THE STUDY OF SOME ENGINEERING PROPERTIES OF TEFF [ERAGROSTIS teff (ZUCC.) TROTTER] GRAINS AND ITS FLOUR

Abstract

This study was conducted to generate information on some engineering properties of teff [Eragrostis teff (Zucc.) Trotter] grains and its flour. Six teff varieties namely Quncho (DZ-Cr- 387), Felagot (DZ-Cr-442), Tesfa (DZ-Cr-457), Kora (DZ-Cr-438), Dukem (DZ-Cr-425) and Dagme (DZ-Cr-43B) were considered and their selection was based on their recent year coverage area and the expected future expansion. Each varieties were studied for physical, functional and rheological properties of the grains and the flours. The highest values of the physical properties of the grains, which included thousand kernel weights, hectoliter weight, angle of repose, bulk density, moisture content and crude fiber content of grains were 0.29 g, 95.67 kg/hl, 23.06°, 1.91 g/ml, 10.66 %, and 2.92% for varieties DZ-Cr-457, DZ-Cr-43B, DZCr- 438, DZ-Cr-43B, DZ-Cr-438, and DZ-Cr-425, respectively. The color values of L, a*and b* and particle size distribution of teff flour showed significant (P<0.05) differences among the varieties. The highest value of functional properties of teff flours which included water and oil absorption capacity, swelling power, dispersibility and water solubility index of the teff flour were 0.99 g/g, 1.42 ml/g, 11.99%, 74% and 19.61% for DZ-Cr-387,DZ-Cr-438,DZCr- 438, DZ-Cr-438 & DZ-Cr-457 and DZ-Cr-438 varieties respectively. The pasting properties of the six teff flour varieties such as pasting temperature, peak time, peak viscosity, final viscosity, break down viscosity, trough and set back viscosity values had ranged from 76 to 80.33 0C, 5.13 to 6.17 min, 880 to 1650 cP, 1511 to 1721 cP, 340.33 to 800 cP, 540 to 880 and 370.33 to 971 cP. The farinograph values had ranged from 47.37 to 50.85 %, 4.67 to 5.99 min, 3.62 to 4.24 min, 58.18 to 76.99 FU and 70.67 to 82.56 FU for water absorption, dough development time, dough stability time, mixing tolerance index and farinograph quality number, respectively. There were significant (P<0.05) differences among the varieties except dough stability time.