| Almond | |
|---|---|
| Almond tree with ripening fruit. Majorca, Spain. | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Rosales |
| Family: | Rosaceae |
| Genus: | Prunus |
| Subgenus: | Amygdalus |
| Species: | P. dulcis |
| Binomial name | |
| Prunus dulcis (Mill.) D.A.Webb |
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The almond (Prunus dulcis, syn. Prunus amygdalus Batsch., Amygdalus communis L., Amygdalus dulcis Mill.), is a species of tree native to the Middle East and South Asia. Almond is also the name of the edible and widely cultivated seed of this tree. Within the genus Prunus, it is classified with the peach in the subgenus Amygdalus, distinguished from the other subgenera by the corrugated shell (endocarp) surrounding the seed.
The fruit of the almond is not a true nut, but a drupe, consisting of an outer hull and a hard shell with the seed ("nut") inside. Shelling almonds refers to removing the shell to reveal the seed. Almonds are commonly sold shelled (i.e., after the shells are removed), or unshelled (i.e., with the shells still attached). Blanched almonds are shelled almonds that have been treated with hot water to soften the seedcoat, which is then removed to reveal the white embryo.
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The almond is a small deciduous tree, growing 4–10 metres (13–33 ft) in height, with a trunk of up to 30 centimetres (12 in) in diameter. The young twigs are green at first, becoming purplish where exposed to sunlight, then grey in their second year. The leaves are 3–5 inches long,[1] with a serrated margin and a 2.5 cm (1 in) petiole. The flowers are white or pale pink, 3–5 cm (1–2 in) diameter with five petals, produced singly or in pairs before the leaves in early spring.[2][3]
Almonds begin bearing an economic crop in the third year after planting. Trees reach full bearing after five to six years after planting. The fruit is mature in the autumn, 7–8 months after flowering.[3][4]
In botanical terms, the almond fruit is not a nut, but a drupe 3.5–6 cm (1–2 in) long. The outer covering or exocarp, fleshy in other members of Prunus such as the plum and cherry, is instead a thick leathery grey-green coat (with a downy exterior), called the hull. Inside the hull is a reticulated hard woody shell (like the outside of a peach pit) called the endocarp. Inside the shell is the edible seed, commonly called a nut. Generally, one seed is present, but occasionally there are two.
The almond is a native to the Mediterranean climate region of the Middle East, eastward as far as the Indus.[5] It was spread by humans in ancient times along the shores of the Mediterranean into northern Africa and southern Europe and more recently transported to other parts of the world, notably California, United States.[5]
The wild form of domesticated almond grows in parts of the Levant; almonds must first have been taken into cultivation in this region. The fruit of the wild forms contains the glycoside amygdalin, "which becomes transformed into deadly prussic acid (hydrogen cyanide) after crushing, chewing, or any other injury to the seed."[6]
However, domesticated almonds are not toxic; Jared Diamond argues that a common genetic mutation causes an absence of glycoside amygdalin, and this mutant was grown by early farmers, "at first unintentionally in the garbage heaps, and later intentionally in their orchards".[7] Zohary and Hopf believe that almonds were one of the earliest domesticated fruit trees due to "the ability of the grower to raise attractive almonds from seed. Thus, in spite of the fact that this plant does not lend itself to propagation from suckers or from cuttings, it could have been domesticated even before the introduction of grafting".[6] Domesticated almonds appear in the Early Bronze Age (3000–2000 BC) of the Near East, or possibly a little earlier. A well-known archaeological example of the almond is the fruit found in Tutankhamun's tomb in Egypt (c. 1325 BC), probably imported from the Levant.[6] Of the European countries that the Royal Botanic Garden Edinburgh reported as cultivating almonds, Germany[8] is the northernmost, though the domesticated form can be found as far north as Iceland.[9]
The word "almond" comes from Old French almande or alemande, Late Latin amandola, derived through a form amingdolouhha from the Greek αμυγδαλη (cf amygdala), an almond. The al- in English, for the a- used in other languages may be due a confusion with the Arabic article al, the word having first dropped the a- as in the Italian form mandorla; the British pronunciation ah-mond and the modern Catalan ametlla and modern French amande show a form of the word closer to the original.
The adjective amygdaloid (literally "like an almond") is used to describe objects which are roughly almond-shaped, particularly a shape which is part way between a rectangle and an ellipse. See, for example, the brain structure amygdala, which uses a direct borrowing of the Greek term.
Global production of almonds is around 1.7 million tonnes, with a low of 1 million tonnes in 1995 and a peak of 1.85 million tonnes in 2002 according to Food and Agriculture Organization (FAO) figures; world production of almonds was 1.76 million tonnes in 2006.[10] According to the FAO, major producers are the USA (715,623 t, 41%), Spain (220,000 t, 13%), Syria (119,648 t, 7%), Italy (112,796 t, 6%), Iran (108,677 t, 6%) and Morocco (83,000 t, 5%). Algeria, Tunisia, and Greece each account for 3%, Turkey, Pakistan, Lebanon, and China each account for 2%.[11] In Turkey, most of the production comes from the Datça Peninsula. In Spain, numerous commercial cultivars of sweet almond are produced, most notably the Jordan almond (imported from Málaga) and the Valencia almond.
In Greece, most of the production comes from the Thessalia, in region of Magnesia at the area of Almyros. The most cultivating types of almonds in Greece are ferragnes and Texas (mission) which are known for their sweet taste and premium quality. Because of its quality, it is used as a luxury nut.
In the United States, production is concentrated in California, with almonds being California's third leading agricultural product and its top agricultural export in 2008. California produces 80% of the world’s almonds[12] and 100% of the U.S. commercial supply. California exported almonds valued at $1.08 billion in 2003, about 70% of total California almond crop.
[13]
The top 10 almond production countries in 2009 according to FAO in tonnes
The pollination of California's almonds is the largest annual managed pollination event in the world, with close to one million hives (nearly half of all beehives in the USA) being trucked in February to the almond groves. Much of the pollination is managed by pollination brokers, who contract with migratory beekeepers from at least 49 states for the event. This business has been heavily impacted by colony collapse disorder, causing nationwide shortages of honey bees and increasing the price of insect pollination. To alleviate almond growers from the rising cost of insect pollination, researchers at the Agricultural Research Service (ARS) have developed a new line of self-pollinating almond trees.[14] Self-pollinating almond trees, such as the Tuono almond tree, have been around for a while, but their harvest is not as desirable as the insect-pollinated California Nonpareil almond tree. The Nonpareil tree produces large, smooth almonds and offer 60–65% edible kernel per nut. The Tuono, on the other hand, has thicker, hairier shells and offers only 32% of edible kernel per nut. However, there are advantages to having a thick shell. The Tuono’s shell protects the nut from threatening pests such as the navel orangeworm. ARS researchers have managed to cross breed the pest-resistant Tuono tree with California’s attractive Nonpareil tree, resulting in hybridized varieties of almond trees that are self-pollinated and maintain a high quality of nut.[15] The new, self-pollinating almond tree hybrids possess quality skin color, flavor, and oil content, and reduce almond growers’ dependency on insect pollination.[14]
The fruit of Prunus dulcis is predominately sweet, but a few bitter almonds may be found on each tree.[16][17] The fruits from Prunus dulcis var. amara are always bitter as are the kernels from other Prunus species like apricot, peach and cherry (to a lesser extent).
The bitter almond is slightly broader and shorter than the sweet almond, and contains about 50% of the fixed oil that occurs in sweet almonds. It also contains the enzyme emulsin which, in the presence of water, acts on a soluble glucoside, amygdalin, yielding glucose, cyanide and the essential oil of bitter almonds, which is nearly pure benzaldehyde. Bitter almonds may yield from 4–9 mg of hydrogen cyanide per almond.[18][19] Extract of bitter almond was once used medicinally, but even in small doses, effects are severe, and in larger doses can be deadly; the cyanide must be removed before consumption.[20]
While the almond is often eaten on its own, raw or toasted, it is also a component of various dishes. Almonds are available in many forms, such as whole, sliced (flaked, slivered), and as almond butter, almond milk and almond oil. These variations can be used in both sweet and savory dishes.
Along with other nuts, sweet almonds can be sprinkled over desserts, particularly ice cream based dishes. Sweet almonds are used in marzipan, nougat, many pastries (including jesuites), cookies (including French macarons, macaroons), and cakes (including financiers), noghl and other sweets and desserts. They are also used to make almond butter, a spread similar to peanut butter, popular with peanut allergy sufferers and for its less salty taste. The young, developing fruit of the almond tree can be eaten whole ("green almonds") when they are still green and fleshy on the outside and the inner shell has not yet hardened. The fruit is somewhat sour, but is a popular snack in parts of the Middle East, eaten dipped in salt to balance the sour taste. Available only from mid April to mid June (northern hemisphere), pickling or brining extends the fruit's shelf life.
Almonds can be processed into a milk substitute called almond milk; the nut's soft texture, mild flavour, and light colouring (when skinned) make for an efficient analog to dairy, and a soy-free choice for lactose intolerant people and vegans. Raw, blanched, and lightly toasted almonds work well for different production techniques, some of which are similar to that of soymilk and some of which use no heat, resulting in "raw milk" (see raw foodism).
The 'Marcona' almond cultivar is recognizably different from other almonds, and is marketed by name.[23] The kernel is short, round, relatively sweet and delicate in texture. It has been grown in Spain for a long time and its origin is unknown; the tree is very productive, the shell of the nut very hard.[23] 'Marcona' almonds are traditionally served after being lightly fried in oil, and are used by Spanish chefs to prepare a dessert called turrón.
Almond flour is often used as a gluten-free alternative to wheat flour in cooking and baking.[24]
Historically, almond syrup was an emulsion of sweet and bitter almonds, usually made with barley syrup (orgeat syrup) or in a syrup of orange flower water and sugar.
The Grocer's Encyclopedia (1911) notes that "Ten parts of sweet almonds are generally employed to three parts of bitter almonds"; however, due to the cyanide found in bitter almonds, modern syrups generally consist of only sweet almonds.
Almonds contain approximately 49% oils, of which 62% is monounsaturated oleic acid (an omega-9 fatty acid), 24% is linoleic acid (a polyunsaturated omega-6 essential fatty acid), and 6% is palmitic acid (a saturated fatty acid).[25]
"Oleum Amygdalae", the fixed oil, is prepared from either variety of almond and is a glyceryl oleate, with a slight odour and a nutty taste. It is almost insoluble in alcohol but readily soluble in chloroform or ether. Sweet almond oil is obtained from the dried kernel of sweet almonds.
The oil is good for application to the skin as an emollient, and has been traditionally used by massage therapists to lubricate the skin during a massage session. It is a mild, lightweight oil that can be used as a substitute for olive oil.
Almond oil is also used as a wood conditioner of certain woodwind instruments, such as the oboe and clarinet.
This Almond oil is used to remove black spots and black marks on the skin.
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 2,418 kJ (578 kcal) |
| Carbohydrates | 20 g |
| - Sugars | 5 g |
| - Dietary fibre | 12 g |
| Fat | 51 g |
| - saturated | 4 g |
| - monounsaturated | 32 g |
| - polyunsaturated | 12 g |
| Protein | 22 g |
| Thiamine (vit. B1) | 0.24 mg (21%) |
| Riboflavin (vit. B2) | 0.8 mg (67%) |
| Niacin (vit. B3) | 4 mg (27%) |
| Pantothenic acid (B5) | 0.3 mg (6%) |
| Vitamin B6 | 0.13 mg (10%) |
| Folate (vit. B9) | 29 μg (7%) |
| Vitamin C | 0.0 mg (0%) |
| Vitamin E | 26.22 mg (175%) |
| Calcium | 248 mg (25%) |
| Iron | 4 mg (31%) |
| Magnesium | 275 mg (77%) |
| Phosphorus | 474 mg (68%) |
| Potassium | 728 mg (15%) |
| Zinc | 3 mg (32%) |
| Percentages are relative to US recommendations for adults. Source: USDA Nutrient Database |
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The sweet almond contains about 26% carbohydrates (12% dietary fiber, 6.3% sugars, 0.7% starch and the rest miscellaneous carbohydrates), and may therefore be made into flour for cakes and cookies (biscuits) for low-carbohydrate diets. A standard serving of almond flour, 1 cup, contains 20 grams of carbohydrates, of which 10 g is dietary fiber, for a net of 10 g of carbohydrate per cup. This makes almond flour very desirable for use in cake and bread recipes by people on carbohydrate-restricted diets.
Almonds are a rich source of vitamin E, containing 26 mg per 100 g (Table). They are also rich in dietary fiber, B vitamins, essential minerals and monounsaturated fat (see nutrient table), one of the two "good" fats which potentially may lower LDL cholesterol. Typical of nuts and seeds, almonds also contain phytosterols, associated with cholesterol-lowering properties.
Potential health benefits, which have not been scientifically validated, include improved complexion and possibly a lower risk of cancer.[26] Preliminary research associates consumption of almonds with elevating blood levels of high density lipoproteins and lowering low density lipoproteins.[27][28] A preliminary trial showed that, in spite of the high fat content of almonds, using them in the daily diet might lower several factors associated with heart disease, including cholesterol and blood lipids.[29]
Almonds contain polyphenols in their skins[30] analogous to those of certain fruits and vegetables.
Almonds may cause allergy or intolerance. Cross-reactivity is common with peach allergens (lipid transfer proteins) and tree nut allergens. Symptoms range from local symptoms (e.g., oral allergy syndrome, contact urticaria) to systemic symptoms including anaphylaxis (e.g., urticaria, angioedema, gastrointestinal and respiratory symptoms).[31]
| Amino Acids | g/100g Nuts |
|---|---|
| Tryptophan | 0.19 |
| Threonine | 0.68 |
| Lysine | 0.60 |
| Leucine | 1.47 |
| Isoleucine | 0.69 |
| Methionine | 0.19 |
| Cysteine | 0.28 |
| Phenylalanine | 1.15 |
| Tyrosine | 0.53 |
| Valine | 0.80 |
| Arginine | 2.47 |
| Tyrosine | 0.53 |
Because of two cases of salmonellosis traced to almonds in 2001 and 2004, the Almond Board of California proposed rules in 2006 regarding pasteurization of almonds available to the public, and the USDA approved them. The almond pasteurization program became mandatory for the California industry on September 1, 2007, and was implemented voluntarily over the previous two years.[32] Since September 1, 2007, raw untreated California almonds have technically not been available in the United States. Controversially, California almonds labeled as "raw" are required to be steam-pasteurized or chemically treated with propylene oxide. This does not apply to imported almonds,[33] or to almonds sold from the grower directly to the consumer in small quantities.[34] Nor is the treatment required for raw almonds sold as exports to countries outside of North America.
This USDA-approved marketing order has been challenged in court by organic farmers organized by the Cornucopia Institute, a Wisconsin-based farm policy research group. According to the Cornucopia Institute, this almond marketing order has imposed significant financial burdens on small-scale and organic growers and damaged domestic almond markets. The federal judge dismissed the lawsuit in the spring of 2009 on procedural grounds, but farmers are appealing this decision in August 2009, seeking to have the merits of their arguments heard in court.[35]
The almond is highly revered in some cultures. In northern Indian state, Jammu and Kashmir, it is designated as the state tree of Kashmir.
The tree grows in Lebanon, Syria and Israel,[36] and is mentioned numerous times in the Bible.
In the Old Testament, the almond was a symbol of watchfulness and promise due to its early flowering, symbolizing God's sudden and rapid punishment of His people; in Jeremiah 1:11–12, for instance. In the Bible the almond is mentioned ten times, beginning with Book of Genesis 43:11, where it is described as "among the best of fruits". In Numbers 17 Levi is chosen from the other tribes of Israel by Aaron's rod, which brought forth almond flowers. According to tradition, the rod of Aaron bore sweet almonds on one side and bitter on the other; if the Israelites followed the Lord, the sweet almonds would be ripe and edible, but if they were to forsake the path of the Lord, the bitter almonds would predominate. The almond blossom supplied a model for the menorah which stood in the Holy Temple, "Three cups, shaped like almond blossoms, were on one branch, with a knob and a flower; and three cups, shaped like almond blossoms, were on the other...on the candlestick itself were four cups, shaped like almond blossoms, with its knobs and flowers" (Exodus 25:33–34; 37:19–20). Similarly, Christian symbolism often uses almond branches as a symbol of the Virgin Birth of Jesus; paintings often include almonds encircling the baby Jesus and as a symbol of Mary. The word "Luz", which appears in Genesis 30:37, is sometimes translated as "hazel", may actually be derived from the Aramaic name for almond (Luz), and is translated as such in some Bible versions such as the NIV.[37]
In India, consumption of almonds is believed to be good for the brain, while the Chinese consider it a symbol of enduring sadness and female beauty.
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