assembly surface texturization of the protein sheet while it is still in the die assembly has been found to build in certain unique textural characteristics to the protein structure such as retort stability greater density and firmer bite identity surface texturization as used herein is accomplished by applying external heat to both surfaces of the thin protein sheet as it passes through the die assembly as the protein sheet passes through the die it should contact the heated die surfaces for a time sufficient to texturize the surfaces of the protein sheet the residence time in the die can be controlled by varying the product feed rate and or by increasing the length of the die assembly generally residence times of from about 0 3 minutes up to about 1 minute or more are satisfactory to achieve the requisite degree of surface texturization the preferred residence time is about 0 5 minutes the upper limit on die residence time should be less than the time at which thermal degradation begins the protein sheet formed in the die should be relatively thin to achieve the overall enhanced properties of the present invention satisfactory results have been achieved with sheet thickness of up to about 1 2 inch the preferred sheet thickness is about 3 16 inch the sheet thickness should not be so great as to have a significant adverse effect on the final product as used herein the term 34 sheet 34 is intended to include 1 a flat product with length and width dimensions much greater than its thickness like a sheet of paper and 2 a product in which a.