Question

Question #1e49b

Answer 1

There are many different possibilities.

Explanation:

A reducing sugar is any sugar that can act as a reducing agent because it has a free aldehyde group or a free ketone group.

Fructose is a reducing sugar because the open-chain form can isomerize to an aldehyde.

If it is part of a disaccharide, the hemiketal must not be involved in a glycoside linkage.

Here are three reducing disaccharides of glucose and fructose.

Turanose [α-D-glucopyranosyl-(1→3)-D-fructopyranose]

Maltulose [α-D-glucopyranosyl-(1→4)-D-fructofuranose]

Isomaltulose [α-D-glucopyranosyl-(1→6)-D-fructofuranose].

In each case, the hemiketal structure of fructose is retained, so these are all reducing disaccharides.