The trouble with nature...

By Rod Addy

- Last updated on GMT

Related tags: Food coloring

Natural colours: insatiable demand but no silver bullet
Natural colours: insatiable demand but no silver bullet
As the food industry shifts from synthetically-derived colours, past ‘natural’ ingredients to colouring foodstuffs, we highlight the challenges this is currently creating.

If God had meant us to fly he would have given us wings. It's a phrase heard sporadically from the lips of reactionaries. Fortunately, this attitude hasn't stifled inspiration. As a result, we have Avon cosmetics, iPads and a selection of hot and cold beverages from the buffet car.

People have a lot of leeway to shape their environment hence bright sparks in the food industry have produced some of the brightest colours on Earth. But progress rarely charts a straight line. Often there are u-turns along the way as things crop up. In this case, there's the Southampton six colours study, which was published in September 2007.

Together with media coverage and the Food Standards Agency's reaction, the study sent technical scientists scurrying back to white boards to address concerns about how certain colours influenced hyperactivity in children.

Back to basics

The UK food colours industry is still dominated by reformulation issues, as experts return to basics to find 'natural' replacements for synthetically-derived shades. As John Willetts, international sales manager at Univar explains: "It used to be about product creation and formulation. Now it's about problem solving and reformulation."

A gallop through the latest market data confirms the insatiable demand for natural colours. According to Leatherhead Food Research's (LFR's) report The global market for food colours, updated in November 2010, food and beverage colours in 2009 were worth $95M (£59.2M) in the UK. The UK represents the biggest slice more than a quarter of the total European market.

LFR predicts the UK market share for natural colours will grow from 40% to 45% by 2015, reflecting consumer purchases of food free from artificial ingredients and additives, which rose from 18% in 2003 to 25% in 2009.

That said, some experts claim the move to natural has been more prevalent within own-label products as it has been within branded offerings, except in sensitive areas such as children's drinks and confectionery.

"The biggest move is for supermarket own brands,"​ says Willetts. "We have spoken to brands and delivered solutions, but overall they seem to take more of a pragmatic view. If there's lost sales ​[as consumers boycott products] they will switch to natural colours, but many aren't seeing that."

Synthetic falls

In western Europe as a whole, natural and synthetically-derived nature-identical colours have grown in value by 7.5% annually. By contrast, the synthetic colours market has fallen by 2% a year and seems set to lose its current dominance in the next few years.

Innova Market Insights lists the top 10 colours used in new products in Europe in 2010. By far the most popular are beta-carotene used for orange and yellow colours and curcumin, or turmeric (yellow). Both can be applied using natural processes.Curcumin can be labelled by name, depending on extraction method.

As an aside, the status of several colours remains under scrutiny by the European Commission (EC), which is determining whether they should be labelled as colouring foodstuffs or natural colours. Natural colours are classed as additives with E-numbers and need a lengthy approval process.

The relevant colours are: orange carrot; black carrot; elderberry; hibiscus; red cabbage; safflower; spirulina; turmeric/curcumin; paprika; pumpkin; beetroot; nettle extract and gardenia concentrates. LFR suggests the EC has been held up by its work on finalising a flavours list.

UK patents pending for colour development are a good indication of current trends and Rachel Wilson, LFR's principal technical advisor ingredients, says they fall broadly into three camps. They are: new natural sources of colours, with the main areas of investigation being marine or bacterial environments; colours for very specific applications, such as replacing nitrates; and enhancing colour stability.

Downsides to natural colours

And so we arrive at the downsides to natural colours. LFR says the biggest single focus for inquiries in this area is shelf-life and stability testing. This is because naturally-derived colours, and colours which can be labelled as natural foodstuffs, often blanch or cloud more quickly than their more artificial counterparts.

This is such a thorny issue that LFR has established a stability testing service for natural colours following a study led by its senior research scientist (food innovation) Annie Teoh in 2010.

Degradation can occur due to the effects of pH; light; temperature and oxidation reactions with other ingredients. Chlorophyll, for example, which is used to create an olive green colour, is one of the most vulnerable natural colours to all of these factors. Solutions are constantly being found to particular problems, but so much depends on storage and display conditions, product composition and processing techniques that many must be tailor-made to individual products.

That said, some breakthroughs offer general benefits. For example, LFR says vegetable-derived anthocyanins, which are used for red or blue shades, are more stable to light than fruit-based anthocyanins. Sweet potato and red cabbage anthocyanins offer better light stability than grape or berry anthocyanins.

Heat treatment can make many natural colours more prone to oxidation, making them break down quicker, says research and consultancy firm RSSL. Current solutions here range from upping the amount of colour used to replacing oxygen with nitrogen in drinks bottles to reduce exposure to oxidation.

Lionel Lesegretain, colour business manager at Naturex, adds: "Recent developments have resulted in a natural alternative to carmine which is derived from a vegetable extract and offers improved stability above current anthocyanin sources with the added benefit of brighter red shades at higher pH."

Move away from carmine

Some industry commentators claim there has been a move away from carmine, which is used to produce red and orange tints. This is partly because it is derived from the cochineal insect and so is unsuitable for certain diets.

"The main trend in the US and Europe has been to replace carmine,"​ says Udi Alroy, vice president, marketing and sales for Israel-based LycoRed. "It's not vegetarian, it's not kosher, it's not halal. We have started to see a lot of requests to replace it."

Another driver behind this has been supply and demand, a further challenge for those switching to natural colours and colouring foodstuffs: often supply can be much more fragile. "The bell pepper [source of paprika] is fluctuating an awful lot," says Willetts. "As a result, paprika colours have gone up in price."

Global demand for carmine as a dye for personal care products soared in the second half of 2010. And availability fell because South American farmers growing the cacti on which the insects live had switched to other crops in an earlier period of low prices. "Demand went through the roof and supply through the floor,"​ says Willetts. Consequently, prices spiked, forcing many to try to find less expensive alternatives. Carmine price hikes have subsided, but market volatility is still a worry, says Willetts. "There was a point where you would be lucky to be offered any material at all. We have seen prices in Europe reaching £1,000/kg."

Some colours players have turned to fruit extracts as an alternative. LycoRed draws on tomato-derived lutein, lycopene and beta-carotene to offer natural red, orange and yellow colours in powder or solution. These also offer antioxidant benefits, such as helping to protect against cancer and inflammation.

In addition, antioxidants can themselves be used to enhance stability, says LFR's Wilson, citing ascorbic acid and rosemary extract as good illustrations.

"Lycopene is the most stable form of colourant,"​ adds Alroy. "From 2.8 to 7 pH there's no issue."

Synthetic hues hard to recreate

Stability isn't the only issue for those switching to natural colours. Once past this, they have to contend with the fact that the exact shades of synthetically-derived colours are sometimes difficult to recreate.

"Often artificial colours have hues/shades that can't be matched with one natural pigment,"​ says Lesegretain. "Blends of two or three are needed to give a viable option as an alternative to artificial colours."

Willetts adds: "You can shape different greens derived from plant extracts by blending them with natural yellows."

Some tints create more problems than others, says RSSL innovation manager Abigail Birch. "There are not many things occurring naturally that are blue. When it comes to things like this it's about changing consumer perceptions of what you can make natural."

Willetts says: "White is the other one. Aside from titanium oxide, there is no true white. Some people are looking at calcium salts, but they don't disperse well and give a dirty white."

Natural colours don't just force processors to rethink their palettes.

They can even affect flavour. "Beetroot​ [which is used for red and pink] might introduce an earthy note that is unacceptable for the product," says Birch.

Processors can be hugely impeded by the tribulations inherent in switching to natural shades, she adds. "We have seen rejections where the difference [in colour] is too big to be acceptable. As a result, six to eight weeks can be added to project lead times."

Some companies have to work hard at the wording on labels as a result of the lack of natural solutions for every colour, says Willetts. "You can see label declarations like, 'made using natural colours' and 'containing natural colouring'​."

Analyse this: gaps exist in testing for natural colours

More analytical methods are urgently needed for determining the amount of certain colours in food and drink, according to Dr Mike Scotter, principal analytical chemist at The Food and Environment Research Agency (FERA).

Scotter presented his thesis to delegates at a natural colours symposium in London last month, after the Food Standards Agency commissioned FERA to review analytical methods for natural colours.

Under EU law, Scotter explained, the consumption of food additives must be monitored to ensure Acceptable Daily Intakes are not exceeded, especially for young children.

A big surprise was the limited scope of tests for caramel colours in food, despite their prevalence. New testing technologies should be applied to develop methods and procedures, said Scotter.

He found gaps in analytical tests for certain types of carotenoids, although some tests for animal feed could be extended to food for human consumption. Existing methods could also be used to test for several carotenoids simultaneously, plus other colours such as chlorophyll.

Anthocyanins posed problems

Analysis of anthocyanins also posed problems because of their chemical complexity and diversity, with few tests adapted for processed foodstuffs.

Some tests existed for chlorophylls and chlorophyllins, but their scope needed to be broadened to encompass all legally permitted foodstuffs. In addition, few tests were available for curcumin, cochineal and beet red, said Scotter. And while there were several tests for riboflavin, they didn't cover all food and drink categories.

"Conversely, there are very few methods available on the determination of inorganic colours such as titanium oxide in foods, and none for the direct determination of calcium carbonate and iron oxides in foods,"​ added Scotter. "Methods based on elemental analysis are likely to be the best approach for these colours because the amounts of the additives required to achieve the required colouring effect will be relatively high compared to natural levels. Such methods require significant development for application to foods and beverages."

Scotter found no references for methods to determine quantities of vegetable carbon, which is otherwise known as E153 or 'carbon black', and is used to make foods such as liquorice and some jams black.

Key contacts

Innova Market Insights 0031 26 319 0650

Leatherhead Food Research 01372 376 761

LycoRed 01622 713700

Naturex 01283 224221

RSSL 0118 986 8541

Univar 0845 602 6092

Related topics: Ingredients

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