Browsing by Author "Muruke, Masoud H."
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Item Assessment of Antioxidant Properties of Honeys from Tanzania(www.iiste.org, 2014) Muruke, Masoud H.In this study, levels and properties of antioxidants, antiradical and iron chelating activities of honeybee and stingless bee honeys were determined using standard methods. The relationship between honey colour and the studied antioxidants was also explored. Phenolic content of stingless bees honey samples (mean value 847.6 mgGAE/100g) was significantly higher (P<0.0001) than that of raw (412.6 mgGAE/100g) and processed (218.4 mgGAE/100g) honeybee honey samples, respectively. Mean value of flavonoid content was 84.96 mgRE/100g for stingless bee honeys, 44.82 mgRE/100g for processed honeybee honeys and 41.60 mgRE/100g for raw honeybee honeys. β-Carotene and lycopene content varied among the three honey categories studied. Honey from stingless bees exhibited higher levels of the two antioxidants than honey bee honeys. Vitamin C content ranged from 20.4 – 66.7 mg/100g in processed honey, 42.5 – 61.6 mg/100g in raw honeybees honey and from 56.2 – 67.6 mg/100g in stingless bee honeys. The number of antiradical activity units in 1 mg of honey (EAU515) varied significantly between the honey categories (P<0.0001). The mean values were 5.21 mg/100g for processed honeybee honeys, 6.8 mg/100g for raw honeybee honeys and 10.6 mg/100g for stingless bee honeys. DPPH radical scavenging and iron chelating activities were highest (lowest EC50) in stingless bee honeys compared to honeybee honeys. EC50 mean value for DPPH was lowest (4.19 mg/ml) in stingless bee honeys, 12.93 mg/ml for raw honeybees honey and 18.03 for processed honeybees’ honey. Similarly, iron chelating activity was highest in stingless bee honeys (EC50 0.04 mg/ml) followed by raw honeybee honeys (EC50 0.057 mg/ml) and processes honeybee honeys (EC50 0.158). A diversity of honey colours ranging from light coloured to dark honeys was recorded in the samples studied. Majority of honeybee honey colours were described as white and light amber, while all the stingless bee honeys were between light amber and amber colours. There were strong positive correlations among the antioxidants studied (r ≥ 0.5 at P<0.01). Honey colour intensity was found to correlate positively with all antioxidants studied. Consistently darker honeys were found to contain higher levels of antioxidants than lighter honeys. In overall, Tanzanian honeys studied contains high levels of antioxidants, depicting good quality characteristics for use as food and as medicine.Item Assessment of Quality of Tanzanian Honey based on Physicochemical Properties(www.iiste.org, 2014) Muruke, Masoud H.Quality of Tanzanian honey based on physicochemical parameters namely water content, sugar content, pH, ash content, hydroxymethyl furfural (HMF) and honey colour was studied using 26 honey samples collected from ten popular honey producing regions. Analyses were carried out in triplicates using standard methods. Data was analysed using averages, correlation and ANOVA tests. Majority of the honeybees’ honey samples were light coloured while all stingless bees honey samples were dark coloured. Dark coloured honeys contained more minerals; mainly iron, copper and manganese which make them especially fit for medicinal purposes. pH values ranged from 2.61±0.12 to 4.37±0.08, stingless bees honey samples were more acidic than honeybees’ honey samples. Total sugar content values (64.16-84.84 g/100g) were all above the minimum requirement of the national and international standards of not less than 60g/100g. HMF values ranged from 5.0 – 26.4 mg/kg honey, an indication of good quality, being far below the maximum limit allowed by national and international standards of 40mg/kg or 80mg/kg for honeys from the tropics. Of the 26 honey samples studied, all 5 honey samples from stingless bees and 3 from honeybees had moisture content levels above 21%, the maximum limit allowed by national and international standards.. With the exception of two samples from stingless bees, all honeybees honey samples met the minimum requirements of national and international quality standards of maximum allowable ash content of 0.6 %. ANOVA results showed significant differences in the studied physicochemical parameters between groups of honey samples, namely processed honey raw honey and stingless bees’ honey at P<0.05. Pearson correlation analysis showed strong correlation coefficients at P<0.05 between some parameters studied. In conclusion honey colour and moisture content are two important physicochemical parameters that may be used to assess quality of honey.Item Bioactivity of Crude Extracts of Ascomycetes Isolated from Tanzanian Traditionally Fermented Milk, Mtindi(2014-01) Mlimbila, Jane; Muruke, Masoud H.; Hosea, Ken M.In an attempt to find potential functional foods in Tanzania, a study was conducted to assess bioactivity of 18 ethyl acetate extracts from nine (9) Ascomycetes strains. Namely; Candida tropicalis, C. pararugosa, Clavispora lusitaniae, Issatchenkia orientalis, Pichia kudriavzevii, Pichia guilliermondii, Galactomyces geotricum, Debaryomyces hansenii and Yarrowia lipolytica isolated from traditional fermented milk “mtindi”. Lethality test of the extracts was determined using Artemia salina naupalii in a Brine Shrimp Test (BST). The lethal concentration (LC50) obtained ranged from 89.7µg/ml to over 1000 µg/ml. Bioactivity results showed that, one of the 18 extracts had exhibited a strong antibacterial activity against Staphylococcus aureus, Pseudomonas aureginosa and Vibrio cholera having minimum inhibitory concentration (MIC) values of 0.1653mg/ml on each account. More than 40% of extracts exhibited strong to moderate antifungal activity against Cryptococcus neoformans (MIC 0.16 mg/ml – 1.25 mg/ml). In conclusion, these results suggest that yeasts found in traditional fermented milk have potential biological activity that could be used for treatment of some diarrhoeal and fungal infections and possibly tuberculosis.Item Isolation and Identification of Local Ethanolic Yeasts Inhabiting Coffee Processing Environments in Tanzania(2014-12-20) Hamadi, Said; Muruke, Masoud H.; Hosea, Ken M.M.Coffee processing environment harbours different microbiota of fungi and bacteria, some of which are of great economic value. This study isolated, screened and identified indigenous yeast associated with ethanol production potential in coffee processing environments of Mbinga in Ruvuma region and Hai in Kilimanjaro region using standard procedures. Yeast identification was done by amplification and sequencing D1/D2 domain of the gene 26S rDNA. A total of 21 yeast isolates were obtained from both sites and only 8 of them were able to ferment glucose. All 9 isolates fermented coffee pulp waste to ethanol at varying levels. Highest ethanol production was observed by isolate M4, which produced 3% (v/v) ethanol, followed by PDA4MB (2.8% v/v), PDA3 (2.6% v/v) and the least was by M2 which produced only 1.1% (v/v).Three isolates showed good attribute to ethanol production (2.76 to 3.56% v/v) even after an addition of higher sugar concentrations to coffee pulp waste. The basic local alignment search tool (BLAST) and phylogenetic analysis revealed the identity of the yeasts as Pichia kudriavzevii, Issatchenkia orientalis, Clavispora lusitaniae, Pichia guilliermondii, and Pichia anomala, all of them known to be associated with ethanol fermentation. Their attributes towards ethanol fermentation are taken to be potential for further investigation for bioethanol production.Item Molecular Identification and Proteinase Activity of Yeasts Isolated from Fermented Milk(2013) Mlimbila, Jane; Hosea, Ken M.; Muruke, Masoud H.The aim of this study was to identify yeasts from traditional Tanzanian fermented milk, “mtindi” and industrial fermented milk, “yoghurt” and to determine their in vitro proteolytic activities. A total of twenty five yeast isolates were studied. Identification was done by ribosomal DNA - Polymerase Chain Reaction (PCR) amplification and sequencing of the domains D1/D2 of the 26S rRNA gene. The identified yeasts were Candida tropicalis, C. pararugosa, Clavispora lusitaniae, Issatchenkia orientalis/Pichia kudriavzevii, Pichia guilliermondii/Meyerozyma guilliermondii, Galactomyces geotricum, Debaryomyces sp and Yarrowia lipolytica. However, Y. lipolytica and D. hansenii were detected from yoghurt samples only, while G. geotrichum was found in both mtindi and yoghurt samples. Candida sp. and Pichia sp. were detected in mtindi samples only. The highest yeast load was of C. paragurosa (over log 6 CFU/ml) and P. guilliermondii was the least isolated strain in numbers of slightly over log 2CFU/ml (p<0001). Proteolytic activity was analysed by plate assay using nutrient agar media supplemented with milk casein. Over 80% of the isolates were protease positive. The highest activity was detected on C. pararugosa isolated from mtindi with the diameter of clear zone 36.667+5.4mm, (p<0.01). Our results showed the potential of dairy yeasts as a source for further exploitation of the production of proteolytic substances with either potential health benefits or spoilage abilities.Item Optimization of Fermentation Parameters for Production of Ethanol from Coffee Pulp Waste Using Pichia anomala M4 Yeast Isolated from Coffee Environment in Tanzania(2014-11-10) Hamadi, Said; Muruke, Masoud H.; Hosea, Ken M.M.Abstract Coffee pulp waste (CPW), an abundant agro-waste available in Tanzania was studied as a potential substrate for bioethanol production. Selected yeast Pichia anomala M4 previously isolated from coffee environment was tested against three fermentation parameters namely pH, temperature and soy flour supplementation. Maximum ethanol of 4.7% (v/v) and 4.07% was produced at an optimum pH 4.5 and temperature of 30 0C respectively. There was a significant increase (ANOVA, P˂0.05) in ethanol production on addition of soy flour as a supplement with a maximum yield of 6.04% (v/v) ethanol at a soy flour concentration of 2.0% g/l. A slight increase on ethanol production (6.3% v/v) was recorded when all the three parameters were put together. Appreciable amount of sugar content (8.2 g/l) found in CWP and significant levels of ethanol produced by yeast from the agricultural waste, calls for more research on how best to utilize this untapped bioresource.