Garlic

Garlic
File:Allium sativum plant.jpg
Allium sativum, known as garlic
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Liliopsida
Order:	Asparagales
Family:	Alliaceae
Subfamily:	Allioideae
Tribe:	Allieae
Genus:	Allium
Species:	A. sativum
Binomial name
Allium sativum L.

Allium sativum L., commonly known as garlic, is a species in the onion family Alliaceae. Its close relatives include the onion, shallot, and leek. Garlic has been used throughout recorded history for both culinary and medicinal purposes. It has a characteristic pungent, 'hot', flavour that mellows and sweetens considerably with cooking. A 'head' of garlic, the most commonly used plant part, comprises numerous discrete 'cloves'. The leaves and stems are sometimes eaten, particularly while immature and tender.

Vernacular names

• Garlic (English)
• Aglio (Italian)
• Ail (French)
• Alho (Portuguese)
• Kitunguu saumu, somu, thumu (Swahili)
• Poondu (பூண்டு) in Tamil
• Ajo in Spanish
• Hvitløk (Norwegian)
• Hvidløg (Danish)
• Vitlök (Swedish)
• Knoblauch (German)
• Cesnak (Slovakian)
• Knoflook (Dutch)

Origin and distribution

The ancestry of cultivated garlic, according to Zohary and Hopf, is not definitely established: "a difficulty in the identifiaction of its wild progenitor is the sterility of the cultivars." It is believed to originate from Central Asia (Kazakhstan, Uzbekistan and western China). This was confirmed by phylogenetic analysis based on molecular and biochemical markers, also indicating a secondary diversity centre in the Caucasus. Garlic spread to the Mediterranean in ancient times. It was already grown in Egypt in 1600 BC and is an ancient crop in India and China as well. At present garlic is grown all over the world from the equator to latitudes of 50° in both hemispheres, but is most popular in China, the Mediterranean and Latin America. In tropical Africa, garlic is grown during the cold season in the Sahel and at high elevations in East and southern Africa. It is a popular crop in the savanna zone, with a wide genetic variation in local cultivars. It is rarely, if ever, found in hot and humid lowlands.

Allium sativum grows in the wild in areas where it has become naturalised; it probably descended from the species Allium longicuspis, which grows wild in south-western Asia. The 'wild garlic', 'crow garlic' and 'field garlic' of Britain are the species Allium ursinum, Allium vineale and Aleum oleraceum, respectively. In North America, 'Allium vineale, known as 'wild-' or 'crow garlic', and Allium candadensis, known as 'meadow-' or 'wild garlic', are common weeds in fields.

Uses around the world

After onion, garlic is the second most widely used cultivated Allium. The bulbs, composed of bulblets tightly packed around the previous season's stalk, whose easily divisable character has led to their being called "cloves", are mainly used for flavouring meat, fish, sauces and salads, raw or cooked, or more recently in dehydrated form. Apart from bulbs, the young floral stems are also used in Spain, China and Indonesia, and whole young green plants are used too. Garlic is much valued as a phyto-therapeutic crop. Garlic users, including many African people, extol its taste and health qualities. Crushed raw garlic is strongly antibiotic, and it has a reputation for lowering blood pressure and inhibiting thrombus formation, though its reputation in urban mythology for lowering cholesterol has been disproven.. Leaves and bulbs are considered to have hypotensive, carminative, antiseptic, anthelmintic, diaphoretic and expectorant properties. Several attributed prophylactic qualities are questionable, but have resulted in a rich supply of and demand for medicinal pills, drinks and powders based on garlic extracts.

Engraving of the Allium sativum plant, showing the head (bottom left), leaf, stem, and flower. From William Woodville, Medical Botany, 1793.

Culinary uses

Garlic being crushed using a Garlic press.

Garlic bulbs and individual cloves, one peeled.

Garlic is widely used around the world for its pungent flavour, as a seasoning or condiment or to enhance other flavours. Depending on the form of cooking and the desired result, the flavor is either mellow or intense. It is often paired with onion, tomato, and/or ginger. It is very widely used in Lebanese cuisine: many Lebanese salads contain a garlic sauce. The parchment-like skin is relatively inedible, much like the skin of an onion. The skin is typically removed before cooking, though sometimes alternative approaches are used, such as slice garlic head crosswise, coat in olive oil, roast until the garlic is well cooked, and then the roasted garlic separates quite easily from the skins (by pulling it out, shaking it out, and/or squeezing it out). The term 'clove' is sometimes misinterpreted to mean the whole garlic bulb (head).

Garlic is commonly stored in cooking oil with herbs to yield an oil infused with flavour. Garlic-infused oils are widely available. Care must be taken preparing such, as there is a risk of botulism developing in the oxygen-free oil if the product is not stored properly. To reduce the risk of botulism, the oil containing the garlic must be refrigerated and used within one week. (see Caution below). Commercial producers use a combination of salts and/or acids to eliminate the risk of botulism in their products. In Chinese cuisine, the young bulbs are pickled for 3-6 weeks in a mixture of sugar, salt and spices. Pickled garlic is available at supermarkets. The shoots are often pickled in Russia and states of the Caucasus and eaten as an appetizer.

Immature scapes are tender and edible. They are also known as 'garlic spears', 'stems', or 'tops'. Scapes generally have a milder taste than cloves. They are often used in stir frying or prepared like asparagus. Garlic leaves are a popular vegetable in many parts of Asia, particularly in particular Chinese, Vietnamese, and Cambodian. The leaves are cut, cleaned and then stir-fried with eggs, meat or vegetables.

Historical use

From the earliest times garlic has been used as a food. It formed part of the food of the Israelites in Egypt (Numbers 11:5) and of the labourers employed by Khufu in constructing the pyramid. Garlic is still grown in Egypt, but the Syrian variety is the kind most esteemed now (see Rawlinson's Herodotus, 2.125).

It was consumed by the ancient Greek and Roman soldiers, sailors and rural classes (Virgil, Ecologues ii. 11), and, according to Pliny the Elder (Natural History xix. 32), by the African peasantry. Galen eulogizes it as the "rustic's theriac" (cure-all) (see F Adams's Paulus Aegineta, p. 99), and Alexander Neckam, a writer of the 12th century (see Wright's edition of his works, p. 473, 1863), recommends it as a palliative of the heat of the sun in field labor.

In his Natural History Pliny gives an exceedingly long list of scenarios in which it was considered beneficial (N.H. xx. 23). Dr. T. Sydenham valued it as an application in confluent smallpox, and, says Cullen (Mat. Med. ii. p. 174, 1789), found some dropsies cured by it alone. Early in the 20th century, it was sometimes used in the treatment of pulmonary tuberculosis or phthisis.

Garlic was rare in traditional English cuisine (though it is said to have been grown in England before 1548), and has been a much more common ingredient in Mediterranean Europe. Garlic was placed by the ancient Greeks on the piles of stones at cross-roads, as a supper for Hecate (Theophrastus, Characters, The Superstitious Man); and according to Pliny, garlic and onions were invoked as deities by the Egyptians at the taking of oaths. The inhabitants of Pelusium in lower Egypt, who worshipped the onion, are said to have had an aversion to both onions and garlic as food.

To prevent the plant from running to leaf, Pliny (N.H. xix. 34) advised bending the stalk downward and covering with earth; seeding, he observes, may be prevented by twisting the stalk (by "seeding", he most likely means the development of small, less potent bulbs).

Medicinal use

Today garlic is used to help prevent heart disease, including atherosclerosis, high cholesterol, high blood pressure, and to improve the immune system. Garlic may also protect against cancer.

A report published by the "Archives of Internal Medicine", on 26 February 2007, found that consumption of garlic, in any form, did not reduce cholesterol levels in patients with moderately high levels.

However as reported in Heart.org, "Despite decades of research suggesting that garlic can improve cholesterol profiles, a new NIH-funded trial found absolutely no effects of raw garlic or garlic supplements on LDL, HDL, or triglycerides. The findings underscore the hazards of meta-analyses made up of small, flawed studies and the value of rigorously studying popular herbal remedies".

While a BBC news story reported that Allium sativum may have beneficial properties, such as preventing and fighting the common cold, garlic has been used as both food and medicine in many cultures for thousands of years, dating as far back as the time that the Egyptian pyramids were built.

Allium sativum has been found to reduce platelet aggregation and hyperlipidaemia.

Garlic is also alleged to help regulate blood sugar levels. Regular and prolonged use of therapeutic amounts of aged garlic extracts lower blood homocysteine levels, and has shown to prevent some complications of diabetes mellitus. People taking insulin should not consume medicinal amounts of garlic without consulting a physician. In such applications, garlic must be fresh and uncooked, or the allicin will be lost.

Allium sativum may also possess cancer-fighting properties due to the presence of diallyl sulphide (DADs), believed to be an anticarcinogen.

Decocted garlic extracts that are left to set overnight are very effective in healing wounds. In 1858, Louis Pasteur observed garlic's antibacterial activity, and it was used as an antiseptic to prevent gangrene during World War I and World War II.

In modern naturopathy, garlic is used as a treatment for intestinal worms and other intestinal parasites, both orally and as an anal suppository. Garlic cloves are used as a remedy for infections (especially chest problems), digestive disorders, and fungal infections such as thrush. Whole cloves used as vaginal suppositories are sometimes used as a home remedy for Candidiasis (yeast infections).

Garlic supplementation in rats along with a high protein diet has been shown to boost testosterone levels

Dietary supplements in an "odourless" pill form, as are commonly available, claim to possess the medicinal benefits of garlic, without (in the words of one manufacturer) "the unsocial qualities associated with fresh garlic cloves".

Properties

When crushed, Allium sativum yields allicin, a powerful antibiotic and anti-fungal compound (phytoncide). It also contains alliin, ajoene, enzymes, vitamin B, minerals, and flavonoids.

The percentage composition of the bulbs is given by E. Solly (Trans. Hon. Soc. Loud., new ser., iii. p. 60) as water 84.09%, organic matter 13.38%, and inorganic matter 1.53% - that of the leaves being water 87.14%, organic matter 11.27% and inorganic matter 1.59%.

File:Czosnek2 1511.jpg

Garlic flowerhead

The phytochemicals responsible for the sharp flavor of garlic are produced when the plant's cells are damaged. When a cell is broken by chopping, chewing, or crushing, enzymes stored in cell vacuoles trigger the breakdown of several sulfur-containing compounds stored in the cell fluids. The resultant compounds are responsible for the sharp or hot taste and strong smell of garlic. Some of the compounds are unstable and continue to evolve over time. Among the members of the onion family, garlic has by far the highest concentrations of initial reaction products, making garlic much more potent than onions, shallots, or leeks. Although people have come to enjoy the taste of garlic, these compounds are believed to have evolved as a defensive mechanism, deterring animals like birds, insects, and worms from eating the plant.

A large number of sulfur compounds contribute to the smell and taste of garlic. Diallyl disulfide is believed to be an important odour component. Allicin has been found to be the compound most responsible for the spiciness of raw garlic. This chemical opens thermoTRP (transient receptor potential) channels that are responsible for the burning sense of heat in foods. The process of cooking garlic removes allicin, thus mellowing its spiciness.

When eaten in quantity, garlic may be strongly evident in the diner's sweat and breath the following day. This is because garlic's strong smelling sulfur compounds are metabolized forming allyl methyl sulfide. Allyl methyl sulfide (AMS) cannot be digested and is passed into the blood. It is carried to the lungs and the skin where it is excreted. Since digestion takes several hours, and release of AMS several hours more, the effect of eating garlic may be present for a long time.

This well-known phenomenon of "garlic breath" is alleged to be alleviated by eating fresh parsley. The herb is, therefore, included in many garlic recipes, such as Pistou and Persillade. However, since the odour results mainly from digestive processes placing compounds such as AMS in the blood, and AMS is then released through the lungs over the course of many hours, eating parsley provides only a temporary masking. One way of accelerating the release of AMS from the body is the use of a sauna. Due to its strong odor, garlic is sometimes called the "stinking rose".

Superstition and mythology

Garlic has been regarded as a force for both good and evil. A Christian myth considers that after Satan left the Garden of Eden, garlic arose in his left footprint, and onion in the right. In Europe, many cultures have used garlic for protection or white magic, perhaps owing to its reputation as a potent preventative medicine. Central European folk beliefs considered garlic a powerful ward against demons, werewolves, and vampires. To ward off vampires, garlic could be worn, hung in windows or rubbed on chimneys and keyholes.

The association of garlic to evil spirits, may be based on the antibacterial, antiparasitic value of garlic, that can prevent infections that lead to delusions, and other related mental illness symptoms.

Cautions

• Cases of botulism have been caused by consuming garlic-in-oil preparations. It is important to add acid when creating these mixtures and to keep them refrigerated to retard bacterial growth.

• Whilst culinary quantities are considered safe during pregnancy and breastfeeding, extremely large quantities of garlic and garlic supplements have been linked with a raised risk of bleeding. Some breastfeeding mothers have found their babies slow to feed and have noted a garlic odour coming from their baby when they have consumed garlic.

• The side effects of long-term garlic supplementation, if any exist, are largely unknown and no FDA-approved study has been performed. However, garlic has been consumed for several thousand years without any adverse long-term effects, suggesting that modest quantities of garlic pose, at worst, minimal risks to normal individuals.

• There have been several reports of serious burns resulting from garlic being applied topically for various purposes, including naturopathic uses and acne treatment.

Trivia

• The city of Gilroy, California promotes itself as "Garlic Capital of the World", and hosts the three-day Gilroy Garlic Festival every summer.

• The two-day Hudson Valley Garlic Festival is held yearly in Saugerties, New York.

• In the televised cartoon shorts, before he used spinach as a source of superhuman strength, comic book character Popeye's ancestor Hercules would sniff fresh bulbs of unpeeled garlic.

References

Bibliography

• McGee, Harold (2004). On Food and Cooking (Revised Edition). Scribner. ISBN 0-684-80001-2. pp 310–313: The Onion Family: Onions, Garlic, Leeks.
• Salunkhe, D.K.; Kadam, S.S. (1998). Handbook of Vegetable Science and Technology. Marcel Dekker. ISBN 0-8247-0105-4.{{cite book}}: CS1 maint: multiple names: authors list (link)
• Koch, H. P.; Lawson, L. D. (1996). Garlic. The Science and Therapeutic Application of Allium sativum L. and Related Species (Second Edition). Williams & Wilkens. ISBN 0-683-18147-5.{{cite book}}: CS1 maint: multiple names: authors list (link)
• James Mellgren (2003).
• Hamilton, Andy (2004). Selfsufficientish - Garlic. Retrieved 1 May 2005.
• R. Kamenetsky, I. L. Shafir, H. Zemah, A. Barzilay, and H. D. Rabinowitch (2004). Environmental Control of Garlic Growth and Florogenesis. J. Am. Soc. Hort. Sci. 129: 144-151.
• Lindsey J. Macpherson, Bernhard H. Geierstanger, Veena Viswanath, Michael Bandell, Samer R. Eid, SunWook Hwang, and Ardem Patapoutian (2005). "The pungency of garlic: Activation of TRPA1 and TRPV1 in response to allicin". Current Biology. 15 (May 24): 929–934. {{cite journal}}: External link in |title= (help)CS1 maint: multiple names: authors list (link)
• Balch, P. A. (2000). Prescription for Nutritional Healing, 3rd ed. New York: Avery.
• Block, E. (1985). The chemistry of garlic and onions. Scientific American 252 (March): 114-119.
• Block, E. (1992). The organosulfur chemistry of the genus Allium — implications for organic sulfur chemistry. Angewandte Chemie International Edition 104: 1158-1203.
• Breithaupt-Grogler, K., et al. (1997). Protective effect of chronic garlic intake on elastic properties of aorta in the elderly. Circulation 96: 2649-2655. Abstract.
• Efendy, J. L., et al. (1997). The effect of the aged garlic extract, 'Kyolic', on the development of experimental atherosclerosis. Arterosclerosis 132: 37-42. Abstract.
• Hile, A. G.; Shan, Z.; Zhang, S.-Z.; Block, E. (2004). Aversion of European starlings (Sturnus vulgaris) to garlic oil treated granules: garlic oil as an avian repellent. Garlic oil analysis by nuclear magnetic resonance spectroscopy. Journal of Agricultural and Food Chemistry 52: 2192-2196. [2]
• Jain, A. K. (1993). Can garlic reduce levels of serum lipids? A controlled clinical study. American Journal of Medicine 94: 632-635. Abstract.
• Lawson, L. D.; Wang, Z. J. (2001). Low allicin release from garlic supplements: a major problem due to sensitivities of alliinase activity.Journal of Agricultural and Food Chemistry 49: 2592-2599. [3]
• Mader, F. H. (1990). Treatment of hyperlipidemia with garlic-powder tablets. Arzneimittel-Forschung/Drug Research 40 (2): 3-8. Abstract.
• Silagy, C., and Neil, A. (1994). Garlic as a lipid-lowering agent - a meta-analysis. Journal of the Royal College of Physicians 28 (1): 2-8. Abstract
• Steiner, M., and Lin, R.S. (1998). Changes in platelet function and susceptibility of lipoproteins to oxidation associated with administration of aged garlic extract. Journal of Cardiovascular Pharmacology 31: 904-908. Abstract
• Yeh, Y-Y., et al. (1999). Garlic extract reduces plasma concentration of homocysteine in rats rendered folic acid deficient. FASEB Journal 13(4): Abstract 209.12.
• Yeh, Y-Y., et al. (1997). Garlic reduced plasma cholesterol in hypercholesterolemic men maintaining habitual diets. In: Ohigashi, H., et al. (eds). Food Factors for Cancer Prevention. Tokyo: Springer-Verlag. Abstract. This is a meta-reference and includes 205 scientific and non-scientific papers from the United States National Library of Medicine [4].

External links

• Plant Resources of Tropical Africa
• PROTAbase
• Garlic: Plants For a Future database