silks from an ear of corn and rewrap it in its husk. Throw it right onto the rack of a hot oven and cook until the husks start to brown and and the scent of corn fills the air (less than 10 minutes). Meanwhile, rinse and trim a handful of purple beans and douse with a few tablespoons of lemon juice in a bowl. Let the beans sit for about 5 minutes. Heat a few pats of butter in a skillet until bubbling. Pour the beans and juice into the bubble, er, butter, bath. Quickly sauté beans, moving pan constantly over the heat. Did you know that the French verb, sauter, means to jump? Keep those babies jumping back and forth in the pan. At the first sign of green, pour the beans, juice, and butter back into the bowl and race it over to the freezer. Shave corn kernels off the cob, and toss them with two tomatoes, coarsely chopped. Pour the now chilled green beans mixture on top and be sure to scoop out all that butter and lemon juice as a vinaigrette. A few pinches of salt and toss. Eat quickly. Write a blog post.