Almond

Thealmond(Prunus amygdalus,syn.Prunus dulcis) is a species of tree from the genusPrunus. Along with thepeach, it is classified in the subgenusAmygdalus, distinguished from the other subgenera by corrugations on the shell (endocarp) surrounding the seed.
The fruit of the almond is adrupe, consisting of an outer hull and ahard shellwith the seed, which is not atrue nut.Shellingalmonds refers to removing the shell to reveal the seed. Almonds are sold shelled or unshelled.Blanchedalmonds are shelled almonds that have been treated with hot water to soften theseedcoat, which is then removed to reveal the whiteembryo. Once almonds are cleaned and processed, they can be stored for around a year if kept refrigerated; at higher temperatures they will becomerancidmore quickly.Almonds are used in many cuisines, often featuring prominently in desserts, such asmarzipan.
The almond tree prospers in a moderateMediterranean climatewith cool winter weather.It is rarely found wild in its original setting.Almonds were one of the earliest domesticatedfruit trees, due to the ability to produce quality offspring entirely from seed, without using suckers and cuttings. Evidence of domesticated almonds in theEarly Bronze Agehas been found in the archeological sites of the Middle East, and subsequently across the Mediterranean region and similar arid climates with cool winters.
California producesabout 80% of the world's almond supply.Due to high acreage and water demand for almond cultivation, and need forpesticides,California almond productionmay be unsustainable, especially during the persistent drought and heat fromclimate changein the 21st century.Droughts in Californiahave caused some producers to leave the industry, leading to lower supply and increased prices.
The almond is adeciduoustree growing to 3–4.5 metres (10–15 feet) in height,with a trunk of up to 30 centimetres (12 inches) in diameter. The youngtwigsare green at first, becoming purplish where exposed to sunlight, then grey in their second year. Theleavesare 8–13 cm (3–5 in) long,with a serrated margin and a 2.5 cm (1 in)petiole.
The fragrantflowersare white to pale pink, 3–5 cm (1–2 in) diameter with five petals, produced singly or in pairs and appearing before the leaves in early spring.Almond trees thrive in Mediterranean climates with warm, dry summers and mild, wet winters.The optimal temperature for their growth is between 15 and 30 °C (59 and 86 °F) and the tree buds have achilling requirementof 200 to 700 hours below 7.2 °C (45.0 °F) to break dormancy.
Almonds begin bearing an economic crop in the third year after planting. Trees reach full bearing five to six years after planting. The fruit matures in the autumn, 7–8 months after flowering.
The almond fruit is3.5–6 cm (1+3⁄8–2+3⁄8in) long. It is not anutbut adrupe. The outer covering, consisting of an outerexocarp, or skin, andmesocarp, or flesh, fleshy in other members ofPrunussuch as theplumandcherry, is instead a thick, leathery, grey-green coat (with a downy exterior), called the hull. Inside the hull is a woodyendocarpwhich forms a reticulated, hard shell (like the outside of a peach pit) called thepyrena. Inside the shell is the edible seed, commonly called a nut.Generally, one seed is present, but occasionally two occur. After the fruit matures, the hull splits and separates from the shell, and anabscission layerforms between the stem and the fruit so that the fruit can fall from the tree.During harvest, mechanised tree shakers are used to expedite fruits falling to the ground for collection.
The seeds ofPrunus dulcisvar.dulcisare predominantly sweetbut some individual trees produce seeds that are somewhat more bitter.The genetic basis for bitterness involves a single gene, the bitter flavour furthermore beingrecessive,both aspects making this trait easier to domesticate. The fruits fromPrunus dulcisvar.amaraare always bitter, as are the kernels from other species of genusPrunus, such as apricot, peach and cherry (although 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 enzymeemulsinwhich, in the presence of water, acts on the twosolubleglucosidesamygdalinandprunasinyieldingglucose,cyanideand theessential oilof bitter almonds, which is nearly purebenzaldehyde, the chemical causing the bitter flavour. Bitter almonds may yield 4–9 milligrams ofhydrogen cyanideper almondand contain 42 times higher amounts of cyanide than the trace levels found in sweet almonds.The origin of cyanide content in bitter almonds is via theenzymatic hydrolysisof amygdalin.P450monooxygenasesare involved in the amygdalin biosynthetic pathway. A point mutation in abHLHtranscription factorpreventstranscriptionof the two cytochrome P450 genes, resulting in the sweet kernel trait.
The wordalmondis aloanwordfromOld Frenchalmandeoralemande,descended fromLate Latinamandula,amindula, modified fromClassical Latinamygdala, which is in turn borrowed fromAncient Greekamygdálē(ἀμυγδάλη)(cf.amygdala, an almond-shaped portion of the brain).LateOld Englishhadamygdales'almonds'.
The adjectiveamygdaloid(literally 'like an almond, almond-like') is used to describe objects which are roughly almond-shaped, particularly a shape which is part way between atriangleand anellipse. For example, the amygdala of the brain uses a direct borrowing of the Greek termamygdalē.
The precise origin of the almond is controversial due to estimates for its emergence across wide geographic regions.Sources indicate that its origins were in an area stretching acrossCentral Asia,Iran,Turkmenistan,Tajikistan,Kurdistan,Afghanistan, andIraq,or in aneastern Asiansubregion betweenMongoliaandUzbekistan.In other assessments, both botanical andarchaeologicalevidence indicates that almonds originated and were first cultivated inWest Asia, particularly in countries of theLevant.Other estimates specified Iran andAnatolia(present dayTurkey) as origin locations of the almond, with botanical evidence for Iran as the main origin centre.
The wild form of domesticated almond also grew in parts of the Levant.Almond cultivation was spread by humans centuries ago along the shores of theMediterranean Seainto northern Africa and southern Europe,and more recently to other world regions, notablyCalifornia.
Selection of the sweet type from the many bitter types in the wild marked the beginning of almond domestication.The wild ancestor of the almond used tobreedthe domesticated species is unknown.The speciesPrunus fenzlianamay be the most likely wild ancestor of the almond, in part because it is native toArmeniaandwestern Azerbaijan, where it was apparently domesticated.Wild almond species were grown by early farmers, "at first unintentionally in the garbage heaps, and later intentionally in their orchards".
Almonds were one of the earliest domesticatedfruit 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 ofgrafting".Domesticated almonds appear in theEarly Bronze Age(3000–2000 BC), such as the archaeological sites ofNumeira(Jordan),or possibly earlier. Another well-known archaeological example of the almond is the fruit found inTutankhamun's tomb in Egypt (c. 1325 BC), probably imported from the Levant.An article on almond tree cultivation in Spain is brought down inIbn al-'Awwam's 12th-century agricultural work,Book onAgriculture.
Of the European countries that theRoyal Botanic Garden Edinburghreported as cultivating almonds, Germanyis the northernmost, though the domesticated form can be found as far north as Iceland.
Almond trees are small to medium-sized but commercial cultivars can begraftedonto a different root-stock to produce smaller trees. Varieties include:
Breeding programmeshave found thehigh shell-seal trait.
The most widely planted varieties of almond areself-incompatible; hence these trees require pollen from a tree with different genetic characters to produce seeds. Almond orchards therefore must grow mixtures of almond varieties. In addition, the pollen is transferred from flower to flower by insects; therefore commercial growers must ensure there are enough insects to perform this task.The large scale of almond production in the U.S. creates a significant problem of providing enough pollinating insects. Additional pollinating insects are therefore brought to the trees. ThepollinationofCalifornia's almondsis the largest annualmanaged pollinationevent in the world, with over 1 million hives (nearly half of allbeehivesin the US) being brought to the almond orchards each February.
Much of the supply of bees is managed by pollination brokers, who contract with migratorybeekeepersfrom at least 49 states for the event. This business was heavily affected bycolony collapse disorderat the turn of the 21st century, causing a nationwide shortage of honey bees and increasingthe priceofinsect pollination. To partially protect almond growers from these costs, researchers at theAgricultural Research Service, part of theUnited States Department of Agriculture(USDA), developedself-pollinatingalmond trees that combine this character with quality characters such as a flavour and yield.Self-pollinating almond varieties exist, but they lack some commercial characters. However, through natural hybridisation between different almond varieties, a new variety that was self-pollinating with a high yield of commercial quality nuts was produced.
Almond trees can be attacked by an array of damaging microbes, fungal pathogens, plant viruses, and bacteria.
Pavement ants (Tetramorium caespitum), southern fire ants (Solenopsis xyloni), and thief ants (Solenopsis molesta) areseed predators.Bryobia rubrioculusmites are most known for their damage to this crop.
Almond production in California is concentrated mainly in theCentral Valley,where the mild climate, rich soil, abundant sunshine and water supply make for ideal growing conditions. Due to thepersistent droughts in Californiain the early 21st century, it became more difficult to raise almonds in a sustainable manner.The issue is complex because of the high amount of water needed to produce almonds: a single almond requires roughly 1.1 US gallons (0.92 imperial gallons; 4.2 litres) of water to grow properly.Regulations related to water supplies are changing so some growers have destroyed their current almond orchards to replace with either younger trees or a different crop such aspistachiothat needs less water.
Sustainability strategies implemented by theAlmond Board of Californiaand almond farmers include:
In 2022, world production of almonds was 3.6 milliontonnes, led by the United States (table). Secondary producers were Australia and Spain.
In the United States, production is concentrated in California where 400,000 ha (1,000,000 acres) and six different almond varieties were under cultivation in 2017, with a yield of 2.25 billion pounds (1.02 billion kilograms) of shelled almonds.California production is marked by a period of intense pollination during late winter byrentedcommercial bees transported by truck across the U.S. to almond groves, requiring more than half of the total U.S. commercial honeybee population.The value of total U.S. exports of shelled almonds in 2016 was $3.2 billion.
All commercially grown almonds sold as food in the U.S. are sweet cultivars. The U.S.Food and Drug Administrationreported in 2010 that some fractions of imported sweet almonds were contaminated with bitter almonds, which contain cyanide.
Australia is the largest almond production region in theSouthern Hemisphere. Most of the almond orchards are located along theMurray Rivercorridor inNew South Wales, Victoria, andSouth Australia.
Spain has diverse commercial cultivars of almonds grown inCatalonia,Valencia,Murcia, Andalusia, andAragónregions, and theBalearic Islands.Production in 2016 declined 2% nationally compared to 2015 production data.
The almond cultivar 'Marcona' is recognisably different from other almonds and is marketed by name.The kernel is short, round, relatively sweet, and delicate in texture. Its origin is unknown and has been grown in Spain for a long time; the tree is very productive, and the shell of the nut is hard.
Bitter almonds contain 42 times higher amounts of cyanide than the trace levels found in sweet almonds.Extract of bitter almond was once used medicinally but even in small doses, effects are severe or lethal, especially in children; the cyanide must be removed before consumption.The acute oral lethal dose of cyanide for adult humans is reported to be 0.5–3.5 mg/kg (0.2–1.6 mg/lb) of body weight (approximately 50 bitter almonds), so that for children consuming 5–10 bitter almonds may be fatal.Symptoms of eating such almonds includevertigoand other typical cyanide poisoning effects.
Almonds may causeallergyorintolerance. Cross-reactivity is common withpeachallergens(lipid transfer proteins) andtree nut allergens. Symptoms range from local signs and symptoms (e.g.,oral allergy syndrome,contact urticaria) to systemic signs and symptoms includinganaphylaxis(e.g.,urticaria,angioedema, gastrointestinal and respiratory symptoms).
Almonds are susceptible toaflatoxin-producing moulds.Aflatoxins are potentcarcinogenicchemicals produced by moulds such asAspergillus flavusandAspergillus parasiticus.The mould contamination may occur from soil, previously infested almonds, and almond pests such as navel-orange worm. High levels of mould growth typically appear as grey to black filament-like growth. It is unsafe to eat mould-infected tree nuts.
Some countries have strict limits on allowable levels of aflatoxin contamination of almonds and require adequate testing before the nuts can be marketed to their citizens. The European Union, for example, introduced a requirement since 2007 that all almond shipments to the EU be tested for aflatoxin. If aflatoxin does not meet the strict safety regulations, the entire consignment may be reprocessed to eliminate the aflatoxin or it must be destroyed.
Breeding programs have found thehigh shell-sealtrait.High shell-seal providesresistanceagainst theseAspergillusspecies and so against the development of their toxins.
After tracing cases ofsalmonellosisto almonds, the USDA approved a proposal by the Almond Board of California to pasteurise almonds sold to the public. After publishing the rule in March 2007, the almond pasteurisation program became mandatory for California companies effective 1 September 2007.Raw, untreated California almonds have not been available in the U.S. since then.
California almonds labeled "raw" must be steam-pasteurised or chemically treated withpropylene oxide(PPO). This does not apply to imported almondsor almonds sold from the grower directly to the consumer in small quantities.The treatment also is not required for raw almonds sold for export outside of North America.
The Almond Board of California states: "PPO residue dissipates after treatment". TheU.S. Environmental Protection Agencyhas reported: "Propylene oxide has been detected in fumigated food products; consumption of contaminated food is another possible route of exposure". PPO is classified asGroup 2B("possibly carcinogenic to humans").
The USDA-approved marketing order was challenged in court by organic farmers organised by theCornucopia Institute, a Wisconsin-based farm policy research group which filed a lawsuit in September 2008. According to the institute, this almond marketing order has imposed significant financial burdens on small-scale and organic growers and damaged domestic almond markets. A federal judge dismissed the lawsuit in early 2009 on procedural grounds. In August 2010, a federal appeals court ruled that the farmers have a right to appeal the USDA regulation. In March 2013, the court vacated the suit on the basis that the objections should have been raised in 2007 when the regulation was first proposed.
Almonds are 4% water, 22%carbohydrates, 21%protein, and 50% fat. In a100-gram (3+1⁄2-ounce) reference amount, almonds supply 2,420 kilojoules (579 kilocalories) offood energy. The almond is a nutritionally dense food, providing a rich source (20% or more of theDaily Value, DV) of theB vitaminsriboflavinandniacin,vitamin E, and theessential mineralscalcium, copper, iron,magnesium,manganese,phosphorus, andzinc. Almonds are a moderate source (10–19% DV) of the B vitaminsthiamine,vitamin B6, andfolate, choline, and the essential mineralpotassium. They also contain substantialdietary fibre, themonounsaturated fat,oleic acid, and thepolyunsaturated fat, linoleic acid. Typical of nuts and seeds, almonds are a source ofphytosterolssuch asbeta-sitosterol,stigmasterol,campesterol,sitostanol, andcampestanol.
Almonds are included as a good source of protein among recommended healthy foods by theU.S. Department of Agriculture(USDA).A 2016 review ofclinical researchindicated that regular consumption of almonds may reduce the risk ofheart diseaseby lowering blood levels ofLDL cholesterol.
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, slivered, and ground into flour. Almond pieces around2–3 millimetres (1⁄16–1⁄8in) in size, called "nibs", are used for special purposes such as decoration.
Almonds are a common addition to breakfastmueslior oatmeal.Colomba di Pasquais the Easter counterpart of the two well-knownItalianChristmasdesserts,panettoneandpandoro
A wide range of classic sweets feature almonds as a central ingredient. Marzipan was developed in the Middle Ages. Since the 19th century almonds have been used to make bread,almond butter, cakes and puddings, candied confections, almond cream-filled pastries,nougat, cookies (macaroons,biscottiandqurabiya), and cakes (financiers,Esterházy torte), and other sweets and desserts.
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. Also in the Middle East they are often eaten with dates. They are available only from mid-April to mid-June in the Northern Hemisphere; pickling or brining extends the fruit's shelf life.
Marzipan, a smooth, sweetenedalmond paste, is used in a number of elegant cakes and desserts.Princess cakeis covered by marzipan (similar tofondant), as isBattenberg cake. InSicily, sponge cake is covered with marzipan to makecassatella di sant'Agataandcassata siciliana, and marzipan is dyed and crafted into realistic fruit shapes to makefrutta martorana. TheAndalusianChristmas pastrypan de Cádizis filled with marzipan and candied fruit.
Almonds can be processed into amilk substitutecalled 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 forlactose intolerantpeople andvegans. Raw, blanched, and lightly toasted almonds work well for different production techniques, some of which are similar to that ofsoy milkand some of which use no heat, resulting inraw milk.
Almond milk, along with almond butter and almond oil, are versatile products used in both sweet and savoury dishes.
InMoroccan cuisine, sharbat billooz, a common beverage, is made by blending blanched almonds with milk, sugar and other flavourings.
Almond flouror groundalmond mealcombined with sugar or honey as marzipan is often used as agluten-freealternative to wheat flour in cooking and baking.
Almonds contain polyphenols in theirskinsconsisting offlavonols,flavan-3-ols,hydroxybenzoic acidsandflavanonesanalogous to those of certain fruits and vegetables. These phenolic compounds and almond skinprebioticdietary fibre have commercial interest asfood additivesordietary supplements.
Historically, almond syrup was anemulsionof sweet and bitter almonds, usually made withbarley syrup(orgeat syrup) or in a syrup oforange flower waterand sugar, often flavoured with a synthetic aroma of almonds.Orgeat syrup is an important ingredient in theMai Taiand many otherTiki drinks.
Due to the cyanide found in bitter almonds, modern syrups generally are produced only from sweet almonds. Such syrup products do not contain significant levels ofhydrocyanic acid, so are generally considered safe for human consumption.
Almonds are a rich source of oil, with 50% of kernel dry mass as fat (whole almond nutrition table). In relation to total dry mass of the kernel, almond oil contains 32%monounsaturatedoleic acid (anomega-9 fatty acid), 13%linoleic acid(apolyunsaturatedomega-6essential fatty acid), and 10%saturated fatty acid(mainly aspalmitic acid). Linolenic acid, a polyunsaturatedomega-3fat, is not present (table). Almond oil is a rich source of vitamin E, providing 261% of the Daily Value per 100 millilitres.
When almond oil is analyzed separately and expressed per 100 grams as a reference mass, the oil provides 3,700 kJ (884 kcal) of food energy, 8 grams of saturated fat (81% of which is palmitic acid), 70 grams of oleic acid, and 17 grams of linoleic acid (oil table).
Oleum amygdalae, the fixed oil, is prepared from either sweet or bitter almonds, and is a glyceryl oleate with a slight odour and a nutty taste. It is almost insoluble inalcoholbut readily soluble inchloroformorether. Almond oil is obtained from the driedkernelof almonds.Sweet almond oil is used as a carrier oil in aromatherapy and cosmetics while bitter almond oil, containing benzaldehyde, is used as a food flavouring and in perfume.
The almond is highly revered in some cultures. The tree originated in the Middle East. In the Bible, the almond is mentioned ten times, beginning withGenesis43:11, where it is described as "among the best of fruits". InNumbers17,Leviis chosen from the other tribes of Israel byAaron's rod, which brought forth almond flowers. The almond blossom supplied a model for themenorahwhich stood in theHoly 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" (Exodus25:33–34; 37:19–20). ManySephardic Jewsgive five almonds to each guest before special occasions like weddings.
Similarly,Christian symbolismoften uses almond branches as a symbol of thevirgin birth of Jesus; paintings andiconsoften includealmond-shaped haloesencircling theChrist Childand as a symbol ofMary. The word "luz", which appears in Genesis 30:37, sometimes translated as "hazel", may actually be derived from theAramaicname for almond (Luz), and is translated as such in theNew International Versionand other versions of the Bible.The Arabic name for almond is لوز "lauz" or "lūz". In some parts of the Levant and North Africa, it is pronounced "loz", which is very close to its Aramaic origin.
TheEntrance of the flower(La entrada de la flor) is an event celebrated on 1 February inTorrent, Spain, in which the clavarios and members of the Confrerie of the Mother of God deliver a branch of the first-blooming almond-tree to the Virgin.