Browsing by Author "Kyamuhangire, William"

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    Amaranth Leaves and Skimmed Milk Powders Improve the Nutritional, Functional, Physico-Chemical and Sensory Properties of Orange Fleshed Sweet Potato Flour
    (Foods, 2019) Ampek Tumuhimbise, Gaston; Tumwine, Gerald; Kyamuhangire, William
    Vitamin A deficiency (VAD) and under nutrition are major public health concerns in developing countries. Diets with high vitamin A and animal protein can help reduce the problem of VAD and under nutrition respectively. In this study, composite flours were developed from orange fleshed sweet potato (OFSP), amaranth leaves and skimmed milk powders; 78:2:20, 72.5:2.5:25, 65:5:30 and 55:10:35. The physico-chemical characteristics of the composite flours were determined using standard methods while sensory acceptability of porridges was rated on a nine-point hedonic scale using a trained panel. Results indicated a significant (p < 0.05) increase in protein (12.1 to 19.9%), iron (4.8 to 97.4 mg/100 g) and calcium (45.5 to 670.2 mg/100 g) contents of the OFSP-based composite flours. The vitamin A content of composite flours contributed from 32% to 442% of the recommended dietary allowance of children aged 6–59 months. The composite flours showed a significant (p < 0.05) decrease in solubility, swelling power and scores of porridge attributes with increase in substitution levels of skimmed milk and amaranth leaf powder. The study findings indicate that the OFSP-based composite flours have the potential to make a significant contribution to the improvement in the nutrition status of children aged 6–59 months in developing countries.
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    Association between accumulation of total cyanogens and progression of cassava mosaic disease in cassava (Manihot esculenta Crantz)
    (Uganda J. Agric. Sci, 2006) Tumwesigye, Steven Kashub; Baguma, Yona.; Kyamuhangire, William; Mpango, George
    Cyanogenic plants, such as cassava, exhibit genetic resistance to diseases and pests, which is associated with a general defence signalling mechanism that responds to stress situations. Cyanogens in cassava vary diversely with cultivar, stress, location, environment and plant age. Factors that induce plant stress often result in increased total cyanogens. Interestingly though, increased total cyanogens often associate with increased resistance to stress. This overlap between plant defence systems and plant stress is not coincidental. The infection of cassava with diseases and pests not only affects yields, but also influences the level of total cyanogens, which are presumed to be a part of the plant defence system. To qualify the extent to which total cyanogens are influenced by cassava mosaic disease (CMD), the effects of CMD status, cultivar resistance and plant vigour on total cyanogens accumulation in cassava at different growth stages of the crop was investigated. A total of 436 cassava plants were studied in the field and greenhouse, representing three different CMD status categories i.e., resistant, moderately susceptible and highly susceptible genotypes. Associated cyanogenic potential (CNp) levels were determined using standard protocols. CMD and CNp were shown to be highly associated (r = 0.90, P d” 0.001 for variety; Pd” 0.003 for CMD) suggesting a role of CNp in the defence mechanism against CMD infection. Notably, lower cyanogen levels occurred in vigorous highly susceptible cassava than in the non-vigorous highly susceptible (most stressed), suggesting a positive correlation between stress level and CNp content. The results of the greenhouse studies matched with those from the field further supporting the observed association between CMD and CNp (P d” 0.001), although, CNp levels were lower than in field trials (by 19.3 fold for roots and 6.3 fold for leaves) possibly due to temperature and nutrition effects. Future studies including understanding of the genetic link between CNp and CMD, interaction between vigour x variety x CMD status, effects of seasonality on CNp accumulation, temperature regimes and nutrition on CNp yield, together may further our knowledge and capacity to control CMD.
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    Characterisation of banana wine fermented with recombinant wine yeast strains
    (American Journal of Food and Nutrition, 2013) Byaruagaba-Bazirake, George William; Pierre, van Rensburg; Kyamuhangire, William
    Commercial enzyme preparations are applied in the process of winemaking to improve wine processing and wine quality. In this study, three recombinant wine yeast strains that had been developed to improve wine processing were compared with regard to their ability to produce banana wine of an acceptable quality. The recombinant wine yeast strains contain genes coding for enzymes able to degrade different polysaccharides (glucan, xylan, pectin and starch). The recombinant strains were able to induce higher wine yields from the fermented banana pulp vis-à-vis the control. The wines obtained with the recombinant strains and the untransformed control did not show significant differences (p>0.05) in their physicochemical parameters. The highest wine yield obtained from the pulp which was treated with genetically modified yeast (recombinant yeast strain) secreting glucanase and xylanase enzymes (plasmid pDLG39) was 69.5% v/w prepared from Bogoya pulp. This wine yield was higher than the control yield (65.9± 0.07) by an increase of 5.5% v/w. However, the wine from Kayinja pulp which was treated with genetically modified yeast secreting pectinase enzyme(plasmid pPPK) yielded wine (60.3±0.28% v/w) with 35% increase compared to the wine (44.7±0.49) obtained with the control yeast. The recombinant yeast strains compared in this work secreted enzymes playing a similar role to that of the previously studied pectinolytic commercial enzymes. Therefore, such a recombinant yeast strain could be used in banana wine fermentations as an alternative to commercial enzyme preparations