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Kohlrabi or knol-khol or German Turnip is a stout, round "tuber" like vegetable of the brassica family; same as that of cabbage, broccoli, cauliflower, kale, collard greens, and brussels sprouts belongs to. This stem vegetable is native to Europe. Scientific name: Brassica oleracea (Gongylodes Group).

Knol knol is a perennial, cool season vegetable, grown all over the temperate climates for its succulent round shaped modified stem as well its turnip-flavored greens.

The plant requires well-drained fertile soil and average sun shine to flourish. The edible stem attains maturity and ready for harvest in 55-60 days after sowing. Approximate weight is 150 g. The tuber is tolerant to cracking and has good standing ability for up to 30 days after maturity.

Knol-knols have similar taste and texture as that of a broccoli stem or cabbage, but milder and sweeter. The younger stems have crispy, pleasant taste and rich flavor.

Two main varieties knol-knol exists; white and purple. However, internally, both the "white" (actually light green color) as well as purple types has similar cream yellow color edible flesh. Some of the popular cultivars of kohlrabi grown worldwide are white Vienna, white Danube, purple vienna, and grand duke.

Health benefits of Kohlrabi (Knol-khol)

  • Mildly sweet, succulent Kohlrabi is notably rich in vitamins and Dietary fiber; but has only 27 calories per 100 g, negligible amount of fat, and zero cholesterol.

  • Fresh kohlrabi stem is rich source of vitamin-C; provides 62 g per 100g weight that is about 102% of RDA. Vitamin C (ascorbic acid) is a water-soluble vitamin and powerful anti-oxidant. It helps body maintain healthy connective tissue, teeth, and gum. Its anti-oxidant property helps body protect from 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 appears to protect against prostate and colon cancers.

  • This stem vegetable is especially contain good amounts of many B-complex group of vitamins such as niacin, vitamin B-6 (pyridoxine), thiamin, pantothenic acid etc that acts as co-factors to enzymes during various metabolism inside the body.

  • Knol-knol notably has good levels of minerals; copper, calcium, potassium, manganese, iron, and phosphorus are especially available in the stem. Potassium is an important component of cell and body fluids that helps controlling heart rate and blood pressure by countering effects of sodium. Manganese is used by the body as a co-factor for the antioxidant enzyme, superoxide dismutase.

  • In addition, its creamy color flesh contains small amounts of vitamin A and carotenes.

  • Kohlrabi leaves or tops, like turnip greens, are also very nutritious greens abundant in carotenes, vitamin A, vitamin K, minerals, and B-complex group of vitamins.
Principle Nutrient Value Percentage of RDA
Energy 27 Kcal 1.5%
Carbohydrates 6.20 g 5%
Protein 1.70 g 3%
Total Fat 0.10 g <1%
Cholesterol 0 mg 0%
Dietary Fiber 3.6 g 10%
Vitamins

Folates 16 µg 4%
Niacin 0.400 mg 2.5%
Pantothenic acid 0.165 mg 3%
Pyridoxine 0.150 mg 11.5%
Riboflavin 0.020 mg 1.5%
Thiamin 0.050 mg 4%
Vitamin A 36 IU 1%
Vitamin C 62 mg 102%
Vitamin K 0.1 mcg <1%
Electrolytes

Sodium 20 mg 1%
Potassium 350 mg 7%
Minerals

Calcium 24 mg 2.5%
Copper 0.129 mg 14%
Iron 0.40 mg 5%
Magnesium 19 mg 5%
Manganese 0.139 mg 6%
Phosphorus 46 mg 6.5%
Selenium 0.7 µg 1%
Zinc 0.03 mg <1%
Phyto-nutrients

Carotene-ß 22 µg --
Crypto-xanthin-ß 0 µg --
Lutein-zeaxanthin 0 µg --

Selection and storage

This attractive stem vegetable is available at its best during winter months from November until March. Over-maturity as well as exposure of crop to excessive sunlight makes the stem woody and tough in texture resulting in its poor eating quality. Fresh kohlrabies should have crunchy texture and impart rich flavor.

In the stores, buy medium-sized, fresh tubers and 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 is indication of over-maturity and out of flavor.

Knol-knols have good keeping qualities; can be placed at room temperature for 2-3 days. However, If you wish to store for few more days, then keep them in the refrigerator set at temperature below 35 degree F and high humidity level to maintain vitality.

Preparation and serving methods

Kohlrabi stems should be washed thoroughly in clean running water and swished in saline water for about 10-15 minutes in order 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 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.