Abstract: A method of preparing a protein food product having an arrangement of helically aligned protein layers is disclosed wherein an aqueous slurry of a proteinaceous material is frozen by conveying said slurry through an extruder equipped to provide a freezing zone in order to form ice crystal layers in said slurry which mold the protein material of the slurry into striated layers arranged in the form of a helix. The frozen extruded product is then heat set at a temperature sufficiently high to allow the protein layers to heat set and melt the ice crystal layers to form a protein food product. The resultant product has an improved degree of toughness because of "cross structuring" of the protein layers which is an inherent effect of the helix arrangement of the protein layers in the product.