Potato protein composition and feed composition for aquatic animals containing the same

Abstract

The present embodiment aims to provide a protein source having high palatability and digestibility and a feed composition for aquatic animals containing the same, and specifically, the present embodiment relates to a potato protein in which the content of potato glycoalkaloids is 300 ppm or less, and the content of free amino acids is 10,000 ppm or more and 75,000 ppm or less.

Description

Technical Field

[0001] This disclosure relates to potato protein compositions and aquatic animal feed compositions containing the potato protein compositions. Background Technology

[0002] In the past, fishmeal was often used as the main protein source for animal feeds such as aquatic animal feeds because of its high protein content, good amino acid balance, good feed intake / digestibility, and high contribution to animal weight gain.

[0003] However, due to factors such as climate change, overfishing of natural fish, and increased global fishmeal trade, fishmeal prices have soared, putting significant pressure on aquaculture farmers. Therefore, there is a growing demand for a protein source that is high in protein, has a well-balanced amino acid profile, is easily digestible and readily available, and can be supplied cheaply and stably. Japan's Ministry of Agriculture, Forestry and Fisheries' "Green Food System Strategy" requires that fishmeal substitution rates in freshwater fish feed reach over 80%, and in marine fish feed over 50%.

[0004] In this context, plant-based proteins with relatively stable yields and prices are anticipated as alternative protein sources to fishmeal. Among these, soybean meal, corn gluten meal, and potato protein have attracted attention due to their high protein content. However, soybean meal is low in methionine, an essential amino acid, and corn gluten meal is low in lysine, another essential amino acid, making them unsuitable as a substitute for fishmeal when used alone. On the other hand, potato protein contains a sufficient amount of all essential amino acids in its amino acid balance. However, like other plant-based proteins (including soybean meal and corn gluten meal), potato protein exhibits a higher molecular weight distribution compared to fishmeal, with lower levels of free amino acids. Therefore, compared to fishmeal, potato protein suffers from poor feed intake (daily feed intake rate) and digestibility (feed efficiency). Furthermore, it contains potato glycosides, which are anti-nutritional factors that inhibit feed intake (daily feed intake rate) in fish.

[0005] To date, the following method has been proposed as a way to improve the feedability (daily feed intake rate) / digestibility (feed efficiency) of potato protein: using potato protein with reduced potato glycoside alkaloid content and potato protein with physical properties controlled within a certain range as feed ingredients.

[0006] For example, Patent Document 1 discloses a potato protein with reduced potato glycoside alkaloid content. Additionally, Patent Document 2 discloses a potato protein that exhibits high feed efficiency by controlling the endothermic / exothermic temperature of a differential scanning calorimeter within a certain range.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2020-5606

[0010] Patent Document 2: WO2020 / 045295 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] While potato protein, as described in Patent Document 1 or 2, can replace approximately 30% of fishmeal, further increases in the fishmeal replacement rate lead to decreased feedability and digestibility. Therefore, there is a need for further development of alternative proteins that can replace fishmeal.

[0013] Therefore, the purpose of this disclosure is to provide a protein source that can maintain high feedability and digestibility even when it is used as a high-substitution of fishmeal, i.e., even when it is used as a high-substitution of fishmeal.

[0014] Problem Solving Methods

[0015] To solve the above problems, the inventors conducted repeated and dedicated research, and surprisingly discovered that even when using a potato protein composition with a high proportion of potato glycoside alkaloid content and free amino acid content within a given range to replace fishmeal, it still exhibited high feed intake (daily feed intake rate) and digestibility (feed efficiency), thus completing the present invention.

[0016] That is, the embodiments of the present invention include the following.

[0017] (1) A potato protein composition, wherein,

[0018] The content of potato glycoside alkaloids in the dried matter is below 300 ppm.

[0019] The content of free amino acids in the dried matter is above 10,000 ppm and below 75,000 ppm.

[0020] (2) The potato protein composition according to (1), wherein,

[0021] The crude protein content in the dried product is above 70% by weight.

[0022] (3) The potato protein composition according to (1) or (2), wherein,

[0023] The crude protein in the potato protein composition comprises more than 90% by weight crude protein from potatoes.

[0024] (4) The potato protein composition according to any one of (1) to (3) contains fermented potato protein.

[0025] (5) A feed composition for aquatic animals, comprising the potato protein composition described in any one of (1) to (4).

[0026] (6) A feed composition for aquatic animals, comprising potato protein, wherein,

[0027] The content of potato glycoside alkaloids in the dried product is less than 100 ppm.

[0028] The content of free amino acids in the dried product is above 4000 ppm and below 35000 ppm.

[0029] (7) The aquatic animal feed composition according to (6), wherein,

[0030] The crude protein content in the dried product is above 30% by weight.

[0031] (8) The aquatic animal feed composition according to any one of (6) or (7), wherein,

[0032] The crude protein in the feed composition for aquatic animals shall be more than 40% by weight of crude protein from potatoes.

[0033] (9) The aquatic animal feed composition according to any one of (6) to (8) further comprises fish meal, wherein the fish meal content is 50% by weight or less.

[0034] (10) The aquatic animal feed composition according to (9), wherein,

[0035] The fishmeal content is less than 30% by weight.

[0036] This specification contains the disclosure of Japanese Patent Application No. 2024-045234, which forms the basis of the priority claim of this application.

[0037] The effects of the invention

[0038] According to this disclosure, a protein source that can provide high feedability and digestibility can be provided even when used in a high proportion to replace fishmeal. Detailed Implementation

[0039] The embodiments of the present invention will now be described in detail.

[0040] <Potato Protein Composition>

[0041] This embodiment is a potato protein composition, wherein the content of potato glycoside alkaloids in the dried product is less than 300 ppm, and the content of free amino acids in the dried product is more than 10,000 ppm and less than 75,000 ppm.

[0042] In this specification, "potato protein" refers to protein derived from potatoes, specifically proteins extracted and isolated from potatoes. Potato proteins typically have a molecular weight of 1500 or higher, and are usually polypeptides with a molecular weight of 5000 or higher. Potato proteins can also be proteins that have undergone appropriate chemical modifications, such as sugar chain modifications. Furthermore, potato proteins are not limited to their natural state; they can also be denatured proteins. For example, potato protein can be extracted and separated from the juice obtained as a byproduct of potato starch production.

[0043] Potato protein composition refers to a composition containing potato protein extracted or isolated from potatoes, and may contain water, impurities, etc., depending on the circumstances. Substances other than protein components are typically substances with a molecular weight of 5000 or less, preferably substances with a molecular weight of 1500 or less. Furthermore, the potato protein composition may contain one or more types of potato protein. That is, the potato protein composition may also contain a mixture of two or more types of potato protein.

[0044] There are no particular limitations on the methods for extracting and separating potato protein from potatoes; for example, the following methods can be listed.

[0045] (1) Using potato juice, an aggregation process is performed to aggregate potato proteins through heating, salting out, etc. When aggregation is performed by heating, the heating temperature and heating time are not particularly limited; for example, a heating temperature of 90-120°C and a heating time of 1-60 minutes are examples. Heating can be performed using electricity or steam. When aggregation is performed by salting out, for example, lime solution can be added to the juice, and then the potato proteins are adsorbed onto calcium carbonate produced by bubbling in carbon dioxide.

[0046] (2) Use a dryer to dry the aggregated potato protein. There is no particular limit to the drying time, which can be adjusted appropriately to achieve the target moisture content. If necessary, the aggregated potato protein can be dehydrated using a dehydrator before drying.

[0047] (3) Further, the potato protein can be washed as needed. If washing is performed after the drying process in (2) above, the potato protein can be dried again using a dryer after washing. There is no particular limitation on the drying time, which can be adjusted appropriately to achieve the target moisture content.

[0048] The content of potato glycoside alkaloids in the potato protein composition of this embodiment is less than 300 ppm.

[0049] Potato glycoalkaloids are steroidal alkaloids that possess neurotoxic properties. Examples of glycoalkaloids found in potatoes include solanine and carvacrine.

[0050] The content of potato glycoside alkaloids in the potato protein composition of this embodiment is only required to be 300 ppm or less in dried matter, preferably 200 ppm or less, and more preferably 100 ppm or less. By setting the content of potato glycoside alkaloids within the above range, the feedability and digestibility of aquatic animals are improved when used as feed, which is therefore more preferable. The content of potato glycoside alkaloids can be determined by liquid chromatography-mass spectrometry (LC / MS). As a specific determination method, the following method can be used as an example. After micronizing the potato protein composition to be tested, it is sieved to obtain the undersize. 80% methanol solution is added to the obtained undersize and stirred, thereby extracting the potato glycoside alkaloids to the methanol side. The extracted liquid is recovered, and then solid-liquid separation is performed by centrifugation. After filtering out impurities, it is collected in a sample vial for HPLC as a sample. The obtained sample is subjected to HPLC-based analysis under the following conditions to determine the content of potato glycoside alkaloids.

[0051] Chromatographic column: Cosmosil 5C18 AR-II (4.6mm id × 250mm), manufactured by Nacalai Tesque Co., Ltd.

[0052] Mobile phase: 10 mM sodium phosphate aqueous solution containing 55% acetonitrile; 0.9 ml / min; Column temperature: 40℃

[0053] Detection wavelength: 202nm

[0054] Injection volume: 20μL

[0055] For example, when separating and extracting potatoes from potato protein, a washing process can reduce the content of potato glycoside alkaloids in the potato protein. Using potato protein with a reduced potato glycoside alkaloid content obtained through washing, a potato protein composition with a potato glycoside alkaloid content of 300 ppm or less can be prepared. Potato protein with a potato glycoside alkaloid content reduced to 300 ppm or less through washing can also be used directly as a potato protein composition. Alternatively, potato protein that has undergone a washing process and potato protein that has not undergone a washing process can be appropriately combined to prepare a potato protein composition with a potato glycoside alkaloid content of 300 ppm or less.

[0056] As a cleaning process, for example, a method can be described that includes the following steps: cleaning potato protein using one or more of an acidic aqueous solution and / or an alcohol.

[0057] First, the cleaning process using acidic aqueous solution will be explained.

[0058] Dried or undried potato protein is washed in a mixing tank with an acidic aqueous solution. From a cleaning point of view, the potato protein particles are preferably fine. Examples of acids used in the washing process include sulfuric acid, hydrochloric acid, or acetic acid. One acid may be used alone, or two or more may be used in combination.

[0059] The total amount of acid solution used in the washing process is not particularly limited, but relative to the weight of potato protein, it can be, for example, 10 times or more, preferably 20 times or more, more preferably 30 times or more, and more preferably 35 times or more. In the case of multiple washing operations, the amount of acid solution used in each washing operation relative to the weight of potato protein can be, for example, 5 times or more, preferably 8 times or more.

[0060] The pH of the acidic aqueous solution used in the cleaning is preferably 0.5 or higher and 4.0 or lower, more preferably 0.5 or higher and 3.5 or lower, and more preferably 0.5 or higher and 3.3 or lower. If the pH rises due to a reaction during stirring, an additional acidic aqueous solution may be added as appropriate.

[0061] The cleaning time using the acid solution is, for example, 2 to 12 hours. The cleaning temperature is, for example, 20 to 80°C.

[0062] After washing with an acidic aqueous solution and then dehydrating, wet protein is obtained.

[0063] To improve the cleaning efficiency, it is preferable to repeat the cleaning process using an acidic aqueous solution at least twice.

[0064] Preferably, after the washing process using an acidic aqueous solution, a pH adjustment process is performed to adjust the pH of the potato protein in the water. The pH of the potato protein in the water is preferably 4.0 or higher, preferably 5.0 or higher, preferably 6.0 or higher, preferably 6.5 or higher, and preferably 7.0 or higher. The pH of the potato protein in the water is not particularly limited, but for example, it is 10.0 or lower, preferably 9.0 or lower, and preferably 8.5 or lower. pH adjustment can be achieved by adding an appropriate amount of alkaline substances such as caustic soda to a dispersion formed by thoroughly dispersing the washed potato protein in an appropriate amount of water. If the pH changes during the pH adjustment process, an appropriate amount of alkaline substance should be supplied.

[0065] After the washing process, or after a pH adjustment process as needed, dehydration and / or drying can be performed. Drying can be carried out using a dryer. The drying temperature and time are not particularly limited and can be adjusted appropriately to achieve the target moisture content. After drying, pulverization can be performed as needed.

[0066] Next, the cleaning process using alcohol will be explained.

[0067] Dried or undried potato protein is washed with alcohol in a mixing tank. From a cleaning point of view, the potato protein particles are preferably fine. Examples of alcohols used for washing include methanol or ethanol. Alcohol can be used alone or in combination of two or more.

[0068] Cleaning using alcohol can be either alcohol-only or an aqueous alcohol solution (a mixture of alcohol and water). As an aqueous alcohol solution, it is preferable to mix it with water to achieve an alcohol concentration of 50% by weight or more.

[0069] The total amount of alcohol or aqueous alcohol solution used in the washing process is not particularly limited, but relative to the weight of potato protein, it can be, for example, 10 times or more, preferably 20 times or more, more preferably 30 times or more, and more preferably 50 times or more. When multiple washings are performed, the amount of alcohol or aqueous alcohol solution used in each washing cycle relative to the weight of potato protein can be, for example, 5 times or more, preferably 8 times or more.

[0070] The cleaning time using alcohol is, for example, 2 to 12 hours. The cleaning temperature is, for example, 20 to 50°C.

[0071] After washing with alcohol, the protein is dehydrated to obtain wet protein.

[0072] To improve the cleaning efficiency, it is preferable to repeat the cleaning process using alcohol more than twice.

[0073] After cleaning, it is preferable to wash with water to reduce the residual alcohol in the potato protein. Then, dehydration is preferred, achieved using a dryer. The drying temperature and time are not particularly limited and can be adjusted appropriately to achieve the target moisture content. After drying, pulverization can be carried out as needed.

[0074] The content of free amino acids in the potato protein composition of this embodiment is 10,000 ppm or more and 75,000 ppm or less in dried matter. Free amino acids refer to 20 free amino acids that exist in a free state, distinct from the amino acids constituting proteins. Specifically, they include alanine, asparagine, cysteine, glutamine, glycine, isoleucine, leucine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, aspartic acid, glutamic acid, arginine, histidine, and lysine. The content of free amino acids in the potato protein composition in dried matter is preferably 15,000 ppm or more, preferably 20,000 ppm or more, preferably 25,000 ppm or more, preferably 30,000 ppm or more, preferably 35,000 ppm or more, and preferably 40,000 ppm or more. The content of free amino acids in the potato protein composition in dried matter is preferably 70,000 ppm or less, preferably 65,000 ppm or less, and preferably 60,000 ppm or less. By setting the free amino acid content within the above range, the feed intake and digestibility of aquatic animals are improved when used as feed, making it more suitable.

[0075] The free amino acid content in a potato protein composition can be adjusted to a given range, for example, by adding free amino acids. Alternatively, it can be adjusted by fermenting potato protein to obtain fermented potato protein containing free amino acids. Furthermore, potato protein with increased free amino acid content through fermentation can be used directly as a potato protein composition. When using fermented potato protein, the free amino acid content can be appropriately adjusted according to the fermentation conditions. For example, the free amino acid content can be adjusted by the timing of fermentation cessation. That is, by stopping fermentation, for example, by heating the fermenting potato protein at 80°C for 30 minutes, the free amino acid content can be controlled within a given range. The free amino acid content can be determined using an automated amino acid analysis method.

[0076] There are no particular limitations on the strains used in fermentation, but Aspergillus is preferred. Any strain belonging to the genus Aspergillus can be used as the Aspergillus strain. Examples of strains belonging to the genus Aspergillus include: Aspergillus oryzae, Aspergillus sojae, Aspergillus luchuensis, Aspergillus glaucus, and Aspergillus tamarii, with Aspergillus oryzae being preferred. A single Aspergillus strain can be used, or two or more can be used in combination. The Aspergillus strains can be publicly available strains or strains included in commercially available koji (starter culture) from manufacturers of koji.

[0077] Fermented potato protein can be obtained by adding a starter culture to potato protein and allowing it to ferment. Fermentation conditions such as temperature and time are not particularly limited and can be carried out under conditions commonly used in this field. The preferred fermentation temperature is 20–40°C, more preferably 25–35°C. The preferred fermentation time is 12 hours to 7 days, more preferably 1–4 days.

[0078] The crude protein content in the potato protein composition of this embodiment is preferably 70% by weight or more, preferably 75% by weight or more, and preferably 80% by weight or more in the dried product. If the crude protein content in the dried product is within the above range, there are few impurities, making it preferable as a protein source for feed use. The crude protein content can be determined by a combustion method.

[0079] In addition, the proportion of crude protein from potatoes in the crude protein composition is preferably 90% by weight or more, preferably 95% by weight or more, and preferably 98% by weight or more.

[0080] The moisture content of the potato protein composition in this embodiment is preferably 15% by weight or less, preferably 10% by weight or less, preferably 9% by weight or less, and preferably 8% by weight or less. If the moisture content is within the above range, it is low in moisture, and therefore preferably used as a protein source for feed applications, with excellent shelf life. The moisture content of the potato protein can be measured, for example, using an infrared moisture meter for heat drying quality determination at a temperature of 105°C (atmospheric pressure heat drying method).

[0081] The crude fat content in the potato protein composition of this embodiment is preferably 0.5% by weight or less, preferably 0.2% by weight or less, and preferably 0.1% by weight or less in the dried product. If the crude fat content in the dried product is within the above range, it is preferably used as a protein source for feed applications. The crude fat content can be determined, for example, by the diethyl ether method.

[0082] The potato protein composition of this embodiment preferably has a pH of 4.0 or higher in water, preferably 5.0 or higher, preferably 6.0 or higher, preferably 6.5 or higher, and preferably 7.0 or higher. The pH of the potato protein composition in water is not particularly limited; for example, it can be 10.0 or lower, preferably 9.0 or lower, and preferably 8.5 or lower. If the pH of the potato protein composition in water is within the above range, it is more suitable for use as feed as it improves the feedability and digestibility of aquatic animals.

[0083] It should be noted that the pH of potato protein or a potato protein composition in water can be obtained, for example, by adding water at a ratio of 360g to 40g (dry weight) of potato protein or a potato protein composition, dispersing thoroughly to obtain a dispersion, and then measuring the pH of the resulting dispersion. For example, the pH of fermented potato protein in water can be obtained by adding water at a ratio of 360g to 40g (dry weight) of fermented potato protein, dispersing thoroughly to obtain a dispersion, and then measuring the pH of the resulting dispersion.

[0084] The potato protein composition of this embodiment is particularly suitable as a protein source for animal consumption. Here, "animal" refers to animals including humans, typically aquatic or livestock animals, preferably aquatic animals. Examples of aquatic animals include: fish such as bream, sea bream, salmon, flounder, pufferfish, amberjack, horse mackerel, yellowtail, eel, carp, crucian carp, and rainbow trout; or crustaceans such as shrimp and crab.

[0085] When the potato protein composition of this embodiment is used in a feed composition for aquatic animals, the content of the potato protein composition in the feed composition for aquatic animals is preferably 3% by weight or more, preferably 5% by weight or more, preferably 10% by weight or more, preferably 15% by weight or more, preferably 20% by weight or more, preferably 25% by weight or more, preferably 30% by weight or more, preferably 35% by weight or more, preferably 40% by weight or more. The content of potato protein in the feed composition for aquatic animals is preferably 80% by weight or less, preferably 75% by weight or less, preferably 70% by weight or less in dried matter.

[0086] The potato protein composition of this embodiment preferably includes fermented potato protein, and more preferably includes fermented potato protein obtained by fermenting potato protein (hereinafter also referred to as washed potato protein) that has undergone the above-described washing treatment to reduce the content of potato glycoside alkaloids. Alternatively, the potato protein composition of this embodiment preferably includes washed potato protein and fermented potato protein obtained by fermenting washed potato protein. Alternatively, the potato protein composition of this embodiment can be a mixture of washed potato protein and fermented potato protein obtained by fermenting washed potato protein. The weight ratio of washed potato protein to fermented potato protein in the potato protein composition is, for example, 1:0.1 to 1:10, preferably 1:0.1 to 1:5, and more preferably 1:0.1 to 1:4.

[0087] <Feed Compositions for Aquatic Animals>

[0088] This embodiment is a feed composition for aquatic animals, which contains potato protein, wherein the content of potato glycoside alkaloids in the dried product is less than 100 ppm, and the content of free amino acids in the dried product is more than 4000 ppm and less than 35000 ppm.

[0089] Details about potato protein are as described above.

[0090] The content of potato glycoside alkaloids in the aquatic animal feed composition of this embodiment only needs to be 100 ppm or less in dried matter, preferably 80 ppm or less, more preferably 60 ppm or less, and more preferably 50 ppm or less. By setting the content of potato glycoside alkaloids within the above range, the feed composition for aquatic animals has improved feedability and digestibility, making it more suitable. The content of potato glycoside alkaloids can be determined by liquid chromatography-mass spectrometry (LC / MS).

[0091] The content of potato glycoside alkaloids in the aquatic animal feed composition can be appropriately adjusted by adjusting the content of raw materials containing potato glycoside alkaloids, that is, the content of potato glycoside alkaloids in other potato-derived raw materials other than the aforementioned potato protein composition.

[0092] The free amino acid content in the aquatic animal feed composition of this embodiment is only required to be 4000 ppm or more and 35000 ppm or less in dried matter. Preferably, the free amino acid content in the aquatic animal feed composition in dried matter is 5000 ppm or more, preferably 6000 ppm or more, preferably 7000 ppm or more, preferably 8000 ppm or more, preferably 10000 ppm or more, preferably 12000 ppm or more, preferably 14000 ppm or more, preferably 16000 ppm or more, preferably 18000 ppm or more, preferably 20000 ppm or more. Preferably, the free amino acid content in the aquatic animal feed composition in dried matter is 34000 ppm or less, preferably 33000 ppm or less, preferably 32000 ppm or less, preferably 31000 ppm or less, preferably 30000 ppm or less, preferably 29000 ppm or less, preferably 28000 ppm or less. By setting the free amino acid content within the above range, the feed intake and digestibility of aquatic animals are improved when used as feed, making it more suitable.

[0093] The content of free amino acids in aquatic animal feed compositions can be adjusted not only by adjusting the potato protein composition but also by adjusting the content of raw materials containing free amino acids. The content of free amino acids can be determined using an automated amino acid analysis method.

[0094] The crude protein content of the aquatic animal feed composition of this embodiment is preferably 30% by weight or more, preferably 35% by weight or more, preferably 40% by weight or more, and preferably 45% by weight or more in the dried product. If the crude protein content in the dried product is within the above range, the feed intake and growth rate of aquatic animals are improved when used as feed, making it more suitable. The crude protein content can be determined by the combustion method.

[0095] In addition, the proportion of crude protein from potatoes in the feed composition for aquatic animals is preferably 40% by weight or more, preferably 50% by weight or more, preferably 60% by weight or more, and preferably 70% by weight or more.

[0096] The aquatic animal feed composition of this embodiment further comprises fishmeal. The fishmeal content in the aquatic animal feed composition of this embodiment is preferably 50% by weight or less, preferably 45% by weight or less, preferably 40% by weight or less, preferably 35% by weight or less, preferably 30% by weight or less, preferably 25% by weight or less, preferably 20% by weight or less, and preferably 15% by weight or less. By setting the fishmeal content within the above ranges, a higher fishmeal substitution rate can be achieved.

[0097] The aquatic animal feed composition of this embodiment may further include other raw materials permissible as feed. Other permissible raw materials include all the nutrients required for the growth and development of aquatic animals commonly used in aquaculture, such as: feed organisms like rotifers, brine shrimp, and chlorella; grain flours such as soybean meal, rice flour, defatted soybean meal, corn gluten meal, and wheat flour; lipid components such as soybean oil and fish oil; fish meal, pupal meal, and raw fish paste; bran; α-starch such as α-cassava starch, wheat gluten, sodium caseinate, sodium alginate, sodium polyacrylate, sodium carboxymethyl cellulose, various plant gums, and soybean whey; vitamin mixtures, ascorbic acid, α-tocopherol, and other vitamin sources; calcium dihydrogen phosphate, mineral mixtures, calcium carbonate, and other mineral sources; various protein sources; prebiotic components such as fructooligosaccharides, lactose, oligosaccharides, and galactooligosaccharides; amino acids such as DL-methionine, taurine, L-lysine hydrochloride, and monosodium glutamate, but not limited to these. When using multiple raw materials, there are no particular limitations on the composition ratio of each raw material, which can be appropriately selected by those skilled in the art.

[0098] By feeding aquatic animals with the aquatic animal feed composition of this embodiment, aquatic animal farming can be carried out. Here, the aquatic animals are not particularly limited, and examples include: fish such as yellowtail, sea bream, salmon, flounder, pufferfish, amberjack, horse mackerel, yellowtail, eel, carp, crucian carp, and rainbow trout; crustaceans such as shrimp and crab; and major aquatic reptiles such as turtles and green sea turtles. The aquatic animals are preferably fish or crustaceans, and more preferably yellowtail, sea bream, salmon, or shrimp. The aquatic animal feed composition of this embodiment has particularly high daily feed intake and feed efficiency for aquatic animals, thus enabling efficient breeding (farming) of aquatic animals.

[0099] Example

[0100] The following examples illustrate this implementation in more detail, but this implementation is not limited to these examples. It should be noted that in the examples, "parts" and "%" refer to weight.

[0101] Compositional Analysis

[0102] The contents of crude protein, free amino acids, and potato glycoside alkaloids were analyzed using the following methods.

[0103] (Crude protein: Combustion method)

[0104] The composition analysis of crude protein was commissioned to the Japan Food Analysis Center, a general incorporated foundation, and was determined by combustion method.

[0105] (Free amino acids: Automated amino acid analysis method)

[0106] The composition analysis of free amino acids was commissioned to the Japan Food Analysis Center, a general incorporated foundation, and was performed using an automated amino acid analysis method.

[0107] (Potatoglycoside alkaloids: liquid chromatography-mass spectrometry)

[0108] The compositional analysis of potato glycoside alkaloids was commissioned to the Japan Food Analysis Center, and was performed using liquid chromatography-mass spectrometry.

[0109] <Sample Preparation>

[0110] (Isolation and extraction of potato protein)

[0111] (1) Heat the potato juice obtained by juicing potatoes to cause the potato protein in the potato juice to aggregate.

[0112] (2) Use a dehydrator to dehydrate the aggregated potato protein.

[0113] (3) The dehydrated potato protein was dried using a dryer.

[0114] (4) Use a tabletop grinder (mill) to grind the dried potato protein to obtain the pulverized material.

[0115] The crushed potato protein was used as "unwashed potato protein" in the following experiments.

[0116] (Washing potato protein)

[0117] Using the obtained unwashed potato protein, clean it with acid in a mixing tank according to the following steps.

[0118] Unwashed potato protein was placed in a container, and water was added to prepare a potato protein dispersion with a content of 10% by weight. Sulfuric acid was added while stirring the dispersion to adjust the pH to the range of 3.0–3.5. The temperature of the dispersion was set to room temperature (20–30°C). Less than 10% by weight of dilute sulfuric acid was used as the sulfuric acid.

[0119] Since the pH begins to rise immediately upon the addition of acid, acid is added continuously to maintain the pH within the range of 3.0–3.5. Stirring is continued for approximately 3 hours to confirm that the pH behavior has stabilized. Then, stirring is stopped, and vacuum dehydration is performed to obtain wet potato protein.

[0120] To improve the cleanliness, the washing operation was repeated three more times from the step of preparing a 10% by weight dispersion of potato protein to the step of obtaining wet potato protein. A total of four washing operations were performed.

[0121] After the washing process, add an appropriate amount of sodium hydroxide aqueous solution (less than 5%) to the dispersion obtained by fully dispersing potato protein in water to neutralize the pH of the dispersion to the range of 7.0-7.5. The pH may change during neutralization, so an appropriate amount of sodium hydroxide aqueous solution should be supplied.

[0122] The neutralized dispersion was dehydrated under vacuum, and the resulting wet potato protein was dried at 90-200°C using a dryer until the moisture content reached 5-10%.

[0123] The dried potato protein was used as "washed potato protein" in the following experiments.

[0124] (Fermentation treatment for cleaning potato protein)

[0125] The washed potato protein was ground using a tabletop grinder. After steaming the ground potato protein, 0.02 parts by weight of koji (made by Bioc, for soybean miso) and 3 parts by weight of potato starch were thoroughly mixed and sprinkled onto the mixture for every 100 parts by weight of the steamed potato protein. The mixture was then left to stand at 30°C for 3 days to produce potato protein koji. It should be noted that the potato protein koji was stored frozen.

[0126] Add 25% or 50% of the weight of the aforementioned potato protein starter to the cooked and washed potato protein, mix thoroughly, and ferment at 30°C for 7 days. After fermentation, stop the fermentation by heating at 80°C for 30 minutes. The resulting fermented potato protein, designated as "fermented potato protein," was used in the following experiments.

[0127] (Preparation of the potato protein composition used)

[0128] The unwashed potato protein, washed potato protein, and fermented potato protein were mixed in the proportions shown in Table 1, and the resulting mixture was used as a potato protein composition. The crude protein content, free amino acid content, and potato glycoside alkaloid content of each potato protein composition are shown in Table 1.

[0129] (Preparation of feed compositions for aquatic animals)

[0130] The potato protein composition described above was mixed with other raw materials in the proportions shown in Table 1, and then shaped into pellets with a diameter of approximately 4 mm using a feed pellet mill (manufactured by JIAWANSHUN). After shaping, the pellets were dried using a dryer until the moisture content reached 5-10%, thereby producing the aquatic animal feed compositions of Examples 1-4 and Comparative Examples 1 and 2. Additionally, as a reference example, an aquatic animal feed composition was similarly prepared that did not contain the potato protein composition and used only fishmeal as the protein source. It should be noted that in Examples 1-4 and Comparative Examples 1 and 2, the fishmeal content was reduced, and a potato protein composition with an equal protein content to fishmeal was added to achieve the same level of crude protein. Furthermore, for any weight deficiency caused by the replacement of fishmeal with the potato protein composition, α-starch was added to make the weight equal; any deficiency of ω3 unsaturated fatty acids was adjusted to an equal amount using fish oil; and any deficiency of ash / taurine was adjusted to an equal amount using a commercially available mineral mixture. The crude protein content, crude protein content from potatoes, proportion of crude protein from potatoes in the crude protein of the above-mentioned aquatic animal feed composition, free amino acid content, and potato glycoside alkaloid content are shown in Table 1.

[0131] <Feed efficiency evaluation of samples>

[0132] (Feeding methods)

[0133] Rainbow trout were used as the test fish, and 144L tanks containing 10 test fish were prepared in each embodiment. Freshwater (filtered river water) with a normal supply temperature of approximately 9°C was used for rearing. For all embodiments, after the fish were placed in the tanks, they were pre-fed with the fishmeal formulated feed used in the reference example for approximately one week. After confirming that there was no deviation in feed intake between tanks, the experiment of feeding the aquatic animal feed composition of each embodiment began.

[0134] The experimental diet was administered twice daily until the fish were satiated (until they stopped instantly ingesting food that fell to the bottom of the tank). The amount fed up to this point was defined as the daily feed intake. The feeding trial lasted for 8 weeks. The initial fish weight was measured one week after pre-feeding, and the final fish weight was measured after 8 weeks of feeding. The increase in fish weight from the initial to the final weight was calculated as the total weight gain. Furthermore, the daily feed intake rate (% / day) and feed efficiency (%) were calculated using the following formulas, and the results are shown in Table 1.

[0135] Daily feeding rate (% / day) = Total feed intake (g, wet weight) / ((initial fish weight + final fish weight) / 2) / number of days of rearing × 100

[0136] Feed efficiency (%) = Total weight gain of fish (g, wet weight) / Total feed intake (g, dry weight) × 100

[0137] [Table 1]

[0138]

[0139] As can be clearly seen from Table 1, Examples 1-4, which used potato protein compositions with a potato glycoside alkaloid content of less than 300 ppm and a free amino acid content of 10,000-75,000 ppm, showed equivalent feed intake rates to the reference examples using only fishmeal as the protein source. Furthermore, they demonstrated higher feeding efficiency compared to Comparative Examples 1 and 2, which used potato protein compositions outside this range. Examples 2 and 3, in particular, showed equivalent feeding efficiency to the reference examples using only fishmeal as the protein source. Based on these results, the potato protein compositions and aquatic animal feed compositions of this embodiment are particularly useful as feed ingredients or feeds that can significantly reduce the amount of fishmeal used.

[0140] (Preparation of feed compositions for aquatic animals)

[0141] The potato protein composition consisting solely of the fermented potato protein described above was mixed with other raw materials in the proportions shown in Table 2, and then granulated into pellets with a diameter of approximately 1.6 to 3.5 mm using a pellet mill (12VR-750SDX, manufactured by Alpha Royal). After granulation, the pellets were dried in a dryer set to 60°C for 24 hours, and the powder was removed by sieving, thus producing the aquatic animal feed compositions of Examples 5 to 8. Additionally, as Reference Example 2, an aquatic animal feed composition without the potato protein composition was similarly prepared. The crude protein content, crude protein content from potatoes, the proportion of crude protein from potatoes in the crude protein of the prepared aquatic animal feed compositions, the free amino acid content, and the potato glycoside alkaloid content are shown in Table 2.

[0142] <Feed efficiency evaluation of samples>

[0143] (Feeding methods)

[0144] Red sea bream were used as the test fish, and each example prepared a 500L tank to hold 25 test fish. Filtered seawater at a normal supply temperature of approximately 24°C was used for rearing. For all examples, the fish were pre-fed with commercially available formulated feed (PureGold, manufactured by Nissin Marubeni Feed Co., Ltd.) for one week before being placed in the tanks to ensure uniform average weight. After this, the experiment of feeding the aquatic animal feed composition of each example began.

[0145] The experimental diet was administered twice daily until the fish were satiated (until they no longer ingested food that fell to the bottom of the tank). The amount fed at this point was defined as the daily feed intake. The feeding trial lasted for 10 weeks. The initial fish weight was measured one week after pre-feeding, and the final fish weight was measured after 10 weeks of feeding. The increase in fish weight from the initial to the final weight was calculated as the total weight gain. Furthermore, the daily feed intake rate (% / day) and feed efficiency (%) were calculated using the following formulas, and the results are shown in Table 2.

[0146] Daily feeding rate (% / day) = Total feed intake (g, wet weight) / ((initial fish weight + final fish weight) / 2) / number of days of rearing × 100

[0147] Feed efficiency (%) = Total weight gain of fish (g, wet weight) / Total feed intake (g, dry weight) × 100

[0148] [Table 2]

[0149]

[0150] As can be clearly seen from Table 2, similar to rainbow trout, red sea bream exhibits a high feeding rate when using a potato protein composition with a potato glycoside alkaloid content of less than 300 ppm and a free amino acid content of 10,000 to 75,000 ppm.

[0151] The upper and / or lower limits of the numerical ranges described in this specification can be arbitrarily combined to define the preferred range. For example, the upper and lower limits of the numerical ranges can be arbitrarily combined to define the preferred range, the upper limits of the numerical ranges can be arbitrarily combined with each other to define the preferred range, and the lower limits of the numerical ranges can also be arbitrarily combined with each other to define the preferred range.

[0152] The above provides a detailed description of this embodiment. However, the specific configuration is not limited to this embodiment, and design changes that do not depart from the scope of this disclosure are also included in this disclosure.

[0153] All publications, patents and patent applications cited in this specification are incorporated herein by reference.

Claims

1. A potato protein composition, wherein, The content of potato glycoside alkaloids in the dried product is below 300 ppm. The content of free amino acids in the dried matter is above 10,000 ppm and below 75,000 ppm.

2. The potato protein composition according to claim 1, wherein, The crude protein content in the dried product is above 70% by weight.

3. The potato protein composition according to claim 1 or 2, wherein, The crude protein in the potato protein composition comprises more than 90% by weight crude protein from potatoes.

4. The potato protein composition according to claim 1 or 2, wherein it contains fermented potato protein.

5. A feed composition for aquatic animals, comprising the potato protein composition of claim 1 or 2.

6. A feed composition for aquatic animals, comprising potato protein, wherein, The content of potato glycoside alkaloids in the dried product is less than 100 ppm. The content of free amino acids in the dried product is above 4000 ppm and below 35000 ppm.

7. The aquatic animal feed composition according to claim 6, wherein, The crude protein content in the dried product is above 30% by weight.

8. The aquatic animal feed composition according to claim 6 or 7, wherein, The crude protein in the feed composition for aquatic animals shall be more than 40% by weight of crude protein from potatoes.

9. The aquatic animal feed composition according to claim 6 or 7, further comprising fishmeal, wherein, The fishmeal content is less than 50% by weight.

10. The aquatic animal feed composition according to claim 9, wherein, The fishmeal content is less than 30% by weight.

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