HOW COOKING CHANGES THE TEXTURE AND FLAVOR OF FOODS

As you can see, these twelve cooking methods present all sorts of options for preparing raw ingredients. But how do you know which method to use when? To answer this question, let’s begin by looking at how each method affects the texture and flavor of food. To illustrate this point when I teach, I serve the class a rather cavalier offering: an all-zucchini tasting menu. Intended more as a teaching device than a zucchini degustation, this menu allows us to observe how seven different cooking techniques bring out a variety of sensations in something as pedestrian as zucchini. As you read along, try to imagine the textures and flavors as I describe them. Or better still, buy some medium-sized zucchini, go into the kitchen, and cook up a comparative tasting of your own.

First, it’s important to taste some zucchini raw. Slice a zucchini into a few ½-inch-thick coins and bite into a slice. You’ll discern all sorts of vital information about its age, freshness, and flavor. In zucchini, ripeness registers on the palate as sweetness. And freshness manifests as firmness. Fresh zucchini resist light pressure if you squeeze them a bit. An underripe zucchini could be described as “vegetal” or overly “herbaceous.” An overripe zucchini can be tough and bitter, thanks to its seeds. Given this bitter flavor, fine cooks prefer younger, more tender zucchini, also called fancy zucchini.

Next, taste the zucchini slices prepared by three different moist-heat cooking methods. When steamed, the texture of zucchini feels different on the tongue. It’s less spongy than the raw zucchini and considerably more damp. There’s more contrast in texture between its skin and flesh, too. The skins of steamed zucchini are a bit tougher than the center pulp. Flavorwise, steaming brings out a zucchini’s sweetness.

When you bite into boiled zucchini, the skin softens and yields easily to the flesh. Also, the boiled slices, which soften evenly as they cook, pick up the pleasant flavor of the salt that was added to the cooking water. Nutritionwise, boiling vegetables has fallen out of favor because nutrients are leached out into the cooking water. If you opt to boil mild-flavored vegetables such as zucchini, save the cooking water to use in place of stock when making soups.

It’s unnecessary to taste zucchini that are poached or blanched; poached are similar to boiled and blanched resemble lightly steamed zucchini.

Next, taste zucchini slices cooked by dry-heat cooking methods. We can assume that broiled zucchini are similar to grilled, stir-fried are like sautéed, and baked are comparable to roasted.

Roasting is the cooking method of choice for preparing stuffed zucchini. The dry heat of the oven dries out the skin, creating a nice, firm shell for a savory meat or rice filling. The tougher skin supports the weight of the stuffing, and the layer of spongy flesh just inside the skin absorbs the juices and flavors of the stuffing as it softens during roasting. To protect the skin from becoming leathery, brush some olive oil on the outside before roasting or baking. Flavorwise, the natural sugars in the zucchini caramelize a bit in the intense heat of the oven, which is why roasted zucchini tastes richer than the steamed or boiled version. Zucchini cut up before roasting develop a rich flavor, thanks to both the olive oil they are tossed with before they go into the oven and the caramelization that occurs during roasting. The roasted slices also have a creamy, softer texture than the roasted halves for stuffing.

Of all the various cooking methods included in this little research project, sautéed zucchini are consistently the students’ least favorite. Their flavor is rather bland, and the texture can be described as flabby or crisp-tender, depending on how long the vegetable is cooked.

Often, before deep-frying, vegetables are coated in a batter that cooks into a crispy coating and locks in the food’s natural moisture. For this experiment, in order to focus on the flavor of the cooked squash, I suggest that you deep-fry both some plain zucchini slices and some dredged in seasoned flour. You’ll discover that neither treatment enhances the texture nor brings out the naturally sweet, fresh flavor of the deep-fried vegetable. Simply put, deep-frying actually masks the true flavor of zucchini.

The last dry-heat cooking technique in this experiment is grilling. For this test, slice raw zucchini lengthwise into ¼-inch-thick slices and brush all surfaces with olive oil. Grilling gives zucchini a rich, complex taste. The characteristic seared or charred exterior imparts a distinctive flavor that is associated with a sense of satiety, or fullness. Indeed, don’t be surprised if grilled zucchini seem more filling than steamed zucchini. Zucchini grilled with perfectly seared outsides and a soft, creamy flesh are succulent and tender, with the caramelized grill marks enhancing the vegetable’s natural sweetness.

If I had to choose my favorite method for cooking zucchini, without a doubt, it would be braising. In class, I save this moist-heat technique for last for two reasons: It delivers the most complex flavor, and I don’t want to confuse the palate because, by definition, all the other samples are relatively plain. Similarly, by definition, braised food is cooked in a flavorful liquid that contributes to its taste. In fact, I think zucchini were put on the earth to sponge up other flavors. As noted earlier, raw zucchini have both a bland flavor and spongy texture; both attributes make the squash a logical candidate for braising—or stewing—in a flavorful liquid. Braised Summer Squash with Sweet Peppers, Tomatoes, and Basil  is a good example.

First, sauté some onions and bell peppers with some sliced zucchini in a little olive oil. Add a little salt to draw out some of the moisture and concentrate the flavors. When the vegetables are glistening all over and starting to brown on both sides, add some chopped tomatoes, enough to almost cover the zucchini. Next, bring all to a rolling boil, then reduce the heat so the mixture simmers steadily. Partially cover the pan and simmer the zucchini until the edges flop when you pick up a slice with a fork. At this point, the zucchini will have absorbed some flavor from the tomatoes. A final seasoning with salt is all that’s needed.

Braising breaks down the fibers of the zucchini, resulting in tender slices that readily absorb the flavors of not only the tomatoes, onions, and peppers, but also the olive oil and salt. Simply put, the overall flavor of the braised zucchini is greater than the sum of its parts.

This zucchini exercise gives you an indication of how both the flavor and texture of a simple vegetable are transformed by each of the twelve dry- and moist-heat cooking methods.

By Linda Carucci in "Cooking School Secrets for Real World Cooks", second edition, Author House, USA, 2016, excerpts pp. 42-44. Digitalized, adapted and illustrated to be posted by Leopoldo Costa.