JP2008285456A - Extraction method and extraction apparatus of collagen, production method and production apparatus of hydroxyapatite, and collagen-containing aqueous extract and hydroxyapatite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for obtaining collagen and hydroxyapatite. <P>SOLUTION: Subcritical water is prepared from the water in a water tank 1 by means of a high-pressure pump 2 and an electric furnace 4, and is sent to an extraction pipe 7 filled with fish scales via a valve 5a. A by-pass 10 is provided, in addition to the extraction pipe 7, for bypassing the subcritical water until feeding of the subcritical water gets stabilized, and a nitrogen gas cylinder 15 is connected for preventing vaporization of the subcritical water caused by pressure decrease at the time of introduction of the subcritical water into the extraction pipe 7 at the initial stage of operation of the apparatus. Collagen is extracted with the subcritical water in the extraction pipe 7. A filter 8 made of steel wool is provided near the exit of the extraction pipe 7 in order to prevent discharge of solid contents. A cooling pipe 11 for cooling the subcritical water after extraction is connected to the lower part of the extraction pipe 7 via a valve 5d. The aqueous extract discharged from the cooling pipe 11 is steadily discharged outside via a control valve 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and apparatus for extracting collagen, a method and apparatus for producing hydroxyapatite, a collagen-containing aqueous extract and hydroxyapatite, and more particularly, a method for extracting collagen using subcritical water or supercritical water, and The present invention relates to a hydroxyapatite production apparatus, a hydroxyapatite production apparatus and production method, and a collagen-containing aqueous extract and hydroxyapatite obtained by this method.

  Gelatin is an animal protein that is widely used for food, medicine, photography, industry, cosmetics, and the like, and is generally produced by hydrolyzing animal skin whose main component is collagen. Gelatin used for these purposes was often prepared from cowhide before the BSE problem was raised, but nowadays it is often made from materials other than cowhide. Under such circumstances, marine animals have begun to attract attention as a new collagen source. Among them, fish scales discarded in the market and fishery processing plants are becoming established as an effective collagen source (for example, Patent Document 1).

  The main components of fish scale are type I collagen and hydroxyapatite, and the ratio varies depending on the fish species, but it is about 1: 1 for Japanese sardines. Hydroxyapatite contained in fish scales with collagen is used as a base for powdered products such as foundations as cosmetic materials. Hydroxyapatite is also used as an artificial tooth root, artificial bone and the like because it has excellent biocompatibility and bone affinity. In addition, since it has an ion exchange function and a function of adsorbing and removing dirt on the tooth surface, it is also used in a dentifrice due to a synergistic effect with the surfactant.

  There are roughly two methods for preparing gelatin and hydroxyapatite from fish scales. One is a method in which fish scale and diluted hydrochloric acid are stirred for several hours to hydrolyze the remaining collagen as an insoluble matter because hydroxyapatite dissolves in diluted hydrochloric acid or the like. The other is a method in which fish scales are immersed in hot water for several hours and hydrolyzed to obtain a hydroxyapatite precipitate and a gelatin solution (Patent Document 1, Non-Patent Document 1).

  However, the above-mentioned method of dissolving hydroxyapatite in dilute hydrochloric acid requires neutralization of dilute hydrochloric acid in the post-treatment process, and the method of immersing fish scales in hot water for several hours requires a long time for the treatment. Therefore, a simpler method for producing collagen and hydroxyapatite is desired.

On the other hand, high-pressure hot water extraction method (subcritical water extraction method) using high-pressure hot water has begun to attract attention in recent years (Patent Literature 3, Non-Patent Literature 2). It is known that hydrolysis reaction proceeds in a short time without catalyst in high-pressure hot water (Non-Patent Document 3), and reports that xylose and xylooligosaccharides are extracted by hydrolysis of hemicellulose from woody biomass. Yes (Patent Document 2, Non-Patent Document 4). However, there is no example using the high-pressure hot water extraction method as a method for producing collagen and hydroxyapatite.
JP 2000-189065 A JP-A-2005-23041 JP 2002-59118 A Yuki Yamada, “Collagen Peptides Aiming to Expand into Cosmetics and Health Foods”, Jeti, 153, 122-123 (2005) Gamiz-gracia, L., Luque. MD, `` Continuous subcritical water extraction of medicinal plant essential oil: comparison with conventional techniques. '', Talanta, 51, 1179-1185 (2000) Akiya, N., and Phillip, E., Savage, "Roles of Water for Chemical Reactions in High-Temperature Water", Chem. Rev., 102, 2725-2750 (2002) Satoshi Kumagai, Nobuyuki Hayashi, Shuji Fujita, “Production Behavior of Xylose and Xylooligosaccharides from Itagii by Pressurized Hot Water Treatment”, Journal of Japan Society for Food Engineering, 5, 205-210 (2004)

  The present invention has been made to solve such problems of the prior art, and the object of the present invention is to eliminate collagen and hydroxyapatite in a relatively short time without any post-treatment step such as neutralization. It is to provide an apparatus and method that can be obtained. Another object of the present invention is to provide a collagen-containing aqueous extract and hydroxyapatite obtained by these methods.

  The collagen extraction method of the present invention is characterized in that collagen is extracted from fish scales using subcritical water or supercritical water. The method for producing hydroxyapatite of the present invention is characterized in that hydroxyapatite is obtained by extracting collagen from fish scales using subcritical water or supercritical water.

  According to the extraction method and the production method of the present invention using subcritical water or supercritical water, collagen is extracted from fish scales into an aqueous solution, and hydroxyapatite is obtained as a residue after extraction. Although it does not restrict | limit especially as a fish scale which can be used as a raw material in this invention, The scale of a sardine can be used conveniently from availability.

  Here, in the present specification, supercritical water refers to water whose temperature and pressure are at or above the critical point (374 ° C., 22 MPa), and in this specification, subcritical water. Water refers to water having a pressure of 0.2 MPa or more and a temperature lower than 374 ° C. and not lower than 100 ° C., and water in a state compressed to a saturated vapor pressure or higher at that temperature.

  The temperature at the time of fish scale extraction when extracting collagen using subcritical water or supercritical water is preferably in the range of 70 to 400 ° C, more preferably in the range of 100 to 350 ° C, and further in the range of 140 to 250 ° C. The range of is most preferable. Moreover, the pressure at the time of fish scale extraction is preferably in the range of 0.1 to 25 MPa, more preferably in the range of 0.1 to 18 MPa, and most preferably in the range of 0.3 to 6 MPa. If the temperature at the time of extraction is lower than the above, the amount of collagen that remains in the fish scale without being extracted increases.If the temperature at the time of extraction is higher than the above, the molecular weight of the resulting collagen becomes too small, so depending on the purpose of use. Is not preferred. Moreover, when the pressure at the time of extraction is lower than the above, the system may approach the water vapor phase, and when the pressure at the time of extraction is higher than the above, facilities and operating costs increase, which is not preferable in practice. That is, if there is a pressure higher than saturated water vapor, collagen is extracted, and even if the pressure is increased excessively, the extraction rate is not significantly affected.

  Although the time at the time of fish scale extraction changes with the kinds and extraction conditions, the range for 1 to 30 minutes is preferable, and the range for 3 to 10 minutes is more preferable. In addition, if the extraction time is shorter than the above, the amount of collagen that remains in the fish scale without being extracted increases, and if the extraction time is longer than the above, the molecular weight of the resulting collagen becomes too small, It is not preferable depending on the purpose of use.

  The collagen-containing aqueous extract of the present invention can be obtained by the above-described method for producing collagen. Moreover, the hydroxyapatite of the present invention can be obtained by removing collagen from fish scales by the above-described method for producing collagen.

  The collagen extraction apparatus of the present invention is a collagen extraction apparatus for extracting collagen from fish scales using subcritical water or supercritical water, and the subcritical water or supercritical water is obtained by heating and pressurizing the water. A subcritical water / supercritical water supply unit prepared and supplied, and an extraction tube for extracting collagen from fish scales using the subcritical water or supercritical water supplied from the subcritical water / supercritical water supply unit; And a control valve provided on the downstream side of the extraction pipe, wherein the control valve controls the discharge of the extraction liquid while maintaining the pressure in the extraction pipe.

  Further, the hydroxyapatite production apparatus of the present invention is a hydroxyapatite production apparatus that extracts and removes collagen from fish scales using subcritical water or supercritical water, and heats and pressurizes the subcritical water or Collagen is extracted from fish scales using a subcritical water / supercritical water supply unit that prepares and supplies supercritical water and subcritical water or supercritical water supplied from the subcritical water / supercritical water supply unit. And a control valve provided on the downstream side of the extraction pipe. The control valve controls the discharge of the extract while maintaining the pressure in the extraction pipe.

  Thus, in the collagen extraction device and the hydroxyapatite production device, the control valve controls the discharge of the extract discharged from the extraction tube while maintaining the back pressure, so that the state of subcritical water or supercritical water is maintained. The collagen can be extracted while maintaining the above.

  Further, by providing a steel wool filter on the outlet side of the extraction tube, clogging of fish scales can be prevented during collagen extraction, and collagen can be stably extracted over a long period of time.

  According to the collagen extraction apparatus and the extraction method of the present invention, since a process such as adding hydrochloric acid to dissolve hydroxyapatite is unnecessary, a collagen-containing aqueous extract can be obtained in a simpler process and in a shorter time than before. I understand that I can do it.

  Further, according to the hydroxyapatite production apparatus and production method of the present invention, hydroxyapatite remains as a residue after the extraction of collagen, and therefore droxyapatite can be obtained simply by drying it. Therefore, hydroxyapatite can be obtained very simply and in a short time.

  Embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

  FIG. 1 is a conceptual diagram illustrating a collagen extraction apparatus according to an embodiment of the present invention, and this apparatus also serves as a hydroxyapatite production apparatus. As shown in the figure, the apparatus of the present embodiment has a high-pressure pump 2 that feeds water from a water tank 1 and an electric furnace 4 that heats water from the high-pressure pump 2 to prepare subcritical water. ing.

  Moreover, in this embodiment, the extraction pipe | tube 7 which extracts collagen from a fish scale using the subcritical water discharged | emitted from the electric furnace 4 is provided, and the valve | bulb 5a is provided in the inlet side of the extraction pipe | tube 7. FIG. Here, the internal volume of the extraction tube 7 is about 150 mL, the inner diameter is 2.3 cm, and the length is 36 cm. In this embodiment, a bypass 10 is provided in parallel with the extraction pipe 7, and a valve 5 b is provided on the bypass 10. The bypass 10 is provided to bypass the water sent from the electric furnace 4 from entering the extraction pipe 7 until the subcritical water supply is stabilized. A thermometer 6 for measuring the inlet temperature T1 is provided on the inlet side of the extraction pipe 7, and a thermometer 9 for measuring the outlet temperature T2 is provided on the outlet side of the extraction pipe 7.

  A filter 8 made of steel wool is provided near the outlet in the extraction tube 7 in order to prevent the solid content such as fish scale fragments from being discharged. Furthermore, in the apparatus of this embodiment, a nitrogen gas cylinder 15 for supplying pressurized nitrogen gas (less than 11 MPa) is connected to the inlet side of the extraction pipe 7 via a valve 5c. This nitrogen gas cylinder 15 is provided in order to prevent the subcritical water from being vaporized due to a pressure drop when the valve 5a is switched to introduce the subcritical water into the extraction pipe 7 in the initial operation of the apparatus.

  A cooling pipe 11 for cooling the subcritical water after extraction is connected to the lower part of the extraction pipe 7 via a valve 5d. Further, the subcritical water discharged through the bypass 10 is also cooled by the cooling pipe 11. The aqueous extract discharged from the cooling pipe 11 is constantly discharged to the outside through the control valve 13. The control valve 13 functions to maintain the pressure in the extraction pipe 7 and the electric furnace 4 constant (here, 11 MPa) by controlling the opening and closing based on the pressure detected by the pressure sensor 12. . The aqueous extract discharged from the control valve 13 is stored in the storage tank 14.

  FIG. 7 is a conceptual diagram showing a collagen extraction apparatus according to another embodiment of the present invention, and this apparatus also serves as a hydroxyapatite production apparatus. The apparatus of this embodiment is similar to the apparatus of FIG. 1 described above, and includes a high-pressure pump 2 that feeds water from the water tank 1, and an electric furnace 4 that heats water from the high-pressure pump 2 to prepare subcritical water. have. In the present embodiment, a damper 21 for absorbing a rapid pressure change is provided between the high pressure pump 2 and the high pressure pump 2. In this embodiment, a plurality of extraction tubes 7 for extracting collagen from fish scales are provided, and each extraction tube 7 is connected to the electric furnace 4 via a valve 5e. Also in the present embodiment, the bypass 10 and the valve 5b that bypass the water sent from the electric furnace 4 are provided until the subcritical water supply is stabilized. A thermometer 6 for measuring the inlet temperature T1 is provided on the inlet side of the extraction pipe 7, and a thermometer 9 for measuring the outlet temperature T2 is provided on the outlet side of each extraction pipe 7. A filter 8 made of steel wool is provided in the vicinity of the outlet in each extraction tube 7 in order to prevent solids such as fish scale fragments from being discharged. Although not provided in the apparatus of this embodiment, a nitrogen gas cylinder 15 for preventing a pressure drop when introducing subcritical water into each extraction pipe 7 may be connected to each extraction pipe 7. .

  In the apparatus of this embodiment, a water supply pump 22 for discharging the hydroxyapatite remaining in the extraction tube 7 after collagen extraction using water is connected to the valve 5e. Further, a drain for draining hydroxyapatite together with water is connected to the lower part of each extraction pipe 7 through a valve 5f.

  Furthermore, in this embodiment, the cooling pipe | tube 11 which cools the subcritical water after extraction discharged | emitted from each extraction pipe | tube 7 is connected via each valve | bulb 5d. In the cooling pipe 11, subcritical water discharged through the bypass 10 is also cooled. The aqueous extract discharged from the cooling pipe 11 is constantly discharged to the outside through the control valve 13. As in the embodiment of FIG. 1, the control valve 13 controls the opening and closing based on the pressure detected by the pressure sensor 12, thereby keeping the pressure in the extraction pipe 7 and the electric furnace 4 constant (here, 11 MPa).

<Manufacture of collagen and hydroxyapatite>
(Examples 1-4)
Using the apparatus of FIG. 1, the inlet temperature T1 of the extraction tube 7 is set to 147 ° C. (Example 1), 169 ° C. (Example 2), 194 ° C. (Example 3) and 225 ° C. (Example 4). Collagen and hydroxyapatite were produced from fish scales. Using sardine scales that have fallen off naturally at the fish market in Sakaiminato, Tottori Prefecture as a raw material, the sardine scales are soaked in 1M sodium hydroxide solution for 24 hours to remove foreign substances adhering to the surface, and then washed thoroughly with water. And drying. The sardine scales after washing were 50% protein and 50% ash.

  First, 35-40 g of the above sardine scales were charged into the extraction tube 7, high-pressure nitrogen was introduced into the extraction tube 7 through the valve 5 c with the valves 5 a and 5 d closed, and then the valve 5 c was closed. Next, the valve 5b was opened, the high pressure pump 2 and the electric furnace 4 were operated, and supply of water from the water tank 1 was started. The flow rate of the high-pressure pump 2 was adjusted to 100 mL / min, and the pressure of the control valve 13 was adjusted to 11 MPa. Next, after the subcritical water supply became steady, the valves 5 a and 5 d were opened and the valve 5 b was closed to start supplying the subcritical water to the extraction pipe 7.

  FIG. 2 shows the change over time of the outlet temperature T2 of the extraction tube 7 when the inlet temperature T1 of the extraction tube 7 is a constant temperature of 147 ° C., 169 ° C., 194 ° C., and 225 ° C., respectively. As shown in FIG. 2, the initial value of the outlet temperature T2 of the extraction pipe 7 is lower than the inlet temperature T1 of the extraction pipe 7 because the temperature of the raw material and the extraction pipe 7 is lower than the temperature of subcritical water. The outlet temperature T2 increased with the passage time of subcritical water. The extraction time is 8 minutes or 10 minutes, and the collected amount is 800 mL or 1 L. The filter 8 of the extraction tube 7 was not clogged, and stable extraction could be performed.

  After the completion of extraction, the subcritical water was passed through the valve 5b to the bypass 10, and the internal pressure of the extraction pipe 7 was gradually lowered to atmospheric pressure. At that time, the residual liquid in the extraction tube 7 was discharged out of the system without being recovered.

<Extract and residue analysis>
(Extraction rate, residue rate, protein content and ash)
About each Example 1-4, while examining the extraction rate and the residue rate, protein amount and ash content were investigated about each of the extract and the residue, and the result was shown in Table 1. The extraction rate (water-soluble component rate) was calculated from the lyophilized extract and the weight of the charged sample. The residue rate was calculated from the residue dried at 80 ° C. for 24 hours and the weight of the charged raw materials. The reason why the sum of the extract and the residue does not become 100% is that the residue that adheres to the extraction tube 7 and cannot be recovered and the soluble components contained in the residual liquid in the extraction tube 7 are not included. The ash content was determined from the change in weight after treatment in an electric furnace at 600 ° C. for 10 hours. The amount of protein was determined from the measured value of nitrogen by conducting elemental analysis using EA-1108 manufactured by Phisons. As the nitrogen-protein conversion coefficient at this time, 5.62 of cowhide collagen was used.

  As is apparent from Table 1, the extract increased as the inlet temperature T1 increased, while the residue decreased, reaching 48.3% in Example 4. This value is close to 50% ash content of sardine scale, and the protein in the residue at this time is very low at 2.6%, so it was found that most sardine scale collagen was eluted by extraction at 225 ° C for 8 minutes. . Moreover, the ash content in the extract is 1.4 to 5.6% with respect to the extract. When these values are converted into the ash content in the extract, it becomes 13 to 29 mg / 100 mL, which is considered to be apatite in which most of the ash content is slightly dissolved.

(Collagen extraction behavior)
In Examples 1 to 4, as shown in FIG. 2, the hot water temperature in the extraction pipe 7 gradually increases with the water flow time. Furthermore, as shown in Table 1, the extraction temperature has a great influence on the extraction rate, so the extraction amount was considered to change with each extraction time. Therefore, in Example 2 (inlet temperature T1: 169 ° C) and Example 4 (inlet temperature T1: 225 ° C), fractionation was carried out every 200 mL (every 2 minutes), and a total of 5 times (10 minutes) were collected. The extracted amount of each fraction was measured and shown in FIG.

  First, in Example 2, the extraction amount gradually increased from the 0-200 mL fraction of the first collection, and reached the maximum in the 600-800 mL fraction. Since the extraction amount greatly increases in the fraction of 400 to 600 mL, it is considered that the hydrolysis reaction becomes remarkable in this temperature range 143 to 153 ° C. In Example 2, many soluble components are eluted even in the final fraction of 800-1000 mL, and in Table 1, 15.6% of the protein in the residue of Example 2 is further extracted for complete extraction. It takes time.

  On the other hand, in Example 4, it is 156 degreeC or more in the 0-200 mL fraction, and since this value is a temperature range comparable as the 600-800 mL fraction in Example 2, it extracts from the first fraction. Large amount. Since the surface of the scale is very hard, it is considered that the hot water does not reach the inside instantly but gradually undergoes hydrolysis from the surface, and the hot water permeates into the scale accordingly. Therefore, after the collagen in the vicinity of the surface elutes at the initial stage, the extraction amount is considered to decrease despite the increase in hot water temperature.

(Amino acid composition of the extract)
The amino acid composition of the extracts of Examples 1 to 4 was examined, and the results are shown in FIG. Amino acid analysis was carried out by the Waters AccQ • TAG method. That is, the sample was subjected to gas phase decomposition with 6N hydrochloric acid for 21 hours at 110 ° C. and then modified with a fluorescent indicator, and the modified amino acids were separated by reverse phase HPLC. As a detector, a fluorescence spectrophotometer (excitation light wavelength 250 nm, detection wavelength 395 nm) was used. For comparison of amino acid composition, the amino acid composition of enzyme-solubilized collagen (PSC) of sardine scale was also examined. A sample of PSC was obtained by descaling with dilute hydrochloric acid at 10 ° C. or less, solubilizing the obtained crude collagen with pepsin, and purifying it by isoelectric precipitation. FIG. 4 shows the number of amino acid residues per 1000 residues of the PSC and the extracts of Examples 1 to 4.

  Hydroxyproline (Hyp) is an amino acid unique to collagen and is used as an index for measuring the content of collagen in proteins. In addition, since the collagen molecule has a structure in which glycine (Gly) appears every three residues, glycine accounts for about 1/3 of the whole. PSC is considered to be almost 100% collagen because it has undergone a purification process by isoelectric precipitation, and in FIG. 4 glycine is almost 1/3 of the whole, so the extracts of Examples 1 to 4 are of sardine scale collagen. It can be said that it reflects the amino acid composition. In the extracts of Examples 1 to 4 extracted with subcritical water, glycine is close to the value of PSC and almost 1/3 of the whole, and hydroxyproline is similar to PSC. From these facts, it is considered that Examples 1 to 4 do not contain other amounts of other proteins that affect the amino acid composition, and that the thermal decomposition of amino acids with hot water hardly occurs.

(Molecular weight distribution of the extract)
The molecular weight distribution of the extracts of Examples 1 to 4 was examined, and the results are shown in FIG. The molecular weight distribution of the extract was measured by gel permeation chromatography (GPC). The column uses Superdex 200HR10 / 30 (exclusion limit molecular weight (Vo): 1300 kDa) manufactured by Pharmacia, and 0.2N sodium phosphate aqueous solution pH 6.8 is used as the eluent, and ultraviolet absorption at a flow rate of 0.75 ml / min and 210 nm. (UV).

  It is known that when a protein is treated with subcritical water, the molecular weight of the treated protein decreases as the treatment temperature increases. As shown in FIG. 5, the molecular weight distribution of the extract of each example is broad as a whole, and the molecular weight at the peak point of the GPC curve ranges from around 443 kDa in Example 1 to around 6.5 kDa in Example 4. It becomes lower as the extraction temperature becomes higher. As shown in FIG. 2, in any of the embodiments, the temperature difference between the inlet temperature T1 and the outlet temperature T2 is large, so that the temperature difference between the subcritical water and the sample is in contact with the sample. There is also a difference in residence time. Therefore, such a broad molecular weight distribution is considered. For example, if a disc-shaped extraction tube having a large inner diameter and a short length is used, the difference between the hot water temperature and the residence time is reduced, so that gelatin having a narrow molecular weight distribution can be prepared. In any case, it can be understood that gelatin with different molecular weight distribution can be easily prepared by adjusting the temperature of subcritical water.

  Furthermore, the molecular weight distribution of each fraction of Example 2 and Example 4 shown in FIG. 3 was measured, and the results are shown in FIG. In Example 2 (upper side of FIG. 6), the fraction of 0-200 mL shows a peak molecular weight of around 32 kDa even though the outlet temperature T2 is the lowest, and has a lower molecular weight than the other fractions. It is. This fraction has a very low yield as shown in FIG. 3, so the overall effect is small, but other proteins near the extreme surface of the scale and collagen damaged by alkali treatment in the pretreatment are low in temperature. It is thought that it was eluted with. The next fraction, 200-400 mL, was in the highest molecular region, and the molecular weight distribution subsequently shifted to the low molecular region. On the other hand, in Example 4 (lower side of FIG. 6), the outlet temperature T2 of the 0-200 mL fraction is about the same as the 800-1000 mL outlet temperature T2 of Example 2, so both show similar GPC curves. ing. In the subsequent fractions, the molecular weight was small, and in 400-1000 mL, the molecular weight of the peak became a narrow molecular weight distribution of 6.5 kDa or less. In the case of Example 4, if 400-1000 mL is collected, gelatin having a narrow molecular weight distribution can be prepared without a post-treatment step. For gelatin, it is necessary to select a molecular weight distribution suitable for the application. For example, low molecular weight gelatin is advantageous in that it dissolves quickly even in cold water, and high molecular weight gelatin is characterized by high gel strength. In the production method of the present invention, the molecular weight distribution can be easily adjusted by adjusting the extraction temperature and the sampling time. If the temperature of the extraction tube is controlled more precisely, gelatin with a narrow molecular weight distribution can be produced. Is possible.

  According to the present invention, since a collagen-containing aqueous extract can be obtained easily and in a short time, it can be used in the fields of food, medicine, photography, cosmetics and the like.

  Further, according to the present invention, hydroxyapatite can be obtained easily and in a short time, and therefore, it can be used in the field of artificial bones and the like.

It is a conceptual diagram which illustrates the collagen extraction apparatus which concerns on one Embodiment of this invention, and serves also as the manufacturing apparatus of a hydroxyapatite. The time-dependent change of the outlet temperature T2 of an extraction pipe when the inlet temperature T1 of the extraction pipe of FIG. 1 is made constant is shown. It is a figure which shows the extraction amount of each fraction in Example 2 and Example 4 every 200 mL (every 2 minutes). It is a figure which shows the amino acid composition of the extract of each Example 1-4. It is a figure which shows the molecular weight distribution of the extract of each Example 1-4. It is a figure which shows the molecular weight distribution of each fraction of Example 2 and Example 4. FIG. 7 is a conceptual diagram showing an apparatus for extracting collagen according to another embodiment of the present invention, which also serves as an apparatus for producing hydroxyapatite.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water tank 2 High pressure pump 4 Electric furnace 5a Valve 5b Valve 5c Valve 5d Valve 5e Valve 5f Valve 6 Thermometer 7 Extraction pipe 8 Filter 9 Thermometer 10 Bypass 11 Cooling pipe 13 Control valve 12 Pressure sensor 15 Nitrogen gas cylinder 14 Storage tank 21 Damper 22 Water pump

Claims (12)

  A method for extracting collagen, comprising extracting collagen from fish scales using subcritical water or supercritical water.   The method for extracting collagen according to claim 1, wherein the temperature at the time of extraction of the fish scales is in the range of 70 to 400 ° C.   The collagen extraction method according to claim 1 or 2, wherein a pressure at the time of extraction of the fish scales is in a range of 0.1 to 25 MPa.   A method for producing hydroxyapatite, wherein hydroxyapatite is obtained by extracting collagen from fish scales using subcritical water or supercritical water.   The method for producing hydroxyapatite according to claim 4, wherein a temperature at the time of extraction of the fish scales is in a range of 70 to 400 ° C.   The method for producing hydroxyapatite according to claim 4 or 5, wherein a pressure during extraction of the fish scales is in a range of 0.1 to 25 MPa.   A collagen-containing aqueous extract obtained by the production method according to claim 1.   Hydroxyapatite obtained by the production method according to any one of claims 4 to 6. A collagen extraction device for extracting collagen from fish scales using subcritical water or supercritical water,
A subcritical water / supercritical water supply unit for preparing and supplying subcritical water or supercritical water by heating and pressurizing water; and
An extraction tube for extracting collagen from fish scales using subcritical water or supercritical water supplied from the subcritical water / supercritical water supply unit;
A control valve provided on the downstream side of the extraction pipe,
The collagen extraction device, wherein the control valve controls the discharge of the extract while maintaining the pressure in the extraction tube.   The collagen extraction apparatus according to claim 9, wherein a steel wool filter is provided on an outlet side of the extraction tube. A hydroxyapatite production apparatus for extracting and removing collagen from fish scales using subcritical water or supercritical water,
A subcritical water / supercritical water supply unit for preparing and supplying subcritical water or supercritical water by heating and pressurizing water; and
An extraction tube for extracting and removing collagen from fish scales using subcritical water or supercritical water supplied from the subcritical water / supercritical water supply unit;
A control valve provided on the downstream side of the extraction pipe,
The apparatus for producing hydroxyapatite, wherein the control valve controls discharge of the extract while maintaining the pressure in the extraction pipe.   The apparatus for producing hydroxyapatite according to claim 11, wherein a filter made of steel wool is provided on the outlet side of the extraction tube.

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