JP2557015B2 - Method for producing fish and shellfish extract - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fish and shellfish extract from the internal organs of fish and shellfish or an extract thereof.
More specifically, it relates to a method for producing a fish and shellfish extract from which heavy metal components have been removed.

[0002]

2. Description of the Related Art During the processing of fish and shellfish, a large amount of processing by-products such as the internal organs and the boiling water used and discharged in each process are generated. For example, in the processing of scallops and squid,
It is estimated that tens of thousands of tonnes of viscera are discarded each year.

Of these, for processing water such as steamed water, a method is proposed in which solid-liquid separation is carried out by centrifugation or filtration, and the permeate containing the extract is used as it is or as a raw material for natural seasonings. Has been done. On the other hand, most of the internal organs are used as salt and salt, but most of them are buried and incinerated as industrial waste at the expense of the fishery processor.

However, the visceral portion also contains a large amount of taste components such as various amino acids and nucleic acid-related substances (for example, inosinic acid) and useful substances such as eicosapentaenoic acid (EPA) and carotenoids, which is excellent. It can be expected to be used as a raw material for natural seasonings by utilizing its taste, and also as a raw material for fertilizer and feed because it has a fattening effect on agricultural crops and livestock. Therefore, it is desirable to effectively use the internal organs of fish and shellfish for effective use of resources and promotion of the fishery processing industry through reduction of processing costs.

However, the internal organs of fish and shellfish have a problem that heavy metals in the environment are easily concentrated according to the food chain. However, for foods such as natural seasonings,
In addition, fertilizers and feeds are raw materials containing a small amount of heavy metals to the extent that there is no risk of physiological effects on the human body, as only those ingredients that are ingested by the human body through agricultural products and livestock are highly demanded. However, there is a concern that the image of the product may be damaged. Therefore, in order to effectively use the internal organs of fish and shellfish, how to effectively remove heavy metals contained in the internal organs, particularly cadmium (Cd), at low cost is a problem.

Removal of heavy metals can be carried out by various methods for industrial wastewater, for example, adsorption separation method using ion exchange resin,
Many extraction methods using chelating agents and organic solvents have been proposed. However, even if these methods are applied to the extract from the internal organs of fish and shellfish, the recovery of umami components such as various amino acids and inosinic acid is insufficient. In addition, there are problems in safety and cost when used as raw materials for fertilizers, feeds and natural seasonings.

On the other hand, regarding the separation of impurities during the processing of fish and shellfish, a proteolytic enzyme may be added prior to solid-liquid separation to increase the yield (Japanese Patent Laid-Open No. 1-187065), an ultrafiltration membrane or a reverse osmosis membrane. To remove high-molecular peptides, collagen, or excess salt by adding a process using the method described in JP-A-60-27359.
Japanese Patent Laid-Open No. 1-128763). However, there is no specific description in these prior art documents regarding the removal of heavy metals dissolved in the system.

[0008]

DISCLOSURE OF THE INVENTION The present invention effectively utilizes the internal organs of fish and shellfish that have been conventionally disposed of. Therefore, trace amounts of heavy metals contained in the internal organs of fish and shellfish are removed by an economical method, and fertilizer An object is to provide a method for producing an extract-containing product by extracting an extract that is useful as a raw material for feed or natural seasonings.

[0009]

[Means for Solving the Problem] As a result of various studies on the method for removing heavy metals in the internal organs of fish and shellfish, the present inventors found that most of the heavy metals contained in the internal organs of fish and shellfish are bound to water-soluble proteins. Focusing on this fact, they have found that the removal of the visceral extract can be effectively achieved by performing ultrafiltration in a specific pH range, and the present invention has been completed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the present invention is: (1) A method for producing a fish and shellfish extract, characterized in that the visceral extract of fish and shellfish is adjusted to pH 3.5 to 9 to carry out ultrafiltration to remove heavy metal components. , (2) The above method characterized by performing heat treatment and solid-liquid separation prior to ultrafiltration, (3) The above-mentioned method characterized in that the extract is treated with a proteolytic enzyme prior to solid-liquid separation. Each method, (4) each of the above methods in which the fish and shellfish viscera are scallop midgut glands, and (5) each of the above methods in which the fish and shellfish viscera is squid liver are provided.

In the present invention, there is no limitation on the kind of raw material fish and shellfish which makes effective use of the internal organs, but fish and shellfish which have a high content of active ingredients such as nucleic acids and amino acids and a large accumulation of heavy metal components are preferred. Be the target. Specific examples include scallop midgut gland and squid liver. The extract of the internal organs may be a by-product of the fish / shellfish product manufacturing process, or may be an extract prepared by treating the internal organs after taking them out. In the latter case, the internal organs of seafood, such as seafood, is crushed as it is, or crushed by adding water up to 10 times by weight, preferably up to 5 times by weight.
Instead of water, salt water or a buffer solution having a pH range described below may be used.

The obtained liquid is subjected to solid-liquid separation if necessary. For example, when a hard foreign substance such as a shell or a bone that may damage the membrane in the ultrafiltration described later is contained, this step is essential. Solid-liquid separation can be performed using various known methods such as centrifugation and filtration with a filter cloth.

The obtained extract is ultrafiltered to obtain an extract-containing solution. The molecular weight of the heavy metal binding protein in the viscera of fish and shellfish is several thousand to several tens of thousands, and the molecular weight of the extract component is several tens to several hundreds. Therefore, in order to remove the heavy metal without hindering the recovery of the extract component. Uses a membrane having a molecular weight cutoff of several thousands to 50,000. The material and form of the ultrafiltration membrane are not particularly limited as long as they are within the above range of molecular weight cutoff. For example, it may be a tuber type, a plate and frame type, a spiral type, or a hollow fiber type.

Heavy metal-binding proteins release heavy metals on the acidic side. In addition, hydrolysis proceeds on the alkaline side. From the above, it is necessary to adjust the pH of the extract to a neutral range, specifically pH 3.5 to 9, preferably pH 5 to 8, before ultrafiltration.

Further, according to the knowledge of the present inventors, it is extremely effective to remove heavy metals, especially cadmium, that heat treatment is performed prior to ultrafiltration, and that proteolysis with an enzyme is performed prior to solid-liquid separation. Is. The heat treatment is preferably carried out before the solid-liquid separation in combination. Especially, the removal effect of cadmium is large, and compared to the case without heat treatment (comparison after ultrafiltration) 30
The removal rate can be increased by about%. Specifically, 60
The extract is heat-treated at a temperature range of -100 ° C for 5 minutes to 1 hour.

Enzymatic proteolysis has a unique effect on heavy metal concentrations. That is, the concentrations of zinc and iron in the extract tend to rather increase due to the enzymatic decomposition treatment (comparison after ultrafiltration. The same applies to the following stage). On the other hand, the concentrations of cadmium and copper are temporarily reduced by enzymatic decomposition, but when the enzymatic decomposition progresses excessively, the concentration starts to increase and returns to the level before the decrease. Therefore, it is possible to increase the removal efficiency of cadmium and copper by controlling the progress of enzymatic decomposition. Specific control of the degree of decomposition needs to be carried out according to individual conditions such as the enzyme to be used and its concentration, reaction temperature, protein concentration in the raw material, etc. The termination time of the enzyme reaction may be controlled based on the data.

The proteolytic enzyme (protease) used in the present invention may be appropriately selected from commercially available ones according to the type of extract, pH and treatment temperature. By using these proteolytic enzymes, not only the concentration of heavy metals can be controlled, but also the amount of amino acids in the product is increased,
Also, the composition ratio can be changed.

[0018]

[Examples] In the following, the raw materials of the scallop midgut gland
The present invention will be described in more detail by way of an example of the case (usually referred to as "uro"), but the same applies to other raw materials.

[0019]

Example 1 To 50 g of scallop midgut gland, 150 ml of 50 mM Tris buffer (pH 7.2) was added and homogenized for 1 minute by a high-speed homogenizer. The resulting suspension is 3
After leaving it at room temperature for 0 minutes, it was transferred to a stainless centrifuge tube and heat-treated in boiling water for 15 minutes. This was centrifuged at 10,000 rpm for 15 minutes, and the supernatant was filtered with a filter paper to obtain an extract. 150 ml of the above extract was ultrafiltered using a small ultrafilter (manufactured by Advantech) at a liquid temperature of 25 ° C. and a pressure of 2 kg / cm ² until the concentrated liquid side became 50 ml. As the ultrafiltration membrane, a polysulfone flat membrane having a membrane area of 78.5 / cm ² and a molecular weight cutoff of 10,000 was used. After the analytical sample is dried at 105 ° C, it is wet decomposed with mixed acid (nitric acid / sulfuric acid) and perchloric acid to prepare a sample solution, and the Zn, Cd, Cu and Fe concentrations of the sample solution are measured by an atomic absorption spectrophotometer (Hitachi stock It was measured by a direct suction method using a company-made polarized Zeeman measuring instrument Z6000).

The same analysis was performed on the residue in the extraction process and the ultrafiltration concentrate, and when the results were summed up, the content of heavy metals in 50 g of scallop was Zn: 153.
0 μg, Cd: 1077 μg, Cu: 227 μg, Fe: 15,900
It was μg. The heavy metal removal rate at each step in the present method calculated using this value as the denominator was Zn: 88.7%, Cd: 79.8%, Cu: 65.6% in the extract, respectively.
%, Fe: 89.7%, Zn: 99.3 in ultrafiltrate, respectively
%, Cd: 99.1% or more (concentration in ultrafiltrate: 0.1 ppm or less), Cu: 91.2%, Fe: 99.3%.

[0021]

Example 2 Separation and extraction and heavy metal analysis were carried out in the same manner as in Example 1 except that the heat treatment before centrifugation was not carried out. The heavy metal removal rate in the extraction liquid stage is Z
n: 71.6%, Cd: 45.7%, Cu: 40.5%, Fe: 87.4
%Met.

[0022]

Example 3 By the same method as in Example 1, except that 0.1% of a protease (Protease A-Amano manufactured by Amano Pharmaceutical Co., Ltd.) was added to the suspension before centrifugation and the mixture was allowed to stand at 37 ° C. for up to 120 minutes. Separated extraction and ultrafiltration were performed, and the amount of amino acid at each stage was measured by the PTC amino acid analysis method in which prelabeling was performed with phenylisothiocyanate. At this time, the sample was treated with ethanol to remove the protein component and the amount of free amino acid was measured by a conventional method, and the total amount of amino acid was measured by the sample hydrolyzed with 6N normal hydrochloric acid (110 ° C., 20 hours).

The total amino acid concentration of the extract at 0 minutes of the enzyme reaction was about 1200 mg / 100 ml, and the free amino acid concentration was about 630 mg / 1.
It was 00 ml. The composition of amino acids is
Taurine, glycine, glutamic acid and aspartic acid, and free amino acids contained a large amount of taurine, glycine, alanine and glutamic acid, and the composition was almost similar to that of the scallop scallop. The amino acid concentration in the extract increased with the progress of enzymatic degradation. At 120 minutes of enzymatic reaction, total amino acids were approximately 2800 mg / 100 ml and free amino acids were approximately 1600 mg / 100 ml.
All amino acids except taurine and glycine increased about 3 to 4 times for all amino acids and about 4 to 20 times for free amino acids.

The concentration of free amino acids in the ultrafiltrate increased with enzymatic decomposition as in the case of the extract, and there was almost no difference with the extract. The composition was not significantly different from that in the extract. The total amino acid concentration was about 40% at 0 minutes and about 1 at 120 minutes in comparison with the extract.
The value was 5% lower.

Heavy metal analysis was performed on each of the extract before ultrafiltration and the ultrafiltrate in the same manner as in Example 1. The results are shown in FIGS. Figure 1 (extract)
As shown in Fig. 2 (ultrafiltrate), the heavy metal concentration (pp
The relationship of m) to the progress of the enzymatic reaction (reaction time) is
Zn and Fe are almost proportional, but Cd and Cu are U
It turns out to be a letter shape and has a minimum value in the middle of the reaction.
This peculiar behavior is especially due to heavy metals per mg of total amino acids.
It is clearer in Fig. 3 (extract) and Fig. 4 (ultrafiltrate) showing the decrease in the amount , and the C- and Cu-like J-shapes, and the value in the ultrafiltrate (Fig. 4) is the smallest. The values are remarkably reduced to about 1/5 and 1/3 of the initial values, respectively.

[0026]

INDUSTRIAL APPLICABILITY The ultrafiltration method used in the present invention for removing heavy metals does not require heat energy, and continuous treatment and scale-up can be easily performed by combining a membrane module and a high-pressure liquid feed pump. Therefore, the cost is low. In addition, by combining ultrafiltration and heat treatment and / or enzymatic decomposition, it is possible to remove most of the heavy metals without damaging the extract components, making it safe as a raw material for fertilizers, feeds or natural seasonings. A high fish and shellfish extract can be obtained.

As described above, according to the present invention, it is possible to produce fish shellfish extract from fish shellfish relatively inexpensively and highly safe as a raw material for fertilizer, feed or natural seasoning. Stable use of fishery and stable fishery processing management,
Furthermore, it can be said that it contributes greatly to the environmental protection of the seafood processing area.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between reaction time (min) and heavy metal concentration (ppm) in an extract (before ultrafiltration) when a protease treatment is performed in the method of the present invention.

FIG. 2 is a graph showing the relationship between the reaction time (minutes) and the heavy metal concentration (ppm) in the ultrafiltrate when the protease treatment is performed in the method of the present invention.

FIG. 3 is a graph showing the relationship between the reaction time (min) in the extract (before ultrafiltration) and the heavy metal concentration (μg / mg) relative to all amino acids when the enzyme treatment was performed in the method of the present invention.

It is a graph showing the relationship between the reaction time in ultrafiltrate frames that have undergone proteolytic enzyme treatment and (minute) and the heavy metal concentration to total amino acids (n g / mg) in the method of the present invention; FIG. G

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiromi Kaneko 5-734 Hanazono-cho, Monbetsu-shi, Hokkaido (72) Inventor Tomoki Ota 124-32 (32) Inferior Ebetsu, Hokkaido (72) Nishi Kohei, Monbetsu, Hokkaido Minami-gaoka 4-2-117 (72) Inventor Minoru Kimura 3-8-2 Hanazono-cho, Monbetsu-shi, Hokkaido (56) Reference JP-A-52-125665 (JP, A)

Claims (5)

(57) [Claims] 1. A method for producing a fish and shellfish extract, characterized in that the visceral extract of fish and shellfish is adjusted to pH 3.5 to 9 and ultrafiltration is performed to remove heavy metal components. 2. The method according to claim 1, wherein heat treatment and solid-liquid separation are performed before ultrafiltration. 3. The method according to claim 1 or 2, wherein the extract is treated with a proteolytic enzyme prior to solid-liquid separation. 4. The method according to claim 1, wherein the internal organs of the fish and shellfish are scallop midgut glands. 5. The method according to any one of claims 1 to 4, wherein the internal organs of fish and shellfish is squid liver.