Question

Which of the following is/are non-reducing sugar molecules?
(i) fructose
(ii) maltose
(iii) sucrose
(iv) lactose

• A. $(i)$ and $(iii)$
• B. $(i)$ and $(iv)$
• C. $(iii)$ only
• D. $(i)$ and $(ii)$

Answer 1

Answer: (C)

Sucrose is a non-reducing sugar. A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerism. The aldehyde functional group allows the sugar to act as a reducing agent. The molecule of sucrose is a disaccharide that is a combination of the monosaccharides glucose and fructose with the formula $C _{12} H _{22} O _{11}$. It is a non-reducing sugar as the molecule does not have the characteristics of reducing sugars.