| Pistacia vera | |
|---|---|
| Pistacia vera Kerman fruits ripening | |
| Roasted pistachio nut with shell | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Sapindales |
| Family: | Anacardiaceae |
| Genus: | Pistacia |
| Species: | P. vera |
| Binomial name | |
| Pistacia vera L. |
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The pistachio, Pistacia vera in the Anacardiaceae family, is a small tree originally from Persia (Iran), which now can also be found in regions of Syria, Lebanon, Turkey, Greece, Kyrgyzstan, Turkmenistan, India, Pakistan, Egypt, Sicily and possibly Afghanistan (especially in the provinces of Samangan and Badghis), as well as in the United States, specifically California. The tree produces an important culinary nut.
Pistacia vera often is confused with other species in the genus Pistacia that are also known as pistachio. These species can be distinguished from P. vera by their geographic distributions (in the wild) and their nuts. Their nuts are much smaller, have a strong flavor of turpentine, and have a shell that is not hard.
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Pistachios have been a part of the human diet at least since the late Paleolithic. The modern pistachio nut P. vera was first cultivated in Western Asia, where it has long been an important crop in cooler parts of Iran. It appears in Dioscurides as pistakia πιστάκια, recognizable as P. vera by its comparison to pine nuts.[1] Its cultivation spread into the Mediterranean world by way of Iran from Syria: Pliny in his Natural History asserts that pistacia, "well known among us," was one of the trees unique to Syria, and in another place, that the nut was introduced into Italy by the Roman consul in Syria, Lucius Vitellius the Elder (consul in Syria in 35 CE) and into Hispania at the same time by Flaccus Pompeius.[2] The early sixth-century manuscript De observatione ciborum (On the observance of foods) by Anthimus implies that pistacia remained well known in Europe in Late Antiquity. The pistachio is one of two nuts mentioned in the Bible. The pistachio is mentioned only once,[3] although the almond is mentioned many times.
More recently, the pistachio has been cultivated commercially in the English-speaking world, in Australia, New Mexico,[4] and in California, where it was introduced in 1854 as a garden tree.[5] David Fairchild of the United States Department of Agriculture introduced hardier cultivars collected in China to California in 1904 and 1905, but it was not promoted as a commercial crop until 1929.[4][6] Walter T. Swingle's pistachios from Syria had already fruited well at Niles by 1917.[7]
The earliest records of pistachio in English are around roughly year 1400, with the spellings "pistace" and "pistacia". The word pistachio comes from medieval Italian pistacchio, which is from classical Latin pistacium, which is from ancient Greek pistákion and pistákē, which is generally believed to be from Middle Persian, although unattested in Middle Persian. Later in Persian, the word is attested in Persian as pista. As mentioned, the tree came to the ancient Greeks from Western Asia.[8]
Pistachio is a desert plant, and is highly tolerant of saline soil. It has been reported to grow well when irrigated with water having 3,000–4,000 ppm of soluble salts.[4] Pistachio trees are fairly hardy in the right conditions, and can survive temperatures ranging between −10°C (14°F) in winter and 40°C (104°F) in summer. They need a sunny position and well-drained soil. Pistachio trees do poorly in conditions of high humidity, and are susceptible to root rot in winter if they get too much water and the soil is not sufficiently free-draining. Long, hot summers are required for proper ripening of the fruit.
The Jylgyndy Forest Reserve, a preserve protecting the native habitat of Pistacia vera groves, is located in the Nooken District of Jalal-Abad Province of Kyrgyzstan.
The bush grows up to 10 metres (33 ft) tall. It has deciduous pinnate leaves 10–20 centimeters (4–8 inches) long. The plants are dioecious, with separate male and female trees. The flowers are apetalous and unisexual, and borne in panicles.
The fruit is a drupe, containing an elongated seed, which is the edible portion. The seed, commonly thought of as a nut, is a culinary nut, not a botanical nut. The fruit has a hard, whitish exterior shell. The seed has a mauvish skin and light green flesh, with a distinctive flavor. When the fruit ripens, the shell changes from green to an autumnal yellow/red, and abruptly splits part way open (see photo). This is known as dehiscence, and happens with an audible pop. The splitting open is a trait that has been selected by humans.[9] Commercial cultivars vary in how consistently they split open.
Each pistachio tree averages around 50 kg of seeds, or around 50,000, every two years.[10]
The shell of the pistachio is naturally a beige color, but it is sometimes dyed red or green in commercial pistachios. Originally, dye was applied by importers to hide stains on the shells caused when the nuts were picked by hand. Most pistachios are now picked by machine and the shells remain unstained, making dyeing unnecessary except to meet ingrained consumer expectations. Roasted pistachio nuts can be artificially turned red if they are marinated prior to roasting in a salt and strawberry marinade, or salt and citrus salts.
Like other members of the Anacardiaceae family (which includes poison ivy, sumac, mango, and cashew), pistachios contain urushiol, an irritant that can cause allergic reactions.[11]
The trees are planted in orchards, and take approximately seven to ten years to reach significant production. Production is alternate bearing or biennial bearing, meaning the harvest is heavier in alternate years. Peak production is reached at approximately 20 years. Trees are usually pruned to size to make the harvest easier. One male tree produces enough pollen for eight to twelve nut-bearing females. Harvesting in the United States and in Greece is often accomplished by using shaking equipment to shake the nuts off the tree. After hulling and drying, pistachios are sorted according to open mouth and closed mouth shell. Sun drying has been found to be the best method of drying.[12] Then they are roasted or processed by special machines to produce pistachio kernels.
Pistachio trees are vulnerable to a wide variety of diseases (see List of pistachio diseases). Among these is infection by the fungus Botryosphaeria, which causes panicle and shoot blight (i.e., kills flowers and young shoots), and can damage entire pistachio orchards.
In California, almost all female pistachio trees are the cultivar "Kerman". A sprig from a mature female Kerman is grafted onto a one-year-old rootstock. Male pistachios may be a different variety.
In Greece, the cultivated type of pistachios is different. It has an almost-white shell, an excellent, sweet taste, a red-green kernel and a little bit more close mouth shell than "Kerman" variety. Most of the production in Greece comes from the region of Almyros.
Bulk container shipments of pistachio nuts are prone to self-heating and spontaneous combustion because of their high fat and low water content.[13]
| Pistachio production (tonnes)[14] | ||||
|---|---|---|---|---|
| Country | 2005 | 2006 | 2007 | 2008 |
| Iran | 229 657 | 250 000 | 315 500 | 192 269 |
| United States | 128 367 | 107 955 | 188 696 | 126 100 |
| Turkey | 60 000 | 110 000 | 73 416 | 120 113 |
| Syria | 44 642 | 73 183 | 52 066 | 52 600 |
| China | 34 000 | 36 000 | 38 000 | 40 000 |
| Greece | 8 847 | 8 233 | 8 148 | 8 100 |
| Afghanistan | 2 457 | 2 457 | 3 600 | 2 500 |
| Tunisia | 2 000 | 2 700 | 2 500 | 2 500 |
| Italy | 2 719 | 1 024 | 2 782 | 2 000 |
| Kyrgyzstan | 300 | 500 | 800 | 800 |
| Pakistan | 597 | 632 | 536 | 773 |
| Madagascar | 210 | 220 | 230 | 230 |
| Uzbekistan | 300 | 203 | 200 | 200 |
| Côte d'Ivoire | 100 | 100 | 100 | 100 |
| Morocco | 50 | 50 | 50 | 50 |
| Cyprus | 15 | 12 | 25 | 24 |
| Mexico | 26 | 4 | 10 | 10 |
| Mauritius | 5 | 5 | 5 | 5 |
| Azerbaijan | 11 | 15 | 3 | 3 |
The kernels are often eaten whole, either fresh or roasted and salted, and are also used in ice cream, pistachio butter,[15][16] pistachio paste[17] and confections such as baklava, pistachio chocolate,[18] pistachio halva[19] or biscotti and cold cuts such as mortadella. Americans make pistachio salad, which includes fresh pistachios or pistachio pudding, whipped cream, canned fruit and sometimes cottage cheese.[20] In July 2003, the Food and Drug Administration (FDA) approved the first qualified health claim specific to nuts lowering the risk of heart disease: "Scientific evidence suggests but does not prove that eating 1.5 ounces (42.5g) per day of most nuts, such as pistachios, as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease".[21]
China is the top pistachio consumer worldwide with annual consumption of 80,000 tons, while the United States consumes 45,000 tons. Russia (with consumption of 15,000 tons) and India (with consumption of 10,000 tons) are in the third and fourth places.[22]
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 2,391 kJ (571 kcal) |
| Carbohydrates | 27.65 g |
| - Sugars | 7.81 g |
| - Dietary fiber | 10.3 g |
| Fat | 45.97 g |
| Protein | 21.35 g |
| - lutein and zeaxanthin | 1205 μg |
| Thiamine (vit. B1) | 0.84 mg (73%) |
| Riboflavin (vit. B2) | 0.158 mg (13%) |
| Niacin (vit. B3) | 1.425 mg (10%) |
| Pantothenic acid (B5) | 0.513 mg (10%) |
| Vitamin B6 | 1.274 mg (98%) |
| Folate (vit. B9) | 50 μg (13%) |
| Vitamin C | 2.3 mg (3%) |
| Calcium | 110 mg (11%) |
| Iron | 4.2 mg (32%) |
| Magnesium | 120 mg (34%) |
| Phosphorus | 485 mg (69%) |
| Potassium | 1042 mg (22%) |
| Zinc | 2.3 mg (24%) |
| Manganese 1.275 mg (64%) | |
| Percentages are relative to US recommendations for adults. Source: USDA Nutrient Database |
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In research at Pennsylvania State University, pistachios in particular significantly reduced levels of low-density lipoprotein (LDL cholesterol) while increasing antioxidant levels in the serum of volunteers.[23][24][25][26] In rats, consumption of pistachios as 20% of daily caloric intake increased beneficial high-density lipoprotein (HDL cholesterol) without lowering LDL cholesterol, and while reducing LDL oxidation.[27]
Consuming unsalted, dry roasted pistachios prevents any addition of unwanted fats and additional sodium in the diet that may affect cardiac health adversely and increase hypertension.
Human studies have shown that 32-63 grams per day of pistachio nut can significantly elevate plasma levels of lutein, alpha-carotene, beta-carotene, and gamma-tocopherol.[26]
In December 2008, Dr. James Painter, a behavioral eating expert, professor and chair of School of Family and Consumer Sciences at Eastern Illinois University, described the Pistachio Principle. The Pistachio Principle describes methods of "fooling" one's body into eating less. One example used is that the act of shelling and eating pistachios one by one slows one's consumption, allowing one to feel full faster after having eaten less.[28]
The empty pistachio shells are useful for recycling in several ways. If unsalted, the shells need not be washed and dried before reuse, but washing is simple if that is not the case. Practical uses include as a fire starter just as kindling would be used with crumpled paper; to line the bottom of pots containing houseplants for drainage and retention of soil for up to two years; as a mulch for shrubs and plants that require acid soils; as a medium for orchids; and as an addition to a compost pile designed for wood items that take longer to decompose than leafy materials, taking up to a year for pistachio shells to decompose unless soil is added to the mix. Many craft uses for the shells include, holiday tree ornaments, jewelry, mosaics, and rattles.[2] Scientific research indicates that pistachio shells may be helpful in cleaning up pollution created by mercury emissions.[3]
Chisholm, Hugh, ed (1911). "Pistachio Nut". Encyclopædia Britannica (11th ed.). Cambridge University Press.