Formulating with Natural Colorings
Exempt natural and nature-identical colors can be found listed in 21 CFR 73, as approved for food, drugs, cosmetics and medical devices. Natural color sources are also used as natural flavors, juice concentrates, antioxidants, dietary supplements, spices and extracts.
In a presentation titled, "Natural and Nature Identical Colors," given at Prepared Foods' R&D Applications Seminars-Chicago, Leslie Lynch, sales manager, Food Ingredient Solutions LLC, discussed a number of options available to formulators of foods, including beverages, as follows.
Anthocyanins are derived from red cabbage, purple sweet potato, black carrots, red radishes, elderberry, grape juice and grape skin extract, and purple corn. Noted properties of anthocyanins include their color change with pH change. They are more reddish at low pH values and more bluish at neutral pH. As pH increases, they are less stable, which is especially evident in high water activity systems. In the presence of positive metal ions, like calcium, iron and zinc, their color also fades.
Anthocyanins are also sensitive to ascorbic acid, especially above 100ppm. However, levels of 50-70ppm ascorbic acid appear to stabilize anthocyanin-based colors. These colored compounds offer a range of shades and stabilities. "Anthocyanins are generally used in acidic products, like beverages, fruit preparations, frozen desserts and candies, as a primary color or a secondary color for shade adjustment or masking," states Lynch.
Carotenoids are sourced from algae, annatto, carrots, gardenia, marigold, palm, oleoresin paprika, saffron and tomatoes, and through synthetic production of apo-carotenal beta-carotene, canthanxanthin and lycopene. Carotenoids typically exhibit good heat stability and fair light stability. Stability to light and heat can be improved with the addition of 200-500ppm ascorbic acid. Also, some carotenoids bind with protein for better stability. On the other hand, it is best to avoid use of the emulsifier polysorbate 80.
Applications for carotenoids include oil-based products, like icings, popcorn oils, margarine, dressings and sauces, and water-based products, such as ice cream, cheese, beverages, puddings, yogurts, ice cream cones, seasonings, snack foods, baked goods, tomato-based products, surimi and confections.
Betalains from red beets provide a pink to fuchsia color, but exhibit poor heat and light stability. They are relatively inexpensive for use in ice cream, frozen desserts, yogurt, cold extruded meal bars, tablets, powdered beverages and meat analogs. Novel applications are for panned confections and cocoa or tomato sauce, where browning is desirable.
Anthraquinones are available through cochineal, kermes and lac insects. Carmine (the calcium aluminum lake of cochineal) and cochineal extract are approved for use in food and are widely used in fruit preparations, confections, beverages, cherries, meal replacement bars, meats, sausage casings, pastas and surimi. Anthraquinones are available in orange to red to purple shades. They can be combined with pearl luster pigments; protein-free versions (i.e., less than 0.5% protein) and micronized versions are commercially available.
Curcumin and turmeric come from the root of the Curcuma longa plant. Pale to bright yellow, with excellent heat stability but poor light stability, applications include pickles, spices and seasoning blends, ice cream, yogurts, dietary supplements, vegetable relishes and mustard.
Copper chlorophyllin from alfalfa is approved for use as a color in dentrifices and powdered citrus beverages. Lynch notes that Food Ingredient Solutions petitioned FDA for all food uses, which has been pending since October 2006. They expect approval in 2011. Alfalfa extract is only permitted as a natural flavor and cannot be used as a color. An olive to yellow-green shade, it is not affected by pH, is fairly heat- and light-stable, but is not acid-stable.
Carotenoid Coloration Workshop
Another presentation given at the 2009 Prepared Foods' R&D Application Seminars-Chicago went into greater detail on the uses and benefits of carotenoid colorings.
Over 600 carotenoids have been identified in nature. They are the pigments that give autumn tree leaves, tomatoes, peppers, corn, oranges and lobsters their distinctive color. They all have coloring effects, but not all carotenoids have pro-vitamin A activity, noted Gus Castro, senior technical marketing manager, DSM.
For example,ß-carotene has dual regulatory status as a color or a vitamin A source. It is commercially available in both natural and synthetic product forms; when highly purified, its crystalline forms are functionally and chemically alike. However, ß-apo-8'-carotenal (Apo) and its ester form, as well as canthaxanthin, are allowed within the regulations for color only. Lycopene, lutein and zeaxanthin are allowed in foods for nutrient fortification only; astaxanthin is only allowed in animal feed. The three main carotenoids for discussion here are ß-carotene, ß-apo-8'-carotenal and canthaxanthin, noted Castro.
Carotenoids are highly unsaturated (they have many double bonds), and their molecular structures have relatively long chains. These characteristics are important, because they influence the color, chemical stability and solubility of the carotenoids.
Carotenoid crystals are very unstable and prone to oxidation, and they are water-insoluble and very slightly soluble in oil. Due to their inherent instability, market forms of the ingredients have been formulated to broaden their applications, remaining more stable to oxygen, heat and light, and metals, like iron and copper. The three basic commercial forms are water-dispersible powders, oil blends and emulsions.
Water-dispersible market forms are used in foods with water as the major component, such as ready-to-drink beverages, juices and ice pops. They also work well in powdered foods that are typically reconstituted in water, like instant beverages and cake mixes, where carotenoids are dry-blended with other ingredients, said Castro.
Oil-based market forms are suspensions of crystals and solutions with fully dissolved crystals and used in foods where fat or oil is the major component. For margarines, salad dressings, frostings or baking fats, ß-carotene in suspension is a good choice. Salad dressings and cheese can also benefit from a suspension of ß-apo-8'-carotenal. Solutions of ß-apo-8'-carotenal alone or with ß-carotene can also be of benefit in process cheese and salad dressings.
The preparation and use of a carotenoid stock solution can be convenient for an R&D lab or in a production environment, when small levels of coloring are needed. Stock solution usage allows the precise volumetric addition of color and simplifies plant scale-up.
Stock solutions can be made to almost any concentration. However, the most convenient is at 1mg total carotenoid per ml. According to Castro, "Carotenoid suspensions must be well-mixed before using, as the carotenoid crystals, which are denser than oil, will settle." Good-quality oil should always be used when making an oily stock solution, in order to minimize oxidation of the carotenoid. They are heated and vigorously mixed at 60-65∞C to dissolve the crystals, while minimizing air incorporation. Powders in stock solutions ideally use demineralized water at 45-50∞C, where powders are slowly added to the water with constant mixing, avoiding foaming. Stock solutions may prudently be stored under refrigeration for 24 hours.
Typical use rates for ß-carotene in beverages depend on desired color, usually between 1-15mg per quart. Canthaxanthin would be used at 3-15mg per quart. For example, a typical fruit punch would use 8mg pure canthaxanthin per quart. Castro adds that other applications include baked goods, non-dairy creamers, whipped toppings, ice cream, soups and sauces, egg products and frozen meals. Carotenoids provide clean and beneficial labeling with some nutritional advantages.
"Carotenoid Coloration Workshop," Gus Castro, senior technical marketing manager, DSM Nutritional Products Inc., www.dsm.com/en
--Summary by Elizabeth Mannie, Contributing Editor
Coloring Perception and Choice
In today's market, consumers are increasingly looking for products that contain natural, easily recognized ingredients, said Stefan Hake, CEO of GNT USA, during a presentation titled, "Colors and Perception." The 2007 publication of the "Southampton Study," a UK study that provided evidence of a potential link between common synthetic food dyes, the preservative sodium benzoate and hyperactivity in children, added fuel to the already heated debate over the human health impacts of consuming artificial food dyes and other artificial additives. As a result, the European Commission ordered all food and beverages containing any of the synthetic dyes in the study must carry warning labels, as of July 2010.
U.S. consumers are also demanding healthier foods and beverages with fewer ingredients and artificial additives. Also important, natural colors are required, in order to be accepted by retailers, such as Trader Joe's and Whole Foods.
Using the right natural colorant can make a huge difference in label appeal, performance and consumer perception. According to Hake, "Fruit and vegetable juices used for color can provide a spectrum of shades as diverse as FD&C colors."
In order to determine the right natural color ingredient, several considerations must be addressed. In addition to the flavor of the product, an understanding of the marketing strategy is extremely important. Other important considerations include physical form, packaging, shelflife and regulatory restrictions where the product is being sold.
Acids should be added first, when working with anthocyanin colors, which are pH-dependent. A pH of 4.0 or less yields red color shades, while a pH of 4.0 or higher will result in more blue-indigo shades. Carotenoid products are pH-independent. When working with carotenoids, use a deionized water and buffer to the pH of the application.
Stability of natural colors ranges from 3-12 months, depending on packaging, processing, application, heat or light exposure. Accelerated shelflife studies and color-stability analyses help achieve optimum color performance.
Processing considerations include pasteurization, HTST, UHT or hot fill. Color dosage may be increased by 10-20%, if required after processing. Working closely with the supplier can be instrumental to understanding special processing considerations.
Beverage stability can be impacted by the base of the beverage application, pH and fruit content. The base color is key to understanding the color dosage required. It is also important to consider potential ingredient interactions that could impact color, such as vitamin C. Other factors that could impact beverage stability include whether it is refrigerated or shelf-stable, and type of packaging.
In dairy applications (such as yogurt), fat, pH and style should all be considered, when choosing the appropriate natural color. In fruit preparations for yogurt, color can be impacted by cook time, order of ingredient addition and timing of color addition. Possible ingredient interactions include anthocyanins with vitamin C.
For hard or gummy candies, the type of sugar being used, processing method and temperature at which the color is added can all impact the final color in the application. Fat content can also interact with color, changing orange to yellow. Temperature, beating or pulling time can all impact final color.
Most importantly, in order to achieve optimal color results, it is important to work closely with the supplier. Understanding supplier capabilities and resources at early stages and implementing the appropriate color strategy will ensure the development of a high-quality and colorful product.
Stability of Natural Colors for Beverages
A growing trend toward use of naturally derived colors in foods and beverages is in part due to a study commissioned in the UK by the Food Standards Agency (FSA) in 2007 that assessed the effects of consumption of synthetic dyes on children's behavior. In the "Southampton University Study," children were given a mixture of synthetic dyes with the addition of sodium benzoate. Researchers observed increases in children's hyperactivity levels, after they consumed the beverages. The methodology and conclusions of the study were questioned; however, the results had worldwide repercussions, raising awareness of the safety and possible effects of these dyes, said Jody Renner-Nantz, food science chemist, D.D. Williamson, during her presentation, "Research on Heat and Light Stability of Naturally Derived Coloring for Beverages," at the 2009 Prepared Foods' R&D Applications Seminars-Chicago.
Because of this study, the European Parliament voted to label foods containing these colors with: "may have an adverse effect on activity and attention in children." This created, in effect, a ban on the European equivalent of red 40 and yellow 5 and 6 in the EU. Food scientists, feeling the pressure of that study, as well as the trend toward healthier eating, rushed to reformulate by substituting naturally derived colors for synthetic dyes.
Beverages are one large sector using naturally derived colors. Teas are very popular, partly due to their naturally high antioxidant content. "Now, teas are seen with added naturally derived color, such as elderberry or hibiscus extracts, adding appeal to the products," stated Renner-Nantz. "Teas and other ready-to-drink beverages usually command a prime spot in the grocery store, making them more susceptible to color degradation by light," she added.
Fruit smoothies and other refrigerated beverages often contain betalains--a group of pigments derived from beets, with magenta red hues. In contrast with anthocyanins, betalains have poor heat and light stability, which is why they are typically used only in refrigerated, dairy-type beverages, where they are protected from light.
Anthocyanins have improved heat and light stability over betalains. Ubiquitous in nature, anthocyanins are derived from fruits, vegetables, starchy legumes, grasses and flowers. Over 600 different anthocyanins have been isolated from plants. Most plants contain not just one anthocyanin, but many.
Anthocyanins have the highest stability at pH 3.0. At pH 4.5, the resonance structure of the molecule breaks, causing a dramatic decrease in color intensity, where the hue begins to change toward purple. As pH increases, the hue gets bluer. This change is reversible, however. If kept at higher pH, anthocyanins begin to degrade and turn gray, such as in milk-type beverages, Renner-Nantz said.
Anthocyanins can be subdivided into two groups: acylated or non-acylated pigments. Acyl groups (phenolic or aliphatic groups) are thought to protect the flavylium cation center core of the anthocyanin molecule, by forming a sandwich structure around it through intramolecular bonding. Typical sources of acylated anthocyanins are purple carrot, purple sweet potato and red cabbage. Non-acylated anthocyanins are often derived from fruits.
The degree of acylation determines stability. For example, red cabbage and purple sweet potato anthocyanins are highly acylated and, therefore, more heat- and light-stable, while anthocyanins from fruits like elderberry are non-acylated and less stable. Interestingly, grape skin extract has both types; however, many times, grape skin anthocyanins are associated with tannins that can cause browning and precipitation during storage, especially evident at pH 3.5.
Other factors affecting anthocyanin stability include vitamin C, trace metals and minerals. Anthocyanins are recommended for use between pH 2.5-3.5. D.D. Williamson's research shows purple carrot maintains a reddish hue over a wider pH range than other anthocyanins, making it a great choice for yogurts.
To optimize color, formulators often need to blend both fruit and vegetable anthocyanins. This is where a coloring supplier should be able to help optimize naturally derived color performance.
"Research on Heat and Light Stability of Naturally Derived Coloring for Beverages," Jody Renner-Nantz, food science chemist, D.D. Williamson, jody.rennernantz@ddwmson, www.ddwilliamson.com
--Summary by Elizabeth Mannie, Cont. Ed.pf