Browsing by Author "Shayo, N. B"

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Colour and antioxidant activities of honey from different floral sources and geographical origins in Tanzania
(Tanzania Journal of Agricultural Sciences, 2016) Shekilango, S. G; Mongi, R. J; Shayo, N. B
Honey is a sweet, yellowish liquid that is produced by honey bees and it has been used for many years for nutrition and therapeutic purposes. Its therapeutic potential has been associated to its antioxidant capacity which plays an important protective role in human health through scavenging of free radicals in the human body and thereby decreases the amount of free radical and damage to biological molecules like lipids and DNA. This study was carried out to investigate the effect of floral source (miombo and acacia) and geographical origin (Central, Coastal, Lake, Northern, and Southern Highland) in mainland Tanzania on colour and antioxidant activity of honey samples. Colour, total flavonoids content (TFC), total phenol phenolic contents (TPC) and antioxidant activities of the samples were evaluated using UV/Vis spectrophotometer, Folin-Ciocalteu reagent and Ferric Reducing Antioxidant Power (FRAP) methods respectively. There were significant (p<0.05) differences in all parameters assessed between floral sources. Miombo honey samples had higher pfund values (mm) for colour ranged from 31.55 mm (white) to 143.98 (dark amber) than acacia samples with values ranged from 17.33 (extra white) to 62.28 mm (light amber). Miombo samples had higher TFC values of 13.5±0.25-39.9±0.42 mgRE/100g DM) and TPC of 127.9±2.5-395.2 mg GAE/100g DM) than acacia samples with values of 12.7±0.60-17.5±0.38 mgRE/100g DM and 119.5-168.2 mg GAE/100g DM respectively. Similarly, significantly (p<0.05) highest and lowest FRAP values of 488.9-956.3 and 252.6-368.26 μM Fe2+/100g DM were observed in Miombo and acacia honey samples respectively. Moreover, variations in colour, TFC, TPC and FRAP between zones were significant (p<0.05). Within the miombo samples, northern and coastal zones had respective lowest and highest values whereas central and northern zones had respective lowest and highest values within the acacia samples. A strong correlation (R2= 0.942) between TPC and antioxidant activities of honey samples suggest that the antioxidant of honey is highly linked to TPC. Therefore, the study has revealed that, floral sources and geographical origins have varied significant effects on colour, flavonoids, total phenols and antioxidant activities of Mainland Tanzania honey. Honey samples from miombo floral source had higher antioxidant activities and hence their consumption is more recommended.
Isolation and characterisation of yeasts and bacteria from Mbege- An opaque Beerr made from millet malt and banana juice
(Tanzania J. AgriC. Sc, 1998) Shayo, N. B; Nnko, S. A. M; Gidamis, B
The micro organism involved in the traditional fermentation process of "mbege ",an indigenous Tanzanian alcohol beverage prepared from malted millet and banana juice were isolated and identified saccharomyces cerrevisiae and lactobacillus plantarum whereidentified as yeast and bacteria responsible for the fermentantion process respectivelly. The main spoilage micro-organism of Mbege was identified as of Acetobacter species. A diverse range of micro-organisms were also identified in the mlliet malt .The coliforms were the predominant ones followed by pseudomonads, lactic acid bacteria(LAB) and yeasts. The presence of high numbers of coliforms (l.98+0.20x 107 ) in millet malt poses no health risk as they are destroyed during porridge preparation. In addition the low PH ( ph4.5 ) of mbege in hibits the growth of coliforms and other pathogenic bacteria. The diverse range of micro-organisms founds in millet malt was an indication of unhygienic handling of millet malt,
Sensory evaluation of different preparations of cassava leaves from three species as a leafy vegetable
(African Journal of Biotechnology, 2013-11-13) Umuhozariho, M. G; Shayo, N. B; Sallah, P. Y. K; Msuya, J. M
Cassava leaves are largely consumed in Africa and are among the top three African indigenous vegetables rich in nutrients. Leaves from bitter (Manihot utilissima), sweet (Manihot dulcis) and wild (Manihot glaziovii) species of cassava were cooked by boiling in salted (sodium bicarbonate and table salt) water with the addition of palm oil and ground-nut paste, following processing by “pounding”, “pounding and then drying” and, “drying and then pounding”. The drying was done in tunnel solar drier at temperature of 65°C on average. Nine samples (three species x three processing methods) were evaluated by 31 panelists, using a five point hedonic scale, where 5 = like very much and 1= dislike very much. Cassava species affected significantly (p = 0.0047; 0.0206) scoring for texture and overall acceptability, respectively, but not for colour, aroma and taste. Processing method highly significantly (p< 0.0001) affected all the sensory attributes scoring. Leaves from all three species were liked as leafy vegetable, except when pounded after drying.