Food Engineering
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Browsing Food Engineering by Author "Adamu, Zegeye (Assoc Prof.)"
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Item Development of Anchote (Coccinia Abyssinica) based Ready to Eat Baby Food Products(Addis Ababa University, 2019-12) Iyob, Deresa; Adamu, Zegeye (Assoc Prof.)Anchote is an endemic and potentially valuable crop of Ethiopia and nutritionally, it is a good source of minerals and fiber. The crop is used as food security plant during food shortage since they are drought-tolerant and high yielding. This study was aimed at developing and enhancing the value of anchote based ready to eat food products for the babies in the age group of 6 to 18 months using drum dryer, and to evaluate their suitability and wholesomeness. Accordingly, anchote, oat and soybean were selected based on their nutritional value, affordability and availability to develop a protein and energy complementary food. Response surface methodology (RSM) was implemented to study the effect of drum drying process parameters on proximate and mineral composition, antinutritional factors, physical and functional properties, microbial load and sensory quality attributes. By applying mixture design D-optimal software, a formulation containing 54.11g/100g anchote, 26.59g/100g oat, and 19.28g/100g soybean flour was selected as the best source of energy (380.03kcal) and protein (18.01g/100g). The drum drying process variables were: drum temperature (145 and 160°C), drum speed (200 and 300 rpm) and product particle size (0.6 and 0.8mm). The optimum protein and energy contents of the product obtained at 145 o C drum temperature, 200rpm drum speed and 0.6mm particle size were 18.68% protein, 5.3 % fat, 4.27% ash, and 68.94 % total CHO and 399.82kcal/100g of utilizable energy. The vitamin B2, Ca, Zn, Fe, Mg and K contents of drum dried products were (0.48, 168, 0.51, 1.46, 86 and 54 mg/100g) higher than the raw formulated flour (0.46, 148, 1.24, 0.22, 81.03 and 68mg/100g). The antinutritional reduction of phytate was from 190.34 to 113.41mg/g and that of tannin was from 12.23 to 3.89mg/g. The functional properties: namely water absorption, oil absorption, swelling power, dispersibility and solubility (2.75g/mL, 1.48mL/g, 3.75g/g, 65.77% and 63.2%) of the drum dried products were higher than that of formulated raw flour (1.26ml/g, 1.42mL/g, 2.68g/g, 50.5% and 41.23% ) due to starch gelatinization. The sensory results of the product produced at a drum temperature of 160 C, drum speed of 300 rpm and particle size of 0.6mm was perceived as the most acceptable ones. Microbiological analysis results showed that Coliform and E. coli were not detected in all products. The total plate count, yeast and mold count analysis showed results in the safe limit according to FAO and WHO recommendations. The optimum protein and energy contents of the product obtained at 145 o C drum temperature, 200rpm drum speed and 0.6mm particle size content have been found to be ideal operating o variables for production of anchote-based ready to eat baby food product.Item Enhancement of Quality and Storability of Avocado (Persea americana ) Fruit using Blend of Aloe Vera Gel and Corn Starch as Surface Coating(Addis Ababa University, 2019-12) Helen, Berihu; Adamu, Zegeye (Assoc Prof.)Avocado has a fairly short shelf life and is included in climacteric fruits. The search for biodegradable, safe, healthy and environmental friendly treatments for increasing storage period of fruits has led to the use of edible, biodegradable films or coatings. This research evaluated the use of Aloe Vera and corn starch as bio-preservative, which are an economical and environmentalfriendly method. The study was conducted to check the efficacy of aloe Vera gel, corn starch and composite of the two as an edible coating so as toenhance storability of avocado. The treatment combinations were T0 = control, T1= corn starch (2.5% )T2= aloe Vera and corn starch (2.5%, 2.5% )and T3=Aloe Vera gel (1% ).The physio-chemical properties, hardness and decay percentage ofthe fruits were observed up to 25 th day of storage.Weight loss; pH; color; firmness; vitamin C; TA and TSS were recorded in interval of 5 days for 25 days of storage. Aloe Vera gel and combination of the aloe Vera with corn starch coated fruits showed minimum physiological loss in weight, minimum shrinkagepercentage, good color retention, lesser loss in titrable acid content as compared to uncoated ones.It was also found that aloe Vera gel subsequently helped in reducing the ripening rate of fruitswhich was found from the slower rate of total and reducing sugar development. Aloe Vera coatingwas very effective in reducing vitamin C loss and also helped to reduce the decay percentage.The control fruits started deteriorating before the 8 th days and only few fruits survived up to the 11 th days, whereas, storability extended to 25 days for majority of aloe Vera gel alone and with that of combined coating film coated fruits. At the end of the storage period, uncoated avocado fruits showed 21.02% loss in weight, whereas coated avocado fruits with corn starch (T1 ) showed 16.89%, coated avocado with aloe Vera gel (T3 ) and combination the two (T2 )were 9.56% and 9.48% by weight loss, respectively.The study revealed that the coating of aloe Veragel with 1% and a combination of both with (2.5%, 2.5% )was effective in retaining quality of avocado fruit over a storage period of at least 22 and 25 days respectivelyThe effect of coating with Aloe Vera gel and corn starch on microbial count of avocado has showed significant (p<0.05 )changes. Aloe Vera gel was effective against plant pathogenic fungi. Both the starch and aloe Vera gel edible coating was found good enough to ensurehardness/firmness of the fruits during storage consequently it can be concluded that aloe Vera and corn starch are a good barriers of avocado storage.