Amaranthus | |
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Amaranthus caudatus | |
Scientific classification | |
Kingdom: | Plantae |
(unranked): | Angiosperms |
(unranked): | Eudicots |
(unranked): | Core eudicots |
Order: | Caryophyllales |
Family: | Amaranthaceae |
Subfamily: | Amaranthoideae |
Genus: | Amaranthus L. |
Species | |
See text. |
Amaranthus, collectively known as amaranth, is a cosmopolitan genus of herbs. Approximately 60 species are recognized, with inflorescences and foliage ranging from purple and red to gold. Members of this genus share many characteristics and uses with members of the closely related genus Celosia.
Although several species are often considered weeds, people around the world value amaranths as leaf vegetables, cereals, and ornamentals.
The ultimate root of "amaranth" is the Greek ἀμάραντος[1] (amarantos) "unfading" with the Greek word for "flower" ἄνθος (anthos) factoring into the word's development as "amaranth" - the more correct "amarant" is an archaic variant.
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Amaranthus shows a wide variety of morphological diversity among and even within certain species. Although the family (Amaranthaceae) is distinctive, the genus has few distinguishing characters among the 70 species included.[2] This complicates taxonomy and Amaranthus has generally been considered among systematists as a "difficult" genus.[3]
Formerly, Sauer (1955) classified the genus into 2 sub-genera, differentiating only between monoecious and dioecious species: Acnida (L.) Aellen ex K.R. Robertson and Amaranthus.[3] Although this classification was widely accepted, further infrageneric classification was (and still is) needed to differentiate this widely diverse group.
Currently, Amaranthus includes 3 recognized sub-genera and 70 species, although species numbers are questionable due to hybridization and species concepts.[4] Infrageneric classification focuses on inflorescence, flower characters and whether a species is monoecious/dioecious, as in the Sauer (1955) suggested classification.[2] A modified infrageneric classification of Amaranthus was published by Mosyakin & Robertson (1996) and includes 3 subgenera: Acnida, Amaranthus, and Albersia. The taxonomy is further differentiated by sections within each of the sub-genera.[5]
Several species are raised for amaranth "grain" in Asia and the Americas. This should more correctly be termed "pseudograin" (see below). Amaranth grain contains no gluten and is safe to consume for individuals with coeliac disease.[7]
Ancient amaranth grains still used to this day include the three species, Amaranthus caudatus, Amaranthus cruentus, and Amaranthus hypochondriacus.[8] Although amaranth was cultivated on a large scale in ancient Mexico, Guatemala, and Peru, nowadays it is only cultivated on a small scale there, along with India, China, Nepal, and other tropical countries; thus, there is potential for further cultivation in those countries, as well as in the U.S. In a 1977 article in Science, amaranth was described as "the crop of the future."[9] It has been proposed as an inexpensive native crop that could be cultivated by indigenous people in rural areas for several reasons:
Kiwicha, as amaranth is known today in the Andes, was one of the staple foodstuffs of the Incas. Known to the Aztecs as huautli, it is thought to have represented up to 80% of their caloric consumption before the conquest. Another important use of amaranth throughout Mesoamerica was to prepare ritual drinks and foods. To this day, amaranth grains are toasted much like popcorn and mixed with honey, molasses or chocolate to make a treat called alegría, meaning "joy" in Spanish. Diego Duran described the festivities for Huitzilopochtli, a blue hummingbird god. (Real hummingbirds feed on amaranth flowers.) The Aztec month of Panquetzaliztli (7 December to 26 December) was dedicated to Huitzilopochtli. People decorated their homes and trees with paper flags; there were ritual races, processions, dances, songs, prayers, and finally human sacrifices. This was one of the more important Aztec festivals, and the people prepared for the whole month. They fasted or ate very little; a statue of the god was made out of amaranth (huautli) seeds and honey, and at the end of the month, it was cut into small pieces so everybody could eat a little piece of the god. After the Spanish conquest, cultivation of amaranth was outlawed, while some of the festivities were subsumed into the Christmas celebration.
Because of its importance as a symbol of indigenous culture, its gluten-free palatability, easy to cook, and its protein particularly well suited to human nutritional needs, interest in grain amaranth (especially A. cruentus and A. hypochondriacus) revived in the 1970s. It was recovered in Mexico from wild varieties and is now commercially cultivated. It is a popular snack sold in Mexico City and other parts of Mexico, sometimes mixed with chocolate or puffed rice, and its use has spread to Europe and parts of North America. Amaranth and quinoa are called pseudograins because of their flavor and cooking similarities to grains.
Amaranth seed, when properly prepared, may supplement human food. Scientific studies suggest Amaranth grain is a good source of essential amino acid lysine, something other grains are low in. Amaranth is not a complete source of essential amino acids. For example, amaranth is limiting in leucine and threonine - essential amino acids that are abundant in other grains. Amaranth may therefore be a promising supplement to other grains.[13],[14] The assimiability of protein in Amaranth is affected by the anti-nutritional factors present in Amaranth, and how it is processed and cooked prior to human consumption. Wet heat processing reduces toxic factors and improves protein availability from Amaranth, while popping and toasting reduces nutritional value of Amaranth.[14] Besides protein, amaranth grain provides a good complimentary source of dietary fiber and dietary minerals such as iron, magnesium, phosphorus, copper, and manganese.
Amaranth seed flour has been evaluated as an additive to wheat flour by food specialists. To determine palatability, different levels of amaranth grain flour were mixed with the wheat flour and baking ingredients (1% salt, 2.5% fat, 1.5% yeast, 10% sugar and 52–74% water), fermented, molded, pan-proved and baked. The baked products were evaluated for loaf volume, moisture content, color, odor, taste and texture. The amaranth containing products were then compared with bread made from 100% wheat flour. The loaf volume decreased by 40% and the moisture content increased from 22 to 42% with increase in amaranth grain flour. The study found that the sensory scores of the taste, odor color and texture decreased with increasing amounts of amaranth. Generally, above 15% amaranth grain flour, there were significant differences in the evaluated sensory qualities and the high amaranth-containing product was found to be of unacceptable palatability to the population sample that evaluated the baked products.[15]
Amaranth species are cultivated and consumed as a leaf vegetable in many parts of the world. There are four species of Amaranthus documented as cultivated vegetables in eastern Asia: Amaranthus cruentus, Amaranthus blitum, Amaranthus dubius, and Amaranthus tricolor.[16]
In Indonesia and Malaysia, leaf amaranth is called bayam, while the Tagalogs in the Philippines call the plant alocon. In the state of Uttar Pradesh and Bihar in India, it is called Chaulai and is a popular green leafy vegetable (referred to in the class of vegetable preparations called Saag). It is called Chua in Kumaun area of Uttarakhand, where it is a popular red-green vegetable. In Karnataka state in India it is used to prepare curries like Hulee, palya, Majjigay-hulee and so on. In the state of Kerala, it's called 'Cheera' and is consumed by stir-frying the leaves with spices and red chillies to make 'Cheera Thoran'. In Tamilnadu State, it is called முளைக்கீரை and is regularly consumed as a favourite dish, where the greens are steamed, and mashed, with light seasoning of salt, red chillis and cumin. It is called keerai masial (கீரை மசியல்). In Andhra Pradesh, India, this leaf is added in preparation of a popular dal called thotakura pappu తొట కూర పప్పు (Telugu). In Maharashtra, it is called as "Shravani Maath" (literally माठ grown in month of Shravan) and it is available in both red and white colour. In Orissa, it is called as "Khada saga", it is used to prepare 'Saga Bhaja', in which the leaf is fried with chillies and onions.
The root of mature amaranth is an excellent vegetable. It is white and cooked with tomatoes or tamarind gravy. It has a milky taste and is alkaline.
In China, the leaves and stems are used as a stir-fry vegetable, or in soups, and called yin choi (苋菜; pinyin: xiàncài; and variations on this transliteration in various dialects). Amaranth greens are believed to help enhance eyesight. In Vietnam, it is called rau dền and is used to make soup. There are two species popular as edible vegetable in Vietnam: dền đỏ- amaranthus tricolor and dền cơm or dền trắng- amaranthus viridis.
A traditional food plant in Africa, amaranth has the potential to improve nutrition, boost food security, foster rural development and support sustainable landcare.[17] In East Africa, Amaranth leaf is known in chewa as bonongwe, and in Swahili as mchicha, as terere in Kikuyu, Meru and Embu; and as telele in Kamba. In Bantu regions of Uganda it is known as doodo.[18] It is recommended by some doctors for people having low red blood cell count. It is also known among the Kalenjin as a drought crop (chepkerta). In Lingala (spoken in the Democratic Republic of the Congo and the Republic of Congo), it is known as lɛngalɛnga or bítɛkutɛku.[19] In Nigeria, it is a common vegetable and goes with all Nigerian starch dishes. It is known in Yoruba as efo tete or arowo jeja (meaning "we have money left over for fish"). In the Caribbean, the leaves are called [bhaji in Trinidad) or(callaloo in Jamaica] and stewed with onions, garlic and tomatoes, or sometimes used in a soup called pepperpot soup.
In Greece, green amaranth (Amaranthus viridis) is a popular dish and is called vlita or vleeta. It's boiled, then served with olive oil and lemon like a salad, usually alongside fried fish. Greeks stop harvesting the plant (which usually grows wild) when it starts to bloom at the end of August.
In Sri Lanka, it is called "koora thampala". Sri Lankans cook it and eat it with rice. Fiji Indians call it choraiya bhaji.
The flowers of the 'Hopi Red Dye' amaranth were used by the Hopi (a tribe in the western United States) as the source of a deep red dye. There is also a synthetic dye that has been named "amaranth" for its similarity in color to the natural amaranth pigments known as betalains. This synthetic dye is also known as Red No. 2 in North America and E123 in the European Union.[20]
The genus also contains several well-known ornamental plants, such as Amaranthus caudatus (love-lies-bleeding), a native of India and a vigorous, hardy annual with dark purplish flowers crowded in handsome drooping spikes. Another Indian annual, A. hypochondriacus (prince's feather), has deeply veined lance-shaped leaves, purple on the under face, and deep crimson flowers densely packed on erect spikes.
Amaranths are recorded as food plants for some Lepidoptera (butterfly and moth) species including the nutmeg moth and various case-bearer moths of the genus Coleophora: C. amaranthella, C. enchorda (feeds exclusively on Amaranthus), C. immortalis (feeds exclusively on Amaranthus), C. lineapulvella and C. versurella (recorded on A. spinosus).
Amaranth greens, also called Chau lai (Hindi) and Chu or Chua (Kumauni), Chinese spinach, hinn choy or yin tsoi (simplified Chinese: 苋菜; traditional Chinese: 莧菜; pinyin: xiàncài); callaloo, dhantinasoppu (Kannada); తోటకూర (Telugu); Rajgira (Marathi); முளைக் கீரை (Tamil); cheera ചീര (Malayalam); bayam (Indonesian); phak khom ผักโขม (Thai); tampala, or quelite (Oriya); Khada Saga, are a common leaf vegetable throughout the tropics and in many warm temperate regions.
Cooked amaranth leaves are a good source of vitamin A, vitamin C, and folate; they are also a complementing source of other vitamins such as thiamine, niacin, and riboflavin, plus some dietary minerals including calcium, iron, potassium, zinc, copper, and manganese. Cooked amaranth grains are a complementing source of thiamine, niacin, riboflavin, and folate, and dietary minerals including calcium, iron, magnesium, phosphorus, zinc, copper, and manganese - comparable to common grains such as wheat germ, oats and others.[12]
Amaranth seeds contain lysine, an essential amino acid, limiting in other grains or plant sources.[21] Most fruits and vegetables do not contain a complete set of amino acids, and thus different sources of protein must be used. Amaranth too is limiting in some essential amino acids, such as leucine and threonine.[13] Amaranth seeds are therefore promising complement to common grains such as wheat germ, oats, corn because these common grains are abundant sources of essential amino acids found to be limited in amaranth.[22][23]
Amaranth may be a promising source of protein to those who are gluten sensitive, because unlike the protein found in grains such as wheat and rye, its protein does not contain gluten.[24] According to a 2007 report, amaranth compares well in nutrient content with gluten-free vegetarian options such as buckwheat, corn, millet, wild rice, oats and quinoa.[25]
Several studies have shown that like oats, amaranth seed or oil may be of benefit for those with hypertension and cardiovascular disease; regular consumption reduces blood pressure and cholesterol levels, while improving antioxidant status and some immune parameters.[26][27][28] While the active ingredient in oats appears to be water-soluble fiber, amaranth appears to lower cholesterol via its content of plant stanols and squalene.
Amaranth remains an active area of scientific research for both human nutritional needs and foraging applications. Over 100 scientific studies suggest a somewhat conflicting picture on possible anti-nutritional and toxic factors in amaranth, more so in some particular strains of amaranth. Lehmann, in a review article, identifies some of these reported anti-nutritional factors in amaranth to be phenolics, saponins, tannins, phytic acid, oxalates, protease inhibitors, nitrates, polyphenols and phytohemagglutinins.[29] Of these, oxalates and nitrates are of more concern when amaranth grain is used in foraging applications. Some studies suggest thermal processing of amaranth, particularly in moist environment, prior to its preparation in food and human consumption may be a promising way to reduce the adverse effects of amaranth's anti-nutritional and toxic factors.
A one-to-one comparison of cooked amaranth with cooked wild rice and with whole grain wheat flour suggests: [30][31]
Not all amaranth plants are cultivated. Most of the species from Amaranthus are summer annual weeds and are commonly referred to as pigweeds.[32] These species have an extended period of germination, rapid growth, and high rates of seed production[32], and have been causing problems for farmers since the mid-1990s. This is partially due to the reduction in tillage, reduction in herbicidal use and the evolution of herbicidal resistance in several species where herbicides have been applied more often.[33] The following 9 species of Amaranthus are considered invasive and noxious weeds in the U.S and Canada: A. albus, A. blitoides, A. hybridus, A. palmeri, A. powellii, A. retroflexus, A. spinosus, A. tuberculatus, and A. viridis.[34]
A new herbicide-resistant strain of Amaranthus palmeri or Palmer amaranth has appeared; it is Glyphosate-resistant and so cannot be killed by the widely used Roundup herbicide. Also, this plant can survive in tough conditions. This could be of particular concern to cotton farmers using Roundup Ready cotton.[35] The species Amaranthus palmeri (Palmer amaranth) causes the greatest reduction in soybean yields and has the potential to reduce yields by 17-68% in field experiments.[32] Palmer amaranth is among the “top five most troublesome weeds” in the southeast and has already evolved resistances to dinitroanilines and acetolactate synthase inhibitors.[36] This makes the proper identification of Amaranthus species at the seedling stage essential for agriculturalists. Proper weed control needs to be applied before the species successfully colonizes in the crop field and causes significant yield reductions.
Pigweed can be a beneficial weed, as well as a companion plant, serving as a trap for leaf miners and some other pests, as well as sheltering ground beetles (which prey upon insect pests) and breaking up hard soil for more delicate neighboring plants.
The word amaranth comes from the Greek word amarantos, meaning "unwithering". The word was applied to amaranth because it did not soon fade and so symbolized immortality. "Amarant" is a more correct, albeit archaic form, chiefly used in poetry. The current spelling, amaranth, seems to have come from folk etymology that assumed the final syllable derived from the Greek word anthos ("flower"), common in botanical names.
An early Greek fable ascribed counted among Aesop's Fables compares the rose to the amaranth to illustrate the difference in fleeting and everlasting beauty:
- An amaranth planted in a garden near a Rose-Tree, thus addressed it: "What a lovely flower is the Rose, a favorite alike with Gods and with men. I envy you your beauty and your perfume." The Rose replied, "I indeed, dear Amaranth, flourish but for a brief season! If no cruel hand pluck me from my stem, yet I must perish by an early doom. But thou art immortal and dost never fade, but bloomest for ever in renewed youth."[37]
In John Milton's epic Paradise Lost it is given a more fitting neighbour:
- "Immortal amarant, a flower which once
- In paradise, fast by the tree of life,
- Began to bloom; but soon for man's offence
- To heaven removed, where first it grew, there grows,
- And flowers aloft, shading the fount of life,
- And where the river of bliss through midst of heaven
- Rolls o'er elysian flowers her amber stream:
- With these that never fade the spirits elect
- Bind their resplendent locks." (III, 353)
Samuel Taylor Coleridge, in Work Without Hope (1825), also refers to the herb, likely referencing Milton's earlier work. (ll 7-10 excerpted):
In his dialogue ‘Aesop and Rhodopè’, published in 1844, Walter Savage Landor wrote:
- Yet well I ken the banks where Amaranths blow,
- Have traced the fount whence streams of nectar flow.
- Bloom, O ye Amaranths! bloom for whom ye may,
- For me ye bloom not! Glide, rich streams, away!
There are no fields of amaranth on this side of the grave: there are no voices, O Rhodopè, that are not soon mute, however tuneful: there is no name, with whatever emphasis of passionate love repeated, of which the echo is not faint at last.
Joachim du Bellay mentioned the herb in his "A Vow To Heavenly Venus," ca. 1500.
- We that with like hearts love, we lovers twain,
- New wedded in the village by thy fane,
- Lady of all chaste love, to thee it is
- We bring these amaranths, these white lilies,
- A sign, and sacrifice; may Love, we pray,
- Like amaranthine flowers, feel no decay;
- Like these cool lilies may our loves remain,
- Perfect and pure, and know not any stain;
- And be our hearts, from this thy holy hour,
- Bound each to each, like flower to wedded flower.
In ancient Greece, the amaranth (also called chrysanthemum and helichrysum) was sacred to Ephesian Artemis. It was supposed to have special healing properties, and, as a symbol of immortality, was used to decorate images of the gods and tombs. In legend, Amarynthus (a form of Amarantus) was a hunter of Artemis and king of Euboea; in a village of Amarynthus, of which he was the eponymous hero, there was a famous temple of Artemis Amarynthia or Amarysia (Strabo x. 448; Pausan. i. 31, p. 5). It was also widely used by the Chinese for its healing chemicals, curing illnesses such as infections, rashes, and migraines. The "Amarantos" is the name of a several-century-old popular Greek folk song:
- Look at the amaranth:
- on tall mountains it grows,
- on the very stones and rocks
- and places inaccessible.
Nutritional quality of amaranth
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