Process Engineering

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Browsing Process Engineering by Author "Admassu, Shimelis (PhD)"

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    Influence of Baking Time and Temperature on the Quality of Kocho Biscuit Enriched with Faba Bean and Wheat
    (Addis Ababa University, 2010-06) Yohannes, Kalekristos; Admassu, Shimelis (PhD)
    The production of nutritious biscuit from Kocho of low protein and high carbohydrate, mineral and crude fiber; fortified with faba bean of high protein and moderate fat content; and wheat of good glutenin and gliadin; were the bases for enriched biscuit production. The proximate analysis of enriched Kocho biscuit was done using the AOAC, 2003 analytical procedure. The enriched Kocho biscuit showed an upgrade in protein content from 0.96 of whole Kocho biscuit processed at 1700C for 10min to 9.7% of KFWB2 at 1700C for 10min. This also implies that the consumption of 2 pack of 250g each (one pack contain 21 biscuit of each weighing 12g) of enriched Kocho biscuit of blend KFWB2 processed at 1700C for 10min accommodates the daily protein requirement of 39g/day and 50g/day for the age of 1-3 and 4-10; respectively. The mineral content of enriched Kocho biscuit is improved by the presence of Kocho and faba bean. The time and temperature effect of baking the enriched biscuit shows a major change in protein content due to an increase in the faba bean concentration. With increasing temperature and time the value of the protein decreased due to protein denaturation by heat. As can be seen in KFWB3 processed at 1700C when the time increases from 7 to 8, 8 to 9, and 9 to 10min the protein decreases from 9.94%-9.51%, 9.51%-9.08%, and 9.08%-8.99% respectively. Correspondingly, at a fixed time of 10min in KFWB3, an increase in temperature from 1600C to 1700C, and 1700C to 1800C resulted in decrease from 9.56%-9.08%, and 9.08%-8.98% respectively. The result obtained from the SPSS analysis revealed that biscuit KFWB2 processed at 1700C for 10 min. gave best result for protein content of 9.7% on dry basis. This implies that the enriched Koch biscuit is a good source of protein and can support problem solving in protein malnutrition in the country. The farinograph data for various blends of flour revealed that faba bean has 206 FQN which is better than that of wheat of 108FQN. Combination of this faba bean with Kocho flour improves its farinograph quality number from 7 to 200 of KFWF3 and makes it more suitable for biscuit production. The flour property like water and oil adsorption for whole Kocho flour (KF) were 2.29ml/g and 0.93ml/g; respectively which improved to KFWF2 of 2.05 ml/g and 1.15ml/g; respectively which is not significantly different form wheat flour of 2.2ml/g and 1.18ml/g. This makes the enriched Kocho biscuit comparable in terms of farinograph quality number and dough consistency with the standard whole wheat flour biscuit. The water activities of the whole blended flours were in between 0.47% and 0.55% indicating below the minimum water content required by microorganisms. The water activity for the biscuit is also in the range of 3.7% and 6.5%. The moderately high 5 amount of water activity in whole wheat flour biscuit (KFWB5) results in damage by microorganisms. The recommended water activity for the biscuit is in the range of 0.3% and 0.5%.
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    Optimization of Extraction Process Parameters and Characterization of Gin Flavor from Juniper Berries (Juniperus Communis)
    (Addis Ababa University, 2017-06) Tesfaye, Meroda; Admassu, Shimelis (PhD)
    The aim of the thesis work was focused extraction, optimization and characterization of the essential oil from the berries of juniper to Gin flavor. A Juniper Berries of community family was the raw material of the experimental research which was collected from Chilimo forest 70 Km North West (NW) of Adiss Ababa. First, the juniper berries was dried through sun drying. Then the dried juniper berries were crushed in jaw crusher with sieve size and the samples were sieved using a set of sieves sizes arranged. Then after the experimental research activities were carried out by steam distillation set up. A general factorial design was employed to the extraction process using DESIGN EXPERT 7.0 software and linear regression model. This design helped to identify individual effects of extraction time, and particle size, as parameter. In the extraction experiment, the minimum oil yield of 0.487% was obtained at 2 hours and 1.4-2.5 mm and maximum oil yield of 2.27% was obtained 4 hours and 0.355 - 1mm. This shows that, increasing extraction time and decreasing particle size. Increases oil yield, The volatiles juniper berries essential oil in vapour form released from the berries were condensed and characterized their Physico - chemical properties of the berries oil studied for the optimum yield show that the oil is a solidifying oil at room temperature with having yellow colour,1.50 refractive index value, 2.25mpas dynamic viscosity, 170 boiling point, 0.8584g/cm3specificgravity,4.7 pH, 0.5 optical rotation ,1.4 ml/g acid value, 10.23ml/g iodine value, 47.69ml/g saponification value ,0.704% free fatty acid and 71.7 Brix. The chemical composition of essential oil extracted from Juniper berries using steam distillation was identified by GC-MS have α-pinene (73.12%), β‐myrcene (4.29%, β‐pinene (2.15 %), methylene (3.15%), phenylephrine (1.09%), and carene (4.74 %) and Evaluate sensory quality of Dry Gin liquor product. Therefore, particle size and extraction time have greater effect on the quality and quantity of juniper berries essential oil the findings of this study help to indicate the quality of the Juniper Berries oil which is important in the production of high value gin flavor. . Key Words: Juniper berries, Essential oil acceptability, Steam distillation, Extraction process, Gin Flavor.