Small-scale baking ovens are built by the local workers and usually no scientific principles are followed to design and build of it. Modern scientific principles and procedures are followed to design and fabricate the baking ovens using low-cost materials. The major drawbacks of this type of traditional oven are: improper control of baking temperature; contamination of products with ashes during heating and excess cost for heating. This study aimed at modeling heat and mass transfer during baking, and evaluating the quality characteristics of bread and cake. The problems were identified by conducting a one-time cross-sectional survey, and the heat and mass transfer were modeled by designing and fabricating an improved oven. This model predicted the bread temperature and moisture content at 160, 170, 180, 190 and 200°C oven temperatures. The result indicated that increasing the oven temperature from 160 to 200°C increased the bread crust temperature from 101.58 to 158.69°C. However, the temperature and weight of bread increased gradually with increasing baking time up to 18-20 min and then started declining until it reached equilibrium after 30 min. The weight loss of bread increased with increasing bread temperature. The model predicted fairly accurate bread temperature and weight loss. It predicted 20 to 132°C against the observed 22 to 115°C during baking at 200°C oven temperature, 0 to 40% weight loss against 0 to 49% observed weight loss. The developed improved oven required 25% less time for baking bread and cake compared to the traditional one. Loaves of bread baked in the improved oven had 27.4% lower moisture content, 660 cm3 higher volume, and 408 g lower crumb firmness value compared to the conventional baking process. The improved baking oven is, therefore, more efficient than traditional baking ovens in terms of heat and mass transfer, baking time and product quality.
Key words: Mass transfer, Design, Baking oven, Temperature, Weight loss
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