Process optimisation fort the production of high energy density fermented or acidified and extruded uji

The need to provide ready-to-eat and yet nutritious foods from local raw materials to economically disadvantaged populations across sub-Saharan Africa remains a major challenge. In light of this challenge, this dissertation considers extrusion technology as a means of improving the quality of uji (a thin fermented porridge mainly consumed by the poor in eastern Africa). Since the raw materials (maize, millets, sorghum and cassava) and methods of preparation of thin fermented porridges in sub-Saharan Africa are broadly similar, it is reasonable to expect that these results can be extrapolated to other thin porridges from the region. This dissertation will therefore be of special interest to “application-oriented” food engineers; but also has information of interest to nutritionists and food scientists. The dissertation begins with a general discussion of the results backed–up by extensive bibliographic references. This enables the reader to have a salient overview of the critical aspects of extrusion technology with special reference to thin fermented porridges. Reference is also made to the microbiological characteristics of thin fermented porridges and the associated flavour development and nutritional and health challenges. Subsequent to this section are five original articles, which have been reproduced exactly as they appear in the journals. Each article gives specific details on the objectives and methodologies used and a thorough discussion of the results.