Effect of intensity and time ultrasound on rheological properties of extracted ß_glucan of flour oat

β_glucan is dietry fibre and soluble gum and .it  has various physical properties such as thickening,stabilizing, emulsification, and gelation.in this study the effect of intensity (0,200, 300, 400watt) and time (0, 3.5  and 7minute sultrasonic waves were investigated on the physicochemical and the rheological properties of extracted.ß_glucan.The results showed that ultrasound intensity and time on moisture, ash, protein, starch and β-glucan content were significant (P <0.05), While it was not significant on fats and fibers (P >0.05), The sample with the intensity of 200 watts in 3.5 minutes showed the highest amount of β-glucan (77.1%) and the sample at 400 watts in 3.5 min with the lowest amount of ß-glucan (55.6%).Result showed that apparent viscosity decreased by increasing of the shear rate. All samples showed shear thinning behavior.The highest consistency coefficient, zero shear viscosity and lowest flow index was controlsample., and the lowest consistency coefficient and zero shear viscosity and the highest flow index was  in the sample with 400 W intensity for 3.5 min. The results obtained from fitting the data with different rheological models showed that the Herschel  andCarreau model was chosen for the best model. Linear region assign about 0.5 %using strain sweep test. Result of frequency sweep test showed first, by increasing the frequency of both the modulus of loss and storage , the storage modulus was reduced at high frequencies. The control sample was at low frequency G²>G, at high frequency G¢>G², Other examples were G¢>G².