The most common heat stable colourings in soup are turmeric or beta-carotene for yellow, caramel colour for brown, and either titanium dioxide or calcium carbonate to enhance the white hue of a cream base. Lycopene may be an option to strengthen the red hue of tomato-based soup.
For soup concentrate, salt stability should be considered when using caramel colour. DDW 201, 203 or 301 (Class III) provides stability up to 20% salt solution.
Higher colour intensities are available with salt stability up to 10% salt solution. Caramel colour enhances savory (e.g., beef) appearance to overcome graying or colour loss due to the retort process.
Consumers in many regions prefer dry, shelf stable soups for convenience at home or the workplace. Soup base in its dry form allows for a wide variety of colouring due to minimal heat processing.