DISACCHARIDES

KANAV BHANOT

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Roll no. 05

CONTENTS

• DISACCHARIDES• FORMATION• CLASSIFICATION

• BIBLIOGRAPHY

SUCROSE LACTOSE MALTOSE

• When two monosaccharide are combined by glycosidic linkage, a disaccharide is formed. Therefore they yield two molecules of same or different monosaccharide on hydrolysis.

• General formula of Disaccharides : Cn(H2O)n-1

• The disaccharides just like monosaccharides are white crystalline, sweet solids. However, even though they are soluble in water, they are too large to pass through cell membranes.

DISACCHARIDES

FORMATION

Disaccharides are formed when two monosaccharides are joined together and a molecule of water is removed, a process known as dehydration reaction. For example; Milk sugar (lactose) is made from

glucose and galactose. Sugar from sugar cane and sugar

beet (sucrose) is made from glucose and fructose.

Maltose, another notable disaccharide, is made up of two glucose molecules.

There are two different types of disaccharides: I. Reducing disaccharides, in which

one monosaccharide, still has a free hemiacetal unit.

II. Non-reducing disaccharides, in which neither monosaccharide has a free hemiacetal unit.

Example: i. SUCROSE

Example: i. LACTOSE ii. MALTOSE

CLASSIFICATION

SUCROSE

STRUCTUREThe glucose part had the aldehyde at carbon 1, and the fructose part had the ketone group at carbon 2. Since the linkage is 1,2, neither group is free. Therefore, sucrose is not a reducing sugar.

INTRODUCTION The molecule is a disaccharide derived

from glucose and fructose with the molecular formula C12H22O11.

Sucrose is commonly known as table sugar.

It is a white, odourless, crystalline powder with a sweet taste.

FUNCTIONS Used in syrup preparation, tablet

manufacture, nutrient and demulcent . Sucrose is also used in preparation of

dextran (a polysaccharide used as plasma substitute).

LACTOSE

STRUCTUREIt has a 1,4- glycosidic linkage, acts as a reducing sugar because both of the original aldehyde group were on carbon 1, and one of them is free to react.

INTRODUCTION

• Lactose is a disaccharide derived from the condensation of Galactose and Glucose

• Lactose is commonly called Milk Sugar.

• It is Dextrorotatory• Lactose requires you have an enzyme called lactase to digest the disaccharide.

FUNCTIONS• Widely used in food industry.• Also used as filler in tablets.

MALTOSE

STRUCTUREThe aldehyde groups are at carbon 1 in each of the original glucose molecules. Since the linkage is 1,4, one free aldehyde group remains. Therefore, maltose acts as a reducing sugar.

INTRODUCTION

• Maltose, is a disaccharide formed from two units of glucose.

• Maltose is commonly called Malt Sugar.

• It is produced commercially by hydrolysis of starch.

FUNCTIONS• Converted to glucose and used as an

energy source for growing embryo in seed.

• Used in alcohol production.

BIBLIOGRAPHY

The sources that enabled me to bring out this presentation to you all are :

HARPER’S Illustrated Biochemistry

Textbook of Biochemistry by VASUDEVAN

Class Notes