Artificial Honey - Formation of a Sweet Imitation

Demonstration Experiment on Video

Artificial Honey - Formation of a Sweet Imitation

Objective: Hydrolytic Decomposition of Sucrose, Invert Sugar

Peter Keusch

German version

Supermarket products:
table sugar, citric acid

Apparatus and glass wares:
hotplate
crystallizing dish d = 12 cm
beaker 100 mL
beaker 250 mL
petri dish d = 9 cm

Experimental procedure:

70 g of household sugar are dissolved with stirring in 100 ml of dest. water placed in a crystallizing dish. After adding 40 mL of an aqueous solution of citric acid the mixture is heated for 60 min while stirring. Then the solution is allowed to cool down for 20 minutes.

Result:

On heating and subsequent cooling, the solution is gradually transformed into a yellow viscous liquid.

Video clip (Download RealPlayer .rm file)

Discussion and background:

· Citric acid catalyzes the hydrolysis of sucrose giving a mixture of equal parts of glucose and fructose:

The formed mixture is known as invert sugar, the name stemming from the fact that it rotates the plane of linearly polarized light in the opposite direction of sucrose. Sucrose is dextrorotatory - it rotates polarized light clockwise (+ 66°). The hydrolysis product fructose is strongly levorotatory (-92°). Glucose on the other hand rotates polarized light to the right (+52°). Invert sugar rotates the plane of the polarized light counterclockwise (-20°) due to the strongly levorotatory nature of fructose.

· Artificial honey is the old synonym for invert sugar cream. In order to make a cream, starch sugar and starch syrup are accumulated in commercial made invert sugar.

· Bee honey is an invert sugar formed by the enzyme invertase from nectar gathered by bees. Also bee honey consists basically of glucose and fructose. The honey bee's stomach emits an enzyme, invertase, that chemically breaks down the disaccharide sucrose into the two monosaccharides.

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