Presentation on theme: "Starchy (non-grass) Staples -mostly root crops -mostly of tropical origin, though often temperate & tropical cultivation now -mostly propogated asexually."— Presentation transcript:
Starchy (non-grass) Staples -mostly root crops -mostly of tropical origin, though often temperate & tropical cultivation now -mostly propogated asexually -highly productive & often economically important -often among first plants used & domesticated by humans -often low in protein & oils
Starch: (from- Starch is a type of carbohydrate. Specifically, starch is a complex carbohydrate (polysaccharide) made from thousands of glucose units. Starch is the main compound that plants use to store their food energy. Starch is One of Three Types of Carbohydrates There are three basic types of carbs: (1) starchy carbohydrates (polysaccharides); (2) sugars (monosaccharides or disaccharides) and (3) dietary fiber (polysaccharides). Carbs are one of three main food nutrients: the others being protein and fat. Starch is a Plant Chemical Chemically speaking, starch is a white, odorless, tasteless, solid carbohydrate, typically composed of long chains of glucose molecules (1000 or more). The most common forms are amylose and amylopectin. Plants store the energy produced by photosynthesis in the form of starch. Starch is a Complex Carbohydrate Because the molecular structure of complex carbohydrates is more complicated than more simple carbohydrate sugars, like sucrose and glucose, the body cannot metabolize complex carbs into energy as quickly as simple carbs. Result? Complex carbs are not digested and turned into energy as fast as sugars and therefore keep us full for longer.
Starch (cont.) Starch is an Intermediate or High Glycemic Index Food However, the classification of carbs into "simple" or "complex carbs" has been superceded by the Glycemic Index, which rates carbs according to their effect on blood-glucose levels. Many starchy foods (eg. potatoes) are now classified as intermediate or high-glycemic-index foods and should (for best effects on blood- sugar and insulin sensitivity) be eaten in combination with lower glycemic index foods. Starch in Foods Starch is found in plant-based foods, especially cereals, bread, potatoes, legumes (beans), pasta and rice, which are all classified as "starchy carbohydrates." Starch is also found in some fruits, vegetables, and in the roots and stem pith of plants.
Starch continued Starch is made and stored in plastids: e.g., chloroplasts in leaves, and amyloplasts in roots. Salivary enzymes in humans begins the breakdown of starch in the mouth, giving a slightly sweet taste. In traditional diets, provides 85% of the total carbohydrates consumed; sugars only 15%. In socioeconomically rich countries, provides only 62% of the total carbohydrates consumed and sugars provide 38%.
Starch makes a stand USA Today.com 25 Feb 2004 Potatoes, pasta, rice and bread-once the high-carb heroes of dieters and marathon runners – are being snubbed by consumers caught up in the low- carbohydrate craze Potato: 100 calories for 1 medium size, 45% RDA Vitamin C; 21% Calcium ‘good’ carbohydrates: nutrient-rich complex ones, found in plant food such as fruits, vegetables, whole grains, beans ‘bad’ carbohydrates: highly processed & refined foods ‘most of the world bases their diets on carbohydrates, and they don’t have the obesity rates we do because they eat less & exercise more’
*** A major raw material for industrial starch ** A raw material for industrial production in confined areas * A crop with potential but limited use as a raw material for starch Important starchy foods: (International Starch Institute, Denmark; Amaranth* Arrow Root** Banana* Barley** Cassava*** Maize*** Millet** Oat** Potato*** Rice** Rye Sago** Sorghum** Sweet Potato** Wheat*** Yam*
Modified stems and roots Stems –Stolons or runners horizontal stems, long internodes, found above ground –Rhizome horizontal underground stems –Bulb vertical underground stem; food reserves in leaves –Corm vertical underground stem; store food reserved in stem Storage Roots –Tuber enlarged storage tips of rhizome –Tuberous root fleshy fibrous roots, enlarged with food reserves –Taproot biennial plants
“Potatoes” White, Sweet, and Yams Each a different species in a different family –White = Solanum tuberosum; Solonaceae –Sweet = Ipomoea batatas; Convolvulaceae –Yam = Dioscorea species; Dioscoreaceae
(White) POTATO “ scarcely innocent underground stem of one of a tribe set aside for evil” “ could be used for exciting Venus” “could cause leprosy” “the English or Irish potato increaseth thy seed and provoketh lust in both sexes”
“Potatoes are for peasants” Nobles/wealthy wanted peasants to eat potatoes and save wheat for nobility & export Easy to to cultivate Matures in 4 months High production Easy to prepare (just boil)
Solanaceae (Nightshade or Potato family) simple, alternate leaves flowers are 5-mers sepals and petals fused into a tube fruit a berry or capsule 85 genera, ca species includes tomato, potato, tobacco, eggplant, nightshade, carolina horse nettle, mandrake, henbane
Market in Peru: farmers in the Andes cultivate up to 3,000 potato varieties.
The white potato Tuber crop Eye = buds located at the nodes; each bud can give rise to a new plant Origin = Andean highlands of S. America Ca years ago Staple of Incas Introduced to Europe ca Biggest producers are N. Europe & China
White potato continued U.S. crop mostly from Idaho, Washington, & Maine; but planted widely; 50% used for french fries & chips >6000 cultivars of white potato known (12 make up most of U.S. crop) Herbaceous annual Cool-season crop Only the tuber is non-toxic GM versions rare Four common types: round white, russet, round red, long white High in CHO (ca. 25% FW); low in protein (2.5%), but it’s high quality; little fat; lots of vitamins & minerals & fiber
Late blight in potato Introduced into Europe (Isle of Wight) in 1625 from Americas Became most important in Ireland; allowed for population explosion; but most of Ireland (the poor) relied very heavily on it for food Major potato pathogen in Ireland is a fungus, Phytophthora infestans In Ireland, major epidemics in : island-wide potato failure Control measures known at that time: plant only every 6th year, use clean seed tubers not connected to diseased field; do not feed diseased tubers to stock w/o boiling Ireland = agricultural colony of Great Britain absentee (foreign, English) landlords - Irish serfs potato = major staple; wheat = export crop to England no major industries: elimination of competition with GB; high unemployment 9 million people before epidemic; 1 million deaths from starvation, diseases (cholera, typhus, etc.) 1.5 million emigrants after epidemic; 5.5 million emigrants until WWI, many to U.S. East Coast (e.g., Boston) The Potato: a cautionary tale
Seeds of Change By Henry Hobhouse “Five plants that transformed mankind” Chapters on: quinine, sugar, tea, cotton, potato Interesting, informative, historical
Botany of Desire By Michael Pollan –4 desires: sweetness, beauty, intoxication, control –history of people manipulating plants - or is it a history of plants manipulating people? –focus on four plants: apples, tulips, marijuana, & potatoes
Sweet potato Species: Ipomoea batatas (L.) Lam. Family: Convolvulaceae Tropical perennial (from S. America) cultivated as an annual in temperate climates Enlarged edible storage (tuberous) roots; lots of beta-carotene & sweet taste 80% of world production in China, U.S. accounts for 1% of production Two types –Cream-to-light yellow colored flesh, non-sweet flavor, dry texture –Yellow or deep orange, moist texture, distinct flavor, high sugar content (often called “yams”)
Sweet potato continued Warm-season crop Introduced to Europe (Spain) by Columbus Rich in CHO (more sugar & calories, less starch, compared to white potato); rich in certain vitamins, especially A (from beta- carotene) & C
(true) Yams Dioscorea species; Dioscoreaceae (Yam family); a monocot Old World tropical origin (W. Africa) Tubers (up 90 lbs); hard to harvest, so mostly replaced by cassava ca. 20% starch; low in protein, vitamins (low in carotene too), & minerals Tubers contain saponins, type of steroid –Once used to make human sex hormones and cortisone
Several decades ago, when orange- fleshed sweet potatoes were introduced in the southern United States, producers and shippers desired to distinguish them from the more traditional, white-fleshed types. The African word nyami, referring to the starchy, edible root of the Dioscorea genus of plants, was adopted in its English form, yam. Yams in the U.S. are actually sweet potatoes with relatively moist texture and orange flesh. Although the terms are generally used interchangeably, the U.S. Department of Agriculture requires that the label "yam" always be accompanied by "sweet potato."
Taro “potato of the humid tropics” Poi, traditional dish of native Hawaiians Corms are steamed, crushed, made into a dough, and allowed to ferment naturally by microbes. Doughy paste eaten with fingers or rolled into small balls; main staple in the traditional diet. Can be cooked similar to potatoes (baked, steamed, roasted, boiled) or processed into flour, chips, breakfast foods
THE POTATO OF THE HUMID TROPICS Taro, dasheen, or cocoyam (Colocasia esculenta var. antiquorum) ARACEAE, Arum Family About 10% of the world's population uses taro or taro-like plants (Araceae) as a staple in the diet, and for 100 million people this is an important daily food. The Colocasia taro is a very common crop for wet soils in the humid tropics, especially in Southeast Asia, the Pacific Basin, wet tropical Africa and Egypt, the West Indies, and certain areas of South America; the yautias (Xanthosoma), close cousins of taro, are native to and grow mostly in the New World. The chief food from these plants is the "corm," an erect, starchy, underground stem, which grows to be over a foot long, but leaves are also consumed.taro Taro has leaves that are 1 to 2 meters long with a long, erect petiole and an arrow- shaped blade. Plants like this are sometimes called "elephant ear." The plants rarely flowers and never set seed, so vegetative propagation via replanting portions of the corm is the only way to grow this plant.leaves Some have speculated that taro and yautia were among the first of all cultivated plants, because natives learned to eat the bottom portion of the corm and then replant the leaves and top of the corm, so that they could return in ten months for a new crop. Estimates are that taro was in cultivation in wet tropical India before 5000 B.C.
When Captain Cook discovered the Hawaiian Islands in 1778, the native population (est. 300,000) lived chiefly on dasheen and sweet potatoes (Ipomoea batatas), supplemented with things from the sea. Poi was traditionally prepared by removing the corm "skin" and then pounding the white flesh on a board with a stone pounder (pohaku ku'I) to make a thick paste, which was dried, diluted with water, kneaded, and then aged. The infamous Polynesian poi may be fermented (first bacteria, then yeast) or sometimes unfermented forms of this sticky dasheen paste, eaten with the fingers or as small balls. Some Polynesians were said to consume up to 20 pounds of poi per day! Taro corms are roasted, boiled, or baked, and may be made into cakes. Heating is necessary to remove an acrid, irritating property of the raw corm. In the Hawaiian Islands, taro plant is eaten after thoroughly boiled to destroy the toxins; the leaf (luau, also the name of the feast using taro leaves) must be boiled at least 45 minutes over low heat, whereas corms are boiled in a deep pot with salted water for at least an hour or until soft. Taro is similar to the Irish potato (Solanum tuberosum) in many properties, and is sometimes called the "potato" of the humid tropics. In comparison with potato, taro corm has a similar proportion of protein ( %), calcium, and phosphorus; it has a trace of fat, and is rich in vitamins A and C. Moreover, taro is 98.8% digestible, because it has very small starch grains fairly rich in amylose (20-25%), which breaks down to sugar with human saliva. This type of carbohydrate is excellent for people with digestive problems, so that taro flour is used in infant formulae and canned baby foods and is good for people with allergies, such as lactose intolerance.
Manioc or Cassava Euphorbiaceae: Manihot esculenta starchy staple in tropics; e.g., Africa, S. America, Asia Originated from north S. America Other names: yuca, mandioca large herbaceous shrub up to 10 feet; with tuberous roots like large sweet potatoes in appearance Grown in warm climates fleshy roots contain poisonous compounds (cyanogenic glycosides - compounds that liberate cyanide) that must be removed before eating heat, drought, & pest tolerant; also tolerates acid & high- Al soil 30% FW starch; <1% protein
detoxification peeling and grating the flesh causes HCN production squeeze the contents and get the maximum surface area exposed to enzymes and to squeeze out some of the toxic leachate pulp stands overnight and the remaining toxins are removed by the heat of cooking the pulp or meal into cakes Other methods- –Sometimes drying in the sun is enough to remove the cyanide gas; it will disperse into the air as the manioc dries in the heat. sweet manioc is less toxic & can be merely boiled or baked, but is more pest & disease susceptible compared to more toxic bitter varieties purified starch for thickening agent –tapioca are gelatinized pellets
Banana Banana Musa species; Musaceae (banana family) Common Names: Banana, Bananier Nain, Canbur, Curro, Plantain Origin: SE Asia. Fruits (a berry): ovaries develop parthenocarpically (w/o pollination) into clusters of fruits, called hands. cultivated types are seedless with just vestiges of ovules visible as brown specks. Occasionally, cross-pollination with wild types will result in a number of seeds in a normally seedless variety. Propagated vegetatively, so genetic uniformity Both sweet & starchy (plantain) varieties Needs warm temps & lots of water; grown in tropics; A large herbaceous annual
New test speeds search for resistant bananas 12 March 2004 In recent years, Panama disease has had a major impact on banana yields in Africa, Asia and Australia, and is expected to spread to Latin America and the Caribbean. ….The fungus that causes the disease, known as Fusarium oxysporum, establishes itself in the soil and is virtually impossible to control with chemicals….The current method of detecting which banana strains are susceptible to the disease is time-consuming and laborious. It involves infecting soil with the fungus, waiting for the plant to grow, and then cutting the plant at the base of the stem to evaluate the extent of internal damage. …. The new test takes just a few days to get results, and can be carried out on a single leaf. The fungus is grown in the laboratory and applied to tiny perforations in harvested banana leaves. After 48 hours, lesions of around 18 mm in length can be seen in the leaves of susceptible plants, while leaves from resistant plants have much smaller lesions of less than 7 mm. …. Ninety nine per cent of bananas found in Western supermarkets belong to a single variety, Cavendish, a sterile clone that is propagated by cuttings. The variety was initially adopted in the 1960s, when Panama disease forced banana growers around the world to abandon previous varieties. But now Cavendish bananas are being infected with a new virulent strain of the fungus, called race 4, making it essential that new resistant strains are developed.
Jerusalem artichoke Helianthus tuberosus (Asteraceae) Pilgrims named this staple with regard to the “New Jerusalem” they were carving out of the wilderness Weedy hardy easily-cultivated perennial produces tubers 10% protein, 76% carbohydrate inulin, no oil, no starch –Inulin is digested into fructose, which is 1.5 x sweeter than sucrose –folk remedy of diabetes Eat fresh, cooked or pickled
Lotus (Nelumbo nucifera in Asia, N. lutea in N. America) Family Nymphaeaceae Water Lily family Lotus roots are good stir-fried or steamed; but they can also be boiled, baked, or braised –Chinese traditionally serve them candied as a New Year treat. –Japanese like them fried in oil, then cooked in lemon water. In India, hot pickles are made with them. leaves and the flowers are also used as food, seeds are peeled and eaten husk leaves are used as the basis of medicinal teas in China
The lotus (Nelumbo nucifera) is a fresh-water plant that grows in semitropical climates. It originated in India and was brought to other countries, ranging from Egypt to China, about 2,000 years ago. It is cultivated extensively in Southeast Asia (mostly in China), primarily for food, with much smaller amounts for herbal medicine. All parts of the plant are utilized, but the primary reason for its current widespread cultivation is to collect the rhizomes (sometimes referred to as roots) and seeds. The whole plant is harvested in late summer when the seeds have matured. The rhizomes are a food used extensively in China and Japan, sold whole or in cut pieces, fresh, frozen, or canned. They are consumed as a vegetable, usually fried or cooked in soups. Japan is one of the primary users of the rhizomes, representing about 1% of all vegetables consumed there. Japan grows its own lotus but still has to import 18,000 tons of lotus rhizome each year, of which China provides 15,000 tons.
Arrow root Maranta arundinacea; Family: Marantaceae starchy product of a New World tropical tuber arrowroot starch that you can find in health food stores may actually be almost anything from bananas, rice, potatoes, to starch from almost any tropical root used for thickening sauces; makes very delicate sauces, and it thickens at a lower temperature than corn starch
Arrowroot was introduced into European culture by some of the early European settlers of the New World, who learned of it from the Arawak, the people who lived in the Caribbean Islands (and who still live in remote areas of Guiana, a region of mainland South America due north of Brazil). The Arawak named the plant aru- aru, which meant literally "meal of meals," indicating how highly they valued the starchy food made from the arrowroot tubers. The Arawak also used arrowroot tubers to draw poison from wounds inflicted by poisoned arrows, which is where the name "arrowroot" apparently came from in English, first recorded in 1696.
Breadfruit (Artocarpus altilis), a nutritious starchy melon weighing between two to five pounds was looked upon as an excellent food source for the African slaves in the plantations of the Caribbean. Although it is a fruit, it’s light yellow flesh has the starchy consistency of unripe potatoes which makes it seem more like a vegetable. As the breadfruit ripens it softens to about the consistency of a mango but without the sweetness. The reason for the name “breadfruit” is that when eaten before it is ripe, breadfruit not only feels like fresh bread, but also tastes like it. Not only are breadfruit trees in the Pacific prized for their fruits but their wood is also highly valuable. In Hawaii, the wood of breadfruit trees were made into fine quality canoes, drums, and surfboards. In Guam and Samoa, the bark of the breadfruit trees were used for making tapa cloth.
Food: The roots may be ground into a flour. The sticky sap between the leaves is an excellent starch and can be used to thicken soups and broths. The white colored shoots at the base of the leaf clusters can be boiled or steamed or sliced and eaten raw in salads. Cattail (Typha species); Typhaceae