Methods for processing animal protein

Abstract

The presently disclosed subject matter provides methods for treating animal protein and pet food products containing same, the methods comprising treating the animal protein with one or more basic compounds to increase its pH and provide improved shelf life and reduced spoilage of the animal protein.

Description

Technical Field

[0001] The subject matter of the present disclosure relates to animal proteins and methods of processing them. Specifically, the animal proteins of the present disclosure can be treated with one or more base components to advantageously enhance the preservation of the animal proteins and reduce degradation. The animal proteins processed in accordance with the present disclosure can be used in combination with other components to form, for example, pet food products.

Background Art

[0002] Pet food products provide a wide range of means for feeding pets. With respect to manufactured pet food products, there is an increasing demand for incorporating natural ingredients that enhance freshness and quality while also providing the convenience of a longer shelf life. The freshness of raw materials such as meat and viscera, and the reduction of their fermentation, have been achieved in various ways, such as by lowering the temperature of the ingredients for freezing or cooling. Other known methods include acidifying the raw materials or reducing the pH of the raw materials. For example, commercially available products that lower the pH to reduce or prevent the growth of bacteria and preserve the raw materials are readily available. Improving both the quality and freshness of the dry and wet animal proteins used in such pet food products improves the product performance of pets due to improved palatability.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Therefore, there is an increasing consumer demand for the production of pet food containing raw materials with high levels of freshness and quality, and for the manufacturing methods thereof. Components that can maintain the integrity during processing and enhance the palatability of pet food products are continuously needed. The subject matter of the present disclosure addresses these and other needs.

Means for Solving the Problems

[0004] The subject matter of this disclosure provides a process for processing animal proteins. Such processed proteins can be used in combination with other ingredients to form pet food products. Surprisingly, it has been advantageously found that raising the pH of animal proteins using basic components reduces fermentation and leads to improved freshness and quality of such raw materials. By raising the pH of raw materials according to this disclosure, spoilage and fermentation of raw materials can be advantageously reduced or prevented. Furthermore, the quality of pet food can be improved by obtaining fresher raw materials due to such processed animal proteins, for example, as indicated by the level of biogenic amines. This improvement in quality can affect palatability and can also advantageously affect side effects caused by biogenic amines.

[0005] This disclosure provides a method for processing one or more protein sources, which may include adding one or more base components to one or more protein sources. The processed protein sources may have a histamine level of less than about 300 ppm. In certain non-limiting embodiments, the processed protein sources may have a histamine level of about 10 ppm to about 200 ppm. According to one aspect thereof, the present invention relates to a method for processing one or more protein sources, which includes adding one or more base components to the protein sources, wherein the processed protein sources have a histamine level of less than about 300 ppm.

[0006] In certain non-limiting embodiments, the base component may include sodium hydroxide (NaOH). In certain non-limiting embodiments, the base component is sodium hydroxide (NaOH) alone. In certain non-limiting embodiments, sodium hydroxide may be present in an amount of about 0.25% to about 0.5% by mass.

[0007] In certain non-limiting embodiments, a basic component is added without the addition of an acidic component.

[0008] In certain non-limiting embodiments, one or more protein sources may include animal proteins, proteins derived from animals, or a combination thereof. In certain non-limiting embodiments, one or more protein sources may include organs.

[0009] In certain non-limiting embodiments, the treated animal protein may have a pH of about 5 to about 8. In certain non-limiting embodiments, the treated animal protein may have a pH of about 6 to about 7.

[0010] The above is a broad overview of the features and technical advantages of this application, in order to better understand the detailed description below. Additional features and advantages of this application that form the subject matter of the claims of this application are described below. Those skilled in the art should recognize that the disclosed concepts and particular embodiments can be readily used as a basis for modifying or designing other structures to carry out the same objectives of this application. Those skilled in the art should also recognize that such equivalent structures do not deviate from the spirit and scope of this application as set out in the appended claims. Novel features considered to be characteristic of this application, along with further objectives and advantages, with respect to both their configuration and method of operation, will be better understood from the following description. [Brief explanation of the drawing]

[0011] [Figure 1A] A graph showing the results of preservation tests performed by treating unground internal organs with potassium hydroxide (KOH) as a basic component at various final concentrations, according to Example 1 and certain non-limiting embodiments. Horizontal axis: KOH level expressed in mass %. Vertical axis: amount of histamine expressed in ppm. The amount of histamine (in ppm) is represented by a curve with a diamond shape. The pH value is represented by a curve with a square shape. [Figure 1B]Graph showing the results of preservation tests performed by treating pulverized internal organs with potassium hydroxide (KOH) as a base component at various final concentrations, according to Example 1 and certain specific non-limiting embodiments. Horizontal axis: KOH level expressed in mass %. Vertical axis: amount of histamine expressed in ppm. The amount of histamine (in ppm) is represented by a curve with a diamond shape. The pH value is represented by a curve with a square shape. [Figure 2A] A graph showing the results of preservation tests performed by treating unground internal organs with sodium hydroxide (NaOH) as a basic component at various final concentrations, according to Example 1 and certain non-limiting embodiments. Horizontal axis: NaOH level expressed in mass %. Vertical axis: amount of histamine expressed in ppm. The amount of histamine (in ppm) is represented by a curve with a diamond shape. The pH value is represented by a curve with a square shape. [Figure 2B] A graph showing the results of preservation tests performed by treating pulverized internal organs with sodium hydroxide (NaOH) as a basic component at various final concentrations, according to Example 1 and certain specific non-limiting embodiments. Horizontal axis: NaOH level expressed in mass %. Vertical axis: amount of histamine expressed in ppm. The amount of histamine (in ppm) is represented by a curve with a diamond shape. The pH value is represented by a curve with a square shape. [Figure 3] A graph showing the results of preservation tests conducted by treating poultry feed containing organs with sodium hydroxide (NaOH) as a basic component at various final concentrations and for various durations, according to Example 2 and certain non-limiting embodiments. Each bar on the horizontal axis of the graph represents the amount of histamine (in mg / kg) for each of the above conditions. Vertical axis: amount of histamine in mg / kg. [Figure 4] A graph showing the results of preservation tests conducted by treating poultry feed containing organs with sodium hydroxide (NaOH) as a basic component at various final concentrations and for various durations, according to Example 2 and certain non-limiting embodiments. Each bar on the horizontal axis of the graph represents the amount of cadaverine (in mg / kg) for each of the above conditions. The vertical axis represents the amount of cadaverine expressed in mg / kg. [Modes for carrying out the invention]

[0012] The subject matter of this disclosure relates to animal proteins and methods for processing them. Specifically, the animal proteins of this disclosure may be processed with one or more base components. Surprisingly, it has been advantageously found that increasing the pH of the animal proteins reduces or prevents material degradation. The animal proteins processed according to this disclosure can be used in combination with other components to form, for example, pet food products. These and other aspects of the disclosed subject matter are discussed in further detail below.

[0013] For the sake of clarity, and not to limit, this detailed explanation can be divided into the following sub-sections: 1. Definition; 2. Sources of animal protein; 3. Pet food composition; 4. Method for producing pet food compositions; and 5.Uses.

[0014] 1.Definition The terms used herein generally have the common meaning in the art within the context of this subject matter and in the specific context in which each term is used. Certain terms are defined below to provide additional guidance in describing the composition and methods of the disclosed subject matter, as well as the methods of manufacturing and using them.

[0015] As used herein and in the appended claims, the singular forms "a," "an," and "the" refer to multiple subjects unless the context specifically indicates otherwise. Thus, for example, a reference to "one (a) compound" includes a mixture of compounds.

[0016] The terms "about" or "approximately" mean within an acceptable error range of a particular value determined by a person skilled in the art, which in part depends on the method of measuring or determining the value, i.e., the limitations of the measurement system. For example, "about" can mean within 3 standard deviations or more than 3, in accordance with the practice in the relevant technical field. Alternatively, "about" can mean within a range of up to 20%, preferably up to 10%, more preferably up to 5%, and even more preferably up to 1% of a given value. Also, particularly with respect to a system or process, this term can mean within one digit, preferably within 5 times, and more preferably within 2 times of a value.

[0017] As used herein, the terms "animal" or "pet" refer to animals, including but not limited to dogs, cats, etc. Pet dogs and pet cats are specific non-limiting examples of animals or pets.

[0018] As used herein, the term "animal protein" refers to a protein source based on animals. Such animal proteins include, for example, but are not limited to, meat (e.g., pork, beef, or veal), poultry (e.g., chicken), fish, organs (e.g., liver, spleen, or heart), viscera (e.g., chicken or pork viscera), and combinations thereof.

[0019] As used herein, the terms "comprising", "including", or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0020] As used herein, the term "nutritionally complete" refers to a pet food product that contains all known nutrients required by the intended beneficiary of the pet food product, in all appropriate amounts and proportions, based on the recommendations of a recognized jurisdiction in the field of animal nutrition, for example. Thus, such a food can serve as a dietary source for maintaining life without the addition of supplementary nutritional sources. As used herein, the term "nutritionally balanced" refers to a pet food product that may be nutritionally complete. Alternatively, "nutritionally balanced" as used herein can also refer to a pet food product that is not nutritionally complete.

[0021] As used herein, the term "palatability" or "palatable" refers to being desirable to taste or preference. Further, the term "palatability" or "palatable" as used herein refers to the degree to which a pet food product appeals to the taste or preference of an animal. This is suitable for measurement in feeding tests, such as discrimination tests or ranking tests. In certain embodiments, "palatability" can mean that one food is relatively preferred over another food. For example, if an animal prefers one of two or more foods, the preferred food is more "palatable" and has "enhanced palatability" or "improved palatability". In certain embodiments, the relative palatability of one food compared to one or more other foods can be determined, for example, by the relative consumption of the foods, or by other appropriate preference scales indicating palatability, such as in a comparison of concurrent free choices.

[0022] As used interchangeably herein, the term "pet food" or "pet food composition" refers to a composition intended for ingestion by an animal or pet. Pet food can include, but is not limited to, daily feed and nutritionally balanced compositions suitable as snacks that can be nutritionally balanced.

[0023] As used herein, the term "protein source" refers to a source of animal protein, a source of animal-derived protein, or a combination thereof.

[0024] As used herein, the term “internal organs” refers to the intestinal portion of the body. Internal organs may further include other internal organs of the body, such as the heart, stomach, or lungs, in natural proportions.

[0025] As used herein, the term “weight percentage” means, for example, the amount by weight of a component or ingredient in a pet food composition as a percentage of the total weight of the pet food composition. The term “weight percentage” can also mean, for example, the amount by weight of a component or ingredient in a hydrolyzate composition as a percentage of the total weight of the hydrolyzate composition. The terms “weight percentage,” “weight%,” “wt%,” and “mass%” are used interchangeably.

[0026] 2. Methods for processing animal protein In certain non-limiting embodiments, the animal proteins of this disclosure can be treated according to the processes disclosed herein. In certain embodiments, the pH of the animal proteins can be increased by one or more base components. Such treatment has surprisingly and advantageously resulted in reduced degradation and improved storage properties of the animal proteins.

[0027] Animal protein sources In certain non-limiting embodiments, one or more protein sources may include animal protein, animal-derived protein, or a combination thereof. One or more protein sources may include animal protein sources such as chicken or pork. One or more protein sources may include, for example, trachea, kidney, liver, or organs. As used herein, the term “protein” means one or more proteins appropriately provided by one or more ingredients. Protein may appropriately be animal protein, animal-derived protein, or any combination thereof. Animal protein includes animal-derived protein (including vertebrate and invertebrate proteins), for example, protein from mammals, poultry, fish, and insects. Suitable examples of animal protein include those derived from chicken, turkey, beef, lamb, pork, venison, buffalo, duck, kangaroo, shellfish, crustaceans, salmon, tuna, white fish, etc. They may appropriately be derived from muscle, organs, tendons, bones, etc. The protein may be in any suitable form, e.g., isolated or partially isolated; concentrated; ground, etc. For example, one or more protein sources may include, but are not limited to, one or more of the following: pig trachea, pig kidney, poultry parts, chicken liver, chicken viscera, chicken neck, organs, turkey carcass, or a combination thereof. In certain non-limiting embodiments, one or more protein sources may include, for example, chicken, turkey, pig, beef, lamb, or fish liver. Those skilled in the art will recognize that a wide variety of protein sources are suitable for use in this disclosure.

[0028] In certain non-limiting embodiments, one or more protein sources may include animal organs, such as poultry organs. Such raw materials may be susceptible to fermentation and degradation. Furthermore, the state of the material may affect the rate and occurrence of fermentation and degradation. For example, since enzymes in ground organs may be mixed with bacteria and substrates, ground organs may be more susceptible to fermentation and degradation than natural or unground organs.

[0029] In certain non-limiting embodiments, the initial pH of one or more protein sources may be about 5 to about 7, about 5 to about 6.5, or about 5 to 6. In certain non-limiting embodiments, the initial pH of one or more protein sources may be about 5, about 5.5, about 6, or about 6.5. Those skilled in the art will recognize that the initial pH of one or more protein sources may vary, for example, depending on the raw materials and their state (e.g., ground or unground).

[0030] In certain non-limiting embodiments, one or more protein sources may be cooled or refrigerated before processing. In certain non-limiting embodiments, water may be at least partially removed from one or more protein sources. In certain non-limiting embodiments, one or more animal proteins may be mixed together.

[0031] Basic components In certain non-limiting embodiments, one or more protein sources can be treated with one or more base components. The pH of one or more protein sources can be increased using one or more base components. The one or more base components may include any suitable base compounds. Those skilled in the art will recognize that a wide variety of base components are suitable for use in this disclosure. In certain embodiments, the one or more base components may include sodium hydroxide (NaOH) or potassium hydroxide (KOH). In certain embodiments, the base components include only sodium hydroxide (NaOH).

[0032] In certain non-limiting embodiments, one or more base components can be added to one or more protein sources at final concentrations of about 0.1% to about 5% by mass, about 0.1% to about 4% by mass; about 0.1% to about 3% by mass; about 0.1% to about 2% by mass; about 0.1% to about 2% by mass; about 0.1% to about 1.5% by mass; about 0.1% to about 1.0% by mass; or about 0.1% to about 0.5% by mass. In further non-limiting embodiments, one or more base components can be added to one or more protein sources at final concentrations of about 0.25% to about 5% by mass, about 0.25% to about 4% by mass; about 0.25% to about 3% by mass; about 0.25% to about 2% by mass; about 0.25% to about 2% by mass; about 0.25% to about 1.5% by mass; about 0.25% to about 1.0% by mass; or about 0.25% to about 0.5% by mass. In further non-limiting embodiments, one or more base components can be added to one or more protein sources at final concentrations of about 0.5% to about 5% by mass, about 0.5% to about 4% by mass; about 0.5% to about 3% by mass; about 0.5% to about 2% by mass; about 0.5% to about 2% by mass; about 0.5% to about 1.5% by mass; or about 0.5% to about 1.0% by mass. In certain non-limiting embodiments, one or more base components can be added to one or more protein sources at final concentrations of about 0.1% by mass, about 0.25% by mass, about 0.5% by mass, about 0.75% by mass, about 1% by mass, about 1.2% by mass, about 1.4% by mass, about 1.5% by mass, or about 2% by mass.

[0033] In certain non-limiting embodiments, one or more base components comprise about 0.25% to about 0.5% by mass of sodium hydroxide (NaOH). In certain embodiments, one or more base components comprise only about 0.25% to about 0.5% by mass of sodium hydroxide (NaOH).

[0034] In certain non-limiting embodiments, the pH of one or more protein sources after treatment may be in the range of about 5.1 to about 8, about 6 to about 7.8, about 6.5 to about 7.5, or about 6 to about 7. In certain non-limiting embodiments, the pH of one or more protein sources after treatment may be about 6, about 6.5, about 7, about 7.2, about 7.5, or about 7.8.

[0035] One or more base components can be uniformly applied to one or more protein sources. For example, in certain non-limiting embodiments, one or more base components can be sprayed onto one or more protein sources.

[0036] Characteristics of processed protein sources Protein sources processed according to this disclosure surprisingly benefit from reduced or prevented material degradation. By increasing the pH of raw materials according to this disclosure, spoilage and fermentation of raw materials can be advantageously reduced or prevented. Furthermore, the quality of pet food can be improved by obtaining fresher raw materials by increasing the pH according to the method of this disclosure. Such quality can affect palatability and, furthermore, can advantageously affect side effects caused by biogenic amines.

[0037] In certain non-limiting embodiments, the treated protein source may have histamine levels ranging from about 0 ppm to about 500 ppm, about 10 ppm to about 300 ppm, about 100 ppm to about 200 ppm, from about 10 ppm to about 200 ppm, or about 10 ppm to about 150 ppm. In certain non-limiting embodiments, the treated animal protein may have histamine levels ranging from about 0 ppm, about 10 ppm, about 15 ppm, about 50 ppm, about 100 ppm, about 125 ppm, about 150 ppm, about 200 ppm, about 250 ppm, about 275 ppm, about 300 ppm, or about 500 ppm. In certain non-limiting embodiments, the treated animal protein may have histamine levels of less than approximately 500 ppm, less than approximately 300 ppm, less than approximately 250 ppm, less than approximately 200 ppm, less than approximately 100 ppm, less than approximately 50 ppm, or less than approximately 25 ppm.

[0038] In certain non-limiting embodiments, the treated protein source may have histamine levels of approximately 0 mg / kg to approximately 200 mg / kg, approximately 10 mg / kg to approximately 150 mg / kg, approximately 100 mg / kg to approximately 150 mg / kg, approximately 10 mg / kg to approximately 90 mg / kg, or approximately 10 mg / kg to approximately 50 mg / kg. In certain non-limiting embodiments, the treated animal protein may have histamine levels of approximately 0 mg / kg, approximately 1 mg / kg, approximately 5 mg / kg, approximately 10 mg / kg, approximately 15 mg / kg, approximately 25 mg / kg, approximately 50 mg / kg, approximately 100 mg / kg, approximately 125 mg / kg, approximately 150 mg / kg, or approximately 200 mg / kg. In certain non-limiting embodiments, the treated animal protein may have histamine levels of less than approximately 200 mg / kg, less than approximately 150 mg / kg, less than approximately 100 mg / kg, less than approximately 90 mg / kg, less than approximately 50 mg / kg, less than approximately 25 mg / kg, less than approximately 15 mg / kg, less than approximately 10 mg / kg, less than approximately 5 mg / kg, less than approximately 2 mg / kg, or less than approximately 1 mg / kg.

[0039] Methods for measuring the amounts of histamine, other biogenic amines such as putrescine, cadaverine, spermine, spermidine, thiamine, tryptamine, 2-phenylethylamine, serotonin, or agmatine, and hexanal are well known to those skilled in the art. Examples of methods for measuring these amounts are also disclosed in the experimental section of this specification.

[0040] 3. Pet food composition In certain non-limiting embodiments, a pet food composition is provided. The pet food composition may comprise one or more processed animal proteins as described herein, and optionally one or more additional components, such as dry components, liquid components, or a combination thereof. Those skilled in the art will recognize that a wide variety of pet food compositions are suitable for use in this disclosure.

[0041] 4. Method for producing pet food composition In certain non-limiting embodiments, a method for producing a pet food composition is provided. In certain non-limiting embodiments, one or more dry components can be mixed with one or more wet components to form an emulsion or dough. The emulsion or dough can be heated to a predetermined temperature under pressure and gradually cooled. Alternatively, an emulsion can be formed, crushed, heated to a predetermined temperature, and then introduced into a processing zone. In the processing zone, the emulsion can be subjected to a predetermined pressure and discharged. Alternatively, to produce a lump product, a slurry can be introduced into a scraping heat exchanger at a predetermined pressure and heated to produce a heat-treated product having a certain temperature. In certain non-limiting embodiments, one or more dry components can be mixed with one or more wet components, such as water, to form a dough. The dough can be cooked during extrusion under conditions of high temperature, high pressure, or a combination thereof. The extruder may be equipped with a die having a particular shape that can divide the extruded product into particles or fragments as the product is extruded.

[0042] Those skilled in the art will recognize that a wide variety of methods for producing pet food compositions are suitable for use in this disclosure.

[0043] 5.Applications The animal proteins processed in accordance with this disclosure can be used as raw materials together with other ingredients for forming pet food products. In certain non-limiting embodiments, the pet food composition may be used alone as a pet food product, or in combination with other ingredients to form a mixed pet food product. Any suitable pet food application can be used with the animal proteins of this disclosure. For example, but not limited to, the animal proteins processed in accordance with this disclosure may be suitable for use in dry, moist, for example, loaf or chunk form, of pet food products such as gravy, treats, bakery items, or pillows. [Examples]

[0044] The following embodiments are merely illustrative of the subject matter of this disclosure and should not be considered to limit the scope of the subject matter in any way.

[0045] In the following examples, the amounts of histamine, thiamine, putrescine, cadaverine, serotonin, phenylethylalamine, spermidine, spermine, tryptamine, and hexanal were measured as follows.

[0046] Analytical method for biological amine profiles: The principle involves acid extraction of biological amines and determination by high-performance liquid chromatography (HPLC-FLD) with fluorescence detection after o-phthalidine (OPA) column derivatization. This protocol is adopted from AOAC International (Association of Official Analytical Chemists - International) volume 78, n°4, 1995 and AOAC International volume 81, n°5, 1998. The extended [k=2] uncertainties for histamine, thiamine, putrescine, and cadaverine are as follows: - Value ≥ 10 mg / kg: 30% of the value - Value < 10 mg / kg: 40% of the value, the minimum value is 5 mg / kg (2 mg / kg for histamine).

[0047] The extended [k=2] uncertainty for serotonin is as follows: - 50% of the value.

[0048] The limit of quantification in the matrix is ​​2 mg / kg for histamine and 5 mg / kg for all other biogenic amines.

[0049] Analytical method for hexanal: The principle is to extract hexanal using static headspace extraction and analyze it using gas chromatography with a flame ionization detector (GC-FID) using internal quantification.

[0050] The extended uncertainty for hexanal [k=2] is 40%.

[0051] Example 1: Potassium hydroxide (KOH) and sodium hydroxide (NaOH) pretreatment test of internal organs (various final concentrations) Two basic compounds, potassium hydroxide (KOH) and sodium hydroxide (NaOH), were tested at different final concentrations during the pretreatment of animal organs. Animal organs were tested in both pulverized and unpulverized states. For potassium hydroxide (KOH) pretreatment, unpulverized animal organs were tested at final concentrations of 0%, 0.5%, 1%, 1.2%, 1.4%, and 1.5% by mass, while pulverized animal organs were tested at final concentrations of 0%, 0.75%, 1%, 1.2%, 1.4%, and 1.5% by mass. For sodium hydroxide (NaOH) pretreatment, unpulverized animal organs were tested at final concentrations of 0%, 0.25%, 0.5%, and 1% by mass, while pulverized animal organs were tested at final concentrations of 0.25%, 0.5%, 1%, and 1.5% by mass. Histamine levels (ppm) and pH were measured for all samples. Histamine is a byproduct of amino acid fermentation (histidine) and can be used as a tracer for biogenic amines. Low histamine levels may indicate that the raw materials are fresh.

[0052] The results of pretreatment of animal entrails with potassium hydroxide (KOH) are shown in Table 1A (unground) and Table 1B (ground), respectively, corresponding to Figure 1A (unground) and Figure 1B (ground). The results of pretreatment of animal entrails with sodium hydroxide (NaOH) are shown in Table 2A (unground) and Table 2B (ground), respectively, corresponding to Figure 2A (unground) and Figure 2B (ground).

[0053] [Table 1A]

[0054] [Table 1B]

[0055] [Table 2A]

[0056] [Table 2B]

[0057] As shown in Tables 1A-1B and 2A-2B, and Figures 1A-1B and 2A-2B, pretreatment of animal entrails (ground or unground) with sodium hydroxide (NaOH) was more efficient than pretreatment with potassium hydroxide (KOH). In both unground and ground animal entrails, pretreatment with sodium hydroxide (NaOH) increased the pH level and decreased the histamine level of the material.

[0058] Example 2: Pretreatment test of poultry feed containing internal organs with sodium hydroxide (NaOH) (0.25% by mass and 0.5% by mass of NaOH) Sodium hydroxide (NaOH) was tested over a period of time at final concentrations of 0%, 0.25%, and 0.5% by mass in the pretreatment of animal protein, i.e., poultry feed. Histamine levels (mg / kg) were measured at 1 hour, 5 hours, 12 hours, 20 hours, 24 hours, and 30 hours for each final concentration of sodium hydroxide (NaOH) pretreatment. Standard chicken entrails were removed from the slaughterhouse immediately after transport and screening. A homogeneous mixture of fresh entrails was divided immediately after slaughter into three containers of equal weight (i.e., "control," "NaOH added at 0.25% by mass," and "NaOH added at 0.5% by mass"). Approximately one hour after collection, 80% by mass carbonated water (soda) was added to each of the three containers. The three containers were then hand-blended for 30 seconds. The containers were kept in a controlled room maintained at 20°C throughout the test period. As shown in Table 3, samples were taken from each of the three containers at the same time point (T0-T5) and immediately stored in a freezer. A total of 16 samples were tested. The control was tested at T0, and all three containers (control, 0.25% by mass of NaOH, and 0.5% by mass of NaOH) were tested at T1-T5. Each container was stirred before each intermediate sampling step. After 30 hours of storage, all samples were dehydrated in an oven at 115°C for 24 hours, and then tested for hexanal (oxidized), biogenic amines, and sodium.

[0059] [Table 3]

[0060] The results of the hexanal, sodium, and biogenic amine tests are shown in Table 4. The histamine level (mg / kg) results are shown in Figure 3. The cadaverine level (mg / kg) results are shown in Figure 4.

[0061] [Table 4-1]

[0062] [Table 4-2]

[0063] As shown in Table 4 and Figure 3, which display the results for histamine levels (mg / kg), sodium hydroxide (NaOH) can be used to preserve animal proteins. A final concentration of 0.5% by mass of sodium hydroxide (NaOH) was more efficient in preserving animal proteins and had a greater effect on the pH of the animal proteins compared to a final concentration of 0.25% by mass of sodium hydroxide (NaOH). A higher final concentration of 0.5% by mass of sodium hydroxide (NaOH) raised the pH of the material to a more basic level compared to a final concentration of 0.25% by mass of sodium hydroxide (NaOH). As shown in Table 4 and Figure 3, the histamine levels of the material decreased in correlation with the increase in the final concentration of sodium hydroxide (NaOH), i.e., from 0%, 0.25%, to 0.5% by mass.

[0064] In addition to the various embodiments illustrated and claimed, the disclosed subject matter also covers other embodiments having other combinations of features disclosed and claimed herein. Thus, specific features presented herein can be combined with each other in other ways within the scope of the disclosed subject matter, such that the disclosed subject matter includes any suitable combination of the features disclosed herein. The foregoing descriptions of specific embodiments of the disclosed subject matter are presented for illustrative and explanatory purposes only. They are not intended to be exhaustive or to limit the disclosed subject matter to those disclosed embodiments.

[0065] It will be apparent to those skilled in the art that various modifications and variations can be made to the system and methods of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Accordingly, the disclosed subject matter is intended to include modifications and variations that fall within the scope of the appended claims and their equivalents.

Claims

1. A method for processing one or more protein sources, the method comprising the step of adding a basic component to the protein source, A method wherein the basic component is sodium hydroxide (NaOH) only, is added without the addition of an acidic component, and the sodium hydroxide (NaOH) is present at a concentration of about 0.25% by mass to about 0.5% by mass, and the treated protein source has a histamine level of less than about 300 ppm.

2. The method according to claim 1, wherein the one or more protein sources include animal protein.

3. The method according to claim 2, wherein one or more protein sources include internal organs.

4. The method according to claim 1, wherein the processed protein source has a histamine level of about 10 ppm to about 200 ppm.

5. The method according to claim 1, wherein the processed protein source has a pH of about 5 to about 8.

6. The method according to claim 5, wherein the treated protein source has a pH of about 6 to about 7.

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