Savor: Radishes

Photo: Sara Remington

Scientifically known as Raphanus sativus, “radish” is derived from radix, the Latin word for “root.” Anchored just below the soil’s surface, radish is an edible root. These buried jewels are among the oldest known cultivated vegetables, possibly originating in prehistoric times in Europe or western Asia. The radish proliferated throughout the Mediterranean region in the 16th century, arriving in the American northeast in the early 1600s.

Radishes vary in shape and size and are available in dozens of colorful varieties, each worthy of consideration.

In the Kitchen

Radishes range from about a half-inch in diameter for the smallest red globe to about 18 inches long and 3 inches wide for the large daikon. Despite these differences, younger and smaller size typically equates to more sweetness and tender flesh; older and larger size can indicate the interior flesh is dried out or woody. (One half-pound is about 10 to 14 radishes and should yield approximately 1⅔ cups sliced.)

Beyond a good wash, most radishes are ready to eat, no peeling required. Pair radishes with citrus fruits, especially orange and lemon; fresh herbs such as chives and parsley; umami-rich miso paste and vinegars; as well as simple salt, butter (especially browned), yogurt or cream.

The red globe and their shapelier French breakfast radish cousins add pops of color to salads, sandwiches and crudité platters. The pale green-skinned, fuchsia-fleshed watermelon radish, an heirloom Chinese daikon, generally is kept raw as cooking dulls its color and already mild flavor. The color and flavor of dark-skinned Spanish black radishes are not affected by cooking and can be enjoyed both raw and cooked with or without skin. White icicle and daikon radishes are milder and often are featured in Asian and Latin cuisines raw as a garnish or pickled.

Cooking radishes increases their versatility, enhances their innate sweetness and tames their spicy flavor. In addition, cooking modifies the texture, from a crisp bite to softness similar to cooked turnip or carrot. Sauté or roast small red radishes whole (or cut into wedges if they are large) and toss with pasta, rice or whole grains, or use in stir-fries, grilled mixed vegetables, egg scrambles or braises.

With a peppery-hot taste similar to mustard greens or watercress, leafy green radish tops are safe to eat. Sautéing or steaming often are the preferred methods of preparation. Greens from radishes harvested earlier in the growing season are milder and tenderer, and often are preferred raw in salads, pesto or as a garnish.

In the Clinic

On average, a 1-cup serving of raw radishes has about 4 grams of carbohydrate and nearly 1 gram of protein in fewer than 20 calories. This serving is an excellent source of vitamin C. A cup of raw radishes also delivers 8 percent of the Daily Value of potassium and 7 percent of the Daily Value of folate. Additionally, radishes are considered low-FODMAP and are among the most hydrating vegetables with a water content of more than 95 percent.

Brightly colored varietals — including the common red globe, bi-colored French breakfast, watermelon and purple daikon, as well as Spanish black radishes — contain pigments with antioxidant properties. Rich hues indicate the presence of anthocyanins, which research suggests may help decrease inflammation and cancerous tumor growth, possibly offering protection from heart diseases and certain cancers.

Like other cruciferous vegetables in the Brassica family, radishes are rich in a unique group of phytochemicals called glucosinolates. When radishes and other raw cruciferous vegetables are broken down by chopping or chewing, sulfurous isothiocyanate compounds with potential anti-carcinogenic properties are produced. These isothiocyanates are responsible for some of the spiciness in radishes — the greater the isothiocyanate concentration, the hotter the taste.

In Quantity

Red radishes are available in grocery store produce departments year-round, but buying in-season (usually April through June) ensures the best flavor and quality. French breakfast, watermelon, purple daikon, icicle and Spanish black radishes often are available at specialty grocers or farmers markets, and daikon radishes are common at Asian markets. Look for radishes that are firm, uncracked and vibrantly colored; avoid those that look faded, wrinkled or cracked, or feel soft. If the leaves are attached, they should be bright green and unblemished — never wilted.

Radishes keep well for about a week in the refrigerator crisper drawer, loosely wrapped in plastic. To retain freshness, wash radishes just prior to use and, if purchased as a bunch, trim the greens to within an inch of the stem before refrigerating. To reinvigorate soft radishes and add back some of their natural crispness, soak in ice water 30 to 60 minutes before using.

A foodservice staple — commonly used in salads and as garnishes or crudités — radishes are almost exclusively sold fresh, since freezing compromises flavor and texture. In the U.S., raw radishes are available in larger quantities as bunches with greens or whole and trimmed in 5- to 40-pound cases. Depending on market variability, additional options may include raw straight or crinkle-cut coins or matchsticks.

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Heather Goesch
Heather A. Goesch, MPH, RDN, LDN, is a registered dietitian nutritionist, freelance writer and recipe developer currently living in the south of France. Read her blog for healthy, seasonal recipe inspiration, and connect with her on Facebook, Instagram, LinkedIn, Pinterest or Twitter.