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Sugar
is a term used not only to describe the crystalline sweetener that
we use for sweetening and our tea and coffee, but also to refer to
quite a few chemical compounds in the carbohydrate group. All these
compounds do have some common qualities like being devoid of color
and odor, being in the form of crystals and has a characteristic
sweet taste.
They
all carry the suffix ‘saccharide’ in their names like monosaccharides, disaccharides and trisaccharides. However, it is
important to remember that not all compounds that carry the suffix
‘saccharide’ are sugars. Polysaccharides like starch and
glycogen are not sugars.
All these sugars are present in nature. Who makes them? You may
wonder. Plants, of course. Plants manufacture sugar during the
process of photosynthesis. Sugars are also found in many animal
tissues. Carbon atoms form an important constituent of all
sugars. |
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Monosaccharides contain five carbon atoms in its molecule. Such five
carbon sugars are known as pentoses.
Similarly three, four, six, seven, eight and nine carbon
sugars are also found in nature. Of these, the hexose sugars – the
six carbon – sugars are the most widespread. The chemical formula
for this kind of sugar is C6H12O6.
Important hexose sugars are glucose, galactose and fructose.
You may have come across references to maltose, sucrose and lactose.
These are disaccharide sugars. The chemical formula for disaccharide
sugars is C12H22O11. When these
sugars are treated with either acids or enzymes, they combine with
water and split into two molecules of monosaccharide sugar.
Most sugars when treated with an alkaline solution, other than
sucrose, reduce cupric oxide to cuprous oxide. This chemical
reaction is the basis for testing the level of sugar in blood and
urine. These tests are extremely important for diagnosing diabetes
and for checking the sugar level during treatment of diabetes. The
enzyme present in the human body, which is capable of digesting
sucrose into its constituent molecules of glucose and fructose, is
sucrase.
The sugar that we use to enhance the taste of our food is commonly
referred to as sucrose, saccharose or cane sugar extracted from
tropical sugar cane - Saccharum officinarum. It is, in fact, called
cane sugar even if its source is not sugar cane. Another major
source of sucrose sugar is temperate sugar beet - Beta
vulgaris.
Sucrose
is the source of 13 per cent of the energy that we derive from our
food. Many plants other than sugar cane and sugar beet contain
sucrose. Some of these are a few varieties of palm and sugar maple.
Small quantities of sugar are extracted from the sap of maple trees,
sorghum and from date palms. But for commercial extraction of sugar
the preferred sources are sugar cane and sugar beet.
Of these, sugar cane is the source of more than half the world’s
sugar and the rest is made from sugar beet. Sugar beet is grown
extensively in Germany, France, Poland, Russia, Ukraine and
northwestern US. Major sugar producers of the world are India,
Australia, Mexico, Cuba, Kazhakstan and Brazil. |
