JP2001352946A - Oyster extracted essence comprising low-molecular fraction at high concentration and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oyster extracted essence usable in various applications without requiring steps of further purification, etc., because the oyster extracted essence comprising a large amount of a low-molecular weight fraction having high physiologically active actions can be obtained in a state with the sufficiently high physiologically active actions and to provide a method for producing the oyster extracted essence by which the oyster extracted essence comprising the large amount of the low-molecular fraction can be obtained and the oyster extracted essence excellent in physical properties such as digestibility or fluidity is obtained by suitably providing steps such as a drying step for minimizing the thermal history such as spray-drying and an alcohol treating step. SOLUTION: This oyster extracted essence comprises >=40 wt.% content of the low-molecular fraction having <=3,000 molecular weight. The method for producing the oyster extracted essence comprises denaturing proteins in a mantle of a raw oyster and then extracting the essence with water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an oyster extract and a method for producing the same.

[0002]

2. Description of the Related Art Oyster extract contains a large amount of free amino acids, minerals, polysaccharides and the like, and is known as a food material having various physiological activities and pharmacological actions. Many products using oyster extract are commercially available, and their use is expanding not only as a seasoning but also as a dietary supplement for nutritional supplementation. However, the conventional method for producing an oyster extract is similar to a general method for producing a seasoning, such as simply extracting an extract component with hot water, and focuses on a component having a physiological action or a pharmacological action. It was not an extraction method.

[0003] In recent years, as a new field in the study of the physiological activity of oysters, a peptide fraction has been shown to have a preventive effect on hypertension, a cholesterol lowering effect, and an effect of suppressing a rapid rise in blood glucose level. There has been a demand for an efficient extraction method.

[0004] Conventional production technology of oyster extract has been positioned as an extension of general production technology of seasonings. Therefore, consideration on digestion and absorption in the gastrointestinal tract, and consideration of safety when the amount of intake is increased and taken for a long time have not been sufficient.

[0005] In the conventional production method, the raw oysters are immersed in hot water for a long period of time to extract the oysters. Substances (mainly waste products, heavy metals, environmental pollutants, etc.) could be extracted into the extract. Furthermore, small spherical virus (SRSV), which is a substance causing food poisoning, and the like may be mixed in the extract from the midgut gland. In addition, due to the long-term extraction work, relatively low bioactive muscle proteins and high-molecular polysaccharides are simultaneously extracted, and the content of the low-molecular fraction containing high bioactive peptides and the like is relatively low, In many cases, further concentration and purification were required.

Further, there are still many points that need to be improved with respect to the aging of the final product and the working characteristics and processing characteristics.

[0007] Conventional oyster extracts are relatively difficult to dry by non-heating such as spray drying or freeze drying due to the high content of high molecular weight polysaccharides (such as glycogen) and free amino acids. Therefore, in drying these, it was necessary to mix excipients (dextrins or other saccharides) at a high concentration due to their hygroscopicity and poor drying properties. Further, when performing such drying, it is desirable to concentrate the extract beforehand. However, in a state where a large amount of a high molecular substance such as a high molecular weight polysaccharide is present, the viscosity cannot be sufficiently concentrated because the viscosity is too high. Takes time.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an oyster extract having a high content of a low molecular fraction containing a large amount of a low molecular substance having excellent physiological activity, and a method for producing the extract. Is to do.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems, and as a result, the raw oyster as a raw material is subjected to a step of denaturing a protein of a mantle before extraction, and Was carried out with water to obtain an oyster extract containing a low-molecular-weight fraction at a high concentration, and succeeded in the present invention. That is, the present invention is as follows. (1) An oyster extract containing at least 40% by weight of a low molecular weight fraction comprising a substance having a molecular weight of 3,000 or less. (2) The weight ratio of the low-molecular fraction to the high-molecular fraction comprising a substance having a molecular weight of 10,000 or more is such that the high-molecular fraction is 1.5 parts by weight or less per 1 part by weight of the low-molecular fraction The oyster extract according to the above (1). (3) The oyster extract according to the above (1) or (2), wherein the water content is 13% by weight or less. (4) The oyster extract according to any one of claims 1 to 3, wherein the lipid content is 1% by weight or less. (5) The oyster extract according to any of the above (1) to (4), which is in the form of a dry powder. (6) The oyster extract according to any one of (1) to (5) above, which is an alcohol-treated product, especially an anhydrous ethanol-treated product. (7) A method for producing an oyster extract, comprising denaturing a protein in a mantle envelope of a raw oyster, and extracting the oyster with water. (8) The method for producing an oyster extract according to the above (7), wherein the denaturation is performed by contacting raw oysters with hot water at 95 ° C to 100 ° C. (9) The method for producing an oyster extract according to the above (8), wherein the contact of the raw oyster with hot water is carried out for 30 seconds to 1 minute. (10) The method for producing an oyster extract according to any one of (7) to (9), wherein the temperature of the water is 5 ° C to 20 ° C. (11) Further, the oyster extract is added with a solid content of 50-6.
(7)-including a step of concentrating to 5% by weight.
(10) The method for producing an oyster extract according to any of (10). (12) The method for producing an oyster extract according to the above (11), further comprising a step of drying by a non-heat drying method. (13) The above (1) further including an alcohol treatment step.
2) The method for producing the oyster extract described in the above. (14) The oyster extract according to any one of (1) to (6), which is obtained by the production method according to any one of (7) to (13).

[0010] The present invention provides an oyster extract containing at least 40% by weight of a low molecular weight fraction comprising a substance having a molecular weight of 3,000 or less. As used herein, the term “substance having a molecular weight of 3,000 or less” refers to a physiologically active substance having a molecular weight of 3,000 or less (such as carnosine or anserine), a free amino acid, and a mineral containing an organic substance. (Organic minerals). Molecular weight 3,0
Substances larger than 00 are not preferred because of poor digestibility in the body and poor processing characteristics. As used herein, the term "bioactivity" means a preventive effect of hypertension, a cholesterol lowering effect, an effect of suppressing a rapid increase in blood sugar level, promotion of fat metabolism, and the like. The oyster extract of the present invention is characterized by containing a low-molecular fraction of 40% by weight or more of the total extract, thereby enhancing digestibility in the body. Further, the processing characteristics are also improved. More preferably, the low-molecular-weight fraction contains at least 50% by weight.
More preferably, the content is 5% by weight or more. For example, an oyster extract containing about 70% by weight of a low-molecular fraction is excellent in the physiological activity derived from the low-molecular fraction and also in the overall balance as an extract, and cannot be obtained by a conventional oyster extract. It has utility as a preparation or processed food.

In a preferred embodiment, the oyster extract of the present invention is such that the weight ratio of the low molecular weight fraction to the high molecular weight fraction comprising a substance having a molecular weight of 10,000 or more is 1 part by weight of the low molecular weight fraction. The polymer fraction is 1.5 parts by weight or less, preferably 1 part by weight or less, more preferably 0.8 part by weight or less. For example, the oyster extract in which the high molecular fraction is suppressed to about 0.4 parts by weight, the relative concentration of the low molecular fraction increases,
Thereby, the physiologically active action of the low molecular fraction can be effectively used. As used herein, “molecular weight of 10,000
The term "zero or more substances" means proteins such as myosin and paramyosin, or polysaccharides such as glycogen. In the present invention, the content of the low molecular weight fraction and the weight ratio to the high molecular weight fraction can be measured by a known method such as gel filtration chromatography. Specifically, it can be measured by fractionating the oyster extract for each molecular weight by gel filtration chromatography, drying, and then precisely weighing.

The oyster extract of the present invention can be suitably produced by the method for producing an oyster extract of the present invention described below. That is, the raw oyster mantle, which is a raw material, is denatured and extracted with water to obtain the oyster extract containing a low-molecular-weight fraction at a high concentration, that is, 40% by weight or more.

The oyster extract of the present invention may be in any form such as liquid, syrup, solid, etc., but is preferably in the form of a dry powder in consideration of the subsequent processing and the like. . This drying is preferably performed by a non-heat drying method described later.

[0014] The present invention also provides an oyster extract having the characteristics of low water content and / or low lipid content in addition to the characteristics of containing the low molecular fraction at a high concentration. The oyster extract is preferably obtained by denaturing the raw oyster mantle used as a raw material, extracting with water, and further treating the dried extract powder with a solvent having a dehydrating and defatting effect such as alcohol. Can be. More specifically, an alcohol-treated product, especially an anhydrous ethanol-treated product, may be mentioned. The alcohol treatment can be specifically performed by an alcohol treatment method described later. The alcohol-treated product has a low water content and a low lipid content, a low bulk density, and excellent fluidity. Due to the low lipid content, oxidation, which is a problem during storage, is suppressed, and the fish odor of oyster extract, which is often a problem with conventional products, is improved. The water content is not more than 13% by weight, preferably not more than 12% by weight, especially not more than 7% by weight, and the lipid content not more than 1% by weight, preferably not more than 0.7% by weight, especially not more than 0.5% by weight. Is preferred. As an alternative to the alcohol treatment, treatment with various organic solvents can be used as long as it has the same effect as that of the present invention and does not adversely affect the living body. An example thereof is hexane treatment.

[0015] The present invention also provides a method for producing an oyster extract, comprising denaturing a protein in a mantle envelope of a raw oyster, and extracting the oyster with water. Examples of a method for denaturing the protein of the mantle include heating and the like. Preferably, the method is performed by contacting raw oysters with hot water at 95 ° C to 100 ° C, preferably for 30 seconds to 1 minute. It is. The temperature of the water used for the water extraction is preferably 5C to 20C. If the temperature is lower than 5 ° C., the extraction efficiency is not sufficient, and if the temperature is higher than 20 ° C., there is a concern that the polymer fraction is mixed. ADVANTAGE OF THE INVENTION According to the manufacturing method of the oyster extract of this invention, the physical damage of the mantle can be minimized by denaturing the protein of the oyster mantle before extraction. This can prevent extraction of excess protein and high molecular polysaccharide. Further, according to the method for producing an oyster extract of the present invention, since high-molecular-weight polysaccharides such as glycogen with high hygroscopicity are not extracted,
No excipients such as dextrin are required.

Thus, the low-molecular-weight fraction contains at least 40% by weight of the low-molecular-weight fraction and the weight ratio of the low-molecular-weight fraction to the high-molecular-weight fraction is 1
An oyster extract having a polymer fraction of 1.5 parts by weight or less based on parts by weight is obtained.

In a preferred embodiment, the production method of the present invention further comprises a step of concentrating the oyster extract to a solid content of 50 to 65% by weight. This concentration is preferably by membrane filtration or vacuum cryogenic concentration. In the present invention, since the oyster mantle is previously denatured as described above, contamination by simultaneous extraction of polymers such as proteins and polysaccharides is minimized, the solid content is concentrated to 50 to 65% by weight. Very little precipitation occurs even if
It is possible to prepare an extract containing a large amount of solids, that is, a high-concentration extract (the absolute amount of the low-molecular fraction is increased).
Further, by performing the concentration step, the subsequent drying step becomes more economical and efficient.

In a preferred embodiment, the production method of the present invention further comprises a step of drying the concentrated extract by a non-heating drying method. By performing the drying under non-heating conditions, substances that are not desirable for food hygiene, such as mutagenic substances (for example, trip P-1) and Maillard reactants (for example, melanoidins) that may be generated during heat treatment, are eliminated. I can do it. The non-heat drying method may include a spray drying method, a freeze drying method and the like. It is preferable to increase the ionic strength before the non-heat drying step.

In a preferred embodiment, the production method of the present invention further comprises an alcohol treatment step. Here, “treatment” means contact with the alcohol,
Usually, it is carried out by immersion. The processing is
Depending on the state of the extract before the treatment, it is usually carried out for about 30 minutes to several hours, preferably for about 2 hours. The alcohol used in the treatment is not particularly limited as long as it does not adversely affect the living body, but anhydrous ethanol is preferred from the viewpoint of safety and the like. As an alternative to the alcohol treatment, treatment with various organic solvents can be used as long as it has the same effect as the present invention and does not adversely affect the living body, and examples thereof include hexane treatment.

The alcohol treatment (and treatment equivalent thereto) removes lipids in the extract powder. Such an effect of removing lipid enhances the digestive absorption of the extract powder, and further improves the flow characteristics of the powder, so that the granulation and tableting of the extract powder are facilitated. By removing the lipid, the lipid content of the resulting oyster extract is reduced to 1% by weight or less, preferably 0.7% by weight or less, particularly 0.5% by weight or less. Lipid content is 1% by weight
Exceeds, oxidation of lipids during storage of the oyster extract,
The problem of causing flavor deterioration becomes remarkable, and the above-described effects are poor.

The alcohol treatment (and treatment equivalent thereto) removes the water content of the extract powder. Due to such an effect of removing water, the flow characteristics of the resulting oyster extract are improved, and the granulation and tableting of the extract powder are facilitated as in the above-described degreasing effect. By removing the water, the water content of the obtained oyster extract becomes 13% by weight or less, preferably 12% by weight or less, particularly 7% by weight or less. If the water content is more than 13% by weight, the powder is agglomerated or dissolved, resulting in poor workability and degreasing effect.

Further, the bulk density of the obtained oyster extract can be reduced by the alcohol treatment (including the treatment equivalent thereto). The bulk density can be reduced by about 20% by weight as compared with the untreated alcohol. More specifically, an oyster extract having a bulk density of about 1.5 to 2 g / cm ³ is obtained. Due to the decrease in the bulk density, handling becomes easy, and granulation and tableting become easy.

According to still another embodiment of the present invention, the particle size of the dried extract powder which has been partially agglomerated after the drying step is artificially adjusted using a crusher or the like,
The flowability of the powder can be further increased.

[0024]

Example 1 200 kg of raw oysters were put in a net, immersed in hot water at 95 ° C. for 1 minute, heat-denatured the mantle, and immediately taken out. 1,000 kg of 15 ° C. cold water was stored in a tank equipped with a stirrer, into which the previously prepared heat-treated oyster was put, and extraction was carried out with gentle stirring at about 20 rpm for 2 hours. Next, insoluble matter such as oysters after extraction were removed, and membrane filtration was performed to obtain an extracted extract (solid content: about 0.3% by weight). The obtained extract is concentrated to a solid content of 4
After increasing the concentration to about 50% by weight, the solid content was further concentrated under reduced pressure to about 50% by weight. Thereafter, the extracted extract was spray-dried (nozzle outlet temperature: 80 ° C., spray tube temperature: 110 ° C.) to obtain a powder (2.55 kg). The solid content was measured using a kett moisture meter.

The extract powder was added to anhydrous ethanol
After adding 0 ml and immersing for 2 hours, filter paper filtration was performed.
This is air-dried and the oyster extract powder of the present invention (2.4)
3 kg). The concentration of the low molecular fraction of the obtained oyster extract powder was 59% by weight, and the weight ratio with the high molecular fraction was about 0.7 part by weight of the high molecular fraction to 1 part by weight of the low molecular fraction. (See Experimental Example 1 below).

Reference Example 1 (Conventional Hot Water Extraction Method) After raw oysters are extracted with hot water at 80 to 90 ° C. for about 1 hour, the extract is filtered, and the filtrate is concentrated to about 30% by weight. Dextrin is added to the concentrate and spray-dried to obtain a powder. The concentration of the low molecular fraction of the obtained oyster extract powder was 35% by weight, and the weight ratio to the high molecular fraction was about 1.9 parts by weight of the high molecular fraction to 1 part by weight of the low molecular fraction. (See Experimental Example 1 below).

EXPERIMENTAL EXAMPLE 1 Ratio of Low Molecular Fraction The oyster extract of the present invention obtained in Example 1 and the conventional oyster extract obtained in Reference Example 1 were subjected to a high molecular fraction (molecular weight of 10,000 or more). And low molecular weight fractions (molecular weight 3
(000 to 3,000) was measured by fractionation by gel filtration chromatography for each molecular weight, followed by drying and precise weighing. Table 1 shows the results.

[0028]

[Table 1]

As shown in Table 1, the low molecular fraction was 35% by weight in the oyster extract of Reference Example 1 (extract powder by the conventional production method), but was 59% by weight in the production method of the present invention. %, An oyster extract containing a low molecular fraction at a high ratio was obtained.

Digestibility Further, the digestibility of the oyster extract powder was verified. 5% for the oyster extract powder of Example 1 and Reference Example 1
An aqueous solution (1.5 ml) was forcibly orally administered into the stomach of a rat by a gastric probe and the plasma free amino acids in the portal vein were added to the plasma sample solution, sulfosalicylic acid was added thereto, and then centrifuged to remove proteins. The supernatant was filtered through a chromato disk, and then the ninhydrin reagent was added to the filtrate, incubated in boiling water, cooled with ice, and quantified over time by colorimetric quantification at 570 nm. The maximum concentration and the time to reach the maximum concentration were calculated. The results are shown in Table 2 below.

[0031]

[Table 2]

Oyster extract powder of the present invention (Example 1)
, The free amino acid in plasma showed the highest value at 8.85 mM 17 minutes after administration, and then decreased sharply. On the other hand, when the oyster extract powder (Reference Example 1) was administered by the conventional production method, the highest value was obtained at 7.98 mM after about 27 minutes. Thus, the digestibility of the oyster extract powder obtained according to the present invention was superior to that obtained by the conventional production method.

Experimental Example 2: Improvement of digestibility by ethanol treatment The oyster extract powder obtained in the same manner as in Example 1 was immersed in absolute ethanol for 2 hours and air-dried (an ethanol-treated product was obtained). On the other hand, the oyster extract powder not subjected to the ethanol treatment was used as a comparative product (ethanol not treated). For each of them, digestive enzymes pepsin for gastric secretion and pancreatin for pancreatic secretion are allowed to act, and a high-molecular fraction (mainly containing proteins) and a low-molecular fraction (mainly containing peptides) are obtained by gel filtration chromatography. The change in the peak was examined.

(Enzyme treatment) 10 mg of extract powder was adjusted to pH
After dissolving in 1 ml of 2.0 buffer, pepsin 0.25
mg was added and the mixture was allowed to act at 37 ° C. for 1 hour. Thereafter, the pH of the reaction solution was adjusted to 7.5, and 0.25 m of pancreatin was adjusted.
g was added and allowed to act for 1 hour. The solution is then
Incubate at 10 ° C for 10 minutes to inactivate the enzyme,
Insoluble matter was removed by centrifugation at 10 m for 10 minutes. The supernatant was subjected to gel chromatography using a TSK-GEL G3000PWXL column (manufactured by Tosoh).

FIG. 1 shows the results. According to FIG. 1, it can be seen that in the oyster extract powder treated with ethanol, the high molecular fraction (molecular weight of about 10,000 to 30,000) is efficiently decomposed by digestive enzymes, and the peak thereof is significantly reduced. .
On the other hand, in the oyster extract powder not treated with ethanol, the decrease in the peak of the high molecular fraction was slight. These results suggest that the oyster extract has a better effect on digestion in the body when subjected to ethanol treatment.

Experimental Example 3: Improvement of digestibility by non-heating drying In the same manner as in Example 1, oyster extract powder was obtained by spray drying (spray-dried product). An oyster extract powder was obtained in the same manner as in Example 1 except that the oyster extract was dried by drum drying (drum temperature: 140 ° C.) (drum dried product). Each was immersed in absolute ethanol for 2 hours and air-dried. Pepsin and pancreatin were allowed to act on each of them in the same manner as in Experimental Example 2, and the changes in the peaks of the high-molecular fraction (mainly containing proteins) and the low-molecular fraction (mainly containing peptides) were determined by gel filtration chromatography. Examined. The results for the dried drum are shown in FIG.

As compared with the case where the spray-dried product of FIG. 1 was treated with a digestive enzyme, the polymer fraction of the drum-dried product of FIG. 2 was not sufficiently digested even with the ethanol treatment.
In the drum drying, protein denaturation occurs due to excessive heating in the drying process compared to spray drying,
It is suggested that the state is less susceptible to enzymatic degradation.

Further, the amount of insoluble matter obtained as a precipitate by centrifugation without digestion during digestion enzyme treatment was measured.
The amount of the insoluble matter was represented by the weight ratio (%) of the infiltrated precipitate excluding the supernatant after centrifugation to the weight of the extract powder before digestive enzyme treatment. Table 3 shows the results.

[0039]

[Table 3]

Drum-dried products contain more insolubles than spray-dried products, suggesting that this may also be a factor inferior in digestibility. Further, in the drum drying, there is a possibility that a mutagenic substance or a Maillard reactant is generated, and in the drying, these harmful substances may precipitate as insoluble substances.

From these results, it was found that the spray-dried ethanol-treated product of the present invention, which did not excessively heat during drying, was particularly excellent in digestibility.

Experimental Example 4: Processing Characteristics (Improvement of Granulation Characteristics by Ethanol Treatment) The oyster extract powder obtained in the same manner as in Example 1 was immersed in absolute ethanol for 2 hours and then air-dried (ethanol treatment). . On the other hand, the oyster extract powder not subjected to the ethanol treatment was used as a comparative product (ethanol not treated). 10-15% water is added to each oyster extract powder and mixed, and the mixture is extruded with a granulator into a 120 mesh wire net at a pressure of 2 kg / cm ² , and the moisture is dried to about 5%. Extruded and granulated. The obtained oyster extract particles are shown in FIG.

In the case of no ethanol treatment, the particle size varied and a large amount of fine powder was mixed. On the other hand, in the case of ethanol treatment, particles having a uniform particle size were obtained. This is considered to be because the flow characteristics were enhanced by the ethanol treatment.

Experimental Example 5: Changes in Physical Properties by Ethanol Treatment The water content, bulk density and lipid content of an anhydrous ethanol-treated oyster extract powder obtained by spray drying obtained in the same manner as in Example 1 were measured. The measurement method and results are shown below.

[Measurement method] Moisture content: Kett moisture meter (moisture scale x 2), sample 2.5 g
Fine weighing. Bulk density: cylindrical glass tube (diameter 1.1 cm x height 2.5
cm), dropped naturally onto the test table 20 times from a height of about 2 cm, and weighed the volume and weight. Lipid amount: After hydrolyzing the sample with hydrochloric acid, the lipid is extracted with ethyl ether and petroleum ether, the ether fraction is concentrated to dryness, and the residue is weighed (acid hydrolysis method).

[Results]

[0047]

[Table 4]

As shown in Table 4, the ethanol-treated product has less water content and lipid than the untreated product. Also,
The bulk density is also lower than the untreated product.

It is considered that the flow characteristics are improved by reducing the water content, the bulk density, and the lipid content. The commercial value of the oyster extract powder significantly decreases due to generation of strong fishy odor due to oxidation, but the oxidation can be suppressed by removing lipids by ethanol treatment.

Experimental Example 6: Suppression of Flavor Deterioration by Ethanol Treatment The effect of suppressing the flavor degradation by spray-drying the anhydrous ethanol treatment was observed.

[Method] The oyster extract powder obtained in the same manner as in Example 1 was immersed in absolute ethanol for 2 hours and then air-dried (ethanol-treated product). On the other hand, the oyster extract powder not subjected to the ethanol treatment was used as a comparative product (ethanol-treated product). Each of the ethanol-untreated product and the treated product was placed in a petri dish, and stored in a 65 ° C. constant temperature room for 5 days and 10 days to be used as samples. The degree of change in flavor of the product stored at 65 ° C. was evaluated using each of the products stored at room temperature (room temperature: 20 ° C.) as a control. The sample was diluted 500 times with distilled water to prepare a test drink. Number of panels: 4 Evaluation of flavor change: -3 considerably weaker -2 slightly weaker -1 slightly weaker 0 almost equivalent +1 slightly stronger +2 slightly stronger +3 fairly strong compared to room temperature storage product

Table 5 shows the results.

[0053]

[Table 5]

The untreated ethanol product had a significantly reduced flavor when stored at 65 ° C. for 10 days as compared with the storage product at room temperature, but no significant difference was observed in the change in flavor of the ethanol-treated product. This is considered to be due to the fact that the lipids were removed by the ethanol treatment, so that the oxidation over time was suppressed, and the deterioration of the flavor was suppressed.

Experimental Example 7: Improvement of flow characteristics by non-heating drying In the same manner as in Example 1, oyster extract powder was obtained by spray drying (spray-dried product). An oyster extract powder was obtained in the same manner as in Example 1 except that the oyster extract was dried by drum drying (drum temperature: 140 ° C.) (drum dried product). An anhydrous ethanol untreated product and an anhydrous ethanol treated product were prepared for the spray-dried product and the drum-dried product, respectively. The particle shape of each prepared sample was observed using an optical microscope. Comparing the particle shapes of the spray-dried product and the drum-dried product, the spray-dried product has a smooth shape with fewer corners, whereas the drum-dried product has
The particle shape was distorted and the flow characteristics were inferior to the spray-dried product. In the spray-dried product, the particles are coagulated and increased by the ethanol treatment, and the flow characteristics are further improved.

[0056]

EFFECTS OF THE INVENTION The oyster extract of the present invention has a high ratio of a low molecular weight fraction having a physiological activity, and therefore can be suitably used for various applications without the necessity of further purification steps. In particular, the oyster extract that has been treated with alcohol is excellent in digestibility and processing characteristics, and has little deterioration in flavor. The oyster extract of the present invention can be easily obtained by the method for producing the oyster extract of the present invention.

[Brief description of the drawings]

FIG. 1 is a graph showing the enzyme degradability of a spray-dried product with and without ethanol treatment.

FIG. 2 is a diagram showing the enzyme degradability of a drum-dried ethanol-treated product.

FIG. 3 is a photograph showing a particle structure obtained by extruding an ethanol-treated product and an ethanol-untreated product (both spray-dried products) by extrusion granulation.

Claims (15)

[Claims] 1. An oyster extract containing at least 40% by weight of a low molecular fraction comprising a substance having a molecular weight of 3,000 or less. 2. The weight ratio of the low molecular weight fraction to the high molecular weight fraction comprising a substance having a molecular weight of 10,000 or more is such that the high molecular weight fraction is not more than 1.5 parts by weight per 1 part by weight of the low molecular weight fraction. The oyster extract according to claim 1. 3. The oyster extract according to claim 1, wherein the water content is 13% by weight or less. 4. The oyster extract according to claim 1, which has a lipid content of 1% by weight or less. 5. The oyster extract according to claim 1, which is in the form of a dry powder. 6. An alcohol-treated product according to claim 1.
An oyster extract according to any one of the above. 7. The oyster extract according to claim 6, wherein the alcohol-treated product is a treated product with anhydrous ethanol. 8. A method for producing an oyster extract, comprising denaturing a protein of a raw oyster mantle, and extracting the oyster with water. 9. The method for producing an oyster extract according to claim 8, wherein the denaturation is carried out by bringing raw oysters into contact with hot water at 95 ° C. to 100 ° C. 10. The method for producing an oyster extract according to claim 9, wherein the contact of the raw oyster with hot water is carried out for 30 seconds to 1 minute. 11. The temperature of the water is 5 ° C. to 20 ° C.
A method for producing the oyster extract according to any one of claims 8 to 10. 12. The method for producing an oyster extract according to claim 8, further comprising a step of concentrating the oyster extract to a solid content of 50 to 65% by weight. 13. The method for producing an oyster extract according to claim 12, further comprising a step of drying by a non-heat drying method. 14. The method further comprising an alcohol treatment step.
A method for producing an oyster extract according to claim 13. 15. The oyster extract according to any one of claims 1 to 7, which is obtained by the production method according to any one of claims 8 to 14.