Caramel Color in Carbonated Soft Drinks
Selecting the appropriate Caramel Color
Caramel color first and foremost delivers color and provides "eye appeal". Caramel provides that color which looks refreshing and entices customers to purchase the beverage. The first choice for soft drink formulators is one of the Class IV caramels. They are negatively-charged with a wide range of color intensities and shades-from red to black. The shade is determined by the caramel manufacturing formulation and measured as Hue Index. The higher the Hue Index value (Class IV caramels range from 4.2 to 5.9), the redder the product. Within any one class of caramel color, there exists and inverse relationship between color intensity (darkness) and hue (redness).
Caramel in aqueous solutions like soft drinks must be chemically-tailored to be compatible with other ingredients. Soft drinks normally carry negatively-charged particles because of tannins derived from plant material, root, bark, etc. Therefore, a negatively-charged caramel should be selected. An important parameter is the isoelectric point or the pH at which the colloidal charge is electrically neutral. Soft drinks need a caramel with an isoelectric point below the pH of the beverage to avoid flocculation/precipitation. A Class IV caramel has an Isoelectric Point between pH 0.5 and 2.0
Malta, a soft drink common in Latin America, represents one of the exceptions as it requires a class III caramel (such as DDW#300 or DDW #304). The Isoelectric Point of a Class III caramel is between pH 5.0 and & 7.0 Malta, a positively-charged product, has a pH around 4.0. So, to avoid flocculation / precipitation one needs a higher isoelectric point to keep the charge positive.
Some beverage designers choose one of the Class I caramels (such as DDW #525 or DDW
#528) for higher hue –more red to yellow tones. The Class I caramels, which have slightly-negative charge and low color intensity, are stable in non-colas if the beverage is above pH 3.5
Caramel I Soft Drink Concentrates
In addition to the obvious function of delivering color, caramel helps to protect flavors from light deterioration. Carmel color also acts as an emulsifying agent in the preparation of soft drink concentrates to reduce the need for gums. A water-insoluble flavoring agent may be added to caramel or vice versa. Sufficient caramel solids must be present to emulsify flavor. A flavor which contains a high percentage of terpenes (e.g., orange oil) is more difficult to emulsify and will require a greater proportion of caramel solids than an agent containing in a small amount of terpenes (e.g., distilled lime oil). Generally all the water –necessary to reserve as the aqueous phase for the emulsification of the flavor—is present in the volume of caramel used. However, one can add more water to adjust the viscosity of the mixture. Most commonly, a homogenizer accomplishes the emulsification. During the emulsification the water-insoluble flavor break into very small particles with diameters ranging from as high as 10 microns to below 1 micron. For a carbonated soft drink application, the average diameter of these particle should be less than 1 micron to achieve a stable emulsion.
Emulsion breakdowns are usually cause by the flavor oils. Flavor emulsion breakdowns of large particle will precipitate to the bottom of the beverage container. Breakdowns of small particle could cause a "plug" or "ring" in the neck of the beverage bottle.
Most Class IV powders (such as DDW #602 or DDW #610) are stable in phosphoric acid and citric acid. Formulators select powdered caramel color in some beverage systems. The majority prefers liquid caramel for its economy.
D. D. Williamson, 1901 Payne Street, Louisville, KY 40206. Tel: 502-895-2438; Fax: 502-895-7381.