The food industry is under pressure to develop healthy products with increasingly low energy density. This is why the food ingredient industry is constantly striving to bring new performance ingredients – additives that improve the texture of a product without deteriorating its nutritional value – to the market. The industry is especially excited about ingredients that make it possible to incorporate water and air into the structure of products. Carbohydrates that are not broken down in the digestive system or absorbed in the small intestine, but that have the potential of being fully or partially fermented in the colon, i.e. dietary fibres, are one example of compounds that show potential in this respect.
The food industry sees these indigestible carbohydrates as potential multifunctional components that could be used to create textures that appear light, but that still retain the health-promoting properties of dietary fibres. The health benefits of dietary fibres include lowering the risk of cardiovascular diseases, enhancing immune function, promoting gastrointestinal health, and helping to maintain a healthy weight .
Adding dietary fibres to food products in the form of additives often leaves the levels of the health-promoting component low, and, therefore, compromises the associated health benefits. If the goal is to harness these health benefits, the properties of the ingredient need to be modified to enable enough of the ingredient to be added to the product. The challenge here lies in keeping the health-promoting component active and stable, without sacrificing the texture of the product. This article gives examples that are based on technologies developed by VTT in both fields: dietary fibres as textural components, and as functional compounds in products that claim to have health benefits (see Figure 1).
Figure 1. VTT’s research and development relating to new multifunctional fibre ingredients.
Multifunctional carbohydrates as a source of textural sensations
The four key goals in developing new, lighter textures based on dietary fibres are to 1) give volume to the product, 2) keep the structure of the product stable, 3) create a pleasant and appealing mouthfeel without affecting the flavour of the product, and 4) not cause unpleasant side effects. The last point is extremely crucial, as some of the currently marketed carbohydrate-based additives, such as inulin, cause gastrointestinal problems for some consumers. These problems are due to the rapid fermentation of carbohydrates in the gastrointestinal system, and the resulting formation of gas. On the other hand, carbohydrates that are inert, i.e. that cannot be broken down by gut flora, do not deliver all the health benefits that are typical of dietary fibres.
Another dietary fibre that is already widely used in the food processing industry is polydextrose. However, polydextrose is a synthetic dietary fibre and has an E number (E1200) attached to it, which consumers tend to find off-putting. In addition to ensuring technological functionality, the search for new multifunctional products also needs to focus on delivering health benefits from natural ingredients without negative side effects, such as flatulence.
With this in mind, VTT is exploring the possibilities of using new, natural, e.g. wood-based, carbohydrates as multifunctional components in the food processing industry. The goal is to study the structural and stabilising properties of different kinds of modified fibre components, their ability to lower cholesterol, and how they react with gut flora. One example is xylan, a carbohydrate that can be isolated from birch trees and processed by biotechnological means, which has been proven to work exceptionally well in yoghurt products (milk-based gels). Xylan is, on the one hand, an excellent textural stabilising agent (see Figure 2), and, on the other, it breaks down slowly in the gastrointestinal system (as opposed to inulin), which makes it less likely to have unpleasant side effects.
Figure 2. Xylan extracted from birch trees (right) improves the textural properties of fermented milk gel (yoghurt): Researchers successfully used xylan in order to produce a more homogeneous and softer texture without liquid separation during storage.
In addition to birch-based xylan, VTT is also actively investigating the possibilities of using fibrillated cellulose to form and stabilise gels, foams and emulsions. Fibrillated cellulose has excellent water-holding properties, and gelatinises at extremely low (< 1%) concentrations. Fibrillated cellulose, and especially “native” cellulose, withstands variations in pH, temperature, shear forces, and ionic strength extremely well. VTT is currently exploring the potential of using fibrillated cellulose as a stabilising and thickening agent in cultured dairy products (e.g. yoghurt). (see Figure 3)
Figure 3. Solution of cellulose nanofibres (CNF) and milk. The microscope pictures in the bottom row clearly show how native CNF (a) dissolves in milk better than TEMPO-oxidised CNF (b).
In addition to their gelatinisation properties, fibrillated cellulose components have been found to stabilise emulsions, which could make them a potential natural, plant-based substitute for current surfactants (such as mono- and diglycerides of fatty acids, and lecithins) (see Figure 4). Fibrillated cellulose components are believed to stabilise oil-in-water emulsions either by attaching themselves to the oil droplets or by raising the viscosity of the continuous phase by forming a network around them (or both) [3, 4].
Shrewd modification and application of cellulose could make it a multifunctional ingredient for food products, and enable the production of completely new kinds of emulsions, as well as foams.
Figure 4. Fibrillated cellulose increases the stability of oil-in-water emulsions against shear forces (the picture was taken after centrifugation: Unmodified fibrillated cellulose on the left, and chemically modified and fibrillated cellulose on the right).
Soft drinks can bring cholesterol levels under control
Drinks are the most rapidly growing area of functional foods. The drinks manufacturing industry is constantly looking for new, consumer-relevant product benefits, one of the most important of which is high fibre content.
VTT has developed and patented an innovative technology, which enables increasing the solubility of dietary fibres – in this case the beta-glucans in oat or barley – by lowering the degree of polymerisation. Beta-glucans have scientifically proven health benefits: They lower blood cholesterol levels, have a low glycemic index (blood sugar level after a meal), and promote gastrointestinal health.
There are already several drinks that contain dietary fibres on the market, which are typically based on soluble fibre ingredients, such as inulin or polydextrose. However, as has been mentioned above, these components do not agree with all consumers. Modified soluble beta-glucans have the potential of providing a unique solution for incorporating a consumer-relevant amount of natural fibres in functional beverages, and justifying health claims in product labels.
The technique for producing soluble beta-glucans is based on two patented technologies developed by VTT. Soluble beta-glucans are produced from oat brans by means of either enzymatic or acid-catalysed hydrolysis (see Figure 5). During hydrolysis, the degree of polymerisation of beta-glucans is lowered to approximately one 16th of the original, which increases their stability in water-based solutions considerably. Three different forms of beta-glucans have been explored for use in drinks: powder, concentrate, and a ready-to-drink form. These options give the ingredient a wider range of applications.
Figure 5. The controlled break-down of beta-glutens enables their use in drinks. The process is based on the patents of Kaukovirta-Norja, et al, 2009, WO 2009/077659, and Lehtomäki and Myllymäki, 2009, WO 2009/109703 A1.
VTT has an active cross-scientific research team for new multifunctional ingredients development, which consists of Panu Lahtinen, Juhani Sibakov, Terhi Hakala, Natalia Rosa-Sibakov, Martina Lille, Anna-Marja Aura, Marie Gestranius, and Tekla Tammelin. It is already clear, based on the team’s findings so far, that wood-based carbohydrates have considerable potential as multifunctional ingredients in the manufacture of healthy food products. It also appears to be only a matter of time before beta-gluten drinks are available in shops.
Dr Emilia Nordlund heads VTT’s food solutions research team. The team’s goal is to generate well-being for people and the environment by means of innovative, healthy, and sustainable food solutions.
 Anderson JW, Baird P, Davis RH Jr, et al. “Health benefits of dietary fibre,” Nutrition Reviews, 2009;67: 188–205.
 Raninen K, Lappi J, Mykkänen H, and Poutanen K. (2011). “Dietary fibre type reflects physiological functionality: comparison of grain fibre, inulin, and polydextrose,” Nutrition Reviews, 2011;69: 9–21. doi: 10.1111/j.1753-4887.2010.00358.x
 Denkov ND, Ivanov IB, and Kralchevsky PA. Journal of Colloid and Interface Science, 1992, 150, 589–593.
 Horozov TS and Binks BP. Angewandte Chemie, 2006, 45, 773–776;** Abend S, Bonnke N, Gutschner U, and Lagaly L. Colloid & Polymer Science, 1998, 267, 730–737.
 Myllymäki O and Lehtomäki I.”Method of producing a bran product” (FI20085205).
 Kaukovirta-Norja A, Lehtinen P, Virkajärvi I, Suortti M, Myllymäki O, Helin J, and Olonen A. ”Method of processing beta-glucan” (FI20070993).
 Kaukovirta-Norja A, Myllymäki O, Aro H, Hietaniemi V, and Pihlava J-M. ”Method for fractionating oat, products thus obtained, and use thereof” (FI20075090).
 Gestranius M, Stenius P, Sjöblom J, and Tammeli T. ”Phase behaviour and stability of nanocellulose stabilised oil-in-water emulsions,” 18th ISWFPC Conference Proceedings, Vol 1, 9–11 September, Vienna, Austria, 2015, 7–10.