Browsing by Author "Ogutu, Collins Ooko"

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    Effects of preparation and Cooking Treatments on Ascorbates and Folate Contents in Selected Vegetables from Marikiti Market , Nairobi county, Kenya
    (Kenyatta University, 2024-07) Ogutu, Collins Ooko
    There has been increased interest and consumption ofAt"ricfm indigenous vcgc('ablcs due {0 their high nutrient content. Food preparation and cooking treatments are |mPortanl determinants of the nutrient composition of African indigenous vegc!ables.. Different food treatment procedures applied to African indigenous vegetables have varied effects on the level and chemical form of the nutrients present in the vegetables. The high levels of micronutrient deficiencies and increased spending on interventions require a foodbased approach. This study investigated the effects of preparation and cooking treatments on ascorbate and folate levels in Affican indigenous vegetables from Marikiti market, Nairobi City. The main goal of the study was determining the best preparation and cooking treatment methods with the highest retention of ascorbate and folate in the African indigenous vegetables. The study design used was experimental design. The independent variables were preparation and cooking treatments while the dependent variables were ascorbate and folate levels in the samples. The African indigenous vegetables used were pumpkin leaves (Cucurbita maxima), spider plant (Gynandropsis gynandra), amaranth leaves (Amaranthus gangeticus) and black African nightshade (Solanum scabrum). The vegetable samples were purchased from Marikiti market, transported to Kenyatta University Food Chemistry Laboratory in portable coolers and stored at 4°C for not more than five days. The preparation procedures conducted were cutting and blanching while cooking treatments were microwaving, boiling and sautéing. The analysis of ascorbate and folate levels in the samples was conducted using high pressure liquid chromatography. Triplicate nutrient analysis was carried out using analytical grade reagents and data analyzed using SPSS and Excel. Analysis of variance was used to determine if there was any significant difference between the nutrient values of the untreated and treated samples. Spider plant leaves had the highest ascorbate and folate levels 102.41 £ 9.99 pg/100g edible portion and 66.94+3.07 ug/100g edible portion respzctively. There was no significant difference between the native levels of ascorbate and the levels after cutting followed by blanching treatment. The retention rates for the cut then blanched spider plant, pumpkin, amaranth and African nightshade leaves were 56.67%, 53.35%, 56.36% and 45.66%. Conversely, folate levels were significantly reduced by cutting followed by blanching. Microwaving, boiling and sautéing also caused significant ascorbate and folate losses in the vegetables. Cutting of vegetables followed by blanching resulted in the lowest nutrient losses followed by microwaving and boiling. Sautéing was responsible for the highest nutrient losses across the treated samples probably due to the high cooking temperature used. Therefore, cutting followed by blanching or microwaving were found to be the most folate and ascorbate conserving procedures for preparing and cooking African indigenous vegetables. Boiling and sautéing caused the greatest nutrient depletion. Hence the best preparation procedure for African indigenous vegetables for maximal retention of nutrients is blanching. Micr_owaving is the most ideal method for cooking African indigenous vegetables that require more heating to make them palatable. This research is beneficial for the food processing industries to help preserve nutrients for processed African indigenous vegetables and the public for nutrient preservation during cooking.