Alternative red hue from purple sweet potato

The company said the new product is an anthocyanin colorant, where the pigment is extracted from a fruit or vegetable source.

It provides a red hue in acidic conditions and potential application include beverages, sherbet, salad dressings, fruit preparations and sauces.

It echoes a trend among both consumers and manufacturers for natural alternatives to synthetic food colors, partly due to health concerns, and a growing desire for "natural" products.

DD Williamson said food and beverage processors in the US who use the purple sweet potato can boast of their product being "colored with vegetable juice" or "vegetable juice color" as part of their ingredients statement on the label.

Campbell Barnum, global vice president, branding & market development at DD Williamson, told FoodNavigator-USA.com: "Our testing shows that purple sweet potato has good stability properties compared to alternative anthocyanin sources.

"From a processing and shelf-life perspective, vegetable-based coloring is usually more stable than fruit-based coloring.

"In the US, processors can declare "vegetable juice for color" on a product label.

"Consumers are concerned with health and wellness; therefore, tomato juice and blends are popular in the U.S. market."

The product offers an alternative red when formulating new foods and beverages.

The hue of anthocyanin is pH sensitive.

At pH 3.0 (acidic), anthocyanins appear red or reddish-orange in solution but as the pH increases, the hue becomes more purple.

DD Williamson Barnum claims DD Williamson is the world leader in caramel color, which is naturally-derived from corn syrup, cane sugar, etc, but it continues to grow in other naturally-derived colors.

He added: "In the past few years, we have expanded our coloring portfolio through both acquisition and innovation.

"In June, the Center for Science in the Public Interest petitioned the FDA (US Food and Drug Administration) to revoke the approval of most synthetic color additives, and we continue to see food and beverage developers increase their formulation of non-synthetic (non-certified) colorants to enhance visual appeal of their products."

Purple sweet potato is a non-synthetic (non-certified) coloring and is currently available as a liquid.

However, DD Williamson said they may consider a powder version.

Natural and synthetic colors Various published studies have caused many consumers to be concerned about the consumption of synthetic color additives, according to industry experts.

Anthocyanins are the source of the blue, purple and red color of berries, grapes and some other fruits and vegetables.

These pigments also function as antioxidants, believed to protect the human body from oxidative damage that may lead to heart disease, cancer and ageing.

Pigments from red beetroots are seen by some as potential rivals to the more established anthocyanins.

The main betacyanin compound found in red beetroots is betanin.

However, the red beet had several disadvantages, including unfavourable flavour components, no nitrate accumulation, and the risk of microbe carry-over from the earth.

Recently a study, published in the journal Food Research International looked at the pigment stability and colour of betacyanins extracted from the purple pitaya, a fruit reportedly attracting interest as an alternative to red beet.