Caramel colouring

One group of colourants which is worth mentioning, even though they are not above suspicion for food, are "caramel colours". These brown materials are essentially end-products of the controlled non-enzymatic heat degradation of edible carbohydrates. Typically the base material is a glucose syrup and the reaction takes place in the presence of heat, pressure and catalyst when ammonia or acid are used. Products produced by the ammonia reaction tend to be much darker than those by the acid methods.

Caramel colours (usually supplied as a solution in water) are used in a wide range of foods, but in biscuits they can be used to enhance baked reddish brown colours or in higher concentration the brown associated with cocoa powder, for example, in Bourbon biscuits.