Abstract:
Grain and flour's physical, rheological, functional, and other properties are vital in the
food industry. These properties and consumer acceptability of cookies may be affected by
variety and flour particle size. The impact of teff varieties and flour particle size on
physical, functional, and pasting properties, and the overall acceptability of teff flour
cookies, were explored in this study. Three varieties of teff grain (Bora, Jitu, and Filagot)
were milled and sieved to obtain the desired particle sizes of three flour fractions (360-
250, 250-160, and 160-90 µm) and classified as P1, P2, and P3 respectively. A factorial
design was used to carry out nine treatment combinations. Physical properties such as
angle of repose, particle size distribution, color for grain and flour, functional and pasting
properties, the mineral content of the flour, and cookies acceptability were determined. A
sieve analysis technique was used for particle size analysis. The color values were
determined by Hunter L*a*b* Aeros Spectrophotometer. The findings revealed significant
(P<0.05) differences among samples in most of the evaluated parameters. It could be
observed that the variety significantly (P<0.05) influenced the values of hectoliter weight,
bulk density, and angle of repose of grain with values of 91.07 to 94.13 Kg/hl, 0.86 to 0.97
g/mL, and 23.20 to 26.16 o
respectively. Varieties also influenced water absorption
capacity, solubility index, peak, trough, breakdown, final, and setback viscosities. The
pasting time ranged from 5.07 to 5.46 min and 5.15 to 5.43 min for varieties and particle
sizes respectively. Bulk density, angle of repose, lightness (l*), water, and oil absorption
capacity, swelling power, and solubility index of teff flours were significantly (P<0.05)
increased with decreasing particle size, while the redness (a*), yellowness (b*), and
chroma(c*) decreased as flour particle size decreased. However, there was no significant
(P>0.05) differences in oil absorption capacity and dispersibility, moisture, and mineral
content due to variety and particle size respectively. Cookies' sensory attributes were
significantly (P<0.05) affected by both the flour varieties and negatively correlated with
flour particle size. The cookie containing Bora flour fractions ranging from 90 to 160 μm
obtained the greatest score across all sensory attributes and it was best combination for
cookies.
