Why dont polysaccharides give a positive test with Fehling's solution?

Answer 1

Fehling test is only suitable for reducing sugars, that means, monosaccharides in its open form with an aldehyd available. Polysacchardes have the aldehydes in a acetal form and they can not react

Answer 2

Polysaccharides do not give a positive test with Fehling's solution because they are too large to form the soluble copper complex required for the reaction. Fehling's solution reacts with reducing sugars to form a red precipitate of copper(I) oxide, but polysaccharides have too many sugar units linked together to effectively participate in this reaction.

Answer 3

because there is only one reducing group for every 2000 to 10000 monosaccharidee units

Answer 4

Monosaccharides are tested with the help of Fehling's solution and give a positive result. Amylose is made up of polysaccharides and hence gives a negative test with the Fehling's solution.