EP3893659A1

EP3893659A1 - Modifying crisp texture based on the effects of alkalis and non-chemically reactive gas

Info

Publication number: EP3893659A1
Application number: EP19828628.8A
Authority: EP
Inventors: Justin BANACH; Jim KLEIN; Craig Air
Original assignee: Erie Europe
Current assignee: Erie Europe
Priority date: 2018-12-12
Filing date: 2019-12-12
Publication date: 2021-10-20
Also published as: WO2020120684A1; AU2019398757A1

Abstract

A method for modifying a texture of a protein product, said method comprising the steps of: a. Creating in an extruder a mixture including protein materials, alkalis, non-chemically reactive gas and water, (the word "including" is not limitative, which means that also other materials can be present in the mixture) b. introducing said mixture through a die engaged with said extruder, c. forcing the mixture though the opening of the die under pressure, d. allowing expansion of the mixture under atmospheric pressure; e. removing moisture from the expanded mixture to form the protein product.

Description

MODIFYING CRISP TEXTURE BASED ON THE EFFECTS OF ALKALIS AND NON- CHEMICALLY REACTIVE GAS

Background

The present invention relates to a method for modifying crisp texture of protein food. Consumer’s demand for « ready to eat and portable protein » options continues to strengthen. Up to now, the protein is typically consumed in the form of a shake, which was made using a powdered protein mixed with water and or milk/juice. This trend still continues today and more recently, various types of protein bars have become popular. But shakes and bars do not give the consumer an“eating/chewing” experience like a snack food.

With the advent and growth of protein supplemented products, several crisps were developed over the years which combined a variety of ingredients including dairy and vegetable proteins as well as fibers, flavors, starches, sugars, and other components. These crisps have relatively low protein concentration. These lower protein crisps also need a practical method to modify the crisp texture.

State of the art

The patent US 9723859 describes a method for producing a high protein food by mixing casein, whey protein, alkalis and water. The protein content of the end product may be approximately 90-95% on a dry weight basis. However, it is difficult to control the texture in the fabrication method.

Disclosure of the invention

The texture of crisp is critical to ensure a positive eating experience, which requires the product to have integrity and some strength to stay together prior to consumption and the ability to crunch, hydrate, and breakdown into a swallowable mass during mastication. These conditions allow the user to bite down and to experience the crunch that is typically desired in a snack product.

Applicant discovered during its research that the porosity of a crisp can correlate strongly with its texture and with the texture in the final application. In traditional expanded snack products, only the flashing off of steam after extruding material from the die generates porosity. The expansion occurs at the extruder die, more specifically, the expansion occurs as water flashes to steam associated with high pressure drop upon leaving the die. Alkalis are introduced to have an influence on crisp texture by changing extrudate porosity, average air cell size, average cell wall thickness, and increase pH, which assists with hydration while chewing, and hence its overall texture. Alkalis may either serve as nucleating agents, generating regions conducive for air cell development, or breakdown into non-chemically reactive gaseous compounds such as carbon dioxide.

In order to solve the above-mentioned technical problems, the present invention discloses a method for modifying the texture of protein products by introducing non-chemically reactive gas to modify the crisp porosity.

More particularly, the present application concerns a method for modifying a texture of a protein product, said method comprising the steps of:

a. Creating in or prior to an extruder a mixture including protein materials, alkalis, non-chemically reactive gas and water,

(the word“including” is not limitative, which means that also other materials can be present in the mixture)

b. introducing said mixture through a die engaged with said extruder, c. forcing the mixture though the opening of the die under pressure, d. allowing expansion of the mixture under atmospheric pressure;

e. removing moisture from the expanded mixture to form the protein product. According to other advantageous and non-limiting features of the invention, the following characteristics can be taken alone or in any technically feasible combination:

- the non-chemically reactive gas is introduced into the extruder through a gas injection system, which contains a compressed gas bottle and a series of valves;

- within the injection system, the gas pressure at upstream of the injection system is greater than the gas pressure at the injection point to the extruder;

- within the extruder, the gas pressure profile depends on the geometrical configuration of the extruder and of the die;

- the non-chemically reactive gas is introduced in its solid phase into the extruder via a feeder;

- alkalis, non-chemically reactive gas and the protein materials are added together;

- alkalis and/or non-chemically reactive gas are/is added separately from the protein materials;

- the non-chemically reactive gas is carbon dioxide, nitrogen, or any other compressed gas sources;

- a high protein product is obtained, containing at least 70% crude protein on dry-basis;

- a lower protein product is obtained, containing less than 70% crude protein on dry- basis,

- the temperature at the extruder is between 4°C and 121 °C degrees;

- the injection pressures range from 15 pound-force per square inch (psig) to the critical pressure of the non-chemically reactive gas at ambient temperatures, the protein product has a bulk density from 40 to 350 g/L.

Figures

Other advantages and characteristics will become apparent on examination of the detailed description of embodiments, which are in no way limitative, and of the attached diagrams, in which:

[Fig.1 ] is a schematic configuration of the system that implements the method for modifying crisp texture;

[Fig.2a] and

[Fig.2b] shows respectively the external and the cross-section features of a kind of fabricated crisp;

[Fig.3] shows the adding sequence.

To simplify the description, the same references are used for identical elements or elements providing the same function in various figures. The examples are given for illustrative but not limitative purpose for those skilled in the art to realize the invention. But other components, which are suitable for achieving the same effect, can also be used.

The method according to the invention can modify the crisp texture of different kinds of protein foods. Usually, the high protein product is defined as having a total crude protein concentration greater than 70% on a dry-basis, while the low protein product is defined as having less than 70% crude protein on a dry-basis. One example of high protein product is « Milk Protein Isolate » (MPI), which is a concentrated form of dairy protein in the nutritional industry consisting of two main proteins, i.e., whey and casein, with 65% to 85% by weight of a casein protein and with 15% to 35% by weight of a whey protein.

Typically, MPI protein concentration would be 85% or more on a dry-basis; some in the industry even specify it as being 89% protein dry-basis or more. The MPI is low in carbohydrates (i.e., < 3.7%) and low in fats (i.e., < 3.4%), which are critical issues for many health conscious and dieting consumers. When MPI is used as a starting base material, carbohydrates such as sweeteners, and fats such as oils required in savory applications, can easily be added without deviating from overall nutritional quality. In addition, the simple and clean MPI label represents a significant benefit for manufacturing products, where labelling and ingredient sensitivity are critical. Other mid-level protein crisps are typically having anywhere from 3-7 ingredients in them. For the following paragraphs, the high protein product MPI is used as an illustrative but not limitative example to explain the method for modifying the crisp texture.

The figure 1 illustrates the schematic configuration of the system to implement the method for modifying crisp texture of protein food. The central part of the system is an extruder (1 ). It is contemplated that in an aspect of the method, the extruder may be configured as a twin- screw co-rotating extruder, which is an efficient means of processing raw materials in a way that produces an expanded/texturized protein crisp. But the extruder may be differently configured in other aspects without limitation. The temperature at the extruder can vary between 4°C and 121 °C degrees according to different crisp texture requirements.

The extruder is connected with at least one feeder (2), a water tank (3), a gas injection system (4) and a die (5).

In one embodiment, the extruder (1 ) is applied with only one feeder (21 ). In this embodiment, the crude materials are introduced to the extruder by the same feeder. The crude materials can be mixed either outside before being introduced to the extruder, or inside the extruder.

In another embodiment, the extruder (1 ) is applied with a plurality of feeders (21 , 22). Each crude material is filled in a separate feeder and is introduced to the extruder separately.

The crude materials like the protein materials, alkalis, and other processing aids, e.g. calcium carbonate (CaC03), can be mixed and/or blended using any suitable method and/or structure, including but not limited to blending tanks, mixers, conveyors.

The water tank (3) is connected to the extruder for applying water, which may be filtered and/or purified before it enters the extruder or tank. The alkalis can be dissolved in the water to adjust the pH value.

The gas injection system provides non-chemically reactive gas, e.g. carbon dioxide, nitrogen, etc., into the extruder. Within the gas injection system, the gas pressure upstream of the injection system is greater than the gas pressure at the extruder injection point. Within the extruder, the gas pressure profile depends on the screw configuration and on the die geometry.

The non-chemically reactive gas injection system is comprised of a compressed gas bottle, regulator valve, mass or volumetric flow meter, divert valve, check valve, and of an injector which introduces compressed gas into the extruder. Gas pressures, controlled by the regulator, will be in the sub-critical range such that the gas phase is maintained. The mass flow meter will indicate the rate of gas incorporation into the melted MPI within the extruder. Melted MPI is simply a MPI whereby the extruder has applied enough thermo-mechanical energy to collapse particulate structure such that resultant material exhibits viscoelastic properties. The divert valve allows for gas flow to be exhausted to the room prior to startup or shutdown. The check valve ensures that materials flow into the extruder and that melted MPI does not travel into the gas injector. That is, gas pressure upstream the check valve must always be greater than pressure downstream the check valve. Appropriate screw geometry (e.g., mixing elements) will help to uniformly incorporate the gas into the melted MPI. Upon reaching the die, pressure will build and then drop back to atmospheric pressure as material protrudes. This dramatic pressure drop will allow for the rapid expansion of entrained gases, including the injected non-chemically reactive gas as well as any entrained water vapor. The set points of the valves are p re-determined and only minor adjustments are carried out for the real-time adjustment while processing.

Another way to introduce the non-chemically reactive gas is using its solid phase through the feeder. Solid phase carbon dioxide is also called dry ice, which can be introduced into extruder barrel 1 via feeder 21 or feeder 22, separately or in combination with the protein and/or alkali powders. Depending on the temperature-pressure relationships developed through external heaters, viscous dissipation, and screw geometry, the solid dry ice will change to gas directly or will briefly enter the liquid phase, provided critical temperature has not been exceeded, before quickly changing to gas phase. Such non-chemically reactive gases will uniformly dissolve in the melted MPI to build pressure at the die. As the melted MPI is forced through the openings of the die, the pressure drops to atmospheric level allowing for rapid expansion.

The following paragraphs explain in detail the effects of alkalis and non-chemically reactive gases.

In the crisp formulation, the general geometry of the die provides the basic form of an expanded snack. The addition of alkalis and additional non-chemically reactive gases, added either through alkali addition or separately, gives additional flexibilities in manipulating and controlling the product’s finished texture, color, contour by different expansion ratios. Much as it does in helping a bakery product with texture, the alkalis help with creating stabilized and consistent“bubbles” in the melted MPI through nucleation and release of gas upon heating and chemical reaction in an acid environment. Additionally, alkali addition helps adjust melted MPI viscosity so that the MPI can better entrain gas within the extruder and yet remain viscous enough to resist complete collapse upon exiting the die. Adding non- chemically reactive gas into the extruder without dramatically influencing viscosity allows for easier management of gas entrapment than simply relying on alkalis or steam generation. In several alkalis including sodium bicarbonate and potassium bicarbonate, there is C02 that can be given off in situ when the alkali is hydrated, chemically activated, and/or heated. Externally added non-chemically reactive gas, e.g. C02, N2, etc., allows for direct injection rather than relying on the chemical reaction to take place to more specifically manipulate the product at will by releasing real-time adjusted defined amounts of the non-chemically reactive gas to adjust product expansion, depending on targeted finished product texture. Thus, the addition of the non-chemically reactive gas enriches the process by helping control textural properties in a highly flexible manner, with minimal effect on pH.

The various created textures are aligned with the various end use and customer profiles. Various applications can require various textures of the crisp. Some of the applications include: cereals, salad croutons, yogurt toppings, stand-alone snacks, sweet-snacks (candy or chocolate coated), and bars.

In some applications, the texture is needed to be quite soft, and in others it is needed more firm. High alkali addition, high moisture, and high temperature conditions (e.g., external heat applied), favor crisps with firm texture. Intermediate alkali addition, low to intermediate moisture levels, and process-driven heating conditions (e.g., cooling applied, but not enough power to overcome frictional dissipation), favor soft to carbohydrate-like textures. Low alkali addition, low to intermediate moisture levels, and process-driven heating conditions, favor expanded crisps with larger air cells and glassy texture.

The texture is further modified by the introduction of non-chemically reactive gas. As more non-chemically reactive gas becomes entrapped within the melted MPI, crisps coming from the extruder decrease in density and the texture after drying becomes softer, that is, requires less force to bite through with one’s molars. Such a change in density is considered “lightened” texture as opposed to“heavier” texture in which the piece requires more force to bite through, and without proper expansion might not be crispy at all.

The relation between the non-chemically reactive gas quantity and the final product texture depends on extrusion and feed variables, including but not limited to the following parameters:

• Feed: pH, pH modifiers type and concentration, non-chemically reactive gas and concentration

• Extrusion variables: Feed rates, screw configuration, screw speed, barrel temperatures, die geometry

• Process response variables: specific mechanical energy, pressure at the die These variables and others affect the incorporation of dissolved gas, including not limitative to native steam and carbon dioxide as well as non-chemically reactive gasses injected, in the melted MPI and the ability of the MPI to retain a porous structure upon exiting the die. The effect is that low levels of gas incorporation will help nucleate air cells in the crisp. This will increase the number of pores and will normalize size distribution. As the level of gas dissolved in the melted MPI increases, MPI air cell size will increase, the pore size distribution will widen, and cellular walls will become thinner. When gas incorporated into the melted MPI becomes too high or melt viscosity at the die is too low, the MPI cell walls will stretch to their breaking point, and the newly generated air cell will collapse onto itself. Structures between cells will appear thicker due to multiple walls stacking upon each other. The effects of non-chemically reactive gas on crisps can be qualified through several different measurement techniques focusing on density, porosity, and pore size distribution: • Expansion Ratio: Diameter of the extrudate divided by the diameter of the die. Alternatively, cross-sectional area of the extrudate to open area of a single die opening may be used.

• Bulk Density (p_buik): Crisp mass divided by the total volume of the same mass bulk density from 40 to 350 g/L

• True Bulk Density (p-n-ue): Extrudate mass divided by only the volume occupied by that mass. True volume of the extrudate can be determined from geometric calculation, volumetric displacement, or pycnometry, provided the MPI cell walls do not allow for measuring fluid permeation.

• Piece Density (p_PieCe): Mass of an individual crisp divided by the volume occupied by that mass. Such measurements become impractical as piece size becomes less than 10 mm in diameter.

• Porosity (0): Porosity is the measure of the volumetric fraction of air entrapped within crisps. Unity minus the ratio of true bulk density to solids density equals porosity. Solids density can be measured by pycnometry after milling crisps to dust to break walls of all air cells, or by mathematics using the known solids densities of the macronutrients in MPI and their concentrations. Piece porosity can be calculated by substituting true bulk density with piece density. Such substitutions become impractical when size becomes less than 10 mm.

• Pore Size and Distribution: Microscopic images of crisp interiors can be taken and electronically processed to acquire pore diameters from which pore size distributions can be generated. Based on average pore size diameter and, assuming spherically shaped pores, the number of cells per volume can be mathematically calculated.

The reactions taking place inside the extruder are complicated and need to be managed to control texture. The external usage/addition of a non-chemically reactive gas to supplement the alkalis can be beneficial towards achieving the desired texture of the crisp, but the adding process requires a lot of care.

Various alkalis, including and not limited to, calcium hydroxide, magnesium hydroxide, sodium hydroxide, and sodium bicarbonate, and alkali substances, can be added to the extruder. It is possible to mix the alkalis with the proteins and to add them together prior to extrusion process. It is also possible to add the alkalis separately to the front end of the extruder into its open feeding barrels/screws during the extrusion process.

In order to analyze the relationship between the product properties and the added alkali quantities, a series of experiments are done under different production conditions. Different percentages by weight of calcium hydroxide (Ca(OH)2) and sodium bicarbonate (NaHC03) are mixed together to form the alkali blend, which is added into the proteins such as MPI. It is discovered that for similar levels of added alkali, the radial expansion index (REI) was typically higher and bulk density lower with increasing percentage of NaHC03.

The increase of alkali addition level corresponds to the increase of pH value. Inside the product, the air cell size and air cell wall thickness decrease as the alkali addition level increases, which increases also the pH value. For the calcium hydroxide (Ca(OH)2) dominant alkali blends, in which the percentage of Ca(OH)2 is more than 50%, the air cell wall thickness decreases until its breaking point, which leads to the structural collapse. Reducing the calcium hydroxide (Ca(OH)2) percentage leads to smaller, almost unidentifiable air cells to the naked eyes.

In order to qualify the texture of the product, the hardness and the glassiness are analysed. Hardness is determined as the force required to bite completely through one crisp with one’s molars. Crisps with low levels of added alkali and low pH values are crisps with large air cells and rather non-uniform air cell size distribution, which are softer than crisps with smaller air cells. The glassiness refers to the level or intensity of pointy particles remaining on one’s palate after three to five chews. In general, the alkali blends with lower concentrations of calcium hydroxide (Ca(OH)2) have lower glassiness ranking. However, too much sodium bicarbonate may impart a pasty mouth feel and a high level of tooth packing. Thus, the preferred range to achieve non-extreme hardness and glassiness results, of percentage by weight of Ca(OH)2 / NaHC03 in the alkali blend, is from 60% / 40% to 75% / 25% with an alkali addition level corresponding to the pH value from 5.8 - 6.5. Photos of the protein product produced under the above-mentioned conditions are illustrated in the figure 2. The bulk density is between 80-100 g/L, and the radial expansion index is between 3.0-3.1.

Ca(OH)2 dissolution produces heat, which increases melted protein viscosity and increases extruder motor intensity. Consequently added water increases to both cool the melt and to decrease its viscosity. Since the melt is too hot and fluid upon leaving the die it is more difficult to produce crisps with softer, more airy texture as the structure collapses back on itself. Texturally hard crisps lacked radial expansion. The non-chemically reactive gas (e.g., dry ice) can be added in solid phase, which undergoes phase change to the gaseous state within the extruder. This phase change absorbs heat and can give a cooling effect. Additionally, the C02 evaporates after the phase change and avoids the problem introduced by adding water. It is possible to introduce the solid-state non-chemically reactive gas by the same feeder into the extruder with the alkalis and/or proteins, or via a separate feeder. The addition rates are controlled by loss in weight gravimetric feeders or volumetric feeders previously calibrated for the targeted addition rates.

When the non-chemically reactive gas is added in gas state into the extruder, it can be added in multiple ports of the extruder to ensure that the gas gets integrated into the melted MPI prior to exiting the extruder to produce expansion as it exits. Particularly, the addition of these alkalis and non-chemically reactive gases must be conducted in a safe manner using properly measured pressures. When injecting gas into the extruder barrel, backpressure of the gas must be greater than pressure within the extruder to ensure that gas flows into barrel and to prevent melted MPI from flowing into the gas line. Thus, it is necessary to introduce the non-chemically reactive gas at a lower pressure port of entrance of the extruder. Low pressure within the extruder can be generated by carefully designing the screw profile.

No matter how the non-chemically reactive gas is added, the gas addition rate can be controlled and monitored by an electronic controller.

For the experience with CO2, MPI was extruded with alkali. The alkali blend was prepared at approximately 75% / 25% Ca(OH)2 / NaHCOs and rate set at 1.9%. The C02 is added by dry ice in 3 mm pellets. The adding sequence is illustrated in the figure 3, where MPI, alkali and dry ice percentage are calculated with respect to each other, and water percentage is calculated with respect to all others. Dry ice addition rate is increased throughout the trial. Crisps at different dry ice levels (treatments 2-5) are collected at approximately 1.5%, 2.3%, 3.1 % and 5.3% added dry ice while keeping all other inputs fixed. Treatment 6 is no alkali and 5.3% dry ice. The results of treatments 1-6 are listed in the table below.

Alkali Dry-Ice Bulk

Treatment Moisture REI

Rate Rate pH Density

# (%)

(%) (%) (g/L) (-)

1 2.0 0.00 2.5 ± 0.0 6.5 ± 0.0 90 ± 2 3.0 ± 0.03

2 1.9 1.5 2.6 ± 0.1 6.4 ± 0.0 79 ± 1 3.1 ± 0.04

3 1.9 2.3 2.6 ± 0.0 6.4 ± 0.0 77 ± 1 3.1 ± 0.00

4 1.9 3.1 2.8 ± 0.1 6.5 ± 0.1 77 ± 2 3.1 ± 0.00

5 1.9 5.3 2.9 ± 0.1 6.4 ± 0.0 75 ± 1 3.2 ± 0.04

6 0.0 5.3 3.0 ± 0.0 5.1 ± 0.1 67 ± 0 3.5 ± 0.07

From the above table, it is seen clearly that the moisture content is always less than 5%. The pH value for crisps produced at near-constant alkali addition is around 6.4-6.5. There is no impact of dry ice on the pH value. Thus, it is considered that the changes in crisp properties are due to the dry ice addition. When alkali addition stopped, crisp pH decreases to 5.1.

REI increases when dry ice feeds starts. Without dry ice, the REI is around 3.0, while with dry ice, the radial expansion index increases to about 3.1. Expansion difference between 1.5% and 3.1 % added dry ice is not noticeable. Increasing dry ice addition to 5.3%, while keeping the protein to alkali ratio fixed in treatment 5, increases REI to around 3.2. Stopping alkali addition and relying on dry ice as the only nucleating agent increases crisp length and diameter such that REI is about 3.5.

Finished crisp bulk density is a function of dry ice addition. The bulk density is around 90g/L at 0% dry ice addition (treatment 1 ). The bulk density stays constantly around 75g/L at dry ice addition rates varying from 1.5% - 5.3% (treatment 2-5). A noticeable decrease in bulk density is realized when alkali addition is shutoff and dry ice is the only nucleating agent. Bulk density of treatment 6 at 0% alkali and 5.3% dry ice is about 67g/L, which is notably lower than the bulk density of 120g/L at 0% alkali and 0% dry ice crisps. Thus, it is considered that adding dry ice lowers crisp bulk density with and without added alkali.

Adding dry ice decreases crisp hardness and glassiness, the difference of which is quite evident between the treatment 1 (0% dry ice) and 2 (1.5% dry ice). Differences are difficult to ascertain between 1.5% and 3.1 % added dry ice. After all, bulk density differences in that range were not pronounced. Crisps from treatment 5 (5.3% dry ice) were slightly softer than those crisps produced with lower levels of dry ice addition. Treatment 6 crisps were the softest. These crisps were less glassy than the control and had tender, flaky structure. Off- flavour was apparent in treatment 6 since at pH 5.1.

Another advantage of this method is to allow adding heat-sensitive flavors and nutritional components to the mixture efficiently and cost-effectively since lower processing temperatures are expected with non-chemically reactive gas injection.

The approach of modifying texture through alkali and non-chemically reactive gas usage assists in protecting volatile components such as flavors and heat-liable components such as vitamins. Most standard flavors and vitamins (e.g., Vitamin C) cannot tolerate the heat and pressure associated with extrusion, since traditionally, the expansion relies on the generation of steam from heat. The alkali/ non-chemically reactive gas combination allows to lower the processing temperatures due to the fact that the expansion comes from the injected non- chemically reactive gas rather than the generated steam alone. In addition, the pressure of the injected non-chemically reactive gas is adjusted in a controllable manner.

This method also allows adding even more components directly to the mixture, hence addressing lower protein products as well. This extra texturization also allows other components to be added to develop and produce lower protein crisps successfully in such a system. This may include components, which otherwise may be a scorching candidate or may not easily be expanded/texturized, but can be protected in this arrangement.

Claims

Revendications

1. A method for modifying a texture of a protein product, said method comprising the steps of:

a. Creating in an extruder a mixture including protein materials, alkalis, non- chemically reactive gas and water,

b. introducing said mixture through a die engaged with said extruder,

c. forcing the mixture though the opening of the die under pressure,

d. allowing expansion of the mixture under atmospheric pressure;

e. removing moisture from the expanded mixture to form the protein product.

2. The method according to claim 1 wherein the non-chemically reactive gas is introduced into the extruder through a gas injection system, which contains a compressed gas bottle and a series of valves.

3. The method according to claim 2 wherein within the injection system, the gas pressure upstream of the injection system is greater than the gas pressure at the injection point to the extruder.

4. The method according to claim 2 wherein within the extruder, the gas pressure profile depends on the geometrical configuration of the extruder and of the die.

5. The method according to claim 1 wherein the non-chemically reactive gas is introduced in its solid phase into the extruder via a feeder.

6. The method according to claim 1 wherein the non-chemically reactive gas is introduced by effervescent compounds in solid phase into the extruder via a feeder, wherein effervescent compounds release gas upon contacting water.

7. The method according to claim 1 wherein alkalis, non-chemically reactive gas and the protein materials are added together.

8. The method according to claim 1 wherein alkalis and/or non-chemically reactive gas are/is added separately from the protein materials (this claim includes several possibilities: alkalis + non-chemically reactive gas, alkalis alone, non-chemically reactive gas alone is added separately)

9. The method according to any precedent claim, wherein the non-chemically reactive gas is carbon dioxide, nitrogen, or any other compressed gas sources.

10. The method according to claim 1 wherein a high protein product contains at least 70% crude protein on dry-basis.

1 1. The method according to claim 1 wherein a lower protein product contains less than

70% crude protein on dry-basis.

12. The method according to claim 1 wherein the temperature at the extruder is between 4°C and 121 °C degrees.

13. The method according to claim 1 wherein the injection pressures inside the compressed gas bottle range from 15 pound-force per square inch (psig) to the critical pressure of the non-chemically reactive gas at ambient temperatures.

14. The method according to claim 1 wherein the protein product has a bulk density from 40 to 350 g/L.