When food color innovation turned decisively toward nature for its sources of desirable pigments, food color technologists worked overtime to develop cost-effective, clean-label colors. Some shades proved an extra challenge, with stability and fixing being major trouble spots. Red colors figured largely in that task.
The color red elicits many emotional responses. It is eye-catching, bold, powerful, and—in some shades—even cheerful or romantic. In foods and beverages, red can communicate intensity of flavor, rich mouthfeel, and high nutritional content. Whether the deep burgundy of a pinot noir, the crimson hue of fresh meat, or the bright scarlet of a cherry confection, shades of red in foods and beverages prime the appetite center in our brain for a dynamic sensory experience.
FD&C-approved synthetic red dyes, such as Red-3 and Red-40, have been used across an immense range of products and applications since the early 1970s. Today, consumers are paying much closer attention to the types of colorants used in foods and beverages, looking for “clean-label” products that are free from artificial additives.
This fundamental shift has translated to a high demand for natural reds, derived from familiar sources such as tomatoes, beets, fruits, sweet potatoes, radish, black carrot, berries, and other botanical sources. Additional natural sources of red pigments, such as carmine, red palm oil, annatto extract, and—more recently—microbially produced red pigments are now popular alternatives to synthetic reds.
In the decision tree of color selection, solubility should always come first. Next, developers should evaluate the food matrix and processing conditions. Undesirable color changes, such as browning or shifts in shade from red to blue or green, can occur in the presence of acidulants, metal ions, oxygen, light, or heat, so developers also should keep in mind processing and final product packaging when selecting reds for their formulations.
Red iron oxide is one of the most stable and reliable alternatives to Red-40. Its natural reds are ideal alternatives to synthetic red due to its stability under various pH, temperature, and light conditions. In 2015, red iron oxide was granted FDA approval for exempt-from-certification status as a food colorant in confections, including chewing gum, mints, and hard and soft candies.
Carmine (carminic acid) is another effective red that can produce shades extending from pale pink to deep ruby across a range of food and beverage applications. Cochineal extract, which contains carminic acid from cochineal scale insects, is water soluble, while carmine is the lake preparation of carminic acid and can be dispersed in lipid phases of food formulations. The one drawback is that, while technically natural, its source is a point of controversy. In fact, carmine’s source also rules out the very important kosher certification.
In selecting red shades for beverages, a variety of plant-based food colorants are effective for delivering desired tones. Water-soluble pigments, including lycopene from tomatoes and anthocyanins from berries and other botanical sources, can provide stable hues that range from deep magenta to eye-catching red-orange. These sources also bolster clean-label appeal.
Red and Wet
Acylated anthocyanins are an example of a promising alternative to synthetic red food dyes. Natural sources of acylated anthocyanins include radishes, red potatoes, red cabbage, black carrots, and purple sweet potatoes. Diacylated anthocyanins are ideal red coloring options for beverages with pH values below 3.5. In higher-pH beverages and other applications, beet juice, which contains betalain pigments, can also produce desirable shades ranging from light pink to deep vermilion.
Betalains can deteriorate in the presence of heat and light, however. In foods where high temperatures and translucent final packaging are used, carminic acid, carmine, or red potato extract may be more suitable options. Beet juice tends to perform best in bakery products and low-moisture snacks.
Lipids also have an effect on colorants. In high-fat-content applications, such as seasonings, cheeses, crackers, plant-based dairy alternatives, ice cream, and bakery products, annatto extract is an excellent natural red candidate. Derived from the seeds of the achiote tree (Bixa orellana) and rich in vitamin A as well as the powerful antioxidant form of vitamin E, tocotrienol, annatto extract has a yellow-orange hue that can be combined with other natural red pigments to produce a range of desirable hues that can indicate savory flavor profiles such as cheesiness, spiciness, and smokiness.
Complex food matrices, such as dairy products and plant-based meats, also benefit from natural reds. These formulations require a pigment that can remain stable throughout shelf life in low-temperature and relatively low-acid conditions. Fruit-flavored dairy products such as yogurt, kefir, and ice cream all benefit from fruit and vegetable-derived red pigments. Moreover, colorant technology has opened the door to a number of such natural options that avoid past tendencies to “bleed” into the surrounding matrix in layered formulations.
In plant-based meat alternatives, berry-derived red colorants from pomegranate extract, cherry extract, lycopene, and other plant sources can impart the appetizing bright-red shade of fresh meat. Importantly, these pigments remain stable during heat processing. Natural brown colorants, such as those from apple extract, are sometimes used in combination with natural reds to produce a realistic meat analog that changes color upon cooking, yielding the desirable rusty-brown color that consumers associate with cooked meat.
To further serve consumers’ interest in health and wellness, brands and developers are also leveraging the use of natural reds that also carry health-promoting properties. Red palm oil, for example, is derived from the palm berry fruit that grows on oil palm trees (Elaeis guineensis).
As with annatto, red palm oil is rich in compounds of vitamin A and vitamin E, including beta-carotene, tocopherols, and tocotrienols, all of which reflect wavelengths in the red, orange, and yellow portions of the visible light spectrum. These compounds offer potent antioxidant, neuroprotective, and other healthful properties.
Red palm oil can be used as a natural red coloring agent in oil-based foods such as sauces, dips, dressings, and confections. Because controversy surrounding sourcing of palm oil exists, brands and manufacturers should strive to source this ingredient from sustainable sources that do not promote deforestation and natural habitat destruction.
Today, consumers are enticed not only by clean ingredient lines, but also by bright, vibrant, eye-catching colors. Various shades of red can communicate exciting sensory experiences that the adventurous are seeking. A bright red-orange seasoning on the surface of a chip cues a red-hot flavor and mouthfeel, while the pale lavender or cheerful pink of a berry-flavored kefir cues a mouthwatering fruity flavor.
As consumers seek more novelty and innovation when it comes to foods, shades of red may be utilized in more unexpected ways, such as in a pizza-flavored seasoning on popcorn, or in a coated red-velvet ice cream bar. In order to achieve a comprehensive array of red shades, developers can formulate with more than one source, plus other natural colors, such as greens, blues, and browns. Working together, product developers and colorant technologists can pinpoint the ideal color system for their formulation by evaluating the characteristics of the food matrix, color solubility, and processing and storage conditions.
Developers can work with color manufacturers and suppliers to find just the right blush of red desired for their formulations. Many of today’s suppliers offer natural pigments that have been carefully designed to ensure their stability and attractiveness throughout all processing, storage, and display conditions.
Regular contributor Olivia Conrad is a product development scientist for Simply Good Foods Co. is a freelance science writer based in Boulder, Colorado. Holding a food science degree from the University of Maine, she has extensive experience in natural foods product development in categories ranging from frozen desserts to meat snacks. She also is an expert in food safety with a strong working knowledge of FSMA and HACCP principles. She may be contacted at firstname.lastname@example.org.
Red pigments produced using biotechnology are now an option for product developers. “The FDA already has approved beta-carotene from Blakslea trispora and Dunaliella salina,” notes Upasana Hariram, MS, a product manager for the food safety consulting company Merieux Nutrisciences, a division of the Institut Mérieux. “There are approved microbial pigments such as astaxanthin, a pigment produced by microalgae, and prodigiosin is a red pigment applied in yogurt and beverages and produced by different strains of the bacteria Serratia marcescens.”
Producing food colors using fermentation has significant benefits, as it allows for a high level of precision and control of production conditions. “The growth of microorganisms is scalable and does not depend on seasonal availability,” explains Hariram. “Techniques in genetic engineering can be used to develop strains with highest yield and desirable properties of the pigment.”
She adds, “Many of the pigments produced from microorganisms not only have an application as a coloring agent but also have other beneficial properties, such as antioxidant, antimicrobial, and anti-inflammatory capacities.” Other red pigments produced using microorganisms and boasting great potential, according to Hariram, include phycoerythrin (derived from algae and cyanobacteria), rubrolone (from Streptomyces echinoruber), anthraquinones (from Penicillium oxalicum), and lycopene (from Fusarium sporotrichioides and Blakeslea trispora).