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| dc.contributor.author | Mehari, Gidey | |
| dc.date.accessioned | 2020-03-11T08:45:25Z | |
| dc.date.available | 2020-03-11T08:45:25Z | |
| dc.date.issued | 2020-03-11 | |
| dc.identifier.uri | http://hdl.handle.net/123456789/10187 | |
| dc.description.abstract | “Tella” (Local beer) is widely brewed in both rural and urban part of Ethiopia. The way of preparing tella depends on tradition and the economic situation. Even though, the basic processing steps are similar, every tella-maker seems to have their own recipe. This attributes tella to have different alcohol content and sensory values that could affect marketing and scaleup. Thus, it needs optimization, and development of protocol to scale-up the capacity and quality. This study is aimed at optimizing the process of tella production through evaluating effects of fermentation parameters (temperature, inoculums size (―tejet”) and fermentation time) on the total phenol content, titrable acidity, pH and alcoholicity of hull-less barley tella using Response surface method ology (RSM). ―Tella” was prepared according to existing standard methods and Central Composite Rotatable Designs (CCRD) was used for the experimental design and analysis. The findings of this study indicated that the variations of alcohol, polyphenol, titratable acidity and sensory acceptability levels of ―tella” were considerable due to the change in fermentation temperature, time and inoculum volume can be explained mainly by the quadratic models. The maximum alcohol content (5.6%) was produced by applying temperature and inoculum concentration of 25°C and 25%, respectively. This clearly describes that the effect of temperature and inoculum concentration on the fermentation rate is positive. The effect of inoculum concentration (25%) and temperature (250C) at constant fermenting time (6 days) constantly increased the titratable acidity to reached 0.96 g/L equivalent to acetic acid. The fermentation and inoculum concentration slightly increased the total polyphenol content 2660 mg/L equivalent to gallic acid at constant temperature (25°C). The overall sensory acceptability of the ―tella ―(local Ethiopian beer) increased at temperature (25°C) and inoculum concentration (25%) by keeping the fermentation time (6 day) constant. Moreover, the optimum levels of each response indicated that at least one of the factors has to be controlled to manipulate the others. Thus, the optimization and modeling work of study could be used as a potential source of information for further studies in ―tella” processing and production optimization, scale-up and marketing. | en_US |
| dc.language.iso | en | en_US |
| dc.subject | food technology | en_US |
| dc.title | Optimization of Hull-less barley fermentation process for “Tella” (Home brewed traditional beer) production in Ethiopia | en_US |
| dc.type | Thesis | en_US |
