- Author: Diane Nelson
I don’t know if plant scientists make better chefs, but knowledge of plant science can certainly improve our cooking. Take, for example, understanding how to handle oxidation, the interaction between oxygen molecules and all the many substances they may contact. Oxidation is what makes your fender rust and your copper penny turn green. As it relates to plants, oxidation is what causes fresh-cut produce to turn brown and wine to lose its flavor when left too long in an open bottle.
Perhaps you know how to thwart oxidation when preparing potatoes and serving sliced apples (and if not, we’ll get to that in a minute) but here is a less-common food that often falls victim to oxidation: pesto. Has this happened to you? You gather an armload of picture-perfect basil, blend it together with olive oil, pine nuts, garlic and cheese and produce a fantastic pesto sauce for your spaghetti. Fresh from the blender, it’s as green as your holiday tree. But by the time you serve it an hour later, it’s a dull shade of olive brown and has lost much of its taste. Oxidation strikes again.
Here’s a handy plant-science trick: Blanche your basil. Heat destroys the enzymes that cause oxidation and the resulting discoloration. Drop your fresh basil in a pot of boiling water for a few seconds and then shock it in a bowl of ice water. Dry it completely, proceed with your favorite recipe and your pesto will stay green and tasty for days. Here’s the recipe I like to use:
- 2 cups packed fresh basil leaves
- 2 cloves garlic
- 1/4 cup pine nuts (I use walnuts when I don’t have pine nuts)
- 2/3 cup extra-virgin olive oil, divided (for special treat, try using a UC Davis olive oil
- Salt and pepper, to taste
- 1/2 cup parmesan or other hard cheese
Combine the basil, garlic and nuts in a food processor or blender and pulse until coarsely chopped. Add 1/2 cup of the oil and process until fully incorporated and smooth. Season with salt and pepper.
If you’re eating it right away, add all the remaining oil and pulse until smooth. Transfer the pesto to a large serving bowl and mix in the cheese. Yum! If you’re freezing it (up to three months), transfer to an air-tight container and drizzle remaining oil over the top. Thaw and stir in cheese.