Grain husks, gluten feed, method for producing grain husks, method for producing gluten feed, feed for raising insects, and method for raising insects

Abstract

To solve problems for example, since a cereal grain coat and a gluten feed are formed of mainly, a fiber, and their nutrition values are low, therefore they cannot be used except for use as animal feed or fuel, and when the coat or the gluten feed is used as an animal feed, relative to other animal feed raw materials, there is no example in which the coat or the gluten feed exhibits a significant effect and there is no method in which a utility value of the coat or the gluten feed is enhanced.SOLUTION: There is provided a cereal grain coat and / or a gluten feed obtained by wet milling, the cereal grain coat and / or the gluten feed comprising a pH in a weak acid acidic area or in a neutral area. There are also provided: an insect animal feed including the cereal grain coat and / or the gluten feed; and an insect rearing method using the same insect animal feed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to grain husks obtained by processing grains by wet milling, gluten feed, a method for producing grain husks, a method for producing gluten feed, feed for raising insects, and a method for raising insects. [Background technology]

[0002] Wet milling, also known as wet grinding, is a method for separating grains, primarily corn, into their constituent components, such as husks, germ, protein, and starch. In wet milling, grains are soaked in an acidic solution, swelled, and then ground to promote the separation of their constituents. The husks, also known as bran, are a by-product of grain wet milling and are used as livestock feed and fuel. Gluten feed is made by mixing the husks with the liquid in which grains have been soaked, also known as steep liquor, and then dehydrating and / or drying them. Because gluten feed has a higher nutritional value than the husks, it is primarily used as livestock feed.

[0003] Like husks and gluten feed, proteins obtained by wet milling are called gluten meal and are used as livestock feed. When a sulfite solution is used in wet milling, sulfites such as sulfur dioxide remain in the gluten meal. Therefore, heat-treated corn gluten meal (sulfur dioxide content less than 30 ppm, protein content 50 to 99% by weight on a dry weight basis) for human food or feed use is known, in which sulfites have been removed from gluten meal (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4750901 Summary of the Invention [Problem to be solved by the invention]

[0005] According to Patent Document 1, sulfites are believed to exist mainly in a bound form in gluten meal. However, it is not known whether acids such as sulfites exist in grain husks or gluten feeds whose main component is husks.

[0006] Because grain husks and gluten feed are primarily composed of fiber, they have low nutritional value and have no uses other than as feed or fuel. Even when used as animal feed, there have been no examples of significant benefits compared to other feed ingredients, and no valuable uses for grain husks or gluten feed have been found.

[0007] In recent years, insects have been attracting attention as a source of animal protein for food and animal feed. However, when insects are raised using grain husks or gluten feed as feed, they grow very little, and are therefore insufficient as feed for insect rearing. [Means for solving the problem]

[0008] The present invention relates to cereal husks obtained by wet milling, the pH of which is in the weakly acidic or neutral region. Another invention relates to a gluten feed comprising cereal husks obtained by wet milling and a grain soaking liquid obtained by wet milling, the pH of which is in the weakly acidic or neutral region.

[0009] Furthermore, in the case of the grain husks or gluten feed of the present invention, the water in which the grain husks or gluten feed are soaked has a pH of 4 to 8. Furthermore, when the grain husks or gluten feed are soaked in water with a weight four times that of the grain husks or gluten feed, the electrical conductivity of the water may be less than 10 mS / cm, for example, 2 to 9 mS / cm. The grain in the present invention may be corn.

[0010] The present invention provides a method for producing cereal husks, which includes an adjusting step of increasing the pH and / or decreasing the electrical conductivity of the husks. The method for producing cereal husks of the present invention may include a soaking step of soaking grains in an acidic solution to obtain a soaked product, a first separation step of separating a grain soaking liquid and a solid material containing the germ and husks of the grain from the soaked product, a second separation step of separating the germ and the husks from the solid material, and an adjusting step of increasing the pH and / or decreasing the electrical conductivity of the husks.

[0011] Furthermore, the present invention provides a method for producing gluten feed, comprising an adjusting step of increasing the pH and / or decreasing the electrical conductivity of one or more selected from the gluten feed. The method for producing gluten feed of the present invention may comprise: a soaking step of soaking grains in an acidic solution to obtain a soaked product; a first separation step of separating a grain soaking liquid and a solid material containing the germ and husks of the grain from the soaked product; a second separation step of separating the germ and the husks from the solid material; a mixing step of mixing the husks with the grain soaking liquid to obtain gluten feed; and an adjusting step of increasing the pH and / or decreasing the electrical conductivity of one or more selected from the grain soaking liquid, the husks, and the gluten feed.

[0012] In the method for producing grain husks or the method for producing gluten feed of the present invention, the adjusting step may be a step of mixing with an alkaline solution or a step of washing with an alkaline solution and / or water.

[0013] The present invention provides a feed for growing insects, comprising cereal husks or gluten feed. The present invention further provides a feed for raising insects, comprising wheat bran. The insects may be beetles. The present invention also provides a method for raising insects on grain husks or gluten feed. The insects may be beetles. [Effects of the Invention]

[0014] The pH of grain husks and gluten feed obtained by wet milling is acidic, but if the pH is adjusted to a slightly acidic or neutral range, the growth of animals such as insects can be significantly promoted. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows the results of insect rearing in this example, in which different letters indicate a significant difference of p<0.01 as determined by a statistical test (One-way ANOVA with Bonferroni correction). [Figure 2] 1 shows the results of rearing insects in this example. [Figure 3] 1 shows the results of rearing insects in this example, with asterisks indicating that a significant difference was found between the example and the comparative example by statistical testing (One-way ANOVA with Dunnett's multiple comparisons test). DETAILED DESCRIPTION OF THE INVENTION

[0016] The following describes an embodiment of the present invention, but the present invention is not limited to the following embodiment.

[0017] The present invention relates to grain husks obtained by wet milling, which have a pH in the weakly acidic to neutral range.

[0018] Wet milling, also known as wet grinding, was developed as a method for producing starch from grains with hard outer skins (or pericarp), such as corn and rice. Wet milling is primarily used in corn processing, where the grain is soaked in an acidic solution to swell, the soaking liquid is separated and removed, and the swollen grain is ground to separate the grain into its outer skin, germ, protein, and starch.

[0019] The grain in the present invention is preferably corn. The corn used for wet milling is preferably dent corn, because dent corn has a higher starch content than other types of corn.

[0020] Here is a specific example of corn wet milling: Corn is soaked in a 0.1 to 0.3% by volume aqueous solution of sulfurous acid at a temperature of 45 to 55°C for 30 to 48 hours. After that, solid-liquid separation is performed to obtain a solid content consisting mainly of swollen corn and a soaking liquid from which the solid content has been removed.

[0021] The swollen corn is crushed and then separated into a liquid and a solid portion. The solid portion consists of the germ and husk, and the husk is obtained by classification such as sieving. The corn husk, also known as corn bran, is primarily composed of arabinoxylan, a type of hemicellulose. The liquid portion remaining after the germ and husk are separated is primarily composed of protein and starch.

[0022] The steeping liquid is called steep liquor. Steep liquor can also refer to steeping liquid concentrated to about 50% solids. Steep liquor contains nucleic acids such as inositol and their decomposition products, water-soluble vitamins, amino acids, etc. Steep liquor is mixed with husks, and then dehydrated and dried to produce gluten feed. In other words, gluten feed is made by mixing grain husks obtained mainly from wet milling with grain steeping liquid obtained from wet milling.

[0023] The cereal husks and / or gluten feed obtained by wet milling may be washed with water, but the pH is in the acidic range. Here, "the pH of the cereal husks and / or gluten feed is in the acidic range" means that the pH of the water in which the cereal husks and / or gluten feed are soaked is in the acidic range, and specifically, the pH may be less than 3.9. The water is preferably distilled water, ion-exchanged water, or pure water, but tap water may also be used. The pH of the cereal husks and / or gluten feed can be determined by soaking the cereal husks and / or gluten feed in water that is 3 to 100 times their weight and measuring the pH of the supernatant.

[0024] The pH of the cereal husks and / or gluten feed of the present invention is in the weakly acidic or neutral range, and is at least higher than the pH of conventional cereal husks and / or gluten feeds. Specifically, the pH of the distilled water in which the cereal husks and / or gluten feed are soaked is 4 or higher, preferably 4.1 or higher, 4.2 or higher, 4.3 or higher, 4.4 or higher, or 4.5 or higher, and is preferably in the range of 4.1 to 8.0, more preferably 5.0 to 7.5.

[0025] The grain husks and / or gluten feed of the present invention are preferably soaked in water with a lower electrical conductivity than conventional grain husks and / or gluten feeds. This is because the electrolytes contained in the grain husks and / or gluten feed are lost during the washing process described below. When conventional gluten feeds are soaked in four times their weight of water, the electrical conductivity of the water is 12 to 13 mS / cm. When the grain husks and / or gluten feed of the present invention are soaked in four times their weight of water, the electrical conductivity of the water is preferably less than 10 mS / cm, more preferably 2 to 9 mS / cm. Examples of water that can be used include tap water, distilled water, ion-exchanged water, and pure water.

[0026] Another aspect of the present invention provides a method for producing grain husks, comprising a soaking step of soaking grains in an acidic solution to obtain a soaked product, a first separation step of separating the soaked product into a grain soaking solution and a solid mixture containing the grain germ and husks, a second separation step of separating the germ and husks from the solid mixture, and an adjustment step of increasing the pH of the husks and / or decreasing the electrical conductivity of the husks. Here, the soaking step, the first separation step, and the second separation step are included in wet milling, and the solid refers to swollen grains, such as the swollen corn described above.

[0027] The adjusting step is a step of increasing the pH of the exine shell, preferably a step of adjusting the pH of the exine shell to a weakly acidic or neutral region. Another adjusting step is a step of decreasing the electrical conductivity of the exine shell, preferably a step of adjusting the electrical conductivity of the water when the exine shell is immersed in water four times its weight to less than 10 mS / cm. Hereinafter, electrical conductivity refers to the electrical conductivity of the water when the object to be measured is immersed in water four times its weight.

[0028] Yet another aspect of the present invention provides a method for producing gluten feed, comprising a soaking step of soaking grains in an acidic solution to obtain a soaked product, a first separation step of separating the soaked product into a grain soaking liquid and a solid mixture containing the grain germ and husks, a second separation step of separating the germ and husks from the solid mixture, a mixing step of mixing the husks with the grain soaking liquid, and an adjusting step. Here, the soaking step, the first separation step, and the second separation step are included in wet milling, and the solid refers to swollen grains, such as the swollen corn described above.

[0029] The method for producing gluten feed of the present invention may be one or more selected from the following: a method in which the pH of the husks and / or grain soaking liquid is increased before mixing, preferably to a weakly acidic or neutral range, and then the husks and grain soaking liquid are mixed to obtain gluten feed; a method in which the husks and grain soaking liquid are mixed to obtain gluten feed, and then the pH of the gluten feed is increased, preferably to a weakly acidic or neutral range; a method in which the electrical conductivity of the husks and / or grain soaking liquid before mixing, preferably to a value less than 10 mS / cm, and then the husks and grain soaking liquid are mixed to obtain gluten feed; and a method in which the electrical conductivity of the gluten feed is decreased after obtaining the gluten feed, preferably to a value less than 10 mS / cm. The husks are preferably dehydrated and / or dried either directly or after mixing with the grain soaking liquid to obtain dried husks or gluten feed.

[0030] The adjustment process for grain husks and / or gluten feed involves increasing the pH and / or decreasing the electrical conductivity of the acidic grain husks and / or gluten feed, and the method is not limited. Specific examples include heating to remove remaining components such as sulfur dioxide, mixing with an alkaline solution, and washing with an alkaline solution and / or water. The adjustment process can bring the pH of the grain husks and / or gluten feed into the neutral or weakly acidic range. Furthermore, the adjustment process can bring the electrical conductivity of the grain husks and / or gluten feed to less than 10 mS / cm.

[0031] Among these, the method of mixing with an alkaline solution and the method of washing with an alkaline solution and / or water are advantageous over the method of heating in that the components are less likely to be denatured and the energy costs are low. Examples of alkaline solutions include aqueous sodium hydroxide, aqueous potassium hydroxide, aqueous calcium hydroxide, and aqueous ammonia.

[0032] Specifically, the method of washing with an alkaline solution and / or water may be a method of adding an alkaline solution and / or water to the cereal husks and / or gluten feed, preferably stirring, and separating the alkaline solution and / or water from the cereal husks and / or gluten feed. Examples of water that can be used include tap water, distilled water, ion-exchanged water, and pure water.

[0033] The grain steeping liquid adjustment step involves increasing the pH of the grain steeping liquid, i.e., adjusting the pH of the acidic grain steeping liquid to a weakly acidic or neutral range, and the method is not limited thereto. Specific examples include neutralization with an alkali such as sodium hydroxide, potassium hydroxide, or calcium hydroxide.

[0034] Furthermore, the present invention provides an insect feed containing grain husks and / or gluten feed, and a method for raising insects using the insect feed. Here, the insects preferably used are insect species that can be easily and efficiently raised or insect species for which artificial rearing techniques have been established.

[0035] Specifically, insects belonging to the orders Diptera, Coleoptera, and Orthoptera are used. Examples of Diptera include the house fly (Musca domestica) of the family Muscidae, the flesh fly (Sarcophaga peregrina) of the family Sarcophagidae, the citrus fly (Tetradacus tsuneonis), the oriental fruit fly (Strumeta dorsalis), and the melon fly (Bactrocera cucurbitae / Zeugodacus cucurbitae) of the family Tephritidae, and the American soldier fly (Hermetia illucens) and the black soldier fly (Ptecticus tenebrifer) of the family Stratiomyiidae.

[0036] Examples of beetles, that is, in the order Coleoptera, include so-called mealworms such as Tenebrio obscurus, Tenebrio molitor, and Zophobas atratus, which belong to the superfamily Tenebrionoidea and family Tenebrionidae, and examples of beetles in the order Orthoptera include Gryllus bimaculatus and Acheta domesticus, which belong to the family Grylloidea. The insects raised on the insect feed of the present invention are preferably larvae of beetles called mealworms. [Example]

[0037] The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0038] 1. Production of Corn Husk and / or Gluten Feed (1)

[0039] One cubic meter of an aqueous solution containing 0.1% by weight of sulfurous acid was added to 1 ton of dried corn (dent corn), and the corn was soaked at 50°C for 35 hours. The soaking solution was separated from the solids, and the solids were crushed. The husks were separated from the germ using a screen and washed with water to obtain corn husks. 30 mL of ion-exchanged water was added to 1 g of the corn husks, and the husks were soaked at room temperature for 1 hour. The pH of the supernatant obtained by centrifugation was measured and found to be 3.9.

[0040] Furthermore, corn husks were mixed with steep liquor concentrated to approximately 50% solids, and the mixture was dehydrated and dried to obtain gluten feed. 30 mL of ion-exchanged water was added to 1 g of the gluten feed, and the mixture was left to soak at room temperature for 1 hour. The pH of the supernatant obtained by centrifugation was measured and found to be 3.9.

[0041] The pH of this corn husk or gluten feed was adjusted by adding 161 mL of 1N aqueous sodium hydroxide solution and 100 mL of distilled water to 200 g of corn husk or gluten feed, mixing the mixture, soaking it at 50°C for 12 hours, and drying it at 70°C. 30 mL of ion-exchanged water was added to 1 g of the corn husk or gluten feed, and the mixture was allowed to soak at room temperature for 1 hour. The pH of the supernatant obtained by centrifugation was measured and found to be 7.0.

[0042] 2. Production of corn husk and / or gluten feed (2) The acidic corn husks were washed with running tap water. 300 mL of 6N sodium hydroxide solution was added to 1 L of steep liquor (pH 3.9) and the pH was measured, which was found to be 6.5. The precipitate was then removed by centrifugation. The corn husks and steep liquor (2) were mixed and dried to produce gluten feed. The gluten feed was immersed in distilled water for 1 hour, and the pH of the supernatant obtained by centrifugation was measured, which was found to be 5.1. The electrical conductivity was measured, which was found to be 5.7 mS / cm.

[0043] 3. Production of corn husk and / or gluten feed (3) Gluten feed that showed a pH of 3.9 was mixed with four times its weight of distilled water and soaked in it. After leaving it for one hour, it was centrifuged and the supernatant was discarded. This counted as one wash, and washing was carried out four times in total. The pH and electrical conductivity of the supernatant were measured at room temperature after each wash. The measurement results are shown in Table 1. Compared to before washing, the pH of the gluten feed after washing increased, and the electrical conductivity of the supernatant of the distilled water in which it was soaked decreased.

[0044] [Table 1]

[0045] 4. Insect rearing test using gluten-containing feed (1) A rearing test was conducted using larvae of the beetle mealworm (T. molitor). The comparative example used gluten feed with a pH of 3.9, while the example 1 used gluten feed with a pH of 7, produced by the method described in 1 above. The example 2 used a 1:1 weight ratio mixture of the gluten feed from example 1 and wheat bran. Twenty mealworm larvae (average weight per individual: 12.6 mg) were added to 10 g of each feed and reared at 25°C for 28 days. The weights per individual measured at the start and after 28 days of rearing are shown in Figure 1. The comparative example showed significantly lower growth than the wheat bran (positive control), while the example 1 showed growth equivalent to that of the wheat bran. Furthermore, the example 2 showed significantly more favorable growth than the wheat bran (positive control). The survival rate was over 90% under all conditions.

[0046] 5. Insect rearing test using gluten-containing feed (2) A rearing test was conducted using larvae of the beetle mealworm (T. molitor). In the example, gluten feed produced by the method described in 2. above was used as insect rearing feed, while wheat bran served as a control. Twenty mealworm larvae (average weight per individual: 8.3 mg) were added to 10 g of each feed, and reared at 25°C for 28 days. Measurements of the weight per individual at the start and after 28 days of rearing are shown in Figure 2. The growth of the example was comparable to that of the positive control (wheat bran), with no significant difference. The survival rate was 100% in both cases. As shown in Figure 1, larvae reared on unadjusted gluten feed showed significantly lower growth than those on wheat bran, demonstrating that the example promotes larval growth compared to the unadjusted gluten feed.

[0047] 6. Insect rearing test using gluten-containing feed (3) A rearing test was conducted using larvae of the beetle mealworm (T. molitor). In the examples, gluten feed produced by the method described in 4. above was used as insect rearing feed, while in the comparative example, gluten feed with a pH of 3.9 was used. Twenty-two mealworm larvae (average weight per individual: 5.7 mg) were added to 10 g of each feed, and the larvae were reared at 25°C for 28 days. The weights per individual measured at the start and after 28 days of rearing are shown in Figure 3. Larval growth was significantly promoted by using gluten feed that had been washed one to four times. Larval growth was particularly maximized when gluten feed that had been washed three times (soaking water pH 4.2, electrophoretic mobility 3.2 mS / cm) was used.

[0048] The survival rate of the larvae during the test period is shown in Table 2. By using gluten feed that had been washed one to four times, the survival rate of the larvae was improved compared to the comparative example.

[0049] [Table 2]

Claims

1. It is a feed for raising beetles that contains gluten feed, The gluten feed contains corn husks obtained by wet milling and corn steeping liquid obtained by wet milling, and when steeped in 4 times its weight of distilled water, the pH of the distilled water after steeping is 4 to 8. Food for raising beetles.

2. 2. The beetle rearing feed according to claim 1, wherein when the gluten feed is soaked in four times its weight of distilled water, the electrical conductivity of the distilled water after soaking is less than 10 mS / cm.

3. The feed for raising beetles according to claim 1 or 2, further comprising wheat bran.

4. A method for producing the feed for raising beetles according to any one of claims 1 to 3, The corn husk or gluten feed is prepared by: The adjusting step removing sulfur dioxide from the corn husks or gluten feed; mixing the corn husks or the gluten feed with an alkaline solution; or washing the corn husks or gluten feed with an alkaline solution and / or water; Manufacturing method.

5. A method for producing the feed for raising beetles according to any one of claims 1 to 3, The method includes adjusting the pH of the corn steep liquor to increase the pH and / or decrease the electrical conductivity.

6. A method for raising beetles, comprising raising beetles using the feed for raising beetles according to any one of claims 1 to 3.

Images