Article history:
Received: December 9, 2016
Accepted: November 23, 2017

The present study was carried out to determine the effect of different proportions of red teff, wheat and okara on the physical, functional and sensory properties. The experiment was conducted in a D-optimal mixture design using Design Expert® and generated 16 runs with different proportions of three flours. The minimum and maximum values of red teff, wheat and okara were considered as 40-50%, 20-40% and 10-20% respectively. The functional, physical and sensory properties were determined for all the cookies as well as for the control sample (100% wheat) according to the standard methods. Statistically significant (p≤0.05) difference in bulk density was observed between red teff with okara. The water absorption capacity showed a highly significant difference (p≤0.01) in red teff with okara interaction. The highest hardness value (71 N) was recorded for cookies prepared from 40%, 10%, 50% of red teff, wheat and okara flour blends respectively, whereas the lowest value (23 N) was recorded for the control. The spread ratio of the cookies varied between 1.652 and 2.067. Okara concentrations affected the aroma and taste due to the beany flavour. The overall acceptability of cookies prepared from red teff, wheat and okara showed no significant difference (p≤0.05) in both linear and quadratic models and overall acceptability of the cookies from 100% wheat and blends was almost the same. In conclusion, the functional and physical properties of the cookies that are prepared with the different concentrations of okara, and teff blended cookies correspond to the levels shown by the control samples. In sensory analysis, overall acceptability of the cookies prepared with okara was similar to the control (only wheat). So, okara can be successfully used in the preparation of cookies.

Keywords:
D-optimal mixture design
okara
sensory properties
spread ratio
water absorption capacity