Browsing by Author "Nyirenda, D."
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Item Farmer Preference, Utilization, and Biochemical Composition of Improved Cassava (Manihot esculenta Crantz) Varieties in Southeastern Africa( Economic Botany, 2015-03) Chiwona-Karltun, L.; Nyirenda, D.; Mwansa, C.N.; Kongor, J.E.; Brimer, L.; Haggblade, S.; Afoakwa, E.O.Farmer Preference, Utilization, and Biochemical Composition of Improved Cassava (Manihot esculenta Crantz) Varieties in Southeastern Africa: Cassava (Manihot esculenta Crantz) varieties are ethnobotanically classified by farmers into two distinct classes—“sweet” or “bitter”—based on their taste, most often reflecting the inherent cyanogenic glucoside potential and intended end use. Varietal preference based on general utilization as well as more targeted end use for preferred local and improved varieties is poorly understood and not well documented. The objectives of this study were to investigate prevailing varietal preferences based on utilization and the biochemical composition of local and recently improved cassava varieties. Interviews were conducted with farmers to document the existing varieties, their origin and taste classification, and processing in relation to end use. Biochemical composition was determined for flour samples with particular emphasis on color and perceived dryness. Of the nine varieties identified, four were classified as local, while the rest were classified as improved varieties. Two varieties were classified as bitter, and the rest were classified as sweet based on end use. The classification dichotomy based on taste is an important factor in determining potential toxicity. Labile varieties that are easily affected by microenvironmental factors were classified as bitter. Reasons for preference and utilization focus as much on the leaves for use as vegetables as on the roots. The taste classification of the roots determines how and whether they are to be processed. The varieties “Mweulu” and “Tanganyika” were perceived by farmers as having excellent characteristics for making the staple dish “nshima,” reflected by their high carbohydrate contents. The variety “Bangweulu” was identified as having “bigger and starchier” roots in interviews, and the biochemical assay verified these observations. The flour sample analysis revealed crude protein content ranged from 4.86% to 7.09%. Cluster and principal component analyses showed four groupings, with the single Malawian variety exhibiting the greatest differences from the Zambian clones, while the improved varieties bred from a single mother line displayed the closest similarities. The high energy and carbohydrate values of the nine varieties provide a good basis for acceptance; however, factors such as shelf life, storage, and other postharvest qualities such as susceptibility to weevil attacks also play a determining role in the acceptance of improved cassava varieties. © 2015, The New York Botanical Garden.Item Improved outcome at end of treatment in the collaborative Wilms tumour Africa project(John Wiley and Sons Inc., 2018-01) Israels, T.; Paintsil, V.; Nyirenda, D.; Kouya, F.; Mbah Afungchwi, G.; Hesseling, P.; Tump, C.; Kaspers, G.; Burns, L.; Singh Arora, R.; Chagaluka, G.; Nana, P.; Renner, L.; Molyneux, E.Background: The Collaborative Wilms Tumour (WT) Africa Project has implemented an adapted WT treatment guideline in sub-Saharan Africa as a multi-centre prospective clinical trial. A retrospective, baseline evaluation of end-of-treatment outcome was performed for a 2-year period prior to the introduction of this guideline. The collaborative project aims to reduce both treatment abandonment and death during treatment to less than 10% for improving survival. Procedure: All participating centres obtained local Institutional Research Board (IRB) approval and implemented the adapted WT treatment guideline. End-of-treatment outcome was documented for 2 years. It was divided into alive without evidence of disease, treatment abandonment, death during treatment and persistent disease. The outcome of children enroled in the first 2 years of the prospective clinical trial has been compared to the outcome before the start of the project. Results: One hundred twenty-two patients were included in the baseline evaluation (2011–2012) and 133 in the first 2 years of the collaborative clinical trial (2014–2015). The percentage of patients alive without evidence of disease at the end of treatment increased from 52% (63/122) to 68% (90/133; P = 0.01). Treatment abandonment decreased from 23% (28/122) to 13% (17/133; P = 0.03). Death during treatment decreased from 21% (26/122) to 13% (17/133; P = 0.07). Conclusion: This collaboration, using relatively simple and low-cost interventions, led to a significant decrease in treatment abandonment and increase in survival without evidence of disease at the end of treatment. © 2018 Wiley Periodicals, Inc.Item Varietal diversity and processing effects on the biochemical composition, cyanogenic glucoside potential (HCNp) and appearance of cassava flours from South-Eastern African region(International Food Research Journal, 2015) Chiwona-Karltuna, L.; Afoakwa, E.O.; Nyirenda, D.; Mwansa, C.N.; Kongor, E.J.; Brimer, L.Changes in biochemical quality and cyanogenic safety in flours from different cassava varieties grown within the South-eastern African region as influenced by processing technique were investigated. Two local (Mweulu and Tanganyika) and four improved Cassava Mosaic Disease (CMD)-tolerant cassava varieties (Chila A, Chila B, Bangweulu and Kampolombo) were processed using different processing techniques (chipping, grating and soaking). Flours obtained from these products were studied for changes in their starch content, total, reducing and non-reducing sugars, colour and cyanogenic potential (HCNp) using standard analytical methods. The results showed that the different processing techniques had only minimal but significant (p<0.05) effects on the starch and sugar content of the different cassava varieties. Flour made from chips from all six cassava varieties had relatively high cyanogenic potentials with values ranging between 30.1 mg HCN/kg in Chila A to 64.3 mg HCN/kg in Bangweulu. Grating and soaking of the roots, however resulted in drastic reductions in the levels of the cyanogenic glucosides in all the varieties. The high HCNp levels in the chips from Chila A and Bangweulu were reduced to 16.2 and 13.5 mg HCN/kg by the grating and soaking treatments respectively. Similar reductions in HCNp levels were noted for all the other varieties. Likewise, grating and soaking also caused significant (p<0.05) increase in the L*-values of the cassava flours compared to the cassava chip flours. Soaked Kampolombo had the highest L*-value of 78.40 suggesting that the soaked Kampolombo cassava sample was whiter than the rest of the samples. These findings have implications for the preference and adoption of cassava varieties where the colour of the flour is deemed to be important for the preparation of preferred dishes.