“Color has an incredible amount of influence on food acceptability,” says Fergus Clydesdale, distinguished professor and head of the department of food science at University of Massachusetts (Amherst). “As long as nature teaches people that color is important, people are going to insist on having color in their food.”

New hybrids of potatoes, cauliflower and corn in odd colors may mean fewer additives for some processed foods. Seed companies are using traditional breeding and genetic engineering to develop new hybrids of seeds that produce conventional vegetables and fruits to express a rainbow of colors.

“Consumers respond to colors that are visually appealing. It does not seem to matter whether they are derived from a natural or synthetic source,” observes Gale D. Myers, manager of application development for dispersions and coatings at a food coloring company.

“There are no bad ideas as it pertains to [unusual] food coloring,” opines Clydesdale. “Color intensity is a very valuable tool in nursing homes for the elderly who have lost some of their sense of taste. Kids also get a kick out of wild colors that don't exist in nature.” Manufacturers can increase the perception of sweetness up to 10% by coloring fruit-flavored beverages with deeper red colors, purports Clydesdale.

Regardless of what lies over the rainbow, food coloring is highly regulated by the FDA, which defines a color additive as any “dye, pigment or other substance capable of coloring a food, drug, cosmetic or any part of the human body.” Each classification of color additives is highly regulated and must comply with the specifications outlined in the Code of Federal Regulations (CFR), Title 21, sections 70-82.

Certified and Exempt

Color additives are classified as either certifiable or exempt from certification. Exempt colors are referred to generally as natural colors in the industry.

Although most exempt colors can be found in nature, they cannot be deemed natural by the FDA if the color is not found naturally in the product. For example, turmeric oleoresin originates from the dried root of Curcuma longa, a perennial relative of the ginger family. However, if curcumin, the dominant yellow pigment of turmeric, is used to color a banana-flavored product, it is not considered natural. In addition, colors extracted from parts of a plant that are not traditionally used for consumption also cannot be labeled as natural.

Exempt color additives readily available in nature would include such examples as red cabbage juice color and grape juice color that are unmistakably vegetable-based.

The nine certifiable colors are labeled as FD&C, meaning they are suitable for foods, drugs and cosmetics. Certifiable colors largely are referred to as synthetic, artificial or “man-made” colors; however, some of the exempt colors are synthetic duplicates of naturally existing colorants, explains Susan Brunjes, a natural color chemist.

“Certification is unique to the U.S., and the FDA determines which colorants require certification,” says Brunjes. FD&C colors must be declared individually by name on a label, such as FD&C Yellow No. 6.

Beverages, confections, baked goods, dairy products and cereals are just a few examples of products where FD&C dyes commonly are used. There are 31 exempt colors permitted for use in food (see chart).

Although all color additives must be used in amounts consistent with GMPs, some mineral-based pigments such as ferrous gluconate, a black dye used only with ripe olives, can be intended solely for coloring one product. Conversely, other mineral-based colors, like certification-exempt titanium dioxide, can color any food white--as long as the product remains consistent with the product's standard of identity.

Many of the colors, both certifiable and exempt, have specific usage limitations, which include usage levels and, oftentimes, not only restrictions to certain foods, but also to specific parts of certain foods. For example, Orange B, a certifiable color hailing from a disodium salt, can be used only to color casings or surfaces of frankfurters and sausages at a maximum level of 150ppm.

Dyes and Lakes

Colors function in two ways, as a dye or a pigment. “Dyes impart color to a product by dissolving, and pigments impart color by dispersing,” explains Brunjes.

Although most dyes are water-soluble, glycerine and propylene glycol are other common solvents used with FD&C dyes. Dyes are introduced into foods as powder, granular or concentrated liquid colors.

Pigments can be made available in a variety of forms, also, such as lakes and dispersions in various carriers. Oil-soluble colors and water-dispersible emulsions are other forms of colors that can be used in food applications.

Lakes are made by precipitating a water-soluble dye onto an aluminum hydroxide substrate to create an insoluble dye. Lakes are dispersed like sugar to impart their color.

“With any color, regardless of whether it is natural or synthetic, properties specific to that color additive need to be considered,” informs Brunjes. Each color needs to be evaluated individually based on the application and factors such as heat, light, pH, processing, regulatory status and other ingredients in the application that could affect color stability.

“Certain ingredients, such as ascorbic acid or trace metals, can also accelerate the degradation of some color additives,” informs Brunjes. In some applications, such as beverages, EDTA can slow the degradation of ascorbic acid, thereby slowing the deterioration of the colorant. However, in colorants such as beta-carotene and cochineal extract, ascorbic acid can actually enhance the stability.

“If product developers are not limited to using only synthetic or only natural colors, they can achieve some unique shades by using synthetics and naturals together in an application,” says Brunjes. For instance, combining Blue 1 with natural red color options such as carmine (a red color extracted from the shell of the cochineal beetle) or fruit/vegetable juice can yield brighter purple shades than what can be achieved using Blue 1 in combination with Red 40.

Also, combining synthetic colors like Blue 1 or Red 40 with turmeric can yield neon-type shades, says Brunjes. Again, considerations need to be made to ensure that the colorants chosen are technically appropriate for the application. “It is possible to obtain a choice of natural colors that are fairly stable but it's more difficult to maintain stability in certain foods,” warns Clydesdale. “They also don't have the tinctorial strength of the synthetic colors.”

How Now, Brown Cow?

Caramel color is a prime example of how physical alteration can affect the hue of a color. Offering varied shades of brown, caramel color is manufactured by the controlled heat process of food grade carbohydrates, such as corn syrup or sucrose.

The four color classes of caramel--plain (class I), caustic sulfite (class II), ammonia process (class III) and sulfite ammonia (class IV)--have distinct characteristics, which are specific for certain food and beverage applications. Class I caramels often are used to tint high-proof alcohols. Class III caramel, the most common of the three, is found browning baked goods, confections and beer, while Class IV, suitably named the “acid proof caramel” is utilized in carbonated beverages.

With golden yellows to barely blacks, caramels can be used in a wide range of applications, with some of the more common being beverages, baked goods, syrups, candies, sauces and seasonings.

Caramel colors are produced to meet specifications to ensure consistency. The higher the value of the absorbance (i.e., that is, the tinctorial power, KO.56), the darker the caramel color. “Caramel color is relatively low in tinctorial strength, in comparison to other colors,” says Brunjes.

Malted and roasted grain colors are a widely used source of color in beers and stouts. Their all-natural, organic, non-GMO labeling stands to give caramel a run for its money, but they still have a long way to go.

Caramel color has not had much competition, as synthetic colors are not often used to make brown or black because, among other disadvantages, they do not have enough color intensity. “Colors from malted grains are more soluble and have more intense color than cocoa or molasses, the other alternatives to caramel color. Plus it can be labeled as a whole grain flour and it doesn't have the stigmas associated with caramel color,” explains Bob Hansen, manager, technical services at a malt supplier.

An alternative for baked goods, non-clear beverages and other non-liquid products such as meat patties, malt color costs about the same as dried caramel colors but is less expensive than cocoa.

Colors from malted grains are achieved by grinding barley or other grains into fine flour. Black malted extracts are half the color intensity of a class I caramel. Malted colors can be used like caramel and cocoa in baked goods or in meat analogs like a soy bratwurst.

Coloring with specialty malt flours is the equivalent of using both a dye and a lake simultaneously. “Malt flours act like a lake but, because a lot of the color is soluble, it also acts as a wash,” informs Hansen. Malt flour can provide both soluble and insoluble color and add fiber to the product.

In baked applications, this can be a significant bonus, but in a beverage, the insoluble material would settle out, producing specks throughout the product. Also, by diluting the color to a great extent in hopes of producing a tan, reddish or golden hue, the soluble color would dilute but the specks would remain dark. “To achieve 100% solubility, a liquid extract can be concentrated from the soluble grain colors,” says Hansen. Additionally, caramelized malts also can generate a reddish or golden hue.

In Living Color

Availability is a problem with natural colors, says Hansen. “The spectrums of colors that can be naturally isolated aren't as wide as what can be made in a lab. One of the biggest problems with natural colors is that the availability in blues basically doesn't exist. They can't be isolated.”

In general, synthetic colors tend to have a lower cost-in-use than natural colors. “However, this needs to be assessed on a case-by-case basis,” explains Meyers. “In most instances, it is not possible to make a comparison on cost.”

“Depending on the application and desired shade, a natural color may offer better stability than a synthetic color of comparable shade,” suggests Brunjes. Nevertheless, extreme heat produced, for instance, by ultra pasteurization, UV light, and even active bacteria can destabilize pigments, causing a change in shades.

Some natural colors also provide further functionality to promote health. For example, lycopene has been linked to a reduced incidence of certain cancer types, such as prostate cancer, and a lower heart-attack risk. Lycopene can be used as a natural red colorant in a variety of foods such as soy meat substitute products, pasta, cereals and smoothie drinks.

A study published in the Journal of Agricultural and Food Chemistry's website on December 17, 2004 suggested that anthocyanins, like those found in purple carrots, rubini and red cabbage, increased insulin production in animals by 50%. If such research rings to be true, cherries and blackberries, which are colored by the anthocyanin pigment, could be a useful contribution to a diet purposed to control blood-sugar levels in people with type 2 diabetes, and prevent the condition in others. As pH rises above three, anthocyanins can reflect more blue tones. At pH 7, they have purple hues resembling concord grapes.

Beta-carotene, known for the orange color in carrots, is converted in the body to vitamin A, which promotes clear vision, bone growth and healthy reproduction.

On the other side of the spectrum, inkjet printers are being used in food imaging systems using piezoelectric printheads and inks specifically for printing full color images and words onto food products the same way a desktop printer would be used at home. The most recent manifestation of such endeavors is Pringles' (Proctor & Gamble, Cincinnati) Prints, with Trivial Pursuit questions printed on each chip.

“The commercially available technology can print onto a wide range of foods such as crackers, chips, baked goods, waffles, pancakes, cookies, tortillas and other snack foods--essentially anything with some surface porosity,” says Robert Baydo, technical director for inkjet inks at a color and flavor supplier. He says the technology will expand into candies and chocolates in 2005.

Sidebar: Going Global

Concord Confections (Ontario) released Razzles Tropical Gum Candy in Saudi Arabia last December. The available flavors in pineapple, strawberry-banana, tropical punch, tangerine and kiwi lime have colors derived from FD&C red 40 lake, blue 1 lake, yellow 5 lake and yellow 6 lake.

Hartwell (Helsinki, Finland) manufactures Suklaa Porter Malt Beer as a part of a line of flavored alcoholic beverages. Malt is used in this case for flavor in making dark "chocolaty," full-malt beer, said to derive its soft taste and full-bodied nose from special dark malts, roasted malts and chocolate flavoring, which also contributes to the color.

Green's Traditional Chocolate Cake Mix by Green's General Foods (Glendenning, Australia) boasts that it does not have any artificial flavors or colors but includes caramel color on the ingredient legend.

New under the Birds Eye brand (Surrey, U.K.), Mild Chicken Korma with Two Color Rice contains no artificial colors or preservatives. Turmeric is used as a natural color.

Breakfast in Taiwan will be interesting with Quaker Foods and Beverages (Hong Kong) Purple Rice and Oats, which is naturally rich in fiber, with no artificial coloring.