Apparatus for co-extrusion of a dough mass with particulate matter in the outer dough

A co-extrusion apparatus for forming a composite food product having dissimilar inner and outer portions, wherein the inner portion is enveloped by the outer portion, and the outer portion is a dough which contains particles, comprising:

• an inner extrusion port having an exit orifice with a first cross-sectional area through which the inner portion is extruded;
• an outer extrusion port, including
• an exit orifice with a second cross-sectional area greater than said first cross-sectional area;
• means for substantially removing dough from the parts of the particles that penetrate the exterior surface of the outer dough portion, said removing means being positioned adjacent said exit orifice and within said outer extrusion port;
• and
• means for inducing turbulence in the outer dough portion, including
• a generally bevelled surface formed in said outer extrusion port the angle between said bevelled surface and said removing means being about 60.degree.;
• and
• a generally annular and sharp line of intersection between said bevelled surface and said removing means, whereby a tumbling motion is imparted to the particles carried within the outer dough portion for causing at least a portion of the particles to penetrate the exterior surface of the outer dough portion;
• wherein said inner extrusion port is recessed a distance d from said exit orifice of said outer extrusion port to define an exit passage between said inner extrusion port and said outer extrusion port, said distance d being sufficient to permit the particles carried in said outer dough portion to pass through said exit passage;
• first conduit means communicating with said inner extrusion port for providing the inner portion thereto;
• and
• second conduit means communicating with said outer extrusion port for providing the outer dough portion thereto, the outer dough portion enveloping the inner portion to form a composite food product having dissimilar inner and outer portions.