Method for treating cotton seeds

Abstract

The present invention makes it possible to provide a method for treating cotton seeds, in which cotton seeds are fermented in the presence of microorganisms to reduce the gossypol contained in the cotton seeds. Natto bacteria may be used as the microorganisms. The cotton seeds may be heated in an autoclave at 121°C for 10 minutes, inoculated with the natto bacteria, and cultured at 40°C for 24 hours. The cotton seeds may furthermore be aged at 4°C for 10 days. Furthermore, the cotton seeds may be dried at 80°C for 2 hours.

Description

Cotton seed processing methods

[0001] Embodiments of the present disclosure relate to a method for treating cotton seeds.

[0002] The cotton genus (Gossypium) is a plant in the Malvaceae family and is one of the most important fiber crops. Cotton, the fiber part of cotton, is the seed attached to the cotton seed. The cotton seed that remains after cotton is harvested contains high-quality oil and protein, and is rich in vitamins and minerals, making it particularly excellent as a nutritional source. If current global cotton production is combined, cotton seed could potentially provide food for approximately 500 million people.

[0003] On the other hand, cottonseed contains the toxic compound gossypol, a terpenoid aldehyde unique to the Gossypium genus. The detailed mechanism of gossypol intoxication is unclear, but possible causes include apoptosis of spermatocytes, inhibition of intercellular communication at gap junctions, generation of reactive oxygen species, increased intracellular calcium concentration, depolarization of mitochondrial membranes, increased proton permeability of the cell membrane, and inhibition of protein kinase C activity.

[0004] Therefore, as one of the countermeasures against food shortages, it is expected that a method for processing cottonseeds that can reduce and detoxify gossypol in cottonseeds will be developed. Patent Document 1 discloses a method for decomposing gossypol by irradiating it with far infrared rays.

[0005] Japanese Patent Application Publication No. 01-300878

[0006] One object of one embodiment of the present invention is to provide a method for treating cottonseeds that reduces the amount of gossypol contained in the cottonseeds.

[0007] As a result of extensive research to achieve the above-mentioned object, the inventors discovered that the gossypol content of cotton seeds can be reduced by fermenting the seeds in the presence of microorganisms, and thus completed the present invention.

[0008] One embodiment of the present invention can provide a method for treating cotton seeds, in which cotton seeds are fermented in the presence of a microorganism to reduce gossypol contained in the cotton seeds.

[0009] Bacillus subtilis natto may be used as the microorganism. Cotton seeds may be heated in an autoclave at 121°C for 10 minutes, and the Bacillus subtilis natto may be inoculated into the cotton seeds, followed by culturing at 40°C for 24 hours. The cotton seeds may then be aged at 4°C for 10 days. The cotton seeds may then be dried at 80°C for 2 hours.

[0010] According to one embodiment of the present invention, there is provided a method for treating cottonseed to reduce gossypol in the cottonseed.

[0011] 1A and 1B are HPLC charts of cottonseed extracts according to examples of the present invention, cottonseed extracts according to comparative examples of the present invention, and untreated cottonseed extracts, respectively.

[0012] Hereinafter, a method for processing cottonseeds according to one embodiment of the present invention will be described in detail. However, the method for processing cottonseeds according to one embodiment of the present invention should not be construed as being limited to the following embodiments and examples.

[0013] In the method for treating cottonseeds according to this embodiment, cottonseeds are fermented in the presence of microorganisms to reduce the amount of gossypol contained in the cottonseeds.

[0014] The cottonseed varieties according to the present embodiment can be broadly divided into four types: upland cotton G. hirsutum L., Upland cotton, Asian cotton G. herbaceum Oliver, Sea island cotton G. barbadense L., Sea island cotton, and Nanjing cotton G. nanking Meyen. The cottonseed according to the present embodiment is preferably the seed of Asian cotton G. herbaceum Oliver. However, the cottonseed according to the present embodiment is not limited thereto, and may be the seed of any species of the genus Gossypium in the family Malvaceae.

[0015] The cottonseed according to the present invention may be sterilized before being inoculated with the microorganism, or may be heated in an autoclave at 121° C. for 10 minutes.

[0016] In this embodiment, the microorganisms used for fermentation are not particularly limited. Examples of microorganisms that can be used include fungi, bacteria, and archaea. Examples of bacteria that can be used for fermentation include gram-positive cocci, such as Ruminococcus flavefaciens SIJPESTEIJN, 1948, or Ruminovoccus albus HUNGATE, 1957. Examples of bacteria that can be used for fermentation include gram-negative cocci, such as Lampropedia hyalina SCHROETER, 1886. Examples of bacteria that can be used for fermentation include gram-positive rods, such as Eubacterium clulosolvens HOLDEMAN and MOORE, 1972. The bacteria used for fermentation may be, for example, spore-forming bacilli, such as Bacteroides succinogenes HUNGATE, 1950 or Butyrivibrio fibrisolvens BRYANT and SMALL. The bacteria used for fermentation may be, for example, the gut symbiotic protists of lower termites, such as species belonging to the phyla Parabasalia and Preaxostylae. The bacteria used for fermentation may be, for example, Bacillus subtilis, such as Bacillus subtilis var. natto.

[0017] In the cottonseed processing method according to this embodiment, cottonseeds are fermented in the presence of microorganisms. The cottonseed processing method may involve, for example, inoculating sterilized cottonseeds with Bacillus subtilis natto and culturing them at 40°C for 24 hours. The cultured cottonseeds may be further aged at 4°C for 10 days. The aged cottonseeds may be further dried at 80°C for 2 hours. However, the conditions for fermenting cottonseeds in the presence of microorganisms are not particularly limited. In the cottonseed processing method according to this embodiment, gossypol contained in the cottonseeds can be reduced by fermenting the cottonseeds in the presence of microorganisms.

[0018] Cottonseeds contain up to about 36 mg of gossypol per gram. In this embodiment, the gossypol content in cottonseeds may be evaluated by measuring the gossypol content in a cottonseed extract. Ground cottonseeds may be used as the material for the cottonseed extract. Ground cottonseeds may be obtained by removing the outer fibers and grinding the cottonseeds in a mortar. Since gossypol is stable in acetone, the cottonseed extract may be prepared by extracting ground cottonseeds with acetone. For example, the cottonseed extract may be prepared by adding 50 ml of acetone to 1 g of ground cottonseeds and heating the sample in a sealed sample container in a water bath at 100°C for 20 minutes. However, the cottonseed extract is not limited to this method; the extraction method is not particularly limited as long as the cottonseed extract reflects the gossypol content in the cottonseeds.

[0019] The content of gossypol in the cottonseed extract may be measured using HPLC (high performance liquid chromatography). The column may be, for example, an octadecyl-group chemically bonded column used in reversed-phase chromatography. The gossypol content in the cottonseed extract may be detected by measuring the refractive index at a wavelength of 254 nm. The content of gossypol in the cottonseed extract may be calculated from a calibration curve prepared using a gossypol standard. However, the method is not limited thereto, and the method for measuring the gossypol content is not particularly limited as long as gossypol in the cottonseed extract can be separated and quantified.

[0020] An example of the method for processing cottonseeds according to this embodiment is shown below, but this description is merely an example and is not intended to be limiting.

[0021] Example: 50 g of cottonseed was heat sterilized at 121°C for 10 minutes in an autoclave (ST200, Yamato Scientific Co., Ltd.). Approximately 20 grains of natto were removed from a commercially available natto pack (Okame Natto Mini Grains, Takano Foods Co., Ltd.). The hot sterilized cottonseed was transferred into the natto pack and mixed thoroughly. The natto pack was then covered with a lid, and the cottonseed was fermented at 40°C for 24 hours in a soft incubator (SLI-400, Tokyo Rikakikai Co., Ltd.). The fermented cottonseed was aged in its original pack in a refrigerator (Biomedical Freezer MDF-U539-PJ, Panasonic) at 5°C for 10 days. The aged cottonseed was dried at 80°C for 2 hours in a high-temperature incubator (Ajisai, Isuzu Manufacturing Co., Ltd.) to obtain the cottonseed of this example.

[0022] <Comparative Example> Two to three cotton seeds were heat sterilized in an autoclave (ST200, Yamato Scientific Co., Ltd.) at 121°C for 10 minutes. The sterilized cotton seeds were dried at 80°C for 2 hours using a high-temperature incubator (Ajisai, Isuzu Manufacturing Co., Ltd.) to obtain cotton seeds for the comparative example.

[0023] <Preparation of Cottonseed Extract> Cottonseed extracts were prepared by extracting untreated, Example, or Comparative cottonseed with acetone. Untreated, Example, or Comparative cottonseed was ground in a mortar to obtain cottonseed powder. 0.1 g of each resulting cottonseed powder was placed in a vial (Mighty Vial, Maruem), and 5 ml of acetone (Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The cottonseed powder was extracted with acetone by heating in a 100°C water bath for 20 minutes. After cooling with water, the extract was passed through a 0.45 μm filter (Commonice Filter W (aqueous) 0.45 μm, Nakalai Tesque (Merck)) to obtain cottonseed extracts for the untreated, Example, and Comparative cottonseed.

[0024] <Measurement of Gossypol Content> Using HPLC, gossypol was detected and quantified in the untreated cottonseed extracts of the Examples and Comparative Examples. A chart and calibration curve using a gossypol standard were used for detection and quantification. 3.0 mg of gossypol standard (G5874, Fujifilm Wako Pure Chemical Industries, Ltd. (LKT)) was dissolved in 3 ml of acetone to prepare a 0.1% standard stock solution, from which 0.01%, 0.001%, 0.005%, and 0.0001% standard solutions were prepared. The calibration curve for gossypol was created by measuring each standard solution three times using an HPLC system and averaging the area values ​​obtained. Gossypol was detected at 3.8 minutes as a clear peak sufficiently separated from the void peak around 2 minutes.

[0025] The HPLC detection conditions are as follows: Column: 5C18-MS-II (4.6 ID x 150 mm), Mobile phase: Methanol: 0.5% acetic acid aqueous solution = 9:1, Flow rate: 1 ml / min, Column temperature: 40°C, Detection wavelength: 254 nm

[0026] Figure 1 is an HPLC chart of a cottonseed extract according to an example of the present invention. Figure 2 is an HPLC chart of a cottonseed extract according to a comparative example of the present invention. Figure 3 is an HPLC chart of an untreated cottonseed extract. Table 1 shows the area values ​​measured three times using an HPLC device, as well as the concentration and content of gossypol in the cottonseed extract.

[0027]

[0028] As shown in Figure 1, no gossypol peak was detected in the cottonseed extract according to the example of the present invention. On the other hand, as shown in Figure 2 and Table 1, the cottonseed extract according to the comparative example of the present invention contained 8% of the gossypol content compared to the untreated cottonseed extract.

[0029] As described above, it was confirmed that in the cottonseed processing method according to this embodiment, gossypol contained in cottonseed is removed to below the detection limit by fermenting the cottonseed in the presence of microorganisms.

Claims

1. A method for treating cotton seeds, which comprises fermenting the cotton seeds in the presence of microorganisms to reduce gossypol contained in the cotton seeds.

2. The method for treating cotton seeds according to claim 1, wherein Bacillus natto is used as the microorganism.

3. The method for treating cotton seeds according to claim 2, wherein the cotton seeds are heated at 121°C for 10 minutes in an autoclave, inoculated with the Bacillus natto, and cultured at 40°C for 24 hours.

4. The method for treating cotton seeds according to claim 3, further comprising aging at 4°C for 10 days.

5. The method for treating cotton seeds according to claim 4, further comprising drying at 80°C for 2 hours.

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