Asparagus nutrition facts
Asparagus has been revered by ancient Greek and Romans as a prized delicacy. One of the oldest recorded vegetable; it is thought to have originated along the coastal regions of eastern Mediterranean and Asia Minor areas. Botanically this herbaceous perennial plant belongs to the liliaceae family, of the genus, A. officinalis; a very large genus which also includes onion, garlic, tulip, daffodil …etc.
To cultivate, asparagus crowns are planted by early spring grows into tall branched stems bearing fine fern-like green needles (phylloclades) giving the plant an overall feathery appearance. The plant can also be established by transplanting of 10-12 week old seedlings or direct seeding. A fully-grown plant reaches about 5 feet in height. Young scaly edible spears emerge from the extensive matted root systems, which are ready for harvesting by early spring.
In general, 7 to 9 inch long young shoots harvested by either snapping or using a paring knife at the ground level. There is no need to cut asparagus shoots far below the soil with a knife. This may injure other erupting buds on the crown. The stump that is left in the soil after snapping dries up and disintegrates. Warm weather makes spears tips to open prematurely which reduces their flavor and quality. Asparagus is normally harvested once a year over an 8 to 10 week period.
White or blanched asparagus (spargel) spears are produced by covering erupting shoots with mound, depriving them of sunlight. This method, like in endive, makes the shoots turn white due to lack of photosynthesis. Blanched stems are preferred in Europe due to their delicate taste and pleasant flavor.
Health benefits of Asparagus
- Asparagus is a very low calorie vegetable. 100 g fresh spears give only 20 calories. More calories will be burnt to digest than gained, the fact, which fits in to the category of low calorie or negative calorie vegetables.
- In addition, the shoots have good levels of dietary fiber. Dietary fiber helps control constipation conditions, decrease bad, "LDL" cholesterol levels by binding to it in the intestines, and regulates blood sugar levels. In addition, high fiber diet helps prevent colon-rectal cancer risks by preventing toxic compounds in the food from absorption.
- Its shoots have long been used in many traditional medicines to treat conditions like dropsy andirritable bowel syndrome.
- Fresh asparagus spears are good source of anti-oxidants such as lutein, zeaxanthin, carotenes, andcrypto-xanthins. Together, these flavonoid compounds help remove harmful oxidant free radicals from the body protect it from possible cancer, neuro-degenerative diseases, and viral infections.
- Fresh asparagus are rich in folates. 100 g of spears provide about 54 mcg or 14% of RDA of folic acid. Folates are one of the important co-factors for DNA synthesis inside the cell. Scientific studies have shown that adequate consumption of folates in the diet during pre-conception period and during early pregnancy help prevent neural tube defects in the newborn baby.
- The shoots are also rich in B-complex group of vitamins such as thiamin, riboflavin, niacin, vitamin B-6 (pyridoxine), and pantothenic acid those are essential for optimum cellular enzymatic and metabolic functions.
- Fresh asparagus also contains fair amounts of anti-oxidant vitamins such as vitamin-C, vitamin-A and vitamin-E. Regular consumption of foods rich in these vitamins helps body develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals from the body.
- Its shoots are also good source of vitamin K; provides about 35% of DRI. Vitamin K has potential role bone health by promoting osteotrophic (bone formation) activity. Adequate vitamin-K levels in the diet helps limiting neuronal damage in the brain; thus, has established role in the treatment of patients suffering from Alzheimer's disease.
- Asparagus is good in minerals especially copper and iron. In addition, it has small amounts of some other essential minerals and electrolytes such as calcium, potassium, manganese, and phosphorus.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. Copper is required in the production of red blood cells. Ironis required for cellular respiration and red blood cell formation.
| Principle | Nutrient Value | Percentage of RDA |
|---|---|---|
| Energy | 20 Kcal | 1% |
| Carbohydrates | 3.38 g | 2.5% |
| Protein | 2.20 g | 4% |
| Total Fat | 0.12 g | 0.5% |
| Cholesterol | 0 mg | 0% |
| Dietary Fiber | 2.1 g | 5.5% |
| Vitamins | ||
| Folates | 52 µg | 13% |
| Niacin | 0.978 mg | 6% |
| Pantothenic acid | 0.274 mg | 5% |
| Pyridoxine | 0.091 mg | 7% |
| Riboflavin | 0.141 mg | 11% |
| Thiamin | 0.143 mg | 12% |
| Vitamin C | 5.6 mg | 9% |
| Vitamin A | 756 IU | 25% |
| Vitamin E | 1.13 mg | 7.5% |
| Vitamin K | 41.6 µg | 35% |
| Electrolytes | ||
| Sodium | 2 mg | <1% |
| Potassium | 202 mg | 4% |
| Minerals | ||
| Calcium | 24 mg | 2.5% |
| Copper | 0.189 mg | 21% |
| Iron | 1.14 mg | 14% |
| Magnesium | 14 mg | 1% |
| Manganese | 0.158 mg | 7% |
| Phosphorus | 52 mg | 7.5% |
| Selenium | 2.3 mcg | 4% |
| Zinc | 0.54 mg | 5% |
| Phyto-nutrients | ||
| Carotene-ß | 449 µg | |
| Carotene-α | 9 µg | |
| Lutein-zeaxanthin | 710 µg |
Selection and storage
Although one may find asparagus all around the season in the supermarkets, it is best available and is most flavorful in the springs. In Europe, its spears are best available from December until June.
Asparagus should be used as soon as possible after harvesting. Otherwise, it loses flavor as most its sugar will be converted to starch. So pick them from the local farms whenever possible. Select fresh, tender, firm, straight, smooth, uniform sized, dark green/purple stalks with tightly-closed tips. Avoid thick stalks with wide ridges in the stems, sunken or dull color ones, as they are old stalk and off flavored.
As its spears perish early, they should be harvested in the morning hours when air temperatures are cool. After picking, immerse them in ice-cold water to remove the heat; then drain the water and place the spears in plastic bags and store in the refrigerator at 38 to 40 degrees F with 90 to 95% relative humidity. At higher temperature, its spears lose natural sugar, vitamin-C, and flavor and they become tough and start to decay.
Preparation and serving methods
Fresh spears preferred for cooking. To prepare asparagus, wash the vegetable in cool water, gently scrubbing the sand from the stalks with your fingers. Thin tender spears can be cooked directly. Thick stalks may need peeling before used in the recipes.
In general, the spears needs to be cooked briefly. In some households, traditional pots are used to cook asparagus where in its stalks immersed in boiling water while tips just allowed cooking by steam only.Asparagus shoots are one of the most sought after vegetables in the spring season.
Here are some serving tips:
- Asparagus spears can be enjoyed raw, steamed, sautéed, stir-fried or mixed with vegetables, beans, poultry or seafood.
- Steamed spears are served with citrus hollandaise sauce, melted butter, parmesan or pecorino cheese in beautiful French style recipe.
- Grilled spring onions and asparagus stalks smeared with macadamia nutoil is a mouth-watering appetizer.
- Its stalks stir-fried with added sesame seeds in garlic, ginger, and pepperpaste.
- Many restaurants in Germany offer special spargel menus during spring season.
Safety profile
In general asparagus is well tolerated in general population and allergic reactions are quite rare to occur.
Ingestion of young shoots may give offensive smell to urine. This is due to the metabolism of asparagusic acid, which breaks down into various sulfur-containing degradation products such as methanethiol, sulfides...etc. The condition, however, is harmless.