Asparagus is a young tender shoot (spear) vegetable, emerging out from its underground root system. The flavorful spears are a favorite spring season delicacies. Their use as food was well recognized by the ancient Greeks and Romans as a prized delicacy. One of the oldest recorded vegetables, it thought to have originated along the coastal regions of eastern Mediterranean and Asia Minor regions.
Botanically, it is a herbaceous perennial plant belonging to the Asparagaceae family. It is closely related to the Liliaceae plants which also include onion, garlic, tulip, daffodil…etc. Scientific name: A. officinalis. This spear vegetable is grown extensively nowadays as a major commercial crop in China, Europe, Peru, Australia, and the USA.
Asparagus crowns planted in early spring. It grows into tall, branched stems, bearing fine fern-like green needles (phylloclades); giving the whole plant an overall feathery appearance. The fresh crop can also be established by direct seeding or through transplanting 10-12 week-old seedlings. A fully-grown plant reaches about 5 feet in height. Young scaly edible spears emerge from the underground extensive matted root systems, which can be ready for harvesting by early spring.
In general, 7 to 9 inches tall young shoots are harvested by either snapping or using a paring knife, cutting close to the ground level. There is no need to cut asparagus shoots far below the soil with a knife, which might injure other erupting buds on the crown. The stump that left in the ground after snapping dries up and disintegrates.
Warm weather would adversely result in premature opening up of spear tip that might reduce their overall flavor and quality. Asparagus is harvested once a year for over 8 to 10 week period in a season.
White or blanched asparagus (spargel) spears reaped by heaping up surrounding soil around the erupting shoots, depriving them of sunlight. This method, like in endive, makes the shoots turn pale through inhibition of photosynthesis. Often, these blanched spears preferred over dark ones in the Europe due to their pleasant taste and delicate flavor.
Health Benefits of Asparagus
Asparagus is a very low-calorie vegetable. 100 g fresh spears carry just 20 calories.
Besides, its spears contain moderate levels of dietary fiber. 100 g of fresh spears provide 2.1 g of roughage. Dietary fiber helps control constipation conditions, decrease bad (LDL) cholesterol levels by binding to it in the intestines and regulate blood sugar levels. Studies suggest that high-fiber diet help cut down 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 and irritable bowel syndrome.
Fresh asparagus spears are a good source of anti-oxidants such as lutein, zeaxanthin, carotenes, and cryptoxanthins. Together, these flavonoid compounds help remove harmful oxidant free radicals from the body protect it from possible cancer, neurodegenerative diseases, and viral infections. Their total antioxidant strength, measured regarding oxygen radical absorbance capacity (ORAC value), is 2150 µmol TE/100 g.
Fresh asparagus is rich sources of folates. 100 g of spears provide about 54 µg or 14% of RDA of folic acid. Folates are one of the essential co-factors for the DNA synthesis inside the cell. Scientific studies have shown that adequate consumption of folates in the diet during pre-conception period and early pregnancy helps prevent neural tube defects in the newborn baby.
Its shoots are also rich in the B-complex group of vitamins such as thiamin, riboflavin, niacin, vitamin B-6 (pyridoxine), and pantothenic acid. These group of vitamins is essential for optimum cellular enzymatic and metabolic functions.
Fresh asparagus also contains fair amounts of antioxidant vitamins such as vitamin-C, vitamin-A, and vitamin-E. Regular consumption of foods rich in these vitamins helps the body develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals from the body.
Its shoots are also an excellent source of vitamin-K. 100 grams carry about 35% of DRI. Vitamin-K has potential role bone health by promoting bone formation activity. Adequate vitamin-K levels in the diet help limiting neuronal damage in the brain; thus, has established a role in the treatment of patients with Alzheimer’s disease.
Asparagus is an excellent source of minerals, especially copper and iron. Also, 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 used by the body as a co-factor for the antioxidant enzyme, superoxide dismutase. Copper required in the production of red blood cells. Iron is essential for cellular respiration and red blood cell formation.
Selection and storage
Although one may find asparagus all around the season in the supermarkets, its spears are at their best and most flavorful during the spring. In Europe, its shoots sold in the shops from December till June.
Asparagus should be used as soon as possible after harvesting. Otherwise, it soon loses sweetness since most of its sugar converted into starch. Purchasing from the local farms or farmer markets would be an ideal way to enjoy them fresh.
In the markets select tender, firm, straight, smooth, uniform sized, dark green/purple stalks with tightly closed tips. Avoid thick stalks with broad ridges in the stems, sunken or dull colored, as they indicate old stock and hence, off-flavored.
Since its spears perish early, they should be harvested in the morning hours when the weather is cold. After picking, immerse them in ice-cold water to remove heat, drain the water and place spears inside plastic bags. Store in the refrigerator set at 38 to 40 degrees F and 90% to 95% relative humidity. At higher temperatures, its spears tend to lose natural sugars and vitamin-C. As a result, they lose their flavor as they become tougher and begin to decay.
Preparation and serving methods
Asparagus shoots are one of the most sought-after vegetables during the spring season.
Fresh spears preferred in cooking. To prepare, wash them in cool running water with a gentle scrub. Pencil thin, tender spears can be cooked directly. Thick stalks, however, may need peeling before being used in the recipes.
In general, its spears just need brief cooking. In some households, traditional pots are employed to cook asparagus wherein its stalks immersed in boiling water while tips just allowed to steam cook.
Here are some serving suggestions:
Asparagus spears can be enjoyed raw, steamed, sautéed, stir-fried or mixed with vegetables, beans, poultry or seafood.
Steamed spears served with citrus hollandaise sauce, melted butter, parmesan or pecorino cheese in beautiful French style recipes.
Grilled spring onions and asparagus stalks smeared with macadamia nut oil is a mouth-watering appetizer.
Stir-fry its tender shoots with sesame seeds, and season with garlic, ginger, and pepper paste.
Many restaurants in Germany offer special spargel menus during the spring season.
In general, asparagus is well tolerated, and allergic reactions are relatively rare.
Ingestion of young shoots may give an offensive smell to urine. It 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.