Optimize Of Whole Oat Grain Extrusion

Extrusion is a mixed set of materials, mixing, crushing, heating, steaming, sterilization, expanded and molded. As one of the processing technology, extrusion is been widely used in food and feed processing industries. Thus, oat has high nutritional value and health functions. Nowadays, extrusion technology on oat is mainly concentrated in the effects of different material, different equipment and different technical parameters of extrusion products on flour at home and abroad. In this study, Baiyan2 Whole Oat Grain was extruded by using a Twin-screw extruder. And the regression model was established by response surface methodology by using factors including added volume, steaming time, and screw speed. The responses including expansion ratio, surface area, color, texture, sensory scores, fat and protein content of the extruded products were measured. Synthesis score was obtained by factor analysis. And combined synthesis score with response surface analysis, the optimum process parameters was obtained. Finally, the microscopic characteristics of extruded products was analysed. The conclusions were list as following:(1) Low fat oat grain (4.96%) was better for extrusion process than high fat (7.94%).(2) Compared with soaking for 6h, soaking for 2h and steaming 5-15 min of oat grain before extrusion can be more efficient to increase water content (40%) and the product is more smooth.(3) Compared with original oat flour, the flour of oat grain extrusion had unequal sizes and had sharp edges corners of polyhedral particles, like the secondary oat starch granule morphology. But its average size was bigger than oat starch. There was not adhesions between granules, probably because of the protein denaturation.(4) Adding 50% wheat starch and 50% corn starch is positive to the quality of product.(5) The whole grain oat has higher synthesis score. The score rose with the improve of screw speed and starch quantity. And the score increased at first and then decreased with the extend of steaming time. Combined synthesis score with equipment conditions, the optimum process parameters as follows:screw speed, steaming time and excipient adding amount were 300rpm,5min,20%, respectively.