Hue and cry over phytonutrients

Scare stories about sinister synthetic colours and 'evil' E-numbers have regularly haunted the headlines. However, increasing use of natural colours and colouring foodstuffs containing phytonutrients may revive the image of hues that, literally, make meals a feast for the eyes.

The word phyto is Greek for 'plant'. Hundreds of different phytonutrients have been discovered in fruits and vegetables. Phytonutrients are not vitamins or minerals. They are antioxidants that help to protect the body against illness. They give plant foods their flavour and colour; the highest concentrations are often found in skins and stalks.

Food manufacturers extract them for use in a wide range of food and drinks. But there is a difference in the way natural colours and colouring foodstuffs are processed, even though both may have health benefits.

"Natural colours are selectively extracted with solvents which take colour out of a raw material. A colouring foodstuff is derived in a non-selective way; it's a concentrate," explains Paul Collins md of Derby-based GNT, which makes Exberry colouring foodstuffs.

Colouring foodstuffs include fruit and vegetable juices, concentrates and dried, powdered extracts. "They're a healthier way of colouring food because they have a higher level of phytonutrients," says Collins.

Many natural colours have been linked with health benefits in peer-reviewed science papers, says Dr Andrew Kendrick, head of technical for Natracol, the range of natural colours and colouring foodstuffs from Roha.

Kendrick observes: "It was found the proposed active phytonutrients that protected against disease were also recognised as natural colours. The general mechanism is one of 'antioxidant' activity and it's interesting to see how this term has moved more into consumer communications."

Benefits of anthocyanins

The benefits of anthocyanins (red pigments) in vin rouge have been written about extensively as being part of the 'French paradox' - the difference between the actual and predicted incidence of heart disease in France based on risk factors for the condition, such as a relatively high fat diet.

"No single dietary factor can completely explain this observation, but it's been suggested that the antioxidant effect of anthocyanins in red wine is due to protective phytonutrients," says Justine Lord, marketing manager at ingredients supplier Overseal.

Overseal's Nutri-seal range of phytonutrients can be used in a wide range of everyday food and drinks. A tropical orange colour is extracted from carrots and palm oil, which contain carotenoids that have vitamin A. Nutri-seal's lime green is sourced from spinach which contains chlorophyll and lutein, known for their detoxifying and wound healing properties.

Analyst Frost & Sullivan says the use of colouring foodstuffs will be boosted by growth in the functional foods and beverages market because they complement a product's healthy image. It estimates the sector is expanding by 10-15% a year.

Lord says: "As part of today's busy lifestyles, functional foods are seen as a way of topping up your diet and receiving a better balance of nutrients that the body requires. Eating functional foods with a variety of different colours that are sourced from nature is just one way you can help to ensure you receive a balance of phytonutrients."

Many phytonutrients are thought to be destroyed or removed by modern food processing techniques and cooking. Consequently, consumers believe industrially processed foods contain fewer phytonutrients than unprocessed foods. But manufacturers say processes have become more sophisticated and help to retain nutrients.

"All the advances in natural colour technology that have been developed over the last 20 years to ensure natural colours deliver vibrant, stable colours will also ensure that the health-giving antioxidant activity is preserved," says Kendrick.

However, Collins argues: "Phytonutrients are sensitive to heat. No functional additive will make them more heat stable. It's a question of working with a manufacturer to minimise the effect of heat. No natural substance can withstand heat fully. You can add it towards the end of the manufacturing process to minimise nutrient loss, but it's not always that easy."

GNT's phytonutrients are used in a range of products, such as drinks, dairy, glazes, seasonings and marinades. Collins says GNT would not make a colour if the process involved in extracting it changed its nature.

Anu Arola, category marketing manager at Sensient Food Colours Europe, notes there are still some challenges to overcome with using colouring foodstuffs in a wider range of food and drink. "There are still some technological barriers depending on the source of the colouring foodstuff and the nature of the pigment," she says. "These include the stability of anthocyanin-based red colouring foodstuffs at higher temperatures and the oxidation stability of turmeric root, or carrot and paprika-based colouring foodstuffs."

Arola says Sensient has spent decades working on developing more stable products that retain the special properties of colours. Its colourings can be used in applications ranging from sweets and dairy to drinks and meats.

Tomato lycopene is an exception to the heat rule. This phytonutrient is concentrated in processed foods such as tinned tomatoes, spaghetti sauce and ketchup, making them better sources of lycopene than fresh tomatoes.

LycoRed in Israel specialises in natural colours derived from lycopene, betacarotene and lutein in a host of produce; and for uses including beverages, salsa, processed meats and surimi, a fish pulp that is formed into different shapes to imitate other seafood.

Udi Alroy, LycoRed's marketing director, says the colourants are available in oil-resistant formulations that protect the tiny carotenoid crystals from dissolving in oil. "For example, Tomat-O-Red can be used to colour fat-containing products like processed meats."

European regulations

Tomato lycopene is approved under EU law, where natural and artificial food colourings are represented by the letter E and a number. An E-number means they have been tested for safety and passed for use, regardless of their source. Colouring foodstuffs are ingredients and are not assigned E-numbers.

In December, the European Food Safety Authority (EFSA) requested data on colours from the industry as part of a routine review of all authorised food additives in the EU. Some 45 approved colours will be reassessed by the EFSA in the next few months.

The EU wants information on safety data that was not considered in original reviews, information on uses in foods, on the purity of colours and production methods.

It is not possible to make health claims about any colours under current regulations, even though much has been documented about the benefits of the phytonutrients in some, including tomato lycopene. Part of the problem is that much of the data in the scientific press is often based on work completed in test tubes, explains Kendrick. It has not been transferred to human clinical trials for validation.

Alroy says it is a different story across the Atlantic: "In the US, where tomato lycopene is an approved colour additive, functional claims are allowed on products that contain it."

Like other companies, Sensient is cautious about making claims about product performance. "We are investigating what possibilities there may be in the future to make claims about health benefits. All the ingredients in the final product, not just the natural colour or colouring foodstuff, should be considered to make a proper claim," says Arola.

Overall, consumer demand for shades derived only from plant sources will help to shape industry developments. For example, there has already been a swing away from carmine-based colours - carmine is a bright red natural pigment derived from the cochineal insect. This shift has led to greater use of anthocyanins and beetroot-based shades.

Kendal believes there will be a gradual removal of artificial colours from products and more natural colours in new ones, although synthetics won't be replaced entirely.

Ultimately, colour specialists must continue to respond to the move towards less additives in food. "We'll see a stricter definition of 'natural' than previously applied," Collins says. Consumers will demand nothing less. FM

The healthy trinity

There are three main groups of phytonutrients: terpenoids, flavanoids and phenolic and polyphenolic compounds.

• Terpenoids include carotenoids and plant sterols, which help protect against heart disease and cancer.
• Fruits are rich in flavanoids that include flavanols such as quercetin, which can be found in grapes, grapefruits and strawberries. Quercetin helps to reduce the risk of heart disease and stroke.
• Phenolic and polyphenolic compounds include compounds that contain glucosinolates which protect against heart disease and bowel cancer. Cabbage and broccoli have large amounts of glucosinolates.

The pigments

Anthocyanins:​ part of the flavonoid group, they are responsible for the red and purple pigments found in fruit and vegetables. Anthocyanins put the 'blue' in blueberry and are the healthy part of red wine.

Betacarotene:​ a carotenoid that can be converted into vitamin A, which is vital for healthy vision, skin and growth. It is found in carrots, papaya and mango.

Curcumin:​ a pigment of turmeric; may protect against intestinal cancer and help to lower cholesterol. Ginger also contains curcumin.

Chlorophyll:​ a green pigment that aids wound detoxification.

Lutein:​ a carotenoid that may help prevent age-related macular degeneration, a leading cause of blindness.

Lycopene:​ another carotenoid with strong antioxidant properties; may help to prevent prostate cancer. Tomatoes have high levels of lycopene.