Abstract: Based on the optimum basic recipe obtained from the nutritional breakfast cereals formula, and following the test design and data analysis according to response surface methodology, the relationship between extrusion main operation parameters (the screw speed, the feeding rate, the water feeding rate) and breakfast cereals bulk density was investigated. The product bulk density was seen as a vital quality parameter. The relationship among the product bulk density, water absorption and water solution Index has been studied. A mathematic model was built up to optimize the selection of the values of three kinds of operation parameters. These research results could be used to develop extruded breakfast cereals food and to study research working principles of twin-screw extruder to process cereals materials. At the meantime, these research results could be also used to quickly evaluate the quality of breakfast cereals.

Key words: breakfast cereals, twin-screw extrusion cooking, operation parameter, response surface methodology