Page 19 - University of Pretoria Research Review 2017
P. 19

         Foreword
Introductory Messages
Christopher Cullis, Case Western Reserve University, US; Professor Karl Kunert, Extraordinary Professor
in Plant and Soil Sciences at UP; and Professor Percy Chimwamurombe, Namibia University of Science and Technology.
Modern DNA technologies make it possible to obtain a detailed understanding of genetic diversity and local adaptation of T. esculentum and related species such as T. fassoglense. This information will be of value in future plant breeding experiments on this species,
as such experiments require a clear understanding
of species limits and population differences. A living collection of these plants is being established at the University of Pretoria’s experimental farm situated on the Hillcrest Campus.
Waste, not food waste
John Taylor, Riëtte de Kock and Janet Taylor, Institute for Food, Nutrition and Well-being
Brewers spent grain (or BSG) is one of the biggest waste by-products in the brewing industry. A team of food scientists at UP is investigating ways in which this waste can be put to good use.
Professors John Taylor and Riëtte de Kock, and Dr Janet Taylor have been leading a group of postgraduate students to find ways to convert BSG into nutritious food, as well as environmentally-friendly packaging materials.
They are currently working on using BSG as a partial substitute
for wheat in the production of a higher-fibre and high-protein bread. The team has shown that simple physicochemical modifications of
BSG prior to its use as a functional food ingredient can potentially give quality, high-fibre wheat-BSG composite bread. The innovation also has a financial benefit that could help reduce the expense incurred when using wheat flour in bread, as wheat is mostly imported.
The researchers have also experimented with substituting some of the wheat in the production of a convenient snack biscuit. They have found that substituting 50% of the wheat flour with BSG results in nutritionally superior biscuits with a higher protein and fibre content than if only wheat were to be used. What is interesting is that the 50:50 ratio of wheat and BSG seems to be sensorially acceptable compared, for example, to a standard ginger biscuit. This is a good sign as to whether the product will be accepted as a good and nutritious snack.
An additional aspect of the project is the production of a rigid bioplastic food packaging material, by using a combination of BSG with another waste product from the cornstarch wet milling industry, called gluten 60. This cornstarch by-product contains almost 60% protein (mainly zein, the storage protein of maize kernels) and when
Preliminary results suggest that species limits
based on plant morphology are not supported by
the DNA data, indicating some intriguing historical evolutionary processes that are at play. In particular,
T. esculentum (the typical Marama bean from the Kalahari) is genetically indistinguishable from samples of T. fassoglense, which occurs in the savannah regions. While these species differ in seed shape, it is possible that such differences are recently evolved and that this is simply one variable species complex, and that gene flow between populations is still ongoing. Alternatively, the Kalahari species is of such recent origin that there has been insufficient evolutionary time for it to acquire its own unique genotype. The fact that these species are very similar means that this variable gene pool can be exploited in future plant breeding programmes.
Postgraduate student, Jillian Oosthuizen, prepares a tray of spent grain biscuits for baking.
combined with BSG, produces a material that resembles papier mâché. The team hopes that the product will add value to the takeaway foods industry in South Africa and further afield, as it is food-compatible
and biodegradable.
DEVELOPMENT AND CHANGE
Food Security
PEOPLE AND CONTEXTS
HEALTH AND WELL-BEING
PLANET AND SUSTAINABILITY
Awards
Lead Researchers
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