Sugar from starch
- High fructose corn syrup
CHAPTER 7 IN THE TEXT
Sugar (sucrose) is a fairly recent product. It didn't become generally
available until about a century and a half ago. Before manufactured sugar
became available, people used honey. Today sugar is a major product and
is derived from several plants.
Sugar occurs in small amounts in most plants. In the plant, sugars are
converted to starch for storage as an energy reserve. This process is
reversible. Enzymes catalyze the reaction.
Sugars are water soluble, whereas starch is not. The process also can
be catalyzed chemically. In general, cost determines what can be used as
a sugar source. A major use of sugar is as a preservative for food
Actually, most sugar today in the U.S. and many other countries comes
from corn (Zea mays). This is sold and used as high fructose corn
syrup. Starch is hydrolyzed with enzymes, or less commonlyl today with acid,
to make a mixture of fructose and glucose. Most soft drinks are now made with
this type of sweetener.
Major sugar producers are Brazil, the former U.S.S.R., U.S.A. and Cuba.
Sugarcane (Saccharum officinarum, Poaceae) is a grass that
originally came from New Guinea. The process of producing sugar from
cane has been known in India since 3000 B.C. Alexander the Great brought
information about sugar cane back to Europe in about 300 B.C.
Although some sugar cane got to Europe, it did not become common and
honey was the only common sweetener until about 1500. Sugar often was
used to make medicines more palatable. It was otherwise only available
to the extremely rich.
Although sugar cane would not grow well in most of Europe, it was grown
in the Mediterranean area. Columbus brought sugar cane to the New World
on his second voyage. Sugar became a major crop in the West Indies and
its history became linked intimately with the history of the New World.
Black slaves were imported into the New World largely to cultivate sugar
The "sugar triangle" took slaves from Africa to the West Indies, raw
sugar and molasses to New England or England and other trade goods from
England to West Africa to trade for slaves.
Sugar cane is a complex origin crop. Several species are probably
involved and modern sugar cane cultivars are complex polyploids. The
crop is usually reproduced vegetatively.
Most of the good cultivars resulted from Dutch plant breeding work in
Indonesia (Dutch East Indies) in the last century.
In the U.S., production is highly mechanized, but in most of the world
it is not.
The process used to isolate sugar from sugar cane is diagrammed on page
Sugarcane is cut 22-24 months after planting. In many countries, the
leaves are burned off first. The cane is forced through rollers that
remove the juice. The plant material is called bagasse and is used to
make paper, for fuel or as a source of wax in many countries.
Sugar cane sap often is about 20% sugar.
In the U.S., Texas, Hawaii and Louisiana are major producing states.
Sugar beets (Beta vulgaris, Chenopodiaceae) are selections of
ordinary beets that are especially rich in sugar. Although a process for
isolation of sugar from sugar beets was first
developed about 1747, the process did not become widely used until about
130 years later.
Napoleon I recognized the importance of this type of sugar. Many sugar
beets today have over 20% sugar.
Sugar beets are harvested in the fall of the year in which they are
planted. The tops are sometimes used for animal feed. The beets are
washed, shredded, and crushed.
Sugar beets are grown in temperate areas of the world. About 2/5's of
the world's sugar comes from sugar beets.
California is a major producing state.
Sugar beets are also used to produce pectin.
Sugar beet field
The expressed juice is heated with calcium hydroxide or water and allowed
to cool and settle. The clear upper layer is siphoned off and sent to an
evaporator. The lower part is filtered and then added to the
The syrup is heated under vacuum to remove water. When the syrup begins
to crystallize the sugar is removed by centrifugation.
The remaining brown liquid is molasses (from sugar cane). Molasses often
is used to make rum, but is also a major ingredient of livestock feeds.
Raw sugar then is redissolved and recentrifuged to remove other
Filtering agents (such as activated charcoal or diatomaceous earth) then
are used to clarify and decolorize the syrup. The final crystallization
yields white granulated sugar.
Trees of the maple group (Acer saccharum, Aceraceae) are used to
make syrup by concentration of the liquid tapped from the trees. The
early Europeans learned how to tap the trees and make the syrup from the
Indians, but the settlers taught the Indians how to make sugar from the
resulting syrup. Maple sap is about 8% sugar.
The stems of sorghum (Sorghum bicolor) also are used to prepare
"molasses". This used to be widely made in the Southeastern U.S., but
is no longer common.
The sap from a number of palm trees is used to prepare sugar.
Phoenix, Borassus, Arenga, Cocos. Ancient in India.
Also used in many parts of Africa. Cut off inflorescence and collect
Other plant sweeteners
Other sweeteners from plants have been used in a number of countries.
The leaves of Stevia rebaudiana, (Asteraceae or Compositae) contain
diterpene glycosides that are more than 300 times sweeter than sucrose.
These were used by the Indians of Paraguay. About 6% in the leaves.
Today the plant is used as a sweetener and exported from Japan.
Licorice, the root of Glycyrrhiza glabra, Fabaceae or
Leguminosae, contains a saponic glycoside called glycyrrhizin. This is
used to flavor pharmaceuticals, candy and tobacco. The miracle fruit,
Synsepalum dulciferum, Sapotaceae, contains a protein that causes
sour substances to taste sweet.
Serendipity berries, Dioscoreophyllum cumminsii, Menispermaceae,
contain an intensely sweet protein.
As mentioned above, sugar in plants is converted to starch. All plants
contain starch also. Again, which plants are important for starches
depends on a number of economic factors.
Starch is widely used for sizing textiles and paper, coating paper, in
rubber and plastics, chewing gum, candy, adhesives, laundry starch, some
paints, detergents, etc. Used to make "super-slurper". Large amounts
are used to make high fructose corn syrup.
Starch is common in many of our food plants. We already talked about
potatoes, corn, cassava, etc. As it turns out these are major starch
In the U.S., most starch comes from Zea mays. The starch is a by
product of oil extraction. The corn is steeped with sulfurous acid, it
is softened and then cracked, the germ floats, the starch sinks. The
hulls are removed.
In the U.S., much of the corn starch is used to make high fructose corn
syrup. Illinois is a leading producing state and in several years has
lead the nation in "sugar" production. Most of the high fructose corn
syrup is used for making soft drinks and commercial good products.
In most tropical countries, cassava serves as a major starch source.
Tapioca is almost pure starch.
In the Orient, most starch comes from rice. In Europe, most starch comes
Arrowroot starch is supposed to be especially edible. It comes from
Maranta arundinacea(Marantaceae) although starch from Canna
edulis(Cannaceae) and Curcurma angustifolia(Zingiberaceae) is
substituted at times.
Sago starch from Metroxylon sagu, Arecaceae, in Malaya and the
East Indies, but Cycas circinalisin Oceania. The latter contains
Revised February 2005
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© David S. Seigler, Integrative Biology 363, Plants and Their Uses,
Department of Plant Biology, 265 Morrill Hall, 505 S. Goodwin Ave., University of Illinois,
Urbana, Illinois 61801, USA. 217-333-7577. email@example.com.