Which one of the following does not exhibit the phenomenon of mutarotation ?

Options

A. `(-) - ` Fructose
B. `(+) -` Sucrose
C. `(+) -` Lactose
D. `(+) -` Maltose

Answer

B

Explanation

`(+)-` Sucrose does not undergo mutarotation in solution because it does not contain a "free" aldehyde or ketone group.
Only reducing sugars (remember, sucrose is a non-reducing sugar) that exist in hemiacetal and hemiketal forms, undergo mutarotation in aqueous solution. In sucrose, the hemiacetal and hemiketal groups of glucose and furctose are linked together through `O-`atom and thus, not free. Due to the absence of free hemiacetal or hemiketal group, sources does not exhibit mutarotation.