Question
What are reducing and non-reducing sugars? What is the structural feature characterizing reducing sugars ?
Solution
Those carbohydrates which contain free aldehyde or ketonic group reduce Fehling’s solutions and Tollen’s reagent are called reducing sugar e.g., monosaccharides like glucose, fructose, galactose are reducing sugars.
Those carbohydrates which do not contain free aldehydes or ketonic group and do not reduce Fehling’s solution and Tollen’s reagent are called non-reducing sugars, e.g., maltose, lactose, sucrose.
