Caramel color or caramel coloring is a water-soluble food coloring. It is made by heat treatment of carbohydrates (sugars), in general in the presence of acids, alkalis, or salts, in a process called caramelization. It is more fully oxidized than caramel candy, and has an odor of burnt sugar and a somewhat bitter taste. Its color ranges from pale yellow to amber to dark brown.
Caramel color is one of the oldest and most used food colorings for enhancing naturally occurring colors, correcting natural variations in color, and replacing color that is lost to light degradation during food processing and storage. [1] The use of caramel color as a food additive in the brewing industry in the 19th century is the first recorded instance of it being manufactured and used on a wide scale. Today, caramel color is found in many commercially made foods and beverages, including batters, beer, brown bread, buns, chocolate, [2] cookies, cough drops, spirits and liquor such as brandy, rum, and whisky, [3] chocolate-flavored confectionery and coatings, custards, decorations, fillings and toppings, potato chips, [4] dessert mixes, doughnuts, fish and shellfish spreads, frozen desserts, fruit preserves, glucose tablets, gravy, ice cream, pickles, [5] sauces and dressings, soft drinks (especially colas), sweets, vinegar, and more. Caramel color is widely approved for use in food globally but application and use level restrictions vary by country. [6]
Caramel color is manufactured by heating carbohydrates, either alone or in the presence of acids, alkalis, and/or salts. Caramel color is produced from commercially available nutritive sweeteners consisting of fructose, dextrose (glucose), invert sugar, sucrose, malt syrup, molasses, starch hydrolysates, and fractions thereof. The acids that may be used are sulfuric, sulfurous, phosphoric, acetic, and citric acids; the alkalis are ammonium, sodium, potassium, and calcium hydroxides; and the salts are ammonium, sodium, and potassium carbonate, bicarbonate, phosphate (including mono- and dibasic), sulfate, and bisulfite. Antifoaming agents, such as polyglycerol esters of fatty acids, may be used as processing aids during manufacture. [8] Its color ranges from pale yellow to amber to dark brown.
Caramel color molecules carry either positive or a negative charges depending upon the reactants used in their manufacture. Problems such as precipitation, flocculation, or migration can be eliminated with the use of a properly charged caramel color for the intended application.
Internationally, the United Nation's Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) recognizes four classes of caramel color, differing by the reactants used in their manufacture, each with its own INS and E number, listed in the table below. Each class consists of a variety of caramels with their own unique properties that make it suitable for use in specific foods and/or beverages.
Class | INS / E number | Description | Properties, qualities, and benefits [9] | Used in [10] |
---|---|---|---|---|
I | 150a / E150a | Plain caramel, caustic caramel, spirit caramel | Strong aftertaste and mild aroma; color ranges from yellow to red; stable in alcohol, tannin, and salt-rich environments | Whiskey and other high proof alcohols, pet food, cookies, crackers, cereal bars, other baked goods, lemonade products, juice concentrates, and cocoa extenders |
II | 150b / E150b | Caustic sulfite caramel | Mild flavor and aroma; exceptional red tone; good stability in alcohol | Tea, wine, rum, whiskey, brandy, cognac, sherry, some vinegars, light cake mixes, and other snack foods |
III | 150c / E150c | Ammonia caramel, baker's caramel, confectioner's caramel, beer caramel | Sweet aroma; red-brown color; stable in alcohol and salt-rich environments | Beer, cereal, pet food, licorice, confectionery, and gravy, soy, and BBQ sauce |
IV | 150d / E150d | Sulfite ammonia caramel, acid-proof caramel, soft-drink caramel | Very mild flavor and aroma; rich dark brown color; stable in alcohol, tannin, and acid-rich environments | Soft drinks and other carbonated beverages, balsamic vinegar, coffee, chocolate syrups, baked goods, cocoa extenders, pet foods, sauces, soups, meat rubs, seasoning blends, and other flavorings |
Color intensity (or, tinctorial power) is defined as the absorbance of a 1 mg/mL (0.1% weight/volume) solution in water, measured using a 1 cm light path at a wavelength of 610 nanometers (or 560 nm for tinctorial power). [8] In this case, A stands for absorbance and TS stands for total solids.
The color tone of the caramel color is also important. This is defined by the Linner Hue Index, which is the measure of the color hue or red characteristics of the caramel color. It is a function of the absorbance of light of wavelengths 510 and 610 nm. In general, the higher the Tinctorial Power, K0.56, the lower the Hue Index and the lower the red tones. [11]
Various other indices are in use around the world and there are conversion factors between them. [12] [13]
Caramel color is a colloid. Though the primary function of caramel color is for coloration, it also serves additional functions. In soft drinks, it can function as an emulsifier [14] to help inhibit the formation of certain types of "floc" and its light protective quality can aid in preventing oxidation of the flavoring components in bottled beverages. [15]
Internationally, JECFA has set the Acceptable Daily Intake (ADI) of Class I caramel color as "not specified"; that of Class II as 0–160 mg/kg body weight; and that of Class III and IV as 0–200 mg/kg body weight. [16]
The United States Food and Drug Administration (FDA) classifies and regulates caramel color in Title 21 CFR § 73.85 as an approved color additive exempt from certification. Unless a food has a standard of identity, caramel color may be safely used in foods generally at levels consistent with "good manufacturing practice" (GMP).
Caramel color has excellent microbiological stability. Since it is manufactured under very high temperature, high acidity, high pressure, and high specific gravity, it is essentially sterile, as it will not support microbial growth unless in a dilute solution.
When reacted with sulfites, caramel color may retain traces of sulfite after processing. However, in finished food products, labeling is usually required only for sulfite levels above 10 ppm.
In 2010, the International Programme on Chemical Safety (IPCS) concluded that commercially produced caramel color has the same toxicological properties as caramel produced by cooking or heating sucrose, except for those prepared using ammonium (Class III and IV). The IPCS has concluded that caramel color does not exhibit carcinogenicity or mutagenicity, based on its studies. [17] Additional long-term studies support a conclusion that caramel colors are not carcinogenic. [18] While the US FDA, [19] Canadian Health Products and Food Branch [20] and European Food Safety Authority (EFSA) [21] have found caramel color safe for use in food and beverages, California has listed 4-Methylimidazole (4-MeI), a compound formed in the manufacture of Class III and IV caramel colors, in the state's Proposition 65, [22] thus legally including it in the category of chemicals "known to the state to cause cancer or reproductive toxicity". According to the Food Chemicals Codex, 4-MeI in caramel color is allowed up to 250 ppm on a color-adjusted basis, which means 250 ppm maximum for every 0.100 color absorbance of a 0.10% solution at 610 nm. [23] The exposure to 4-MeI at levels present in Class III and IV caramel colors are not expected to be of concern for two reasons. Firstly, 4-MeI does not appear to be genotoxic or metabolized to a reactive metabolite. Secondly, carcinogenic doses of 4-MeI exceed estimates of exposure from the consumption of caramel coloring by several thousand-fold. [18]
Caramel coloring may be derived from a variety of source products that are themselves common allergens, namely starch hydrolysates (from wheat), malt syrup (in general derived from barley), or lactose (from milk). As such, persons with known sensitivities or allergies to food products are advised to avoid foods including generic caramel coloring or first determine the source for the caramel coloring before consuming the food. Caramel color produced from corn or cane-based materials would be unlikely to contain gluten due to the lack of gliadin in the carbohydrates. [24] North American and European manufacturers mostly use glucose derived from corn or wheat to produce caramel color, which is highly processed and is generally considered gluten-free. [25]
Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salting), smoke (smoking), sugar (crystallization), etc. This allows for longer-lasting foods such as bacon, sweets or wines. With the advent of ultra-processed foods in the second half of the twentieth century, many additives have been introduced, of both natural and artificial origin. Food additives also include substances that may be introduced to food indirectly in the manufacturing process, through packaging, or during storage or transport.
E numbers, short for Europe numbers, are codes for substances used as food additives, including those found naturally in many foods, such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly found on food labels, their safety assessment and approval are the responsibility of the European Food Safety Authority (EFSA). The fact that an additive has an E number implies that its use was at one time permitted in products for sale in the European Single Market; some of these additives are no longer allowed today.
Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink. They can be supplied as liquids, powders, gels, or pastes. Food coloring is used in both commercial food production and domestic cooking. Food colorants are also used in a variety of non-food applications, including cosmetics, pharmaceuticals, home craft projects, and medical devices. Colorings may be natural or artificial/synthetic.
Quinoline Yellow WS is a mixture of organic compounds derived from the dye Quinoline Yellow SS. Owing to the presence of sulfonate groups, the WS dyes are water-soluble (WS). It is a mixture of disulfonates (principally), monosulfonates and trisulfonates of 2-(2-quinolyl)indan-1,3-dione with a maximum absorption wavelength of 416 nm.p. 119
Tartrazine is a synthetic lemon yellow azo dye primarily used as a food coloring. It is also known as E number E102, C.I. 19140, FD&C Yellow 5, Yellow 5 Lake, Acid Yellow 23, Food Yellow 4, and trisodium 1-(4-sulfonatophenyl)-4-(4-sulfonatophenylazo)-5-pyrazolone-3-carboxylate.
Sunset yellow FCF is a petroleum-derived orange azo dye with a pH dependent maximum absorption at about 480 nm at pH 1 and 443 nm at pH 13 with a shoulder at 500 nm. When added to foods sold in the United States it is known as FD&C Yellow 6; when sold in Europe, it is denoted by E Number E110.
Carbon black is a material produced by the incomplete combustion of coal tar, vegetable matter, or petroleum products, including fuel oil, fluid catalytic cracking tar, and ethylene cracking in a limited supply of air. Carbon black is a form of paracrystalline carbon that has a high surface-area-to-volume ratio, albeit lower than that of activated carbon. It is dissimilar to soot in its much higher surface-area-to-volume ratio and significantly lower polycyclic aromatic hydrocarbon (PAH) content. However, carbon black can be used as a model compound for diesel soot to better understand how diesel soot behaves under various reaction conditions as carbon black and diesel soot have some similar properties such as particle sizes, densities, and copolymer adsorption abilities that contribute to them having similar behaviours under various reactions such as oxidation experiments. Carbon black is used as a colorant and reinforcing filler in tires and other rubber products; pigment and wear protection additive in plastics, paints, and ink pigment. It is used in the EU as a food colorant when produced from vegetable matter (E153).
Sodium benzoate also known as benzoate of soda is the sodium salt of benzoic acid, widely used as a food preservative (with an E number of E211) and a pickling agent. It appears as a white crystalline chemical with the formula C6H5COONa.
Sodium erythorbate (C6H7NaO6) is a food additive used predominantly in meats, poultry, and soft drinks. Chemically, it is the sodium salt of erythorbic acid. When used in processed meat such as hot dogs and beef sticks, it increases the rate at which nitrite reduces to nitric oxide, thus facilitating a faster cure and retaining the pink coloring. As an antioxidant structurally related to vitamin C, it helps improve flavor stability and prevents the formation of carcinogenic nitrosamines. When used as a food additive, its E number is E316. The use of erythorbic acid and sodium erythorbate as a food preservative has increased greatly since the U.S. Food and Drug Administration banned the use of sulfites as preservatives in foods intended to be eaten fresh (such as ingredients for fresh salads) and as food processors have responded to the fact that some people are allergic to sulfites. It can also be found in bologna, and is occasionally used in beverages, baked goods, and potato salad. Sodium erythorbate is produced from sugars derived from different sources, such as beets, sugarcane, and corn. Sodium erythorbate is usually produced via a fermentation process from D-glucose by Pseudomonas fluorescens bacteria. Most syntheses proceed through the 2-keto-D-gluconic acid intermediate. An urban myth claims that sodium erythorbate is made from ground earthworms; however, there is no truth to the myth. It is thought that the origin of the legend comes from the similarity of the chemical name to the words earthworm and bait.
Allura Red AC is a red azo dye that goes by several names, including FD&C Red 40. It is used as a food dye and has the E number E129.
The Linner hue index, , is used to describe the hues which a given caramel coloring may produce. In conjunction with tinctorial strength, or the depth of a caramel coloring's color, it describes the spectra which a solution of the coloring may produce at different dilutions and thicknesses. It also has applications in brewing.
A dough conditioner, flour treatment agent, improving agent or bread improver is any ingredient or chemical added to bread dough to strengthen its texture or otherwise improve it in some way. Dough conditioners may include enzymes, yeast nutrients, mineral salts, oxidants and reductants, bleaching agents and emulsifiers. They are food additives combined with flour to improve baking functionality. Flour treatment agents are used to increase the speed of dough rising and to improve the strength and workability of the dough.
The cochineal is a scale insect in the suborder Sternorrhyncha, from which the natural dye carmine is derived. A primarily sessile parasite native to tropical and subtropical South America through North America, this insect lives on cacti in the genus Opuntia, feeding on plant moisture and nutrients. The insects are found on the pads of prickly pear cacti, collected by brushing them off the plants, and dried.
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) is an international scientific expert committee that is administered jointly by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). It has been meeting since 1956 to provide independent scientific advice pertaining to the safety evaluation of food additives. Its current scope of work now also includes the evaluation of contaminants, naturally occurring toxicants and residues of veterinary drugs in food.
Ammonium sulfite is the ammonium salt of sulfurous acid with the chemical formula (NH4)2SO3.
Sodium bisulfite (or sodium bisulphite, sodium hydrogen sulfite) is a chemical mixture with the approximate chemical formula NaHSO3. Sodium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions composed of sodium and bisulfite ions. It appears in form of white or yellowish-white crystals with an odor of sulfur dioxide. Regardless of its ill-defined nature, sodium bisulfite is used in many different industries such as a food additive with E number E222 in the food industry, a reducing agent in the cosmetic industry, and a decomposer of residual hypochlorite used in the bleaching industry.
4-Methylimidazole is a heterocyclic organic chemical compound with molecular formula H
3C–C
3H
3N
2 or C
4H
6N
2. It is formally derived from imidazole through replacement of the hydrogen in position 4 by a methyl group. It is a slightly yellowish solid.
The Food Chemicals Codex (FCC) is a collection of internationally recognized standards for the purity and identity of food ingredients.
The topic of sulfite food and beverage additives covers the application of sulfites in food chemistry. "Sulfite" is jargon that encompasses a variety of materials that are commonly used as preservatives or food additive in the production of diverse foods and beverages. Although sulfite salts are relatively nontoxic, their use has led to controversy, resulting in extensive regulations. Sulfites are a source of sulfur dioxide (SO2), a bactericide.