   #copyright

Sugar beet

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

   Two sugar beets - the one on the left has been cultivated to be
   smoother than the traditional beet, so that it traps less soil.
   Enlarge
   Two sugar beets - the one on the left has been cultivated to be
   smoother than the traditional beet, so that it traps less soil.

   Sugar beet (Beta vulgaris L.), a member of the Chenopodiaceae subfamily
   and the Amaranthaceae family, is a plant whose root contains a high
   concentration of sucrose. It is grown commercially for sugar.

   The sugar beet is directly related to the beetroot, chard and fodder
   beet, all descended by cultivation from the sea beet.

   The European Union, the United States, and Russia are the world's three
   largest sugar beet producers, although only Europe and Ukraine are
   significant exporters of sugar from beet. Beet sugar accounts for 30%
   of the world's sugar production.

Culture

   Sugar beet is a hardy biennial plant that can be grown commercially in
   a wide variety of temperate climates. During its first growing season,
   it produces a large (1–2 kg) storage root whose dry mass is 15–20%
   sucrose by weight. If not harvested, during its second growing season,
   the nutrients in this root are consumed to produce the plant's flowers
   and seeds. In commercial beet production, the root is harvested after
   the first growing season, when the root is at its maximum size.

   In most temperate climates, beets are planted in the spring and
   harvested in the autumn. At the northern end of its range, growing
   seasons as short as 100 days can produce commercially viable sugarbeet
   crops. In warmer climates, such as in California's Imperial Valley,
   sugarbeets are a winter crop, being planted in the autumn and harvested
   in the spring. Beets are planted from a small seed; 1 kg of beet seed
   comprises 100,000 seeds and will plant over a hectare of ground (1 lb
   will plant about an acre).

   Up until the latter half of the 20th century, sugarbeet production was
   highly labor-intensive, as weed control was managed by densely planting
   the crop, which then had to be manually thinned with a hoe two or even
   three times during the growing season. Harvesting also required many
   workers. Although the roots could be lifted by a plough-like device
   which could be pulled by a horse team, the rest of the preparation was
   by hand. One laborer grabbed the beets by their leaves, knocked them
   together to shake free loose soil, and then laid them in a row, root to
   one side, greens to the other. A second worker equipped with a beet
   hook (a short handled tool something between a billhook and a sickle)
   followed behind, and would lift the beet and swiftly chop the crown and
   leaves from the root with a single action. Working this way he would
   leave a row of beet that could then be forked into the back of a cart.
   Top Ten Sugar Beet Producers - 2005
   (million metric ton)
   Flag of France  France                  29
   Flag of Germany  Germany                25
   Flag of United States  United States    25
   Flag of Russia  Russia                  22
   Flag of Ukraine  Ukraine                16
   Flag of Turkey  Turkey                  14
   Flag of Italy  Italy                    12
   Flag of Poland  Poland                  11
   Flag of United Kingdom  United Kingdom   8
   Flag of Spain  Spain                     7
   World Total                            242
   Source:
   UN Food & Agriculture Organisation (FAO)

   Today, mechanical sowing, herbicide application for weed control and
   mechanical harvesting has removed this reliance on workers.
   A Beet Harvester
   Enlarge
   A Beet Harvester

   Harvesting is now entirely mechanical. The beet harvester chops the
   leaf and crown (which is high in non-sugar impurities) from the root,
   lifts the root, and removes excess soil from the root in a single pass
   over the field. A modern harvester is typically able to cover 6 rows at
   the same time. The beet is left in piles at the side of the field and
   then conveyed into a trailer for delivery to the factory. The conveyor
   removes more soil -a farmer would be penalised at the factory for
   excess soil in his load.

   If beet is to be left for later delivery, it is formed into "clamps".
   Straw bales are used to shield the beet from the weather. Provided the
   clamp is well built with the right amount of ventilation, the beet does
   not significantly deteriorate. Beet that is frozen and then defrosts,
   produce complex carbohydrates that cause severe production problems in
   the factory. In the UK, loads may be hand examined at the factory gate
   before being accepted.

   In the US, the fall harvest begins with the first hard frost, which
   arrests photosynthesis and the further growth of the root. Depending on
   the local climate, it may be carried out in few weeks or be prolonged
   throughout the winter months. The harvest and processing of the beet is
   referred to as "the campaign", reflecting the organization required to
   deliver crop at a steady rate to processing factories that run 24 hours
   a day for the duration of the harvest and processing (for the UK the
   campaign lasts approx 5 months). In the Netherlands this period is
   known as "de bietencampagne", a time to be careful when driving local
   roads in the area the beets are grown. The reason for this is the
   naturally high clay content of the soil, causing slippery roads when
   soil falls from the trailers during transport.

Processing

Reception

   After harvesting the beet are hauled to the factory. Delivery in the UK
   is by hauler or, for local farmers, by tractor and trailer. Railways
   and boats were once used in the UK, but no longer. Some beet was
   carried by rail in the Republic of Ireland, until the 2006 shutdown of
   sugar beet production in the country due to the end of subsidies.

   Each load entering is weighed and sampled before tipping onto the
   reception area, typically a "flat pad" of concrete, where it is moved
   into large heaps. The beet sample is checked for
     * soil tare - the amount of non beet delivered
     * crown tare - the amount of low sugar beet delivered
     * sugar content ("pol") - amount of sucrose in the crop
     * nitrogen content - for recommending future fertilizer use to the
       farmer.

   From these the actual sugar content of the load is calculated and the
   grower's payment determined.

   The beet is moved from the heaps into a central channel or gulley where
   it is washed towards the processing plant.

Diffusion

   After reception at the processing plant the beet roots are washed,
   mechanically sliced into thin strips called cossettes, and passed to a
   machine called a diffuser to extract their sugar content into a water
   solution.

   Diffusers are long (many metres) vessels in which the beet slices go in
   one direction while hot water goes in the opposite direction. The
   movement may either be by a rotating screw or the whole unit rotates
   and the water and cossettes move through internal chambers. There are
   three common designs of diffuser, the horizontal rotating 'RT' (from
   "Raffinière Tirlemontoise", the manufacturer), inclined screw 'DDS'
   (Det Danske Sukkerfabrik)), or vertical screw "Tower". A less common
   design uses a moving belt of cossettes and water is pumped onto the top
   of the belt and pours through. In all cases the flow rates of cossettes
   and water are in the ratio one to two. Typically cossettes take about
   90 minutes to pass through the diffuser, the water only 45 minutes.
   These are all countercurrent exchange methods that extract more sugar
   from the cossettes using less water than if they merely sat in a hot
   water tank. The liquid exiting the diffuser is called raw juice. The
   colour of raw juice varies from black to a dark red depending on the
   amount of oxidation which is itself dependent on diffuser design.

   The used cossettes, or pulp, exits the diffuser at about 95% moisture
   but low sucrose content. Using screw presses, the wet pulp is then
   pressed down to 75% moisture. This recovers additional sucrose in the
   liquid pressed out of the pulp, and reduces the energy needed to dry
   the pulp. The pressed pulp is dried and sold as animal feed, while the
   liquid pressed out of the pulp is combined with the raw juice or more
   often introduced into the diffuser at the appropriate point in the
   countercurrent process.

   During diffusion there is a degree of breakdown of the sucrose into
   invert sugars and these can undergo further breakdown into acids. These
   breakdown products are not only losses of sucrose but also have
   knock-on effects reducing the final output of processed sugar from the
   factory. To limit (thermophilic) bacterial action the feed water may be
   dosed with formaldehyde and control of the feed water pH is also
   practised. There have been attempts at operating diffusion under
   alkaline conditions but the process has proven problematic - the
   improved sucrose extraction in the diffuser offset by processing
   problems in the next stages.

Carbonatation

   The raw juice contains many impurities that must be removed before
   crystallisation. This is accomplished via carbonatation. First, the
   juice is mixed with hot milk of lime (a suspension of calcium hydroxide
   in water). This treatment precipitates a number of impurities,
   including multivalent anions such as sulfate, phosphate, citrate and
   oxalate, which precipitate as their calcium salts and large organic
   molecules such as proteins, saponins and pectins, which aggregate in
   the presence of multivalent cations. In addition, the alkaline
   conditions convert the simple sugars, glucose and fructose, along with
   the amino acid glutamine, to chemically stable carboxylic acids. Left
   untreated, these sugars and amines would eventually frustrate
   crystallization of the sucrose.

   Next, carbon dioxide is bubbled through the alkaline sugar solution,
   precipitating the lime as calcium carbonate ( chalk). The chalk
   particles entrap some impurities and adsorb others. A recycling process
   builds up the size of chalk particles and a natural flocculation occurs
   where the heavy particles settle out in tanks (clarifiers). A final
   addition of more carbon dioxide precipitates more calcium from
   solution; this is filtered off, leaving a cleaner golden light brown
   sugar solution called thin juice.

   Before entering the next stage the thin juice may receive soda ash to
   modify the pH and sulphitation with a sulphur-based compound to reduce
   colour formation due to decomposition of monosaccharides under heat.

Evaporation

   The thin juice, is concentrated via multiple-effect evaporation to make
   a thick juice, roughly 60% sucrose by weight and similar in appearance
   to pancake syrup. Thick juice can be stored in tanks for later
   processing reducing load on the crystallization plant.

Crystallization

   The thick Juice is fed to the crystallisers, recycled sugar is
   dissolved into it and the resulting syrup is called "mother liquor".
   This is concentrated further by boiling under vacuum in large vessels
   and seeded with fine sugar crystals. These crystals grow, as sugar from
   the mother liquor forms around them. The resulting sugar crystal and
   syrup mix is called a massecuite (from French "cooked mass"). The
   massecuite is passed to a centrifuge where the liquid is removed from
   the sugar crystals. Remaining syrup is rinsed off with water and the
   crystals dried in a granulator using warm air. The remaining syrup is
   fed to another crystalliser from which a second batch of sugar is
   produced. This sugar ("raw") is of lower quality with a lot of colour
   and impurities and is the main source of the sugar that is re-dissolved
   into the mother liquor. The syrup from the raw is also sent to a
   crystalliser. From this a very low quality sugar crystal is produced
   (known in some systems as "AP sugar") that is also redissolved. The
   syrup separated is molasses; still containing sugar but with too much
   impurity to be economically processed further.

   There are variations on the above system, with different recycling and
   crystallisation paths.

Other uses

Sugar beet syrup

   An unrefined sugary syrup can be produced directly from sugar beet.
   This thick, dark syrup is produced by cooking shredded sugar beet for
   several hours, then pressing the resulting sugar beet mash and
   concentrating the juice produced until it has the consistency similar
   to that of honey. No other ingredients are used. In Germany,
   particularly the Rhineland area, this sugar beet syrup is used as a
   spread for sandwiches, as well as for sweetening sauces, cakes and
   desserts.

   Commercially, if the syrup has a Dextrose Equivalency above 30 DE, the
   product has to be hydrolyzed and converted to a high fructose syrup,
   much like High Fructose Corn Syrup, or iso-glucose syrup in the EU.

Betaine

   Betaine can be isolated from the by-products of sugar beet processing.
   Production is chiefly by chromatagraphic separation using techinques
   such as the "moving bed".

Uridine

   Uridine can be isolated from sugar beet. Uridine in combination with
   omega 3 fatty acids has been shown to alleviate depression. .

Alternative fuel

   There are plans by BP and Associated British Foods to use agricultural
   surpluses of sugar beet to produce biobutanol in East Anglia in the
   United Kingdom.

History

   A geneticist evaluates sugar beet plants for resistance to the fungal
   disease Rhizoctonia root rot.
   Enlarge
   A geneticist evaluates sugar beet plants for resistance to the fungal
   disease Rhizoctonia root rot.

   Although beets have been grown as vegetables and for fodder since
   antiquity (a large root vegetable appearing in 4000-year old Egyptian
   temple artwork may be a beet), their use as a sugar crop is relatively
   recent. As early as 1590, the French botanist Olivier de Serres
   extracted a sweet syrup from beetroot, but the practice did not become
   common. The Prussian chemist Andreas Sigismund Marggraf used alcohol to
   extract sugar from beets (and carrots) in 1747, but his methods did not
   lend themselves to economical industrial-scale production. His former
   pupil and successor Franz Carl Achard began selectively breeding sugar
   beet from the White Silesian fodder beet in 1784. By the beginning of
   the 19th century, his beet was approximately 5–6% sucrose by weight,
   compared to around 20% in modern varieties. Under the patronage of
   Frederick William III of Prussia, he opened the world's first beet
   sugar factory in 1801, at Cunern in Silesia.

   The development of the European beet sugar industry was encouraged by
   the Napoleonic Wars. In 1807 the British began a blockade of France,
   preventing the import of cane sugar from the Caribbean and in 1813,
   Napoleon instituted a retaliatory embargo. By the end of the wars, over
   300 beet sugar mills operated in France and central Europe. The first
   U.S. beet sugar mill opened in 1838.

Agriculture

   Sugar beet is an important part of a rotating crop cycle.

   Sugar beet plants are susceptible to rhizomania ("root madness") which
   turns the bulbous tap root into many small roots making the crop
   economically unprocessable. Strict controls are enforced in European
   countries to prevent the spread, but it is already endemic in some
   areas. Continual research looks for varieties with resistance as well
   as increased sugar yield.

   Other economically important members of the Chenopodioideae subfamily:
     * Beetroot
     * Chard
     * Mangelwurzel or Fodder Beet

   Retrieved from " http://en.wikipedia.org/wiki/Sugar_beet"
   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
   Documentation License. See also our Disclaimer.
