The garlic plant's bulb is the most commonly used part of the plant. With the exception of the single clove types, garlic bulbs are normally divided into numerous fleshy sections called cloves. Garlic cloves are used for consumption (raw or cooked) or for medicinal purposes. They have a characteristic pungent, spicy flavor that mellows and sweetens considerably with cooking.[17]
Other parts of the garlic plant are also edible. The leaves and flowers (bulbils) on the head (spathe) are sometimes eaten. They are milder in flavor than the bulbs,[2] and are most often consumed while immature and still tender. Immature garlic is sometimes pulled, rather like a scallion, and sold as "green garlic".[18] When green garlic is allowed to grow past the "scallion" stage, but not permitted to fully mature, it may produce a garlic "round", a bulb like a boiling onion, but not separated into cloves like a mature bulb.[19] Additionally, the immature flower stalks (scapes) of the hardneck and elephant types are sometimes marketed for uses similar to asparagus in stir-fries.[6]
Inedible or rarely eaten parts of the garlic plant include the "skin" and root cluster. The papery, protective layers of "skin" over various parts of the plant are generally discarded during preparation for most culinary uses, though in Korea immature whole heads are sometimes prepared with the tender skins intact.[20] The root cluster attached to the basal plate of the bulb is the only part not typically considered palatable in any form.
Garlic is a fundamental component in many or most dishes of various regions, including eastern Asia, South Asia, Southeast Asia, the Middle East, northern Africa, southern Europe, and parts of South and Central America. The flavour varies in intensity and aroma with the different cooking methods. It is often paired with onion, tomato, or ginger. The parchment-like skin is much like the skin of an onion, and is typically removed before using in raw or cooked form. An alternative is to cut the top off the bulb, coat the cloves by dribbling olive oil (or other oil-based seasoning) over them, and roast them in an oven. Garlic softens and can be extracted from the cloves by squeezing the (root) end of the bulb, or individually by squeezing one end of the clove. In Korea, heads of garlic are fermented at high temperature; the resulting product, called black garlic, is sweet and syrupy, and is now being sold in the United States, United Kingdom and Australia.
Garlic may be applied to breads to create a variety of classic dishes, such as garlic bread, garlic toast, bruschetta, crostini and canapé.
Oils can be flavored with garlic cloves. These infused oils are used to season all categories of vegetables, meats, breads and pasta.
In some cuisines, the young bulbs are pickled for three to six weeks in a mixture of sugar, salt, and spices. In eastern Europe, the shoots are pickled 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 the cloves. They are often used in stir frying or braised like asparagus.[14] Garlic leaves are a popular vegetable in many parts of Asia. The leaves are cut, cleaned, and then stir-fried with eggs, meat, or vegetables.
Mixing garlic with egg yolks and olive oil produces aioli. Garlic, oil, and a chunky base produce skordalia. Blending garlic, almond, oil, and soaked bread produces ajoblanco.
Garlic powder has a different taste from fresh garlic. If used as a substitute for fresh garlic, 1/8 teaspoon of garlic powder is equivalent to one clove of garlic.
[edit] Storage
Garlic is often kept in oil to produce flavoured oil; however, the practice requires measures to be taken to prevent the garlic from spoiling. Untreated garlic kept in oil can support the growth of Clostridium botulinum which causes the deadly botulism illness; refrigeration will not assure the safety of garlic kept in oil. To reduce this risk, the oil should be refrigerated and used within one week. Commercially prepared oils are widely available. Manufacturers add acids and/or other chemicals to eliminate the risk of botulism in their products.[23] Two outbreaks of botulism related to garlic stored in oil have been reported.[24][25]
[edit] Historical use
Garlic has been used as both food and medicine in many cultures for thousands of years, dating at least as far back as when the Giza pyramids were built. Garlic is still grown in Egypt, but the Syrian variety is the kind most esteemed now (see Rawlinson's Herodotus, 2.125).Garlic is mentioned in the Bible and the Talmud. Hippocrates, Galen, Pliny the Elder, and Dioscorides all mention the use of garlic for many conditions, including parasites, respiratory problems, poor digestion, and low energy. Its use in China was first mentioned in AD 510.
It was consumed by 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' 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 for the heat of the sun in field labor.
In the account of Korea's establishment as a nation, gods were said to have given mortal women with bear and tiger temperaments an immortal's black garlic before mating with them.[citation needed][vague] This is a genetically unique, six-clove garlic that was to have given the women supernatural powers and immortality. This garlic is still cultivated in a few mountain areas today.
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.
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 meant the development of small, less potent bulbs).
[edit] Medicinal use and health benefits
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 623 kJ (149 kcal) |
| Carbohydrates | 33.06 g |
| - Sugars | 1.00g |
| - Dietary fiber | 2.1 g |
| Fat | 0.5 g |
| Protein | 6.39 g |
| - beta-carotene | 5 μg (0%) |
| Thiamine (vit. B1) | 0.2 mg (17%) |
| Riboflavin (vit. B2) | 0.11 mg (9%) |
| Niacin (vit. B3) | 0.7 mg (5%) |
| Pantothenic acid (B5) | 0.596 mg (12%) |
| Vitamin B6 | 1.235 mg (95%) |
| Folate (vit. B9) | 3 μg (1%) |
| Vitamin C | 31.2 mg (38%) |
| Calcium | 181 mg (18%) |
| Iron | 1.7 mg (13%) |
| Magnesium | 25 mg (7%) |
| Phosphorus | 153 mg (22%) |
| Potassium | 401 mg (9%) |
| Sodium | 17 mg (1%) |
| Zinc | 1.16 mg (12%) |
| Manganese 1.672 mg | |
| Selenium 14.2 μg | |
| Percentages are relative to US recommendations for adults. Source: USDA Nutrient Database | |
In in vitro studies, garlic has been found to have antibacterial, antiviral, and antifungal activity. However, these actions are less clear in vivo. Garlic is also claimed to help prevent heart disease (including atherosclerosis, high cholesterol, and high blood pressure) and cancer.[28] Garlic is used to prevent certain types of cancer, including stomach and colon cancers. In fact, countries where garlic is consumed in higher amounts, because of traditional cuisine, have been found to have a lower prevalence of cancer.[29] Animal studies, and some early research studies in humans, have suggested possible cardiovascular benefits of garlic. A Czech study found garlic supplementation reduced accumulation of cholesterol on the vascular walls of animals.[30] Another study had similar results, with garlic supplementation significantly reducing aortic plaque deposits of cholesterol-fed rabbits.[31] Another study showed supplementation with garlic extract inhibited vascular calcification in human patients with high blood cholesterol.[32] The known vasodilative effect of garlic is possibly caused by catabolism of garlic-derived polysulfides to hydrogen sulfide in red blood cells (RBCs), a reaction that is dependent on reduced thiols in or on the RBC membrane. Hydrogen sulfide is an endogenous cardioprotective vascular cell-signaling molecule.[33]
A randomized clinical trial funded by the National Institutes of Health (NIH) in the United States and published in the Archives of Internal Medicine in 2007 found the consumption of garlic in any form did not reduce blood cholesterol levels in patients with moderately high baseline cholesterol levels.[34][35] According to 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". In an editorial regarding the initial report's findings, two physicians from Weill Cornell Medical College of Cornell University, pointed out that there may "be effects of garlic on atherosclerosis specifically that were not picked up in the study".[36]
Allium sativum has been found to reduce platelet aggregation[37][38][39][40] and hyperlipidemia.[40][41][42]
In 2007, the BBC reported Allium sativum may have other beneficial properties, such as preventing and fighting the common cold.[43] This assertion has the backing of long tradition in herbal medicine, which has used garlic for hoarseness and coughs.[44] The Cherokee also used it as an expectorant for coughs and croup.[45]
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 been shown to prevent some complications of diabetes mellitus.[46][47] People taking insulin should not consume medicinal amounts of garlic without consulting a physician.
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.[48] More recently, it has been found from a clinical trial that a mouthwash containing 2.5% fresh garlic shows good antimicrobial activity, although the majority of the participants reported an unpleasant taste and halitosis.[49]
Garlic cloves are used as a remedy for infections (especially chest problems), digestive disorders, and fungal infections such as thrush.[50][51] Garlic can be used as a disinfectant because of its bacteriostatic and bacteriocidal properties.[4]
Garlic has been found to enhance thiamin absorption, and therefore reduces the likelihood for developing the thiamin deficiency beriberi.[52]
In 1924, it was found to be an effective way to prevent scurvy, because of its high vitamin C content.[52]
Garlic has been used reasonably successfully in AIDS patients to treat Cryptosporidium in an uncontrolled study in China.[53] It has also been used by at least one AIDS patient to treat toxoplasmosis, another protozoal disease.[54]
Garlic supplementation has been shown to boost testosterone levels in rats fed a high protein diet.[55]
A 2010 double-blind, parallel, randomised, placebo-controlled trial, involving 50 patients whose routine clinical records in general practice documented treated but uncontrolled hypertension, concluded, "Our trial suggests that aged garlic extract is superior to placebo in lowering systolic blood pressure similarly to current first line medications in patients with treated but uncontrolled hypertension."[56]
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