DSTO scientists are working with their US Army counterparts to develop an energy bar containing gluten-free flour derived from waste green bananas that would minimise the effect of diarrheal disease on troops in the field.
The ultimate intention is to develop the bar to the stage where it can be picked up by industry and turned into a product that can then be cost-effectively acquired by Defence.
The green banana flour contains about 35 per cent resistant starch which recent research has shown to be beneficial to gut health and the immune system.
DSTO Research This attribute emerged, according to Dr Simon Oldfield, head of DSTO’s Land Division, from the discovery that some African tribesmen had a very low incidence of bowel and colon cancer. This was subsequently credited to their consumption of corn maize, which develops yeast resistant starch after cooking and cooling.
This research has been followed up by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), which last year joined DSTO and the University of Tasmania in forming the collaborative Centre for Food Innovation (CFI).
Prior to taking up leadership of the CFI, Professor Roger Stanley, then with the University of Queensland, had worked with Roger Watkins of the Mt Uncle Plantation on the Atherton Tablelands west of Cairns to successfully develop the green banana flour.
However, as noted by Dr Oldfield, “it’s one thing to realise that banana pulp is a source of yeast resistant flour; it’s another thing to turn it into a food bar with a stable shelf life.”
The so-called Banana Bar project was boosted when Paul Capela, a research scientist at the DSTO Defence Nutrition Research Centre at Scottsdale in Tasmania, was awarded a Defence Science Fellowship and spent last year at the US Army’s Natick Soldier Systems Centre in Massachusetts.
Although his main project was to develop a gut fermentation model which could be used to predict health outcomes, by utilising Natick facilities and expertise he was also able to incorporate Mt Uncle banana starch into a First Strike energy bar.
Energy bars These bars are included in the US Army’s First Strike ration pack, a compact, eat-on-the-move ration designed for use during initial periods of intense, highly mobile combat operations. The 2.3 ounce First Strike bars included in the ration packs provide 272 calories and come in chocolate, apple-cinnamon, raspberry, cran-raspberry and mocha flavours. The mocha bars are fortified with 200mg of caffeine.
While the range of flavours on offer may at first glance appear inconsequential, palatability is a vital issue. If the bars are not attractive to the taste (and to the eye), they won’t be eaten.
“First Strike rations provide nutrition to soldiers while they’re on the move. What we’re exploring is adding probiotics (friendly bacteria) to that energy bar,” said Dr Oldfield.
“It gets to the heart of what we’re doing in Scottsdale. We’re interested in high value foods where components can be added not just to provide nutritional value but also enhanced performance, and this is a good example.”
The objective at Natick was to incorporate the maximum amount of banana flour in a First Strike bar without significantly affecting the bar’s textural and sensory properties.
Formulations containing 10 per cent and 20 per cent banana flour were produced and evaluated, with the 20 per cent mix found to have a superior taste and texture.
Testing The prototype bars returned to Scottsdale with Paul Capela in January and are now undergoing a one year accelerated storage trial. The bars are being stored at 1, 20 and 30deg C 40, 70 and 100F and will be analysed at intervals during storage for appearance, texture, palatability, and the residual level of resistant starch.
A long shelf life - at least two years, according to Dr Oldfield - is essential for military rations that may be prepared well ahead of consumption. The US First Strike ration packs, including the First Strike bars, are certified for a two year life in temperatures of up to 80F.
Dr Oldfield said the bars will subsequently be subjected to a sensory evaluation panel for appearance and palatability and must receive an overall score of five or higher on the widely-used nine-point hedontic scale to be considered acceptable.
This evaluation will presumably take place after additional work to attune the bars to Australian rather than US tastes.
After their release to US forces, First Strike bars became available in US supermarkets and there’s no reason this could not eventually be replicated with Banana Bars in Australia given their anticipated value-added qualities, Dr Oldfield acknowledged.
In another research development, DSTO’s relationship with the Natick centre has alerted it to Microwave Assisted Thermal Sterilisation (MATS), a new food processing technology on the cusp of commercialisation.
This technology was developed over 10 years for the US military by a research consortium headed by Washington State University (WSU) to produce high quality shelf-stable foods not requiring refrigeration or frozen storage, for military ready-to-eat meals.
MATS uses microwaves at a longer wavelength than those in domestic microwave ovens to rapidly heat, and hence sterilise, food sealed in plastic packaging. This is followed by fast cooling to preserve appearance, taste and texture, and to retain nutrition similar to that of freshly-cooked food.
Two prototype MATS machines have been installed in the United States for military food product development, and Dr Oldfield has confirmed DSTO’s interest, as part of CFI, in the possibility of utilising DSTO-Scottsdale’s researchers and newly-redeveloped infrastructure to host a MATS capability.
