Low density edible animal chews and methods of making same

Abstract

Edible chews for pets have a low density (e.g. about 1.0 Kg/L or less) and a smooth exterior surface. One method by which the low density and the smooth exterior surface can be achieved uses a modified extrusion die to increase shear and restrict surface bubbles. Another method by which the low density and the smooth exterior surface can be achieved uses an extruder screw with a modified profile that holds a dough longer therein to create a whipping effect resulting in more bubble nucleation sites and hence a more uniform cellular matrix. The puffed (expanded) product was experimentally tested and provided better dental cleaning scores than a current unexpanded similarly formulated commercial dental product.

The invention is claimed as follows: 
     
         1 . An edible pet chew comprising an expanded pre-gelatinized cereal flour matrix and having a substantially smooth exterior surface and a density not greater than about 1.0 Kg/L. 
     
     
         2 . The edible pet chew of  claim 1  wherein the chew has a form of single unitary piece. 
     
     
         3 . The edible pet chew of  claim 1  wherein the chew does not contain a supercritical fluid. 
     
     
         4 . The edible pet chew of  claim 1  wherein the chew has a caloric density of 1.5-2.7 Kcal/cm 3 . 
     
     
         5 . The edible pet chew of  claim 1  wherein the density is at most about 0.9 Kg/L. 
     
     
         6 . The edible pet chew of  claim 1  wherein the chew comprises a body having a substantially cylindrical shape and comprises radial ridges extending from the body parallel to each other along at least a portion of the length of the body. 
     
     
         7 . A method of making an edible pet chew, the method comprising the steps of:
 preparing a dry mix comprising a pre-gelatinized cereal flour;   metering the dry mix into an extruder comprising an extrusion die;   adding a hydrogen bond-forming component to the dry mix to form a dough;   promoting nucleation of the dough by subjecting the dough to a combination of shear and a temperature in a section of the extruder adjacent to the extrusion die to form a heated and sheared dough, the temperature in the section adjacent to the extrusion die is higher than a temperature of at least one previous section of the extruder; and   directing the heated and sheared dough through an opening of the extrusion die comprising grooves, each of the grooves has an open end and a bottom surface opposite to the open end, and the width of the bottom surface is greater than the width of the open end.   
     
     
         8 . The method of  claim 7  wherein the grooves have a substantially triangular cross-section. 
     
     
         9 . The method of  claim 7  wherein the grooves have a width that continuously decreases as the grooves extend toward the center of the opening. 
     
     
         10 . The method of  claim 7  wherein the grooves are evenly spaced along an inner periphery of the opening of the extrusion die. 
     
     
         11 . The method of  claim 7  wherein the temperature in the section of the extruder adjacent to the extrusion die is at least 120° C. 
     
     
         12 . The method of  claim 7  wherein the hydrogen bond-forming component comprises a polyhydric solvent. 
     
     
         13 . A method of making an edible pet chew, the method comprising the steps of:
 forming a dry mix comprising a pre-gelatinized cereal flour and a bicarbonate;   metering the dry mix into an extruder comprising an extrusion die;   adding a hydrogen bond-forming component to the dry mix to form a dough; and   promoting nucleation of the dough by subjecting the dough to a combination of shear and a temperature in a section of the extruder adjacent to the extrusion die, the temperature in the section adjacent to the extrusion die is higher than a temperature of at least one previous section of the extruder to form a heated and sheared dough.   
     
     
         14 . The method of  claim 13  wherein the bicarbonate is sodium bicarbonate. 
     
     
         15 . The method of  claim 14  wherein the dry mix comprises 0.2 to 1.5 wt % of the sodium bicarbonate. 
     
     
         16 . A method of making an edible pet chew, the method comprising the steps of:
 forming a dry mix comprising a pre-gelatinized cereal flour;   metering the dry mix into an extruder comprising an extrusion die and a barrel comprising a vent and a vent-stuffer;   adding a hydrogen bond-forming component to the dry mix to form a dough;   using a reverse element of the extruder to extend a time spent by the dough in the barrel comprising the vent and the vent-stuffer;   using mixing elements in the barrel comprising the vent and the vent-stuffer to whip the dough and promote nucleation of the dough; and   promoting further nucleation of the dough by subjecting the dough to a combination of shear and temperature in a section of the extruder adjacent to the extrusion die to form a heated and sheared dough, the temperature in the section adjacent to the extrusion die is higher than a temperature of at least one previous section of the extruder.   
     
     
         17 . The method of  claim 16  comprising adding a bicarbonate to the dry mix. 
     
     
         18 . The method of  claim 16  comprising aerating the dough in the barrel comprising the vent and the vent-stuffer. 
     
     
         19 . The method of  claim 16  wherein the vent is configured to provide ambient pressure. 
     
     
         20 . An edible pet chew made by a process selected from the group consisting of the method of  claim 7 , the method of  claim 13 , and the method of  claim 16 . 
     
     
         21 . A pet treat comprising:
 an edible pet chew comprising an expanded pre-gelatinized cereal flour matrix and having a substantially smooth exterior surface and a density not greater than about 1.0 Kg/L; and   at least one filling comprising radial sides surrounded by the edible pet chew.   
     
     
         22 . A method of cleaning teeth of a pet, the method comprising administering to the pet an edible pet chew comprising an expanded pre-gelatinized cereal flour matrix and having a substantially smooth exterior surface and a density not greater than about 1.0 Kg/L.