The sugars possessing free aldehyde groups or free keto groups posses reducing properties.
This reducing property is exhibited by Fehling’s test where the Cu2” ion in Fehling’s solution is reduced to Cu+ ion. All monosaccharides are reducing sugar.
In disaccharides sucrose is none reducing as the aldehyde group of glucose and keto group of fructose are involved in the formation of glycosidic linkage. Other disaccharides like lactose, maltose etc. are reducing sugars.
Artificial Sweetener: These are non-sugar sweetener mostly used by diabetics and health conscious people. They have no nutritive value.
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Saccharin (C6H5CH3) is the most widely used artificial sweetener.
Sucaryl Sodium is 30 times sweeter than sucrose/ Monellin is a protein sweetener and 2,000 times sweeter than sucrose.
Functions:
1. Many monosaccharides like trioses, tetroses, and pentosies are important metabolic intermediates.
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2. Pentoses like ribose and deoxyribose form parts of the ribonucleic acid and deoxyribonucleic acid respectively.
3. Pentoses form the parts of co-enzymes like CoA, FAD, NAD, NADP and ATP etc.
4. the most important protein on earth RUBISCO (Ribulose-i, 5-bisphosphate carboxylase-oxygenase) catalyzes the carbon assymilation. In this process Ribulose-i, 5-bisphosphate (a double phosphorylated ketopentose) accepts CO2 during photosynthesis.
5. Glucose is the blood sugar and fructose is the common fruit sugar.
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6. Oligosaccharides forming the part of glycoprotein function as membrane component. These oligosaccharides from the cell coat or glycocalyx.
7. In some plants like sugarcane disaccharides sucrose is the reserve food.
8. Polysaccharides like cellulose, chitin and pectin are structural components of cell wall.
9. Starch, glycogen, innulin are storage polysaccharides.