It:Caramel

Caramel 2D structure

Caramel: Information
Systematic name	4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one
Other names	Caramel Furanone, Sotolon, Sugar Lactone
Molecular formula	C₆H₈O₃
SMILES	O=C1OC(C)C(C)=C1O
Molar mass	128.13g/mol
Appearance	Orange/brown liquid
CAS number	28664-35-9
FEMA Number	3634
EG/EC Number	2491364
Council of Europe No.	11834
MDL Number	MFCD00059957
Caramel: Properties
Boiling Point	184°C
Melting Point	26-29°C
Refractive Index	n 20/D 1.492
Hazard Information	Harmful by excess inhalation/swallowing

Caramel is a compound that has been used for a long time in many different foods and drinks due to its sweet taste. It is known under different names such as sugar lactone, caramel furanone (after its chemical name) and sotolon, but it is best known as caramel, after which the food caramel takes its name. It has been designated an E number, E150, as it is used so often in food products as a colouring agent.

3D structure

Uses of Caramel

Caramel has many uses, mostly in food due to its sweet taste but there are less-known uses as a colouring agent:

 • Coca cola and other drinks
 • Caramel sweets (carambar etc.)
 • Desserts (creme brulee, creme caramel)
 • Praline
 • Nougat
 • Syrup
 • Tobacco
 • Cosmetics
 • Detergents
 • Dairy Products

Syntheses

The formation of caramel can happen through two different processes, one being the Maillard Reaction and the other being caramelisation. These are both examples of non-enzymatic browning where sugar reacts to form a multitude of products, one of course being caramel.

Maillard Reaction:

The carbonyl group on a sugar reacts with the amino group of an amino acid in a condensation
A molecule of water is lost to make N-substituted aldosylamine
This compound undergoes Amadori Rearrangement to form ketosamines
From here many products can be formed, although the required one first involves hydrolytic fission producing diacetyls etc
These diacetyls and other products undergo Strecker Degradation to aldehydes and then condensation to aldols
These finally produce the heterocyclic compounds with pleasant aromas including Caramel Furanone.

Caramelisation:

Caramelisation is in general a simpler process.
In this reaction the sugars lose water molecules from their structure through a process called "1,2 & 2,3-enolisation".
The product then fragments to make many compounds including caramel.

The sweet caramel can be made through a more familiar "cooking" method by boiling together milk, sugar, butter, oil, syrup, vanilla essence, water, and glucose at about 170 degrees Celcius.

IR spectrum of Caramel

From the spectrum it is immediately obvious that both the C=O stretch and the O-H stretch are present strongly at 1750cm^-1 and 3300cm^-1 respectively, along with the multiple absorptions for C-H between 1000-1500cm^-1.

HNMR and CNMR of Caramel

List of References

http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/W363405
http://www.pharm-marketing.com/flavor_eng.htm
http://en.wikipedia.org/wiki/Caramel
http://brewery.org/library/Maillard_CS0497.html
(syntheses)