Capture the castle

A decade ago bakers may have known that sorbic acid had potent anti-fungal properties but they also knew that it couldn't be used in bread because it kills yeast. So any idea of using it was simply a non-starter. Then Bristol-based Tastetech came up with a way of encapsulating sorbic acid that isolates it from the yeast until the bread is baked. And preserving bread using sorbic acid became a viable option overnight. This is a typical encapsulation story, where the arrival of new materials can sometimes solve problems that manufacturers didn't even realise they had.

"The key to the future is in identifying the need," says technical manager Gary Gray. "Sorbic acid is a good example. Once the bakers realised they could use the encapsulated form it created demand."

In fact, the novelty of encapsulated ingredients has sometimes been an obstacle, since manufacturers can find it hard to assess the possible advantages against the added cost of encapsulation. "One thing we've struggled with in the past is to get customers to understand they're dealing with a new ingredient," says Gray. "If you can't use an ingredient in its natural form then you can't compare the cost. They're two different ingredients."

So there have to be good reasons to opt for encapsulation, and manufacturers are increasingly finding them. It might be to do with protecting an ingredient from deterioration during processing or storage. It might also be to do with delaying the reaction of one ingredient with another or with controlling the release of the active ingredient, perhaps to prolong the flavour for the consumer for instance.

Tastetech specialises in encapsulation for the bakery and confectionery markets. One of its most recent developments is an encapsulated version of the sweetener sucralose, which gives gum manufacturers another tool for longer-lasting sweetness. "Whenever a new product comes out we think about whether we can achieve an advantage by encapsulation. The key is to keep a close eye on the market and identify the need," says Gray.

One of the strongest market drivers is the growth in functional foods and the growing popularity of ingredients that are fashionable but hard to formulate. Omega-3 oils are a great example. With a deluge of studies indicating that omega-3 can guard against brain, eye and heart problems, manufacturers are keen to include it in everything from infant formula and yogurts to cereal bars and soft drinks.

"One of the challenges of omega-3 is that it's very unstable to light, heat and air. And if it oxidises it can produce an off smell or off taste," says Cassie France-Kelly, spokeswoman for Martek Biosciences.

Martek supplies omega-3 DHA encapsulated in various formats, but newly acquired processes are constantly expanding the possible applications for its oils. The most recent addition is a technology acquired from General Mills, which France-Kelly believes will enable the firm to reach new markets by extending the shelf-life of DHA-enriched products beyond a year and even beyond the 18-month barrier. Cereals and confectionery are key targets.

LIFE ON THE SHELF​

Shelf-life has been an even bigger issue in Europe since regulations came into force in 2007 to harmonise fortification standards across Member States. Where some firms had routinely overdosed products with vitamins to ensure they remained at declared levels throughout their shelf-life, the new regulation (1925/2006/EC) set upper limits for inclusion. Encapsulation can help preserve vitamin levels throughout shelf-life. "Such regulations can have a profound effect on the drive for encapsulation," says Gray.

This problem-solving approach means that many new developments in encapsulation are aimed at niche applications. For example, in 2008 both Martek and Dutch encapsulation specialist FrieslandCampina Kievit independently launched their own protein-free omega-3 encapsulation technology to serve the hypoallergenic market.

In the case of FrieslandCampina Kievit, the new technology, called Vana-Sana DHA 7 IF protein-free, includes capsulates of other nutritionally important fatty acids such as omega-6. Rather than traditional, milk protein-based encapsulation, the firm has developed the product using modified starch, which is non-allergenic. The firm won Frost & Sullivan's 2009 Global Infant Nutrition Technology Award for its role in hypoallergenic infant formula.

Drinks of the more grown-up variety are also a big target market for encapsulation, largely thanks to the trend towards 'nutraceuticals' in developed markets. "In Europe there has been a tremendous increase in bottled waters and functional beverages, rather than carbonated drinks," says Claudia Fiannach, business development manager for beverages and spray dried flavours at National Starch. Functional beverages are expected to grow with a compound annual growth rate of more than 5% between 2006 and 2010, while carbonated drinks are falling back to 1.3% over the same period. "It's starting from a lower volume base than carbonated drinks but it's where all the new launches are coming from."

The dominant technology for dry ingredient encapsulation is spray drying, although more specialised techniques such as fluidised bed coating are growing with the increasing demand for specific release characteristics. For example, manufacturers want to protect probiotics until they have passed through the stomach and into the gut. In liquids, emulsification remains the dominant technology.

Gum arabic is the most commonly used emulsifier, but has limitations in terms of stability, its ability to be used with natural colours, temperature resistance and consistency between batches. According to Fiannach, modified starch can overcome all these functional limitations, but has been held back until now because it is chemically modified and cannot be labelled as natural. For this reason, National Starch has launched its Q-Naturale range, which is derived from the quillaia tree. It offers the same performance benefits as modified starch, plus a clean label. "Q-Naturale also offers big savings in cost and a much faster emulsification process, so manufacturers can double the quantities of functional beverages they produce," says Fiannach.

Clarity: the holy grail of beverages​

Nevertheless, the holy grail of beverages is visual clarity. And while firms such as National Starch say their solutions offer "nearly-clear" low-turbidity options, for a truly clear solution firms must look beyond the micron size range to encapsulation on a scale of around 50 nanometres or smaller.

German firm Aquanova has developed a technology based on micelles - self-organising groups of surfactant molecules - to deliver active ingredients in the 30nm range. Its NovaSol solubilisate technology, which was commercialised in 2005/2006, takes oil- or water-soluble actives and renders them totally soluble in oil or water.

As well as beverages and cosmetics, the company has been developing some other unusual applications, such as disinfection systems based on food-grade preservatives such as sorbic acid and benzoic acid. These enable disinfection of machinery surfaces without introducing chemicals that must subsequently be rinsed off. "Unlike the conventional materials, the liquid solubilisates will not crystallise on machinery surfaces," says Frank Behnam head of corporate development at Aquanova.

Not only does the NovaSol technology render a range of insoluble actives totally soluble, but the tiny size of the micelles used by Aquanova means that active ingredients are more bioavailable, whether they're in a food or in a cosmetic cream. However, nanotechnology in general has raised safety concerns in some quarters, and Aquanova is keen to distance its products from the controversy.

Earlier this year, the European Food Safety Authority struck a cautious note when it advised that the safety of engineered nanomaterials (ENMs) should be examined on a case-by-case basis. However, Aquanova argues that its micelle-based technology is not 'engineered' in the conventional sense and should be regarded in the same light as naturally occurring nanoscale micelles, such as those in eggs and milk.

In April, the company brought together a panel of external scientific experts to review the available evidence. The panel considered evidence from Germany's Federal Office for Risk Assessment and the Association for Food Regulation, as well as from the American Chemistry Council and the State Laboratory of Hesse. The expert panel concluded that micelle-based delivery systems have been around for decades, and that 'Colloidal systems such as liposomes and micelles can and should therefore not be regarded nor understood as, and therefore not confused with ENMs from a scientific or regulatory viewpoint.'

"It's important for industry to understand that there's a big difference between ENMs and the sort of colloidal systems that we're using," concludes Behnam. FIHN