Fruit fibres offer novel encapsulators for bioactives

By Stephen Daniells

- Last updated on GMT

Related tags Nutrition Food industry

The use of natural fruit fibres to encapsulate bioactive compounds
could offer a multipurpose functional food, and remove the need for
maltodextrin for spray-drying, Australian scientists have reported.

University of Sydney researchers Don Chiou and Tim Langrish, in collaboration with Tim Lang from Lang Technologies, told that the development has several important implications for the nutraceutical industry, including providing dose control, delayed release of bioactives, improved stability of the bioactive during processing, and offering synergistic benefits of the fibre and bioactive. To illustrate the potential of this new technology, Chiou and Langrish looked at the potential of milled fibres from citrus to encapsulate antioxidant bioactives from Hibiscus (Hibiscus sabdariffa L.​). The research will be published in the September issue of the Journal of Food Engineering​. "The combination of these fruit fibres and bioactives (Hibiscus sabdariffa L.) has created a novel nutraceutical product suitable for a variety of applications in functional food manufacturing,"​ wrote the researchers. "Through characterisation of the product, it appears that the material is appropriate in terms of its moisture content and encapsulation of the bioactive material,"​ they added. The research taps into an ever-growing trend for food manufacturers to use microencapsulation technologies as a way of achieving much-needed differentiation and enhancing product value. Tapping into key and emerging consumer trends with innovative techniques is becoming increasingly important for food manufacturers. Microcapsules are tiny particles that contain an active agent or core material surrounded by a shell or coating, and are now increasingly being used in food ingredients preparation. "We expect that this technique is applicable across a wide range of fibres not only from fruit, but also from cereals, pulses, oil seeds and sugar cane where the bioactive compounds are water soluble. We intend to develop this technology for fat-soluble compounds,"​ the researchers told this website. Indeed, the researchers confirmed that an announcement would be made soon about their involvement in berry fruits (Canada), citrus (USA) and sugar cane (Australia). To date, the research is an exclusive collaboration between the University of Sydney and Lang Technologies, a company with a background in technological research and strong ties to academia. The technology centres on mixing the fibres with the bioactive extract to form a slurry, which is then spray dried to form a powder, with a moisture content considered suitable for storage and consumption. Laser diffraction measurements of the citrus fibre-Hibiscus extract combination showed that particle sizes ranged from 16 to 23 micrometres. "If the storage conditions can be maintained under a relative humidity of 50 per cent, then the powder is unlikely to cake,"​ wrote Chiou and Langrish. They added that the potential of the fibres as encapsulators was confirmed by the detection of the bioactive inside the fibres. This demonstrated the potential of these fibres to replace maltodextrin-type carriers for the spray drying of sticky and sugar based bioactives, said the researchers - an important development for the food industry. "The properties of maltodextrins, in terms of undesired taste alteration and also being an unnatural additive, mean that a suitable alternative carrier for spray drying needs to be found,"​ explained the researchers. "This carrier needs to have appropriate encapsulation properties. It is possible that natural fibres may be able to fulfil this role, and this possibility has been investigated,"​ they added. Talking exclusively to this website, the researchers said that this could lead to the development of ingredients with several benefits. This includes dose control, "particularly where effective doses for bioactives are in the range 100-300 mg per meal compared with 5-15 grams per meal for fibre."​ The technique could also "assist the delivery of astringent, but highly beneficial, components of the diet benefits,"​ said the researchers. This would be achieved by by-passing of olfactory senses. The combination of the fibre and the bioactive could also produce synergistic benefits, said the researchers. "We can influence preferential transfer of healthy compounds through the intestine wall,"​ they said. "The combination of healthy bioactives, such as flavanoids, with citrus fibres is an example of providing these combined benefits."​ Work is confirmed to be continuing, with the researchers undertaking a comparative study into the effects of drying technique on bioactive efficacy, and the development of new products. Source: Journal of Food Engineering​ (Elsevier) Volume 82, Pages 84-91 "Development and characterisation of novel nutraceuticals with spray drying technology" ​Authors: D. Chiou, T.A.G. Langrish

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