We investigated the standardization of the conditions for roasting flour in an oven without using oil and fat, as an alternative method of making brown roux.
The results obtained were as follows:
1) The change of color of roux by roasting depended on the set temperature of the oven. The important factor was the control of roasting temperature and time.
2) The colors of roasted flour resembled those of soybean flour and rice bran. The objective indicator of the color difference between the roasted flour and the un-roasted one was ΔE: 31-36.
3) The sensory evaluation revealed that the recommendable conditions of roasted flour concerning the set temperature of the oven and the time of roasting were 180°C for 120 min,190°C for 60min and 200°C for 45min. Especially, the condition of 190°C for 60 min was the most desirable from the viewpoint of the quailty control and operational efficiency.
4) The diluted roasted roux (sauce) that was roasted for 5 min was definitely preferred to the one that was roasted for 120 min.
5) The apparent viscosity of each roasted flour was almost the same under the set temperature from 180°C to 200°C.
6) The taste of roasted flour was similar to that of brown roux.
