Browsing by Author "Ntwenya, J."

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Contribution of minerals from fresh kidney bean leaves and grains in meals consumed in East, South and Central Africa
(African Scholary Science Communications Trust, 2012-08) Mamiro, P. M.; Nyagaya, M.; Mamiro, D. P.; Jumbe, T.; Ntwenya, J.; Bundara, N.
Varieties of legumes are recognized as an important source of protein and dietary minerals by a number of ethnic groups in East, South and Central Africa. Among the legume that is preferred by most Africans are the bean varieties. Beans are consumed in many forms: the young leaves, green pods, and fresh bean grains are used as vegetables; dry bean grains are used in various food preparations, and both are used as relish or side dishes together with the staple food. Apart from alleviating food insecurity, the bean leaves, green bean pods and fresh bean grains are good sources of micronutrients especially iron and zinc. Thirty eight varieties of beans deemed to be rich in minerals iron and zinc collected from a number of locations in East and Central Africa were brought from University of Nairobi and multiplied at Sokoine University of Agriculture, Morogoro. Bean leaves and fresh beans grains were picked for analysis after the plants reached three weeks and two months, respectively. Iron and zinc content was determined by atomic absorption spectrophotometer after ashing the samples. Analysis showed that leaves had significantly (P<0.05) more iron than the fresh bean grains. For bean leaves, Maharagi soja had the highest level of iron (1653.9 mg/100g) followed by Nain De Kiondo (1061.1 mg/100g). Similarly, Maharagi soja had the highest level of zinc (40.8 mg/100g), followed by Kiangara (40.5 mg/100g). Variety HRS 545 fresh bean grains, had the highest level of iron (1114.0 mg/100g) followed by Ituri Matata (983.4 mg/100g) while highest zinc content was found in HRS 545 (41.1 mg/100g) followed by RWR 10 (41.1 mg/100g). These levels of minerals are significantly higher than the average amount found in dry bean grains (Fe 5.6 – 8.0 mg/100g) and (Zn 1.7 - 2.0 mg/100g). Creating more awareness and encouraging the utilization of bean leaves and fresh bean grains will contribute in alleviating micronutrient deficiencies especially among the vulnerable groups such as children, pregnant and lactating women, and resource-poor families.
Effect of cooking on tannin and phytate content in different bean (Phaseolus vulgaris) varieties grown in Tanzania
(Academic Journals, 2017) Mamiro, P. S.; Mwanri, A. W.; Mongi, R. J.; Chivaghula, T. J.; Nyagaya, M.; Ntwenya, J.
Phytates and tannins are present in varying proportions in legume based foods. Investigation on the effect of cooking on tannins and phytates was carried out on thirty eight raw and cooked bean (Phaseolus vulgaris) varieties. Tannins were assayed by vanillin-hydrochloric acid method, while phytates were determined by a method developed by Haugh and Lantzsch. There was a very high significant difference (P≤0.00001) in the tannin concentrations between the raw and cooked bean samples. The mean tannin content for the raw and cooked samples was 1.168±0.81 and 0.563±0.503%CE, respectively. Reduction of tannins after cooking ranged from 20%CE in M’mafutala to 81%CE in GLP 2 with an average reduction of 56.3%CE. Equally, there was a very high significant difference (P≤0.0001) in the phytate concentrations between the raw and cooked bean samples. The mean phytate content for the raw and cooked samples were 0.0219±002 and 0.0122±003 μg/mL, respectively. Cooking reduced the anti-nutritional factors significantly (p≤0.0001). The extent of antinutritional factors reduction varied between bean varieties. Cooking is therefore important for mineral absorption during digestion process in humans as it makes the minerals less bound and hence physiologically available.
Household food insecurity and associated factors in rural communities: a case of Kilosa District, Tanzania
(African Journal of Agricultural Research, 2015) Ntwenya, J.; Kinabo, J.; Msuya, J.; Mamiro, P.; Mamiro, D.; Katalambula, L.
Food insecurity continues to be a major contributing factor to nutrition insecurity in developing countries. A nine item Household Food Insecurity Access Scale (HFIAS) was administered twice to 307 households among three agro-ecological zones in rural communities of Kilosa District-Tanzania to measure food security. Households were surveyed once during the rainy season (February–May) and once immediately post harvest (September–October) in the year 2011. The mean HFIAS score was the highest during the rainy season (8.15±6.06) and ranged from 0 to 26. During the harvest season, the mean HFIAS was 6.76±5.88 and ranged from 0 to 24. Using the categorical measure of food insecurity, the proportion of food secure households was higher during harvest season (31.3%) than was the case 19.9% during the rainy season. Similarly, 31.6% of the surveyed households were classified as being most food insecure during the rainy season as opposed to 26.1% during the harvest season (P=0.01). Food insecurity persisted among 39.2% of the surveyed households during the rainy season and period after harvest. The households in which at least one member offered casual labour such as the clearance of the farm fields, had 2.1 higher odds (95% CI: 1.05 to 4.29) of being food insecure. A substantial proportion of the surveyed households were food insecure across agricultural seasons and in various agro-ecological zones.