Almond

The almond (Prunus dulcis, syn. Prunus amygdalus Batsch., Amygdalus communis L., Amygdalus dulcis Mill.), is a species of tree native to the Middle East. 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, which consists 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.

Description

The almond is a small deciduous tree, growing to between 4 and 10 meters in height, with a trunk of up to 30 centimetres 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, with a serrated margin and a 2.5 cm (1 in) petiole. The flowers are white or pale pink, 3–5 cm diameter with five petals, produced singly or in pairs before the leaves in early spring.

Almond trees become productive and begin bearing fruit after five years. The fruit is mature in the autumn, 7–8 months after flowering.

In botanical terms, the almond fruit is not a nut, but a drupe 3.5–6 cm 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.

Origin and history

The almond is a native to the Mediterranean climate region of the Middle East, eastward as far as the Indus. 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.
A grove of almond trees in southern California

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."

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". 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". 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. The domesticated form can be found as far north as Iceland although the official[clarification needed] distribution of the plant in Europe shows the most northerly country to be Germany.





Oils

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).

"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.

Nutrition and health

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 or for patients suffering from diabetes mellitus or any other form of glycosuria. Almond flour is gluten-free and therefore a popular ingredient in cookery in place of wheat flour for gluten-sensitive people and people with wheat allergies and coeliac disease. A standard serving of almond flour, 1 cup, contains 20 grams of carbohydrates, of which 10 g is dietary fibre, 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 24 mg per 100 g. They are also rich in monounsaturated fat, one of the two "good" fats responsible for lowering LDL cholesterol.

Claimed health benefits of almonds include improved complexion, improved movement of food through the colon (feces) and the prevention of cancer. Recent research associates the inclusion of almonds in the diet with elevating the blood levels of high density lipoproteins and of lowering the levels of low density lipoproteins.

A controlled trial showed that 73g of almonds in the daily diet reduced LDL cholesterol by as much as 9.4%, reduced the LDL:HDL ratio by 12.0%, and increased HDL-cholesterol (i.e., the good cholesterol) by 4.6%.

In Ayurveda, an ancient system of health care that is native to the Indian subcontinent, almond is considered a nutritive for the brain and nervous system. It is said to induce high intellectual level and longevity. Almond oil is called Roghan Badam in Tibb Yunani طب يوناني (the Greco-Persian system of medicine). It is extracted by cold process, and is considered a nutritive aphrodisiac both for massage and internal consumption. Recent studies have shown that the constituents of almond have anti-inflammatory, immunity boosting, and anti-hepatotoxicity effects.

In a study printed in the Journal of Agriculture and Food Chemistry, experts discovered that almonds contain phenolics and flavonoids (a combination of flavonols, flavan-3-ols, hydroxybenzoic acids and flavanones) in their skins analogous to those of certain fruits and vegetables. For instance, a one-ounce helping of almonds holds a similar quantity of total polyphenol as ½ cup of cooked broccoli.

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).


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