Question

Raffinose on hydrolysis gives:
(A) Two monosaccharides
(B) Three monosaccharides
(C) One disaccharide and one monosaccharide
(D) Two monosaccharides and one disaccharide

Answer 1

Hint: We know that monosaccharides are the simplest unit of carbohydrates. In order to know the hydrolysis product, we should understand that on hydrolysis, polysaccharides break down into its constituent simpler carbohydrates like disaccharides and further break down into monosaccharides. So, we will see the constituents disaccharides and monosaccharides of the Raffinose sugar.

Complete answer:
We know that carbohydrates are the sugar molecules. Monosaccharides are the simplest carbohydrates. These monosaccharides join together to form disaccharides, oligosaccharides and polysaccharides. These monosaccharides are joined together through glycosidic linkage.
Monosaccharides are the simplest units of carbohydrates, so they cannot be further hydrolysed to be broken down into simpler units. Disaccharides break down into monosaccharides on hydrolysis.
The sugar present in some cereals like sugar beet, cottonseed is known as Raffinose. It is a trisaccharide. This means that three monosaccharides joined together to form a single unit of Raffinose.
Raffinose consists of glucose, galactose and fructose. Therefore, when we hydrolyse Raffinose, it will produce glucose, galactose and fructose.
We can write the hydrolysis reaction of Raffinose and break down of Raffinose is shown as follows:
$Raffinose \to Glu\cos e + Galactose + Fructose$

Therefore, the correct option is (B) Three monosaccharides.

Note:
We should remember that when two monosaccharide units combine with each other, a disaccharide is formed. An oligosaccharide is a carbohydrate which consists of three to ten monosaccharide units. A polysaccharide is a carbohydrate which consists of more than ten monosaccharide units.