The trehalose molecule - rotatable in 3 dimensions

Trehalose is a disaccharide - formula C₁₂H₂₂O₁₁ - consisting of two glucose units (12 carbon atoms, and 2 ring-shaped structures, each containing an oxygen atom) - like maltose and cellobiose.

However there are major differences between trehalose, maltose and cellobiose:

The two glucose residues are linked via a differently oriented glycosidic bond - an α (alpha) 1-1 bond - joining them 'head to head' at the C1 position.

Label / unlabel bonding carbon atom numbers.

This bond - effectively an oxygen bridge - is formed as a result of a condensation reaction and it does not leave a section which can open to reveal aldehyde or ketone groups, so it is not a reducing sugar.

Trehalose is widely distributed in Nature. It is found in fungi, bacteria and arthropods, and some plant seeds.