Optimization of Absit Process Factors to Improve the Physicochemical and Sensory Quality of Teff Injera
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Date
2018-06-03
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Addis Ababa University
Abstract
Teff Injera is the staple Ethiopian fermented bread processed from fermented tef [Eragrostis tef (Zucc.) Trotter] grain flour. Absit is a portion of the fermented dough diluted to paste with water and then cooked and gelatinizes the starch which enhances proper fermentation of the batter. The proper fermentation process of dough can be enabled and attained by appropriate absit cooking parameters ( dough level %, agitation speed rpm and adding temperature OC) to make good injera. There is no research made about absit process factors before to improve the physicochemical and sensory quality of teff injera. This study aimed to optimize the above absit cooking process factors to improve the physicochemical and sensory quality of teff injera using Box-Behnken response surface methodology (RSM). Absit process factors ( (dough level(10-20 %), agitation speed(200-300 rpm) and adding temperature (45-65OC)) were considered and made 15 samples of absit including 3 replicates using RSM. The investigated responses were viscosity , sensory attributes (color, taste, texture, number of eyes, eye size, eye distribution, top & bottom surfaces and overall acceptability) and lightness (L* value) of the injera. RSM with Box-Behnken Design was used to develop and optimize absit process factors in response with the baked injera. Moreover, Both numerical and graphical optimizations were carried out to determine the optimum values of injera in terms of taste, texture, number of eyes, eye size, eye distribution, top & bottom surfaces and overall acceptability. The sensory scores for color, taste, texture, number of eyes, eye size, eye distribution, top & bottom surface and overall acceptability were 5.63 to 7.72, 5.22 to 6.21, 56.63 to 72.58 , 47.47 to 65.05, 57.11 to 74.88,53.09 to 77.62, 41.26 to 66.26, 46.76 to 71.71, 51.34 to 77.80 and 50.03 to 68.38, respectively, while the L* value(lightness) ranged from 60 – 75.78%. The optimum process factors of absit while considering taste, texture, number of eyes, eye size, eye distribution, top & bottom surface and overall acceptability were dough level of 11.06 %,agitation speed, 200rpm and temperature, 45 oC with a desirability of 0.91. The sensory scores for color, taste, texture, number of eyes, eye size, eye distribution, top & bottom surface and overall acceptability were selected as 64.84, 74.88, 74.61, 62.79, 68.16, 70.41, 68.27 % respectively. The study showed that all the absit process factors were important parameters influencing the physicochemical and sensory attributes of injera except the visual color, L*values and viscosity of injera.
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Keywords
Absit, Box-Behnken Design Teff Injera, Optimization, Response Surface Methodology