Black Radish Nutrition facts

Black spanish radish or simply black radish is an edible bulbous taproot in the Brassicaceae family vegetables. It probably originated from the Eastern Mediterranean and Asia Minor regions, unlike other traditional Raphanus cultivars like daikon which took birth in Southern China.

Scientific name: Raphanus sativus var. niger

Black radish can be almost as pungent as horseradish, which is a close relative. It features rough, black skin and firm, white-fleshed inside which is spicy and not as juicy as red-globe or white-icicle daikon.

Black spanish radishes. Photo courtesy: Queena

Black radish is a cool-season annual taproot (hypocotyls), preferring sandy or loamy soil with good moisture to grow. It takes longer to harvest (60 days) than other traditional radish variants. It is quite a hardy plant, unlike daikon, because it stays tender and stands well even in harsh winters and does not bolt that quickly if exposed to excess summer heat.

Black Spanish radish can come in either round (3-5 cm in diameter) or cylindrical shapes (4-6 inches long), akin to in size and shape as red globe radish or slender Icicle radish respectively. However, it characteristically possesses black skin and a strong, peppery (piquant) flavor, unlike the mild and sweet flesh of the salad radishes. Its flesh is crispy and less juicy and keeps longer at room temperature than other radish varieties.

Their peppery flavor comes from the indoles and glucosinolates chemical compounds. Dehydroerucin, which is specific to radish (R. sativus), is the dominant aliphatic glucosinolate, accounting for over 80% of all glucosinolates.

Health benefits of Black Radish

The Use of black Spanish radish as a remedy to many illnesses has been in practice since ancient times. A popular Chinese proverb says "When winter radishes are in season, doctors should take a break".
Chinese believe that eating radish and other brassica group vegetables such as cabbage, cauliflower, and napa cabbage would bring wholesome health.
Black radish has the same calorie value as other conventional radishes. It holds just 16 calories per 100 grams. Nevertheless, it is the powerhouse of antioxidants, vitamins, and fiber.
Black radishes carry higher concentrations of glucosinolates compounds than its white variants. Glucoraphanin is the predominant glucosinolate found in almost all parts of the radish plant.
Glucoraphanin is converted into sulforaphane by hydrolysis enzymatic reaction which characteristically gives punchingly pungent flavor to it.
Research studies suggest that glucosinolates in the Brassica family vegetables offer anti-viral, immune-boosting, anti-cancer properties.
Fresh black radish roots are an average source of vitamin C (15 mg or 25% of DA per 100 g). Vitamin C is a powerful water-soluble antioxidant required by the body for the synthesis of collagen. It boosts immunity and helps in scavenging inflammatory free radicals.
In traditional medicines, the extraction of black radishes is used to treat liver and biliary disorders like indigestion, dyspepsia, gallbladder stones and to cure respiratory ailments, rheumatism, and arthritis.
Further, black radishes contain modest levels of the B-complex group of vitamins such as folates, vitamin B-6, riboflavin, thiamin, and minerals such as iron, magnesium, copper, and calcium.
Radish, being a member of cruciferous vegetables, carries other phytonutrients such as indole-3-carbinol (I3C) which are detoxifying agents. Experimental studies suggested that anti-estrogenic activities of I3C and DIM (di-indole methane) might help reduce the risk of hormone-dependent cancers such as breast and endometrium.

See the table below for in depth analysis of nutrients:

Black Radish (Raphanus sativus var. niger), Fresh, raw, Nutrition Value per 100 g, (Source: USDA National Nutrient data base)

Principle	Nutrient Value	Percent of RDA
Energy	16 Kcal	1%
Carbohydrates	3.40 g	3%
Protein	0.68 g	1%
Total Fat	0.10 g	<1%
Cholesterol	0 mg	0%
Dietary Fiber	1.6 g	4%
Vitamins
Folates	25 µg	6%
Niacin	0.254 mg	1.5%
Pyridoxine	0.071 mg	5.5%
Riboflavin	0.039 mg	3%
Vitamin A	7 IU	<1%
Vitamin C	14.8 mg	25%
Vitamin E	0 mg	9%
Vitamin K	1.3 µg	1%
Electrolytes
Sodium	39 mg	2.5%
Potassium	233 mg	5%
Minerals
Calcium	25 mg	2.5%
Copper	0.050 mg	5%
Iron	0.34 mg	4%
Magnesium	10 mg	2.5%
Manganese	0.069 mg	2.5%
Zinc	0.28 mg	2%
Phyto-nutrients
Carotene-ß	4 µg	--
Carotene-α	0 µg	--
Lutein-zeaxanthin	10 µg	--

Selection and storage

Spanish radishes can be available during the winter months in the US. Choose firm black tubers without any spots or blemishes. The tops, if still attached, should be bright green without any yellow, shriveled leaves.

Avoid oversized and tough, woody textured tubers. Also, avoid those with surface cracks or cuts.

At home, trim top greens as they rob nutrients off the tubers. Black Spanish radishes keep longer than other radishes. For extended storage, place them in the refrigerator. In the fridge, they stay well for several weeks if you keep them unwashed, without their top greens, and stored in a loose, perforated plastic bag.

Preparation and serving methods

Black radishes are rarely eaten as is because of their strong, biting flavor. Generally, they are used in vinaigrette salads or pickling.

To prepare, slice black radishes thinly or into sticks, sprinkle with salt, mix well, then cover the bowl and let rest for one hour, then rinse, drain, and use them in side dishes, salads, and as an accompaniment in seafood.

Here are some serving suggestions:

They can then be flavored with green onions and sour cream, used in salads, or served with remoulade sauce (mustard flavored sauce).
They can used with other vegetables like rutabaga in the preparation of steamed, stir-fried, or sauteed recipes.
Black radish coleslaw is a relishing side-dish, mixed with shredded cabbage, carrot, and mayonnaise.
They are also used in soups, stews, and omelets and with tofu.

Safety profile

Black radish contains goitrogenic glucosinolates such as glucobrassicin, sinalbin, etc. These substances reduce the production of thyroid hormones such as thyroxine. Other vegetables in the Brassica family vegetables carrying these substances also include cabbage, cauliflower, broccoli, brussel sprouts, etc.

Goitrogens may cause swelling of the thyroid gland and should be avoided in individuals with thyroid dysfunction. However, they may be used in normal diets in healthy persons. (Medical disclaimer).