Method and apparatus for producing a puffed foodstuff

摘要

A method of processing a foodstuff raw material in particulate form is described as is apparatus for performing the method. Both method and apparatus involve preheating the particulate food material in a preheating chamber and then subjecting the preheated food material to heating by microwave energy in a main processing chamber. A helical screw conveyor is provided to convey the particulate matter through the preheating and main processing chambers. The pitch of the helical screw conveyor is wider where the conveyor passes through the main processing chamber than the pitch where the screw conveyor passes through the preheating chamber.