Why is sucrase called invertase?

Sucrase 
Sucrase (systematic name: beta-fructofuranosidase) is an intestinal enzyme that hydrolyzes sucrose.
C12H22O11   +   H2O   →   C6H12O6    +   C6H12O6
 (sucrose)        (water)         (glucose)          (fructose) 
Sucrase Secretion 
It is not present in newborn animals so that they are unable to digest sucrose and feeding of the sugar will cause severe, osmotic diarrhea. Sucrase activity in the intestine increases as the need for, and secretion of, lactase decreases with age.
Why is it called invertase? 
Sucrase is also known as invertase or saccharase. It catalyzes the hydrolysis (breakdown) of sucrose (table sugar) to fructose and glucose, usually in the form of inverted sugar syrup. Invert sugar is the mixture of glucose and fructose produced by hydrolysis of sucrose, 1.3 times sweeter than sucrose. It is called invert sugar because the optical activity is reversed in the process.
The method of measuring the concentration of sugar syrup 
The concentration of sugar syrup is measured using a polarimeter. Plane-polarized light, when passed through a sample of pure sucrose solution, is rotated to the right (optical rotation). As the solution is converted to a mixture of sucrose, fructose and glucose, the amount of rotation is reduced until (in a fully converted solution) the direction of rotation has changed (inverted) from right to left.