Articles, Conference and Workshop Papers Collection

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Erosion hazard assessment in the upper Ewaso Ng’iro basin of Kenya: application of gis, usle and eurosem
(Sokoine University of Agriculture, 1999) Mati Bancy Mbura
A methodology was developed for assessing soil erosion hazard in the Upper Ewaso Ng’iro basin of Kenya, using Geographic Information Systems (GIS), the Universal Soil Loss Equation (USLE) and the European Soil Erosion Model (EUROSEM). The USLE was used in a GIS environment by creating thematic maps of R, K, L, S, C and P and then calculating soil loss by raster-grid modelling with Arc/Info GRID. The rainfall erosivity factor (R) was derived from relationships between rainfall amount and erosivity using erosion plot data from within the catchment. The nature of the relationship was found to be a function of agi o-climatic zones of the region. Mean annual erosivities ranged from 145 to 990 J m'2 hr'1. For a given amount of rainfall, erosivity was higher in zone IV than in the wetter zones 11-111. The soil erodibility factor (K) was estimated using the USLE nomograph and data from laboratory analysis of field samples collected from representative major soil mapping units. The K-values were low to medium, ranging from 0.10 to 0.25 over 84 percent of the basin. The topographic factor (LS) was obtained by creating Digital Elevation Models (DEMs) of the basin with TOPOGRIDTOOL of Arc/Info. These were then used to determine the slope steepness and length factor values, calculated with raster-grid modelling. Although DEMs proved a useful tool, maximum values of both steepness and length had to be set in this reconnaissance study to achieve reasonable results. A finer resolution of input data and a smaller grid cell size are needed for accurate determination. The cover and management factors (C) were obtained by determining the land cover types within the basin using remotely sensed data (SPOT 1 colour composite prints) and ground truthing studies. The factor values were estimated from USLE guide tables and measurements of cover from plots and test sites. Some 70 percent of the basin is covered by rangelands. The conservation practice (P) factor values were estimated from USLE guide tables and then applied to areas where soil conservation had been introduced /?. M. Mali PM > Thesis 1999 Silsoe College Cranfield .■Ihstract •'university II according to maps obtained from the Ministry of Agriculture. The USLE was validated using data from erosion plots. A value of R2 = 0.645 was obtained between predicted and measured values but the standard error was rather high (e = 5.745 t ha'1 yr'1). Using an annual soil loss of 9.0 t ha'1 yr'1 as tolerance level, some 36 percent of the basin was found to experience unacceptably high erosion rates. Most of this area was communal grazing land and cropland where soil conservation measures had not been applied. A critical land cover type within the grazing land is shrubland, where vegetation cover is less than 40 percent and high erosion risk was predicted and confirmed by field surveys. EUROSEM could not be integrated within a GIS in the time available for research. It was therefore simulated outside GIS environment, where it was applied to Embori and Mukogodo plot data using separate data sets for calibration and validation. Calibration was used to obtain input parameters for saturated hydraulic conductivity, cohesion and Manning’s roughness coefficients. Validation gave correlation coefficients of 0.907 and 0.840 for predictions of storm runoff and soil loss respectively at Embori; the corresponding values for bare soil plots at Mukogodo were 0.895 and 0.577. However, EUROSEM predicted runoff poorly (R2 = 0.570) and failed to predict soil loss at all the vegetated plots at Mukogodo. The model was applied to simulated vegetation covers of barley, maize, grass and forest for a 36.7 mm rainstorm at Embori. The simulated soil losses showed an exponential decrease with increasing cover. At a threshold cover of 70 percent, soil loss diminished to zero under grass and forest and decreased to a minimum value under barley and maize. These results support the USLE simulations, which showed that areas with more than 70 percent cover (such as forest) had a low erosion hazard, even with steep slopes and high rainfall erosivities. This research has demonstrated that GIS can be used with the USLE to assess and quantify erosion hazard, giving results that can be used for conservation planning. EUROSEM can be applied successfully to bare soil and cropland, but application to other land covers requires further investigation. Land cover and topography are the main factors controlling the spatial distribution of soil loss in the Upper Ewaso Ng’iro basin. Future conservation activities should be concentrated on the rangelands.
The impacts of frozen storage and fatty acid oxidation on silver carp myofibrillar protein functionality
(Jiangnan University, Wuxi, JiangsuProvince, P.R., 2006) Mlyuka, Erasto
Silver carp (Hypophthalmichthys molitrix) is a freshwater species living in temperate conditions (6-28 °C) and its natural distribution is in Asia. It is generally cultured and marketed locally alive or fresh in most of the producing countries. China is the largest producer of silver carp in the world; however, its market price is relatively low compared to most other species, normally costs 8-10Yuan/kg. In order to keep the product longer and further extend the markets instead ofjust consuming it fresh, processing technologies for adding value and frozen storage are of significantly important for this fish species. In this thesis, the report is mainly focused on the study done on isolation of myofibrillar protein from silver carp; exposing the isolated myofibrillar protein to oxidative environment simulated using an iron oxidation model system to mimic the oxidative stress during processing and frozen storage. Also the impacts of the iron oxidation model system, fatty acid oxidation and frozen storage on protein functionality of silver carp myofibrillar protein isolate were evaluated. Oxidative damage to silver carp myofibrillar proteins isolate (MPI) was investigated by measuring changes in physico-chemical, and functional properties after exposure to iron-catalyzed oxidation system (IOS). Iron oxidized MPI exhibited an increase in carbonyl content and dityrosine, which were significant and negatively correlated with protein solubility (PS) (r=0.85), (r=0.80) and gel strength (GS) (r=0.95), (0.93), respectively, however the decrease in total thiol group content was significantly and positively correlated with PS (r=0.77) and GS (r=0.89). These led to significant changes (P<0.05) observed in the protein and functional properties of oxidized MPI. Sodium dodecyl sulfatepolyacrylamide gel electrophoresis demonstrated that IOS resulted in a major loss of myosin and actin associated with formation of protein polymers as supported by gel-permeation chromatography (GPC) results. The total fat content of silver carp MPI was 0.6%, it is mainly composed of unsaturated fatty acids of which about 34% constituted by eicosapentaenoic acid, ( 2O:5co-3), docosahexaenoic acid, ( 22:6co-3), and linolenic, ( 18: 3m-3) as the main co-3 poly-unsaturated fatty acids (PUFAs) as well as linoleic acid, (18:2co-6) and arachidonic acid, (20:4co-6), the main co- 6 PUFAs in fish , unfortunately PUFAs are prone to oxidation producing reactive oxygen species capable of modifying protein structure. This study suggests that the decreased functionality of proteins in muscle foods exposed to an oxidative environment could be due to chemical and physical changes resulting from oxidation reactions. It was found that silver carp myofibrillar protein is susceptible to an iron-catalyzed oxidation causing a significant loss of its functionality, thus a study was carried out to iii Jianenan University, M.Sc Thesis, 2010 Abstract determine the susceptibility of silver carp protein to natural oxidants (fatty acids or fatty acids oxidation products) in frozen storage with respect to its functionality. Frozen stored myofibrillar protein isolate with 0.6M NaCl or myofibrillar protein isolated from previous frozen stored whole fish and fish mince of silver carp at -18°C for 90 days were assessed for protein and lipid oxidation with regard to protein functionality. The addition of sodium chloride to 0.6M at pH6.5 improved protein functionality especially water holding capacity of frozen stored myofibrillar protein isolate from 5.3 to 6.4mL/g MP1 after 90 days of frozen storage. However, the differential scanning calorimeter results showed that, sodium chloride significantly increased thermal susceptibility of myosin from 48.12 to 46.40°C with 0.1M NaCl and 0.6M NaCl frozen stored for 90 days, respectively. Whole fish frozen storage was more susceptible to oxidation compared to fish mince and myofibrillar protein isolate due to their different lipid content. On contrary, myofibrillar isolated from frozen whole fish showed significant changes in protein functionality may be due to great loss of amino acid such as cysteine, lysine, histidine and methionine during frozen storage. On the other hand investigation was done on stabilization and oxidation protection of silver carp MP1 stored at -18 °C, 90 days and composed of MPI, 8% cryoprotectants (4% sucrose and 4% sorbitol) with or without antioxidants (0.2% ascorbate, 0.2% a- tocopherol, or their combination) and packed in a polyethylene bag, sealed under air. MPI without cryoprotectants and antioxidants was the control. Compared with the control, cryoprotectants increased PS (protein solubility), WHC (water holding capacity), OHC (oil holding capacity), EC (emulsification capacity) and GS (gel strength), also, the cryoprotectants and/or antioxidants decreased MPI oxidation susceptibility as well as susceptibility of myosin to thermal denaturation. After 30 days of frozen storage, there were no significant differences ((P>0.05) of storage time on alteration of protein functionality and actin susceptibility to thermal denaturation between cryoprotectants and the control. Antioxidants minimized oxidation effects on MPI frozen storage. Therefore, the present study reveals that, improvement in the functional properties of silver carp MPI were greatly influenced by cryoprotectants and antioxidants, this reflect a great role played by sucrose/ sorbitol and antioxidants in protecting native protein structure to a greater extent owing to impact of frozen storage and oxidation respectively.
Assessment of knowledge, attitudes and practices on breastfeeding among HIV infected mothers with infants in Kibaha town council
(Sokoine University of Agriculture, 2011) RWERAMIRA,MARGARETH CLEMENT
Knowledge, Attitudes and Practices (KAP) on breastfeeding among HIV-infected mothers are important in determining the health and nutritional status of their children. The HIV pandemic and the risk of mother-to-child transmission (MTCT) of HIV, especially through breastfeeding (BF) poses special difficulties to HIV-infected mothers, their infants and the community. This study was designed to assess KAP on breastfeeding among HIV-infected mothers having children aged 0-12 months living in Kibaha Town Council. A cross-sectional, descriptive study design was employed and convenient sampling procedure was used to select the respondents. Primary data were collected using structured questionnaire which were administered by face to face interview. Data analysis was done using Statistical Package for the Social Science (SPSS) 15.0 version computer software. The study findings revealed that there is limitation in terms of KAP on BF, complementation and infant feeding options among the HIV-infected mothers. Breastfeeding was chosen by majority of respondents (96%) compared to replacement feeding (6%). About 76% of mothers ceased to practice EBF before their infants were six months old due to fear of MTCT of HIV. The study also revealed that mothers’ level of education was significantly associated with their knowledge (p = 0.00403). Mixed feeding (63.6%) and nipple cracks (77.8%) were the most known factors by the respondents to increase the risk of MTCT of HIV. Breast conditions such as sore/cracked nipples; fear of stigma; lack of counselling and follow up from the health workers; and cultural beliefs such as BF by using one breast were observed as the constraints faced by the respondents. Counselling services on infant feeding options, regular follow to mothers and more training to the counsellors on BF and PMTCT of HIV need to be strengthened
Epidemiology of tuberculosis in inmates of selected central prisons in Tanzania
(Sokoine University of Agriculture, 2014) RUGAMBA,WILSON EMMANUEL
A cross sectional study was carried out to determine prevalence of tuberculosis (TB) among prison inmates and assessed risk factors contributing to the disease in five selected Central prisons namely; Butimba, Isanga, Ruanda, Ukonga and Segerea in Tanzania. The prevalence was established based on sputum smear microscopic examination for Acid Fast Bacilli (AFB). Questionnaires were used to gather information from prison inmates and prison staff about possible risk factors for TB spread in prisons. Due to the current association between HIV infection and TB epidemic, HIV screening was carried out by testing capillary blood adhering to the National algorithm whereby two serial rapid antibody tests namely Alere Determine and Uni-Gold were used. A total of 370 prisoners out of 8330 inmates were involved and the overall prevalence of TB was 3.8%. On commencement of the survey, 71 prisoners (0.85%, n=71; N=8330) from studied prisons were under anti TB treatment. The overall prevalence of HIV in studied Prisons was 5.4%. Il was also noted that overcrowding, poor ventilation, poor prison architecture, history of TB contact, HIV infection, smoking cigarettes, and limited knowledge on TB to prisoners were the risk factors for TB in prisons. The present study confirms the high prevalence of pulmonary tuberculosis in prison populations, thus suggest not only active transmission of the disease in the prison settings but also the need for executing urgent preventive measures.
Uranium uptake by selected food groups and the associated health effects to the residents of Bahi district in Tanzania
(Sokoine University of Agriculture, 2014) MZIRAY,ZAINAB JURAJI
Assessment of Uranium levels in selected food groups and products with the associated health effects to the residents of Bahi District was carried out. The objective was to come up with information on whether these food groups contain significant amounts of Uranium and if the community has been affected by uranium related diseases. This was done to bring the awareness to the vulnerable communities and Tanzanian Government in general on the environmental and health hazards posed by the presence of Uranium deposits in the study area. Selected food groups and products used to assess uranium levels were maize, finger millet, rice. cassava leaves, salt, soda ash, fish, flamingo meat and water. These food groups were collected from three different villages of Bahi district. The levels of uranium in the named food groups and products (in pg kg-1) were determined by using ICP- OES instrument. Maize and rice had uranium concentration below detectable limit (<10), millet was found to range 11.88 - 25.13; cassava leaves ranged 12.37 - 13.83. Fish had uranium content of 17.98 in the skin where as muscles had uranium level below detactable limit. Flamingo bird had uranium level of 31.78 in the liver , where as other tested parts had below detectable limit. Soda ash was found to have uranium content of 1910, whereas salt had uranium content below detectable limit. The results for water from different sources in three villages have shown that, in Hindi village, Playa lake water had uranium concentration of 1233, while drinking water from one well had uranium content of 95.4, water from a well used for irrigation had uranium content below detectable limit. In Mpamantwa village, the water from one well had uranium content of 16.7 whereas other sources had uranium level below detectable limit. In Bahi village, the water from one well had uraniumiii level below detectable limit while river water had uranium concentration of 67.6 and another well had uranium content of 16.6. Secondary data from hospitals have shown that Bahi communities have not been affected by uranium exposure through foods consumed. However, further research need to be conducted on domestic animals since they use lllindi Playa lake water for drinking which was found to have high uranium concentration.
Detection of proteolysis in high temperatures treated milk by reverse phase high performance liquid chromatography (RP-HPLC)
(Academic Journals, 2014-02) Chove Lucy M.; Grandison S. Alistair; Lewis Michael J.; Issa- Zacharia Abdulsudi
Proteolysis of UHT milk during storage is one of the problems affecting the dairy industry worldwide. Native enzymes have been implicated as being the main cause of spoilage of such milk. In the current study, reverse phase high pressure chromatography (RP-HPLC) method was used to detect proteolysis by native enzymes in high temperature heated milk. The aim of this research was to assess susceptibility of milk to proteolysis by native enzymes, after being subjected to various temperature- time processing conditions. Samples of raw and heated milk were clarified prior to analysis. Clarification was carried out to obtain pH 4.6 and 6% TCA soluble extracts, which were injected into RP- HPLC after filtration. This method confirmed that raw milk and milk processed at 85°C /15 s were the most proteolysed, indicating that the high temperatures employed during this study (110, 120, 130 and 142°C for 2s) inactivated the native enzymes. The RP-HPLC method is a useful method for the detection of proteolysis in milk.
Effect of solar drying methods on total phenolic contents and antioxidant activity of commonly consumed fruits and vegetable (mango, banana, pineapple and tomato) in Tanzania
(Academic Journals, 2015-05) Mongi, Richard J.; Ndabikunze, Bernadette K.; Wicklund, Trude; Chove, Lucy M.; Chove, Bernard E.
The effects of solar drying methods [Cabinet direct (CDD), cabinet mixed mode (CMD) and tunnel (TD) drying] on total phenolic content (TPC) and antioxidant capacities of commonly consumed fruits and vegetable in Tanzania were investigated. The TPC and FRAP in mangoes (Mangifera indica cv. Dodo, Viringe and Kent), bananas (Musa acuminata, cv. Kisukari, Kimalindi and Mtwike), pineapples (Ananas comosuss cv Smooth cayenne) and tomatoes (Lycopersicum esculentum cv. Tanya, Cal J and Onyx) were evaluated using Folin-Ciocalteu reagent and ferric reducing antioxidant power (FRAP) methods, respectively. There were significant (p<0.05) variations in TPC (mg GAE/100 g DM) and FRAP (μmol/100 g DM) among the fresh fruit and vegetable samples. The highest TPC was in tomato (476.6±8.6 - 538.9± 1.4) and lowest in banana (139.3±2.3 - 189.2±2.7). Drying methods had significant (p<0.05) effect on TPC and antioxidant values of the samples. All fresh samples had higher TPC levels but declined significantly in dried samples with the exception of tunnel dried tomatoes. Among the dried samples, the tunnel dried samples had less TPC loss (6-16%) than the cabinet dried samples (17-42%). The cabinet direct and mixed mode samples were not statistically different (p>0.05) from each other. However, tunnel dried samples had less FRAP loss (6-13%) which were statistically different (p<0.05) from the cabinet dried samples (14-56%). Percentage TPC and FRAP recoveries (%) differed significantly (P<0.05) between the varieties within the fruits/vegetable for both drying methods. A strong 2 2 correlations between TPC and FRAP in both fresh (R = 0.970) and dried samples (R =0.8636) suggests that solar drying methods have significant effects on total phenolic contents and antioxidant activities of fruits and vegetables with tunnel drying method giving significantly less effects.
Nutritional quality and functional properties of baobab (Adansonia digitata) pulp from Tanzania
(Canadian Center of Science and Education, 2016) Aluko, Angela; Kinyuru, John; Chove, Lucy Mlipano; Kahenya, Peter; Owino, Willis
Baobab (Adansonia digitata L.) is a majestic tree associated with human habitation in some of the semi-arid regions of Africa and establishes an enormous economic and nutritional importance to the rural residential districts. The fruit pulp is considered to be of high nutritional significance; particularly vitamin C and calcium, also possess antioxidant functions as well as high dietary fiber content. Although it is a potential fruit for improving local diets and livelihoods,this fruit is underutilized and its potential not yet fully acknowledged. This work was contracted with the aim of defining the nutritional quality and functional properties of baobab pulp harvested from some selected parts of Tanzania. Results indicated that the pulp from the three locations had moisture content which ranged between 9.16% to 10.30%, fat 0.46%-1.98%, ash 4.75%-5.21%, fiber 5.91%-9.65%, protein 3.23%-3.53%, carbohydrate 80.49%-85.19, vitamin C 169.74mg/100g-231.57mg/100g, beta-carotene 2.16 mg/100g-3.19mg/100g.Fructose 0.56±0.15-0.81±0.17g/100g, glucose 0.77±0.26-0.87±0.31g/100g and sucrose 0.75±0.25-0.84±0.29g/100g. The substantial differences (p≤ 0.05) between locations were observed in fat, crude fiber, carbohydrates, and fructose. Vitamin C, beta-carotene, protein, ash, moisture, sucrose and glucose showed no significance difference (p≤ 0.05) among locations. The functional properties included emulsification, foaming and gelling properties which ranged between 37.9-45.15%, 1.85-6.57% and 11-12% respectively and were significantly different (p≤ 0.05) among locations. The results show that baobab pulp has a good content of nutrients and functional properties which can be useful in food industries.
Influence of botanic and geographic origin on quality of honey from Tanzania.
(Sokoine University of Agriculture., 2016) Shekilango, Salama Ghuio
In aview of the expanding global market, characterization of floral and geographic origins of honey has become a more important issue than ever. In general, prices of honey at the international market are set according to floral and geographic origin of the nectar, which relate to the chemical composition. This study was conducted to assess and characterize Tanzania honey from different floral origins and geographic zones based on physicochemical properties and minerals content, sugar profile, total phenol and antioxidant activities as well as sensory properties and consumer acceptability. Samples from two floral origins, Miombo and Acacia were collected from five different zones in Tanzania namely Central. Coastal. Lake. Northern and Southern zones and subjected to chemical and sensory analyses. Complete randomized block design with floral origin and geographic zones as main principal factors were used to assess the effect of these factors on stated parameters. Moisture content, ash, pH, acidity, viscosity and colour were determined as per methods described in AOAC (2005). Phenolic content was determined using modified Folin Ciocalteau method and antioxidant activity using Ferric Reducing Antioxidant Power (FRAP) assay. Sugar profile and quantification was performed using Shimadzu high- performance liquid chromatograph equipped with refractive index detector (RID-10A) as per method 977.20 in AOAC (2005). Minerals: copper, zinc, lead, iron, calcium and magnesium were determined using Atomic Absorption Spectophotometer (AAS). sodium and potassium using flame photometer as described by AOAC standard methods (2005). Quantitative Descriptive sensory analysis was done using a panel of 8 trained judges using 9 point an unstructured line scale for rating the intensity of an attribute while consumers acceptability study was done using a 9 point hedonic scale as described by Lawless and iii Heyman (2010) to evaluate acceptability for the attributes of colour, aroma, viscosity and general acceptability. Data were analysed by R software for univariate Analysis of Variances (ANOVA) to determine significant variations between the main factors. Means were separated by Tukey's Honest significant differences at p < 0.05. Multivariate Principal Component Analysis (PCA) was done by Latentix software and Cluster analysis was done by Latentix and R software to determine the systematic variations in the study variables. Most properties of honey varied significantly (p < 0.05) between geographical zones and floral origins with values of honey from Mioinbo floral origin being higher compared to honey samples from Acacia origin. Northern zone honey samples within Mioinbo origin had significantly (p < 0.05) higher moisture content, ash and acidity while Lake zone honey samples had significantly (p < 0.05) higher viscosity. Southern highland Mionibo honey samples had higher colour value on pfund scale. PCA results showed that colour and viscosity had more effect on the variability of physico chemical properties. Phenolic content (mg gallic acid equivalent/100g) and antioxidant activities as pM Fe2‘/100g were significantly (p < 0.05) higher in the Northern zone than in other zones. Honey samples from Mioinbo had significantly higher values of 127.9 - 395.2 pM Fe2+/100g than Kcacia honey samples with values of 119.5 - 168.8 pM Fe27100g between floral origins. Bi plot from principal component analysis, PCI explained 99.2% of variations and showed that both parameters (total phenol and antioxidant activity) had higher effect on the variability. A strong correlation (R2 = 0.929 and R2 = 0.869) between phenolic contents and antioxidant activities were observed in both Mioinbo and Acacia honey samples. respectively. iv There were significant differences (p < 0.05) in fructose, sucrose and total sugars between zones and floral origins. Fructose was found to be the most dominant sugar in the honey samples in each zone and floral origin with the highest contents observed in Acacia honey samples (44.7 - 47.0 g/lOOg) than their Miombo counterpart (39.5 - 42.0 g/lOOg). Glucose, the second dominant sugar was not significantly (p > 0.05) different between floral origins and among zones. Sucrose occurred in small amounts in honey samples from all zones and floral origins. The variation of each sugar between zones within each origin were also significant (p < 0.05) with Northern zone had the highest content of total sugar. PCI bi plot explained 90.7% of total variations with high contribution from fructose and total sugars. Potassium was observed to be the most abundant macro minerals in the honey samples (380.2 - 3488.1 ppm) followed by magnesium (128.1 - 2409.5 ppm), calcium (86.3 - 336.6 ppm) and sodium (78.1 - 165.3 ppm) while iron was the most abundant micro minerals (24.5 - 36.0 ppm) followed by zinc (2.5 - 8.7 ppm) and copper (0.2 - 0.5 ppm). The northern zone honey samples from both floral origins had lead contents above maximum allowed limits as per Tanzania honey standard. The variations in macro minerals between zones were significant with Northern zone having higher contents of Ca. Mg, K and Na in samples originating from Miombo floral origin. Furthermore, the variations in mineral contents between floral origins were also significant with honey samples from Miombo floral origin having significantly much higher content of minerals than Acacia honey samples. Multivariate cluster analysis revealed grouping/similarities of zones according to the mineral they contain. In quantitative descriptive analysis, variations in mean intensity scores of attributes between zones were significant (p < 0.05) in aroma, clarity, hue, viscosity and whiteness, respectively for honey samples from Miombo origin. Southern zone showed high values in aroma and hue, Central zone had high viscosity values while Coastal zone had highest V values in clarity and whiteness compared to other zones. In sample from Acacia origin. Northern zone had significantly (p < 0.05) highest scores in aroma, viscosity and whiteness where Lake zone had high values in clarity and Central zone had high values in hue. Therefore, the study has revealed that fructose was the most abundant sugar in the honey samples while potassium and iron arc the most abundant macro and micro minerals in honey samples under the study. Furthermore, geographical zones and floral origins have significant influences on physical chemicals properties, total phenols and antioxidant activities sugar, minerals and sensory properties of honey samples from five geographical zones and two floral origins in Tanzania. It is therefore recommended that, honey be included in human diet due to its high nutritional and antioxidant properties. In addition, further research be undertaken to create a data base which will successfully enable characterization of Tanzania honey, thus increasing its competitiveness in the local and international market.view
Development and sensory evaluation of yoghurt flavoured with solar dried fruits
(Pearl Research Journals, 2017) Ndabikunze, B. K.; Mumba, F. G.; Ngowi, H.; Chove, L; Mongi, R; Abdulsud, I.
A study of developing solar dried fruit (5%) flavoured yoghurts using three types of fruits was conducted to determine acceptability and shelf life of developed products. A total of six samples namely banana, mango, pineapple, banana/mango, banana/pineapple and mango/pineapple were used as flavours in yoghurts. They were added either as fruit pieces or as powders. Shelf life projection study suggested that developed yoghurt products could be stored for up to 21 days at 4 °C without undergoing spoilage. Plain yoghourt (control) was the most liked sample and scored highest mean values for all attributes, which was significantly different from all other samples (p<0.05). Among the fruit flavoured yoghourts, mango was the most preferred sample in terms of flavor, aroma and general acceptability whereas the pineapple was the least acceptable. Although yoghurts flavoured with fruits pieces scored higher mean values in all sensory attributes than yoghurts flavoured with powdered fruits, no significant differences (p>0.05) between the two forms of fruit flavours was found. This needs to be further investigated. Thus, although the control was the most liked sample, solar dried fruit can be successfully used as yoghurt flavour, which may improve the texture and nutritional quality of the formulated yoghurts, making them available throughout the year, hence increasing farmer’s income.
Monitoring proteolysis in milk caused by pseudomonas fluorescens by the TNBS method
(Pearl Research Journals, 2017-11) Chove, L. M; Grandison, A.; Lewis, M.
The objective of this study was to monitor proteolysis of milk during storage at 20 and 4° C by two strains of Pseudomonas fluorescens namely: NCIMB 702085 (416) and NCIMB 701274 (414) by the TNBS method. Since commercial Pseudomonas fluorescens enzymes are not available, live Pseudomonas fluorescens microorganisms were inoculated into milk followed by extraction and purification by dialysis. Bacterial enzymes obtained were then inoculated into UHT skim milk. Non-inoculated milk was used as a control. Results obtained showed that Pseudomonas fluorescens NCIMB 702085 was more proteolytic than Pseudomonas fluorescens NCIMB 701274. It was concluded that the TNBS method proved useful in monitoring proteolysis in milk by Pseudomonas fluorescens.
Preliminary study on the role of ionic calcium in gelation and proteolysis of UHT milk
(Macrothink Institute, 2017-12-28) Chove, Lucy Mlipano; Lewis, Michael
A study was conducted to determine the influence of ionic calcium on gelation and proteolysis in milk. Raw milk was heated to 142 °C for 2s followed by cooling to 5 °C to make UHT milk. Two sequestering agents, Trisodium citrate (TSC) and Sodium hexametaphosphate (SHMP) were added at 0.04 - 0.08% (w/v) to the processed UHT milk to reduce the ionic calcium levels. Proteolysis and gelation were induced by addition of trypsin (248 BAEE units), 0.03% (v/v) chymosin and 10 6 cfu/mL Pseudomonas fluorescens NCIMB 702085 (Ps. fl. 416) to UHT milk. Samples were stored at 25 °C for 21⁄2 weeks to monitor gelation and Ca 2+ and some were incubated at 37 °C for 2h to monitor proteolysis. SHMP reduced more Ca 2+ than TSC. Ca 2+ reduction was accompanied by an increase in pH, most evident with TSC at 25 °C. Gelation was not observed in samples inoculated with Ps. fl. 416 (with sequestering agents) even after 9 days of storage, suggesting the importance of calcium in gelation. Chymosin treated samples gelled on day 0, whereas other samples gelled after 4 days. Trypsin increased Ca 2+ to levels higher than originally present in control UHT skim milk. Although in the current study, proteolysis was higher in samples inoculated with Pseudomonas fluorescens 416, no clear relationship was established between proteolysis and gelation in UHT milk. This observation implies that proteolytic activity is not influenced by Ca 2+ . However, longer time study using sodium azide to prevent bacterial contamination would be required to confirm these findings.
Detection of proteolysis in milk by pseudomonas fluorescens using urea PAGE method
(Macrothink Institute, 2017-12-28) Chove, Lucy Mlipano; Alistair, Grandison; Michael, Lewis
Proteolysis of milk during storage by two strains of Pseudomonas NCIMB 702085 (414) and NCIMB 701274 (416) was investigated using the Urea PAGE method. Pseudomonas fluorescens enzymes were also extracted and purified by dialysis before inoculation into UHT skim milk in an attempt to partially purify the enzyme. Results showed that dialysis removed some peptides and amino acids which would interfere with the assay procedure. The method also confirmed that Pseudomonas fluorescens NCIMB 701274 (416) was more proteolytic than Pseudomonas NCIMB 702085 (414). Thus, Urea PAGE is a useful method for monitoring proteolysis in milk by Pseudomonas fluorescens.
Effect of depth and distance of the borehole from the septic tank on the physico-chemical quality of water
(Macrothink Institute, 2017-12-28) Chove, Lucy Mlipano; Mongi, Richard; Chenge, Lawrence
A study to examine the effect of depth and distance of the boreholes from the septic tank on physico-chemical parameters of the borehole water consumed in Dar Es Salaam, Tanzania was conducted. Samples were collected from 48 boreholes in Ilala, Kinondoni and Temeke districts and subjected to pH, B.O.D (Biological Oxygen Demand), total hardness, copper and lead analyses in relation to safety and quality levels set by WHO and TBS. Analysis by R-statistics indicated that pH and B.O.D significantly (p<0.05) decreased as the depth of borehole increased, whereas total hardness was significantly (p<0.05) higher in very deep boreholes than the other heights. Total hardness and pH were not significantly (p>0.05) affected by distance between septic tank and borehole and the B.O.D levels were significantly higher in the borehole water situated near the septic tank than those which were far. Based on the physico-chemical characteristics of water, 25% of the samples did not comply with WHO and TBS specification limits while 75% complied, most of which had shallow depths and were situated near the septic tank. It may thus be concluded that both the distance and the depth between septic tank and borehole influenced physico-chemical characteristics of water.
Chemical quality of stream and borehole water used by selected communities in Lushoto district, Tanzania
(An International Journal of Basic and Applied Research, 2020) Hadija, A.; Chove, L.
The chemical quality of water in two streams and three boreholes from Sunga and Mbaru wards in Lushoto, Tanzania was investigated. Water was collected at three locations along the stream, including forest areas, populated area with agricultural activities and less populated areas with agricultural activities. Borehole’s water was collected from three boreholes found in each ward and analyzed for pH, hardness, BOD, phosphates, nitrates by standard methods. Nested design was applied. Data obtained was analyzed by R-Software for ANOVA. Means were separated by Tukey‘s honest at p<0.05. Significant differences (p<0.05) in all chemical parameters (pH: 6.92- 7.34; Hardness; 23.88+64.43;Nitrite 1.73 -19.80; Phosphate 0.58-3.90; Ammonia 0.02-0.08; Lead -0.001-0.002) were observed in locations within the streams except arsenic. DDT was not detected. With the exception of phosphate in both streams, all water samples tested met TZS (2016) standards and WHO (2011) guidelines. This implies that stream water is considered unsafe for use since it exceeded the maximum phosphate limit by TZS (2016). All parameters tested in borehole water met the requirements for both standards except pH and ammonia which exceeded the WHO water guideline. It is recommended that the communities be educated on the best practices to keep water sources safe.
Heavy metal contamination in cocoyam crops and soils in countries around the lake Victoria basin (Tanzania, Uganda and Kenya)
(2020) Mongi, R.; Chove, L.
A study to determine heavy metals concentration and their correlation between soil and cocoyam crops grown at different wetland locations in Tanzania, Kenya and Uganda around Lake Victoria basin was done. A total of 48 cocoyams and 48 soil samples (taken at 0-15 cm deep) were collected in triplicate from various locations in three districts in each country. They were analysed for Mercury (Hg), Arsenic (As), Lead (Pb), Chromium (Cr) and Copper (Cu) concentrations using atomic absorption spectrophotometry (AAS). The mean heavy metals concentration in cocoyam samples were above maximum permissible limits of 0.1 mg/kg for Hg, As and Pb and 5 mg/kg for Cu established by FAO/WHO (1995) and EU (2004; 2006) rendering them unsafe for human consumption. Heavy metals concentrations in soils were higher than in cocoyam samples in all locations in all countries . As and Cr concentrations however, were below the maximum permissible limits of 20 and 75 mg/kg respectively, in all countries. Heavy metals variation occurred both within and among countries, with Kampala, Uganda having significantly (p<0.05) higher values than other locations and countries, respectively. With exception of Pb in Uganda, insignificant correlation (p>0.05) between soil and the corresponding cocoyam crops grown was observed for other metals. Soil and cocoyam crops grown in the selected locations along the wetlands of Lake Victoria basin are contaminated with heavy metals and thus pose health risk to the consumers
Compliance by SMEs to existing Tanzania standards with respect escherichia coli and staphylococcus aureus in cultured milk: a case of Dar es salaam, Tanzania
(An International Journal of Basic and Applied Research, 2021) Samwel, J.; Chove, L. M.
Small and medium enterprises are important for economic growth not only in Tanzania but all over the world. Most of them are informal, without official registration. However, they provide tremendous contribution to food security, nutrition, income generation and poverty reduction in the country. Therefore, upgrading and modernization of Small and Medium Enterprises (SMEs) to ensure food security, safety and quality of food has becomes one of the priorities of Tanzania development visions of 2025, which is the blueprint of structural economic transformation of the country. To help achieve this, the present study was conducted to assess the safety of cultured milk. A total of 33 cultured milk samples were collected from 11 SMEs which were analyzed in triplicate to make 99. Two microorganisms, Escherichia coli and Staphylococcus aureus were analysed in cultured milk. Results were compared against the existing Tanzania standards. The isolates had an overall mean of 2.02 × 102 ± 1.73 × 102CFU/g, 1.91×102 ± 1.85 ×102CFU/g respectively for E. coli and S. aureusc count. The results obtained were higher than the limits set by the Tanzanian Standard (TZS1625:2013). It may thus be concluded that sampled cultured milk was of poor microbial quality and hence not safe for consumption. Poor hygienic practices during milk handling pose a high risk to cultured milk and render it unsafe for human consumption.
Acceptability of soup powders made from selected traditional leafy vegetables grown in Lindi, Tanzania
(2021) Abdallah, A.; Chove, L. M.
A study was conducted to assess the acceptability of soup formulated from traditional leafy vegetables (TLVs) grown in Lindi, Tanzania. Three TLVs, Amaranth hybrids known as amaranthus leaves (AML), Manihortesculenta known as cassava leaves (CAL) and Ipomeabatatas known as sweet potatoes leaves (SPL) which had been optimized for Iron content, were used to prepare 4 vegetable soup formulations (F1– 60.0:7.5:22.5); (F2 –70.0:5.0:15.0); (F3 –80.0:2.5:7.5) and (F4 –40.0:10.0:40.0) respectively. Descriptive sensory analysis was performed by10 trained panelists who used 5 descriptors to quantitatively describe the sensory characteristics of four soup formulations. Thirty consumers assessed the degree of liking of products’ sensory attributes using a 7-point hedonic scale. External preference mapping was performed by relating sensory data with hedonic responses. Mean intensity ratings of descriptive attributes of the soup showed that F1, F2 and F3had significantly higher(p<0.05) mean intensity scores in colour, aroma, and mouth feel than F4. The consumer study showed that, with exception of mouth feel, consumers showed significant differences (p<0.05) between samples in colour, aroma, taste and overall acceptability. It was thus concluded thatF1 was the most liked by consumers due to colour, aroma and mouth feel followed by F2 and then F3 and finally F4. Furthermore, the preference mapping results showed that colour, aroma and mouth feel attributes were the main drivers for positive consumer preference for vegetable soup. Thus, selection and processing of vegetables, which retain these attributes, is of greater importance for consumer acceptability and hence increased utilization for consumer’s health and well-being.
Examination of seasonal variability of indicator polychlorinated biphenyls in nile perch products from lake Victoria, Tanzania
(TAJAS, 2021) Wenaty, A; Chove, B
In the current study, Nile perch products were analysed for seasonal variations in the levels of indicator polychlorinated biphenyls (PCBs). Samples of fish products were collected from Lake Victoria during the dry and rainy seasons and extracted using a common method referred to as QuEChERS (quick, easy, cheap, effective, rugged and safe) methodology. The residues of PCBs in fish samples were detected and quantified by using a Gas Chromatography equipped with Electron Capture Detectors and a Gas Chromatography equipped with Mass Spectrometer (GC-ECD/GC- MS). The concentrations of indicator PCBs in fish samples were generally greater during the rainy seasons than the dry seasons suggesting that seasonality has significant impacts on PCBs contamination in fish. However, the total PCBs in fish in the current study for both seasons were lower than the Maximum Recommended Limits of 75μg/kg that is set by the European Commission for fish and other fishery products. This indicates that the Nile perch products from Lake Victoria are safe for human consumption based on the studied toxicants
Influence of bio-rock P fertilizer on nutritional composition of whole maize grains: the case of Madaba and Morogoro, Tanzania
(An International Journal of Basic and Applied Research, 2022) Chove, B; Tindwa, H; Pela, S
This study was designed to understand the influence of Bio-rock P fertilizer as the source of phosphorous on nutritional composition in maize grain. Bio-rock P fertilizer is a preparation made of rock phosphate and phosphate solubilizing bacteria (PSB). The experiment was laid out in randomized complete block design with three replications each receiving five rates of bio-rock phosphate fertilizer (Control, 20 kg P/ha with PSB, 40 kg P/ha with PSB, 60 kg P/ha with PSB and 80 kg P/ha with PSB). The study was carried out at two geographically different sites; Magadu in Morogoro and Madaba in Ruvuma for the duration of 90 days in the 2019 - 2021 cropping season. In both sites, the results showed that, bio-rock phosphate fertilizer rates had no significant influence on percentage protein, carbohydrate, fibre and moisture content. However, Bio-rock P rates had a significant effect on ash and fat contents of maize grains (p<0.05). Bio-rock phosphate fertilizer rates had no significant influence on percentage protein, carbohydrate, fibre and moisture content. For mineral content, there was significant difference in P, K, Mg, and Fe in Magadu and Madaba samples. Therefore, application of bio-rock phosphate increased macronutrients content (ash and fat) and some of micronutrients specifically phosphorous, potassium, magnesium and iron content and as the rates of bio-rock phosphate increased.

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