Efficacy of selected processing techniques in mitigating mycotoxin contamination of maize and sorghum products in sub-Saharan Africa

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

Effect of selected cooking ingredients for nixtamalization on the reduction of Fusarium mycotoxins in maize and Sorghum

Although previous studies have reported the use of nixtamalization for mycotoxins reduction in maize, the efficacy of calcium hydroxide and other nixtamalization cooking ingredients for mycotoxin reduction/decontamination in sorghum and other cereals still need to be determined. The current study investigated the effect of five nixtamalization cooking ingredients (wood ashes, calcium hydroxide, sodium hydroxide, potassium hydroxide, and calcium chloride) on the reduction of Fusarium mycotoxins in artificially contaminated maize and sorghum using liquid chromatography-tandem mass spectrometry. All tested cooking ingredients effectively reduced levels of mycotoxins in the contaminated samples with reduction initiated immediately after the washing step. Except for the calcium chloride nixtamal, levels of fumonisin B1, B2, and B3 in the processed sorghum nixtamal samples were below the limit of detection. Meanwhile, the lowest pH values were obtained from the maize (4.84; 4.99), as well as sorghum (4.83; 4.81) nejayote and nixtamal samples obtained via calcium chloride treatment. Overall, the results revealed that the tested cooking ingredients were effective in reducing the target mycotoxins. In addition, it pointed out the potential of calcium chloride, though with reduced effectiveness, as a possible greener alternative cooking ingredient (ecological nixtamalization) when there are environmental concerns caused by alkaline nejayote

Phytochemicals and Amino Acids Profiles of Selected sub-Saharan African Medicinal Plants’ Parts Used for Cardiovascular Diseases’ Treatment

For years, the focus on the lipid–atherosclerosis relationship has limited the consideration of the possible contribution of other key dietary components, such as amino acids (AAs), to cardiovascular disease (CVD) development. Notwithstanding, the potential of plant-based diets, some AAs and phytochemicals to reduce CVDs’ risk has been reported. Therefore, in this study, the phytochemical and AA profiles of different medicinal plants’ (MPs) parts used for CVDs’ treatment in sub-Saharan Africa were investigated. Fourier-transform infrared analysis confirmed the presence of hydroxyl, amino and other bioactive compounds’ functional groups in the samples. In most of them, glutamic and aspartic acids were the most abundant AAs, while lysine was the most limiting. P. biglobosa leaf, had the richest total branched-chain AAs (BCAAs) level, followed by A. cepa bulb. However, A. cepa bulb had the highest total AAs content and an encouraging nutraceutical use for adults based on its amino acid score. Principal component analysis revealed no sharp distinction between the AAs composition of MPs that have found food applications and those only used medicinally. Overall, the presence of medicinally important phytochemicals and AAs levels in the selected MPs’ parts support their use for CVDs treatment as they might not add to the AAs (e.g., the BCAAs) burden in the human body

Ethnopharmacological Study of Medicinal Plants Used for the Treatment of Cardiovascular Diseases and Their Associated Risk Factors in sub-Saharan Africa

Cardiovascular diseases (CVDs) are the leading cause of global mortality, including deaths arising from non-communicable diseases in sub-Saharan Africa (SSA). Consequently, this study aimed to provide details of medicinal plants (MPs) employed in SSA for the treatment of CVDs and their related risk factors to open new avenues for the discovery of novel drugs. The extensive ethnopharmacological literature survey of these MPs in 41 SSA countries was based on studies from 1982 to 2021. It revealed 1,085 MPs belonging to 218 botanical families, with Fabaceae (9.61%), Asteraceae (6.77%), Apocynaceae (3.93%), Lamiaceae (3.75%), and Rubiaceae (3.66%) being the most represented. Meanwhile, Allium sativum L., Persea americana Mill., Moringa oleifera Lam., Mangifera indica L., and Allium cepa L. are the five most utilised plant species. The preferred plant parts include the leaves (36%), roots (21%), barks (14%), fruits (7%), and seeds (5%), which are mostly prepared by decoction. Benin, Mauritius, Nigeria, South Africa, and Togo had the highest reported use while most of the investigations were on diabetes and hypertension. Despite the nutraceutical advantages of some of these MPs, their general toxicity potential calls for caution in their human long-term use. Overall, the study established the need for governments of SSA countries to validate the efficacy/safety of these MPs as well as provide affordable, accessible, and improved modern healthcare services

Influence of nixtamalization cooking ingredients on the minerals composition of nixtamalized maize and sorghum

Nixtamalization is one of the identified processing techniques to reduce mycotoxins contamination in food. In this study, the effect of five nixtamalization cooking ingredients (wood ashes, calcium hydroxide, sodium hydroxide, potassium hydroxide and calcium chloride) on the minerals composition of maize and sorghum was investigated using inductively coupled plasma technology. Cooking of maize and sorghum with sodium hydroxide, calcium hydroxide and potassium hydroxide respectively gave rise to significantly (p < 0.05) highest concentration of Na, Ca, and K with all the cooking ingredients having a reducing effect on P. Maize samples cooked with potassium hydroxide had the highest level of most of the considered essential trace elements while for sorghum, wood ashes treatment brought about the richest level of Mn, Zn and V. Although some of the nixtamalized samples had unsafe Na/K ratio (sodium hydroxide treatment samples) and Al levels (wood ashes treatment samples), they all had their Cd and Pb contents below the FAO/WHO Codex Alimentarius recommended maximum levels. Generally, the study revealed that potassium hydroxide is an ideal cooking ingredient to address the low concentration of Cu, Zn and Fe common in tortillas while removal of pericarp during nixtamalization may not always bring about loss of dietary minerals

Influence of traditional dehulling on mycotoxin reduction and GC-HRTOF-MS metabolites profile of fermented maize products

Contamination with mycotoxins has been a worldwide food safety concern for several decades, and food processing has been suggested as a potential method to mitigate their presence. In this study, the influence of traditional dehulling (TD) on the mycotoxin reduction and metabolites profile of fermented white maize products obtained via natural and three controlled fermentation methods (involving Lactobacillus fermentum, Lactobacillus plantarum, and their mixed cultures) was examined. Gas chromatography coupled with high resolution time-of-flight mass spectrometry (GC-HRTOF-MS) and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) were employed. TD brought the levels of fumonisin B1 (FB1) and B2 (FB2) in the white maize below the regulatory limit set by the European Union (EU) for maize consumed by humans. While TD increased the concentration of several mycotoxins in the fermented maize products obtained from other studied fermentation methods, it primarily reduced aflatoxin B1 (AFB1), FB1, deoxynivalenol, and 15-acetyldeoxynivalenol in the L. plantarumfermented products. By tempering the dehulled maize, a solid-state fermentation process began. This was used in TD to make it easier to remove the pericarp. GC-HR-TOF-MS metabolomics revealed that TD brought about the generation of 12 additional compounds in the dehulled maize though some metabolites in the whole maize were lost/biotransformed. The fermented dehulled maize products obtained from the four studied fermentation procedures contained fewer compounds than the fermented whole maize products. Overall, the analysis showed that all fermented maize (whole and dehulled) produced had varied nutritional metabolites and mycotoxin concentrations below the EU maximum level, except for fermented maize obtained from mixed strains (AFB1 + AFB2 > 4.0 g/kg)

Mycotoxin reduction and metabolite profiles of ogi produced using traditional fermentation methods

Mycotoxins are widely present in maize, a favourite staple food in sub-Saharan Africa. Food processing methods, like fermentation, have been suggested as potential ways to reduce mycotoxin contamination levels in the grain and, as a result, limit the exposure of crop consumers to the harmful effects of the toxins. The influence of four traditional fermentation processes [cold (with changed steeping liquor (CSL) and unchanged steeping liquor (USL), Fon and Goun procedures] on the mycotoxin reduction and metabolites profile of ogi, a fermented maize product, was studied. Ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and gas chromatography linked to high resolution time-of-flight mass spectrometry (GC-HR-TOF-MS) were respectively employed for the mycotoxin and metabolite profiles analyses of the samples. Among the nine mycotoxins detected in the raw maize samples, aflatoxin B1 (AFB1) and fumonisin B1 (FB1) + fumonisin B2 (FB2) concentrations were found to exceed the European Union (EU) maximum limit. Both cold (containing USL and CSL) and Goun fermentation techniques were able to lower the AFB1 concentration below this threshold. The metabolomics result revealed that ogi produced using the cold (USL) and Fon fermentation processes had the highest number of most of the detected important compounds, whereas the Goun fermentation process produced the fewest compounds in total. There was no statistically significant difference in the ability of the specified natural fermentation processes to lower FB1, FB2, FB3, deoxynivalenol (DON), sterigmatocystin (STERIG), and zearalenone concentrations in maize (ZEN). In addition, the results demonstrated that the four natural fermentation processes evaluated had varying effects