Spinach

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{{Taxobox | color = lightgreen | name = Spinach | image = Spinacia oleracea Spinazie bloeiend.jpg | image_width = 240px | image_caption = Spinach in flower | regnum = Plantae | divisio = Magnoliophyta | classis = Magnoliopsida | ordo = Caryophyllales | familia = Amaranthaceae | genus = Spinacia | species = S. oleracea | binomial = Spinacia oleracea | binomial_authority = L. }}

Spinach (Spinacia oleracea) is a flowering plant in the family Amaranthaceae, native to central and southwestern Asia. It is an annual plant (rarely biennial), which grows to a height of up to one metre. The leaves are alternate, simple, ovate to triangular-based, very variable in size from about 3-30 cm long and 1-15 cm broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem. The flowers are inconspicuous, yellow-green, 3-4 mm diameter, maturing into a small hard dry lumpy fruit cluster 5-10 mm across containing several seeds.

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Cultivation and uses

Image:Spinach produce-1.jpg Spinach is an important leaf vegetable, now grown throughout the temperate regions of the world. It is most productive in cool seasons and climates, since heat will cause the spinach to go to seed too early. When cooked its volume is decreased by three quarters.

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History

Spinach was first cultivated in southwestern Asia, perhaps in Persia. The word itself is derived from the Persian word اسفناج Esfenaj. The Chinese referred to it in 647 as 'the herb of Persia'.

It arrived in North Africa through Syria and Arabia. In 1100, the Moors introduced it to Spain. Over the next century, prickly seeded spinach spread throughout Europe, being grown primarily in monastery gardens. A cookbook dating from 1390, belonging to King Richard II, contains spinach recipes. Smooth seeded spinach seems to have spread through Europe slightly later. Its use in England was first documented in 1551.

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Nutrition

In popular folklore, spinach is a rich source of iron. In reality, a 60 gram serving of boiled spinach contains around 1.9 mg of iron. A good many green vegetables contain less than 1 mg of iron for an equivalent serving. Hence spinach does contain a relatively high level of iron for a vegetable.

However, in terms of its nutritional value (the amount of iron actually absorbed by the body) the benefits of spinach have been greatly overstated. In the first instance, this is because the body cannot absorb the non-haem iron from vegetables as efficiently as the haem-iron found in meats, particularly lean meats. The body's absorption of non-haem iron can nevertheless be improved by consuming foods that are rich in vitamin C. However, more importantly, spinach contains high levels of oxalate. The oxalate in spinach binds to iron to form ferrous oxalate, meaning it cannot be broken down and absorbed by the body. As a consquence, the amount of iron that can be absorbed from spinach is negligible.

The myth about spinach and its high iron content may have first been propagated by Dr. E. von Wolf in 1870, because a misplaced decimal point in his publication led to an iron-content figure that was ten times too high. In 1937, German chemists reinvestigated this "miracle vegetable" and corrected the mistake. It was described by T.J. Hamblin in British Medical Journal, December 1981.

Spinach also has a high calcium content. Once again, this is of negligible nutritional benefit because the oxalate in spinach also binds with calcium. By way of comparison, the body can absorb about half of the calcium present in broccoli, yet only around 5% of the calcium in spinach. Another negative for spinach is that oxalate can contribute to gout and kidney stones.

Despite these nutritional myths, Spinach still has a great deal of nutritional value, especially when fresh, steamed, or quickly boiled. It is a rich source of Vitamin A, Vitamin C, Vitamin E and several vital antioxidants. Recently, opioid peptides called rubiscolins have also been found in spinach. It is a source of folic acid, and this vitamin was first purified from spinach. To benefit from the folate in spinach, it is better to steam it than to boil it. Boiling spinach for four minutes can halve the level of folate. The nutritional benefits of spinach were discussed in detail in the Skeptic magazine, (Winter 2005).

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Types of Spinach

A distinction can be made between older varieties of spinach and more modern varieties. Older varieties tend to run up to seed too quickly in warm conditions. Newer varieties tend to grow more rapidly but have less of an inclination to run up to seed. The older varieties have narrower leaves and tend to have a stonger (although more bitter) taste. Most newer varieties have broader leaves and round seeds.

There are 3 basic types of Spinach:

  • Savoy has dark green, crinkly and curly leaves. It is the type sold in fresh bunches in most supermarkets. One heirloom variety of savoy is Bloomsdale. Bloomsdale is also somewhat bolt resistant.
  • Flat/smooth leaf spinach has broad smooth leaves that are easier to clean than savoy. This type is often grown for canned and frozen spinach, as well as soups, baby foods, and processed foods.
  • Semi-savoy is a hybrid variety. It has slightly crinkled leaves. It has the same texture as savoy, but it is not as difficult to clean. It is grown for both fresh market, and processing. Five Star is a widely grown variety and has good resistance to running up to seed.

Rosemary Stanton, in her Complete Book of Food and Nutrition, notes that silverbeet (or chard), is commonly referred to as spinach, particularly in Australia and New Zealand. Hence, there may be some popular confusion between the two vegetables.

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Purchasing

Spinach can be bought loosely or in prepackaged bags. You can get better quality when you buy loosely, because you can examine all the leaves. When examining the leaves, pick the ones that are smaller and have a good green color to them. Leaves that are crisp and spongy are of good quality. Do not pick leaves that are wilting, brown or yellow. Fresh spinach should smell sweet, never sour or musty. Look for stems that are fairly thin and coarse. Thick stems indicate overgrown spinach, which may be leathery and bitter. If only bagged spinach is available where you shop, check whether the contents seem resilient when you squeeze the bag.

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Storage

Spinach loses much of its nutritional value with storage of more than a few days. While refrigeration slows this effect to about eight days, spinach will lose most of its folate and carotenoid content. This is worth considering when purchasing spinach out of season. If the product has been "in transit" (picked, cleaned, shipped and shelved) for more than one or two days it will need to be used almost immediately to have much nutritional benefit. This is in spite of the taste and appearance of the plant which may still seem fine.

Fresh spinach should be cleaned thoroughly and then can be stored loosely in an unsealed bag in the crisper tray of the refrigerator for a few days. Even at 4°C, spinach loses much of its nutritional value by eight days so for longer storage it should be fresh frozen, cooked and frozen or canned. Storage in the freezer can be for up to eight months.


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Other species called spinach

The name spinach has been applied to a number of leaf vegetables, both related and unrelated to spinach:

Related species
  • Chard (Beta vulgaris, Amaranthaceae), also known as spinach beet or perpetual spinach.
  • Orache (Atriplex species, Amaranthaceae), also called "French spinach" or "mountain spinach".
  • Good King Henry (Chenopodium bonus-henricus, Amaranthaceae) and other Chenopodium species, also called "Lincolnshire spinach".
Unrelated species
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References and external links

Template:Commons Template:Cookbookbg:Спанак de:Spinat es:Spinacia oleracea fr:Épinard ko:시금치 it:Spinacia oleracea lb:Päinetsch lt:Špinatas ms:Bayam nl:Spinazie ja:ホウレンソウ pl:Szpinak pt:Espinafre fi:Pinaatti sv:Spenat zh:菠菜

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