Abstract
For decades, mycotoxin contamination has been a source of food safety concerns in the world, sub-Saharan Africa (SSA) inclusive. To overcome this challenge, food processing is considered as a possible means of reducing the negative impacts of these secondary metabolites of fungi on agri-food (e.g., cereals) production. In this study, the efficacy of three food processing techniques (dehulling, fermentation and nixtamalization) and one animal feed processing technique (ammoniation) for the reduction of mycotoxins in cereals (maize and sorghum) consumed in SSA as well as their influence on the quality of the processed cereals were investigated. Six objectives leading to five development chapters (aside from Chapters One and Seven) were achieved to meet the research aim. Chapter One provides the study background and outcome of the literature reviewed, while Chapter Seven gives the major conclusions. Mycotoxins, plant metabolites, and minerals analyses of the samples were achieved using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS), gas chromatography coupled to high resolution time-of-flight mass spectrometry (GC-HR-TOF/MS), and inductively coupled plasma technology, respectively. The first development chapter (Chapter Two) explains the influence of traditional fermentation procedures [cold (with changed and unchanged steeping liquor, CSL and USL, respectively), Fon and Goun procedures] on mycotoxins reduction and metabolites profile of ogi, a fermented maize product. Cold and Goun fermentation procedures were found to reduce aflatoxin B1 (AFB1) content of the experimental raw maize to below the European Union (EU) maximum limit of processed maize for human consumption. Application of metabolomics showed that the fermented maize product (ogi) obtained via the cold (USL) and Fon fermentation procedures had the highest concentrations of most of the detected metabolites, while the Goun fermentation procedure gave the least number of compounds. The investigation also revealed the potential of the selected natural fermentation procedures to reduce mycotoxin levels in maize although there were not any statistically significant differences (p > 0.05) in their effectiveness to reduce fumonisin B1 (FB1), B2 (FB2), B3 (FB3), deoxynivalenol (DON), sterigmatocystin (STERIG) and zearalenone (ZEN) levels...
D.Tech. (Food Technology)