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  • Blueberries 

    Blueberries are a widely distributed and widespread group of perennial flowering plants with blue or purple berries. They are classified in the section Cyanococcus with the genus Vaccinium.[1] Commercial blueberries—both wild (lowbush) and cultivated (highbush)—are all native to North America. The highbush varieties were introduced into Europe during the 1930s.[2]

    Blueberries are usually prostrate shrubs that can vary in size from 10 centimeters (4 inches) to 4 meters (13 feet) in height. In the commercial production of blueberries, the species with small, pea-size berries growing on low-level bushes are known as “lowbush blueberries” (synonymous with “wild”), while the species with larger berries growing on taller, cultivated bushes are known as “highbush blueberries”. Canada is the leading producer of lowbush blueberries, while the United States produces some 40% of the world’s supply of highbush blueberries.

    Description

    [edit]

    Many species of blueberries grow wild in North America, including Vaccinium myrtilloidesV. angustifolium and V. corymbosum, which grow on forest floors or near swamps.[3]

    Wild blueberries reproduce by cross pollination, with each seed producing a plant with a different genetic composition, causing within the same species differences in growth, productivity, color, leaf characteristics, disease resistance, flavor, and other fruit characteristics.[3] The mother plant develops underground stems called rhizomes, allowing the plant to form a network of rhizomes creating a large patch (called a clone) which is genetically distinct.[3] Floral and leaf buds develop intermittently along the stems of the plant, with each floral bud giving rise to 5–6 flowers and the eventual fruit.[3] Wild blueberries prefer an acidic soil between 4.2 and 5.2 pH and only moderate amounts of moisture.[3] They have a hardy cold tolerance in their range in Canada and the northern United States.[3] Fruit productivity of lowbush blueberries varies by the degree of pollination, genetics of the clone, soil fertility, water availability, insect infestation, plant diseases, and local growing conditions.[3] Wild (lowbush) blueberries have an average mature weight of 0.3 grams (1128 oz).[3]

    Lowbush blueberries, sometimes called “wild blueberries”, are generally not planted by farmers, but rather are managed on berry fields called “barrens”.[4] Cultivated highbush blueberries prefer sandy or loam soils, having shallow root systems that benefit from mulch and fertilizer.[5] The leaves of highbush blueberries can be either deciduous or evergreen, ovate to lanceolate, and 1–8 cm (12–3+14 in) long and 0.5–3.5 cm (14–1+38 in) broad. The flowers are bell-shaped, white, pale pink or red, sometimes tinged greenish.

    The fruit is a berry 5–16 mm (31658 in) in diameter with a flared crown at the end; they are pale greenish at first, then reddish-purple, and finally uniformly blue when ripe.[5] They are covered in a protective coating of powdery epicuticular wax, colloquially known as the “bloom”.[3] They generally have a sweet taste when mature, with variable acidity.[3][5] Blueberry bushes typically bear fruit in the middle of the growing season: fruiting times are affected by local conditions, such as climate, altitude, and latitude, so the time of harvest in the northern hemisphere can vary from May to August.[3][5]

    Identification

    [edit]

    Commercially offered blueberries are usually from species that naturally occur only in eastern and north-central North America. Other sections in the genus are native to other parts of the world, including the Pacific Northwest and the southern United States,[6] South America, Europe and Asia. Other wild shrubs in many of these regions produce similar-looking edible berries, such as huckleberries and whortleberries (North America) and bilberries (Europe). These species are sometimes called “blueberries” and are sold as blueberry jam or other products.

    The names of blueberries in languages other than English often translate as “blueberry”, e.g. Scots blaeberry and Norwegian blåbærBlaeberryblåbær and French myrtilles usually refer to the European native V. myrtillus (bilberry), while bleuets refers to the North American blueberry.

    Cyanococcus blueberries can be distinguished from the nearly identical-looking bilberries by their flesh color when cut in half. Ripe blueberries have light green flesh, while bilberries, whortleberries, and huckleberries are red or purple throughout.

    Species

    [edit]

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    Note: habitat and range summaries are from the Flora of New Brunswick, published in 1986 by Harold R. Hinds, and Plants of the Pacific Northwest coast, published in 1994 by Pojar and MacKinnon.

    Some other blue-fruited species of Vaccinium:

    • Wild blueberry in autumn foliage, Pilot Mountain, North Carolina, in October
    • A maturing ‘Polaris’ blueberry (Vaccinium corymbosum)
    • A selection of blueberries, showing the typical sizes of the berries. The scale is marked in centimeters.

    The lowbush varieties are V. angustifoliumV. borealeV. mytilloidesV. pallidum, and V. angustifolium × V. corymbosum. They are still grown similarly to pre-Columbian semi-wild cultivation, i.e. slash and burn. The highbush varieties are darrowii and corymbosum. Rabbiteye (V. ashei/V. virgatum) differ from both high- and lowbush.[8]

    Distribution

    [edit]

    Flowers on a cultivated blueberry bush
    Fresh blueberries

    Vaccinium has a mostly circumpolar distribution, with species mainly present in North America, Europe, and Asia.[1] Many commercially available species with English common names including “blueberry” are from North America,[8] particularly Atlantic Canada and the northeastern United States for wild (lowbush) blueberries, and several US states and British Columbia for cultivated (highbush) blueberries.[4][9]

    North American native species of blueberries are grown commercially in the Southern Hemisphere in Australia, New Zealand and South American nations. Vaccinium meridionale (the Andean blueberry) is wild-harvested and commonly available locally.[10] Several other wild shrubs of the genus Vaccinium also produce commonly eaten blue berries, such as the predominantly European V. myrtillus and other bilberries, which in many languages have a name that translates to “blueberry” in English.

    Cultivation

    [edit]

    Blueberry harvester in Michigan

    Blueberries may be cultivated, or they may be picked from semiwild or wild bushes. In North America, the most common cultivated species is V. corymbosum, the northern highbush blueberry. Hybrids of this with other Vaccinium species adapted to southern U.S. climates are known collectively as southern highbush blueberries.[11] Highbush blueberries were first cultivated in New Jersey around the beginning of the 20th century.[9][8]

    So-called “wild” (lowbush) blueberries, smaller than cultivated highbush ones, have intense color. V. angustifolium (lowbush blueberry) is found from the Atlantic provinces westward to Quebec and southward to Michigan and West Virginia. In some areas, it produces natural “blueberry barrens”, where it is the dominant species covering large areas. Several First Nations communities in Ontario are involved in harvesting wild blueberries.

    “Wild” has been adopted as a marketing term for harvests of managed native stands of lowbush blueberries. The bushes are not planted or selectively bred, but they are pruned or burned over every two years, and pests are “managed”.[12]

    Numerous highbush cultivars of blueberries are available, with diversity among them, each having individual qualities. A blueberry breeding program has been established by the USDA-ARS breeding program at Beltsville, Maryland, and Chatsworth, New Jersey. This program began when Frederick Vernon Coville of the USDA-ARS collaborated with Elizabeth Coleman White of New Jersey.[13] In the early part of the 20th century, White offered pineland residents cash for wild blueberry plants with unusually large fruit.[14] After 1910 Coville began to work on blueberry, and was the first to discover the importance of soil acidity (blueberries need highly acidic soil), that blueberries do not self-pollinate, and the effects of cold on blueberries and other plants.[15] In 1911, he began a program of research in conjunction with White, daughter of the owner of the extensive cranberry bogs at Whitesbog in the New Jersey Pine Barrens. His work doubled the size of some strains’ fruit, and by 1916, he had succeeded in cultivating blueberries, making them a valuable crop in the Northeastern United States.[14][16] For this work he received the George Roberts White Medal of Honor from the Massachusetts Horticultural Society.

    The rabbiteye blueberry (Vaccinium virgatum syn. V. ashei) is a southern type of blueberry produced from the Carolinas to the Gulf Coast states. Production of rabbiteye blueberries was a focus in Texas in the early 21st century.[17] Other important species in North America include V. pallidum, the hillside or dryland blueberry. It is native to the eastern U.S., and common in the Appalachians and the Piedmont of the Southeast. Sparkleberry, V. arboreum, is a common wild species on sandy soils in the Southeast.

    Successful blueberry cultivation requires attention to soil pH (acidity) measurements in the acidic range.[18][19][20]

    Blueberry bushes often require supplemental fertilization,[19] but over-fertilization with nitrogen can damage plant health, as evidenced by nitrogen burn visible on the leaves.[18][19]

    Growing regions

    [edit]

    Worldwide highbush blueberry growing areas (data from 2008)

    Significant production of highbush blueberries occurs in British ColumbiaMarylandWestern OregonMichiganNew JerseyNorth Carolina, and Washington. The production of southern highbush varieties occurs in California, as varieties originating from University of FloridaConnecticutNew HampshireNorth Carolina State University and Maine have been introduced. Peru, Spain, and Mexico also have significant production, as of 2018 (see Production).[21]

    United States

    [edit]

    In 2018, Oregon produced the most cultivated blueberries, recording 59 million kilograms (131 million pounds), an amount slightly exceeding the production by Washington.[22] In descending order of production volume for 2017, other major producers were GeorgiaMichiganNew Jersey, California, and North Carolina.[23]

    Hammonton, New Jersey, claims to be the “Blueberry Capital of the World”,[24] with over 80% of New Jersey’s cultivated blueberries coming from this town.[25] Every year the town hosts a large festival, which draws thousands of people to celebrate the fruit.[26]

    Maine is known for its wild blueberries,[27] but the state’s lowbush (wild) and highbush blueberries combined account for 10% of all blueberries grown in North America. Some 44,000 hectares (110,000 acres) are farmed, but only half of this acreage is harvested each year due to variations in pruning practices.[28] The wild blueberry is the official fruit of Maine.[29]

    Canada

    [edit]

    Wild blueberry fields in Nova Scotia, Canada

    Canadian production of wild and cultivated blueberries in 2015 was 166,000 tonnes valued at $262 million, the largest fruit crop produced nationally accounting for 29% of all fruit value.[30]

    British Columbia was the largest Canadian producer of cultivated blueberries, yielding 70,000 tonnes in 2015,[30] the world’s largest production of blueberries by region.[31]

    Atlantic Canada contributes approximately half of the total North American wild/lowbush annual production with New Brunswick having the largest in 2015, an amount expanding in 2016.[32] Nova Scotia, Prince Edward Island and Québec are also major producers.[33] Nova Scotia recognizes the wild blueberry as its official provincial berry,[34] with the town of Oxford, Nova Scotia known as the Wild Blueberry Capital of Canada.[35]

    Québec is a major producer of wild blueberries, especially in the regions of Saguenay-Lac-Saint-Jean (where a popular name for inhabitants of the regions is bleuets, or “blueberries”) and Côte-Nord, which together provide 40% of Québec’s total provincial production. This wild blueberry commerce benefits from vertical integration of growing, processing, frozen storage, marketing, and transportation within relatively small regions of the province.[36] On average, 80% of Québec wild blueberries are harvested on farms (21 million kilograms (23,000 short tons)), the remaining 20% being harvested from public forests (5 million kilograms (5,500 short tons)).[36] Some 95% of the wild blueberry crop in Québec is frozen for export out of the province.[36]

    Vaccinium meridionale, a wild species found in the Andes[citation needed]

    Europe

    [edit]

    Highbush blueberries were first introduced to Germany, Sweden, and the Netherlands in the 1930s, and have since been spread to numerous other countries of Europe.[2] V. corymbosum only began to be cultivated in Romania in a few years leading up to 2018 and rapidly increased in production and sales in that time (as with berries in general). As of 2018 it remains relatively unmolested by pests and diseases (see Diseases below).[37]

    Southern Hemisphere

    [edit]

    In the Southern Hemisphere, Brazil, Chile, ArgentinaPeruUruguay, New Zealand, Australia, South Africa,[38] and Zimbabwe grow blueberries commercially.[39]

    In Brazil, blueberries are produced in the states of Rio Grande do Sul, Santa Catarina, Paraná, São Paulo and Minas Gerais.[40]

    Blueberries were first introduced to Australia in the 1950s, but the effort was unsuccessful. In the early 1970s, the Victorian Department of Agriculture imported seed from the U.S. and a selection trial was started. This work was continued into the mid-1970s when the Australian Blueberry Growers’ Association was formed.[41]

    In the 21st century, the industry grew in Argentina: “Argentine blueberry production has increased over the last three years with planted area up to 400 percent,” according to a 2005 report by the U.S. Department of Agriculture.[42] “Argentine blueberry production has thrived in four different regions: the province of Entre Rios in northeastern Argentina, the province of Tucuman, the province of Buenos Aires and the southern Patagonian valleys”, according to the report.[43] In the Bureau of International Labor Affairs report of 2014 on child labor and forced labor, blueberries were listed among the goods produced in such working conditions in Argentina.[44]

    Pests and diseases

    [edit]

    Diseases

    [edit]

    Main article: List of Vaccinium diseases

    As of 2018 V. corymbosum remains relatively unmolested by pests and diseases in Romania, with Phytophthora cinnamomiMonilinia vaccinii-corymbosiBotryosphaeria corticisGodronia cassandraePhomopsis sp., Botrytis cinereaNaohidemyces vacciniiMicrosphaera penicillata var. vaccinii, and various viruses being the most common.[37]

    Pest management

    [edit]

    Pesticides

    [edit]

    DDT began to be used in blueberry soon after its discovery in 1939, and a few years later in the mid-1940s research began into its use in North America.[8]

    Because “wild” is a marketing term generally used for all low-bush blueberries, it does not indicate that such blueberries are free from pesticides.[45]

    Insecticide modes of action must be varied to avoid encouraging resistance in the invasive pest Drosophila suzukii.[8]

    Some insecticides can be counterproductive, harming natural enemies of pests as well. For example, treatment for Illinoia pepperi can reduce populations of its predatorsKaolin clay for Rhagoletis mendax also reduced effectiveness of Diachasma alloeum, its parasitoid. The pest predator Harpalus erraticus maintains greater abundance with selective insecticides rather than broad-spectrum MoAs.[8]

    Integrated pest management

    [edit]

    Blueberries are naturally relatively unmolested by arthropod pests. Nonetheless, there are 24 insect taxa known to be pest (organism)s in North America, the worst in New Jersey, MichiganMaine, and Eastern Canada being Rhagoletis mendax. Secondary but still important are Acrobasis vacciniiGrapholita packardi, and Conotrachelus nenuphar. These four are the most common targets for the development of IPM practices. as of 2019, IPM research has also taken an interest in Drosophila suzukii and arthropods like aphids (that vector diseases such as scorch virus and shoestring virus) and cicadellids (vectoring the phytoplasma that causes blueberry stunt). Managing pests down to the cosmetic level is necessary for this fruit because they are a premium product.[8]

    Changes in locale and environment – to new geographies, and into greenhouses – have required new pest management regimes, including innovative IPM. Conversely, importing foreign potential enemies into North America may yield good results: Operophtera brumata is a pest of blueberries and birches which is successfully parasitized by Cyzenis albicans despite the lack of historical, natural contact between the two. The same results were obtained with Scirtothrips citri and Beauveria bassiana. Results are available for Choristoneura rosaceana and overwhelming numbers of Trichogramma minutum, and Cyclocephala longula overwhelmed by Steinernema scarabaei. This has also been attempted with flower thrips and potential predators but with inconclusive results.[8]

    International quarantine

    [edit]

    Rhagoletis mendax is a quarantine pest in phytosanitary regimes of some countries around the world.[8]

    Resistant cultivars

    [edit]

    Insect resistance was not a priority in breeding programs until about the year 2000 and is still not a high priority. However, it may become more common as it becomes easier, especially using marker-assisted breedingV. ashei is naturally more resistant than V. corymbosum to Scaphytopius magdalensisV. ashei is less resistant than V. darrowii to Prodiplosis vaccinia. There is variation between cultivars of V. ashei in resistance to Oberea myops. There is variation in resistance among cultivars of V. corymbosum to Acrobasis vaccinii and Popillia japonica. Wild V. spp. have greater resistance than highbush cultivars to I. pepperi. There is significant variation between highbush cultivars in the abundance of various Tephritidae, thrips, and Homalodisca vitripennis.[8]

    Production

    [edit]

    CountryProduction
    (tonnes)
     United States351,130
     Peru227,971
     Canada146,551
     Chile122,795
     Mexico66,482
     Spain61,230
    World1,113,261
    Source: FAOSTAT of the United Nations[46]

    In 2021, world production of blueberries (lowbush and highbush combined) was 1.1 million tonnes, led by the United States with 32% of global production, Peru with 20%, and Canada with 13%.[46]

    In 2019, Canada was the largest producer of wild blueberries, mainly in Quebec and the Atlantic provinces,[47] but Canadian production of wild blueberries decreased since 2017 by transitioning to the more profitable cultivated highbush blueberries.[48] British Columbia produced 93% of the Canadian highbush blueberry crop in 2019.[47]

    Regulations

    [edit]

    Canada No. 1 blueberries are all similar in size, shape, weight, and color—the total product can be no more than ten percent off-color and three percent otherwise defective.[49]

    A dish of blueberries
    Nutritional value per 100 g (3.5 oz)
    Energy240 kJ (57 kcal)
    Carbohydrates14.49 g
    Sugars9.96 g
    Dietary fiber2.4 g
    Fat0.33 g
    Protein0.74 g
    showVitamins and minerals
    Other constituentsQuantity
    Water84 g
    Link to USDA Database entry
    Percentages estimated using US recommendations for adults,[50] except for potassium, which is estimated based on expert recommendation from the National Academies.[51]

    Uses

    [edit]

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    First Nations peoples of Canada consumed wild blueberries for millennia.[4]

    Blueberries are sold fresh or are processed as individually quick frozen fruit, purée, juice, or dried or infused berries. These may then be used in a variety of consumer goods, such as jelliesjamspiesmuffins, snack foods, pancakes, or as an additive to breakfast cereals.

    Blueberry jam is made from blueberries, sugar, water, and fruit pectinBlueberry sauce is a sweet sauce prepared using blueberries as a primary ingredient.

    Blueberry wine is made from the flesh and skin of the berries, which is fermented and then matured; usually, the lowbush variety is used.

    Nutrients

    [edit]

    Blueberries consist of 14% carbohydrates, 0.7% protein, 0.3% fat, and 84% water. They contain only negligible amounts of micronutrients, with moderate levels (relative to respective Daily Values) (DV) of the essential dietary mineral manganesevitamin Cvitamin K and dietary fiber. Generally, the nutrient contents of blueberries are a low percentage of the DV. A 100-gram serving provides a relatively low amount of food energy – 240 kilojoules (57 kcal) – with a glycemic load of 6.

    Phytochemicals and research

    [edit]

    Blueberries contain anthocyanins, other polyphenols and various phytochemicals under preliminary research for their potential biological effects.[52] Most polyphenol studies have been conducted using the highbush cultivar of blueberries (V. corymbosum), while content of polyphenols and anthocyanins in lowbush (wild) blueberries (V. angustifolium) exceeds values found in highbush cultivars.[53]

    • A cut blueberry showing how, having been frozen and then thawed, the anthocyanins in the pericarp can run into the damaged cells, staining the flesh.
    • Core structure common to all anthocyanins, some of which produce the blue pigments in blueberries.[52]
  • Lemon 

    The lemon (Citrus × limon) is a species of small evergreen tree in the Citrus genus of the flowering plant family Rutaceae. The lemon is a hybrid of the citron and the bitter orange. Its origins are uncertain, but some evidence suggests lemons originated during the 1st millennium BC in what is now northeastern India.

    The yellow fruit of the lemon tree is used throughout the world, primarily for its juice. The pulp and rind are used in cooking and baking. The juice of the lemon is about 5–6% citric acid, giving it a sour taste. This makes it a key ingredient in drinks and foods such as lemonade and lemon meringue pie.

    In 2022, world production was 22 million tonnes, led by India with 18% of the total.

    Description

    The lemon tree produces a pointed oval yellow fruit. Botanically this is a hesperidium, a modified berry with a tough, leathery rind. The rind is divided into an outer colored layer or zest, which is aromatic with essential oils, and an inner layer of white spongy pith. Inside are multiple carpels arranged as radial segments. The seeds develop inside the carpels. The space inside each segment is a locule filled with juice vesicles.[2]

    Lemons contain many phytochemicals, including polyphenolsterpenes, and tannins.[3] Their juice contains slightly more citric acid than lime juice (about 47 g/L), nearly twice as much as grapefruit juice, and about five times as much as orange juice.[4]

    • Lemon seedling
    • Full-sized tree
    • Flower
    • Mature lemons

    Origins

    See also: Citrus taxonomy

    The lemon, like many other cultivated Citrus species, is a hybrid, in its case of the citron and the bitter orange.[5][6]

    The lemon is a hybrid of the citron and the bitter orange.[6]
    Taxonomic illustration by Franz Eugen Köhler, 1897

    Lemons were most likely first grown in northeast India.[7] The origin of the word lemon may be Middle Eastern.[7] The word draws from the Old French limon, then Italian limone, from the Arabic ليمون laymūn or līmūn, and from the Persian لیمو līmūn, a generic term for citrus fruit, which is a cognate of Sanskrit (nimbū, ‘lime‘).[8]

    Lemons entered Europe near southern Italy no later than the second century AD, during the time of Ancient Rome.[7] They were later introduced to Persia and then to Iraq and Egypt around 700 AD.[7] The lemon was first recorded in literature in a 10th-century Arabic treatise on farming; it was used as an ornamental plant in early Islamic gardens.[7] It was distributed widely throughout the Arab world and the Mediterranean region in the Arab Agricultural Revolution between 1000 and 1150.[7] A section on lemon and lime tree cultivation in AndalusiaSpain, was included in Ibn al-‘Awwam‘s 12th-century agricultural work, Kitāb al-Filāha (“Book on Agriculture”).[9] The first substantial cultivation of lemons in Europe began in Genoa in the middle of the 15th century. It was introduced to the Americas in 1493, when Christopher Columbus brought lemon seeds to Hispaniola on his voyages. Spanish conquest throughout the New World helped spread lemon seeds, part of the Columbian exchange of plants between the Old and New Worlds. It was mainly used as an ornamental plant and for medicine.[7] In the 19th century, lemons were increasingly planted in Florida and California.[7] In 1747, the English physician James Lind‘s experiments on seamen suffering from scurvy involved adding lemon juice to their diets, though vitamin C was not yet known as an important dietary ingredient.[7][10]

    Cultivation

    Growing and pruning

    Lemons need a minimum temperature of around 7 °C (45 °F), so they are not hardy year-round in temperate climates, but become hardier as they mature.[11] Citrus require minimal pruning by trimming overcrowded branches, with the tallest branch cut back to encourage bushy growth.[11] Throughout summer, pinching back tips of the most vigorous growth assures more abundant canopy development. As mature plants may produce unwanted, fast-growing shoots (called “water shoots”), these are removed from the main branches at the bottom or middle of the plant.[11] There is reputed merit in the tradition of urinating near a lemon tree.[12][13]

    In cultivation in the UK, the cultivars “Meyer”[14] and “Variegata”[15] have gained the Royal Horticultural Society‘s Award of Garden Merit (confirmed 2017).[16]

    Production

    Lemon (and lime) production, 2022millions of tonnes
    Country2022
     India3.8
     Mexico3.1
     China2.6
     Argentina1.8
     Brazil1.6
     Turkey1.3
    World21.5
    Source: FAOSTAT of the United Nations.[17]

    In 2022, world production of lemons (combined with limes for reporting) was 22 million tonnes led by India with 18% of the total. Mexico and China were major secondary producers (table).

    Varieties

    The ‘Bonnie Brae’ is oblong, smooth, thin-skinned, and seedless.[18] These are mostly grown in San Diego County, US.[19]

    The ‘Eureka’ grows year-round and abundantly. This is the common supermarket lemon, also known as “Four Seasons” (Quatre Saisons) because of its ability to produce fruit and flowers together throughout the year. This variety is also available as a plant for domestic customers.[20] There is also a pink-fleshed Eureka lemon with a green and yellow variegated outer skin.[21]

    The Lisbon lemon is very similar to the Eureka and is the other common supermarket lemon. It is smoother than the Eureka, has thinner skin, and has fewer or no seeds. It generally produces more juice than the Eureka.[22][23]

    The ‘Femminello St. Teresa’, or ‘Sorrento’ originates in Italy. This fruit’s zest is high in lemon oils. It is the variety traditionally used in the making of limoncello.[24]

    The ‘Yen Ben’ is an Australasian cultivar.[25]

    Uses

    Nutrition

    Nutritional value per 100 g (3.5 oz)
    Energy121 kJ (29 kcal)
    Carbohydrates9.32 g
    Sugars2.5 g
    Dietary fiber2.8 g
    Fat0.3 g
    Protein1.1 g
    showVitamins and minerals
    Link to USDA Database entry
    Percentages estimated using US recommendations for adults,[26] except for potassium, which is estimated based on expert recommendation from the National Academies.[27]

    Lemon is a rich source of vitamin C, providing 64% of the Daily Value in a 100 g reference amount (table). Other essential nutrients are low in content.

    Culinary

    See also: List of lemon dishes and drinks

    Lemon juice and rind are used in a wide variety of foods and drinks, the juice for its sour taste, from its content of 5–6% citric acid.[28] The whole lemon is used to make marmalade,[29] lemon curd[30] and lemon liqueurs such as Limoncello.[31] Lemon slices and lemon rind are used as a garnish for food and drinks. Lemon zest, the grated outer rind of the fruit, is used to add flavor to baked goods.[32] The juice is used to make lemonade[33] and some cocktails.[34]

    It is used in marinades for fish, where its acid neutralizes amines in fish.[35] In meat, the acid partially hydrolyzes tough collagen fibers, tenderizing it.[36] In the United Kingdom, lemon juice is frequently added to pancakes eaten to celebrate Shrove Tuesday.[37] Lemon juice is used as a short-term preservative on certain foods that tend to oxidize and turn brown after being sliced (enzymatic browning), such as applesbananas, and avocados: its acidity suppresses oxidation by polyphenol oxidase enzymes.[38]

    Lemon peel is used in the manufacture of pectin, a gelling agent and stabilizer in food and other products.[39] In Mediterranean countries including Morocco, lemons are preserved in jars or barrels of salt. The salt penetrates the peel and rind, softening them, and curing them so that they last almost indefinitely.[40]

    Lemon oil is extracted from oil-containing cells in the skin. A machine breaks up the cells and uses a water spray to flush off the oil. The oil–water mixture is then filtered and separated by centrifugation.[41]

    The leaves of the lemon tree are used to make a tea and for preparing cooked meats and seafoods.[42]

    Other uses

    Lemons were the primary commercial source of citric acid before the development of fermentation-based processes.[43] Lemon oil is used in aromatherapy. Lemon oil aroma does not influence the human immune system,[44] but may contribute to relaxation.[45] An educational science experiment involves attaching electrodes to a lemon and using it as a battery to produce electricity. Although very low power, several lemon batteries can power a small digital watch.[46] Lemon juice forms a simple invisible ink, developed by heat.[47] Lemon juice is sometimes used to increase the blonde color of hair, acting as a natural highlight after the moistened hair is exposed to sunlight. This works because citric acid acts as bleach.[48][49]

    Other citrus called ‘lemons’

    In art and culture

    Lemons appear in paintings, pop art, and novels.[52] A wall painting in the tomb of Nakht in 15th century BC Egypt depicts a woman in a festival, holding a lemon. In the 17th century, Giovanna Garzoni painted a Still Life with Bowl of Citrons, the fruits still attached to leafy flowering twigs, with a wasp on one of the fruits. The impressionist Edouard Manet depicted a lemon on a pewter plate. In modern art, Arshile Gorky painted Still Life with Lemons in the 1930s.[52]

    In India, a lemon may be ritually encircled around a person in the belief that it repels negative energies.[53] It is a common practice for Hindu owners of a new car to drive over four lemons, one under each wheel, crushing them during their first drive. This is believed to protect the driver from accidents.[54] Hindu deities are sometimes depicted with lemons in their iconography, representing the attribute of wealth or abundance.[55]

    In 20th century American self-improvement culture, Dale Carnegie advised readers “If You Have a Lemon, Make a Lemonade”, meaning to make the best of what you have. In the 21st century, a defective machine such as a car is called a lemon.[56]