Sucrose is dextrorotatory, but its hydrolysis produces dextrorotatory glucose and laevorotatory fructose. The mixture, known as invert sugar, is laevorotatory due to fructose’s higher laevorotation.

Sucrose undergoes hydrolysis to yield an equimolar mixture of D-(+)-glucose and D-(-) fructose. The glycosidic linkage is between C₁ of a-D-glucose and C₂ of b-D-fructose, involving the reducing groups and making sucrose a non-reducing sugar.

In disaccharides, reducing sugars have free aldehydic or ketonic groups, such as maltose and lactose. Non-reducing sugars, like sucrose, involve these functional groups in glycosidic bond formation.

Glycosidic linkage in disaccharides is formed by the loss of a water molecule, connecting two monosaccharide units through an oxygen atom. It results from the bonding of the reducing groups (aldehydic or ketonic) of monosaccharides.

Fructose belongs to the D-series and is a laevorotatory compound. Its open-chain structure includes a ketonic functional group at carbon number 2.