Abstract:
A method of producing an expanded product which resembles meat, directly from soybean meal itself, including the steps of utilizing soybean meal that has substantially all the fat removed to an amount of about 5% or less, and preferably 2% or less, moistening the soybean meal such as mixing the soybean meal with water to obtain a moisture content of about 20%-40% by weight, controlling the pH within the range of 5 to 12, preferably 6 to 9, preferably adding an edible pH altering electrolyte while maintaining the controlled pH, and then simultaneously, mechanically working, heating above 212° F., and pressurizing the moistened soybean meal in an extruder chamber sufficiently to cause continuous conversion of the meal to a flowable substance, and forcing the substance through and out of restricted orifice means to expand it into a lattice network structure having resilience, body strength, and appearance approaching that of meat.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of my copending application entitled PROTEIN PRODUCT AND METHOD AND APPARATUS FOR FORMING SAME, filed Dec. 9, 1966, Ser. No. 600,471, which in turn is a continuation-in-part of my application entitled PROTEIN PRODUCT, filed July 10, 1964, Ser. No. 381,853, both now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a method and apparatus for producing a meat-simulating product from protein-containing vegetable materials, particularly soybean meal, and to a meat-simulating product produced from protein-containing vegetable materials. 
     During recent years, extensive research and development efforts have been applied toward the development of meat-like or meat-simulating food materials prepared from protein-containing vegetable substances. As is known, the chief nutritional value of meat is due to its protein content. However, although meat is a most desirable source of protein, from the consideration of eating pleasure, the production of meat is actually relatively inefficient, in terms of feed input to food output. Furthermore, certain crops such as soybeans, provide inexpensive by-products which have a high percentage of potentially available protein, but which are not normally palatable and/or edible. 
     One excellent technique for producing meat-simulating edible foods from protein-containing vegetable materials such as soybean meal is taught in U.S. Pat. No. 2,682,466 to Boyer, entitled HIGH PROTEIN FOOD PRODUCT AND PROCESS FOR ITS PREPARATION, issued June 29, 1954. This technique involves the creation of a large number of small diameter spun fibers which are then gathered into bundles or &#34;tows&#34; and thence formed into various type edible products with subsequent operations. While these products are of high quality, the process is complex and expensive, so that the products must be priced in the general range of the corresponding actual meat products. Moreover, the product output per expense unit of equipment is relatively small. 
     Consequently, there has existed a definite need for a relatively inexpensive method of treating protein-containing vegetable materials to produce a product which would bear resemblance to actual meat in appearance, physical structure and texture, and chewing and mouth-feel characteristics, and that could be practiced sufficiently inexpensively that the product could be priced at a small fraction of the price of actual meat products. 
     It is a primary object of this invention, therefore, to provide a unique relatively inexpensive method of treating protein-containing vegetable materials to convert them from a generally unpalatable substance to a highly palatable and desirable product that is restructured to resemble meat in appearance, physical structure and texture, chewing characteristics, and nutritional value. Further, these properties and characteristics can be controllably varied quite readily by the method. 
     Another object of this invention is to provide a novel method of producing highly nutritional, highly palatable meat-simulating food products from protein-containing vegetable materials, particularly soybean meal, such that the method is capable of relatively high production, continuous product output per expense unit of equipment. Moreover, the amount of protein in the product can be greatly varied as desired. 
     Another object of this invention is to provide a novel method of producing from protein-containing vegetable material a meat-simulating product which can be rapidly and inexpensively dried as it is produced, to be capable of conventional packaging for extended unrefrigerated storage in its dry condition. Further, the stored product can be rapidly rehydrated in a matter of seconds, in a very simple manner, without cooking, heating, autoclaving, or steaming, but rather merely by the addition of aqueous liquid. 
     Another object of this invention is to provide a novel highly palatable, highly nutritional meat-simulating food product from protein-containing vegetable materials, particularly soybean meal, capable of being dried, packaged, shipped, and stored for substantial periods, without refrigeration, and capable of rehydrating in moments merely by the addition of moisture, and without requiring cooking, autoclaving or pressurizing. 
     Another object of this invention is to provide, from a protein-containing vegetable material, particularly soybean meal, a meat-simulating food which has a fibrous lace network structure appearing and acting somewhat like the muscle fibers in actual meat, but which product costs only a fraction of that of meat. 
     Another object of this invention is to provide from protein-containing non-meat material, a meat-simulating product capable of inexpensive and rapid dehydration, and of subsequent simple and rapid rehydration, to effect a meat-simulating foodstuff having all the beneficial characteristics of meat but at a cost of about one-fifth of that of meat. 
     Another object of this invention is to provide novel extrusion apparatus capable of continuously, rapidly, and reliably converting protein-containing vegetable material, particularly soybean meal, into a restructured, excellent quality, meat-simulating product having a fibrous network structure resembling the muscle fiber structure of meat. 
     These and several other objects of this invention will become apparent upon studying the following specification in conjunction with the drawing. 
    
    
     DESCRIPTION OF DRAWING 
     The drawing is a side elevational, sectional view of the basic extrusion apparatus preferred for practicing the invention. 
    
    
     DETAILED DESCRIPTION 
     The concept of this invention pertains broadly to a unique processing treatment of protein-containing products to obtain a meat-like food material, the concept being intended for the treatment of protein-containing vegetable materials, with by far the most beneficial results being achieved when the novel concept is applied to soybean meal, in contrast to other vegetable protein materials such as peanut meal, corn meal, and cottonseed meal. In fact, by properly treating soybean meal according to this invention, a top grade, expanded product containing a fibrous network simulating the texture of meat tissues is obtained. 
     Soybean meal is the product resulting after oil is extracted from comminuted soybeans and is commonly called defatted soybean flakes. Soybean meal usually is in a flake-type particulate form. It could, however, be ground into a finer form such as powder. These various physical sizes and forms are broadly considered with the term soybean meal. In order to practice the present invention, it is important that the oil be extracted by chemical solvent techniques, such as with hexane rather than by mechanical pressing techniques, because the meal fed to the extruder in this process should be substantially free of oil. If mechanical pressing techniques are employed, the chemical solvent technique is subsequently employed before proceeding with the practice of this invention. 
     Specifically, it has been found that if the soybean meal is substantially free of residual oil, for example about 0.5% or less by weight, very excellent meat-simulating, fibrous formation occurs during extrusion, as well as the product exhibiting a controlled and excellent rate of expansion as ejected from the extruder. If the residual oil content in the soybean meal is present in a minor amount, e.g., about 2% by weight or less, a usable product can be obtained by the novel process, since some limited fibrous structure forms, but the fibrous structure is poor in comparison with that from substantially oil-free soybean meal. Furthermore, if the residual oil content is much above the minor amount, for example, about 5% by weight of the soybean meal, very little or no fibrous formation occurs. No other vegetable oil or animal oil or fats should be added to the soybean meal prior to extrusion. Either of the terms &#34;oil&#34; or &#34;fat&#34; are used herein to encompass what might be considered as vegetable oils and fats, or animal oil and fats, whether liquid or solid in form. 
     Another important criterion, which has been determined for the soybean meal composition, is the carbohydrate content. This component has an effect on the amount of product expansion. In this regard, it should be noted that, for an optimum meat-simulating product to be formed, the product must have an interconnected fibrous lace network formation that appears, feels, and acts in some respects like muscular meat fibers. For this to occur, the product should be controllably expanded or puffed when ejected from the extruder. However, the expansion is limited so that it is not unduly puffed. This excessive puffing destroys or at least seriously limits the formation of the interlaced nature of the fibrous product. Regarding this factor, it has been experimentally determined that the carbohydrate content, if present in an amount over a certain minimum, increases the amount of expansion of puffing sufficiently that the fibrous structure is at least partially or completely broken up and destroyed. Specifically, the natural carbohydrate content of about 35% by weight should not be increased by any more than about 5% by weight added carbohydrate. For example, if the carbohydrate content is increased by about 15% by weight added carbohydrate, fibrous formation is normally prevented or destroyed. 
     Prior to being fed into the extruder, the soybean meal is mixed with a predetermined amount of aqueous liquid, such as plain water, in order to effect a necessary mininum moisture content. The soybean meal and moisture are mixed into a generally homogeneous mass prior to being fed through the extruder. The moisture content can generally vary between the minimum of about 20% by weight of the total mixture to a maximum of about 40% by weight of the total mixture. If the moisture content is varied within this range from the low amount to the high amount, the temperature of the mixture in the meal should be varied as specifically explained below. This moisture assists in the chemical changes that occur in the extruder, is essential to the controlled expansion of the product leaving the extruder, and probably has other functions which are not fully understood. Preferably, the moisture content is between 30%-40% if the sodium hydroxide is not added as explained hereinafter. If it is added, the preferred moisture content is 23%-34%. At any rate, the moisture is an essential component in the soybean meal mixture. 
     Associated with the moisture addition is the control of the pH of the soybean meal. Control of this pH is also significant in this process. The normal pH of soybean meal after oil extraction is usually within the range of 6 to 7, typically 6.9 or so. Although experimentation has shown that soybean meal of widely varying pH can be beneficially extruded according to this process, it has been determined that the resulting product varies greatly in characteristics and qualilty with variation in pH. Specifically, it has been determined experimentally that is is preferably to have the meal just slightly acidic or slightly basic. That is, it is broadly desirable to keep the pH within the broad range of 5 to 12 since, below 5 and above 12, very poor fibrous formation occurs. Of this broad range, it preferably should be kept within a pH range of 6 to 9. Experimentation over an extended period of time shows that the best fibrous formation occurs when the meal is slightly basic, within a pH range of 7.5 to 8.7. 
     Control of this pH is achieved by adding a common acid such as hydrochloric acid, phosphoric acid, a base such as sodium hydroxide or other common edible electrolytes, to the aqueous liquid prior to mixing this aqueous liquid with the soybean meal to form the moist mixture. The above-noted experimentation clearly shows that the addition of an hydroxide is particularly beneficial since it apparently has a function in addition to acting as a pH control material. The amount of sodium hydroxide added should be sufficient to raise the pH to about 8.2-8.7, with 8.6 being optimum. It appears to have a beneficial chemical action on the complex protein molecular structure to catalyze the reaction. Whatever the technical explanation, the addition of sodium hydroxide causes a substantially better grade of fibrous formation in the resulting extruded product, and greatly eases control of the process. It further enables the protein content to be varied within a wider range without preventing excellent fibrous formation, as explained hereinafter. If the mixture formed from the aqueous solution of sodium hydroxide and the soybean meal is allowed to set and &#34;cure&#34; for several minutes prior to introduction to the extruder, these beneficial results are even further assured. Hence, control of the pH of the mixture, particularly with hydroxyl ions, is very significant to obtain a top quality product. 
     Another controlling factor, in addition to the fat content, carbohydrate content, moisture content, and pH of the soybean meal, is the protein content of the composition. Typically, soybean meal resulting from conventional oil extraction processes has a protein content of about 44% or 50% by weight, depending on the degree of refinement. Normally, a protein content of less than about 44% is not encountered, although this process is intended to encompass vegetable materials having a protein content less than this. A typical protein concentrate which can be added to increase the protein is commercially termed &#34;isolated protein&#34;. Experimentation with this process shows that a soybean meal with a protein content of about 50% by weight produces the most desirable product, with optimum fibrous network formation and optimum expansion. Hence, preferably the operation is conducted on this material. However, the method does produce some fibrous formation in soybean meals having a protein content of about 30%, but below this value, the product is not very worthwhile. Furthermore, the protein content can be increased substantially about 50%, up to about 75%. Above this, the resulting product tends to have a gummy characteristic which is not desirable. Hence, preferably the protein content in the soybean meal should be between about 30% and 75% by weight, with the preferred amount being about 50% by weight. 
     The addition of a hydroxide, preferably sodium hydroxide, has a definite effect on the usable range of protein concentration which can be employed while operating with a minimum of production problems and producing a highly desirable product. 
     When a soybean mixture having the characteristics described above has been prepared, it is fed into an extruder assembly where it is subjected to elevated temperature and pressure and the extruder, as illustrated, is equipped with a restrainer plate 7. The rotating screw 5, in combination with this restrainer plate with its restricted outlet 11, creates a high pressure on the material in the extruder. The particulate, moist meal fed in changes form until it finally flows in a generally fluid manner even squeezing around the outer periphery of the screw in a recirculating fashion, to cause a severe mechanical working of the substance. The pressures in the extruder are elevated to several hundred psi, and normally fall within the range of about 300-600 psig. Part of the pressure is caused by the screw and restrainer plate. Part of the pressure is due to the high temperatures which result both from friction between the flowing product and components of the extruder, and from heat that is purposely added to the outside of the extruder in normal operation. This added heat is preferably obtained by passing steam through the forward or front annular jacket 15 within the extruder housing, around, but separated from, the forward end of the extruder chamber. The amount of steam heat applied is controlled by typical valving techniques in a manner to obtain temperatures which are not sufficiently high as to cause the product to scorch or burn, but which are sufficiently high to cause the desired chemical and physical reactions within the material. The amount of added heat to do this will vary with the particular extruder construction, but can be readily determined by trial and error during the initial stages of operation of the equipment. 
     The temperatures reached by the material in the extruder must be above 212° F. and actually should be considerably higher, within a certain specific range in order for a meat-simulating product with good fibrous structure to be formed. This varies with variations of the other mixture characteristics of which the most significant is moisture content. As the moisture content increases from about 20% to about 40%, the temperature may be decreased from about 310° F. to about 270° F. Below about 270° F., fibrous formation is poor. The preferred temperature range is about 270°-300° F., with optimum results having been obtained at about 280° F. 
     In addition to the steam jacket for adding heat, an annular cooling jacket 13 surrounds the rear portion of the extruder chamber. This has been found desirable in normal operation to maintain lower temperatures in the initial stages of mechanical working in the extruder. Cooling prevents the product from overheating to become scorched before it exits from the extruder. Again, the amount of cooling water and the temperature to cause the desired cooling effect will vary, but can be readily determined by trial and error during initial stages of operation. 
     The product outlet means from the extruder also includes a smaller secondary chamber into which the material discharges from orifice 11. The output from this second smaller chamber is also restricted by a die nozzle outlet 19. It has an area smaller than or about that of the restrainer or restrictor outlet 11. Without this two-stage restriction set up, it is extremely difficult to obtain acceptable fibrous formation in the product. In fact, another feature of the extruder has been found to be important to top quality fibrous formation when employing the cooperative makeup explained previously. This feature is the positioning of an elongated pipe member 17 between restrictor outlet 11 and die outlet 19. It has a diameter substantially smaller than the diameter of the extruder chamber to which it is attached, such diameter ratios normally being about 1/6 to 1/10.  The product is longitudinally passed through this member while still radially restricted, along the length of the tube, under high pressures and at the elevated temperatures prior to being ejected into the lower pressure and temperature of the atmosphere. The tube has a length of about 8 to 12 times its internal diameter. In actual dimensions, a representative example of these components would include an extruder chamber diameter of about 5 inches, with a length of 3 to 4 feet or so, and a tube diameter of 3/4 of an inch and length of about 6 inches. 
     The exact scientific explanation of the functions of this hollow pressure tube into which the material is ejected prior to ejection to the atmosphere, cannot be given; but the efficacy of it is very definite and significant. In fact, with some soybean meals where the protein content is low, only very poor fibrous formation occurs unless this tube extension is employed. 
     OPERATION 
     In operation, the soybean meal obtained by solvent extraction of oil from the soybeans is checked so that it has only a minor oil content, i.e., less than about 2%, and preferably is substantially oilfree, i.e., less than about 0.5% by weight of the meal. If the content is greater than this, the soybean meal must be treated with a chemical solvent such as hexane to extract the excess oil. Further, no other oil or fat material, animal or vegetable, is added to the meal prior to extrusion. 
     If desired, the meal may be ground more finely than the small flakes in which it normally occurs from the extraction process, but experimentation along this line indicates that this is not necessary. 
     Moisture is then added to the soybean meal, normally in the form of water, to bring the moisture content within the range of 20% to 40% by weight of the resulting mixture. The moisture and meal are mixed into a homogeneous mixture. 
     If the pH of the meal is to be adjusted, for example, to place it in the preferred range of 7.5 to 8.7, it is adjusted by adding the noted type of reagents, preferably. A basic material containing hydroxyl ions, preferably sodium hydroxide can be added by adding it to the water prior to moistening the meal. Enough is preferably added to bring the pH to about 8.6. If it is desired to adjust the pH into the acidic range, acid is added to the water and thus to the meal in the same fashion. 
     When the mixture is prepared and ready for the extrusion operation, it is fed into inlet 3 while the extruder screw 5 is rotated at a substantial speed, for example of about 150 rpm. During this operation, steam is passed through forward jacket 15, and normally, cooling water is passed through rear jacket 13. The meal mixture is advanced in the extruder by the screw while its temperature is increased to within the range of 270°-310° F. by the steam heat added, by the mechanical working friction, and possibly by the chemical changes occuring. Since the screw tends to advance the material faster than it can be passed through the restricted outlet means, the pressure builds up in the chamber to several hundred pounds per square inch, usually about 300-600 psi, while the product is severely mechanically worked in the extruder. By the time the mixture reaches the restrictor plate, it is in the form of a flowable substance which is forced from the main extrusion chamber, after a retention time of usually 30-40 seconds, through restrictor plate outlet 11 into the supplemental chamber. The material remains under elevated pressures and temperatures as it is advanced by pressure differential through the secondary chamber through the elongated tube, to die outlet means 19. As it emerges from outlet 19 under the high internal pressures into the much lower atmospheric pressure, the super heated moisture paritally flashes off by evaporation to cause product expansion and partial cooling. If the product is being processed properly, it emerges in the form of a continuous, elongated, expanded, fibrous member which is restructured and which can be kept in its continuous form or severed into individual chunks as it emerges by any ordinary cut-off means. The expanded product is very porous, and has a fibrous network or lace structure which somewhat resembles that of actual meat tissue fibers. If the product is kept moist in its freshly extruded condition, it can be directly used for simulated meat. Normally, it is desirable to add coloring materials to the product before extrusion, and to add flavorings before or after extrusion. The product is very nutritious as it emerges, is sterile, palatable, and wholesome. If portions of the product are pulled apart with one&#39;s fingers, the texture appears and acts somewhat like that of meat. 
     Instead of storing the product in its moist condition, wherein it should be kept under refrigeration or in hermetically sealed condition, it can be easily and quickly dried merely by passing it through a conventional drying chamber so that it can be packed and stored in a more convenient fashion. Its porosity enables it to dry quickly enabling simple and direct packaging in its dried form in a manner similar to cereal products. An important feature of this product is that it can be completely rehydrated extremely rapidly, i.e., in a few seconds, with great ease, i.e., merely by adding an aqueous liquid. Thus, whenever it is to be eaten, the dried chunks are rehydrated by mixing with aqueous liquid such as pure water, which is preferably warm so that it would be at a desirable eating temperature. The rehydrated product exhibits all of the desirable noted meat-simulating characteristics. No cooking, autoclaving, or pressurizing is necessary for rehydration. 
     The resulting product can be used for human food, e.g., &#34;health foods&#34;, or, due to its cost being only about 1/5 or less of that of conventional meat, it can be economically used for pet foods. Palatability and nutrition tests have proven it to be an excellent and desirable food for pets or other animals. The material can be employed in a variety of forms, can be colored and/or flavored in a variety of fashions, and can be controllably varied in characteristics, to resemble various types of meat materials. By controlling the rate of feed of the product through the extruder, temperatures, degree of expansion, additives, protein content, moisture content, and the like, the character of the product can be widely varied while retaining its fibrous meat-simulating texture. The possibilities of this food product are many. 
     To assure that one having ordinary skill in the art will understand this invention, the following detailed illustrations are provided. It will be realized that literally thousands of various experimental runs have been made after discovery of the basic invention involved, over an extensive period of time. These were done in order to determine the critical limitations of the composition and method steps, and the operational criteria. To record the data of all of these runs here would unduly lengthen this document and would serve no good purpose. 
     ILLUSTRATION 1 
     Seventeen pounds of soybean meal, after oil extraction by hexane were employed. It had a protein content of 50% by weight of the soybean meal, and a fat content of 0.5% by weight. This soybean meal was mixed with 2600 cc. of water, having sufficient sodium hydroxide added to the water to cause the mixture of moisture and soybean meal to have a final pH of 7.5. The mixture was allowed to set and cure for 5 minutes to obtain a good water and sodium hydroxide dispersion, penetration, and reaction. The mixture was then fed into the extrusion device illustrated, with steam being supplied to jacket 15 at a pressure of 20 psig and cooling water at room temperature being constantly passed through jacket 13. The opening in restraining plate 7 was 1/4 inch in diameter, with screw 5 being rotated at 150 rpm. The mixture was thus mechanically worked within the extruder at a temperature of around 300° F., with the pressures varying somewhat but being generally above 300 psig. The material was continuously passed through the extruder, passing through the elongated tube and out an extruder nozzle having a size of 3/8 × 1/8 inch. The reaction time of the material within the extruder was about 30 seconds. The mixture was ejected from the nozzle in a continuous stream, and was a coherent fibrous structure which expanded with passage through the nozzle, to form a porous structure. The product, when removed, had a fibrous meat-like texture of excellent quality. 
     ILLUSTRATION 2 
     Another run similar to Illustration No. 1 was made, but in this instance the pH was adjusted to the acidic side with hydrochloric acid with the soybean meal being mixed with 1,000 cc. of water to which 15.5 grams of concentrated hydrochloric acid had been dissolved. The materials were mixed for approximately 13 minutes, and then an additional 1,850 cc. of water were added, with the resulting pH of the mixture being approximately 6.6. The mixture was then fed to the extruder, and passed through the extruder at pressures generally of about 400 psig and at a temperature of about 300° F. The resulting product had good fibrous formation, but inferior to the fibrous formation of Illustration No. 1, when the pH was on the basic side. 
     ILLUSTRATION 3 
     This operation was just like that in Illustration No. 1 above, except that the moisture content was about 25% and the pH was not adjusted. The product was completely acceptable, and the fibrous formation was good but not as good as when the pH was above 7. 
     ILLUSTRATION 4 
     The meal was substantially the same as that used in Illustration No. 2, but the pH was adjusted in the mixture to 5.5 by adding 52 grams of hydrochloric acid in solution in 2,300 cc. of water. Although fibrous portions did form, they did not bind the product together in the effective manner of previous runs, and fibrous formation was less than previously. In additional experiments, it appeared that the rate of fibrous formation tended to fall off quite rapidly as the pH is lowered below this amount. 
     ILLUSTRATION 5 
     In this illustrative run, the soybean meal was of the type described in Illustration No. 1. The mixture, however, was formed by adding 50 grams of sodium hydroxide and approximately 1,000 cc. of water were mixed with the soybean meal to obtain a resulting mixture pH of 8.6, after 1,300 cc. of additional water was subsequently added. The product was then extruded through the equipment illustrated, with the ultimate product exhibiting very substantial puffingg puffing but yet with complete coherence by reason of the fibrous network, and with excellent meat-simulating characteristics. It dried quickly and easily at temperatures above 212° F. to evaporate excess moisture. It rehydrated within a few seconds merely by adding warm water. 
     ILLUSTRATION 6 
     Parallel runs were made on soybean meals containing approximately 2% soybean oil, 2% animal fat, and 5% soybean oil in the meal. Seventeen pounds of the 50% protein soybean meal was mixed with 2,300 cc. of water in each instance and 7.5 grams of sodium hydroxide to bring the pH within the range of just above 7, but under 8.The meal was then extruded through the equipment as previously, with the result being that the product from the meal containing 2% soybean oil and the product from the meal containing the 2% animal fat exhibited some fibrous formation but of a generally poorer quality, while that containing the 5% soybean oil exhibited no fibrous formation at all. In fact, in this latter instance, the particulate meal was discharged in much the same form in which it went into the extruder. 
     ILLUSTRATION 7 
     Parallel runs were made on the 50% protein soybean meal containing 5% carbohydrate and 15% carbohydrate in the form of corn starch. The resulting products included a product of the 5% mixture which had poor fibrous formation, with excessive puffing breaking up the fibrous network and the 15% product having only puffing with no fibrous formation occurring so that it did not have meat-simulating characteristics. 
     ILLUSTRATION 8 
     Parallel experiments employing protein contents of 44% and below, run at various pH levels, at varying extruder temperatures and pressures exhibited differing types of fibrous formation. Experiments with and without the extruder tube extension were made. 
     As stated previously, the number of illustrations could be endlessly listed, but it is believed that, with the above illustrations and discussion of the criteria and critical factors involved, anyone having ordinary skill in this art could adapt the novel method and apparatus to various situations to obtain the desired type of product merely by a few trial-and-error variations in the moisture content, pH, fat or oil content, carbohydrate content, extrusion pressures and temperatures, restrainer plate restrictions, extrusion die nozzle sizes, and the like. In fact, it is realized that variations in these and related factors could be readily made within the concept taught herein. Hence, the invention is intended to be limited only by the scope of the appended claims and the reasonably equivalent methods, apparatuses, and products to those defined therein.