Food Engineering
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Item Characterization of Heat-Moisture Treared Starch from Locally Produced V. Faba for The Improvement of Freeze-Thaw stability of “Siljo” Paste(Addis Ababa University, 2011-06) Abebe Moges; Shimelis Admassu (PhD)Functional properties of granular and heat moisture treated (HMT) starches isolated from locally grown V. faba CS-20-DK variety were studied for their effect on the freeze-thaw stability of Siljo paste. Faba bean grain was dehulled, milled, sieved and fractionated into, course (>125μm), medium (80-125μm), and fine (< 80μm) size flour particles. Flour fractionates were slurred in a tap water and separated into supernatant and primary starch residue (PSR) using batch centrifuge. Sieving into fine flour particle resulted in higher carbohydrate (79.36%), lower protein, fat, ash, and fiber distribution, and highest starch yield (52.76%) and least nitrogen (0.08%) and ash (0.05%) contents in the total solids of PSR. Starch yield is comparable with 37% yield from horsebean flour obtained by Kawamura et al (1955) method. The starch obtained from fine flour fractionate was subjected into HMT at 19%; 23%; and 27% (d.b) moisture levels, treated in a hot air oven at 1000C for 16hr, and then dried and milled. The effect of temperature on hydration properties and least gellation concentration (LGC) were determined as a measure of water retention capacity of retrograded starch of granular and HMT starch was investigated. Hydrothermal conditioning led to restricted swelling power (SP) and significant increase in water solubility (WS) and water absorption index (WAI) with the level of conditioning moisture. In all investigations highest SP, WS, and WAI of starches in the temperature range of 85-950C suggests that water penetration into the granules can be achieved at elevated temperature. HMT resulted in increase hydrophilic tendency and conversely decreased the hydrophobic tendency. Except HMT19%; LGC of all HMT starches progressively decreased with the increase in conditioning moisture level. Percentage of retrogradation was decreased after HMT. Degree of retrogradation between the 1st and the 4th days starch gels storage was investigated in the range 100-100% (granular); 85-100% (HMT19%); 52-89% (HMT23%); and 48-84% (HMT27%). The effect of partial substitution of HMT starch at various concentrations (9%, 23%, and 38%) on the freeze-thaw stability (% syneresis) of Siljo paste was evaluated. The highest and the least percentage of syneresis were 167% for normal flour and 73% for the 37.5% HMT27% substituted flour. The incorporation of HMT starch resulted in improved resistance of Siljo paste against the re-crystallization process upon cooling. Application of HMT starch is recommended for the production of sauces and soups with a better stability at ambient or refrigerated storage conditionsItem Development and Characterization of Papaya Based Fruit Leather Supplemented with Orange-Fleshed Sweet Potato and Haricoat Bean Flour(Addis Ababa University, 2023-02) Eftu Tesfaye; Solomon Kiros (PhD)The goal of this study was to investigate the production of nutritional fruit leather using haricot bean and orange fleshed sweet potato flours to partially substitute papaya pulp. The study examined β-Carotene content, functional property, anti-nutrient composition, and physicochemical properties, proximate composition of the raw materials and composite pulps, additional to this mineral and microbiological analysis, texture and color analysis, and finally sensory characteristics of the fruit leather were analyzed using standard methods. The formulation for composite flour was developed using a D-optimal mixture design ratio applying Design-Expert®, version 13. Accordingly, 11 composite pulp samples were developed (R1, R2……. R16) and the data analyzed using mini-tab software, the result was evaluated by used one-way analysis of variance (ANOVA) and test of significant (p<0.05).The composite puree samples are significantly different each other at (p<0.05) with increasing haricot bean and orange fleshed sweet potato flour ratios on papaya puree. the optimum fruit leather at run(sample) 11 was made with 60.02% papaya pulp, 19.98% haricot bean, and 20.00% orange-fleshed sweet potato flour showed significantly higher values of β-carotene (746 μg/g), protein (12.05%), fiber (5.32%), and fat (4.09%), and a moisture content (15%) than the control fruit leather(100%papaya pulp),Moreover the texture analysis result of the fruit leather indicated that the hardness, chewiness, and fracturability decreased with the increased amount of haricot bean and orange-fleshed sweet potato flours. The mineral contents of the fruit leathers ranged from Ca 5.37 to 21.49, Mg 11.49 to 22.49, Na 7.88 to 24.20, K 29 to 24.50 mg, Fe 0.13 to 1.72 (mg/100 kg), and Cu, Mn, and Zn were also detected in the zero range In terms of all the sensory parameters except taste and mouth-feel, the optimum fruit leather showed significantly higher scores than the control fruit leather. Generally the results showed that the supplementing of haricot bean and orange fleshed sweet potato flour to papaya puree improved the nutritional quality of the fruit leather.Item Comprehensive Study on Oil Extraction from Papaya (Carica) Seed and Analysis of its Characteristics, Bioactive Components and Antimicrobial Properties(Addis Ababa University, 2024-03) Mekdes Amare; Shimelis Admassu (Prof.)The utilization of whole fruits and vegetables, including the typically discarded parts during food processing, presents an opportunity to reduce agro-industrial waste. This study focused on evaluating the proximate and nutritional potential of Carica papaya seeds and its oil. The oil from papaya seeds was characterized, and the effects of operating parameters (moisture content, temperature and heating time) on oil yield were investigated using a screw expeller. The Box-Behnken design was utilized for the experimental design, and response surface methodology was used to assess the effects and significance of the models on the response variable (oil yield). The maximum extraction efficiency 24.248%. achieved with a moisture content of 6.32 %, heating time of 9.82 minutes, and temperature of 69.54℃. Furthermore, the byproducts obtained from the screw press meal and cake underwent oil recovery through Soxhlet extraction, and the effects of moisture content, particle size, and extraction time were evaluated. Moreover, Physical and chemical properties of the oil also evaluated. Despite the growing interest in papaya seed oil, there is a lack of comprehensive research on its bioactive components and antimicrobial properties. Gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) analysis were employed to identify these components and functional groups for different extraction methods and also Total Phenolic content and Flavonoid content, were determined using standard methods. The results showed an average total Phenolic content of 19.41 ± 1.33 mg GAE/ml of sample and 2.25 ± 0.787 mg QE/g Total Flavonoid content. Antimicrobial properties were assessed using the agar diffusion method, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined through broth dilution methods. The oils exhibited effectiveness against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli. MIC values ranged from 3.125 to 12.5 μl/ml, while MBCs varied from 6.25 to 50 μl/ml.Item Development and Quality Assessment of Nutritionally Enriched Texturized Soya Protein with Ground Flaxseed Flour(Addis Ababa University, 2024-03) Memiru Michael; Kumsa Delessa (PhD)Texturized soya protein is one of the most important meat alternative product among plant proteins. Texturized Soya protein is currently limited to soyabean and cereal in many countries. Whole soyabean and flaxseed were cleaned, milled and defated. The soybean and flaxseed flour were blended using Response(Box-Bhnken) design to formulate composite flour with the ratio of 90%,85%,80% and 10%, 15%,20% respectively where as 120 oc,135oc,140oc, 145oc, 150oc and 60oc, 70oc, 80oc were used for baking and drying respectively. The data generated were statistically analyzed by general linear model analysis of variance using the Minitab software program version 18. Functional properties and proximate analysis were carried out on the flour and texturized Soya protein sample, the result indicated that , fiber,ash ,carbohydrate,moisture value of composite flour increased with the increase in blend proportion (p<0.05) the bulk density,water absorbition capacity,oil absorbition capacity were observed with an increase in flaxseed flour proportion in the composite flour. The mineral content (Fe,Zn,K,Mn,) of texturized Soya protein were improved by the presence of flaxseed flour. Significant difference(p<0.05) in sensory quality of Texturized Soyaprotein with an increase in flaxseed flour was observed. the result of optimization confirmed that texturized soya protein which was dried with drying temperature 60 oc, drying time 24.087 min and blending ratio 20% flaxseed flour with response of moisture content of 8.69,flavor 7.59, overall acceptability 7.64 was selected. it was concluded as the increseang of ground flaxseed flour had increased sensory, proximate,functional properties and mineral content of texturized soya protein.Item Effects of Storage Duration and Temperature on Physicochemical Properties of Goat Meat.(2023-07) Merkebu Sefefe; Kumsa Delessa (PhD)For eons, the production and consumption of meat have been integral parts of our societies. Since it spoils easily, research is constantly being done to find ways to keep it fresher for longer than is currently the case. By analyzing the impact of storage temperature and time on the physicochemical characteristics (pH, tenderness, water holding capacity, and glycogen content) of goat meat, this study advances this effort. The goat meat used in this study was purchased from Queens Super Market in Addis Ababa, and a normal protocol was followed for the physicochemical examination. The physicochemical qualities were analyzed using storage temperatures of -4, 25, 35, and 50°C for a duration of 12 hours. Throughout the course of the storage, samples for the analyses were taken every two hours from the goat meat that was kept at the aforementioned temperatures. The findings of the analysis revealed that there were notable variations (P<0.05) in the samples' physicochemical characteristics over the course of storage. In comparison to other storage temperatures, samples kept at 50 °C for 12 hours showed decreased pH, water holding capacity, and glycogen level. Tenderness increased as the storage temperature rose from -40°C to 50°C, while the water-holding capacity, pH, and glycogen content declined. The protein and fat contents of goat meat stored at a temperature of -4°C and time of 12 h were determined, and the average values were observed to 21.218 and 3.236% for protein and fat respectively. Storage temperature of 25 °C and storage duration of 8 h was selected as optimal condition for storing goat meat. Selection of this optimal condition was done based on the values of water holding capacity, pH, glycogen level and tenderness obtained during the optimization.Item Effects of Roasting Degree on Coffee Quality and Its Compositional Attributes(Addis Ababa University, 2023-10) Amanuel Getachew; Shimeles Shumi (PhD)Coffee is one of the preferable drinkable beverages in the worldwide. However, its palatable acceptability by consumers depends on the degree of roasting quality of the coffee bean regardless of the varaity. The objective of this research was to evaluate the effects of roasting degree on coffee Quality and compositional attributes. Samples of Harar coffee beans whose speciality graded were selected and subjected to 190 to 230°C roasting degree for 5 to 12 minutes using drum roaster. Where the roasting color intensity classified as light(M), Light medium(LM), Medium(M), Medium Dark(MD) and dark degree(DM) of roasts from 190°C - 230°C for 5 to 12 minutes, though the coffee beans have significant changes in physical and chemical properties at different degree of roasting temprature. The result also showed that the volume change and the weight loss by the roasted beans during different types of roasting degree. The roasted coffee beans were grinded and its proximate composition, sensory quality and cupping were evaluated. The result showed that, medium of roasted coffee beans the amount of caffeine, CHO, crude fat, crude fibber, ash content, and moisture content present in harar coffee were evaluated 2.02, 46.2, 14.41, 18.08, 3.31and 2.15 respectively. And the body of coffee at L, LM, M, MD, D roast degree were 6.08, 7.00, 8.58, 8.5 and 6.42 respectively. The roasted coffee beans were evaluated for cup quality at Light, Light medium, medium, medium dark and dark degree of roast by three professional cuppers. Based on cupping evaluation, dark and light roasting degree resulted at the least total cup score for all the coffee roasting degree. Cup quality were evaluated by a team of certified panelists at Great Abyssinia coffee processing and quality analysis laboratory. Effects of roasting temperature and time were significant (P<0.05) on cup quality parameters. The highest values of fragrances, Flavor, Aftertaste, Acidity, Body, Uniformity, Balance, Clean cup, Sweetness and overall acceptability were 8.83, 9.17, 8.83, 8.75, 8.58, 8.25, 8.5, 8.92, 8.33 and 8.83 respectively. According to the cup test result the values of overall quality showed that, all tested samples varied between commercially acceptable and highly acceptable. Highly acceptable values in most cup quality attributes were 87 % to treatments of 210°C for 8 minuteItem A Study on The Flour Properties and Qualities of Wheat-Based Biscuits Supplemented with Faba-Bean and Cassava Flour(Addis Ababa University, 2023-09) Gebremedhn Brhane; Shmeles Shumi (PhD)Faba beans and other legumes are significant due to their high nutritional value. The goal of this study is to investigate on the flour properties and qualities of wheat-based biscuits supplemented with faba-bean and cassava flour. The study examined the proximate composition of both (composite flour and biscuit flour), rheological, and functional properties. Besides mineral content, total energy, gluten content, texture, color attribute, and sensory evaluation have been studied. The formulation for composite flour was developed using a D-optimal mixture design ratio applying Design-Expert®, version 13. Accordingly, 16 composite flour samples were developed (T1, T2……. T16 and control sample) and evaluated using the standard method. The gluten content of wheat flour was significantly different from the whole formulated composite flour and also the samples were significantly different from each other at (p<0.05). The proximate composition shows that the crude protein content of faba-bean flour (23.13±0.00%) is two times more than that of wheat flour (11.75±0.00%) and eight times more than that of cassava flour (2.9±0.02%), respectively. Whereas, composite flours show lower water absorption capacity and higher oil absorption capacity and water solubility than wheat flour. The result showed that the pasting temperature range was 72.55 to 76.70 °C compared with the pasting temperature of the control sample (89.65 °C). Moreover, biscuit developed from 40.5% wheat flour, 40% cassava flour and 19.5% faba-bean flour biscuit looked almost similar to the wheat flour biscuit in all aspect with overall acceptability of 8.05±0.64. In this study the 40.5% wheat flour, 40% cassava flour and 19.5% faba-bean flour biscuit was found to be the most acceptable biscuit and had high crude protein, crude fiber and low gluten content. On the other hand, adding faba-bean flour to wheat-cassava flour positively affects the physical, chemical, color attribute, texture, alkaline water retention capacity, staling rate and sensory characteristics of the biscuits.Item Development of Cellulose Nanocrystal Reinforced Anchote (Coccinia abyssinica) Starch Based Antimicrobial Food Packaging Film(Addis Ababa University, 2023-11) Habtamu Shebabaw (PhD); Anuradha Jabasingh (Assoc. Prof); Shegaw Ahmed (Asst. Prof.)Food packaging is a critical component of the food supply chain, providing protection from contamination, spoilage, and damage. However, the use of synthetic plastics in food packaging has been linked to a number of environmental and health concerns. In recent years, there has been growing interest in the development of sustainable food packaging materials that are biodegradable, compostable, and non-toxic. Anchote starch is a renewable resource that is produced from the roots of the anchote plant. Anchote starch has excellent film-forming properties and can be used to produce biodegradable food packaging films. Cellulose nanocrystals (CNCs) are a promising material for use in sustainable food packaging. CNCs are a natural, biodegradable, and non-toxic material that has excellent mechanical, optical, and antimicrobial properties. Rosemary essential oil is a natural antimicrobial agent that has been shown to inhibit the growth of a variety of bacteria and fungi. The addition of rosemary essential oil to food packaging films can help to improve the antimicrobial properties of the film and protect food from spoilage. The purpose of this study was to develop and characterize CNC reinforced anchote starch-based antimicrobial food packaging film containing rosemary essential oil. Anchote CNC (AnchCNC) was extracted from anchote bagasse (AnchB) by acid hydrolysis method. Anchote starch based antimicrobial nanocomposite (AS/AnchCNC/REO) films incorporated with anchote cellulose nanocrystals (AnchCNC) (1, 3 and 5%) and rosemary essential oil (REO) (2, 4, and 6%) were prepared by the solvent casting method. The chemical components of AnchB and AnchCNC were determined. AnchB, Anchote cellulose (AnchC), and AnchCNC were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and size distribution analysis. The thickness, moisture content, water solubility, water vapor permeability (WVP), mechanical properties and antimicrobial properties of Anchote starch (AS) and AS/AnchCNC/REO films were analyzed. Films containing (3% AnchCNC; 2% REO) and (5% AnchCNC; 2% REO) were chosen based on better tensile strength and their FTIR, thermal, and morphological characteristics were examined. The polyphenol content and antioxidant activity (DPPH inhibition) of films were also determined. The migration of polyphenol from the films to water and ethanol food simulant was studied at 30 °C after 7 days. The release rate and diffusion coefficient of polyphenol migration from the film sample F33 (5% AnchCNC, 6% REO) into water food simulant were determined by overall kinetics and diffusion modeling at 30, 40, 50 and 60 °C. The stability of polyphenol at an ambient storage temperature of 25 °C, as well as the antimicrobial application of the films for meat preservation was evaluated. The chemical treatments (alkali treatment, bleaching, and acid hydrolysis) effectively removed hemicelluloses and lignin from AnchB. The thermal stability of AnchCNC was reduced after acid hydrolysis due to the introduction of sulfate groups. XRD measurements revealed an increase in the crystallinity by 160 % after the chemical treatments. SEM images clearly exhibited an effective removal of the amorphous fractions after the chemical treatments. Zeta sizer analysis showed that AnchCNC had an apparent average diameter of 92 nm and zeta potential value of -21.0 mV. The tensile strength (TS) and WVP of anchote starch films were both dramatically improved by increasing the amount of AnchCNC. A significant reduction in the WVP of films was seen when the amount of REO was increased. The TS property of the films was found to decrease as the concentration of REO was increased. The TS of the AS (control) film was 9.42 MPa. Films containing (3% AnchCNC; 2% REO) and (5% AnchCNC; 2% REO) had shown the highest TS values of 23.41 MPa and 23.44 MPa, respectively. With the addition of 5% AnchCNC and 6% REO, the WVP of anchote starch film was decreased from 8.72 × 10-11 gH2O/Pa.m.s to 3.11 × 10-11 gH2O/Pa.m.s. The antimicrobial films showed satisfactory antimicrobial efficiency against E. coli, Staphylococcus aureus, and Listeria monocytogenes. REO significantly contributed to the antimicrobial efficiency of films. A sample containing the highest percentage (5% AnchCNC and 6% REO) recorded the highest antibacterial efficiency. TGA results showed films containing, 3 % AnchCNC; 2% REO (F21) and 5 % AnchCNC; 2 % REO (F31) had better thermal properties than the control (AS) film. The polyphenol content of films was in the range of 1.8 to 6.11 mg GAE/g dried films. The percentages of DPPH inhibition were between 15 to 53%. The film with highest AnchCNC and REO (5% AnchCNC, 6% REO) had the highest levels of polyphenols and DPPH inhibition. The results showed that the polyphenol content and antioxidant activity of films were increased proportionally with increasing AnchCNC and REO content. The total polyphenol concentrations that migrated to aqueous medium at 30 °C after 7 days were in the range of 17 to 60 mg GAE/kg food simulant for water food simulant. As expected, film sample F33 with (5% AnchCNC, 6% REO) had the highest concentration for the migration of polyphenols. The initial release rate of polyphenol, νo for film, F33 at four different temperatures, determined from the overall firstorder kinetics model were in the range of 8.3 × 10-7 to 36 × 10-7 g/s. The release of polyphenol into water food simulant at different temperatures were consistent to short-term and long-term diffusion models with diffusion coefficient values between 5.0 × 10-12 and 9.1 × 10-16 m2/s. The films produced displayed good antibacterial activity against the growth of E. coli, L. monocytogenes and S. aureus on meat products. The film with AnchCNC (5%) and REO content of (6%) were found to extend the shelf-life of meat beyond 50%, suggesting that the film may have great potential in active packaging for extending the shelf-life of foodstuffs. The findings implied that the film would have significant potential for active packaging to increase the shelf life of food products with good mechanical and barrier capabilities.Item Development and Quality Assessment of value-added Fish Products(Addis Ababa University, 2021-12) Meron Teklu; Shimelis, Admassu (Prof.)The goal of the present study was to develop and assess the quality of Value added fish products derived from Oreochromis niloticus tana (Nile tilapia). Fish ball and fish nuggets Products were prepared, recorded, and analyzed using different parameters like proximate analysis, microbiological analysis, physicochemical analysis, texture analysis, and sensory analysis. The moisture, protein, fat, ash and carbohydrate contents of fish balls The study revealed that samples varied between 50.03% - 80.35%, 13.30% - 18.08 %, 11.83% 14.83 %, 1.90% - 2.07% , 10.97 % - 15.02% respectively.Fish Nuggets (FFA) product had a better acceptability during storage at 4°C for 6 days in microbiological parameters like TPC, E. coli and S. aureus as well as Chemical analysis showed that fish ball and fish nuggets contained high protein, fat, due to frying process. Moreover, the textural properties which include hardness, cohesiveness, springiness and chewiness of the products exhibited more firmness after cooking (p<.05). Moreover, the sensory evaluation showed that acceptability of fish nuggets was more than that for fish ball. These results showed that fish nuggets had higher quality indicators rather than fish ball.Item Development and Quality Evaluation of Biscuit and Cookies Made from Wheat Flour Supplemented with Kocho Powder(Addis Ababa University, 2021-12) Dinkitu, Jaleta; Shimelis, Admassu (Prof.)Biscuit and cookies are ready-to-eat inexpensive food products that are consumed among all age groups. This thesis work was performed to develop and quality evaluation of biscuits and cookies made from wheat flour supplemented with kocho powder. The wheat flour and kocho powder were used to develop biscuits (80:20, 70:30, 60:40, and 50:50% of substitution ) and 100% wheat flour as a control.The data generated were statistically analyzed by ANOVA using SPSS. Proximate analysis were carried out on the flour,biscuits and cookies samples.And also water and oil absorption capacities were carried out on the flour and texture and color analysis were carrried out on the biscuits samples.The results of proximate composition, energy content and water activity shows that the wheat flour(control flour) contained 14.8% of moisture content, 0.45% 0f ash content, 10.237% of protein value, 1.5% of fat value, 0.5% of fiber, 72.52% of carbohydrate value, 344.5kcal/100g and 0.528% of water activity. The results indicated that the control flour showed higher level of moisture content, protein content, fat content, energy value and lower level of ash content, carbohydrate content, fiber content, water activity content while composite flours showed higher level of ash content, carbohydrate content, fiber content water activity content and lower level of moisture content, , protein content, fat content and energy value. Improvements were also noted in mineral contents such as magnesium, iron and calcium in biscuit produced from the composite flour of wheat supplemented with different levels of kocho powder. Physical (weight, thickness) and sensory (taste, colour, texture, appearance, flavor, overall acceptability) attributes of biscuits made from kocho powder and wheat flour were analyzed. The sensory acceptability was evaluated by a seven point’s hedonic scale. As the kocho powder addition decreased from 50 % to 20 %, the thickness, and the sensory attributes (taste, flavor, appreance,color,texture preference and overall acceptability) of the biscuits got increased. From the result, texture, taste, Colour, flavor,appearance and overall acceptability did not show any significant difference(P≥0.05) among different samples. As a result, the high nutritive and flavor rich biscuits and cookies generated in this study are to provide health benefits.Item Evaluation of Bashekala Barley-Wheat Flour and Starch Properties for Biscuit Production(Addis Ababa University, 2022-02) Teketel, Geto; Shimelis, Admassu (Prof.)This study examined the properties of the bashekala barley-wheat flour and starch for biscuit production. The effects of the bashekala barley-wheat flour blends on proximate analysis, functional properties, pasting, farinograph analysis, and sensory analysis were evaluated using standard laboratory procedures, and statistics were conducted using ANOVA and SPSS. The bashekala barley-wheat blend was developed using the D-optimal mixture design software. The proximate analysis of the blend bashekala barley-wheat blend ratio (20:80) revealed a significant effect (p<0.05) on the crude protein, moisture, ash, fat, carbohydrate, and crude fiber content. As per sensory evaluation of biscuits results (20:80%) and (60:40%) blend rations made biscuits with superior sensory properties, and excellent acceptability. Further, as bashekala barley flour substitution levels increased, the texture profiles of biscuit products increased with biscuit hardness, the crust color of the biscuits changed from dull to darker brown, but biscuit fracture ability decreased as bashekala barley flour substitution levels increased. The farinographic properties of blended ratio flour (20:80%) (25:75%), (40:60%), and (100/0%) was significant with (p<0.05) between WA, DS, DDT, and FQN respectively. In conclusion, bashekala barley flour water absorption properties are superior, the 20% bashekala barley flour blend ratio had superior sensory characteristics, and its flour substitution could significantly contribute to the development of biscuits.Item Development of Weaning Food from a Blend of Oat, Rice and Cowpea Flour(Addis Ababa University, 2021-12) Sewbesew, Tefera; Adamu, Zegeye (Assoc. Prof.)Cereals and legumes are highly cultivated plants in Ethiopia.They contain high macro and micronutrients, but they have anti-nutritional factors by nature which limit the bioavailability of food nutrients.This study focused on development of weaning food from Oat, Rice, and Cowpea flour for the age group of 6 to 24 months babies. This age is a critical period of mental, physical, and intellectual development.Raw materials were selected based on nutritional availability. Roasting method was used at 100,120, and 140 oc, Blending ratio refers 60 to 70% cereals and 30 to 40% legumes.Ratio1(50% Oat,10% Rice,40%Cowpea) contained higher protein content than Ratio2 and Ratio3 this is because of the avalibilty of high amount of Cowpea. Optimization using Minitab 17 software was used in order to formulate the nutrient and to compare the product from commercial product which is FAFFA flour.The roasting process and blending ratio had a significant (P<0.05) effect on proximate composition, functional properties, anti-nutritional factor, mineral content, and microbial analysis.According to optimized result P2,P3&P9 labled weaning products have been found good nutrietious especially P3(ratio1with140oc roasting temperature) was selected of having optimum protein and energy containing 18.1%protein, 4.9%fat, 70.8%carbohydrate and 400.2kcal energy.As roasting temperature incresed the same ratio of protein,fat, ash and mineral contents were significantly (P<0.05) increased but moisture and fiber contents were decreased. WaterAbsorption Capacity(WAC) and Oil Absorption Capacity(OAC) of the formulated products ranged between 2.01 to 2.85 and 1.57 to 1.94ml/g,respectively,which were higher than the raw material values.Bulk density of the formulated products were lower than the raw material values due to roasting.After processing both phytate and tannin content of formulated products were decreased due to roasting so increased bioavalablity of products.Item Development of gluten-free biscuit from a blend of Teff, Sorghum and Cowpea Flour(Addis Ababa University, 2021-12) Rebka, Temam; Adamu, Zegeye (Assoc. Prof.)The study was conducted to develop gluten-free and protein-rich biscuit to achieve nutritionally improved quality product and reduce celiac problem which arises with gluten content. Teff (Boset variety), Sorghum (Melkam variety) and Cowpea (Bole variety) were collected from Debrezeit and Awash Melkasa Agricultural Research Centers. The raw materials were cleaned, soaked(cowpea), dehulled(cowpea), dried(cowpea), milled and sieved before blended flour preparation. Blend proportions of Teff, Sorghum and Cowpea were prepared as S1 (65%: 20%: 15%), S2 (40%: 25%:35%) and S3 (50%:30%:20%) ratios, respectively using D-optimal design software. In this study, proximate composition, functional properties, anti-nutritional properties, mineral content and sensory analysis were conducted. Biscuit samples were prepared with temperature controlled oven at 205ᵒc for 10 minutes. The results showed that the protein and fat contents of biscuit product were directly proportional to the amount of cowpea flour added in the blend proportion, biscuit having 35% cowpea or S2 being the highest ( 15.4g/100g and 8.5g/100g). Mineral content increment for Fe, Zn and Ca was 9.33 to 12.05, 2.62 to2.95 and 95.34 to 116.3mg/100g respectively with increasing teff proportion. Tannin (23.08mg/100g) and phytates (439.23mg/100g) were higher in higher cowpea and teff addition respectively. Functional properties such as water absorption capacity(2.15ml/gm), oil absorption capacity(1.73ml/g) and bulk density (0.94g/ml) registered the highest values.. pH values of samples were 6.39, 6.49 and 6.45 respectively for S1 (65%: 20%: 15%), S2(40%: 25%:35%) and S3(50%:30%:20%) in the blend proportions respectively. The highest overall sensory acceptability score was 7.8(S3) which was liked moderately next to the control biscuit sample. S3 also scored highest in texture (7.65), appearance (7.8) and taste (7.65) parameters whereas the color (7.7) of S1 biscuit sample was better liked by panelists.Item A Comparative Study on Physicochemical Properties of Starch Isolated from Varieties of Cassava Grown in Ethiopia and its Evaluation as Bio-edible Packaging Film(Addis Ababa University, 2021-09) Desta, Geta; Shimeles, Shumi (PhD)Starch extracted from different sources and varieties show various physicochemical properties which affect its applications. Considering this, the aim of this research was to study the physicochemical properties of starches extracted from Qulle (Q) and Kello (K) cassava varieties and their evaluation for making bio edible packaging film. Starch was extracted by wet extraction method using distilled water. The study showed that the proximate compositions of Kello starch were: moisture content (11.4%), ash content (1.1%), crude fat content (0.11%), protein content (0.52%), crude fiber content (0.01%) and total carbohydrate (86.85%). Whereas for Qulle starch: moisture content (10.6%), ash content (0.13%), crude fat content (0.13%), protein content (0.35%), crude fiber content (0.09%) and total carbohydrate (88.7%). Furthermore, the content of amylose and amylopectin of each varieties of starch were calculated and found to be 26.29 %( Q), 73.7 % (Q) while, 19.16 % (K) and 80.83% (K) respectively. It was observed that the high peak and breakdown viscosity values found for Kello starches is due to low amylose content. Films were prepared by casting method and the results showed that for Kello film: moisture content (13.25%), transparency (11.625%), thickness (0.13mm), tensile strength (13.554MPa), water absorption (33.08%) and solubility (26.37%).While for Qulle film: moisture content (11.62%), transparency (12.30%), thickness (0.12mm), tensile strength (14.983MPa), water absorption (29.39%) and solubility (28.85%). Generally, Qulle starch was better for the development of bio-edible packaging film due to its low moisture content, low ash content, low protein content, and contain high amount of amylose.Item Microbial and Mycotoxin Decontamination of Red Pepper (Capsicum annuum L.) using Selected Emerging Food Processing Technologies(Addis Ababa University, 2021-12) Henock, Woldemichael; Shimelis, Admassu (Prof.); Toepfl, Stefan (Prof.)Mycotoxins are natural secondary metabolites of fungi occurring in foods which can cause adverse health effects. Contamination of foods with microorganisms and mycotoxins can occur at various stages along the value chain, and spices are not exception. Red pepper (Capsicum annuum L.) is one of the major spices consumed globally, recognized for its distinctive aroma, color, pungency and nutritional value. It also significantly contributes to the national economy for high producing countries like Ethiopia. However, natural contamination and occurrence of fungi with subsequent production of aflatoxins (AFs), ochratoxin A (OTA) and other mycotoxins in red pepper have posed a serious concern in the food system. Though mycotoxin contamination of red pepper has been evidently studied and well documented, studies regarding efficient decontamination techniques are scant. Therefore, this study aimed to investigate the impact of selected emerging food processing technologies (electron beam (e-beam), pulsed light (PL) and high pressure processing (HPP)) on the decontamination of naturally occurring microorganisms and mycotoxins in red pepper. Initially, the physicochemical, functional, thermal, oxidative stability and rheological properties of red pepper powder and paste were characterized. The compositional analysis showed that the red pepper powder contained 14.50, 44.00 and 7.57 g/100 g of crude fat, crude fiber and ash, respectively. The concentration of total phenols (TP), carotenoids and antioxidants activity of the powder were 1.04 g GAE/100 g, 374 mg c/100 g and 38.61 μmol TE/g, respectively. Findings on functional properties revealed that the bulk and tapped density were 395.1 kg/m3 and 583.4 kg/m3, respectively, indicating higher compressibility of the powder. In contrast, Hausner ratio (1.48), Carr‘s index (32%) and angle of repose (45°) indicated poor flowability of the powder. Particle size distribution also indicated that the volume weighted mean values D[4,3] of the powder and paste were 262.20 and 201.46, respectively. Emulsifying, oil and water absorption capacities of the powder were 47.5%, (1.41 to 1.73) g/g and (0.86 to 2.29) g/g, respectively. Higher glass transition temperature was observed for the powder (62.54 °C) than the paste (45.64 °C). The induction period indicated that red pepper was more stable against oxidation in powder form (5.2 h) than in paste (3.2 h). Rheological analysis revealed that the paste exhibited shear-thinning behavior at 25 °C. As aforestated, red pepper is an important spice with vital nutritional composition and techno-functional properties, and with immense potential for industrial application and product development. However, in recent years, frequent contamination with fungi and mycotoxins posed health concerns and hampering the export market. Thus, investigations on efficient decontamination techniques are critical. The first evaluated treatment was e-beam with variable doses of up to 30 kGy. Significant (P<0.05) reduction of yeasts, molds and total plate counts (TPC) were observed upon e-beam treatment, dose-gradient wise. Treatment at 6 kGy significantly (P<0.05) reduced yeasts and molds by 3.0 and 4.4 log CFU/g, respectively. Similarly, TPC was reduced by 4.5 log CFU/g at 10 kGy. Inactivation of yeasts and molds followed first-order kinetics, while TPC exhibited non-linear model fitted to Gompertz function (R2 = 0.9912). E-beam treatment was not efficient for the degradation of AFs but indirectly controlled their production by inactivation of mycotoxigenic molds. In fact, at the maximum e-beam treatment of 30 kGy, OTA was reduced by 25% retaining >85% of TP, carotenoids and antioxidants activity. Importantly, ‗slight differences‘ with the treatments on total color difference (ΔE*) were observed. Overall, e-beam treatments up to 10 kGy were effective in decontaminating the natural microbiota with minimal adverse effects on the physicochemical qualities of red pepper powder. The other decontamination treatment investigated in this study was PL. Red pepper powder was exposed to PL treatments up to 61 pulses, with an overall fluence ranging from 1.0 to 9.1 J/cm2. The highest fluence applied (9.1 J/cm2, 61 pulses, 20 s) resulted in 2.7, 3.1 and 4.1 log CFU/g reduction of yeasts, molds and TPC from 4.6, 5.5 and 6.5 log CFU/g, respectively. At the same fluence level, aflatoxin B1(AFB1), total AFs and OTA were reduced by 67.2%, 50.9% and 36.9%, respectively. There was a proportional increase in temperature from the absorbed PL energy, reaching maximum of 59.8 °C. The inactivation of both microorganisms and mycotoxins followed first-order kinetics (R2>0.95). With the lowest fluence (1.0 J/cm2), carotenoids and antioxidants activity reduced significantly (P<0.05). However, at higher fluence of 6.9 and 9.1 J/cm2, TP concentration increased. For all investigated PL intensities, there was a significant (P<0.05) change in color values of L* and b*. However, there was ―slight differences‖ in the ΔE* compared with untreated sample. The other emerging technique evaluated for decontamination of microorganisms was HPP. Predictive models of HPP treatments were developed and holding time (30–600 s) and pressure (100–600 MPa) were optimized. Treatment at 527 MPa for 517 s reduced TPC by 4.5 log CFU/g. Yeasts and molds counts were reduced to 1 log CFU/g at 600 MPa for 315 s. Within the treatment range, TP, carotenoids and antioxidants activity were 0.28 to 0.33 g GAE/100 g, 96.0 to 98.4 mg c/100 g and 8.70 to 8.95 μmol TE/g, respectively. Slight increase in these attributes by 2.5–6.7% was observed with increasing holding time and pressure. The ΔE* values up on treatments ranged from 0.2 to 2.8, which was within the category of ‗imperceptible‘ to ‗noticeable‘. Experimental results were fitted satisfactorily into quadratic model and higher R² values (0.8619–0.9863) and non-significant lacks-of-fit (p-value > 0.05) proved good prediction of the model. The optimum treatment of red pepper paste was at 536 MPa for 125 s for maximum desirability (0.622). Validation experiments confirmed comparable percentage of relative errors (0.7 to 16.7%) among predicted and experimental values. With the approaches of the present study, e-beam, PL and HPP could be used as alternative technologies for the decontamination of naturally occurring microorganisms and mycotoxins in red pepper with minimal changes in quality attributes.Item Production and Characterization of Quality Biscuits from the Blend of Banana and Wheat Flours(Addis Ababa University, 2021-11) Koak, Mot Kuechuor; Adamu, Zegeye (Assoc. Prof.)Banana (Musasp.) is cheap and has been grown in most parts of Ethiopia. In its green stage, banana contains mainly carbohydrate especially starch; therefore, it is suited to use as the source of starch and flour. Then banana flour was used for starch isolation using 0.05N NaOH. The gelatinization temperature ranges obtained from differential scanning calorimetry (DSC) were 66.50°C, 75.16°C and 86.54oC for starches. The study was also carried out to determine the biscuit making potentials of cooking banana and wheat flour blends. Accordingly, all the banana flour and starch samples were characterized, and biscuit samples were subjected to laboratory analysis for proximate and minerals using standard methods. Supplementation of wheat flour with cooking banana flour significantly p<0.05) increased the ash (1.34-2.10%), crude fibre (1.06-2.81%) and moisture contents (2.77-8.91%) of the cookies while a decrease in the fat (31.37-29.28%), protein (8.31-7.53%) and carbohydrate (55.15-49.37%) was observed. The sensory results also showed that cookies with 10% substitution of cooking banana flour were preferable for colour, texture, aroma and taste, and this compared favourably with 100% wheat flour cookies. The minerals were 5.89-6.12mg Ca, 0.48-0.82mg Fe, and 22.10-23.93mg P. The present result showed that cooking banana flour has high potential as value added ingredient in cookies production for household utilization.Item Investigation of Heavy Metals Status in Vegetables Grown at Awash and Jemo-3 Farm Sites, Ethiopia(Addis Ababa University, 2021-10) Mersha, Mengiste; Kumsa, Delessa (PhD)Food safety is a big public concern around the world. Vegetables are an essential ingredient in the human diet as they contain nutrients and trace elements which have potential health benefits. They are known to accumulate trace metals which are essential as well as toxic. Ingestion of vegetables containing heavy metals is one of the main routes by which they enter the human body, which gradually causes human diseases. An optimized wet acid digestion procedure has been adopted to digest the plant and soil samples. The validity of the method was evaluated by spiking the sample with a standard of the selected metals. For water samples, the United States environmental protection agency (USEPA) 3005A (1992) method was applied. From analysis of soil the mean concentrations (mg/kg) of Pb and Cr were observed to be 18.77±0.54, 30.89 ±0.18 respectively. However, Cd was not detected. For irrigation water, the levels of all heavy metals were found to be below the detection limit. For vegetables, only lead was detected and its mean concentrations (mg/kg) were obtained to be 0.31 ±0.02 for cabbage, 0.40±0.03 for lettuce and 0.33 ±0.06 for spinach. The metal concentrations determined on the farm were compared to the standards, and Pb in vegetables was found to be above the permissible limit. The objective of this research was to investigate the source and level of heavy metals (Pb, Cr, and Cd ) contamination in irrigation water, soil, and various types of vegetables, including cabbage, lettuce, and spinach, cultivated on an Awash vegetable farm. The research findings made it clear that the contamination of those soil and vegetables with these heavy metals was primarily due to their geogenic origin, so the study area should be treated to reduce the health risk of humans due to exposure to toxic levels.Item Effects of Blending Ratio of Eggplant and Wheat Flours on The Functional Properties of Cookies(Addis Ababa University, 2021-09) Kuribachewu, Mengesha; Kumsa, Delessa (PhD)Eggplant contains a high concentration of phytochemical compounds and nutrients important for life. Avoiding losses and increasing consumption will be easier with flour processing. The goal of this research was to study the effects of blending ratio of eggplant and wheat flours on the functional properties of cookies. In the Design Expert software Central composite design method was used for different level of operations and determining the drying parameters in different drying temperature, air volumetric flow rate and time and hot thin layer dryer was used to dry eggplant, and Folin-Ciocalteu techniques were used to measure total phenolics extract by methanol, while aluminum trichloride (AlCl3) was used to estimate total flavonoid content. Free radical scavenging activity was determined by 2,2-diphenylpicryl-1-picrylhydrazyl. Eggplant and wheat flours were used to develop cookies (10:90, 15:85 and 20:80% of substitution) and 100% wheat flour as a control. The proximate composition of eggplant flour, wheat flour, and composite flour samples were (moisture 8.0,9.0 and 8.4%); (Ash 6.8, 0.57and 2.4%); (Crude protein 10.44, 9.95 and 13.48%; (Crude fat 1.75, 0.9 and 1.75%); (Crude fiber 16.09, 2.04 and 5.52%) and (energy 285.19, 358.08, and 343.49KJ/100g) respectively. The phytochemicals of eggplant flour, wheat flour, composite flour and cookies made by composite flour were determined and the values indicated 1.36, 0.13, 1.53, 0.93 mg/100g of flavonoid. Total phenol 1.55,0.13,2.32 and 0.76mg/100g respectively. Free radical scavenging activity was determined by IC50 value. Cookies made by composite flour showed higher total phenolic content (TPC), total flavonoid content (TFC) and free radical-scavenging effect compared to control, also in terms of health benefit composite flours are selected. As a result, the antioxidant-rich, high-protein cookies generated in this study are anticipated to provide health benefits, such as lowering oxidative stress and the diseases associated with it.Item Effects of Gum Arabic (Acacia-Senegal) on Dough Rheological Characteristics and Quality of Gluten Free Bread(Addis Ababa University, 2021-07) Tullo, Tubaro; Kumsa, Delessa (PhD)Gluten free-bread is recently gaining popularity due to its suitability for people suffering from celiac disease. A study was conducted to investigate the effects of gums grown in Ethiopia on the dough rheological properties and on final quality of gluten-free bread made from maize. Gum from each Varity was used at a concentration of 3% on the flour weight basis and wheat and maize was considered as control. The dough rheological properties such as farinographic, pasting, gaseous release and dough development properties were analyzed. The control (wheat and maize) and gluten-free bread samples contain a gum were analyzed for their proximate composition, loaf and specific volumes, texture profile and sensory analysis. In addition, the pH, moisture content, viscosity, water and oil holding capacities, and functional group and gelatinization properties of the gums were determined. The results indicated that the addition of local gums into maize flour significantly reduced the water absorption capacity and degree of softening of the doughs. The addition of Gumero gum resulted in the lowest water holding capacity of the maize dough (52.95%). All the gums used in the experiment improved the stability of maize dough; however, only the dough containing Gumero gum had significantly higher dough development time (10.35 min) than the control maize dough (4.45 min). All the pasting properties except pasting temperature were considerably affected by the addition of the local gums. The dough containing Gumero gum exhibited the lowest peak viscosity (430.50 RVU). The doughs containing the Humera (65.77%) and Harar-Sidamo (65.61%) gums had significantly high gas retention capacity compared with the control dough (62.56%). The dough mixed with Harar-Sidamo gum (3.10 mm) also had significantly higher height of the dough at the end of the test than control dough (0.00 mm) and the one containing Humera (1.85 mm) and Gumero (1.65 mm) gums. The loaf volume and specific volume of the bread were affected significantly by the incorporation of the local gums. The gluten-free bread made with Harar-Sidamo gum had considerably higher values of loaf volume (314.87 cm3) and specific volume (2.03cm3/g) than the control maize bread and the one made with Humera and Gumero gums. The maize bread had the highest firmness value (1844.91 g) and the maize bread mixed with Harar-Sidamo gum had the lowest firmness (1580.00 g). The addition of gums improved the ash and fiber contents as well as the sensory attributes of the gluten-free breads. However, the crude protein, crude fat and carbohydrate contents were also reduced with addition of the local gums. In conclusion, among the three gums, HSG resulted in better dough characteristic and quality attribute of bread nearly comparable to bead wheat.Item Development and Quality Evaluation of Okra (Abelmoschus Esculentus) Based Instant Noodle for Pregnant(Addis Ababa University, 2021-07) Molla, Abeje; Adamu, Zegeye (Asso. Prof.)In poor nations, promoting and eating indigenous vegetables could assist to relieve food insecurity and malnutrition. Noodles are the most extensively consumed foods on the planet in terms of national consumption, next to bread. This research began with the development of an instant noodle that employed okra and cornflour after mixes were designed (okra: corn flour ratio of 25%:75%, 35 %:65%, 45 %:55%, and 55 %:45%, at steaming temperatures of 95℃, 105℃, and 115℃.) by D-optimal design expert version 7.0. software. Results were analyzed using Minitab version17 using fisher pairwise comparison test at a significance level of alpha 0.05. Total folate (μg/100g) ranged from 85.62±0.40 to 235.49±0.62, making the noodle folate-rich enough to meet the WHO's daily folate requirement recommendation for pregnant women (500-600μg/day) to prevent neural tube defects (NTDs) which is improper cell division in DNA formation (facing about 50% of Ethiopian pregnant as reported by Tadesse et al., 2020) and other folate-deficiency-related illnesses. A 55 percent okra flour noodle steamed at 95°C had the highest content of folate. Proximate, functional, microbiological, texture and sensory attributes of the instant noodles were investigated. The moisture (%), crude ash (%), crude fat (%), crude protein (%), carbohydrate (%), crude fiber (%), and gross energy (kcal/100g) ranged from 4.45±0.00 to 6.80.0±0.01, 3.02±0.00 to 6.54±0.01, 2.00±0.01 to 3.61±0.00, 14.04±0.94 to 17.19±0.57, 58.49±1.65 to 66.90±0.33, 7.46±0.00 to 11.36±0.0, and 324.66± 0.07 to 351.18±0.02, respectively. Proximate results indicated that increasing the quantity of okra flour in the noodle sample increased the proximate compositions significantly at 55% okra flour and 115°C. Water absorption (%), solubility (g/g), and soluble loss (g/g) ranged from 0.72±0.00 to 0.87±0.00, 75.27±0.32 to 93.69±0.01 and 0.12±0.00 to 0.87±0.00, respectively. The findings revealed that water absorption, solubility, and soluble loss were all increased significantly with the okra ratio and steaming temperature. Total microbial load testes by TPC resulted in zero microbial colonies. A texture profile test indicated that as the temperature and okra flour percentages increased, the force and time needed to break the noodle decreased, but the least force required to chew (break) the sample containing 25% okra and 75% corn steamed at 105°C was 3.00N. The preference test by hedonic scale showed that samples having 25% okra at 115°C and those containing 55% okra at 95°C scored 7.78 and 5.86 respectively, indicating good consumer acceptance.