Caramel is a concentrated solution obtained from the controlled heating of sucrose or glucose solutions. It is widely used in various food, beverage, and cosmetic applications due to its distinctive color and versatile properties.

Chemical Composition and Structure

Caramel colorant is a complex mixture of various substances formed during the caramelization process. The primary components include caramelan (C12H18O9), caramelene (C36H50O25), and caramelin (C125H188O80). These compounds contribute to the colorant's rich brown to dark brown color and its characteristic flavor and aroma.

Physical Properties

Caramel colorant typically appears as a dark brown liquid or solid. It has high solubility in water and varying degrees of solubility in ethanol, depending on the specific type and formulation. The colorant is known for its stability, resistance to light and heat, and compatibility with a wide range of pH levels.

Industrial Production Process

• Preparation of reagents. The main raw materials include sucrose (table sugar) or glucose and water.
• Dissolution of sugar. The sucrose or glucose is dissolved in water to form a concentrated sugar solution.
• Heating. The sugar solution is heated to high temperatures, typically between 150°C and 180°C. This heating process induces caramelization, during which the sugar decomposes and transforms into colored compounds.
• Addition of chemicals (optional). Depending on the desired type of caramel colorant, chemicals such as acids (citric acid or phosphoric acid), alkalis (sodium hydroxide), or salts (sodium chloride or ammonium sulfate) may be added to control the caramelization process and achieve the desired properties.
• Concentration. The caramelized solution is further concentrated through evaporation to reduce the water content and increase the color density.
• Filtration. The concentrated solution is filtered to remove any solid impurities and obtain a clear, uniform solution.
• Cooling. The caramelized solution is cooled to room temperature.
• Quality control. The caramel colorant undergoes rigorous quality testing to ensure it meets standards for purity, color intensity, and safety. These tests include chemical analysis, spectroscopy, and physical tests to determine density and viscosity.

What it is used for and where

Food

A food additive colouring agent included with the number E150 in the list of European food additives. This number includes 4 types of Caramel :

• E150a : Plain caramel
• E150b : Caustic sulphite caramel
• E150c : Ammonia caramel
• E150d : Sulphite ammonia caramel

They are obtained from sugar by an industrial process using high temperatures and burning. The colour is dark and can vary from brown to black.

For E150c and E150d, there is an Acceptable Daily Intake (ADI) of about 200mg/kg body weight, while for E150a and E150b there is no ADI.

In particular, E150d - sulphite-ammoniacal caramel is a rather controversial colouring agent that is used in foodstuffs and is part of the E150 family of additives, all of which are colourants.  

Cosmetics

Restricted cosmetic ingredient as IV/146 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:

• Caramel. Wording of conditions of use and warnings    Purity criteria as set out in Commission Directive 95/45/EC (E150a-d)

Cosmetics - INCI Functions

Colorant. This ingredient has the function of colouring the solution in which it is inserted in a temporary, semi-permanent or permanent manner, either alone or in the presence of the complementary components added for colouring.

Fragrance. It plays a very important role in the formulation of cosmetic products as it provides the possibility of enhancing, masking or adding fragrance to the final product, increasing its marketability. It is able to create a perceptible pleasant odour, masking a bad smell. The consumer always expects to find a pleasant or distinctive scent in a cosmetic product. 

The most relevant studies and their abstracts have been selected to explore this topic:

Caramel studies

• Molecular Formula    C₇H₁₀O₂
• Molecular Weight   126.15
• CAS   8028-89-5
• UNII    T9D99G2B1R
• EC Number   232-435-9
• DSSTox ID  DTXSID0047660
• IUPAC  3,5-dimethylcyclopentane-1,2-dione
• InChl=1S/C7H10O2/c1-4-3-5(2)7(9)6(4)8/h4-5H,3H2,1-2H3
• InChl Key      MIDXCONKKJTLDX-UHFFFAOYSA-N
• SMILES  CC1CC(C(=O)C1=O)C
• NCI    C80151
• JECFA   421   
• FEMA   3269       

Synonyms:

• E150
• Caustic Caramel
• Caramel