The incredible bulk: Fibre in focus

Mention fibre in food manufacturing and everyone wants to talk about its dietary role: either supporting 'friendly' gut bacteria or creating feelings of satiety to encourage weight loss. Prebiotics is certainly where the focus of new product development seems to be, according to Frost & Sullivan.

"Prebiotics for digestive health showed overall demand [volume] growth of close to 12% in 2009," said Sneha Pasricha, research analyst, Chemicals, Materials and Foods at Frost & Sullivan. "The growth is expected to range between 4.5% and 18.5% this year, depending upon the type of prebiotic fibre and its product life cycle stage."

Overall, fructans (inulin and oligosaccharides) hold the maximum volume share of prebiotic fibres in the EU. Others collectively account for less than 20% of the market, says Pasricha.

Yet developments continue in the technical roles of fibres, whether it be improving mouthfeel, increasing shelf-life, enhancing texture or offsetting the undesirable effects of other ingredients.

Fibres such as polysaccharides, including pectins, xanthan gum and guar gum are often used to bind water, making it less free-flowing in, say, yogurts or meats, to make them more succulent and improve texture.

"A new application area seems to be in meat, more specifically in processed meat products such as sausages," says Dr Diederich Meyer, scientific and regulatory affairs boss at Sensus, one of the top three EU fibre firms. Sugar beet fibre, supplied extensively by firms such as Danisco, for example, is used in this regard.

"The water-binding capacity of fibres might improve texture and at the same time improve the health image of such products," adds Meyer.

Beet fibre can also be used in fat reduction, as Matthias Hansson, key account manager for Nordic Sugar's Fibrex product, says. "Lately we have been focusing on the technical uses of Fibrex within coating systems and fat reduction where recent studies have shown that Fibrex reduced the fat uptake of coated and fried chicken meat from roughly 60% to 30%. Previously we have also seen similar benefits in batter doughnuts."

Jon Arzberger, product manager for health food at Azelis Food and Health, says: "There's growth in fibres for moisture retention in bakery and meat applications. Citrus fibres work well in bakery for fruit pie fillings, so manufacturers don't end up with the pastry collapsing halfway through the baking process. They lock in moisture, so pastry doesn't lose its crispness."

Fibres can be a 'clean label' alternative to phosphates, making poultry meat juicier, he says. Carageenans, fibres derived from seaweeds, are one example, although these are still viewed with suspicion after media stories now debunked linked them with cancer.

Because of their use to control moisture an essential issue in product degradation fibres can also be used to extend the life of certain foods. "It depends on the packaging, but you can get three or four more days of shelf-life," says Arzberger. "You can also increase freeze storage capability, because you can stop the water forming large ice crystals."

While often addressed separately, it's important to remember that starches are also forms of fibre. There's a lot of activity currently in the use of resistant starches as texturisers, says Meyer, with Roquette and National Starch both major forces.

Ideally, processors want to have their cake (or bread/dairy product/beverage) and eat it, constantly chasing fibres that can perform technical and health-promoting functions.

It's here that inulin and oligofructose outperform many alternatives, says Meyer. "The problem with using sugar beet or rice fibre is that if you add a lot, you will affect product texture, so it won't easily be palatable." By contrast, inulin and oligofructose can be used for technical and health reasons, which helps explain their combined double digit growth in sales volumes, he says. Sensus is known to be ramping up its production of inulin and fructo-oligosaccharides.

Consequently, they are used extensively to convey health benefits because they can be present in products in quantities demanded by EU law to justify nutrition claims. "In the EU, for making a source of fibre claim at least 3% of fibre is needed, which may be too high for certain applications," says Meyer. "This is all the more so for high-in-fibre claims, which require at least 6% of dietary fibre."

Meanwhile, on the technical level, inulin is used increasingly in dairy products from spreads to ice cream to convey a creamier or more buttery mouthfeel, he says. Inulin and oligofructose are also used as sweeteners to replace sugar, without the unpleasant flavour notes some claim accompany high-intensity sweeteners. They can also enhance fruit flavours, he says.

However, in general, fibres are like musical instruments. While some may be versatile enough to be used to make a variety of impacts on those who sample them, the best results are often achieved by blending them together in a symphony. "Intense sweeteners have a lingering taste. By combining them with inulin or oligofructose you get a taste profile that's closer to traditional sugar," says Tim van der Schraelen, marketing and communications manager for Beneo, which makes both from chicory.

Meyer says: "Fibre preparations are often mixtures of insoluble and soluble fibres, such as various types of bran, beet or apple fibre, with profound effects on food flavour and texture.

"Inulin addition to bread dough will affect processability, but addition of another fibre (a cellulose derivative) and a slight change in processing conditions will overcome this. Oligofructose can be broken down by yeast enzymes during leavening of bread, which can be prevented by using long-chain inulin."

Even single fibre compounds require fine-tuning, he says. "With proper processing we are able to manufacture different chain-length inulin with different technical functionalities. Short- chain oligofructose is highly soluble, whereas long-chain inulin is less soluble but offers gelling properties and an enhanced mouthfeel."

Overall product conditions are a factor in determining which type of fibre to use. "A clear beverage requires a soluble fibre that remains in solution over the whole shelf-life (oligofructose works very well here)," says Meyer. Fibre stability has to be taken into account, for example, below pH 3.5 inulin breaks down at room temperature, making it inappropriate on its own in ambient, acidic beverages.

Van der Schraelen adds: "You couldn't use oligofructose in [leavened] bread, because it's consumed as food by yeast." Consumer needs also dictate the type of fibre used, he says. The growing gluten-free market, for example, is leading to increased demand for rice fibre to replace wheat fibre in bakery products.

While certain fibres may have health-promoting as well as technical benefits, though, manufacturers can't leap too far ahead of consumer acceptance. Ultimately, it's easier for shoppers to relate to the health-giving benefits of fibres in, say, breakfast cereals or bread than it is for them to embrace a 'high-fibre' sausage.

But that's no reason to give up on the idea. Sufficient work on the health message could mean other categories less well known for high-fibre claims could one day boast them, says Meyer. "This requires both an effort from government, health care authorities and from the food industry to develop suitable high-fibre products."

Fruit beverages in particular offer opportunities that manufacturers could be making more use of, says Meyer. "Fruit is associated with fibre, so you could make something there. It's not popular in Europe to add new fibres to smoothies, maybe because of their effect on texture and taste, but in Asia it's more common." Arzberger says: "Smoothies are good examples. They have a reasonable fibre content and it doesn't take a lot to boost them up to be the source of a nutrition claim. The time is probably around now for dairy and beverage products. The interest we're getting would seem to indicate manufacturers are looking at this."

In addition, more could be made of soluble and insoluble fibre combinations in Europe. Van der Schraelen cites Kellogg's Dual breakfast cereal bran, which boasts insoluble wheat fibre to clean the gut and soluble, chicory-derived inulin for beneficial gut bacteria.