Pine nuts are the edible seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s of pine

Pine

Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...

s (family Pinaceae

Pinaceae

Pinaceae are trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae are supported as monophyletic by its protein-type sieve...

, genus Pinus). About 20 species of pine produce seeds large enough to be worth harvesting; in other pines the seeds are also edible, but are too small to be of great value as a human food.

Species and geographic spread

In Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, two species are widely harvested, Korean Pine

Korean Pine

The tree species Pinus koraiensis is commonly called Korean Pine. It is native to eastern Asia, Korea, Manchuria, far eastern Russia, and central Japan. In the north of its range, it grows at moderate altitudes, typically to , whereas further south, it is a mountain tree, growing at to altitude...

 (Pinus koraiensis) in northeast Asia (the most important species in international trade), and Chilgoza Pine

Chilgoza Pine

Pinus gerardiana, known as the Chilgoza Pine, 'noosa', or 'neoza', is a pine native to the northwestern Himalaya in eastern Afghanistan, Pakistan, and northwest India, growing at elevations between 1800–3350 m...

 (Pinus gerardiana) in the western Himalaya. Four other species, Siberian Pine

Siberian Pine

The Siberian Pine, Pinus sibirica, in the family Pinaceae is a species of pine tree that occurs in Siberia from 58°E in the Ural Mountains east to 126°E in the Stanovoy Range in southern Sakha Republic, and from Igarka at 68°N in the lower Yenisei valley, south to 45°N in central...

 (Pinus sibirica), Siberian Dwarf Pine

Siberian Dwarf Pine

Pinus pumila is a native to northeastern Asia, including the islands of Japan. This shrubby pine ranges from 1–3 m in height, exceptionally up to 5 m, but may have individual branches that extend farther along the ground in length...

 (Pinus pumila), Chinese White Pine

Chinese White Pine

The Chinese White Pine is a species of pine native to China, occurring from southern Shanxi west to southern Gansu and south to Yunnan, with outlying populations in Anhui and Taiwan; it also extends a short distance into northern Myanmar. It grows at 1,000-3,300 m altitude, with the lower...

 (Pinus armandii) and Lacebark Pine (Pinus bungeana), are also used to a lesser extent. Afghanistan

Afghanistan

Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...

 is an important source of pine nuts.

Pine nuts produced in Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 mostly come from the Stone Pine

Stone Pine

The Stone Pine , is also called Italian Stone Pine, or Umbrella Pine , and Parasol Pine. It is in the pine family Pinaceae and occasionally listed under the invalid name Pinus sativa. The tree is native to the Mediterranean region...

 (Pinus pinea), which has been cultivated for its nuts for over 6,000 years, and harvested from wild trees for far longer. The Swiss Pine

Swiss Pine

The Swiss Pine or Arolla Pine, Pinus cembra, is a species of pine tree that occurs in the Alps and Carpathian Mountains of central Europe, in Poland , Switzerland, France, Italy, Austria, Germany, Slovenia, Slovakia, Ukraine and Romania. It typically grows at to altitude. It often reaches the...

 (Pinus cembra) is also used to a very small extent.

In North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, the main species are three of the pinyon pine

Pinyon pine

The pinyon pine group grows in the southwestern United States and in Mexico. The trees yield edible pinyon nuts, which were a staple of the Native Americans, and are still widely eaten...

s, Colorado Pinyon

Colorado Pinyon

The Colorado Pinyon, Two-needle Pinyon, or Piñon Pine, ', is a pine in the pinyon pine group whose ancestor was a member of the Madro-Tertiary Flora and is native to the United States....

 (Pinus edulis), Single-leaf Pinyon

Single-leaf Pinyon

The Single-leaf Pinyon, ', is a pine in the pinyon pine group, native to the United States and northwest Mexico. The range is in southernmost Idaho, western Utah, Arizona, southwest New Mexico, Nevada, eastern and southern California and northern Baja California.It occurs at moderate altitudes from...

 (Pinus monophylla), and Mexican Pinyon

Mexican Pinyon

The Mexican Pinyon ' is a pine in the pinyon pine group, native to western North America.-Distribution:The range extends from westernmost Texas, United States , south through much of Mexico, occurring widely along the Sierra Madre Oriental and Sierra Madre Occidental ranges, and more rarely in the...

 (Pinus cembroides). The other eight pinyon species are used to a small extent, as are Gray Pine

Gray Pine

Pinus sabiniana , with the common names gray pine, California foothill pine, and the more historically and internationally used digger pine, is a pine endemic to California in the United States...

 (Pinus sabineana), Torrey Pine

Torrey Pine

The Torrey Pine, Pinus torreyana, is the rarest pine species in the United States, an endangered species growing only in San Diego County and on one of the Channel Islands, endemic to the coastal sage and chaparral ecoregion in the U.S...

 (Pinus torreyana), Sugar Pine

Sugar Pine

Pinus lambertiana, commonly known as the sugar pine or sugar cone pine, is the tallest and most massive pine, with the longest cones of any conifer...

 (Pinus lambertiana) and Parry Pinyon

Parry Pinyon

Pinus quadrifolia, the Parry Pinyon, is a pine in the pinyon pine group, native to southernmost California in the United States and northern Baja California in Mexico, from 33° 30' N south to 30° 30' N. It occurs at moderate altitudes from to , rarely as low as and as high as...

 (Pinus quadrifolia).

In the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, pine nuts are mainly harvested by American Indian

Indigenous peoples of the Americas

The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...

s, particularly the Uto-Aztecan: Shoshone

Shoshone

The Shoshone or Shoshoni are a Native American tribe in the United States with three large divisions: the Northern, the Western and the Eastern....

, Paiute

Paiute

Paiute refers to three closely related groups of Native Americans — the Northern Paiute of California, Idaho, Nevada and Oregon; the Owens Valley Paiute of California and Nevada; and the Southern Paiute of Arizona, southeastern California and Nevada, and Utah.-Origin of name:The origin of...

 and Hopi

Hopi

The Hopi are a federally recognized tribe of indigenous Native American people, who primarily live on the Hopi Reservation in northeastern Arizona. The Hopi area according to the 2000 census has a population of 6,946 people. Their Hopi language is one of the 30 of the Uto-Aztecan language...

, and Washoe tribes. Certain treaties negotiated by tribes and laws in Nevada

Nevada

Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...

 guarantee Native Americans' right to harvest pine nuts.

Pollination and seed development

The pinyon pine nut (seed) species will take 18 months to complete its maturity; however, to reach full maturity, the environmental conditions must be favorable for the tree and its cone.

Development begins in early spring with pollination. A tiny cone, about the size of a small marble, will form from mid-spring to the end of summer; the premature cone will then become and remain dormant (with a cessation of growth) until the following spring. The cone will then commence growth until it reaches maturity near the end of summer. The mature pinyon pine cone is ready to harvest ten days before the green cone begins to open. A cone is harvested by placing it in a burlap bag and exposing it to a heat source such as the sun to begin the drying process. It takes about 20 days until the cone fully opens. Once it is fully open and dry, the seed can be easily extracted in various ways. The most common and practical extracting method used is the repeated striking of the burlap bag containing the cone(s) against a rough surface to cause the cone(s) to shatter, leaving just the job of separating by hand the seed from the residue within the bag.

Another option for harvesting is to wait until the cone opens on the tree (as it naturally will) and harvest the cone from the pinyon pine, followed by the extracting process mentioned above. Fallen seed can also be gathered beneath the trees.

Ecology and status

In the United States, millions of hectares of productive pinyon pine woods have been destroyed due to conversion of lands, and in China, destructive harvesting techniques (such as breaking off whole branches to harvest the cones) and the removal of trees for timber

Timber

Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...

 have led to losses in production capacity.

Elevation and pinecone production

The elevation of the pinyon pine is an important determinant of the quantity of pine cone production, and therefore, will largely determine the amount of pine nuts the tree will yield.

Pinyon pine cone production is most commonly found at an elevation between 6000 feet (1,828.8 m) and 8500 feet (2,590.8 m), and ideally at 7000 feet (2,133.6 m). This is due to increased temperatures at elevations lower than 6000 feet (1,828.8 m) during the spring, will dry up humidity and moisture contents (particularly snow packs) that provide for the tree throughout the spring and summer, causing little nourishment for pine cone maturity. Although there are several other environmental factors, such as clouds and rain, that determine the conditions of the ecology, without this nourishment (water), the cones are more susceptible to perishing and the tree will tend to abort cones.

There are certain topographical areas found in lower elevations, such as shaded canyons, where the humidity remains constant throughout the spring and summer, allowing the pine cones to fully mature and produce seed.

At elevations above 8500 feet (2,590.8 m), the temperature will substantially drop, drastically affecting the state of the dormant cone. During the winter, the change in temperature, along with gusty winds, with their severity, can cause the cones to be susceptible to freezing that damages them permanently, in which case, growth is stunted and they wither away.

Physical characteristics

Pine nuts contain, depending on species, 10–34% protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

, with Stone Pine having the highest content. They are also a source of dietary fiber

Dietary fiber

Dietary fiber, dietary fibre, or sometimes roughage is the indigestible portion of plant foods having two main components:* soluble fiber that is readily fermented in the colon into gases and physiologically active byproducts, and* insoluble fiber that is metabolically inert, absorbing water as it...

. When first extracted from the pine cone

Conifer cone

A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...

, they are covered with a hard shell (seed coat), thin in some species, thick in others. The nutrition is stored in the embryo (sporophyte

Sporophyte

All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...

) in the centre. Although a nut

Nut (fruit)

A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...

 in the culinary sense, in the botanical

Botany

Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...

 sense pine nuts are seeds; being a gymnosperm

Gymnosperm

The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

, they lack a carpel (fruit) outside.

The shell must be removed before the pine nut can be eaten. Unshelled pine nuts have a long shelf life if kept dry and refrigerated (-5 C to 2 °C (35.6 °F)); shelled nuts (and unshelled nuts in warm conditions) deteriorate rapidly, becoming rancid

Rancidification

Rancidification is the chemical decomposition of fats, oils and other lipids . When these processes occur in food, undesirable odors and flavors can result. In some cases, however, the flavors can be desirable . In processed meats, these flavors are collectively known as "warmed over flavor"...

 within a few weeks or even days in warm humid conditions. Pine nuts are commercially available in shelled form, but due to poor storage, can have poor flavour and may be already rancid at the time of purchase. Consequently, pine nuts are often frozen

Frozen food

Freezing food preserves it from the time it is prepared to the time it is eaten. Since early times, farmers, fishermen, and trappers have preserved their game and produce in unheated buildings during the winter season. Freezing food slows down decomposition by turning water to ice, making it...

 to preserve their flavour.
European pine nuts may be distinguished from Asian ones by their greater length in comparison to girth; Asian pine nuts are stubbier, shaped somewhat like long kernels of corn. The American pinyon nuts are known for their large size and ease of shelling. In the United States, P. edulis, the hard shell or New Mexico and Colorado, became a sought-after species due to the Trading Post System and the Navajo people who used the nuts as a means of commerce. The Italian pine nut, (P. pinea) was brought to the United States by immigrants, and became a favored treat along the East Coast until the early 1930s, when bumper crops of American pine nuts were readily available at low prices.

Culinary uses

Pine nuts have been eaten in Europe and Asia since the Paleolithic

Paleolithic

The Paleolithic Age, Era or Period, is a prehistoric period of human history distinguished by the development of the most primitive stone tools discovered , and covers roughly 99% of human technological prehistory...

 period. They are frequently added to meat

Meat

Meat is animal flesh that is used as food. Most often, this means the skeletal muscle and associated fat and other tissues, but it may also describe other edible tissues such as organs and offal...

, fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

, salads and vegetable

Vegetable

The noun vegetable usually means an edible plant or part of a plant other than a sweet fruit or seed. This typically means the leaf, stem, or root of a plant....

 dishes

Recipe

A recipe is a set of instructions that describe how to prepare or make something, especially a culinary dish.-Components:Modern culinary recipes normally consist of several components*The name of the dish...

 or baked into bread

Bread

Bread is a staple food prepared by cooking a dough of flour and water and often additional ingredients. Doughs are usually baked, but in some cuisines breads are steamed , fried , or baked on an unoiled frying pan . It may be leavened or unleavened...

. In Italian

Italian language

Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...

 they are called pinoli (in the U.S. they are often called "pignoli" but in Italy "pignolo" is actually a word far more commonly used to describe a fussy, overly fastidious or extremely meticulous person) and are an essential component of Italian pesto

Pesto

Pesto is a sauce originating in Genoa in the Liguria region of northern Italy , and traditionally consists of crushed garlic, basil and pine nuts blended with olive oil and Parmigiano Reggiano and Fiore Sardo...

 sauce. Pignoli cookies, an Italian American specialty confection (in Italy these would be called "biscotti ai pinoli"), are made of almond

Almond

The almond , 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...

 flour formed into a dough similar to that of a macaroon

Macaroon

A macaroon is a type of light, baked confection, described as either small cakes or meringue-like cookies depending on their consistency. The original macaroon was a "small sweet cake consisting largely of ground almonds" similar to Italian or Moroccan amaretti.The English word macaroon and French...

 and then topped with pine nuts. In Spain, a sweet is made of small marzipan balls covered with pine nuts, painted with egg and lightly cooked. Pine nuts are also featured in the salade landaise of southwestern France. Pine nut coffee, known as piñón (Spanish

Spanish language

Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...

 for pine nut), is a speciality found in the southwest United States, especially New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

, and is typically a dark roast coffee having a deep, nutty flavour; roasted and lightly salted pine nuts can often be found sold on the side of the road in cities across New Mexico to be used for this purpose, as well as a snack. The Nevada, or Great Basin, pine nut has a sweet fruity flavor and is relished for its large size, sweet flavor and ease of peeling. Pine nuts are also widely used in Middle Eastern cuisine, reflected in a diverse range of dishes such as kibbeh

Kibbeh

Kibbeh or kibbe is an Arab dish made of bulgur or rice and chopped meat. The best-known variety is a torpedo-shaped fried croquette stuffed with minced beef or lamb. Other types of kibbeh may be shaped into balls or patties, and baked or cooked in broth.Kibbeh is a popular dish in Levantine...

, sambusek, desserts such as baklava

Baklava

Baklava is a rich, sweet pastry made of layers of filo pastry filled with chopped nuts and sweetened with syrup or honey. It is characteristic of the cuisines of the former Ottoman Empire and much of central and southwest Asia....

, and many others.

Throughout Europe and Middle East the pine nuts used are from Pinus pinea (Stone Pine). They are easily distinguished from the Asian pine nuts by their more slender shape and more homogeneous flesh. Due to the lower price, Asian pine nuts are also often used, especially in cheaper preparations. Pine nuts contain thiamine (vitamin B₁) and protein.

Risks of eating pine nuts

A small minority of pine nuts cultivated in China can cause taste disturbance

Dysgeusia

Dysgeusia is the distortion of the sense of taste. Dysgeusia is also often associated with ageusia, which is the complete lack of taste, and hypogeusia, which is the decrease in taste sensitivity. An alteration in taste or smell may be a secondary process in various disease states, or it may be...

s, lasting between a few days to a few weeks after consumption. A bitter, metallic taste is described. Though unpleasant, there are no lasting effects. This phenomenon was first described in a scientific paper in 2001. Some publications have made reference to this phenomenon as "pine mouth".
The Nestlé Research Centre has hypothesized that a particular species of Chinese pine nuts, Pinus armandii, is the cause of the problem. The suspect species of pine nuts are smaller, duller, and more rounded than typical pine nuts. This finding has recently been confirmed.
Metallic taste disturbance, known as metallogeusia, is typically reported 1–3 days after ingestion, being worse on day 2 and lasting typically up to 2 weeks. Cases are self-limited and resolve without treatment.
Möller has postulated a hypothesis that could explain why the bitter taste appears several days after ingestion and lasts for as long. A well known physiological process known as enterohepatic recirculation (EHR)

Enterohepatic circulation

Enterohepatic circulation refers to the circulation of biliary acids from the liver, where they are produced and secreted in the bile, to the small intestine, where it aids in digestion of fats and other substances, back to the liver....

 could play a key role in the development of PNS.

The FDA

Food and Drug Administration

The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...

 is currently investigating “Pine Mouth”.

Nutritional information

100g of dried pine nuts contains:

• Calories :673
• Carbohydrates(g): 13.08
• Fibers(g): 3.7
• Protein(g): 13.69
• Cholesterol(mg): 0

Pine nut oil

Pine nuts can be pressed to extract pine nut oil, which is valued for its mild, nutty flavour.
One study indicates Korean pine nut oil may suppress appetite.

Other similar seeds

The large edible seeds of species of the Southern Hemisphere

Southern Hemisphere

The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

 conifer

Pinophyta

The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...

 genus Araucaria

Araucaria

Araucaria is a genus of evergreen coniferous trees in the family Araucariaceae. There are 19 extant species in the genus, with a highly disjunct distribution in New Caledonia , Norfolk Island, eastern Australia, New Guinea, Argentina, Chile, and southern Brazil.-Description:Araucaria are mainly...

, notably Araucaria araucana

Araucaria araucana

Araucaria araucana is an evergreen tree growing to tall with a trunk diameter. The tree is native to central and southern Chile, western Argentina and south Brazil. Araucaria araucana is the hardiest species in the conifer genus Araucaria...

(Pehuén) of Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

, Araucaria bidwillii

Araucaria bidwillii

Araucaria bidwillii, the Bunya Pine, is a large evergreen coniferous tree in the genus Araucaria, family Araucariaceae. It is native to south-east Queensland with two small disjunct populations in northern Queensland's World Heritage listed Wet Tropics, and many fine old specimens planted in New...

(Bunya) of Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and Araucaria angustifolia

Araucaria angustifolia

Araucaria angustifolia, the Paraná pine or Brazilian pine , is a species in the conifer genus Araucaria. Covering an original area of 233000 km², it is native to southern Brazil Araucaria angustifolia, the Paraná pine or Brazilian pine , is a species in the conifer genus Araucaria. Covering an...

(Parana pine) of Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, are also often called, although improperly, pine nuts. In South America, Araucaria seeds are called piñas, pinhas or pinhões.