Browsing by Author "Chove, B. E."
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Item Comparative evaluation of different methods of extraction and purification used in technical enzyme production from microorganisms(Tanzania J. Agric. Sc, 1998) Gidamis, A. B.; Nnko, A.; Shayo, N. B.; Chove, B. E.; Kroner, H. K.A stlldy was conducted to compare the efficiency of two methods of microbial cell separation and enzyme purification using penicillin-G-acylase (PGA) from Escherichia coli. The efficiency of two methods of ceJ[ separation; centrifugation and cross flow filtration (CFF) were compared. The CFF method was found to have both higher separation efficiency and enzyme yield than centrifugation method. Centrifugation method gave a separation efficiency of 98.5% with enzyme yield of94 % whereas CFFmethod resulted in 100% separation efficiency and enzyme yield of98.8%. The Escherichia coli cells were disrupted by high pressure homogenization (HPH),and the disrupted cells were purified using two different techniques. Technique I was a combination of cross-flow-diafiltration (CFD) , ultrafiltration (UF) and heat/pH-shift treatments. This technique resulted in 47% enzyme yield with a purification factor of 12. Technique II which involved two extraction steps by' aqueous two - phase system (APS) coupled with UF resulted in 62 % enzyme yield with a pu;ificationfactor of 4. Technique I was therefore much better than techriique Il in purifying the enzyme. For higher enzyme yield, technique II would seem to be a better one than technique I.Item Copper and Lead levels in two popular leafy vegetables grown around Morogoro Municipality, Tanzania(Tanzania Health Research, 2006) Chove, B. E.; Ballegu, W. R.; Chove, L. M.A study was carried out to determine the levels of two heavy metals, Lead (Pb) and Copper (Cu), in two popular leafy vegetables grown around Morogoro Municipality in Tanzania. Vegetable samples of Pumpkin leaves (Cucurbita moschata) and Chinese cabbage (Brassica chinensis) were collected from three sites and analysed for their concentrations of the two metals using an Atomic Absorption Spectrophotometer. The three sites, namely Mazimbu, Kihonda and Towelo are located within a 10 km perimeter. The site selection was based on the anticipated levels of contamination of the water used for irrigation. The results showed that the levels (mg/100g dry weight) ranged from 0.885 to1.39 for Copper and 0.05 to 0.315 for Lead. The levels of Lead and Copper varied between the vegetable varieties and from site to site. Vegetables from Mazimbu showed higher concentration levels of the two metals compared to the other sites in both varieties. Towelo vegetables had relatively low concentrations. There was a significant difference (P<0.05) in levels of the two metals across the sites but there was no significant difference (P>0.05) in the levels of Copper between the two vegetable varieties from all the three sites. There was a significant difference (P<0.05) in the levels of Lead between the vegetable varieties. The levels of both Lead and Copper in the two vegetables were found to be below the maximum permissible levels recommended by FAO/WHO for the two metals in vegetables.Item Effect of germination and autoclaving of sprouted finger millet and kidney beans on cyanide content(Tanzania Journal of Health Research, 2010) Chove, B. E.; Mamiro, P. R. S.Cyanide contents of locally purchased brown finger millet (Eleusine corocana L. Gaertner) and brown speckled kidney bean seeds (Phaseolus vulgaries var. Rose Coco) were determined using raw, germinated and autoclaved samples. The aim was to establish the extent of cyanide content increase resulting from the germination process and the effectiveness of the autoclaving process on the reduction of cyanide levels in the samples, for safety considerations. Autoclaving was carried out at 121°C for 20 minutes. It was found that germination increased the cyanide content by 2.11 to 2.14 fold in finger millet for laboratory processed samples. In the case of kidney beans the increment was 1.76 to 1.77 fold for laboratory samples. The increments for field processed samples were in the same range as those for laboratory samples. Autoclaving reduced the cyanide content to between 61.8 and 65.9 % of the original raw contents for finger millet and between 56.6 to 57.8% in the case of kidney beans. The corresponding reductions for field samples were also found to be within the same ranges as the laboratory processed samples. It was concluded that autoclaving significantly reduced the cyanide levels in germinated finger millet and kidney beans.Item Emulsifying properties of soy protein isolates obtained by microfiltration(Society of Chemical Industry, 2002) Chove, B. E.; Grandison, A. S.; Lewis, M. J.Soy protein isolate (SPI) fractions were produced using two different pore size micro®ltra- tion membranes. Micro®ltration was carried out on SPI produced by isoelectric precipitation of a crude protein extract. Five fractions were obtained: two retentates and two permeates from the two membranes plus an intermediate fraction obtained as the retentate on the small-pore-size membrane using the permeate from the larger-pore-size membrane. Emulsions stabilised by the retentate fractions exhibited higher values (P < 0.01) of emulsion stability index (ESI) and emulsifying activity index (EAI) than those stabilised with fractions made from the permeates. The intermediate fraction gave intermediate ESI values, while the EAI values were not signi®cantly different from those for SPI and one of the retentates. SDS-PAGE pro®les indicated that the fractions exhibiting high functionality in terms of ESI and EAI were also richer in 7S globulin soy protein subunitsItem Influence of storage temperature and time on the physicochemical and bioactive properties of roselle-fruit juice blends in plastic bottle(Food Science & Nutrition, 2014) Mgaya-Kilima, B.; Remberg, S. F.; Chove, B. E.; Wicklund, T.Roselle-fruit juice blends were made from roselle extract and mango, papaya, and guava juices at the ratio of 80:20, 60:40, 40:60, and 20:80, % roselle: fruit juice, respectively. The blends were pasteurized at 82.5°C for 20 min and stored in 100 mL plastic bottles at 28 and 4°C for 6 months. The effects of storage time and temperature on physicochemical and bioactive properties were evaluated. Total soluble solids, pH, and reducing sugars increased significantly (P < 0.05) in some blends while titratable acidity decrease with increasing storage time. Vitamin C, total monomeric anthocyanins (TMA), total phenols (TPC), and antioxidant activity (ferric reducing ability of plasma, FRAP) in all roselle-fruit blends (40% roselle) decreased significantly (P < 0.05) at 28 and 4°C as storage progressed. Vitamin C in all roselle-fruit blends (40% roselle) decreased from 58–55% to 43–42% when stored at 28 and 4°C, respectively. TMA losses were 86–65% at 28°C and 75–53% at 4°C while TPC losses were 66–58% at 28°C and 51–22% at 4°C. Loss of antioxidant capacity (FRAP) was 18–46% at 28°C and 17–35% at 4°C. A principal component analysis (PCA) differentiated roselle- juice fruit blends into two clusters with two principle components PC1 and PC2, which explained 97 and 3% (blends stored at ambient temperature) and 96 and 4% (blends stored at refrigerated temperature) of the variation, respectively. PC1 differentiated roselle-guava juice blends which were characterized by vitamin C, TPC, FRAP, and pH, while PC2 from another cluster of roselle-mango and roselle-papaya juice blends and was characterized by TSS, RS, and color parameters (L* a* b*). However, TMA was the main variable with the highest effect on all roselle-fruit juice blends regardless of the storage time and temperature.Item Physio-chemical, mineral composition and antioxidant properties of roselle (hibiscus sabdariffa l.) Extract blended with tropical fruit juice(Ajfand, 2014) Mgaya, K. B.; Remberg, S. F.; Chove, B. E.; Wicklund, T.Different varieties of fruit juices and beverages are available globally and there has been an increased consumption of fruit juices and beverages due to consumer awareness of nutritional and health benefits. Juice extracts are produced from various parts of plants including leaves, fruits and flowers. Hibiscus sabdiriffa (Roselle) is one such plant whose flowers are used to prepare juices. The roselle extract has a unique red colour, good flavour, low sugar and high acidic content. The acidity makes the juice sour hence the need for addition of sweetening products. A study was conducted on the formulation of roselle extract-tropical fruit blends aimed at establishing its physiochemical, mineral and antioxidant composition. Dried roselle calyces at a ratio of 1:10 (dried roselle calyces: water) were extracted at 50oC for 30 minutes. The roselle extracts were blended at various proportions of fruit (mango, papaya and guava) juices. Physiochemical, mineral composition and antioxidant properties were evaluated in all the roselle fruit juice blends The results for all rosellefruit blends (80% roselle to 20% roselle) showed that pH ranged between (2.35-3.32), total soluble solids (5.6-10.6o Brix), titratable acidity (1.28-1.92 %), reducing sugars (2.95-5.55) mg/100g,. Calcium (555.3-23.4 mg/100g DM), Magnesium (213.8-11.5 mg/100g DM), Phosphorus (39.8-9.0 mg/100g DM), Sodium (2.3-5.47 mg/100g DM), Zinc (5.85-0.69 mg/100g DM), Iron (29.5-1.36 mg/100g DM), monomeric anthocyanin (493.5-118.2 mg cyanidin-3-glucoside/100g), vitamin C (40.0-86.5 mg/100g), total phenol (54.6-10.8 mg gallic acid/ 100 g) and antioxidant activity (1.80-1.37 mmol/L). Blending of tropical fruit juices with roselle extract have improved mineral composition and antioxidant properties of fruit juices as roselle is a good source of calcium, magnesium and iron. Antioxidants acts as free radical scavengers inhibit lipid peroxidation and other free radical mediated process, therefore, consumption of roselle-fruit juices with high anthocyanin will protect human body from several diseases attributed to the reactions of free radicals.Item Proximate composition, bread characteristics and sensory evaluation of Cocoyam-Wheat composite breads(Ajfand, 2011) Mongi, R. J.; Ndabikunze, B. K.; Chove, B. E.; Mamiro, P.; Ruhembe, C. C.; Ntwenya, J. G.This study was carried out to investigate proximate composition, bread characteristics and sensory evaluation of cocoyam-wheat composite breads at different levels of cocoyam flour substitution for human consumption.A whole wheat bread (WWB) and cocoyam-composite breads (CCB1,CCB 2 and CCB 3) were prepared in triplicate at 0, 10, 20 and 30% levels of cocoyam flours substitution respectively and assessed for proximatecomposition, bread characteristics and sensory attributes.The results indicate that carbohydrate, crude fiber, and ash contents of the cocoyam-composite breads increased significantly (p<0.05) while the moisture and protein contents decreased significantly with progressive increase in the cocoyam flour substitution. The significant (p<0.05) highest ash, fibre and carbohydrate values of 1.61, 1.54 and 70.40 g/100g dm respectively were observed in 30% cocoyam-wheat composite bread compared to lowest values of1.15, 0.29 and 63.25 g/100g dm, respectively in 100% wheat bread. The significant (p<0.05) higher moisture and protein values of 20.99 and 12.54 g/100g dm were observed in 100% wheat bread compared to lowest values of 17.31 and 9.04 g/100g dm, respectively in 30% cocoyam-wheat composite bread. Bread characteristics showed that, the loaf weight of cocoyam composite breads increased significantly (p<0.05) while loaf volume and specific loaf volume decreased significantly (p<0.05) with increasing cocoyam flour substitution The significant (p<0.05) highest loaf weight of 229.33 g was observed in 30% cocoyam-wheat composite bread compared to 208.33, 221.67 and 225 g observed in 100% wheat bread, 10 and 20% cocoyam-wheat composite breads respectively. The highest loaf volume and specific loaf volume of 800 and 3.49 cc were observed in 100% wheat bread compared lowest values of 580 and 2.78 cc respectively observed in 30% cocoyam-wheat composite bread. The sensory evaluation showed no significant (p>0.05) differences in sensory attributes of taste, aroma and acceptability between the 100% wheat and 10% cocoyam-wheat composite breads (p<0.05). In conclusion, this study has shown that the use of cocoyam flour in bread making is feasible and that incorporation of up to 10% of the flour into wheat flour produced acceptable bread with similar taste and aroma comparable to 100% wheat bread. Nevertheless, it is important to consume this bread with other protein rich diet in order to supplement the reduction resulted from substitution.Item The quality of water in small community supplies of Kingolwira village, Morogoro, Tanzania(Tanzania Health Research, 2007) Shayo, N. B.; Chove, B. E.; Gidamis, A. B.; Ngoma, O. B.Water quality is an important aspect in human health, as the majority of infectious diseases that cause morbidity and mortality in population are water related. The present study was undertaken to assess the quality of water in Kingolwira, Morogoro Rural District, Tanzania. Water was collected from different sites in the village and analysed for a period of six months. Physical, chemical and microbiological qualities of water were examined. The pH of the water ranged from 7.02 to 7.20 and the water temperature ranged from 25.70C to 27.00C. The total dissolved solids of the water samples ranged from 110 to 510 ppm. The water contained considerable levels of lead and copper ranging from 0.034 to 0.090 ppm and 0.022 to 0.030 ppm, respectively. Total water hardness ranged from 19.60 to 228.10 ppm as calcium carbonate. The total viable counts and faecal coliform counts ranged from 2.75x103 to 5.4 x 103 c.f.u/ml and 0.93 x102 to 2.1x102 counts/100ml, respectively. Overall, water supplies in the village were judged as of poor quality. Water is usually used for domestic purposes including cooking, drinking, washing and preparation of infant foods without any treatment. In conclusion therefore, water in Kingolwira village is of poor quality and needs to be treated before consumption. Theres is also a need for the rural population to be educated on hazards of using untreated water. In general, sanitary facilities in rural areas in Tanzania need to be improved in order to avoid health hazards.