Ipomoea Asarifolia Descriptive Essay


Ipomoea asarifolia (Desr.) Roem. & Schult.

Protologue : Syst. Veg. 4: 251 (1819).
Famille : Convolvulaceae
Nombre de chromosomes : 2n = 30

Synonymes

  • Ipomoea repens Lam. (1791).

Noms vernaculaires

  • Salsa brava, salsa da rua (Po).

Origine et répartition géographique

L’origine d’Ipomoea asarifolia n’est pas connue. On a émis l’hypothèse qu’il serait originaire du sud de l’Inde et que d’anciens visiteurs européens l’auraient disséminé dans le monde en raison de ses usages médicinaux. Selon d’autres sources, il serait originaire de l’Amérique tropicale. Il se rencontre dans presque toutes les régions tropicales, y compris l’Afrique du Nord ; en Afrique tropicale, il est présent depuis le Cap-Vert et le Sénégal jusqu’au Soudan, en passant par le Mali et le Cameroun, et vers le sud jusqu’à l’Angola, en Zambie et au Mozambique. Il semble absent en Afrique orientale et sur les îles de l’océan Indien.

Usages

Ipomoea asarifolia a de nombreux usages médicinaux dans toute l’Afrique de l’Ouest, malgré sa toxicité. Au Togo, la racine réduite en poudre dans de l’eau se boit contre les problèmes stomachiques. La décoction de racine se prend par voie orale contre les infections dues au ver de Guinée. Au Sénégal, on applique une compresse de la plante entière broyée sur des plaies, et on boit la décoction de la plante contre les hémorragies post-partum. En Côte d’Ivoire, la pâte des tiges feuillées mélangées avec du citron et de l’eau se prend comme ecbolique. Au Togo, les feuilles réduites en pâte s’appliquent en externe contre le tétanos ou la méningite. Au Mali, la cendre des tiges feuillées mélangée au beurre de karité se donne aux malades pour redonner des forces. Au Burkina Faso, la pâte des feuilles s’utilise en lotion contre les vers intestinaux. Au Bénin, la décoction des tiges feuillées avec celles de Cissus quadrangularis L. et de Borreria sp. s’utilise en bain contre les fractures ; en mélange avec d’autres plantes, elle s’applique sur les piqûres d’insectes. La décoction de feuilles se prend contre la fièvre et les convulsions. Au Nigeria, la décoction des parties aériennes s’applique contre les furoncles et s’absorbe contre les problèmes de l’estomac. La décoction de feuilles se prend en breuvage ou en lotion contre les refroidissements fébriles et les douleurs rhumatismales. Au Nigeria et en Mauritanie, les feuilles s’appliquent en cataplasme sur les plaies dues au ver de Guinée. Au Nigeria, les fleurs cuites avec des haricots se consomment en remède contre la syphilis. Dans le nord du Ghana, les bovins atteints de la maladie “garli” sont traités avec des concoctions de tiges et de racines en mélange avec celles d’autres plantes. Cette infusion est donnée à boire à l’animal, tandis que le charbon pulvérisé des plantes brûlées, mélangé au beurre de karité, est frictionné sur les articulations. La plante contient des substances toxiques et n’est pas consommée par l’homme, ni par les animaux brouteurs. Cependant, les jeunes feuilles seraient consommées en soupes pendant la saison sèche dans le nord du Bénin. Dans le nord du Nigeria, il provoquerait de la diarrhée chez les chevaux s’ils le broutent accidentellement, et il cause la folie et la mort chez les chameaux. Les chameaux au Sénégal, les moutons en Mauritanie et les poules au Soudan en consommeraient de petites quantités. Au Brésil, on a observé que la folie est un des symptômes associés à la consommation de la plante. Au Sénégal, la décoction de la plante s’utilise pour teindre les étoffes et les cheveux en noir, alors qu’en Mauritanie les cendres de la plante mélangées à l’indigo fournissent un colorant bleu pour les tissus. Les tiges séchées servent d’amadou, et les feuilles s’utilisent parfois pour envelopper les pieds et les mains après l’application de henné. La plante rampe sur les dunes de sable et est utile pour fixer le sable. Les longues tiges servent de cordes.

Production et commerce international

Ipomoea asarifolia n’est vendu que localement.

Propriétés

L’extrait des feuilles contient des glucides, des tanins, des saponines, des terpènes et des stéroïdes. Deux anthocyanines triacylées et tétraglucosylées, dérivées de la cyanidine, ont été isolées des fleurs. On a isolé quatre anthocyanines acylées des parties aériennes. Egalement des alcaloïdes du type ergoline ont été isolés des parties aériennes, mais on a trouvé qu’ils dérivent de champignons de la famille des Clavicipitaceae, champignons qui sont associés à la plante. Ce sont ces composés qui sont responsables pour les empoisonnements occasionnels chez les bovins, les moutons et les chèvres.

Les extraits à l’éthanol et à l’acétate d’éthyle de la plante ont montré un fort effet inhibiteur de l’acétylcholinestérase in vitro. Dans un essai de laboratoire, on a trouvé que l’extrait de feuilles contient des composés hépatoprotecteurs et même curatifs puissants contre les lésions hépatiques induites au CCl4 chez le rat, comme en témoignent les taux réduits d’enzymes indicatrices et la réduction des lésions induites au CCl4, qui est comparable à l’effet du médicament silymarine.

L’effet antinociceptif de l’extrait au méthanol des feuilles s’est montré par sa capacité à réduire le nombre des contorsions abdominales induites à l’acide acétique chez la souris. L’extrait montre une inhibition prolongée et puissante des douleurs, indication de propriétés antinociceptives ainsi qu’anti-inflammatoires.

L’analyse de la valeur nutritionnelle des feuilles d’Ipomoea asarifolia a montré la présence de quantités appréciables de protéines brutes (21 g par 100 g de matière sèche). Les niveaux de plomb, d’oxalates et de phytates dans les échantillons de la plante étaient bas comparés aux teneurs maximales permises pour ces composés. Cependant, le risque d’une intoxication qui ressemble à l’ergotisme réduit énormément la valeur de la plante comme fourrage.

Falsifications et succédanés

Ipomoea asarifolia et Ipomoea pes-caprae (L.) R.Br. se ressemblent beaucoup et s’utilisent souvent à des fins similaires.

Description

Plante herbacée vivace, glabre, rampante, atteignant 3 m de long, à courtes pousses érigées ; tiges épaisses, cylindriques ou anguleuses. Feuilles alternes, simples et entières ; pétiole de 3–8,5 cm de long, assez épais, profondément sillonné au-dessus, lisse ou finement muriqué ; limbe circulaire à réniforme, de 3,5–7 cm × 3,5–8,5 cm, base cordée à lobes arrondis, apex arrondi, parfois émarginé, mucronulé, coriace, plié le long de la nervure médiane. Inflorescence : cyme axillaire, souvent accompagnée d’une pousse feuillée axillaire, portant 1 à quelques fleurs ; pédoncule de 2–5 cm de long ; bractées ovales, minuscules. Fleurs bisexuées, presque régulières, 5-mères ; pédicelle de 1,5–3 cm de long ; sépales inégaux, elliptiques-oblongs, obtus, mucronulés, les sépales internes de 8–11 mm de long, les sépales externes de 5–8 mm de long, plus ou moins muriqués ; corolle en entonnoir, jusqu’à 6,5 cm de long, violet rosé avec un centre plus foncé ; étamines 5, insérées près de la base du tube de la corolle, filets filiformes, inégaux en longueur ; disque annulaire ; ovaire supère, glabre, style filiforme, inclus, stigmate 2-globuleux. Fruit : capsule globuleuse, glabre, de 1–1,5 cm de diamètre. Graines de 5–7 mm de long, noires, glabres.

Autres données botaniques

Ipomoea est un grand genre complexe de 500–600 espèces de lianes et d’arbustes, largement réparti dans toutes les régions tropicales et subtropicales.

Plusieurs autres Ipomoea spp. présentes en Afrique de l’Ouest, ont des usages médicinaux.

Ipomoea argentaurata

Ipomoea argentaurata Hallier f. est une plante herbacée annuelle poilue à feuilles lancéolées et à fleurs rose pâle avec un centre foncé ; il est présent dans toute l’Afrique de l’Ouest à l’exception des parties les plus humides, jusqu’en Centrafrique et au Gabon. En Côte d’Ivoire, on boit la décoction des parties aériennes, en mangeant les noix de cola, pour améliorer la spermatogenèse. Au Bénin, la décoction de feuilles, en combinaison avec les feuilles de Ficus vallis-choudae Delile, se boit pour traiter l’hyperthermie. La décoction de rameaux feuillés se prend pour soigner le kwashiorkor.

Ipomoea dichroa

Ipomoea dichroa Hochst. ex Choisy est une plante herbacée volubile annuelle poilue à petites fleurs violettes, qui est répandue en Afrique de l’Ouest, dans certaines parties de l’Afrique de l’Est et de l’Afrique australe, et aussi en Inde. Au Nigeria, les feuilles séchées réduites en poudre s’appliquent sur les brûlures. Les graines, en combinaison avec celles d’Hibiscus sabdariffa L., se prennent comme purgatif. Les racines épaissies servent d’amulette d’amour. La plante est broutée par le bétail dans toute l’Afrique de l’Ouest.

Ipomoea hederacea

Ipomoea hederacea Jacq. (“Mexican morning glory”) est une plante herbacée vivace à fleurs bleu pâle, originaire de l’Amérique tropicale, mais il s’est répandu vers l’Europe, l’Afrique du Nord et l’Afrique tropicale, et vers certaines parties de l’Asie et de l’Australie. En Afrique tropicale, il est présent au Bénin, au Nigeria, en Ethiopie et au Soudan, mais probablement aussi ailleurs. Au Soudan, les graines grillées et réduites en poudre sont mélangées avec du yaourt et absorbées comme purgatif.

Ipomoea turbinata

Ipomoea turbinata Lag. (synonyme : Ipomoea muricata (L.) Jacq. non Cav.) est normalement une plante grimpante annuelle, originaire de l’Amérique centrale, mais largement naturalisée dans les régions tropicales et subtropicales, y compris dans les savanes herbeuses et les ripisylves en Afrique tropicale. Ses graines s’utilisent par endroits en Afrique de l’Ouest comme laxatif et succédané du café, mais aux Philippines les graines, les tiges et les feuilles ont été utilisées en médecine traditionnelle pendant des générations, notamment pour soigner le mal d’oreille, la pharyngite, la dermatite allergique, les plaies et les brûlures, ainsi que comme antidote contre l’empoisonnement. Des essais ont montré que l’extrait des graines a des propriétés analgésiques, antibactériennes et antifongiques. Ipomoea turbinata est aussi planté comme ornemental, mais dans certaines régions il est connu comme une adventice nuisible.

Croissance et développement

Dans des conditions environnementales contrôlées, Ipomoea asarifolia a produit des feuilles caractérisées par une matière sèche et une superficie foliaire élevées par rapport à la matière sèche totale de la plante dans des conditions d’illumination réduite. Dans des conditions d’illumination élevée, le taux de croissance a d’abord augmenté, puis il a plafonné. On peut trouver Ipomoea asarifolia en fleurs aussi longtemps qu’il y a assez d’eau.

Ecologie

Ipomoea asarifolia est une plante commune sur les sols hydromorphes, dans les zones basses des vallées à l’intérieur des terres ou le long des cours d’eau et sur les berges de rivières. Il est parfois adventice.

Multiplication et plantation

Ipomoea asarifolia se multiplie dans la nature par graines et par morceaux de tige. Dans un essai au Brésil pour étudier les taux de survie des graines des plantes adventices, le taux de survie des graines d’Ipomoea asarifolia était trop bas pour permettre une augmentation de leur nombre dans la banque de graines du sol. La scarification mécanique des graines a augmenté le taux de germination jusqu’à 100% au bout de 3 jours. La scarification chimique n’avait qu’un effet limité. La germination ne dépendait pas d’une exposition à la lumière.

Maladies et ravageurs

En Amérique du Sud, Ipomoea asarifolia est attaqué par des chrysomèles (Stolas sp.). La chrysomèle est fortement parasitée par la guêpe Emersonella neveipes, qui est aussi un parasite sur Chelymorpha cassidea, un ravageur de la patate douce.

Ressources génétiques

Ipomoea asarifolia est répandu et commun et n’est pas menacé d’érosion génétique.

Perspectives

Ipomoea asarifolia gardera son importance en phytothérapie, bien que davantage de recherches s’imposent afin d’identifier les composés responsables pour les activités et leur pharmacologie. La symbiose avec un champignon toxique requiert plus d’études toxicologiques, ainsi que des méthodes pour nettoyer les parties aériennes avant qu’on les utilise comme médicament.

Références principales

  • Austin, D.F., 2005. The enigmatic 'salsa da rua' - Ipomoea asarifolia (Convolvulaceae). Ethnobotany 17(1/2): 41–48.
  • Baerts, M. & Lehmann, J., 2012. Ipomoea repens. [Internet] Prelude Medicinal Plants Database. Metafro-Infosys, Royal Museum for Central Africa, Tervuren, Belgium http://www.metafro.be/prelude. Accessed December 2012.
  • Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
  • Farida, T., Salawu, O.A., Tijani, A.Y. & Ejiofor, J.I., 2012. Pharmacological evaluation of Ipomoea asarifolia (Desr.) against carbon tetrachloride-induced hepatotoxicity in rats. Journal of Ethnopharmacology 142(3): 642–646.
  • Gonçalves, M.L., 1987. Convolvulaceae. In: Launert, E. (Editor). Flora Zambesiaca. Volume 8, part 1. Flora Zambesiaca Managing Committee, London, United Kingdom. pp. 9–129.
  • Lawal, U., Ibrahim, H., Agunu, A. & Abdulahi, Y., 2010. Anti-inflammatory and analgesic activity of water extract from Ipomoea asarifolia Desr (Convolvulaceae). African Journal of Biotechnology 9(51): 8877–8880.
  • Meira, M, Pereira da Silva, E., David, J.M. & David, J.P., 2012. Review of the genus Ipomoea: traditional uses, chemistry and biological activities. Revista Brasileira de Farmacognosia 22(3): 682–713.
  • Markert, A., Steffan, N., Ploss, K., Hellwig, S., Steiner, U, Drewke, C., Li, S.M., Boland, W. & Leistner, E., 2008. Biosynthesis and accumulation of ergoline alkaloids in a mutualistic association between Ipomoea asarifolia (Convolvulaceae) and a clavicipitalean fungus. Plant Physiology 147(1): 296–305.
  • Medeiros, R.M.T., Barbosa, R.C., Riet-Correa, F., Lima, E.F., Tabosa, I.M., Barros, S.S., De Gardner, D.R. & Molyneux, R.J., 2003. Tremorgenic syndrome in goats caused by Ipomoea asarifolia in northeastern Brazil. Toxicon 41: 933–935.
  • Salles, H.O., Vasconcelos, I.M., Santos, L.F.L., Oliveira, H.D., Costa, P.P.C., Nascimento, N.R.F., Santos, C.F., Sousa, D.F., Jorge, A.R.C., Menezes, D.B., Monteiro, H.S.A., Gondim, D.M.F. & Oliveira, J.T.A., 2011. Towards a better understanding of Ipomoea asarifolia toxicity: Evidence of the involvement of a leaf lectin. Toxicon 58: 502–508.

Autres références

  • Achigan-Dako, E.G., Pasquini, M.W., Assogba-Komlan, F., N’danikou, S., Yédomonhan, H., Dansi, A. & Ambrose-Oji, B., 2010. Traditional vegetables in Benin: diversity, distribution, ecology, agronomy, and utilisation. Institut National des Recherches Agricoles du Bénin, Benin. 252 pp.
  • Agaie, B.M., Salisu, A. & Ebbo, A.A., 2007. A survey of common toxic plants of livestock in Sokoto State, Nigeria. Scientific Research and Essays 2(2): 40–42.
  • Dias Filho, M.B., 1999. Potential for seed bank formation of two weed species from Brazilian Amazonia. Planta Daninha 17(2): 183–188.
  • Ekenyem, B.U., 2006. An assessment of Ipomoea asarifolia leaf meal as feed ingredient in grower pig diet. Pakistan Journal of Nutrition 5(1): 39–42.
  • Ekenyem, B.U. & Madubuike, F.N., 2006. An assessment of Ipomoea asarifolia leaf meal as feed ingredient in broiler chick production. Pakistan Journal of Nutrition 5(1): 46–50.
  • Ekpa, O.D., 1996. Nutrient composition of three Nigerian medicinal plants. Food Chemistry 57(2): 229–232.
  • Feitosa, C.M., Freitas, R.M., Luz, N.N.N.., Bezerra, M.Z.B. & Trevisan, M.T.S., 2011. Acetylcholinesterase inhibition by some promising Brazilian medicinal plants. Brazilian Journal of Biology 71(3): 783–789.
  • Heine, H., 1963. Convolvulaceae. In: Hepper, F.N. (Editor). Flora of West Tropical Africa. Volume 2. 2nd Edition. Crown Agents for Oversea Governments and Administrations, London, United Kingdom. pp. 335–352.
  • Jegede, I.A., Nwinyi, F.C., Ibrahim, J., Ugbabe, G., Dzarma, S. & Kunle, O.F., 2009. Investigation of phytochemical, anti inflammatory and anti nociceptive properties of Ipomoea asarifolia leaves. Journal of Medicinal Plants Research 3(3): 160–165.
  • Kucht, S., Gross, J., Hussein, Y., Grothe, T., Keller, U., Basar, S., Konig, W. A., Steiner, U., & Leistner, E., 2004. Elimination of ergoline alkaloids following treatment of Ipomoea asarifolia (Convolvulaceae) with fungicides. Planta 219(4): 619–625.
  • Pale, E., Kouda Bonafos, M., Nacro, M., Vanhaelen, M. & Vanhaelen-Fastre, R., 2003. Two triacylated and tetraglucosylated anthocyanins from Ipomoea asarifolia flowers. Phytochemistry 64(8): 1395–1399.

Afriref references

Sources de l’illustration

  • Andrews, F.W., 1956. The flowering plants of the Anglo-Egyptian Sudan, Volume 3. Buncle, Arbroath, United Kingdom. 579 pp.

Auteur(s)

  • D.E. Tsala, Department of Life and Earth Sciences, Higher Teachers’ Training College, University of Maroua I, P.O. Box 55, Maroua, Cameroon

Citation correcte de cet article

Tsala, D.E., 2013. Ipomoea asarifolia (Desr.) Roem. & Schult. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editeurs). Prota 11(2): Medicinal plants/Plantes médicinales 2. PROTA, Wageningen, Pays Bas. Consulté le 1 mars 2018.

  • Voir cette page sur la base de données Prota4U
répartition en Afrique (sauvage)
1, partie de tige avec fruits ; 2, tige en fleurs et en fruits ; 3, fleur. Redessiné et adapté par J.M. de Vries

For musical instrument sometimes called a “sweet potato”, see Ocarina.

The sweet potato (Ipomoea batatas) is a dicotyledonous plant that belongs to the bindweed or morning glory family, Convolvulaceae. Its large, starchy, sweet-tasting, tuberous roots are a root vegetable.[1][2] The young leaves and shoots are sometimes eaten as greens. The sweet potato is only distantly related to the potato (Solanum tuberosum) and does not belong to the nightshade family, Solanaceae, but both families belong to the same taxonomic order, the Solanales.

The plant is a herbaceousperennialvine, bearing alternate heart-shaped or palmately lobed leaves and medium-sized sympetalousflowers. The edible tuberous root is long and tapered, with a smooth skin whose color ranges between yellow, orange, red, brown, purple, and beige. Its flesh ranges from beige through white, red, pink, violet, yellow, orange, and purple. Sweet potato cultivars with white or pale yellow flesh are less sweet and moist than those with red, pink or orange flesh.[3]

Ipomoea batatas is native to the tropical regions in the Americas.[4][5] Of the approximately 50 genera and more than 1,000 species of Convolvulaceae, I. batatas is the only crop plant of major importance—some others are used locally (e.g. I. aquatica "kangkong"), but many are poisonous. The genus Ipomoea that contains the sweet potato also includes several garden flowers called morning glories, though that term is not usually extended to Ipomoea batatas. Some cultivars of Ipomoea batatas are grown as ornamental plants under the name tuberous morning glory, used in a horticultural context.

Naming[edit]

See also: List of sweet potato cultivars

Although the soft, orange sweet potato is often called a "yam" in parts of North America, the sweet potato is botanically very distinct from a genuine yam (Dioscorea), which is native to Africa and Asia and belongs to the monocot family Dioscoreaceae. To add to the confusion, a different crop plant, the oca (Oxalis tuberosa, a species of wood sorrel), is called a "yam" in many parts of Polynesia, including New Zealand.

Although the sweet potato is not closely related botanically to the common potato, they have a shared etymology. The first Europeans to taste sweet potatoes were members of Christopher Columbus's expedition in 1492. Later explorers found many cultivars under an assortment of local names, but the name which stayed was the indigenous Taino name of batata. The Spanish combined this with the Quechua word for potato, papa, to create the word patata for the common potato.

In Argentina, Venezuela, Puerto Rico and the Dominican Republic the sweet potato is called batata. In Mexico, Peru, Chile, Central America, and the Philippines, the sweet potato is known as camote (alternatively spelled kamote in the Philippines), derived from the Nahuatl word camotli.[6]

In Peru, the Quechua name for a type of sweet potato is kumar, strikingly similar to the Polynesian name kumara and its regional Oceanic cognates (kumala, umala,  'uala, etc.), which has led some scholars to suspect an instance of pre-Columbian trans-oceanic contact.

In New Zealand, the most common cultivar is the red (purple) cultivar called kumara, a name derived from the Māori name kūmara, but orange ('Beauregard') and gold cultivars are also available.[7] Kumara is particularly popular as a roasted food, or in contemporary cuisine as kumara chips, often served with sour cream and sweet chili sauce. Occasionally, shops in Australia will label purple cultivars as "purple sweet potato" to denote the difference to the other cultivars. About 95% of Australia's production is of the orange cultivar named 'Beauregard', originally from North America, known simply as "sweet potato". A reddish-purple cultivar, 'Northern Star', is 4% of production and is sold as "kumara".

Origin, distribution and diversity[edit]

The origin and domestication of sweet potato is thought to be in either Central America or South America.[8] In Central America, sweet potatoes were domesticated at least 5,000 years ago.[9] In South America, Peruvian sweet potato remnants dating as far back as 8000 BC have been found.

One author postulated that the origin of I. batatas was between the Yucatán Peninsula of Mexico and the mouth of the Orinoco River in Venezuela.[10] The cultigen had most likely been spread by local people to the Caribbean and South America by 2500 BC.[11] Strong supporting evidence was provided that the geographical zone postulated by Austin is the primary center of diversity.[10] The much lower molecular diversity found in Peru–Ecuador suggests this region should be considered as a secondary center of sweet potato diversity.

The sweet potato was grown in Polynesia before western exploration. Sweet potato has been radiocarbon-dated in the Cook Islands to 1000 AD, and current thinking is that it was brought to central Polynesia around 700 AD, possibly by Polynesians who had traveled to South America and back, and spread across Polynesia to Hawaii and New Zealand from there.[12][13] It is possible, however, that South Americans brought it to the Pacific, although this is unlikely as it was the Polynesians, and not the native South Americans, who had a strong maritime tradition. The theory that the plant could spread by floating seeds across the ocean is not supported by evidence. Another point is that the sweet potato in Polynesia is the cultivated Ipomoea batatas, which is generally spread by vine cuttings and not by seeds.[14]

Sweet potatoes are cultivated throughout tropical and warm temperate regions wherever there is sufficient water to support their growth.[15] Due to a major crop failure, sweet potatoes were introduced to Fujian province of China in about 1594 from Luzon. The growing of sweet potatoes was encouraged by the Governor Chin Hsüeh-tseng (Jin Xuezeng).[16][17] Sweet potatoes were introduced as a food crop in Japan, and by 1735 were planted in Shogun Tokugawa Yoshimune's private garden.[18] It was also introduced to Korea in 1764.[19]

Sweet potatoes became popular very early in the islands of the Pacific Ocean, spreading from Polynesia to Japan and the Philippines. One reason[original research?] is that they were a reliable crop in cases of crop failure of other staple foods because of typhoon flooding. They are featured in many favorite dishes across Asia and North America. Sweet potato, also known as kelang in Tulu, is part of Udupi cuisine in South India. Uganda (the second largest grower after China), Rwanda, and some other African countries also grow a large crop which is an important part of their peoples' diets. The New World, the original home of the sweet potato, grows less than three percent (3%) of the world's supply. Europe has only a very small sweet potato production, mainly in Portugal. In the Caribbean, a cultivar of the sweet potato called the boniato is popular. The flesh of the boniato is cream-colored, unlike the more popular orange hue seen in other cultivars. Boniatos are not as sweet and moist as other sweet potatoes, but many people prefer their fluffier consistency and more delicate flavor.

Sweet potatoes have been an important part of the diet in the United States for most of its history, especially in the Southeast. From the middle of the 20th century, however, they have become less popular. The average per capita consumption of sweet potatoes in the United States is only about 1.5–2 kg (3.3–4.4 lb) per year, down from 13 kg (29 lb) in 1920. Southerner Kent Wrench writes: "The Sweet Potato became associated with hard times in the minds of our ancestors and when they became affluent enough to change their menu, the potato was served less often."[20]

Transgenicity[edit]

A study published in 2015 by scientists from Ghent University and the International Potato Center found that the genome of cultivated sweet potatoes contains sequences of DNA from Agrobacterium, with genes being actively expressed by the plants. The discovery of the transgenes was made while performing metagenomic analysis of the sweet potato genome for viral diseases. Transgenes were observed both in the sweet potato's closely related wild relatives, and also were found in more distantly related wild species. This observation makes cultivated sweet potatoes the first known example of a naturally transgenic food crop.[21][22]

Cultivation[edit]

Producers (in million tonnes)[23]
Data for year 2011
China81.7
Uganda2.8
Nigeria2.8
Indonesia2.0
Tanzania1.4
Vietnam1.3
India1.1
United States1.0
World106.5

The plant does not tolerate frost. It grows best at an average temperature of 24 °C (75 °F), abundant sunshine and warm nights. Annual rainfalls of 750–1,000 mm (30–39 in) are considered most suitable, with a minimum of 500 mm (20 in) in the growing season. The crop is sensitive to drought at the tuber initiation stage 50–60 days after planting, and it is not tolerant to water-logging, as it may cause tuber rots and reduce growth of storage roots if aeration is poor.[24]

Depending on the cultivar and conditions, tuberous roots mature in two to nine months. With care, early-maturing cultivars can be grown as an annual summer crop in temperate areas, such as the northern United States and China. Sweet potatoes rarely flower when the daylight is longer than 11 hours, as is normal outside of the tropics. They are mostly propagated by stem or root cuttings or by adventitious shoots called "slips" that grow out from the tuberous roots during storage. True seeds are used for breeding only.

They grow well in many farming conditions and have few natural enemies; pesticides are rarely needed. Sweet potatoes are grown on a variety of soils, but well-drained, light- and medium-textured soils with a pH range of 4.5-7.0 are more favorable for the plant.[2] They can be grown in poor soils with little fertilizer. However, sweet potatoes are very sensitive to aluminum toxicity and will die about six weeks after planting if lime is not applied at planting in this type of soil.[2] Because they are sown by vine cuttings rather than seeds, sweet potatoes are relatively easy to plant. Because the rapidly growing vines shade out weeds, little weeding is needed. A commonly used herbicide to rid the soil of any unwelcome plants that may interfere with growth is DCPA, also known as Dacthal. In the tropics, the crop can be maintained in the ground and harvested as needed for market or home consumption. In temperate regions, sweet potatoes are most often grown on larger farms and are harvested before first frosts.

In the Southeastern United States, sweet potatoes are traditionally cured to improve storage, flavor, and nutrition, and to allow wounds on the periderm of the harvested root to heal.[20] Proper curing requires drying the freshly dug roots on the ground for two to three hours, then storage at 29–32 °C (85–90 °F) with 90 to 95% relative humidity from five to fourteen days. Cured sweet potatoes can keep for thirteen months when stored at 13–15 °C (55–59 °F) with >90% relative humidity. Colder temperatures injure the roots.[25][26]

Main article: Sweet potato storage

Yields[edit]

In 2010, the world average annual yield for sweet potato crop was 13.2 tonnes per hectare. The most productive farms of sweet potato breeds were in Senegal, where the nationwide average annual yield was 33.3 tonnes per hectare.[27] Yields as high as 80 metric tonnes per hectare have been reported from farms of Israel.[28]

Diseases[edit]

Main article: List of sweet potato diseases

Production[edit]

According to the Food and Agriculture Organization (FAO) statistics, world production in 2004 was 127 million tonnes.[29] The majority comes from China, with a production of 105 million tonnes from 49,000 km2 (19,000 sq mi). About half of the Chinese crop is used for livestock feed.[9]

Per capita production is greatest in countries where sweet potatoes are a staple of human consumption, led by Papua New Guinea at about 500 kg (1,100 lb)[30] per person per year, the Solomon Islands at 160 kg (350 lb), Burundi and Rwanda[31] at 130 kg (290 lb) and Uganda at 100 kg (220 lb).

About 20,000 tonnes of sweet potatoes are produced annually in New Zealand, where sweet potato is known by its Māori name, kūmara. It was a staple food for Māori before European contact.[32]

In the United States, North Carolina, the leading state in sweet potato production, provided 38.5% of the 2007 U.S. production of sweet potatoes. In 2007, California produced 23%, Louisiana 15.9%, and Mississippi 19% of the U.S. total.[33][34]

Mississippi has about 150 farmers growing sweet potatoes on about 8,200 acres (30 km2), contributing $19 million to the state's economy. Mississippi's top five sweet-potato-producing counties are Calhoun, Chickasaw, Pontotoc, Yalobusha, and Panola. The National Sweet Potato Festival is held annually the entire first week in November in Vardaman (Calhoun County), which proclaims itself as "The Sweet Potato Capital".

Nutrient content[edit]

Besides simple starches, raw sweet potatoes are rich in complex carbohydrates, dietary fiber and beta-carotene (a provitamin Acarotenoid), while having moderate contents of other micronutrients, including vitamin B5, vitamin B6 and manganese (table).[35] When cooked by baking, small variable changes in micronutrient density occur to include a higher content of vitamin C at 24% of the Daily Value per 100 g serving (right table).[36][37]

The Center for Science in the Public Interest ranked the nutritional value of sweet potatoes as highest among several other foods.[38]

Sweet potato cultivars with dark orange flesh have more beta-carotene than those with light-colored flesh, and their increased cultivation is being encouraged in Africa where vitamin A deficiency is a serious health problem. A 2012 study of 10,000 households in Uganda found that children eating beta-carotene enriched sweet potatoes suffered less vitamin A deficiency than those not consuming as much beta-carotene.[39]

Comparison to other food staples[edit]

The table below presents the relative performance of sweet potato to other staple foods. While sweet potato provides less edible energy and protein per unit weight than cereals, it has higher nutrient density than cereals.[40]

According to a study by the United NationsFood and Agriculture Organization, sweet potatoes are the most efficient staple food to grow in terms of farmland, yielding approximately 70,000 kcal/had.[41]

Nutrient component:Maize / Corn[A]Rice (white)[B]Rice (brown)[I]Wheat[C]Potato[D]Cassava[E]Soybean (Green)[F]Sweet potato[G]Yam[Y]Sorghum[H]Plantain[Z]RDA
Water (g)1012101379606877709653000
Energy (kJ)152815281549136932267061536049414195118368–10,460
Protein (g)9.47.17.912.62.01.413.01.61.511.31.350
Fat (g)4.740.662.921.540.090.286.80.050.173.30.37
Carbohydrates (g)7480777117381120287532130
Fiber (g)7.31.33.512.22.21.84.234.16.32.330
Sugar (g)0.640.120.850.410.781.704.180.5015
Calcium (mg)7282329121619730172831000
Iron (mg)2.710.81.473.190.780.273.550.610.544.40.68
Magnesium (mg)127251431262321652521037400
Phosphorus (mg)2101153332885727194475528734700
Potassium (mg)2871152233634212716203378163504994700
Sodium (mg)3557261415559641500
Zinc (mg)2.211.092.022.650.290.340.990.30.2400.1411
Copper (mg)0.310.220.430.110.100.130.150.18-0.080.9
Manganese (mg)0.491.093.743.990.150.380.550.260.40--2.3
Selenium (μg)15.515.170.70.30.71.50.60.701.555
Vitamin C (mg)000019.720.6292.417.1018.490
Thiamin (B1)(mg)0.390.070.400.300.080.090.440.080.110.240.051.2
Riboflavin (B2)(mg)0.200.050.090.120.030.050.180.060.030.140.051.3
Niacin (B3) (mg)3.631.65.095.461.050.851.650.560.552.930.6916
Pantothenic acid (B5) (mg)0.421.011.490.950.300.110.150.800.31-0.265
Vitamin B6 (mg)0.620.160.510.30.300.090.070.210.29-0.301.3
Folate Total (B9) (μg)198203816271651123022400
Vitamin A (IU)21400921318014187138011275000
Vitamin E, alpha-tocopherol (mg)0.490.110.591.010.010.1900.260.3900.1415
Vitamin K1 (μg)0.30.11.91.91.91.901.82.600.7120
Beta-carotene (μg)9705180850983045710,500
Lutein+zeaxanthin (μg)1355022080000030
Saturated fatty acids (g)0.670.180.580.260.030.070.790.020.040.460.14
Monounsaturated fatty acids (g)1.250.211.050.20.000.081.280.000.010.990.03
Polyunsaturated fatty acids (g)2.160.181.040.630.040.053.200.010.081.370.07
A yellow cornB raw unenriched long-grain white rice
C hard red winter wheatD raw potato with flesh and skin
E raw cassavaF raw green soybeans
G raw sweet potatoH raw sorghum
Y raw yamZ raw plantains
I raw long-grain brown rice

Culinary uses[edit]

Although the leaves and shoots are also edible, the starchy tuberous roots are by far the most important product. In some tropical areas, they are a staple food crop.

Africa[edit]

Amukeke (sun-dried slices of root) and inginyo (sun-dried crushed root) are a staple food for people in northeastern Uganda.[43]Amukeke is mainly served for breakfast, eaten with peanut sauce. Inginyo is mixed with cassava flour and tamarind to make atapa. People eat atapa with smoked fish cooked in peanut sauce or with dried cowpea leaves cooked in peanut sauce. Emukaru (earth-baked root) is eaten as a snack anytime and is mostly served with tea or with peanut sauce. Similar uses are also found in South Sudan.

The young leaves and vine tips of sweet potato leaves are widely consumed as a vegetable in West African countries (Guinea, Sierra Leone and Liberia, for example), as well as in northeastern Uganda, East Africa.[43] According to FAO leaflet No. 13 - 1990, sweet potato leaves and shoots are a good source of vitamins A, C, and B2 (riboflavin), and according to research done by A. Khachatryan, are an excellent source of lutein.

In Kenya, Rhoda Nungo of the home economics department of the Ministry of Agriculture has written a guide to using sweet potatoes in modern recipes.[44] This includes uses both in the mashed form and as flour from the dried tubers to replace part of the wheat flour and sugar in baked products such as cakes, chapatis, mandazis, bread, buns and cookies. A nutritious juice drink is made from the orange-fleshed cultivars, and deep-fried snacks are also included.

In Egypt, sweet potato tubers are known as "batata" (بطاطا) and are a common street food in winter, when street vendors with carts fitted with ovens sell them to people passing time by the Nile or the sea. The cultivars used are an orange-fleshed one as well as a white/cream-fleshed one. They are also baked at home as a snack or dessert, drenched with honey.

In Ethiopia, the commonly found cultivars are black-skinned, cream-fleshed and called "bitatis" or "mitatis". They are cultivated in the eastern and southern lower highlands and harvested during the rainy season (June/July). In recent years, better yielding orange-fleshed cultivars were released for cultivation by Haramaya University as a less sugary sweet potato with higher vitamin A content.[45] Sweet potatoes are widely eaten boiled as a favored snack providing calories and carbohydrates.

Asia[edit]

Further information: roasted sweet potato and sweet potato soup

In East Asia, roasted sweet potatoes are popular street food. In China, sweet potatoes, typically yellow cultivars, are baked in a large iron drum and sold as street food during winter. In Korea, sweet potatoes, known as goguma, are roasted in a drum can, baked in foil or on an open fire, typically during winter. In Japan, a dish similar to the Korean preparation is called yaki-imo (roasted sweet potato), which typically uses either the yellow-fleshed "Japanese sweet potato" or the purple-fleshed "Okinawan sweet potato", which is known as beni-imo.

Sweet potato soup, served during winter, consists of boiling sweet potato in water with rock sugar and ginger. Sweet potato greens are a common side dish in Taiwanese cuisine, often boiled or sautéed and served with a garlic and soy sauce mixture, or simply salted before serving. They, as well as dishes featuring the sweet potato root, are commonly found at bento (Pe̍h-ōe-jī: piān-tong) restaurants. In northeastern Chinese cuisine, sweet potatoes are often cut into chunks and fried, before being drenched into a pan of boiling syrup.[46]

In some regions of India, sweet potato is roasted slow over kitchen coals at night and eaten with some dressing while the easier way in the south is simply boiling or pressure cooking before peeling, cubing and seasoning for a vegetable dish as part of the meal. In Indian state of Tamil Nadu, it is known as 'Sakkara valli Kilangu'. It is boiled and consumed as evening snack. In some parts of India, fresh sweet potato is chipped, dried and then ground into flour; this is then mixed with wheat flour and baked into chapattis (bread). Between 15 and 20 percent of sweet potato harvest is converted by some Indian communities into pickles and snack chips. A part of the tuber harvest is used in India as cattle fodder.[3]

In Pakistan, sweet potato is known as shakarqandi and is cooked as vegetable dish and also with meat dishes (chicken, mutton or beef). The ash roasted sweet potatoes are sold as a snack and street food in Pakistani bazaars especially during the winter months.[47]

In Sri Lanka, it is called 'Bathala' and tubers are used mainly for breakfast (boiled sweet potato commonly with sambal or grated coconut) or as an supplementary curry dish for rice. There are many other culinary uses with sweet potato as well.

The tubers of this plant, known as kattala in Dhivehi, have been used in the traditional diet of the Maldives. The leaves were finely chopped and used in dishes such as mas huni.[48]

In Japan, both sweet potatoes (called "satsuma-imo") and true purple yams (called "daijo" or "beni-imo") are grown. Boiling and steaming are the most common cooking methods. Also, the use in vegetable tempura is common. Daigaku-imo is a baked sweet potato dessert. Because it is sweet and starchy, it is used in imo-kinton and some other traditional sweets, such as ofukuimo. Shōchū, a Japanese spirit normally made from the fermentation of rice, can also be made from sweet potato, in which case it is called imo-jōchū. Imo-gohan, sweet potato cooked with rice, is popular in Guangdong, Taiwan and Japan. It is also served in nimono or nitsuke, boiled and typically flavored with soy sauce, mirin and dashi. In Korean cuisine, sweet potato starch is used to produce dangmyeon (cellophane noodles). Sweet potatoes are also boiled, steamed, or roasted, and young stems are eaten as namul. Pizza restaurants such as Pizza Hut and Domino's in Korea are using sweet potatoes as a popular topping. Sweet potatoes are also used in the distillation of a variety of Soju.

In Malaysia and Singapore, sweet potato is often cut into small cubes and cooked with yam and coconut milk (santan) to make a sweet dessert called bubur caca or "bubu chacha". A favorite way of cooking sweet potato is deep frying slices of sweet potato in batter, and served as a tea-time snack. In homes, sweet potatoes are usually boiled. The leaves of sweet potatoes are usually stir-fried with only garlic or with sambal belacan and dried shrimp by Malaysians.

In the Philippines, sweet potatoes (locally known as camote or kamote) are an important food crop in rural areas. They are often a staple among impoverished families in provinces, as they are easier to cultivate and cost less than rice.[49] The tubers are boiled or baked in coals and may be dipped in sugar or syrup. Young leaves and shoots (locally known as talbos ng kamote or camote tops) are eaten fresh in salads with shrimp paste (bagoong alamang) or fish sauce. They can be cooked in vinegar and soy sauce and served with fried fish (a dish known as adobong talbos ng kamote), or with recipes such as sinigang.[49] The stew obtained from boiling camote tops is purple-colored, and is often mixed with lemon as juice. Sweet potatoes are also sold as street food in suburban and rural areas. Fried sweet potatoes coated with caramelized sugar and served in skewers (camote cue) are popular afternoon snacks.[50] Sweet potatoes are also used in a variant of halo-halo called ginatan, where they are cooked in coconut milk and sugar and mixed with a variety of rootcrops, sago, jackfruit and bilu-bilo (glutinous rice balls).[51] Bread made from sweet potato flour is also gaining popularity. Sweet potato is relatively easy to propagate, and in rural areas that can be seen abundantly at canals and dikes. The uncultivated plant is usually fed to pigs.

In Indonesia, sweet potatoes are locally known as ubi jalar (lit: spreading tuber) and are frequently fried with batter and served as snacks with spicy condiments, along with other kinds of fritters such as fried bananas, tempeh, tahu, breadfruits, or cassava. In the mountainous regions of West Papua, sweet potatoes are the staple food among the natives there. Using the bakar batu way of cooking (free translation: burning rocks), rocks that have been burned in a nearby bonfire are thrown into a pit lined with leaves. Layers of sweet potatoes, an assortment of vegetables, and pork are piled on top of the rocks. The top of the pile then is insulated with more leaves, creating a pressure of heat and steam inside which cooks all food within the pile after several hours.

Young sweet potato leaves are also used as baby food particularly in Southeast Asia and East Asia.[52][53] Mashed sweet potato tubers are used similarly throughout the world.[54]

North America[edit]

Candied sweet potatoes are a side dish consisting mainly of sweet potatoes prepared with brown sugar, marshmallows, maple syrup, molasses, orange juice, marron glacé, or other sweet ingredients. It is often served in America on Thanksgiving. Sweet potato casserole is a side dish of mashed sweet potatoes in a casserole dish, topped with a brown sugar and pecan topping.[55]Sweet potato pie

Sweet potatoes with different skin colors
Soft, orange-fleshed cultivar of sweet potato
Jjin-goguma (steamed sweet potatoes)

gungoguma, roasted sweet potatoes

"gungoguma drum" for roasting sweet potatoes

Goguma-mattang (candied sweet potatoes)
Tong sui, a sweet potato-based soup popular in China during winter.
Bottle and two cartons of Japanese sweet potato shōchū spirits.
Imomeigetsu, also known as Tsukimi, is a Japanese festival honoring the beauty of autumn moon. Sake and sweet potatoes are offered to the moon, with prayers for an abundant harvest. Dishes made of sweet potato are ubiquitous. Shown here is Tsukimi dango.
Camote tops, a Philippine salad made from young sweet potato leaves (talbos ng kamote)
Sweet potato fries with a vegetarian burger

0 Replies to “Ipomoea Asarifolia Descriptive Essay”

Lascia un Commento

L'indirizzo email non verrà pubblicato. I campi obbligatori sono contrassegnati *