Study On The Milling And Eextrusion Technology Of Oats

The effect of heat-treatment on milling yield, nutrition compositions, viscosity properties of oats was explored, and the effect of extruder operation parameters on the qualities of oat extrudate was researched. The purpose of this research was to provide experiment data and technology support to develop the milling and extrudate of oats.Oats (Avena Sativa L.) samples were milled by a Chopin experiment mill type CD-2 into four streams, namely break flour(BF), midding flour(MF), fine bran(FB), and coarse bran(CB)after different heating treatment such as air-heating at 140℃,155℃,170℃respective or far-infrared heating at 200℃,220℃,240℃respective. The flour yield, the nutrition compositions, including protein, fat, and fiber contents of four streams and the viscosity properties of BF, MF and Oats Flour were investigated. The effect of extruder operation parameters (barrel temperature, material moisture and feed rate) on the system parameters (pressure and torque)of extruder, and product properties (specific volume, crispness, hardness, color, water absorption index, water solubility index, etc.) of extrudate was studied during the oat extrusion by orthogonal experiment method(L9(34)) with Oats Flour. A comprehensive evaluation of the extrudate was obtained by using factor analysis. The operation parameters of oats extrusion were opitimized and validated.Conclusion:(1)After heat-treatment, the milling yield of BF and MF of oats increased significantly. The total milling yield of four components was 18.18% higher than that of oats without heat-treatment. The protein decreased from CB, FB , MF, to BF. The fat of BF reduced significantly. The fiber of FB and CB raised significantly.(2)After heat-treatment, the average gelatinization temperature of BF, MF and Oats Flour were decreased significantly, which were lower than that of oatS without heat-treatment. Their peak viscosity; final viscosity and hold viscosity increased both under air-heating (140℃,155℃) and far-infrared heating (200℃), relative to non-treated samples. With the temperature of heat-treatment increasing gradually, their viscosity properties decreased. Their peak viscosity; final viscosity and hold viscosity at air-heating (170℃) and far-infrared heating (220℃) were lower than those at air-heating (140℃) and far-infrared heating (200℃).(3)The effect of qualities of extrudate of oats decreased from extrusion temperature, feed rate, to mass moisture. Under the laboratory condition, the optimal extrusion parameters of the test was as follow. The barrel temperature was 165℃. The mass moisture was 20%. The feed rate was 30g/min, and the screw speed was 120r/min. Validation experimentation showed that those operation parameters were stably and feasible.The result shows that heat-treatment has significant effect on the milling yield, nutrition properties, and viscosity properties of Oats Flour; nice extrudate of oats by technology design and optimization of extrustion could be produced.