Super-Stable Colours That Pass The Test
Thursday, October 19th, 2017
Natural colours are the basic expectations by consumers now, but it is also critical that these maintain the expected visual appearances of products, regardless of application. Christiane Lippert, head of Marketing, Food, Lycored, discusses how they tested the stability of lycopene and betacarotene in beverages and what they found.
We’re in the middle of a sea change in attitudes to colours in food and beverages. It’s no longer enough for products to look good—customers now demand that the colours that make them appealing are achieved safely and naturally.
More than three in five consumers globally say they try to avoid artificial colours. In Asia-Pacific, the desire to avoid artificial ingredients is particularly strong. Eight in 10 consumers in the region—more than anywhere else in the world—say they are concerned about the long-term health impact of artificial ingredients.
Manufacturers who make the switch from artificial to natural reap the rewards. When 506 health-conscious consumers were asked, “Would you be willing to pay more for a product with natural flavourings and colours?” almost nine in 10said they would. On average they said they would pay up to 47 percent more.
However, going natural can also be technically challenging. Some non-artificial colours are sensitive to pH, UV light and extreme temperatures, and may not interact well with some recipe matrices, such as high fat systems.
We carry out frequent research into the stability of natural colour solutions. This paper outlines the results of recent stability tests in three categories: flavoured and coloured sparkling waters; UHT-treated, coloured, flavoured milks; and fruit preparations for layered yogurts.
In particular we wanted to test the effectiveness of colourants from lycopene and betacarotene, and to compare them against other natural options.
The Advantages Of Lycopene And Betacarotene
Lycopene is a bright red carotene and carotenoid pigment, found in tomatoes and carrots, as well as in other red fruits and vegetables. Betacarotene is a red-orange pigment that is found abundantly in plants and fruits. Both these pigments offer several advantages over other natural colourants:
- Provides authentic, vegan pink to red shades
- Highly stable under a wide range of pH, light and high-temperature conditions
- More vibrant with the addition of vitamin C (ascorbic acid)
- Stable in products containing vitamin C (ascorbic acid)
- Shade variations and formulations suitable for high fat systems
- Greater versatility than other naturally sourced red options (beet is sensitive to heat, anthocyanins are sensitive to pH, and carmine is not consumer-friendly)
- Well known by consumers
- Offers a spectrum of natural, vegan yellow to orange shades
- Shade variations and formulations for a wide range of food and beverage applications
- Highly stable under a wide range of pH, light and high-temperature conditions
- Stability is amplified with the addition of vitamin C (ascorbic acid)
Both are certified kosher and halal, vegetarian-friendly, non-GMO, heat, light, and pH stable, safe and easy to use, from our own strictly controlled vertically integrated source.
Testing The Stability Of Lycopene And Betacarotene In Beverages
We first set out to test the stability of colourants from lycopene and betacarotene in flavoured and coloured sparkling waters—one of the beverage categories for which they are ideal.
Researchers assessed the stability of three natural colours derived from lycopene, and four from betacarotene.
Sparkling water was added to strawberry-flavoured syrup and filled to 250 ml in PET bottles, with 200 ppm of ascorbic acid added to prevent colour fade over a 12-month shelf-life. Each sample was checked for ringing, sediment and fade at regular intervals.
Six of the seven lycopene and betacarotene colours delivered good stability over 12 months (the other delivered good stability up to nine months). There was no ringing at all over 12 months in four of the samples.
There was no sediment in five of the seven samples. In summary, the colours from lycopene and betacarotene delivered excellent performance in sparkling flavoured waters, demonstrating resistance to fading, ringing and lack of sedimentation.
Super-Stability In UHT Treatment Processes
Increasingly, there is evidence that natural colours perform just as well as—or better than—artificial alternatives.
For example, we tested the performance of natural reds from lycopene in flavoured UHT milk drinks. Three strawberry milk drinks were prepared, two with natural colours from lycopene and one with an artificial colourant. The drinks were subjected to four different UHT process technologies: steam injection, plate, tubular, and infusion.
In many of these processes, such as steam injection, the recipe is heated above 145 deg C and held in direct steam for over five seconds, which is very rigorous. As with all UHT processes, they were also subjected to a upstream or downstream homogenisation treatment.
Immediately after UHT and homogenisation treatment, the researchers measured the samples for any changes in colour using HunterLab’s colour measurement software and the DeltaE method of calculation. Under this system, a DeltaE score of two or below indicates that there has been no change that is visible to the naked eye.
The two natural colourants both performed exceptionally, with the samples that had been subjected to the harshest direct injection treatment achieving DeltaE scores of 0.52 and 0.67 respectively. The artificial colourant by contrast, scored 10.55 and experienced a dramatic variation in colour during the direct injection process.
We also evaluated the performance of the colours in accelerated shelf-life tests, which simulated the harshest possible conditions during transportation and storage and whilst on sale (under lights and chiller conditions) in storage.
In a test to determine the colour stability of the UHT strawberry drinks in ambient conditions, the natural colours also performed well. After six months at ambient temperatures of between 25 and 40 deg C, there was no visible difference in their colours. However, there was a marked difference in the colour of the artificial sample. This demonstrates that drinks coloured with natural reds from lycopene can retain their colour over a long ambient shelf-life, and perform better than artificial options.
Avoiding Bleed In Fruit Preparations For Yogurts
A range of natural colour sources are commonly used in fruit preparations in yogurts. These include lycopene and other carotenoids, foodstuff colourings such as carrot concentrate, paprika and carmine. We set out to explore how well different natural colours perform in this category. In Phase 1 we monitored and assessed the comparative appearance of yogurts containing fruit preparations over a shelf-life of 31 days.
Twenty-four unique samples were tested. Each sample of 100 g full fat Greek yogurt contained 40 g of preparation from four common fruit varieties—lemon, apricot, peach and strawberry. For each fruit variety, at least one sample contained an appropriate natural colourant from lycopene or betacarotene, and at least one contained an alternative natural colourant. For some of the samples we also assessed the performance of fruit preparations with no colours.
The samples were all tested in two different stability environments. In one, temperature was controlled at 4 deg C for 30 days. In the second, temperature was controlled at 4 deg C for 30 days under light of 2,200 Lux.
In the yogurt containing lemon preparation, there was significant fading and migration in the sample coloured with paprika compared with that coloured with betacarotene.
In the strawberry samples, there was severe migration from the carmine-based colourant, compared with those coloured with colourants from lycopene. This was the case even in the samples containing pectin. There was also significant fading and distortion from the sample containing fruit preparation with no colour.
In the yogurt containing apricot preparation, the betacarotene colourant delivered high vibrancy and lack of fading compared with the carrot concentrate. This was the case even in light cabinet conditions (double the typical grocery chiller cabinet temperature of circa 750 to 1000 Lux).
In the peach yogurt, there was significant fading and migration in both the sample with no colourant and the sample coloured with carrot concentrate. By contrast, the colourant from betacarotene delivered far higher stability.
The trials from Phase 1 demonstrate that:
- Fruit bases or preparations in yogurts need added colour to retain vibrancy and fresh appeal
- Natural colours from lycopene and betacarotene can be colour-fast even under light conditions more extreme than retail lighting conditions
- Natural colours from lycopene and betacarotene offer authentic true to fruit and vibrant fruit shades from lemon yellow to strawberry red
- Migration is a real issue for carmine based colouring in strawberry, even when paired with pectin
Phase 2—Industrial Scale Up
In Phase 2 we assessed the stability of four colourants from lycopene and betacarotene under the stronger and longer heat process of scaled industrial production. We wanted to assess how stable they were when heated to 75 deg C, 85 deg C and 95 deg C. In each of the samples, the colours remained stable at 95 deg C when held at that temperature for over 30 minutes.
The tests showed that natural betacarotene and lycopene colourants can both be process-stable, even when subjected to high heat levels and holding temperatures over 30 minutes.
Betacarotene can be tailored to achieve multiple true to fruit shades for lemon, pineapple, apricot, peach, and mango. Lycopene delivers red shades for authentic strawberry and raspberry and many other red berry and fruits varieties that maintain their vivid hue and do not fade to purple when blended into yogurt. Both are process stable and stable to UV light in a chiller cabinet.
Manufacturers now have greater opportunities than ever to colour products naturally without compromising on stability. In fact, rather than creating limitations, these super-stable colours offer new ways to position products as more natural, authentic and fresh, with longer shelf-life. They can also potentially reduce the operational costs involved in packaging, transport and storage of final product.
Every day we are learning more about the possibilities offered by natural colourants and showing that they demonstrate stability in a growing number of applications. Frequently we discover that they outperform not just other natural alternatives, but also artificial colourants.
There is a long-standing perception that natural colours are harder to work with than artificial alternatives. We are working towards a day when that is a thing of the past.
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