Processing apparatus for food materials

A pressure processing apparatus comprising:

• at least three pressure containers,
• a free piston provided within each pressure container, each said free piston being slidable in an axial direction of the container and dividing said container into one chamber and an other chamber,
• a pressure medium supply and discharge device connected in common to each said one chamber partitioned by said free piston, including a common pressure medium supply line, and branch lines connected to said one chamber, an opening and closing valve on each of said branch lines, a pressure medium discharging bypass line connected to each branch line between each of said opening and closing valves and said one chamber, and an opening and closing valve on each said bypass line, and
• a supply and recovery device for a liquid material to be processed, including a common supply line for the material to be processed, and branch lines connected to each other chamber and the supply common line of the supply device for said material to be processed, an opening and closing valve on each of said branch lines, a recovering bypass line connected to said recovery device in the branch line between each of said opening and closing valves and said other chamber, and an opening and closing valve provided on each bypass line.