Sugars have a carbonyl group that interacts with an hydroxyl group that forms a ring structure when the dry molecule is placed in water. Let take a look at sucrose for example.
Sucrose have the molecular formula of C₁₂H₁₂O₁₁. Its preparation is gotten from a juice of sugar cane. In the process of extracting the juice from sugar cane, the extraction process is done with water usually 80°C. The solution is then treated (purification) afterwards with slaked lime and carbon(iv)oxide. During this stage, the (-C=O) group interfere with the OH group in order to form a ring structure.
