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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2647

Authors: Helen, W/Michael
Advisors: Dr.Eng. Shimelis Admassu (Asso. Prof.)
Keywords: Finger millet,
Processing methods,
Chemical composition
Copyright: 2010
Date Added: 6-May-2012
Abstract: Abstract In this study the proximate composition and antinutrtional concentration of six finger millet cultivars were studied. Influence of conventional processing methods (hydration, germination and fermentation) and their combinations, and extrusion cooking, on the proximate compositions, physico-chemical and functional properties as well as reduction of antinutrients in three selected finger millet cultivars (Dibatse, Black and Padet) were also investigated. Sensory analysis of gruel and composite biscuit were studied. The mean value of three selected finger millet varieties’(Dibatse, Black and Padet) moisture content were 7.7, 7.82 and 7.84%, crude protein 9.2, 8.1 and 8.9%, and total ash 1.8, 2.7 and 2.5%, respectively. Micronutrient concentration of the seeds showed large variation. Calcium was the most abundant (1404.3 mg/100g) mineral whereas Zn was low (1.9mg/100g). The ranges for phytate and tannins were 340.7 to 1353.5 and 253.2 to 1255.3, respectively. Significant difference (p<0.05) were observed between varieties in their proximate and antinutritional composition. Germination, fermentation and combined processing methods gave rise to decreased bulk density (1.23-0.43g/cm3) while increasing the water absorption capacity (84.5-139.2), oil absorption capacity (71.4- 126.38) and dispersability (64.4-104.6%). Fermentation of finger millet resulted in a decrease of pH after 6h from 6.2 to 4.7 at 48h, however, pH drop is more significant (p<0.05) when fermented of flour took place prior to germination for 48h . Germination (72h), fermentation (24h) and combined processing method (soaking and fermentation) of finger millet seeds increased significantly (p<0.05) in crude protein by 32%, 42% and 19%, respectively for Dibatse cultivar. The total mineral values of processed finger millet cultivars were lower as compared to the unprocessed sample. A significant (p<0.05) variation was noticed in the total amount of calcium, iron and phosphorous within 72h germination. Hydration process was less effective in reducing phytate and tannins as compared with other processing methods due to the less antinutrient loss expected by leaching in cereals. A slight significance was observed during extrusion cooking on elimination of phytate as compared to conventional processing methods. Fermentation (48h) and extrusion (130oC) was found to be the best method for reducing the phytate and tannins content, respectively. However, the most promising result on reduction of antinutreints was observed by germination followed by fermentation. The gruel fortified with 25% of fermented finger millet was more preferred in all sensory attribute investigation, while the gruel prepared from 100% fermented and germinated flour was least preferred. Germinated finger millet flour (30%) can be successfully used as a partial replacement for wheat flour in biscuit making process. Accordingly, gruel fortified by fermented flour and germinated composite biscuit were more acceptable than gruel fortified by germinated flour and fermented composite biscuit. Accordingly, a process technology for the production of snack food from finger millet varieties is suggested.
URI: http://hdl.handle.net/123456789/2647
Appears in:Thesis - Chemical Engineering

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