| 摘要 |
Quick cooking rice products are manufactured in a low mechanical shear extrusion process by first pre-cooking a rice and water mixture in a preconditioner and then advancing the mixture along the length of an extruder sequentially presenting a cooking zone, a venting zone, a forming zone, and finally an extrusion die to yield an extruded product. Venting of gaseous products removes a significant amount of moisture from the mixture during the time that the latter passes between the cooking zone and the forming zone, and consequently the moisture content of the mixture within the cooking zone can be increased in order to reduce the total mechanical shear imposed on the mixture during the cooking process. The extruded product, once dried, closely resembles rice grain and readily rehydrates without exhibiting slimy or sticky characteristics, and has an increased tolerance to overcooking. A venting device has a rotatable screw for enabling gaseous materials to be discharged from the mixture while substantially preventing the escape of the mixture from the extruder barrel of the extruder. |
