Evaluation the effect of whole oleaster and oat flours in breakfast cereals formulation

In recent years, the individuals' demand for consumption of healthy and useful products has increased. With regard to the specific role of breakfast cereal in today's dietary habit, the incorporation of nutrients into their formulation is considered as a way to produce functional food products. So in this research, the effect of extrusion variables containing feed formulation (whole oleaster flour to whole oat flour (10 to 90, 25 to 75 and 40 to 60%), feed moisture (14, 18 and 22%) and screw speed (120, 150 and 180 rpm) on some properties of snack was investigated. Thus, the central composite design was used to assess the water absorption index (WAI), water activity (aw), expansion ratio. Based on the obtained results, in a constant condition of other variables (feed moisture; 18% and screw speed; 150 rpm), an increase of the whole oleaster flour ratio from 10 to 40% decreased the WAI (from 5.64 to 5.16) and expansion ratio (from 1.72 to 1.48). While, an increase of the feed moisture from 14 to 18% led to an increase in the WAI (from 5.01 to 5.16) and water activity (from 0.33 to 0.63), when replacement level and screw speed were 25% and 150 rpm, respectively. The evaluation results of the screw speed in the moisture of 14 and 22% indicated that increasing the speed resulted in a decrease and increase in WAI, respectively. In addition, the relationship between the expansion ratio and microstructure was proved by scanning electron microscopy method. The optimum condition was found to the blends of whole oleaster flour/whole oat flour (10:90), screw rate of 180 rpm, and feed moisture content of 22% with desirable properties including (0.64%), expansion ratio(1.85), water absorption index(6.26).