A food’s appearance may well be its most important characteristic. After all, a product’s taste or nutritional benefits will be of little value, if a consumer does not want to even taste the product.

Colorings may be added for functional reasons--to help protect nutrients, for example. However, they primarily are used to improve a product’s attractiveness and to communicate certain product characteristics to consumers. For instance, through its use of Yellow 5 Lake and Blue 1 Lake colors, Kraft Foods’ Nabisco Oreo Cool Mint Double Stuf cookies signal to customers that they definitely have a cool mint flavor. CandyRific’s Lite-Up Cool Pops Flower Power candy attracts kids with turmeric root extract and anthocyanin colorings. (A package that is a battery-powered fan helps as well). Similarly, lycopene helps color Kalona Organics Strawberry yogurt, while Red 40 gives Lucerne Foods’ Watermelon Flavored applesauce an eye-catching red.

Making a Colorful Appeal

Colorings can send subtle messages about a product. “Traditionally, consumers often considered foods with brown and earthy tones as ‘healthy,’ with the lack of vibrant colors signifying ‘natural,’” says Anju Holay, of Barrington, Ill.-based Next Step Marketing Research. “However, consumers in our more recent focus groups tell us that ‘healthy’ may now include a broader spectrum of color, as long as the product also delivers a better nutritional profile and superior taste.Formulating products to meet these evolving consumer perceptions is a fertile area for future sales growth,” she adds.

Consumers “expect” certain colors, and their expectations stem from purchasing consistent products (a quality control issue) and their own experiences. The failure of Crystal Pepsi, a clear cola introduced in the early 1990s as part of the fad in non-colored beverages, is one example. “In consumers’ minds, a clear beverage was a disconnect from what a cola is supposed to be,” says Lynn Dornblaser, director, Custom Solutions Group, Mintel International. “It’s good to experiment, but you can’t formulate a product too far outside consumers’ comfort zone. Purple mashed potatoes work only for eight-year-olds.”

 Colorings also can be used to mask natural variations; however, care should be taken in choosing the colorings, based on the degree of formulation flexibility allowed. For example, this author had to troubleshoot a QC issue years ago, when consumers complained that the company’s coleslaw varied significantly in color from batch to batch. The batch formula called for a minor amount of FD&C-certified blue and yellow colors to enhance the salad’s natural green color. It was discovered that production personnel were altering the amount of added certified coloring in each batch, to adjust for natural variations in the green cabbage leaves. By the end of the product’s shelflife, however, the chlorophyll had faded, leaving coleslaws of widely varying greens. This happened because only the more stable certified colors, which had been formulated differently batch-by-batch, remained.

Many products have achieved commercial success based--in great part--on the careful choice of color additives; however, understanding colorant properties is often key to creating clever, novelty versions of high-quality favorites.

Color Tricks to Stability Tactics

Certified colors are categorized as either “dyes” or “lakes.” Dyes are water-soluble, whereas lakes are the insoluble form of the dye. Lakes are appropriate for fats and oils and other products with little moisture; they are dispersed, rather than dissolved in oil.

According to one video clip on a supplier’s website, dyes display color in solution when white light (i.e., all the colors of the spectrum) penetrates the liquid and is partially absorbed, resulting in color. Lakes, on the other hand, absorb and reflect light. “Lakes determine the shade of dry mixture; once in contact with water, the soluble dye dominates,” notes the clip. Some confectionery companies have taken advantage of these differing properties to create products that change color when placed in the mouth. Here, lakes and dyes are combined in a food that contains no water. That is, the phenomena can occur in a hard candy, such as a SweeTart, but not in a gummy-type candy. Lakes provide the color of the dried product (before eating); then, the color of the dye dominates as it dissolves in saliva.

Dyes and lakes also differ in their stability; that is, dyes tend to resist fading more than lakes. Indeed, color stability is a key challenge in working with coloring additives. Although exempt from certification color additives (often referred to as “natural coloring”) are generally less stable than certified ones, all are positively and negatively influenced by light, pH, moisture, temperature conditions and the presence of other ingredients.

“Generally, we tend to use FD&C colors in the products that we formulate,” says Mark Black, principal scientist with Plymouth, Minn.-based Merlin Development. “The ‘naturals’ tend to fade…a lot.”

Merlin Development’s clients do, in fact, usually first ask for natural colorings, but then must face certain realities. “Our client may have a beverage in the pH range of 3-4. Our ingredient suppliers tell us that under those conditions, the product’s shelflife would be only three to six months, and even then, there will be some fading,” says Black. This compares to a six-to-12 month shelflife, if FD&Cs are used. “Although,” he adds, “even with certified colors, that may be stretching it for some products.”

“We’ve done enough work with the FD&Cs that we’ve learned we must test a product’s shelflife under different lighting conditions,” says Black. For example, florescent lights are very hard on Red 3, while Red 40 tends to be a bit more stable. “It’s always best to test under whatever conditions the product will likely be stored.”

The pH of a product can have unexpected consequences. For example, Black notes that in work with FD&C colorings, a solution would be formulated to an exact color wanted, such as purple or green. “Then, we’d drop the solution’s pH in the next set of trials, and a huge color change would occur; the color would be far more intense,” he relates. In order to get back to the original desired color, the percent of color had to be roughly reduced by an order of one magnitude for a change of every one pH unit in this particular product. “It appeared that we were getting different degrees of color dissolution at different pH levels, even though the colors looked thoroughly dissolved,” says Black.

A change in pH can impact color intensity, as well as hue. For example, anthocyanins, key colorants of blood oranges, red grapes and blueberries, function as natural pH indicators, moving from red to purple to blue; this depends on the pH level and the specific anthocyanins under consideration.

An example of this is demonstrated when a few drops of grape juice are emptied into a sink. As the water dilutes the juice, pH increases and the color changes.

In processed foods, a pH change can be an issue with products containing fermentation or other types of live organisms (for example, yogurt-based drinks). In some cases, the organisms may even break down natural colorings.

“Natural colorings are not only less stable and a great deal more expensive than certified colorings, but, depending on regulations, you may not even be able to label them as ‘natural’ on the label, but rather ‘artificial’ or by the specific colorant,” says Black. For example, a beet-derived coloring or carmine is not “natural” to a strawberry yogurt. “It can be a challenge to explain this to a client,” he adds.

The industry does continue to look for natural colorants, due to greater consumer appeal and the less-than-positive news in recent months about FD&C colors. Suppliers are working to enhance the stability of their natural colorings, and processors have other options, also. Examples include the addition of antioxidants. “This is particularly helpful for the yellow, orange to red carotenoid colorings,” says Black. Additionally, “Packaging that reduces exposure to light, that excludes oxygen and/or that keep it to low levels helps retard oxidation of certain pigments,” offers Aaron Brody, president and CEO, Packaging/Brody Inc.

Not all naturals are particularly sensitive. “The caramel colors tend not to fade so much,” says Black, “but you need to work to select the right one for a particular application.” Depending on several factors, including how they were processed, caramels have a huge range in hues.

In the end, colorants contribute much to product desirability, but obtaining just the right, bright color in products with long shelflives will remain a challenge.pf

Website Resources:

www.sensient-fce.com -- Video clips on various aspects of colorings
www.ific.org/publications/brochures/foodingredandcolorsbroch.cfm#FDA -- Article titled, “Food Ingredients and Colors”
www.foodsafety.gov/~lrd/colorfac.html -- FDA statement on certified food colorings
www.cfsan.fda.gov/~dms/col-toc.html -- FDA’s color additives website, covering history, regulations, the petition process, compliance resources, etc.