JP2011109927A - Method for extracting fish-originated collagen peptide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for extracting fish-originated collagen peptide, by which the collagen peptide can efficiently be recovered in a high recovery rate, while shortening the treating time. <P>SOLUTION: The method for extracting the fish-originated collagen peptide is characterized by including a crushing process for finely crushing a fish-originated raw material so that a decrease rate in the diffraction intensity of the Miller index (002) of hydroxyapatite crystal obtained by X-ray diffraction method on the basis of the un-crushed fish-originated raw material is fit to a prescribed range; and a process for performing a treatment for extracting collagen protein from the finely crushed fish-originated raw material in 30 to 70°C water and a treatment for hydrolyzing the extracted collagen protein into collagen peptide with a protease, as one process; wherein the lower limit value of the prescribed range is determined from a viewpoint that the recovery of the collagen peptide is ≥75%; and the upper limit value of the prescribed range is determined from a viewpoint that the increase in the ratio of the recover rate of the collagen peptide to the decrease rate of the diffraction intensity is maintained at ≥0.34. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for extracting a collagen peptide derived from fish.

Collagen is used in a wide range of fields, from food to pharmaceuticals and cosmetics, and is said to have an annual market of 30 billion yen. Conventionally, this collagen has been mainly derived from mammals such as cattle and pigs, but its use has been avoided since the occurrence of bovine spongiform encephalopathy and foot-and-mouth disease. In particular, collagen used in cosmetics is mostly from aquatic animals.
Collagen and gelatin, which is a modified product thereof, are subjected to a low molecular weight (hydrolysis) treatment with an enzyme or the like for the purpose of improving absorption into the body or skin and imparting functionality. In addition, the sample which received this process is called collagen peptide.

  As a method for extracting a collagen peptide from an aquatic animal, a method is known in which collagen peptide is extracted by pulverizing undecalcified fish scales to promote collagen solubilization and contact with an enzyme (for example, patents). Reference 1).

JP 2004-57196 A

  However, in order to perform collagen extraction by the extraction method, collagen having a hard triple helix structure, particularly internal collagen fibers, is solubilized. The above heat treatment is required to be gelatinized. For this reason, the collagen extraction treatment and the subsequent hydrolysis treatment with an enzyme must be performed as separate steps, and a cooling step is also required between the two steps. The heat treatment can be omitted, but when it is omitted, the recovery rate of the collagen peptide is remarkably reduced. Further, the pulverization treatment in the extraction method has the disadvantage that a high concentration of collagen peptide cannot be obtained at one time because the bulk of fish scales increases, and further improvement is desired.

  Accordingly, an object of the present invention is to provide a method for extracting a fish-derived collagen peptide that can efficiently recover a collagen peptide at a high recovery rate while eliminating the inconvenience and shortening the processing time.

  In order to achieve such an object, the method for extracting a fish-derived collagen peptide of the present invention uses a fish-derived raw material as a diffraction pattern before the milling of the Miller index (002) of a hydroxyapatite crystal obtained by an X-ray diffraction method. Raw material pulverization step for finely pulverizing the strength reduction rate to fall within a predetermined range, treatment for extracting collagen protein from the pulverized fish-derived raw material in water at a temperature of 30 ° C to 70 ° C, and extracted collagen A collagen peptide extraction step in which the process of hydrolyzing the protein into a collagen peptide by a proteolytic enzyme is performed as one step, and the lower limit value of the predetermined range is determined from the viewpoint of making the recovery rate of the collagen peptide 75% or more The upper limit of the predetermined range is the recovery rate of the collagen peptide with respect to the rate of decrease of the diffraction intensity. Characterized in that it is determined from the viewpoint of maintaining the increase rate to 0.34 or more.

  The inventor has found that the extraction rate of collagen can be improved by carrying out a pulverization process so that a sufficient mechanochemical effect is given to the fish-derived raw material. Here, the “mechanochemical effect” means that mechanical energy (impact or friction) is applied to a sample that has been microparticulated during the pulverization process, so that a part of the mechanical energy is accumulated in the particle and distortion of the crystal structure or chemical This is an effect of causing a bond breakage.

  The inventor also shows that the degree of mechanochemical effect is proportional to the degree of decrease in diffraction intensity belonging to the c-axis of hydroxyapatite crystals contained in fish-derived raw materials that can be measured by X-ray diffraction. I found out.

  Specifically, the inventor has excellent mechanical strength because the fish-derived material is composed of hydroxyapatite, which is an ionic crystal belonging to the hexagonal system, and collagen fibers aligned along the c-axis of the crystal. However, as the mechanochemical effect imparted to the raw material increases, the diffraction intensity obtained by the X-ray diffractometry in the Miller index (002) belonging to the c-axis of the crystal becomes higher before pulverization. It was found that the intensity was lower than the diffraction intensity.

  Based on this knowledge, the raw material can be finely pulverized so that the diffraction intensity at the Miller index (002) belonging to the c-axis is reduced by a predetermined ratio or more compared to the diffraction intensity before pulverization.

  The lower limit value of the predetermined ratio is set to exceed 75% because the collagen peptide recovery rate is originally required to be 75% or more as an industrial requirement.

  On the other hand, it is sufficient to perform a process of finely pulverizing the collagen peptide recovery rate to reach almost 100% (95% to 98%), and additional processing steps are added to increase the recovery rate. On the contrary, the continuous execution results in waste in terms of industrial work efficiency. Accordingly, the upper limit value of the predetermined range can maintain the increase in the ratio of the recovery rate of the collagen peptide to the decrease rate of the diffraction intensity at 0.34 or more so that the recovery rate of the collagen peptide does not exceed 95%. Set to.

  According to the inventors' experiment, in the method for extracting a fish-derived collagen peptide of the present invention, the predetermined ratio is preferably set to 13.4% to 37.2%.

  In addition, the recovery rate of this collagen peptide means the relative ratio of the mass of the collect | recovered collagen peptides when the collagen peptide contained in a raw material is set to 100.

  And after performing the said fine grinding process, the process which extracts a collagen protein and the process which hydrolyzes the extracted collagen protein to a collagen peptide by a proteolytic enzyme are performed.

  The fish-derived raw material that has been given a sufficient mechanochemical effect by executing the fine pulverization treatment should be subjected to collagen solubilization and extraction in water at a temperature of 30 ° C. to 70 ° C. in which enzyme activity is maintained. Can do. Therefore, the process of extracting the collagen protein and the hydrolysis process, which have been conventionally performed in separate processes, can be performed at the same time, and the cooling process is omitted between the extraction process and the hydrolysis process. Can do.

  In addition, according to this pulverization treatment, the bulk is remarkably low as compared with the conventional case, so that in the process of extracting the collagen protein and the hydrolysis treatment, the collagen peptide is extracted once more for the pulverized raw material. Can do.

  As a result, according to the method for extracting a fish-derived collagen peptide of the present invention, the collagen peptide can be efficiently recovered at a high recovery rate while shortening the processing time.

  The collagen peptide recovery rate is defined as the maximum recovery rate of collagen peptide that can be recovered from fish scales per unit mass as 100% recovery rate. This maximum value is determined by experiment. For example, even when the duration of pulverizing fish scales with a convergence mill is extended, the value when the recovery rate is not improved is determined as the maximum value.

The figure which shows the diffraction pattern obtained by the X-ray-diffraction measurement of Examples 3-5 and the comparative example 2 which use the scale of a sword fish as a sample. Explanatory drawing of the relationship between the reduction rate of the diffraction intensity of the Miller index (002) obtained by the X-ray-diffraction measurement of Examples 1 and 2 and Comparative Example 1 which use a cocoon scale as a sample, and the extraction rate of a collagen peptide. Explanatory drawing of the relationship between the reduction rate of the diffraction intensity of the Miller index | exponent (002) obtained by the X-ray-diffraction measurement of Examples 3-5 and the comparative example 2 which uses a sword fish scale as a sample, and the extraction rate of a collagen peptide.

  Next, embodiments of the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is a graph showing the diffraction intensity belonging to the c-axis of a hydroxyapatite crystal contained in a raw material derived from sword fish, measured by X-ray diffraction. Fig.1 (a) is a graph of the diffraction intensity at the time of performing only the primary grinding | pulverization by a cutter mill as a grinding | pulverization process. FIG. 1 (b) is a graph of diffraction intensity when a fine grinding process of 20 minutes is performed by a convergence mill described later in addition to the primary grinding. FIG.1 (c) is a graph of the diffraction intensity at the time of performing the fine grinding process for 40 minutes similarly. FIG. 1 (d) is a graph of the diffraction intensity when the fine grinding process for 60 minutes is similarly executed.

  As apparent from FIGS. 1 (a) to 1 (c), the longer the execution time of the fine pulverization process by the convergence mill and the higher the mechanochemical effect given to the raw material, the higher the mirror belonging to the c-axis of the crystal. It can be seen that the diffraction intensity at the index (002) is lower than the diffraction intensity before grinding.

  Further, as is clear from FIGS. 1C and 1D, when the reduction rate of the diffraction intensity reaches a predetermined level, the diffraction intensity can be increased even if the pulverization process is continued for a longer time. It can be seen that there is almost no change in the decrease rate.

  In this embodiment, based on the results of these experiments, the raw material is finely pulverized so that the reduction rate based on the diffraction intensity before pulverization in the Miller index (002) belonging to the c-axis is within a predetermined range. The process which performs is performed.

  The type of fish-derived raw material used in the method for extracting a fish-derived collagen peptide in the present embodiment is not particularly limited, and examples thereof include fish such as flat eyes, sea bream, sea bream, sea bream, sword fish, and sea bream. The found tendency is similarly shown in any fish. Moreover, if it is a raw material derived from a fish, a fish skin may be sufficient, but since a fish scale has comparatively little fish odor, it is preferable.

  In the finely pulverizing process of the fish-derived raw material of the present embodiment, the raw material derived from the undecalcified fish that has been previously cleaned to remove impurities is first ground for about 90 seconds with a cutter mill, and then, X-ray The hydroxyapatite crystal obtained by the diffraction method is finely pulverized so that the diffraction intensity at the Miller index (002) is reduced by 13.4% to 37.2% compared to the diffraction intensity before pulverization.

  The fine pulverization means is not particularly limited, but a high-speed powder reactor that finely pulverizes the powder by rotation of a processing container containing a plurality of pulverization medium balls and powder is preferably used. It is preferable to use a high-speed powder reactor utilizing the principle of a convergence mill disclosed in US Pat. No. 3,486,682 or Japanese Patent No. 3533526.

  This high-speed powder reactor is preferable as the fine pulverization means of the present embodiment because it can reduce the amount of wear due to collision of the pulverization container and pulverization balls and can be easily scaled up. However, since the execution time of the pulverization process required to achieve the predetermined reduction rate of diffraction intensity (13.4% to 37.2%) differs depending on the scale and performance of the high-speed powder reactor, an experiment was conducted in advance. Thus, it is preferable to obtain the relationship between the operating time of the apparatus and the reduction rate.

  In the collagen peptide extraction process of the present embodiment, the process of extracting collagen protein from the finely pulverized fish-derived raw material and the process of hydrolyzing the extracted collagen protein into collagen peptides by proteolytic enzymes are performed as one process. .

  First, as a process for extracting the collagen protein, the finely pulverized fish-derived raw material is immersed in water. Thereby, most of the collagen protein as a raw material derived from fish is gelatinized and eluted in water, so that it can be hydrolyzed by a proteolytic enzyme described later. In order to gelatinize this collagen protein in a short time and elute it in water, the water temperature is preferably 30 ° C. or higher. On the other hand, since the enzyme which hydrolyzes the below-mentioned protein will lose activity when the said water temperature exceeds 70 degreeC, it is preferable that it is 60 degrees C or less.

  Next, the treatment for hydrolyzing the collagen protein is performed by hydrolyzing the collagen protein eluted in the water with a proteolytic enzyme. Since the present hydrolysis treatment can act not only on collagen (gelatin) solubilized in water but also on collagen that cannot be solubilized under the above temperature conditions, the recovery rate of collagen peptides can be further increased.

  The proteolytic enzyme used in the present embodiment is not particularly limited as long as it can hydrolyze collagen protein without chemical decalcification treatment. For example, “Protease N Amano G (trademark)” manufactured by Amano Enzyme Co., Ltd., “Proleather FG-F (trademark)” and “Denapsin 2P (trademark)” manufactured by Nagase ChemteX Corporation are preferable. . In addition, denaturation of these enzymes and loss of activity can be carried out by heat treatment for 10 minutes in a boiling water bath (95 ° C.).

  The collagen peptide obtained by the method for extracting fish-derived collagen peptide of this embodiment can be further concentrated and purified by known means. For example, the concentration includes centrifugal concentration and lyophilization, and the purification includes activated carbon and synthetic adsorption resin. In the case of purification using activated carbon, it is preferable to use it together with an auxiliary agent (for example, diatomite).

  According to the method for extracting a fish-derived collagen peptide of this embodiment, the diffraction intensity at the Miller index (002) of a hydroxyapatite crystal contained in a fish-derived raw material is measured by an X-ray diffraction method, and the diffraction intensity before pulverization By grasping the reduction rate of the diffraction intensity with reference to the above, the degree of occurrence of the mechanochemical effect can be recognized. Since the recovery rate of the collagen peptide varies depending on the degree of occurrence of the mechanochemical effect, the minimum necessary amount is required to generate a mechanochemical effect that can achieve the recovery rate of the collagen peptide in an industrially efficient manner. The degree to which the pulverization process should be performed can be recognized.

  In addition, fish-derived raw materials that have been finely pulverized so as to give a mechanochemical effect can realize solubilization and high extraction of collagen in a temperature range where the enzyme does not lose activity at 30 ° C to 60 ° C. Collagen protein extraction treatment by heating and enzymatic hydrolysis treatment, which have been performed in separate steps, can be performed simultaneously.

  In addition, according to this fine pulverization process, the volume generated is significantly smaller than the volume generated by the conventional pulverization process. Collagen can be extracted from the target.

  As a result, according to the method for extracting a fish-derived collagen peptide of the present embodiment, the collagen peptide can be efficiently recovered at a high recovery rate while shortening the processing time.

[Experimental example using rice cake]
<Example 1>
(Scale collection, washing, degreasing, drying)
In order to prevent a decrease in freshness, the scales of the salmon frozen and stored at -35 degrees were sufficiently washed with tap water. Acetone was added to the washed scales for degreasing, and this was repeated several times. Further, the scales of the straw were naturally dried in a fume hood and then dried in a desiccator containing silica gel for 2 to 3 days to obtain washed dry scales.

(Primary crush of scales)
The washed dry scales were pulverized for 90 seconds at a rotational speed of 30000 rpm with a power grinder (Cutter Mill, manufactured by Master) at a room temperature of 20 to 25 ° C.

(Secondary crushing of scales)
The coarsely pulverized scales were finely pulverized using a high-speed powder reactor (manufactured by Makabe Giken Co., Ltd.) using the principle of a convergence mill described in Japanese Patent No. 3486682 and Japanese Patent No. 3533526. Specifically, 30 g of coarsely pulverized scales as raw material powder and 271 g (80 ml) of zirconia balls having a diameter of 10 mm as medium balls are put into a zirconia pulverization vessel (1000 ml) of the above high-speed powder reactor, The pulverization process was performed for 60 minutes at a rotation speed of 700 rpm.

  Thereby, the average particle size of the finely pulverized scales obtained was 36 μm. Further, the diffraction intensity attributed to the Miller index (002) of the hydroxyapatite crystal by X-ray diffraction method was reduced by 35.8% compared with the diffraction intensity before pulverization.

(Extraction / hydrolysis)
0.1 g of the above finely pulverized scale was weighed, and 0.1 ml of protease (Amino Enzyme Co., Ltd. Pro Leather (trademark) FG-F) was added to 10 ml of distilled water and 14 mg / ml. The concentration was about 140 μg / ml, and the liquid was kept at 60 ° C. and stirred and mixed for 60 minutes for hydrolysis.

(Solid-liquid separation)
The suspension after hydrolysis was centrifuged at 12000 × g for 20 minutes, and a supernatant containing collagen peptide was collected.

(Enzyme denaturation)
The enzyme was inactivated / denatured by heating for 10 minutes in a boiling water bath.

(Removal of denaturing enzyme)
Centrifugation was performed under the same conditions as in solid-liquid separation, the denatured enzyme was removed, and a supernatant (collagen peptide) was obtained.

  The collagen peptide concentration of the above solution was determined by quantification by the Lowry method using bovine serum albumin as a standard protein (non-patent document: Lowry et al. (1951) J. Biol. Chem. 192, p263-275). The amount of collagen peptide was calculated by multiplying the obtained concentration by the amount of the solution after the enzyme denaturation treatment. If the enzyme is subjected to a denaturation treatment before the solid-liquid separation operation, hydroxyapatite and the denatured enzyme can be removed simultaneously during the solid-liquid separation. In this embodiment, collagen obtained by the extraction / hydrolysis step is used. In order to purely evaluate the amount of peptide, the treatment was performed according to the above procedure.

(Measurement of X-ray diffraction intensity)
The fish scale powder sample used for the measurement of the X-ray diffraction intensity was sufficiently deproteinized to avoid this because the baseline of the diffraction intensity was greatly disturbed when the protein coexists. Specifically, the fish scale powder sample was subjected to the same operation as in Example 1 of JP-A-2004-57196, and the resulting residue (hydroxyapatite) was washed and dried to obtain a measurement sample. JDX-3530 manufactured by JEOL Ltd. was used for the measurement of X-ray diffraction intensity. X-ray source: Cu / Kα ray, tube voltage: 30 kV, tube current: 30 mA, measurement range: 2θ = 70 °, X-ray The scan speed was measured under the condition of 0.04 ° × 0.5 sec.

(Collagen peptide recovery rate)
The results of the reduction rate of the diffraction intensity from the diffraction intensity before grinding and the recovery rate of the collagen peptide in the Miller index (002) of the hydroxyapatite crystal are shown in the column of Example 1 of Table 1 shown in FIG. 2 (a). Indicated. The recovery rate of collagen peptide in Example 1 was 97.8%.

  The collagen peptide recovery rate is defined as the maximum recovery rate of collagen peptide that can be recovered from fish scales per unit mass as 100% recovery rate. This maximum value is determined by experiment. For example, even when the duration of pulverizing fish scales with a convergence mill is extended, the value when the recovery rate is not improved is determined as the maximum value. In the state where the recovery rate of the collagen peptide was not improved, the reduction rate of the diffraction intensity of the Miller index (002) was not improved to 40% or more. From this, the reduction rate of the diffraction intensity has an upper limit of 40%, and if the reduction rate reaches 40%, it is estimated that the recovery rate of the collagen peptide becomes 100%.

<Example 2>
The same operation as in Example 1 was performed except that the secondary pulverization time was changed to 180 minutes.

  The results of the reduction rate of the diffraction intensity from the diffraction intensity before grinding and the recovery rate of the collagen peptide in the Miller index (002) of the hydroxyapatite crystal are shown in the column of Example 2 of Table 1 shown in FIG. Indicated. In addition, the recovery rate of the collagen peptide in Example 2 was 99.8%.

<Comparative Example 1>
The same operation as in Example 1 was performed except that secondary pulverization was not performed.

  The results of the reduction rate of the diffraction intensity from the diffraction intensity before pulverization and the recovery rate of collagen peptide in the Miller index (002) of the hydroxyapatite crystal are shown in Comparative Example 1 column of Table 1 shown in FIG. It was. The recovery rate of collagen peptide in Comparative Example 1 was 60.3%.

<Discussion>
FIG. 2B shows the relationship between the reduction rate of the diffraction intensity and the recovery rate of the collagen peptide in the Miller index (002) of the hydroxyapatite crystals of Examples 1 and 2 and Comparative Example 1 using salmon fish scales as samples. . Note that the reduction rate of the diffraction intensity was obtained by calculating the reduction rate of the diffraction intensity of each experimental example based on the diffraction intensity of Comparative Example 1.

  According to FIG. 2 (b), the approximate expression (1) is calculated as an approximate curve between the reduction rate of the diffraction intensity and the recovery rate of the collagen peptide obtained from experiments using straw as a raw material.

  As described above, the recovery rate of collagen peptides is originally required as 75% or more as an industrial requirement. Therefore, when calculating based on the approximate expression (1), it can be seen that the recovery rate of collagen peptide exceeds 75% when the decrease rate of the diffraction intensity is 3.82% or more.

  In addition, it is sufficient to perform a pulverization process so that the recovery rate of the collagen peptide reaches almost 100% (95% to 98%), and a processing step is added to increase the recovery rate. Continued execution is not preferable from the viewpoint of industrial work efficiency.

  Therefore, when calculated based on the formula (1), if the reduction rate of the diffraction intensity is 13.7% or less, the recovery rate of the collagen peptide can be adjusted to within 95%, from the viewpoint of industrial work efficiency. It can be seen that undesired extra pulverization can be avoided. It should be noted that the rate of increase in the recovery rate of the collagen peptide when the decrease rate of the diffraction intensity is 13.7%, that is, the approximate expression (1) when the decrease rate of the diffraction intensity is 13.7% It can be seen that the inclination of the tangent line is 0.81.

[Experimental example using sword fish]
<Example 3>
The sample was changed from salmon scales to sword fish scales. Moreover, it pulverized for 20 minutes using a convergence mill as secondary pulverization. Other operations were performed in the same manner as in Example 1.

  The results of the reduction rate of the diffraction intensity from the diffraction intensity before grinding in the Miller index (002) of the hydroxyapatite crystal and the recovery rate of the collagen peptide are shown in the column of Example 3 of Table 2 shown in FIG. Indicated. The recovery rate of collagen peptide in Example 3 was 80.3%.

<Example 4>
The same operation as in Example 3 was performed except that the time for secondary pulverization was 40 minutes.

  The results of the reduction rate of the diffraction intensity from the diffraction intensity before grinding in the Miller index (002) of the hydroxyapatite crystal and the recovery rate of the collagen peptide are shown in the column of Example 4 of Table 2 shown in FIG. Indicated. In addition, the recovery rate of the collagen peptide in Example 4 was 92.9%.

<Example 5>
The same operation as in Example 6 was performed except that the time for secondary pulverization was 60 minutes.

  The results of the reduction rate of the diffraction intensity from the diffraction intensity before grinding in the Miller index (002) of the hydroxyapatite crystal and the recovery rate of the collagen peptide are shown in the column of Example 5 of Table 2 shown in FIG. Indicated. In addition, the recovery rate of the collagen peptide in Example 5 was 99.9%.

<Comparative Example 2>
The same operation as in Example 3 was performed except that secondary pulverization was not performed.

  The results of the reduction rate of the diffraction intensity from the diffraction intensity before grinding and the recovery rate of the collagen peptide in the Miller index (002) of the hydroxyapatite crystal are shown in Comparative Example 2 column of Table 2 shown in FIG. 3 (a). It was. The recovery rate of collagen peptide in Comparative Example 2 was 37.9%.

<Discussion>
FIG. 3 (b) shows the relationship between the reduction rate of the diffraction intensity and the recovery rate of the collagen peptide in the Miller index (002) of the hydroxyapatite crystals of Examples 3 to 5 and Comparative Example 2 using the fish scales of sword fish as a sample. . The reduction rate of the diffraction intensity was obtained by calculating the rate of decrease in the diffraction intensity of each experimental example on the basis of the diffraction intensity of Comparative Example 2.

  According to FIG. 3 (b), the approximate expression (2) is calculated as an approximate curve between the reduction rate of the diffraction intensity and the recovery rate of the collagen peptide obtained from an experiment using Akito fish.

  Similarly, when calculated based on the approximate expression (2), it can be seen that when the reduction rate of the diffraction intensity is 13.4% or more, the recovery rate of the collagen peptide exceeds 75%.

  Moreover, if it calculates based on the said Formula (2), if the decreasing rate of the said diffraction intensity is 37.2% or less, it turns out that the collection | recovery rate of a collagen peptide can be adjusted within 95%. It should be noted that the rate of increase in the collagen peptide recovery rate when the reduction rate of the diffraction intensity is 37.2%, that is, the approximate expression (2) when the reduction rate of the diffraction intensity is 37.2%. It can be seen that the slope of the tangent line of) is 0.34.

<Result>
According to FIG. 2 (b) and FIG. 3 (b), when secondary pulverization is performed by a pulverizer capable of imparting a mechanochemical effect to the fish scales after primary pulverization, both the fish scales of salmon and sword fish are hydroxyapatite over time. It can be seen that the decreasing rate of the diffraction intensity in the Miller index (002) of the crystal increases.

  Further, according to FIGS. 2B and 3B, when the reduction rate of the diffraction intensity reaches a predetermined level, the diffraction intensity decreases even if the pulverization process is continued for a longer time. It can be seen that the rate hardly changes.

  As a result, the reduction rate of the diffraction intensity is so small that it falls within a predetermined range (e.g., 3.82% to 13.7% in the case of a salmon, 13.4% to 37.2% in the case of an autumn sword fish). It has been clarified that according to the method for extracting a collagen peptide derived from fish that performs pulverization, the collagen peptide can be efficiently recovered at a high recovery rate while shortening the processing time.

Claims (2)

A raw material pulverizing step for finely pulverizing a fish-derived raw material so that the reduction rate of the Miller index (002) of the hydroxyapatite crystal obtained in the X-ray diffraction method is within a predetermined range with respect to that before pulverization; Collagen that performs a process of extracting collagen protein from the finely pulverized fish-derived raw material and a process of hydrolyzing the extracted collagen protein into a collagen peptide by a proteolytic enzyme in water at a temperature of from 0C to 70C. Having a peptide extraction step;
The lower limit value of the predetermined range is determined from the viewpoint of making the recovery rate of collagen peptide 75% or more, and the upper limit value of the predetermined range is an increase in the ratio of the recovery rate of collagen peptide to the decrease rate of the diffraction intensity. A method for extracting a collagen peptide derived from fish, characterized in that it is determined from the viewpoint of maintaining a value of 34 or more. 2. The method for extracting a fish-derived collagen peptide according to claim 1, wherein the predetermined ratio is 13.4% to 37.2%.