Question

Which of the following is an example for non-reducing sugar?

• A. Glucose
• B. Fructose
• C. Sucrose

Hint:

Sucrose is the most common non-reducing sugar.

Answer 1

The Correct Option is C

Step 1: Concept
Reducing sugars have a free aldehyde or ketone group that can reduce alkaline cupric salts.

Step 2: Meaning
In a non-reducing sugar, the glycosidic bond involves the anomeric carbons of both monosaccharide units, leaving no free reactive group.

Step 3: Analysis
Glucose, Fructose (monosaccharides), and Lactose (disaccharide with a free anomeric carbon) are all reducing. In Sucrose, the linkage is between the $C_{1}$ of glucose and $C_{2}$ of fructose, locking both anomeric centers.

Step 4: Conclusion
Consequently, Sucrose does not reduce Benedict's or Fehling's solution and is a non-reducing sugar.

Final Answer: (C)