Question

Sucrose, a disaccharide, is often added as a sweetener, but it is not as sweet as its constituent monosaccharides, D-glucose and D-fructose. Besides enhancing sweetness, fructose has hygroscopic properties that improve the texture of foods, reducing crystallization and increasing moisture. In the food industry, hydrolyzed sucrose is called invert sugar, and the yeast enzyme that hydrolyzes it is called invertase. The hydrolysis reaction is generally monitored by measuring the specific rotation of the solution, which is positive ( 66.4°) for sucrose, but becomes negative (inverts) with the formation of D-glucose (specific rotation = 52.7°) and D-fructose (specific rotation = –92°). Consider what you know about the chemistry of the glycosidic bond. Which of the following methods could you use to hydrolyze sucrose to invert sugar nonenzymatically in your kitchen at home? (Many can apply)

a. Cool the solution and add water, stirring constantly

b. Boil the sucrose solution in water

c. Add vinegar (acetic acid) to the solution in a warm water bath

d. Add bleach (pH 12) to the solution in a water bath

Answer 1

In option a, the solution is cooled. But we need to heat the solution. So option a is incorrect. In option b, no catalyst in form of acid is provided which will slow down the reaction considerably which can be deemed as virtually unreactive. In option d, pH is 12, which means it is basic condition which is opposite of the condition required. So option c, has all the conditions for conversion to form invert sugar, i,e H+ from acetic acid, water and heat.