Browsing by Author "Legesse, Solomon"

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    Effect of Composite Flour Blend of Teff, Sorghum and Maize on Macro Nutritional Quality, Sensory Acceptability and Ph Fermentation Kinetics In Preparation of Injera
    (Addis Ababa University, 2015-06) Legesse, Solomon; Baye, Kaleab (PhD); Bekele, Tilahun (Assistant professor)
    The study attempted to investigate the effect of composite teff flour blend with sorghum and maize through optimization of formulation based on simplex lattice mixture design expert soft ware, on macro-nutritional composition, sensory acceptability and pH fermentation kinetics while looking for opportunities of preparing Injera with an affordable cost from such composites. The study was based on 14 experimental trials including four replication points on the contour triangle plot, three vertex points ([100% teff], [50% teff: 50% sorghum] & [50% teff: 50% maize]) and one point on the center edge (75% teff: 25% maize) which were generated from the soft ware with primarily defined constraint. Proximate and sensory acceptability determinations were carried out on the experimental trials resulting in content of protein (11.27-14.73)%, fat (1.79-3.59)%, crude fiber (5.65-9.57), total carbohydrate (6.97-19.82)%, total energy value (110.36-157.60)Kcal/100g and sensory acceptability scores from liked to extremely liked (color[4-5], taste[3-4], texture[3-4], odor[3-4], appearance[3-4] and over all acceptability[3-4]) based on 5-point hedonic scale which these response results were used for formulation optimization to finally came up with three optimized formulations; (formulation one [F1-control; 100% teff], formulation two [F2; 55.40% teff: 37.20% sorghum: 7.30% maize], formulation three [F3; 50% teff: 30.70% sorghum:19.30% maize], and formulation four [F4; 66.6% teff:19.80% sorghum:13.60% maize]) based on objective criterion. Further determination of proximate, sensory acceptability and pH fermentation kinetics were performed on the three optimized formulations and the control to result in content of (protein [11.34-16]%, fat [1.79-3.01]%, crude fiber [6.00-8.66]%, total carbohydrate [10.33-18.02]% & total energy value [132.39-162.37]Kcal/100g), sensory acceptability scoring from liked to very liked (color[3-4], taste[3-4], texture[3-4], odor[3-4], appearance[3-4] & over all acceptability[3-4]) within three days of preparation of Injera for all the optimized formulations plus the control, and maximum rate of change of pH per hour of (-0.011639 up to -0.040486) within 72 hours of fermentation. Composite teff flour blend with sorghum & maize had brought effect in different manner with regard to macro nutritional composition and sensory acceptability. With regard to pH fermentation kinetics, the fermentation rate of the three optimized formulations (F2,F3 & F4) was faster as compared to the control (F1) that the pH of the optimized formulations reached at a pH value of (3.901-3.906) within (22-26)hrs of fermentation while the control F1 reached at a pH value of 3.903 after 72 hours of fermentation; thus, by limiting the fermentation time of the optimized formulations from 72 hours to one & half days it could be possible to score comparable sensory acceptability responses with that of the control. Therefore, it was found out that F2 is preferable and healthy formulation especially for people whose life style is sedentary and not energy demanding while F3 and F4 are the preferred formulations for people who demand energy in any case. Key words: Formulation optimization;, design expert; pH fermentation kinetics; composite flour blen;, Injera.