URBAN ORIENTEERING NUTRITION
CSIRO research leading to healthier foods In the not too distant future, a bowl of cereal, muesli bar, sandwich or steaming bowl of pasta will not only satiate the appetite but have highly targeted nutritional roles.
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SIRO’s Food Futures National Research Flagship is developing new grain varieties and tailoring fibre content to optimise health benefits to consumers. Cereal grains are major sources of dietary fibre, an important contributor to human health. Dietary fibre fractions, such as non-starch polysaccharides (NSP), have the potential to lower cholesterol and the glycaemic response of foods as well as to promote regularity and improve bowel health. New grain varieties with improved health benefits also have the potential to be easier to process, thus saving on energy.
Benefits of fibre and NSP FIBRE is important because of its contribution to human health, including promotion of regularity, improved bowel health and, in the long term, protection against diverticular disease. Total dietary fibre consumption has been associated with lower risk of colorectal cancer. Fibre components can also lower plasma cholesterol and lower the glycaemic response of foods. Dietary fibre is that fraction of the edible part of plants or their extracts that is resistant to digestion and absorption in the small intestine, usually with complete or partial fermentation in the large intestine. The main contributors in typical diets are NSP (e.g. pectin in jam), resistant starch (e.g. high amylose maize) and oligosaccharides (e.g. inulin derivatives found in artichokes). Dietary fibre also includes lignins such as those found in wheat bran. The benefits of increased consumption of cereal NSP include enhanced laxation and the associated lowered risk of diverticular disease, and a possible reduction in the risk of coronary heart disease, diabetes, certain cancers, especially of the large bowel, and obesity. Human trials have shown that the soluble NSP found in particular grains, such as oats and barley, lower plasma cholesterol. Most of these issues will be of interest and concern to many older orienteers. Nearly all starch is consumed as cooked foods and is broken down into glucose in the small intestine, where it is absorbed into the body. However, resistant starch – the fraction that escapes digestion in the small intestine and passes into the colon, where it is broken down by resident bacteria – has important health attributes. Amylose, one component of starch, has been targeted because of its established health benefits. It is more resistant to digestion so it releases glucose more slowly, leading to a low glycaemic response. Research suggests that it can promote bowel health, reduce colorectal cancer risk and improve the control of blood glucose. Controlling blood glucose is important in managing Type 2 diabetes and may also help lower the risk of obesity.
Reducing food waste CSIRO is also working on ways to reuse the fruit and vegetable materials which are currently wasted during food processing. The beneficial fibres and bioactive components from these waste
streams can be added back into processed food products to replace currently added gums and stabilisers. Food processors waste between 20% and 40% of the vegetable material they process. Such items as stalks, skins, cores, outer leaves, etc, are all sent to waste. It is known that one food manufacturer discards 8,500 tonnes of apple, pear, peach and tomato components each year. Many processed foods have textures which are controlled by added gums and stabilisers such as guar or xanthan. By working out how these additives create texture and mouth feel, CSIRO researchers hope to develop ways to replace them with natural additives developed from the current fruit and vegetable waste stream. Components such as broccoli stems, apple cores and peels, oranges and lemons waste, and grape seeds and skins from wine making, are being targeted for reuse. Researchers are finding ways of reducing the unhealthy components of processed foods and of adding back many phytonutrients and antioxidants which consumers are missing in their regular diets. As well, natural colours and flavours may be extracted from these fruit and vegetable wastes. Researchers have already developed a colour palette made from 100% natural colourings.
The gluten problem Gluten is a protein found in wheat, rye, barley and oats. Eating gluten triggers an auto immune reaction in people affected by coeliac disease, resulting in intestinal inflammation and damage. One in 100 Australians have coeliac disease (although four out of five are as yet undiagnosed) and the only management option is life-long avoidance of products containing gluten.
Gluten free beer Sorghum, millet or corn based gluten free beers are commercially available. However these products lack the authentic taste of barleybased beer. By Australian law, a gluten free product must contain no detectable gluten. This is 5 parts per million or below, with current testing methods. CSIRO scientists are now working to produce barley varieties with gluten levels below the acceptable limit for coeliacs. Barley is genetically simpler than wheat, so achieving a gluten free barley variety is faster. This is an important proof-of-principle step on the way towards producing a range of gluten free cereals. In barley, the class of gluten-like proteins is called hordeins, and these are toxic to coeliacs. Scientists are working to remove these hordeins from barley. They started by combining two non-genetically modified barley mutations bred in 1975 by the Carlsberg Laboratories in Denmark. These mutations make the plants very low in hordein, providing a perfect starting point for the project. These lines have been crossed to reduce the hordein in the grain by over 90 per cent. Work is proceeding to further reduce the hordein level in barley. The initial taste tests on beers made from barley with 90 per cent reduction in hordeins are promising. The gluten free characteristics will be bred into current malting varieties, suited for growth in Australia, which will reduce the price of the final product to consumers. If all tests and research are successful, barley gluten free beer may be available on the Australian market by 2014. www.csiro.au/ff JUNE 2009 THE AUSTRALIAN ORIENTEER 29
