Inverted sugar syrup

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Inverted sugar
Clinical data
Pregnancy cat. A (US)
Legal status OTC (US)
Routes Oral, local injection
Pharmacokinetic data
Metabolism Glycolysis, fructolysis
Excretion Normally none (unless glycosuria)
CAS number 8013-17-0 YesY
ATC code C05BB03
PubChem CID 21924868
Chemical data
Formula C12H24O12 
Mol. mass 360.312 g/mol
 N (what is this?)  (verify)

Inverted or invert[1] sugar syrup is a mixture of glucose and fructose; it is obtained by splitting sucrose into these two components. Compared with its precursor, sucrose, inverted sugar is sweeter and its products tend to retain moisture and are less prone to crystallization. Inverted sugar is therefore valued by bakers, who refer to the syrup as trimoline or invert syrup.[2]

In technical terms, sucrose is a disaccharide, which means that it is a molecule derived from two simple sugars (monosaccharides). In the case of sucrose, these monosaccharide building blocks are fructose and glucose. The splitting of sucrose is a hydrolysis reaction. The hydrolysis can be induced simply by heating an aqueous solution of sucrose, but more commonly, catalysts are added to accelerate the conversion. The biological catalysts that are added are called sucrases (in animals) and invertases (in plants). Sucrases and invertases are types of glycoside hydrolase enzymes. Acid, such as lemon juice or cream of tartar, can also accelerate the conversion of sucrose to invert.

Chemical reaction of the inversion[edit]

The term 'inverted' is derived from the method of measuring the concentration of sugar syrup 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.

C12H22O11 (sucrose, Specific rotation = +66.5°) + H2O (water, no rotation) → C6H12O6 (glucose, Specific rotation = +52.7°) + C6H12O6 (fructose, Specific rotation = −92°)
net: +66.5° converts to −39°

Hydrolysis is a chemical reaction in which a molecule breaks down by the addition of water. Hydrolysis of sucrose yields glucose and fructose about 85%, the reaction temperature can be maintained at 50–60 °C (122–140 °F).

Inverting sugar[edit]

Inverted sugar syrup can be easily made by adding roughly one gram of citric acid or ascorbic acid per kilogram of sugar. Cream of tartar (one gram per kilogram) or fresh lemon juice (10 milliliters per kilogram) may also be used.

The mixture is boiled for 20 minutes to get to a temperature of 114 °C (237 °F),[3] and will convert enough of the sucrose to effectively prevent crystallization, without giving a noticeably sour taste. Invert sugar syrup may also be produced without the use of acids or enzymes by thermal means alone: two parts granulated sucrose and one part water simmered for five to seven minutes will convert a modest portion to invert sugar.

All inverted sugar syrups are created from hydrolyzing sucrose to glucose (dextrose) and fructose by heating a sucrose solution, then relying on time alone, with the catalytic properties of an acid or enzymes used to speed the reaction. Commercially prepared acid catalysed solutions are neutralized when the desired level of inversion is reached.

All constituent sugars (sucrose, glucose and fructose) support fermentation, so invert sugar solutions may be fermented as readily as sucrose solutions.

Shelf life[edit]

Invert sugar has a lower water activity than that of sucrose, so it provides more powerful preserving qualities (a longer shelf life) to products that use it.

The shelf life of partial inverts is approximately six months, depending on storage and climatic conditions. Crystallized invert sugar solutions may be restored to their liquid state by gently heating.

Notable uses[edit]

  • Honey is a mixture (principally) of glucose and fructose, giving it similar properties to invert syrup. This gives it the ability to remain liquid for long periods of time.
  • Jam, when made, produces invert sugar during extensive heating under the action of the acid in the fruit.
  • Golden syrup is a syrup of approximately 56% invert syrup, 44% sucrose.
  • Fondant filling for chocolates is unique in that the conversion enzyme is added, but not activated before the filling is enrobed with chocolate. The very viscous (and thus formable) filling then becomes less viscous with time, giving the creamy consistency desired.
  • Cigarettes use inverted sugar as a casing to add flavour.[4]
  • Alcoholic beverage manufacturers often add invert sugar in the production of drinks like gin, Scotch whisky, beer and sparkling wines for flavouring. Candi sugar is a type of invert sugar used in the brewing of Belgian-style beers to boost alcohol content without drastically increasing the body of the beer; it is frequently found in the styles of beer known as dubbel and tripel.

See also[edit]

External links[edit]


  1. ^ The Sugar Association: What are the types of sugar?
  2. ^ Hubert Schiweck, Margaret Clarke, Günter Pollach Sugar” in Ullmann’s Encyclopedia of Industrial Chemistry 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a25_345.pub2
  3. ^ Invert sugar recipe
  4. ^ "BAT Global Ingredients". British American Tobacco. Retrieved 2009-08-27.