JP4624025B2 - Method for producing food material extract from which harmful heavy metals have been removed - Google Patents

Description

  The present invention relates to a method for removing heavy metals from foods containing harmful heavy metals, and more particularly to a method for providing food material extracts by removing the harmful heavy metals from their extracts.

  By-products, waste liquids, wastes, etc. generated by processing marine foods and marine foods include cadmium and other heavy metals that are harmful to the human body. For example, scallop midgut (uro) and squid viscera (goro) are known to have high cadmium content. These parts may be discarded without being used as food materials. However, it has a high moisture content and tends to rot and deteriorate, causing serious problems such as environmental pollution at processing sites and increased processing costs.

  For this reason, it is necessary to remove these harmful heavy metals in consideration of the environment and food safety and security. Examples of the removal treatment include decomposition of metallothionein by proteolytic enzymes, dissociation of salts by phosphoric acid or sulfuric acid treatment, and precipitation of free metal elements by electrolytic operation.

  However, these methods cannot completely remove heavy metals, and when the residue is used as a fertilizer, there are problems such as remaining heavy metals being mixed from spring water into tap water. Incineration and carbonization processes are also being carried out, but it is difficult to reflect the cost of the product in the price of the product, which puts pressure on production activities and threatens to continue. On the other hand, these marine food processing by-products contain unique aromas and umami ingredients, and it is desired to effectively use and recycle them as food materials.

Patent Document 1 describes a method for removing heavy metals from a heavy metal-containing substance. This method includes bringing a heavy metal-containing material into contact with a phosphoric acid aqueous solution and eluting the heavy metal contained in the heavy metal-containing material into the phosphoric acid aqueous solution. The extract obtained by separating the solid and liquid contains heavy metals and phosphoric acid. Thereafter, this extract is passed through a cation exchange resin column to remove heavy metals. However, the recovered extract still contains phosphoric acid, and a step of removing phosphoric acid is further required for use as a food material extract. Moreover, cation exchange resin is inferior in the removal efficiency of heavy metal, and requires a long time for processing.
JP 2000-296389

  The present invention solves the above-mentioned conventional problems, and the object of the present invention is to provide an efficient method for obtaining a food material extract by removing heavy metals from extracts of foods and food processing by-products, particularly marine foods. It is to provide.

The present invention comprises a step of mixing a food or food processing by-product containing harmful heavy metals with a 0.1 to 10% (w / v) organic acid aqueous solution;
Heating the resulting mixture to 60-110 ° C;
Separating the extract from the heated mixture; and contacting the separated extract with a chelating resin;
And a method for producing a food material extract from which the heavy metal has been removed.

The present invention also includes a step of mixing a food or food processing by-product containing harmful heavy metals with 0.1 to 14% (w / v) aqueous hydrochloric acid;
Heating the resulting mixture to 60-110 ° C;
Separating the extract from the heated mixture;
Neutralizing the separated extract with sodium hydroxide; and contacting the neutralized extract with a chelating resin;
And a method for producing a food material extract from which the heavy metal has been removed.

Furthermore, the present invention includes a step of mixing food or food processing by-products containing harmful heavy metals with water;
Heating the resulting mixture to 60-110 ° C;
Separating the extract from the heated mixture; and contacting the separated extract with a chelating resin;
And a method for producing a food material extract from which the heavy metal has been removed.

  According to the method of the present invention, harmful heavy metals can be almost completely removed only by contacting the extract of food or food processing by-product with a chelate resin, and the extract after treatment contains components harmful to the human body. Does not contain. Therefore, the extract can be used as it is as a food material extract.

  The object of the method of the present invention is foods and food processing by-products containing heavy metals harmful to the human body. Such heavy metals include cadmium, chromium, copper, tin, mercury, manganese, molybdenum, nickel, lead, zinc and the like. The heavy metal referred to in the present invention includes a single heavy metal and a compound thereof.

  Examples of the food include at least one selected from marine products such as fish and shellfish, animals and plants, and examples of the food processing by-product include the internal organs of fish and shellfish that have been discarded so far. For example, the midgut line of the scallop shell (uro) and the squid internal organs (goro) are the targets of the treatment method of the present invention. Furthermore, a by-product generated when the food or food processing by-product is further processed as a raw material is also included in the food processing by-product. For example, a residue obtained by boiling the internal organs of seafood, scallop shells, squid shells and the like to extract aroma components, umami components, and the like are also subject to the treatment method of the present invention.

  In the method of the present invention, first, such food or the like is brought into contact with an organic acid aqueous solution. It is preferable to use an organic acid that is harmless to the human body. This is because if the organic acid is harmless to the human body, it is not necessary to remove the extract in order to use it as a food material extract. Examples of organic acids include acetic acid, citric acid, malic acid, lactic acid, malonic acid, tartaric acid, succinic acid, ascorbic acid and the like. A particularly preferred organic acid is citric acid. These are certified as food additives. In addition, an organic acid may be used independently and may be used in mixture of multiple. For example, a plum extract obtained by boiling plum juice is rich in edible organic acids such as citric acid and can be used as the organic acid referred to in the present invention.

  The concentration of the organic acid aqueous solution is 0.1 to 10% (w / v), preferably 0.1 to 4%, more preferably 1.0 to 4.0%, still more preferably 1.0 to 2.0%. And If the concentration of the aqueous organic acid solution is less than 0.1%, the efficiency for extracting heavy metals from foods and the like is insufficient, and if it exceeds 10%, the efficiency for removing heavy metals from the extract decreases.

  A hydrochloric acid aqueous solution may be used in place of the organic acid aqueous solution. This is because hydrochloric acid is neutralized with sodium hydroxide to form sodium chloride, which can be easily detoxified without removing it. The concentration of the aqueous hydrochloric acid solution is 0.1 to 14% (w / v), preferably 0.6 to 4.0%, more preferably 1.0 to 3.0%, and still more preferably 1.6 to 2.3. %. If the concentration of the hydrochloric acid aqueous solution is less than 0.6%, the efficiency of extracting heavy metals from foods and the like is insufficient, and if it exceeds 4.0%, the efficiency of removing heavy metals from the extract decreases.

  The contact between the food or the like and the acid aqueous solution may be performed in a normal form, but it is preferable to cut the food or the like into an appropriate size or pulverize and mix with the acid aqueous solution. This is because the metal extraction efficiency is improved. In particular, from the viewpoint of metal extraction efficiency, when processing a material that is rich in oily components such as squid, it is preferable to remove these oily components before contacting with an organic acid aqueous solution. .

  The oily component is removed by bringing the target into contact with an organic solvent that is not miscible with water (eg, hexane, ethyl acetate, etc.), and then the residue is mixed with water (eg, acetone, ethyl alcohol, etc.). )). Or it can also carry out by the one-step process which makes a target object contact the organic solvent (for example, acetone, ethyl alcohol, etc.) miscible with water as it is. In general, it is preferable to use an acid aqueous solution having a mixing ratio of food or the like to an acid aqueous solution of about 1 to 10 times the mass 1 of the food.

  The resulting mixture is then heated. Heating is performed by maintaining the mixture at 60 to 110 ° C, preferably 70 to 90 ° C, more preferably 75 to 85 ° C. The heating temperature is appropriately determined within this range depending on the type of food to be treated. In general, when the heating temperature is less than 60 ° C., the metal extraction efficiency decreases or the treatment takes a long time. When the heating temperature exceeds 110 ° C., the colorability of the extract becomes remarkable. The heating time is appropriately determined depending on the heating temperature. From the viewpoint of work efficiency, the heating time is generally 5 to 30 minutes, preferably 10 to 20 minutes, and more preferably 10 to 15 minutes. For example, when the heating temperature is 80 ° C., the desired extraction efficiency can be obtained with a heating time of about 10 to 12.5 minutes.

  After heating, the solid and liquid are separated from the mixture. The separation method is not particularly limited, and a centrifugal separation method, a filtration method, or the like may be used alone or in combination. The separated aqueous solution contains acids added to assist in the extraction of heavy metals, heavy metals extracted from foods before processing, aroma components, umami components, and the like. When hydrochloric acid is used as the acid, the extract is neutralized by adding an equivalent amount of sodium hydroxide.

  If the efficiency of extracting heavy metals from food is not particularly important, organic acids and hydrochloric acid need not be used. This is because it is sufficient to extract a necessary amount of umami components and the like in order to obtain a food extract. In that case, food or the like is mixed with water and heated for a certain period of time, and the extract is separated from the heated mixture. Surprisingly, foods and the like containing heavy metals are eluted with a considerable amount of umami components and heavy metals only by boiling with water. For example, depending on the type of heavy metal, about 50 to 70% of the content may be eluted.

  The heating temperature and heating time may be determined in the same manner as in the case of using an organic acid or the like. The method for separating the solid and liquid from the heated mixture may be performed in the same manner as in the case of using an organic acid or the like.

  In order to remove heavy metals from the liquid extracted from food or the like, the extracted liquid is then brought into contact with a chelate resin. The chelate resin is not particularly limited as long as it is a resin having an iminodiacetic acid group or an iminodipropionic acid group and capable of chelating with a heavy metal ion at a carboxyl group. For example, a chelating resin such as a resin obtained by binding an iminodiacetic acid group or an iminodipropionic acid group to a porous crosslinked polystyrene substrate, a styrene / divinylbenzene copolymer, a carbamic acid resin, or the like is preferable. Specific examples of chelating resins having iminodiacetic acid groups include "Diaion CR11" manufactured by Mitsubishi Chemical Corporation, "Amberlite IRC748" manufactured by Rohm & Haas, "Eporus MX-10" manufactured by Miyoshi Oil & Fats Co., Ltd., and Iminodipropion Specific examples of chelate resins having acid groups include “Eporus MX-8,8C” manufactured by Moritex Co., Ltd., “Sumichel” manufactured by Sumika Chemtex Co., Ltd., “Aclean Z” manufactured by Asahi Glass Engineering Co., Ltd. Examples include “Uniselec UR-10S” manufactured by the company and “Purolite, Levacit” manufactured by Urano Co., Ltd.

  Such chelate resins are heavy metal ions> alkaline earth metal ions> alkali metal ions in terms of metal ion scavenging ability, and have high selectivity for heavy metal ions. Thereby, even if an organic acid or sodium chloride-derived ion is contained in the extract, it is possible to selectively capture heavy metal ions and obtain an extract from which harmful heavy metals have been removed.

  When the extract is acidic, the method of contacting may be neutralized to pH 5.5 to 6.5 with an alkali and then passed through a chelate resin column. If no acid is used in the extraction process, it is not necessary to neutralize the extract. The recovered extract does not contain a component harmful to the human body and can be used as it is as a food material extract.

  The food material extract as used in the present specification refers to a liquid material that may be ingested by the human body in the future. That is, liquids used for raw materials such as processed foods, livestock feeds and agricultural fertilizers are likely to be ingested by the human body in the future, and are included in the food material extract referred to in the present invention. Further, semi-solids and solids obtained by concentrating or drying food material extracts are also included in the scope of the present invention as food materials. Examples of the concentration method and the drying method include an evaporator, a vacuum concentration method using a global concentrator, freeze drying, and spray drying.

  The following examples further illustrate the present invention, but the present invention is not limited thereto.

Reference example 1
The scallop shells from Kushiro were poured into 5 times the amount of water without being refined, mixed, heated to 80 ° C. and heated for 10 minutes. The supernatant was removed by centrifugation and dried to obtain a residue. It was 57.9 ppm (vs dry matter weight) when the cadmium content of the obtained boil residue was measured by the ICP method.

  250 mg of this boil residue was put into 5 ml of a 1% (w / v) aqueous solution of each organic acid shown in Table 1, mixed, heated to 80 ° C. and heated for 10 minutes. The supernatant was removed by centrifugation and passed through a 0.45 μm filter to obtain a filtrate and residue. The residue was washed 3 times with 5 ml of tap water. The filtrate was collected and the pH was adjusted to 5.5.

4 g of a chelate resin having an iminodiacetic acid group (“Diaion CR-11” manufactured by Mitsubishi Chemical Corporation) was filled into a glass tube having a diameter of 1.0 cm, a length of 20 cm, and a volume of 15.7 cm ³ . About 20 ml of the obtained filtrate was added to the chelate resin column and eluted with 20 ml of tap water. The cadmium contents in the filtrate and in the column passage liquid were analyzed by ICP method. The results are shown in Table 1.

[Table 1]

  Almost no cadmium was present in the column passing solution. Moreover, as a result of analyzing the components of the flow-through liquid, it was confirmed that a large amount of inosinic acid and glutamic acid, which are the main roles of umami, and taurine, glycine and alanine, which are the supporting roles of umami, were also included.

Reference example 2
250 mg of the same boil residue used in Reference Example 1 was put into 5 ml of an aqueous citric acid solution having each concentration (w / v) shown in Table 2, mixed, heated to 80 ° C., and heated for 10 minutes. The supernatant was removed by centrifugation and passed through a 0.45 μm filter to obtain a filtrate and residue. The residue was washed 3 times with 5 ml of tap water. The filtrate was collected and the pH was adjusted to 5.5.

4 g of a chelate resin having an iminodiacetic acid group (“Diaion CR-11” manufactured by Mitsubishi Chemical Corporation) was filled into a glass tube having a diameter of 1.0 cm, a length of 20 cm, and a volume of 15.7 cm ³ . About 20 ml of the obtained filtrate was added to the chelate resin column and eluted with 20 ml of tap water. The cadmium contents in the filtrate and in the column passage liquid were analyzed by ICP method. The cadmium contents in the filtrate and in the column passage liquid were analyzed by ICP method. The results are shown in Table 2.

[Table 2]

  The removal efficiency of cadmium was not affected by the concentration of citric acid, and almost no cadmium was present in the column passing solution. Moreover, as a result of analyzing the components of the flow-through liquid, it was confirmed that a large amount of inosinic acid and glutamic acid, which are the main roles of umami, and taurine, glycine and alanine, which are the supporting roles of umami, were also included.

Comparative Reference Example 1
The filtrate was brought into contact with the resin in the same manner as in Reference Example 2 except that a cation exchange resin ("Diaion SK110" manufactured by Mitsubishi Chemical Corporation) was used instead of the chelate resin having an iminodiacetic acid group, and the column-passed solution was used. Obtained. The cadmium contents in the filtrate and in the column passage liquid were analyzed by ICP method. The results are shown in Table 3.

[Table 3]

  The removal efficiency of cadmium was 0.02% or less.

Reference example 3
250 mg of the same boil residue used in Reference Example 1 was put into 5 ml of hydrochloric acid aqueous solution having each concentration (w / v) shown in Table 4, mixed, heated to 80 ° C., and heated for 10 minutes. The supernatant was removed by centrifugation and passed through a 0.45 μm filter to obtain a filtrate and residue. The residue was washed 3 times with 5 ml of tap water.

The filtrate was collected and neutralized by adding 0.1 to 2.0 N aqueous sodium hydroxide solution thereto. 4 g of a chelate resin having an iminodiacetic acid group (“Diaion CR-11” manufactured by Mitsubishi Chemical Corporation) was filled into a glass tube having a diameter of 1.0 cm, a length of 20 cm, and a volume of 15.7 cm ³ . About 20 ml of the obtained filtrate was added to the chelate resin column and eluted with 20 ml of tap water. The cadmium contents in the filtrate and in the column passage liquid were analyzed by ICP method. The cadmium content in the filtrate (before neutralization) and in the column passage liquid was analyzed by the ICP method. The results are shown in Table 4.

[Table 4]

  The removal efficiency of cadmium was not affected by the concentration of hydrochloric acid, and almost no cadmium was present in the column passing solution. Moreover, as a result of analyzing the components of the flow-through liquid, it was confirmed that a large amount of inosinic acid and glutamic acid, which are the main roles of umami, and taurine, glycine and alanine, which are the supporting roles of umami, were also included.

Comparative Reference Example 2
The neutralized filtrate was brought into contact with the resin in the same manner as in Reference Example 3 except that a cation exchange resin ("Diaion SK110" manufactured by Mitsubishi Chemical Corporation) was used instead of the chelate resin having iminodiacetic acid groups, and the column was contacted. A passing liquid was obtained. The cadmium contents in the filtrate and in the column passage liquid were analyzed by ICP method. The results are shown in Table 5.

[Table 5]

  The removal efficiency of cadmium was 0.04% or less.

Reference example 4
Squid goro from Wakayama Prefecture was dipped in 3 times the volume (v / w) of acetone, crushed finely and left overnight. The mixture was filtered using 1G3 filter paper, and the residue was washed with acetone until the liquid was clear and the residue became powder. The obtained residue was poured into 5 times the amount of water, mixed, heated to 80 ° C. and heated for 10 minutes. The supernatant was removed by centrifugation and dried to obtain a residue. It was 124.6 ppm (vs dry matter weight) when the cadmium content of the obtained boil residue was measured by ICP method.

A filtrate was obtained in the same manner as in Reference Example 2 except that the obtained Ikagoro boil residue was used instead of the scallop boil residue, and this filtrate was brought into contact with a chelate resin to obtain a column passing solution. The cadmium contents in the filtrate and in the column passage liquid were analyzed by ICP method. As shown in Table 6, the same results as in Reference Example 2 were obtained.

[Table 6]

Reference Example 5
A neutralized filtrate was obtained in the same manner as in Reference Example 3 except that the Ikagoro boil residue obtained in Reference Example 4 was used instead of the scallop boil residue, and this filtrate was brought into contact with a chelate resin. A column passing solution was obtained. The cadmium content in the filtrate (before neutralization) and in the column passage liquid was analyzed by the ICP method. As shown in Table 7, the same results as in Reference Example 3 were obtained.

[Table 7]

Example 1
The scallop shells from Kushiro were poured into 5 times the amount of water without being refined, mixed, heated to 80 ° C. and heated for 10 minutes. The precipitate was removed by centrifugation, and a supernatant was obtained. When the cadmium content of the obtained supernatant was measured by the ICP method, it was 145.0 ppm (weight to dry matter). This elution amount corresponds to about half of the total cadmium contained in scallops.

4 g of a chelate resin having an iminodiacetic acid group (“Diaion CR-11” manufactured by Mitsubishi Chemical Corporation) was filled into a glass tube having a diameter of 1.0 cm, a length of 20 cm, and a volume of 15.7 cm ³ . About 20 ml of the obtained supernatant was added to the chelate resin column and eluted with 20 ml of tap water. The cadmium content in the column passage liquid was analyzed by ICP method. The result was less than 0.1 ppm.

  Almost no cadmium was present in the column passing solution. Moreover, as a result of analyzing the components of the flow-through liquid, it was confirmed that a large amount of inosinic acid and glutamic acid, which are the main roles of umami, and taurine, glycine and alanine, which are the supporting roles of umami, were also included.

Example 2
Squid goro from Wakayama Prefecture was dipped in 3 times the volume (v / w) of acetone, crushed finely and left overnight. The mixture was filtered using 1G3 filter paper, and the residue was washed with acetone until the liquid was clear and the residue became powder. The obtained residue was poured into 5 times the amount of water, mixed, heated to 80 ° C. and heated for 10 minutes. The precipitate was removed by centrifugation, and a supernatant was obtained. It was 67.1 ppm (vs dry matter weight) when the cadmium content of the obtained supernatant was measured by the ICP method. This amount of elution corresponds to about half of the total amount of cadmium contained in Ikagoro.

4 g of a chelate resin having an iminodiacetic acid group (“Diaion CR-11” manufactured by Mitsubishi Chemical Corporation) was filled into a glass tube having a diameter of 1.0 cm, a length of 20 cm, and a volume of 15.7 cm ³ . About 20 ml of the obtained supernatant was added to the chelate resin column and eluted with 20 ml of tap water. The cadmium content in the column passage liquid was analyzed by ICP method. The result was less than 0.1 ppm.

  Almost no cadmium was present in the column passing solution. Moreover, as a result of analyzing the components of the flow-through liquid, it was confirmed that a large amount of inosinic acid and glutamic acid, which are the main roles of umami, and taurine, glycine and alanine, which are the supporting roles of umami, were also included.

Claims (6)

Mixing food or food processing by-products containing cadmium with water;
Heating the resulting mixture to 70-90 ° C. for 5-30 minutes ;
Separating the extract from the heated mixture; and contacting the separated extract with a chelating resin;
A method for producing a food material extract from which cadmium has been removed. The method according to claim 1, wherein the heating temperature of the mixture is 75 to 85 ° C. The method according to claim 1, wherein the heating time of the mixture is 10 to 20 minutes. The method according to any one of claims 1 to 3, wherein the food or food processing by-product is scallop shell or squid shell. The method according to claim 1, wherein the food or food processing by-product is scallop uro. The method according to any one of claims 1 to 5, wherein 50 to 70% of cadmium is eluted from a food or a food processing byproduct containing cadmium by the heating step.