Carbohydrates are classified on the basis of their behaviour on hydrolysis. They have been broadly divided into following three groups :
(i) `color{green}("Monosaccharides ")` : A carbohydrate that cannot be hydrolysed further to give simpler unit of polyhydroxy aldehyde or ketone is called a monosaccharide. About `20` monosaccharides are known to occur in nature. Some common examples are glucose, fructose, ribose, etc.
(ii) `color{green}("Oligosaccharides ")` : Carbohydrates that yield two to ten monosaccharide units, on hydrolysis, are called oligosaccharides.
● They are further classified as disaccharides, trisaccharides, tetrasaccharides, etc., depending upon the number of monosaccharides, they provide on hydrolysis.
● Amongst these the most common are disaccharides. The two monosaccharide units obtained on hydrolysis of a disaccharide may be same or different.
● For example, sucrose on hydrolysis gives one molecule each of glucose and fructose whereas maltose gives two molecules of glucose only.
(iii) `color{green}("Polysaccharides ")` : Carbohydrates which yield a large number of monosaccharide units on hydrolysis are called polysaccharides.
● Some common examples are starch, cellulose, glycogen, gums, etc.
● Polysaccharides are not sweet in taste, hence they are also called non-sugars.
`=>` The carbohydrates may also be classified as either reducing or non-reducing sugars.
● All those carbohydrates which reduce Fehling’s solution and Tollens’ reagent are referred to as reducing sugars.
● All monosaccharides whether aldose or ketose are reducing sugars.
● In disaccharides, if the reducing groups of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars e.g. sucrose.
● On the other hand, sugars in which these functional groups are free, are called reducing sugars, for example, maltose and lactose.
Carbohydrates are classified on the basis of their behaviour on hydrolysis. They have been broadly divided into following three groups :
(i) `color{green}("Monosaccharides ")` : A carbohydrate that cannot be hydrolysed further to give simpler unit of polyhydroxy aldehyde or ketone is called a monosaccharide. About `20` monosaccharides are known to occur in nature. Some common examples are glucose, fructose, ribose, etc.
(ii) `color{green}("Oligosaccharides ")` : Carbohydrates that yield two to ten monosaccharide units, on hydrolysis, are called oligosaccharides.
● They are further classified as disaccharides, trisaccharides, tetrasaccharides, etc., depending upon the number of monosaccharides, they provide on hydrolysis.
● Amongst these the most common are disaccharides. The two monosaccharide units obtained on hydrolysis of a disaccharide may be same or different.
● For example, sucrose on hydrolysis gives one molecule each of glucose and fructose whereas maltose gives two molecules of glucose only.
(iii) `color{green}("Polysaccharides ")` : Carbohydrates which yield a large number of monosaccharide units on hydrolysis are called polysaccharides.
● Some common examples are starch, cellulose, glycogen, gums, etc.
● Polysaccharides are not sweet in taste, hence they are also called non-sugars.
`=>` The carbohydrates may also be classified as either reducing or non-reducing sugars.
● All those carbohydrates which reduce Fehling’s solution and Tollens’ reagent are referred to as reducing sugars.
● All monosaccharides whether aldose or ketose are reducing sugars.
● In disaccharides, if the reducing groups of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars e.g. sucrose.
● On the other hand, sugars in which these functional groups are free, are called reducing sugars, for example, maltose and lactose.