Kohlrabi, also known as knol-khol or German Turnip, is a stout, round, tuberous vegetable in the Brassica family, the large family which also includes cabbage, broccoli, cauliflower, kale, collard greens, and brussels sprouts. This stem vegetable is native to Europe. Scientific name: Brassica oleracea (Gongylodes Group).
Kholrabi is a perennial, cool season vegetable. It is grown all over the temperate climates for its succulent round shaped modified stem as well for its turnip-flavored top greens.
The plant requires well-drained fertile soil and average sunlight to flourish. Its edible stem attains maturity and ready for harvest in 55-60 days after sowing. Approximate weight is 150 g. Unlike turnip, which is a root-vegetable, kohlrabi, being a stem vegetable, is less prone to cracking and has a good standing ability for up to 30 days even after maturity.
Kohlrabis have similar taste and texture like that of a broccoli stem or cabbage, but milder and sweeter. Young, tender ones are crispier in texture, have a pleasant taste, and rich in flavor.
Two main varieties of knol-khol exist, white and purple. However, internally, both the “white” (actually light green color) as well as purple types have similar cream-yellow color edible flesh. Some of the popular cultivars grown worldwide are white Vienna, white Danube, purple vienna, and grand duke.
Health benefits of Kohlrabi (Knol-khol)
Mildly sweet, crispy textured kohlrabi is notably rich in vitamins and dietary fiber; however, it has only 27 calories per 100 g, a negligible amount of fat, and zero cholesterol.
Fresh kohlrabi stem is a rich source of vitamin-C; provides 62 mg per 100 g weight that is about 102% of RDA. Vitamin-C (ascorbic acid) is a water-soluble vitamin, and powerful antioxidant. It helps the human body maintain healthy connective tissue, teeth, and gum. Its antioxidant property helps the human body combat diseases and cancers by scavenging harmful free radicals from the body.
Kohlrabi, like other members of the Brassica family, contains health-promoting phytochemicals such as isothiocyanates, sulforaphane, and indole-3-carbinol that are supposed to protect against prostate and colon cancers.
It especially contains good amounts of many B-complex groups of vitamins such as niacin, vitamin B-6 (pyridoxine), thiamin, pantothenic acid, etc., that acts as co-factors to enzymes during various metabolism functions inside the body.
Knol-knol notably has good levels of minerals; copper, calcium, potassium, manganese, iron, and phosphorus are especially concentrated in it. Potassium is an important component of cell and body fluids that helps controlling heart rate and blood pressure by countering effects of sodium. The human body uses manganese as a co-factor for the antioxidant enzyme, superoxide dismutase.
Further, its creamy color flesh contains small amounts of vitamin-A and carotene pigments.
Kohlrabi leaves or tops, like turnip greens, are also very nutritious greens abundant in carotenes, vitamin-A, vitamin-K, minerals, and the B-complex group of vitamins.
Selection and storage
This visibly attractive stem vegetable is available, at its best, during the winter months from November until March. Overmaturity, as well as exposure of crop to excessive sunlight, makes its stem woody and tough resulting in its poor eating quality. Fresh kohlrabies should have a crunchy texture and impart rich flavor.
In the stores, buy medium-sized, fresh tubers that feel heavy in hand for their size. Avoid those with cracks, cuts, spoiled or mold infested. Do not buy if they have lighter weight for their size and excessively woody in consistency as it indicates signs of overmaturity and therefore, unappetizing.
Knol-kohl exhibits good keeping qualities and can be placed at room temperature for 3-5 days. However, If you wish to store for few more days, then keep them in the refrigerator set at temperature below 35 degrees F and high humidity level to maintain vitality.
Preparation and serving methods
Kohlrabi stems should be washed thoroughly in clean running water and swish in saline water for about 10-15 minutes to remove any surface soil, dirt, and any insecticide/fungicide residues.
Just before cooking, remove any leaves and trim the stem ends. Peel the skin using a paring knife.
Here are some serving tips:
Fresh young crispy knol-knol can be used raw in salad/coleslaw.
It mixes well with other vegetables and greens in a variety of kohlrabi recipes like squash empanadas.
Peeled stem, cut into slices or cubes, can be mixed with other vegetables like potatoes and stewed with onion, garlic, and tomato.
Stewed knol-knol cubes mix well with meats and poultry.
Kohlrabi may contain goitrogens, plant-based compounds found in the cruciferous vegetable like cauliflower, broccoli, etc., may cause swelling of the thyroid gland and should be avoided in individuals with thyroid dysfunction. However, knol-knols may be eaten freely in the healthy person.