DSpace Collection:http://41.89.96.81:8080/xmlui/handle/123456789/21742024-03-29T00:37:52Z2024-03-29T00:37:52ZScreening and molecular characterization of microorganisms producing hydrolytic enzymes for cassava (manihot esculenta crantz) starch degradationMuriithi, Josphine Nyamburahttp://41.89.96.81:8080/xmlui/handle/123456789/32212024-01-19T10:26:09Z2023-08-01T00:00:00ZTitle: Screening and molecular characterization of microorganisms producing hydrolytic enzymes for cassava (manihot esculenta crantz) starch degradation
Authors: Muriithi, Josphine Nyambura
Abstract: Corn starch is a traditional source of glucose in the food industry, but its use is limited due to competition with corn as a staple food. Cassava (Manihot esculenta Crantz), which has a high starch content, is a potential alternative starch source. However, the complex structure of cassava starch hinders its industrial application. This study aimed to isolate and identify microorganisms capable of producing amylase enzymes from diverse and unexplored environments in Kenya. The initial screening involved evaluating the ability of microorganisms to grow on minimal media supplemented with starch. Based on this screening, 70 microbial amylolytic isolates were selected. These isolates underwent a primary screening based on starch hydrolysis ratio (SHR), determined by halo formation on starch agar plates after flooding the plates with Lugol's iodine solution. This narrowed down the number of isolates to 17, which were presumed to be excellent amylase producers (SHR > 1.5) and were further used in subsequent experiments. The 17 selected isolates were cultivated in M9 starch broth media at an optimum temperature of 30°C and pH 7.0 to produce amylase enzymes. Crude amylases were extracted from the supernatant, quantified at 280 nm, and assessed for amylase activity using the 3,5-dinitrosalicylic acid (DNSA) method. Enzyme stability was tested through incubation at 30°C for 18 hours, while the effect of temperature and starch loading was evaluated by measuring activity at 45°C, 50°C, and 55°C, and with starch concentrations of 20%, 50%, and 60%, respectively. A commercial amylase was used as a control. The specific enzyme activities of the crude enzymes from the 17 isolates ranged from 0.0079 U g-1 to 0.0629 U g-1, which were lower compared to the specific activity (1.7188 U g-1) of the control enzyme. The top 5 enzymes with the highest specific enzyme activity were selected for cassava hydrolysis. These crude enzymes exhibited higher specific enzyme activity (0.0707–0.1853 U g-1) than the control enzyme (0.0052 U g-1) in hydrolyzing cassava starch. Among the isolates, those with the highest specific enzyme activity were identified through DNA sequencing and belonged to Lysinibacillus spp. (4 isolates), Alternaria spp. (1 isolate), and Bacillus spp. (2 isolates). Alkaline lakes (Lake Elementaita and Lake Bogoria) had the highest number (4) of isolates with enzymes showing the highest specific enzyme activity, followed by the gut contents of black soldier flies. The specific enzyme activity increased with temperature, and starch loading had an impact on enzyme activity. While most enzymes showed reduced activity over time at 30°C, enzymes from one isolate retained full activity at 18 hours of incubation, demonstrating thermostability. This study highlights the presence of microorganisms with amylase activity in tropical environments that can be scaled and optimized for practical applications2023-08-01T00:00:00ZEvaluation of quality properties of protein-rich snack bar developed from pre-gelatinized taro (colocasia esculenta l.) Flour enriched with soybeans (glycine max l.)Oyim, Irene Ragarhttp://41.89.96.81:8080/xmlui/handle/123456789/31962024-01-16T07:25:16Z2023-07-01T00:00:00ZTitle: Evaluation of quality properties of protein-rich snack bar developed from pre-gelatinized taro (colocasia esculenta l.) Flour enriched with soybeans (glycine max l.)
Authors: Oyim, Irene Ragar
Abstract: Food producers make sure to offer quick-to-prepare, nutrient-dense food options that are suited to consumers' tastes and fast-paced lifestyles. Developing such foods is imperative given the need to address malnutrition, more so Protein Energy Malnutrition (PEM). As a result, manufacturers are now focused on investigating innovative strategies like food-to-food fortification, which involves enhancing traditional staple foods with locally accessible, nutrient-dense, and underutilised crops like taro and soybean flour. This study thus aimed at innovatively developing protein-rich snack bars from pre-gelatinized taro flour enriched with soybeans. Producing pre-gelatinized taro flour under varying conditions and assessing its physico-chemical properties was the first step. Second step was to enrich pre-gelatinized taro flour with soybeans (raw, malted, roasted, and malted-roasted) to make flour blends for snack bars. Subsequently, followed by evaluating the microbial safety, nutritional components, sensory attributes, and shelf life through proximate content analysis, in-vitro protein digestibility, descriptive and consumer sensory tests, and accelerated shelf testing using the Arrhenius model. The data obtained was analysed using Statistical Analysis System software and significance tested by performing an analysis of variance (ANOVA) at 5% significance level. .Pre-gelatinization by boiling significantly reduced the oxalate content (56.7%), while roasting resulted in the least reduction (36.2%). Boiling also resulted in flour with the highest bulk density (BD) (0.86g/cm3) and the lowest water solubility index (WSI) (9.39%). Steamed flour had the highest water absorption index (WAI) (3.81 g/g), water holding capacity (WHC) (4.59g/g), and swelling capacity (SC) (4.86 g/g). Enriching pre-gelatinized taro flour with soybeans significantly increased crude protein, lipid, gross energy value, and in vitro protein ddigestibility (IVPD). The crude protein content increased by a proportional range of 55.75-337.76%, crude fat content increased by 189.09% to 949.09%, and the gross energy value ranged from 2.46-13.53%. Total phenolic in the snack bars increased significantly as soybean flour inclusion level increased. The enrichment also significantly affected the sensory attributes of the developed snack bars. Compositing with roasted soy flour resulted in a snack bar with the highest colour intensity and highly perceivable aroma. Compositing with malted and malted-roasted soy flour resulted in less brittle snack bars. The Arrhenius model predicted shelf life showed that snack bars had a shelf life of between 29 and 72 days. The findings show that taro and soybeans have the potential to be used in protein-rich bars to combat malnutrition, like PEM. Utilisation of these ingredients has the potential to improve food security and nutrition in disadvantaged Kenyan communities2023-07-01T00:00:00ZKnowledge of young children caregivers a bout mycotoxins their postharvest handling practices of sorghum and effects of fermentation of aflotoxin and fumonisin levels in sorghum grains and flour in Kerio Valley KenyaLesuuda, Lmeriaihttp://41.89.96.81:8080/xmlui/handle/123456789/30492023-12-13T12:43:11Z2023-04-01T00:00:00ZTitle: Knowledge of young children caregivers a bout mycotoxins their postharvest handling practices of sorghum and effects of fermentation of aflotoxin and fumonisin levels in sorghum grains and flour in Kerio Valley Kenya
Authors: Lesuuda, Lmeriai
Abstract: Undemutrition among children under five years old is still a problem in many developing countries including Kenya. Kerio Valley of Elgeyo Marakwet County is among the regions with high stunting rates in Kenya. Mycotoxin contamination of complementary foods has been suggested to cause undemutrition. Sorghum is one of the basic ingredients used to prepare complementary foods. This study, therefore, aimed to; document children under five years caregivers’ knowledge of aflatoxin and fumonisin contamination in sorghum alongside their postharvest handling and storage practices of sorghum and detennine the effects of fermentation on aflatoxin and fumonisin levels in sorghum grain and flour. A cross-sectional study was conducted to obtain both qualitative and quantitative data from 374 caregivers. Multistage sampling procedmes were used to select study participants. Overall, majority of the caregivers had poor knowledge (61.8%) about mycotoxin contamination and poor postharvest handling and storage practices of sorghum (74.5%). The caregiver's knowledge about mycotoxins was significantly associated with age [(AOR=4.629, p <.00l], education level [(AOR=0.275, p =.OOl], marital status [(AOR=l5.l87, p =.0l2] and household monthly income [(AOR=2.623, p <.00l]. Furthermore, the caregiver‘s age [(AOR=3.845, p =.003], education level [(AOR=O.l96, p <.0Ol)], monthly income [(AOR=3.29l, p =.OO2] and knowledge of mycotoxin contamination of sorghum [AOR, 5.428, p <.00l] were significantly associated with postharvest handling and storage practices. The mean value for total aflatoxin level in sorghum grains (33.85i26.00) and flour (36.72il9.50) were above l0ppb the regulation limits for aflatoxins. Additionally, fiimonisin mean values for the sorghum grains (1 29018.07) and flour (1 00417.21) samples were above the (l ppm) regulation limit. Type of fennentation (natural and use of Lactobacillus Plantarum) (F=24.287, p=0.00l), type of sample (flour or grain) (F=9.706, p=0.004) and fermentation duration (F: 3.690, p=0.037) contributed significantly to the reduction of aflatoxin and fumonisin levels. In conclusion, poor caregivers’ knowledge coupled with suboptimal post-harvest handling and storage practices may have contributed to high aflatoxin and fumonisin recorded in sorghum grains and flour. This increases the risk of mycotoxin exposure to young children, which could be one of the contributing factors to high stunting rates in Kerio valley. This thus necessitates mitigation measures including sensitization campaigns and social behaviour change communication such as the adoption of fermentation by caregivers of children under five years as one of the complementary foods processing techniques2023-04-01T00:00:00ZAssessment of Caregivers’ Nutrition Knowledge, Attitudes and Practices on Diet Adequacy and Nutritional Status of Children 6-23 Months in Rongai Sub-County, KenyaKemboi, Sharon Chepng’enohttp://41.89.96.81:8080/xmlui/handle/123456789/27302021-08-13T07:41:30Z2021-05-01T00:00:00ZTitle: Assessment of Caregivers’ Nutrition Knowledge, Attitudes and Practices on Diet Adequacy and Nutritional Status of Children 6-23 Months in Rongai Sub-County, Kenya
Authors: Kemboi, Sharon Chepng’eno
Abstract: Under nutrition among children is still a global concern affecting many developing
countries. Lack of adequate nutrition knowledge among caregivers translates to inappropriate complementary feeding practices hence under nutrition especially among children aged 6-23 months. Caregivers’ knowledge, attitudes and practices (KAP) on infant and young child nutrition (IYCN) have been associated with child diet adequacy and nutritional status. Varied results and recommendation have been documented from studies done to investigate the association of caregivers’ KAP on IYCN and nutritional outcomes. Therefore, the aim of this study was to assess caregivers’ nutrition KAP regarding IYCN on diet adequacy and nutritional status of children aged 6-23 months in Rongai Sub-county, Nakuru County. A cross-sectional study design was conducted among 388 randomly selected caregiver and child pairs. Sociodemographic and KAP related data were collected using a researcher-administered structured questionnaire. A Qualitative 24-Hour Food Recall data was used to generate child diet diversity. Child anthropometric measurements were taken and z-scores computed. All data were analyzed using Statistical Package for Social Sciences (SPSS) version 20.0. Caregivers had low knowledge on young child feeding (83.3%), dietary diversity (98.2%), and water and
sanitation (92.7%). Moreover, all caregivers (100%) attitudes on young child feeding and
dietary diversity were negative. Overall, 65.6% of caregivers had poor practices on young child feeding and were significantly different (P>0.004) across the two agro-ecological zones. More than half (56.9%) of the children had minimum diet diversity (MDD) with more children from low potential areas attaining minimum meal frequency (MMF) per day compared to those from high potential area. The overall prevalence of wasting, underweight and stunting was 6.2%, 9.2% and 23.4% respectively with no difference (P>0.05) across the agro-ecological zones. Caregivers’ education level positively (P<0.05) associated with MDD in low potential area [AOR= 3.797, 95% C.I; (1.477-9.759)] and with MAD in high potential area [AOR=1.874, 95% C.I; (1.014-3.465)]. In addition, children from high potential areas whose diets met MDD [AOR=0.129, 95% C.I; (0.027±0.609)], MMF [AOR=0.244, 95% C.I; (0.076±0.785)] and MAD [AOR=5.417, 95% C.I; (1.350±21.732)] requirements were less likely to be underweight. In conclusion, caregivers’ KAP on IYCN varied across the agro-ecological zones and contributed to child diet adequacy and subsequently nutrition outcomes of children. There is need for nutrition education and interventions that target improving caregivers’ KAP on IYCN, child diet adequacy in order to improve children’s nutrition outcomes.2021-05-01T00:00:00Z