Going Au Naturel: Coloring Considerations

November 25, 2014, Global Food Forums — The following is an excerpt from the Ingredion-sponsored “2013 Clean Label Conference Report.” 

Basic Chemical Structure of Anthyocyanins

Click on image for full-size PDF.

Neither FDA nor the EU has a legal definition of “natural” colorants; however, consumers and marketing departments seem to have a clear concept, wryly noted Ronald Wrolstad, Ph.D., Distinguished Professor of Food Science Emeritus, Oregon State University.

FDA classifies colors as either certified, synthetic FD&C food dyes or as color additives for food use that are exempt from certification. Most of those exempt from certification are naturally derived. “The Southampton Study,” which several years ago assessed the effects of synthetic food colorant consumption on 3-year-old and 8-to-9-year-old children’s hyperactivity levels, concluded that the Global Hyperactivity Aggregate (GHA) score was higher due to synthetic color consumption. However, the FDA took no action, and the EFSA concluded that the Acceptable Daily Intake should not be changed.

Yet, partially due to that study, global sales of ‘natural’ colorants have overtaken artificial,” said Wrolstad. While providing cleaner labels and health benefits, there are obstacles to using “natural” colorants. Typically less stable to heat, light and oxygen, they may also react with other components in formulations producing undesirable flavors and colors. All desired hues may not be possible, and natural colors are more costly.

“The ideal natural colorant,” explained Wrolstad, would be permitted for use in all markets and have no negative impact on product appearance or flavor. Also desired are no changes to nutritional profile, shelflife or stability; or to the manufacturing process, packaging or ingredient cost. In the real world, there is no global consensus on regulations.

When replacing synthetic colors with natural ones, matching appearance is challenging, he added. Flavor profiles often change, and color is usually less stable—often causing processing and packaging changes and cost increases. Alternatives to artificial dyes include anthocyanin-based colorants. In the U.S., these include fruit and vegetable juices and have an E163 designation in Europe. Structure variation of a compound impacts hue and stability. They are reddish in acidic solutions and more purple nearer a neutral pH. Betalain pigments are prominent in beet powder and beet juice. They have been found suitable for frozen desserts, for example.

Cochineal and carmine, which are extracts of insects (Dactylopius coccus), are extremely stable to light, heat and oxidation, but they are more expensive and are non-kosher. Tomato lycopene extract is water-insoluble, available in oleoresins, powders and water-dispersible preparations. Tomato lycopene extracts range from yellow to orange to red hues and are stable through a broad pH range, but are also susceptible to oxidation.

Carotenoids provide natural yellow and orange hues. They are lipid-soluble and susceptible to oxidation. Annatto is available in water- and lipid-dispersible preparations and provides yellow to orange colorings. Turmeric is a spice-giving characteristic color and flavor to mustard, pickles and curry powder. It is unstable to light and susceptible to oxidation.

Clinical research has looked at tumeric’s potential health benefits in kidney and cardiovascular diseases, certain cancers and arthritis, among other health conditions. (See http://ow.ly/stpFa.)

Saffron provides an intense yellow pigment. It is derived from the stigma of Crocus sativus flowers and is relatively stable to light and heat, but it is very expensive, warned Wrolstad. For green hues, chlorophyll [sodium copper chlorophyllin] is approved in the U.S. for citrus-based, dry-mix beverages but is used widely in the EU.

When it comes to blues, there are limited options. Spirulina extract is the blue water extract of cyanobacteria of the Arthrospira genus and has been approved for confections and chewing gum.

Caramel colorants are generally manufactured via the Maillard reaction. They are water-soluble and range from amber to reddish-brown to dark brown. Preparations are available for soft drinks and alcoholic beverages. Carbon black has been delisted in the U.S., but is permitted in the EU. Titanium dioxide is a permitted whitening agent in confectionary, baked goods and dairy products.

Differences may occur between suppliers. A colorant can vary in price, purity, tinctorial strength, shade, the presence of unwanted flavors, stability to heat and light, tendency to precipitate and suitability for individual applications. On the horizon are new sources of edible plants with high pigment content, desirable hues and good stability.

Ronald Wrolstad, Ph.D., Distinguished Professor of Food Science Emeritus, Oregon State University, http://oregonstate.edu/foodsci/

Posted on:November 25, 2014

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