JP7590253B2 - Manufacturing method for reduced iodine kelp - Google Patents

Description

The present invention relates to a method for producing edible kelp with reduced iodine content.

It is generally known that edible kelp contains a lot of iodine. Although iodine is an important mineral for life, the Ministry of Health, Labor and Welfare has published standards for the amount of iodine that should be consumed, including recommended intake amounts and upper limits. Excessive iodine intake can lead to thyroid-related diseases such as hypothyroidism, goiter, and thyrotoxicosis, so there are many voices calling for a reduction in the amount of iodine in edible kelp.

For example, Patent Document 1 discloses a method for producing edible kelp with reduced iodine content by immersing raw kelp in water heated to 60-100°C for 3-30 minutes to dissolve the iodine.

JP 2015-136348 A

However, the manufacturing method described in Patent Document 1 was unable to sufficiently reduce iodine, and the kelp after the iodine reduction lost its shape and yield was poor.

Therefore, the present invention aims to provide a method for producing iodine-reduced kelp that can sufficiently reduce iodine while maintaining the texture, etc., and that improves yield without causing the kelp to lose its shape after the iodine has been reduced.

[1] That is, the present invention is a method for producing reduced-iodine kelp, which comprises a first step of soaking kelp raw seaweed in an aqueous solution containing a mixture of calcium salt and glycine, and a second step of soaking the raw seaweed in water after the first step.

[2] The method for producing reduced iodine kelp described in [1] above is characterized in that boiling is performed in at least one of the first step or the second step.

[3] The method for producing reduced iodine kelp described in [2] above is characterized in that the boiling time is 2 to 10 minutes.

According to the present invention, it is possible to sufficiently reduce the iodine content in edible kelp while maintaining the texture, etc., and this has the remarkable effect of improving the yield without causing the kelp to lose its shape after the iodine has been reduced.

The following is a detailed explanation of an embodiment of the method for producing iodine-reduced kelp according to the present invention. Note that when a range is indicated in the explanation, it includes an upper and lower limit.

[Kombu's original algae]
The raw seaweed of kelp used in the method for producing kelp with reduced iodine of the present invention is a large seaweed belonging to the brown algae family Laminariales, and is preferably Ma-Konbu (true seaweed), Oni-Konbu (Rausu seaweed), Risori-Konbu (Rishiri seaweed), Hosome-Konbu (fine-grained seaweed), Mitsuishi-Konbu (Mitsuishi seaweed, Hidaka seaweed), Naga-Konbu (long-grained seaweed), Gagome (basket-weed seaweed), etc. One or more of these raw seaweeds can be used in combination. When used in the present invention, raw seaweed of kelp in a dried state is preferable, but it may also be rehydrated raw seaweed.

[Calcium salts]
The calcium salt used in the method for producing kelp with reduced iodine content of the present invention is an organic or inorganic salt of calcium. When the raw seaweed of kelp is soaked in an aqueous solution of calcium salt, especially when boiled, it can prevent the kelp from losing its shape, such as becoming mushy or squishy, and thus improve the yield of the kelp used. In addition, the calcium salt used is preferably at least one selected from calcium chloride, calcium citrate, calcium hydroxide, calcium carbonate, calcium lactate, and calcium sulfate.

The concentration of the aqueous calcium salt solution when treating the raw kelp seaweed is preferably 0.1 to 5% by weight, and more preferably 0.5 to 3% by weight. When the concentration of the aqueous calcium salt solution is in this range, it is possible to sufficiently prevent the treated kelp from losing its shape.

〔glycine〕
Glycine used in the method for producing kelp with reduced iodine content of _{the present invention is an amino acid with the rational formula H2NCH2COOH .} When raw kelp seaweed is soaked in an aqueous solution of glycine, a larger amount of iodine contained in the kelp can be eluted.

The concentration of the glycine solution when treating the raw kelp seaweed is preferably 0.1 to 5% by weight, and more preferably 0.5 to 3% by weight. When the concentration of the glycine solution is in this range, the iodine contained in the kelp can be sufficiently eluted.

The kelp raw algae is then soaked and boiled in the aqueous solution containing the calcium salt and glycine. This allows the iodine to be sufficiently reduced while maintaining the texture, etc., compared to processing in multiple steps with an aqueous solution containing only calcium salts or only glycine, and prevents the kelp raw algae from losing its shape after the iodine has been reduced.

The method for producing the reduced iodine dried kelp of the present invention is described below.

[First step (S1)]
The first step is a step of immersing the raw kelp algae in an aqueous solution containing a sufficient amount of a calcium salt and glycine in order to elute iodine and the like contained in the raw kelp algae. More preferably, This is a process in which the raw kelp seaweed is immersed in hot water boiled at 80 to 100°C for 2 to 10 minutes. By setting the elution temperature at 80 to 100°C, iodine can be eluted quickly. First process In this case, it is preferable to reduce the amount of iodine contained in the raw kelp by 90%, and more preferably by 95%.

[Second step (S2)]
The second step is a step of soaking the raw kelp in water after the first step in order to elute iodine and the like contained in the raw kelp. More preferably, the raw kelp taken out after the first step is This is a process in which the raw kelp is soaked in hot water at 80-100℃ for 2-10 minutes. Generally, if the raw kelp is soaked in hot water more than twice, it will lose its shape and the yield will decrease. However, since an aqueous solution containing calcium salt is used in the first step, the kelp raw seaweed is less likely to lose its shape even if it is immersed in hot water in the second step. In this embodiment, it is preferable to carry out the second step once, but in other embodiments, the second step may be carried out multiple times, i.e., two or more times.

[Drying process (S3)]
The drying process is a process in which the raw kelp is taken out after the first or second process, and excess water is evaporated. Specifically, it can be dried in the sun, exposed to warm or hot air, or dried under reduced pressure. The drying is carried out by heating, leaving it to stand indoors and allowing it to dry naturally, etc. The drying step is not essential in the present invention and is carried out as necessary.

Furthermore, after the first or second step, or after the drying step, a step of seasoning the extracted kelp raw seaweed with various seasoning liquids can be added.

The following provides a detailed explanation of the embodiments of the present invention.

Example 1
[First step]
After removing foreign matter adhering to the surface, 50 g of raw kelp, which is long kelp produced in Nemuro, was immersed in 950 ml of boiling water containing an aqueous solution of 1% by weight calcium chloride and 1% by weight glycine, and boiled for 5 minutes. The raw kelp was then placed in a colander and left to stand to drain.

[Second step]
The raw kelp seaweed extracted after the first step was immersed in 950 ml of boiling water and boiled for 5 minutes. After that, the raw kelp seaweed was placed in a colander and left to stand to drain the water.

[Drying process]
After the second step, the mixture was spread out on a net, left to stand, and dried with hot air until the moisture content reached about 10% by weight.

Through these processes, we obtained raw kelp seaweed with reduced iodine content.

<Comparative Example 1>
A kelp raw algae with reduced iodine content was obtained in the same manner as in Example 1, except that a 1 wt % aqueous glycine solution was used in the first step and a 1 wt % aqueous calcium chloride solution was used in the second step.

<Comparative Example 2>
A raw alga of kelp with reduced iodine content was obtained in the same manner as in Example 1, except that a 1 wt % aqueous calcium chloride solution was used in the first step and a 1 wt % aqueous glycine solution was used in the second step.

<Reference Example>
A raw seaweed of kelp with reduced iodine content was obtained in the same manner as in Example 1, except that water was simply used in the first step and the second step was not carried out.

The iodine content of the kelp raw seaweed obtained in Example 1, Comparative Examples 1-2, and Reference Example was measured, and the extent to which the iodine content was reduced relative to the raw seaweed of the raw kelp was calculated as the removal rate. Specifically, the amount of iodine contained in the kelp raw seaweed before and after treatment was measured based on the following combustion ion chromatography method in accordance with JIS K0127, JIS K0102, and JIS Z73026. That is, first, the kelp raw seaweed was weighed, and combustion was performed using a combustion device (manufactured by Nitto Seiko Analytech Co., Ltd., model number: AQF-100), the residue was transferred to a measuring flask, and water was added to dilute it to a predetermined amount, and the aqueous solution was analyzed by ion chromatography (manufactured by Thermo Scientific Co., Ltd., model number: ICS-1600), and the amount of iodine in the kelp raw seaweed was quantified by comparison with a 1000 mg/L iodine ion standard solution, etc. The removal rate was then calculated from the obtained iodine content.

Then, the yield of the kelp raw algae obtained in Example 1, Comparative Examples 1 and 2, and Reference Example was calculated. In other words, the yield was calculated as the ratio of the weight of the kelp raw algae finally obtained to the weight of the kelp raw algae used in the treatment.

Then, the texture of the kelp raw seaweed obtained in Example 1 and Comparative Examples 1 and 2 was evaluated. Specifically, when a sensory evaluation was performed using the Reference Example as a standard, samples that were as hard as the Reference Example and could be easily chewed were rated as ○, samples that were slightly hard but could be chewed were rated as △, and samples that were hard and difficult to chew were rated as ×.

Then, the taste of the raw kelp seaweed obtained in Example 1 and Comparative Examples 1 and 2 was evaluated. Specifically, when a sensory evaluation was performed using the Reference Example as the standard, those that retained the same flavor as the Reference Example were rated as ○, those whose flavor was impaired were rated as △, and those whose flavor was significantly impaired were rated as ×.

These results are shown in Table 1.

As shown in Table 1, the manufacturing method of Example 1, compared to Comparative Examples 1 and 2, was able to sufficiently reduce iodine by removing more than 95% while maintaining the same texture and taste as the reference example using only water, and it was found that the kelp did not lose its shape and the yield was improved.

Claims (3)

A first step of soaking kelp raw seaweed in an aqueous solution containing a calcium salt and glycine;
A second step of immersing the substrate in water after the first step;
A method for producing reduced iodine kelp, comprising the steps of: The method for producing reduced iodine kelp according to claim 1, characterized in that boiling is performed in at least one of the first step or the second step. The method for producing reduced iodine kelp described in claim 2, characterized in that the boiling time is 2 to 10 minutes.