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Sugarcane

2007 Schools Wikipedia Selection. Related subjects: Food and agriculture;
Plants

                 iSugarcane
   Sugarcane leaves
   Sugarcane leaves
         Scientific classification

   Kingdom:  Plantae
   Division: Magnoliophyta
   Class:    Liliopsida
   Order:    Poales
   Family:   Poaceae
   Genus:    Saccharum
             L.

                                   Species

   Saccharum arundinaceum
   Saccharum bengalense
   Saccharum edule
   Saccharum officinarum
   Saccharum procerum
   Saccharum ravennae
   Saccharum robustum
   Saccharum sinense
   Saccharum spontaneum

   Sugarcane or Sugar cane (Saccharum) is a genus of 6 to 37 species
   (depending on taxonomic interpretation) of tall grasses (family
   Poaceae, tribe Andropogoneae), native to warm temperate to tropical
   regions of the Old World. They have stout, jointed, fibrous stalks that
   are rich in sugar and measure 2 to 6 meters tall. All of the sugarcane
   species interbreed, and the major commercial cultivars are complex
   hybrids.

Cultivation and uses

   About 200 countries grow the crop to produce 1,324 million tons (more
   than six times the amount of sugar beet produced). As of the year 2005,
   the world's largest producer of sugar cane by far is Brazil. Uses of
   sugar cane include the production of sugar, Falernum, molasses, rum,
   and ethanol for fuel.

History

   Sugarcane is a grass originally from tropical Southeast Asia (Hortus
   Third). The thick stalk stores energy as sucrose in the sap. From this
   juice, sugar is extracted by evaporating the water. Crystallized sugar
   was reported 2500 years ago in India. Around the eighth century A.D.,
   Arabs introduced sugar to the Mediterranean and it was cultivated in
   Spain. It was among the early crops brought to the Americas by
   Spaniards.

   Sugarcane was grown extensively in the Caribbean, and still is on some
   islands. In colonial times, sugar was a major product of the triangular
   trade of New World raw materials, European manufactures, and African
   slaves. France found its sugarcane islands so valuable it effectively
   traded Canada to Britain for their return of Guadeloupe, Martinique and
   St. Lucia at the end of the Seven Years' War. The Dutch similarly kept
   Suriname, a sugar colony in South America, instead of seeking the
   return of the New Netherlands (New Amsterdam). Cuban sugarcane produced
   sugar that received price supports from and a guaranteed market in the
   USSR; the dissolution of that country forced the closure of most of
   Cuba's sugar industry. Sugarcane remains an important part of the
   economy of Barbados, the Dominican Republic, Guadeloupe, Jamaica,
   Grenada, and other islands. The sugarcane industry is a major export
   for the Caribbean, but it is expected to collapse with the removal of
   European preferences by 2009.

                   Sugar cane Saccharum officinarum at Kew Gardens, London
                                                                   Enlarge
                   Sugar cane Saccharum officinarum at Kew Gardens, London

                                     Saccharum officinarum grown in Hawaii
                                                                   Enlarge
                                     Saccharum officinarum grown in Hawaii

                                               Sugar cane field on Madeira
                                                                   Enlarge
                                               Sugar cane field on Madeira

                                           Sugarcane flowering, Australia.
                                                                   Enlarge
                                           Sugarcane flowering, Australia.

   Sugarcane production greatly influenced many tropical Pacific islands,
   most particularly Hawaii and Fiji. In these islands, sugar came to
   dominate the economic and political landscape after the indigenous
   societies had been invaded by Europeans and Americans, who promoted
   immigration from various Asian countries for workers to tend and
   harvest the crop. Sugar-industry policies eventually established the
   ethnic makeup of the island populations that now exist, profoundly
   affecting modern politics and society in the islands.

   Brazil is a major grower of sugarcane, which is used to produce sugar
   and provide the alcohol used in making gasohol and biodiesel fuels.

Cultivation

   Sugarcane cultivation requires a tropical or subtropical climate, with
   a minimum of 600 mm (24 in) of annual moisture. It is one of the most
   efficient photosynthesizers in the plant kingdom, able to convert up to
   2 percent of incident solar energy into biomass. In prime growing
   regions, such as Hawaii, sugarcane can produce 20 kg for each square
   meter exposed to the sun.

   Sugarcane is propagated from cuttings, rather than from seeds; although
   certain types still produce seeds, modern methods of stem cuttings have
   become the most common method of reproduction. Each cutting must
   contain at least one bud, and the cuttings are usually planted by hand.
   Once planted, a stand of cane can be harvested several times; after
   each harvest, the cane sends up new stalks, called ratoons. Usually,
   each successive harvest gives a smaller yield, and eventually the
   declining yields justify replanting. Depending on agricultural
   practice, two to ten harvests may be possible between plantings.
   Canefields just south of Childers, Australia.
   Enlarge
   Canefields just south of Childers, Australia.

   Sugarcane is used as a food plant by the larvae of some lepidoptera
   species, including turnip moth.

   Sugarcane is harvested by hand or mechanically. Hand harvesting
   accounts for more than half of the world's production, and is
   especially dominant in the developing world. When harvested by hand,
   the field is first set on fire. The fire spreads rapidly, burning away
   dry dead leaves, and killing any venomous snakes hiding in the crop,
   but leaving the water-rich stalks and roots unharmed. With
   knives(usually Cane Knives, but Machetes are also commonly used),
   harvesters then cut the standing cane just above the ground. A skilled
   harvester can cut 500 kg of sugarcane in an hour.

   The sugarcane combine, or chopper harvester, is a harvesting machine
   originally developed in Australia. It cuts the cane at the base of the
   stalk, separates the cane from its leaves, and deposits the cane into a
   cart while blowing the cut leaves back onto the field. Such machines
   can harvest 30 tonnes of cane each hour, but cane harvested using these
   machines must be transported to the processing plant rapidly; once cut,
   sugarcane begins to lose its sugar content, and damage inflicted on the
   cane during mechanical harvesting accelerates this decay.

Processing

   Harvested sugar cane ready for processing.
   Enlarge
   Harvested sugar cane ready for processing.

   Traditionally, sugarcane has been processed in two stages. Sugarcane
   mills, located in sugarcane-producing regions, extract sugar from
   freshly harvested sugarcane, resulting in raw sugar for later refining,
   and in "mill white" sugar for local consumption. Sugar refineries,
   often located in heavy sugar-consuming regions, such as North America,
   Europe, and Japan, then purify raw sugar to produce refined white
   sugar, a product that is more than 99 percent pure sucrose. These two
   stages are slowly becoming blurred. Increasing affluence in the
   sugar-producing tropics has led to an increase in demand for refined
   sugar products in those areas, where a trend toward combined milling
   and refining has developed.

Milling

   Sugar mills at an old plantation in Antigua.
   Enlarge
   Sugar mills at an old plantation in Antigua.

   In a sugar mill, sugarcane is washed, chopped, and shredded by
   revolving knives. The shredded cane is repeatedly mixed with water and
   crushed between rollers; the collected juices (called garapa in Brazil)
   contain 10–15 percent sucrose, and the remaining fibrous solids, called
   bagasse, are burned for fuel. Bagasse makes a sugar mill more than
   self-sufficient in energy; the surplus bagasse can be used for animal
   feed, in paper manufacture, or burned to generate electricity for the
   local power grid.

   The cane juice is next mixed with lime to adjust its pH to 7. This
   mixing arrests sucrose's decay into glucose and fructose, and
   precipitates out some impurities. The mixture then sits, allowing the
   lime and other suspended solids to settle out, and the clarified juice
   is concentrated in a multiple-effect evaporator to make a syrup about
   60 percent by weight in sucrose. This syrup is further concentrated
   under vacuum until it becomes supersaturated, and then seeded with
   crystalline sugar. Upon cooling, sugar crystallizes out of the syrup. A
   centrifuge is used to separate the sugar from the remaining liquid, or
   molasses. Additional crystallizations may be performed to extract more
   sugar from the molasses; the molasses remaining after no more sugar can
   be extracted from it in a cost-effective fashion is called blackstrap.

   Raw sugar has a yellow to brown colour. If a white product is desired,
   sulfur dioxide may be bubbled through the cane juice before
   evaporation; this chemical bleaches many colour-forming impurities into
   colourless ones. Sugar bleached white by this sulfitation process is
   called "mill white," "plantation white," and "crystal sugar." This form
   of sugar is the form most commonly consumed in sugarcane-producing
   countries.

Refining

   In sugar refining, raw sugar is further purified. It is first mixed
   with heavy syrup and then centrifuged clean. This process is called
   "affination"; its purpose is to wash away the outer coating of the raw
   sugar crystals, which is less pure than the crystal interior. The
   remaining sugar is then dissolved to make a syrup, about 70 percent by
   weight solids.

   The sugar solution is clarified by the addition of phosphoric acid and
   calcium hydroxide, which combine to precipitate calcium phosphate. The
   calcium phosphate particles entrap some impurities and absorb others,
   and then float to the top of the tank, where they can be skimmed off.
   An alternative to this "phosphatation" technique is " carbonatation,"
   which is similar, but uses carbon dioxide and calcium hydroxide to
   produce a calcium carbonate precipitate.

   After any remaining solids are filtered out, the clarified syrup is
   decolorized by filtration through a bed of activated carbon; bone char
   was traditionally used in this role, but its use is no longer common.
   Some remaining colour-forming impurities adsorb to the carbon bed. The
   purified syrup is then concentrated to supersaturation and repeatedly
   crystallized under vacuum, to produce white refined sugar. As in a
   sugar mill, the sugar crystals are separated from the molasses by
   centrifugation. Additional sugar is recovered by blending the remaining
   syrup with the washings from affination and again crystallizing to
   produce brown sugar. When no more sugar can be economically recovered,
   the final molasses still contains 20–30 percent sucrose and 15–25
   percent glucose and fructose.

   To produce granulated sugar, in which the individual sugar grains do
   not clump together, sugar must be dried. Drying is accomplished first
   by drying the sugar in a hot rotary dryer, and then by conditioning the
   sugar by blowing cool air through it for several days.

Ribbon cane syrup

   Evaporator with baffled pan and foam dipper for making ribbon cane
   syrup. Three Rivers Historical Society Museum at Browntown, South
   Carolina
   Enlarge
   Evaporator with baffled pan and foam dipper for making ribbon cane
   syrup. Three Rivers Historical Society Museum at Browntown, South
   Carolina

   Ribbon cane is a subtropical type that was once widely grown in
   southern United States, as far north as coastal North Carolina. The
   juice was extracted with horse or mule-powered crushers; the juice was
   boiled, like maple syrup, in a flat pan, and then used in the syrup
   form as a sweetener for other foods. It is not a commercial crop
   nowadays, but a few growers try to keep alive the old traditions and
   find ready sales for their product. Most sugarcane production in the
   United States occurs in Florida and Louisiana, and to a lesser extent
   in Hawaii and Texas.

Sugarcane as foodstuff

   Sugarcane juice vendors in Dhaka, Bangladesh
   Enlarge
   Sugarcane juice vendors in Dhaka, Bangladesh

   In most countries where sugarcane is cultivated, there are several
   foodstuffs and popular dishes derived from it, such as:
     * Direct consumption of raw sugarcane cylinders or cubes, which are
       chewed to extract the juice, and the bagasse is spat out
     * Freshly extracted juice ( garapa, guarab, guarapa, guarapo,
       papelón, or caldo de cana) by hand or electrically operated small
       mills, with a touch of lemon and ice, makes a delicious and popular
       drink.
     * Molasses, used as a sweetener and as a syrup accompanying other
       foods, such as cheese or cookies
     * Rapadura, a candy made of flavored solid brown sugar in Brazil,
       which can be consumed in small hard blocks, or in pulverized form
       (flour), as an add-on to other desserts.
     * Sugarcane is also used in rum production, especially in the
       Caribbean.

   Retrieved from " http://en.wikipedia.org/wiki/Sugarcane"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
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