Method for removing arsenic in sargassum

Abstract

The present invention relates to a method for reducing arsenic in Sargassum, which includes a pressurized treatment step without heat treatment, thereby effectively removing arsenic while reducing energy consumption due to heat treatment or the possibility of destruction and deformation of various useful components of Sargassum, and enables processing in large quantities within a short period of time.

Description

Technology Field

[0001] The present invention relates to a method for reducing arsenic in Sargassum. Background Technology

[0003] Recently, research on natural products with various physiological activities is being actively conducted not only on terrestrial organisms but also on marine organisms. Among marine organisms, seaweed has unique metabolic processes that are not found in terrestrial organisms due to the unique environment of the marine ecosystem, so research is actively being conducted to identify various physiological activities and components related to this.

[0004] There are approximately 36,000 species of seaweed distributed across the globe, and it is estimated that about 1,000 species of seaweed inhabit Korea. They are recognized as important marine biological resources in terms of ecology and economy, mainly in East Asia, and research on ways to utilize them is actively underway.

[0005] Seaweed is not only very low in calories and rich in various minerals, dietary fiber, and amino acids, but also contains large amounts of mucilaginous polysaccharides such as laminarin, alginic acid, and fucoidan, which are not found in terrestrial plants (embryos). As the diverse physiological activities of seaweed extracts have been identified, they are being developed as biohealthcare application products for use in health foods, cosmetics, and pharmaceuticals. In particular, fucoidan, which is gaining attention as a physiologically active component of brown seaweeds such as wakame and kelp, exhibits anticoagulant effects, promotes the healing of gastric ulcers, has antibacterial effects, inhibits blood pressure increase, induces hepatocyte growth factor (HGF) production, inhibits blood sugar increase, regulates immune cells, has anti-allergic effects, and has antiviral effects. It has been reported to have excellent effects, particularly in the treatment of cancers of the digestive system, and is also reported to have very excellent effects in the treatment of most types of cancer.

[0006] Hijiki, a brown algae along with wakame and kelp S. fusiformeHizikia fusiformis belongs to the genus Sargassum in the family Sargassumaceae and is mainly found or cultivated along the southern coast of Korea, including Wando and Jeju, as well as in Japan. It is an alkaline food that is not only rich in nutrients among seaweeds but also contains abundant minerals such as calcium and iron compared to other food ingredients, and is a natural health food containing large amounts of polysaccharides such as alginic acid and fucoidan. Although Hizikia fusiformis is gaining attention as a health food ingredient, it has been reported to contain a certain level of arsenic, which is known as an environmental pollutant.

[0007] Meanwhile, arsenic (As) is a naturally occurring element widely distributed in the Earth's crust that exists in various forms of compounds. It is classified as a highly hazardous heavy metal, categorized as Group 1—alongside cadmium (Cd)—by the International Agency for Research on Cancer (IARC), an agency under the World Health Organization (WHO), as it is classified as a substance carcinogenic to humans. The danger posed by arsenic is managed at a high level, to the extent that it has ranked first in the U.S. Environmental Protection Agency (EPA)'s priority list for hazardous environmental pollutants for several years. Furthermore, arsenic and its compounds are registered as Class 1 carcinogens in the list of carcinogens compiled by the Korea Occupational Safety and Health Agency. Chemically, arsenic is classified as a metalloid; depending on its chemical form, it is divided into inorganic arsenic (iAs), which is combined with oxygen, chlorine, and sulfur, and organic arsenic (oAs), which is combined with carbon and hydrogen. The degree of human health risk and toxicity varies depending on the ionic state and the form of the compound.

[0008] Technologies for reducing or removing arsenic present in nature have been developed using arsenic adsorbents and ion exchange resins, limited to arsenic present in soil or water. Conventional technologies for removing or reducing arsenic from seaweed, such as *Hijiki*, rely on physical methods (soaking, heat treatment, etc.) or chemical methods (chelating agents, organic acids, etc.) in accordance with domestic standards. Existing methods for removing arsenic from seaweed can result in the loss of effective components due to thermal deformation, consume a large amount of energy when applied to large-scale processes, and cause significant wastewater problems; therefore, there is a need for an efficient arsenic removal method that can overcome these issues. Prior art literature

[0010] Korean Patent Publication No. 2021-0075528 The problem to be solved

[0011] The present invention aims to provide an arsenic reduction method that can effectively remove arsenic from Sargassum while minimizing the loss of active ingredients. means of solving the problem

[0013] 1. A method for reducing arsenic in Sargassum, comprising the steps of immersing raw Sargassum in an aqueous solvent and pressurizing it.

[0014] 2. A method for reducing arsenic in Sargassum, wherein the above Sargassum is one or more species selected from the group consisting of Sargassum fusiforme, Sargassum horneri, Sargassum serrations, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, or Sargassum fusiforme.

[0015] 3. A method for reducing arsenic in Sargassum, wherein the weight ratio of the aqueous solvent to the total weight of the Sargassum raw material is 1:30 to 1:60 in accordance with 1 above.

[0016] 4. A method for reducing arsenic in Sargassum, wherein the aqueous solvent in accordance with 1 above comprises an organic acid.

[0017] 5. A method for reducing arsenic in Sargassum, wherein the organic acid in 4 above is malic acid, citric acid, tartaric acid, oxalic acid, ascorbic acid, or gluconic acid.

[0018] 6. A method for reducing arsenic in Sargassum according to 4, wherein the organic acid in the aqueous solvent is 0.001% to 0.1% (w / v).

[0019] 7. A method for reducing arsenic in Sargassum, wherein the pressurization treatment in accordance with 1 above is performed at 3000 bar to 6000 bar.

[0020] 8. A method for reducing arsenic in Sargassum, wherein the pressurization treatment inversely proportional to the applied pressure is performed for 5 to 120 minutes in accordance with 7 above. Effects of the invention

[0022] The method for reducing arsenic in Sargassum according to the present invention is an eco-friendly and efficient method that reduces heat energy consumption due to heating and water pollution load caused by wastewater generation, and can enhance food safety by effectively removing arsenic while minimizing the loss of active ingredients in Sargassum. Brief explanation of the drawing

[0024] Figure 1 shows the pretreatment method and analysis conditions for heavy metal analysis of seaweed (Hijiki) using microwave decomposition and ICP-OES. Figure 2 shows the pretreatment conditions and instrumental analysis conditions of HLPC-ICP / MS for the analysis of arsenic chemical species in seaweed (Hijiki). Figure 3 is a graph showing the standard calibration curves of six arsenic chemical species detected as a result of analysis using HLPC-ICP / MS. Figure 4 is an HPLC-ICP-OES chromatogram of standard solutions of six arsenic chemical species (top) and the seaweed *Hijiki* (bottom). Figure 5 illustrates the experimental method for reducing arsenic in seaweed *Hijiki* according to heat treatment temperature conditions. Figure 6 is a graph showing the arsenic reduction behavior of the seaweed *Hijiki* according to heat treatment temperature conditions ((a) 40℃; (b) 60℃; (c) 80℃; (d) 95℃). Figure 7 is a graph showing the results of arsenic reduction in the seaweed *Hijiki* according to the heat treatment temperature. Figure 8 illustrates the experimental method for reducing arsenic in the seaweed *Hijiki* according to acid treatment conditions. Figure 9 is a graph showing the arsenic reduction results of the seaweed *Hijiki* according to acid treatment conditions ((a) hydrochloric acid; (b) nitric acid; (c) citric acid; (d) malic acid; (e) tartaric acid; (f) oxalic acid). Figure 10 illustrates the experimental method for reducing arsenic in the seaweed *Hijiki* according to ultra-high pressure non-heating treatment conditions. Figure 11 is a graph showing the arsenic reduction results of the seaweed *Hijiki* under ultra-high pressure non-heating treatment conditions ((a) 4000 bar; (b) 5000 bar). Specific details for implementing the invention

[0025] The present invention will be described in detail below.

[0027] The present invention relates to a method for reducing arsenic in Sargassum, comprising the steps of immersing raw Sargassum in an aqueous solvent and applying pressure.

[0028] The above-mentioned Sargassum may be used without restriction as long as it is a seaweed belonging to the genus Sargassum. For example, the above-mentioned Sargassum may be *Hijiki*, *Sargassum horneri*, *Sargassum serrated*, *Sargassum tectorum*, *Sargassum fusiforme*, *Sargassum fusiforme*, *Sargassum fusiforme*, *Sargassum fusiforme*, *Sargassum fusiforme*, *Sargassum fusiforme*, or *Sargassum fusiforme*, and specifically, it may be *Hijiki*.

[0029] In this specification, the terms "raw material" and "raw material" are used interchangeably and refer to a state in which the material has been harvested and has not yet been processed. Materials that have been dried and then crushed or are in powder form are not included within the meaning of "raw material," but a harvested and dried state or a cut state thereof may be included within the meaning of "raw material." The cutting may be a cutting method that does not significantly damage the original form of the raw material, rather than a finely chopped cut.

[0030] Aqueous solvents can be water.

[0031] The weight ratio of the aqueous solvent to the total weight of the above-mentioned Sargassum raw material can be appropriately selected by a person skilled in the art as a ratio usable in food processing in the industry. For example, the weight ratio may be 1:20 to 1:80, 1:20 to 1:70, 1:30 to 1:60, 1:30 to 1:50, 1:35 to 1:45, etc., but is not limited thereto.

[0032] The above-mentioned aqueous solvent may contain an organic acid. The above-mentioned organic acid may be used without restriction as long as it is an organic acid that is available in the industry as a food additive in the domestic Food Code for use in food processing. For example, the above-mentioned organic acid may be malic acid, citric acid, tartaric acid, oxalic acid, ascorbic acid, gluconic acid, acetic acid, citric acid, formic acid, fumaric acid, etc., but is not limited thereto. In addition, the above-mentioned organic acid may be a food additive registered and authorized for use in the 2022 Ministry of Food and Drug Safety "Standards and Specifications for Food Additives" notification, and may be an organic acid with proven safety that does not require the establishment of an Acceptable Daily Intake (ADI). For example, it may be malic acid, citric acid, tartaric acid, ascorbic acid, or gluconic acid, but is not limited thereto.

[0033] The content of the organic acid in the above aqueous solvent can be appropriately selected by a person skilled in the art to a suitable degree for reducing arsenic in Sargassum. For example, the organic acid (w / v) in the above aqueous solvent may be 0.0001% to 5%, 0.0005% to 3%, 0.001% to 1%, 0.001% to 0.5%, 0.001% to 0.3%, 0.001% to 0.1%, 0.003% to 0.1%, 0.005% to 0.1%, or 0.01% to 0.1%, but is not limited thereto.

[0034] The above-mentioned pressurization treatment can be performed under non-heating conditions. Pressurization treatment under non-heating conditions can minimize the deterioration of the inherent quality of food—that is, physical and chemical changes occurring during heat treatment, such as the destruction of nutrients, changes in physical properties, non-enzymatic browning, vitamin destruction, and loss of natural flavor—while largely maintaining the advantages of general heat treatment, such as protein denaturation, starch gelatinization, enzyme inactivation, and sterilization during food cooking and processing. The pressurization treatment under non-heating conditions in the present invention can reduce arsenic with high efficiency while minimizing changes in the external shape of Sargassum (e.g., loss), tissue destruction, and loss or deformation of active ingredients.

[0035] The above pressurization treatment may be performed under pressure conditions typically applied in the industry when utilizing physical non-heating technology. A pressure suitable for reducing arsenic in Sargassum may be appropriately selected by a person skilled in the art. For example, the above pressurization treatment may be performed at 1000 bar to 6000 bar, 1500 bar to 6000 bar, 2000 bar to 6000 bar, 2500 bar to 6000 bar, 3000 bar to 6000 bar, 3000 bar to 5000 bar, and 4000 bar to 5000 bar, but is not limited thereto.

[0036] The above pressurization time can be appropriately selected by a person skilled in the art in inverse proportion to the applied pressure. The higher the pressure, the shorter the time required for processing. The above pressurization time may be, for example, 5 to 120 minutes, 5 to 100 minutes, 5 to 90 minutes, 5 to 80 minutes, 5 to 70 minutes, 5 to 60 minutes, or 9 to 60 minutes, but is not limited thereto. Specifically, when a pressure of 3,000 bar to 4,000 bar is applied, pressurization can be performed for 60 to 120 minutes; when a pressure of 4,000 bar to 5,000 bar is applied, pressurization can be performed for 9 to 60 minutes; and when a pressure of 5,000 bar to 6,000 bar is applied, pressurization can be performed for 5 to 9 minutes. Additionally, the above pressurization time may be performed in several stages. The number of times may be appropriately selected by a technician in accordance with the surrounding environment or conditions during pressurization treatment (e.g., safety limit settings of the device, etc.). For example, when a pressure of 3,000 bar to 4,000 bar is applied, pressurization treatment may be performed in two steps; when a pressure of 4,000 bar to 5,000 bar is applied, pressurization treatment may be performed in two or three steps; and when a pressure of 5,000 bar to 6,000 bar is applied, pressurization treatment may be performed in three or more steps, but is not limited thereto.

[0037] The arsenic in the above Sargassum may include various forms of compounds containing arsenic. For example, the arsenic may include inorganic arsenic or organic arsenic. The inorganic arsenic may be trivalent arsenic (AsⅢ, arsenite) and pentavalent arsenic (AsⅤ, arsenate), and the organic arsenic may be monomethyl arsenate (MMA, monomethyl arsenate), dimethyl arsenate (DMA, dimethyl arsenate), arsenobetaine (AsB, arsenobetaine), arsenocholine (AsC, arsenocholine), and various arsenosugars and arsenolipids.

[0038] Through the arsenic reduction method of the present invention, a significant amount of arsenic in Sargassum can be reduced, specifically, total arsenic can be reduced by more than 85% and inorganic arsenic by more than 95%.

[0039] In this specification, the terms "reduction" and "removal" are used interchangeably and mean lowering or reducing. In this specification, when used in conjunction with "arsenic," it means lowering or reducing the amount of arsenic contained in Sargassum, seaweed (Hijiki), etc. (e.g., the total amount of arsenic contained in various forms of arsenic compounds, inorganic arsenic, etc.).

[0041] Hereinafter, in order to specifically explain the present invention, it will be described in detail with reference to examples.

[0043] Example 1. Analysis of heavy metal and inorganic arsenic content in raw seaweed (Hijiki).

[0044] <1-1> Analysis of Heavy Metal Content in Raw Seaweed (Hijiki)

[0045] To confirm the arsenic reduction effect of seaweed Hizikia fusiforme according to each treatment condition in the examples described below regarding the heavy metal content including arsenic in raw Hizikia fusiforme, an experiment was conducted as follows. For the analysis of heavy metals including arsenic in food, microwave digestion and inductively coupled plasma-optical spectroscopy (ICP-OES) were used in accordance with the "Guidelines for Test Methods for Heavy Metals in Food" published by the Ministry of Food and Drug Safety in June 2019.

[0046] Precisely weigh 0.1 g of the raw (dried) Hijiki and the dried Hijiki sample after arsenic reduction according to each treatment condition, transfer them to a microwave-specific vessel, add 7 mL of 70% nitric acid solution (HNO3) and 1 mL of 30% hydrogen peroxide (H2O2), and after preliminary decomposition at room temperature, use a microwave decomposition device (MARS TM Digestion was performed using a microwave decomposition device (5, CEM, Matthews, NC, USA). To ensure complete decomposition of organic matter in the sample, the temperature program of the microwave decomposition device was set to increase to 80°C over 5 minutes under 1000 W conditions, then lower to 50°C over 5 minutes, and then raise to 190°C over 15 minutes and maintain for 20 minutes. After the reaction was completed, the container was cooled sufficiently, the walls of the container were washed with distilled water, and the volume was adjusted to a final of 50 g in a 50 mL centrifuge tube with tertiary purified water (18.2 mΩ).

[0047] Heavy metals in the test solution were analyzed using an Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES, 720-ES, Agilent, Santa Clara, CA, USA), which analyzes specific elements by spectroscopically analyzing radiation emitted until the excited atoms return to the ground state after desolvation, atomization, and excitement using argon (Ar) inductively coupled plasma (Fig. 1). For the heavy metal content in seaweed, a multi-element calibration standard (PerkinElmer, Waltham, MA, USA) was prepared by stepwise diluting a stock solution of arsenic, lead, and cadmium with 14% nitric acid solution (HNO3) to concentrations ranging from 1 to 100 mg / L. The samples were then analyzed under the same conditions as the test solution, and a standard calibration curve was constructed to calculate the correlation coefficient (R²). 2 Quantitative analysis was performed after confirming linearity of 0.999 or higher.

[0048] To ensure the reliability of the experimental results, accuracy was confirmed by comparing the certified values ​​with the recovery rates after analyzing the samples in the same manner using a certified reference material (CRM 7405-a, NMIJ, Ibaraki, Japan) with a similar physical and chemical composition (Table 1). As a result of analyzing heavy metals in commercially available dried sea tangle, cadmium (Cd) and lead (Pb) were not detected, while arsenic was confirmed to be in the range of 124.49–172.09 mg / kg dry weight, with an average of 141.56±26.60 mg / kg dry weight (Table 2).

[0049] [Table 1]

[0050]

[0051] [Table 2]

[0052]

[0054] <1-2> Separation of Arsenic Chemical Species and Analysis of Inorganic Arsenic Content in Raw Seaweed (Hijiki)

[0055] To confirm the inorganic arsenic reduction effect of the seaweed *Hijiki*, the inorganic arsenic analysis method was used by separating and analyzing five types of arsenic chemical species using HPLC-ICP / MS combined with high performance liquid chromatography and inductively coupled plasma-mass spectrometry, referencing the "Practical Guide to Inorganic Arsenic Test Methods" published by the Ministry of Food and Drug Safety in March 2017, and the content of inorganic arsenic (iAs) was confirmed as the sum of trivalent arsenic (arsenite, AsⅢ) and pentavalent arsenic (arsenate, AsⅤ).

[0056] For the analysis of inorganic arsenic in the seaweed *Hijiki*, approximately 1 g of a homogenized sample was taken, 5 mL of 1% nitric acid solution (HNO3)-50% methanol (MeOH) was added, and the mixture was heated and extracted in a 90°C water bath for 90 minutes. Afterward, distilled water was added to dilute the volume to 25 mL, and the mixture was centrifuged at 3,000×g for 10 minutes. An appropriate amount of the supernatant was taken, and the supernatant was purified using a solid phase extraction cartridge (Oasis Max SPE cartridge, Waters, Milford, MA, USA) containing a mixed mode adsorbent for anion-exchange and acidic reverse phase, and this purified solution was used as the test solution.

[0057] For the HPLC column used for the separation of arsenic species for the analysis of inorganic arsenic (iAs), a Hamilton PRP X-100 (4.1 mm id × 250 mm L., 10 μm) was used at room temperature, and the mobile phase was set using a gradient elution method with (A) 3 mM ammonium nitrate (NH4NO3) containing 1% methanol (MeOH) and (B) 20 mM ammonium nitrate (NH4NO3) and 20 mM ammonium phosphate ((NH4)3PO4) containing 1% MeOH. The detection of arsenic chemical species, such as inorganic arsenic, was confirmed at 75 m / z of arsenic, and the spectral interference of ArCl and CalCl, which are representative substances matching the isotopic mass of arsenic, was minimized by removing the influence of matrix-based multiatomic interference caused by the collision reaction cell (CRC) of the Octopole Reaction System (ORS4) using helium (He) gas (Fig. 2). The analytical standard substances for arsenic chemical species were the inorganic arsenic species trivalent arsenic (AsⅢ) and pentavalent arsenic (AsⅤ), specifically sodium meta-arsenite (NaAsO2, 99.0% purity) and sodium arsenate dibasic heptahydrate (Na₂HAsO₄·7H₂O, 99.9% purity), purchased from Sigma-Aldrich (St. Louis, MO, USA); the organic arsenic species dimethylarsinic acid (DMA, (CH₃)₂AsO(OH), 98% purity) was purchased from Strem Chemicals (West Chester, PA, USA), and disodium methyl arsonate hexahydrate (MMA, (CH₃)AsNa₂O₃·6H₂O, 99.0% purity) was Supelco (Bellefonte, PA, USA), acenobetaine (asB, ((CH3)3As) + CH2COO -, 95% purity) and acenocholine bromide (AsC, (CH3)3As + CH2CH2OHㆍBr - , 95%) was purchased from Wako Pure Chemical Industries (Osaka, Japan) and used in this experiment.

[0058] As a result of LC-ICP-MS analysis performed after diluting and dissolving a mixed standard of arsenic chemical species in a 1% nitric acid solution (HNO3) and a 50% methanol (MeOH) extraction solvent and treating it using the same pretreatment method as the test substance, six arsenic chemical species were detected sequentially in the order of AsC, AsB, AsⅢ, DMA, MMA, and AsⅤ. The validation results showed that the correlation coefficient (R²) of the standard calibration curve 2 The linearity was found to be excellent with a value of 0.999 or higher (Fig. 3), and the recovery rates of AsⅢ, AsⅤ, AsB, AsC, DMA, and MMA were confirmed to be 92.6%, 90.5%, 103.6%, 94.8%, 97.7%, and 106.8%, respectively. As a result of confirming precision through three repetitions, the relative standard deviation (%RSD) was confirmed to be 2.11-3.37%. In addition, the reliability of the inorganic arsenic analysis results for the seaweed *Hijiki* was secured by confirming accuracy through a comparison of the certified value and recovery rate after analyzing the samples in the same manner as the samples using the certified reference material for inorganic arsenic in *Hijiki* (SRM 1568b, NIST, Gaithersburg, MD, USA) (Table 3).

[0059] [Table 3]

[0060]

[0062] In this example, the results of the arsenic chemical analysis of the seaweed *Hijiki* using the previously established HPLC-ICP / MS confirmed that As(V) accounted for the majority of the inorganic arsenic (Fig. 4), and the inorganic arsenic content of *Hijiki* was found to be in the range of 64.05-89.34 mg / kg dry weight with an average of 73.54±13.78 mg / kg dry weight (Table 4).

[0063] [Table 4]

[0064]

[0066] Example 2. Establishment of optimal conditions for arsenic removal from raw seaweed (Hijiki).

[0067] <Comparative Example 2-1> Removal of arsenic from seaweed *Hijiki* by heat treatment methods under various temperature conditions

[0068] This experiment was conducted to examine and verify the arsenic reduction efficiency by heat treatment. Dried sea tangle was soaked in tap water at a weight ratio of 1:40 (w / w) for 10 minutes, washed with running tap water, and then centrifugally dehydrated to remove foreign substances and salt in the first stage. The washed sea tangle was immersed in tap water at a weight ratio of 1:40 (w / w) for each temperature condition, which was maintained at a constant temperature beforehand, and heat-treated for 30 minutes. Afterward, it was washed with running tap water, centrifugally dehydrated, and then hot-air dried at 50°C. During this experiment, the temperatures of each tap water were set to 40, 60, 80, and 95°C. During the experiment, the arsenic reduction behavior (decrease kinetics) over time was checked at 5-minute intervals for each heat treatment temperature, and the arsenic removal rates for each heat treatment temperature were compared (Fig. 5).

[0069] As a result of examining the arsenic reduction behavior (decrease kinetics) over time according to the heat treatment temperature of the seaweed *Hijiki*, it was confirmed that both total arsenic and inorganic arsenic tended to decrease with heat treatment time under constant temperature conditions, and in particular, as the heat treatment temperature increased, the content of total arsenic and inorganic arsenic decreased relatively faster within a short period of time (Fig. 6).

[0070] As a result of reducing total arsenic in the seaweed *Hijiki* after heat treatment for 30 minutes at each temperature, total arsenic and inorganic arsenic were found to be 92.01 and 36.81 mg / kg dw, respectively, at 40℃, with removal rates of 46.54% and 58.80% compared to the untreated (raw material). At 95℃, total arsenic and inorganic arsenic were 24.67 and 5.06 mg / kg dw, with removal rates of 85.66% and 94.36%, respectively, confirming that the arsenic removal efficiency of the seaweed *Hijiki* increases with higher heat treatment temperatures. Additionally, it was observed that the ratio of inorganic arsenic to total arsenic decreased with higher heat treatment temperatures, indicating that the relatively toxic inorganic arsenic showed a relatively high removal effect upon heat treatment (Fig. 7 and Table 5).

[0071] [Table 5]

[0072]

[0074] As a result of this experiment, it was confirmed that while arsenic in the seaweed *Hijiki* can be effectively removed by heat treatment, changes in the external appearance (loss) and tissue destruction of the raw seaweed due to heat treatment were observed. Furthermore, the possibility of loss of effective substances in seaweed, such as functional polysaccharides like fucoidan, was raised, and it was determined that measures to overcome this need to be devised.

[0076] <Comparative Example 2-2> Removal of total arsenic and inorganic arsenic from raw seaweed (Hijiki) by acid treatment

[0077] The efficiency of arsenic reduction in seaweed by treatment with inorganic and organic acids was examined.

[0078] As a method for removing arsenic from the seaweed *Hijiki* by acid treatment, two types of inorganic acids, hydrochloric acid (HCl) and nitric acid (HNO3), and four types of organic acids, citric acid, malic acid, tartaric acid, and oxalic acid, were each prepared as acidic solutions at a level of 0.001-1% (w / v). This experiment was conducted under the same conditions as <Comparative Example 2-1>, in which dried sea tangle was soaked in tap water at a weight ratio of 1:40 (w / w) for 10 minutes, washed with running tap water, and centrifugally dehydrated to remove foreign substances and salts in the first wash, then immersed in acidic solutions prepared at different concentrations at a ratio of 1:40 (w / w) relative to the weight of the washed sea tangle, heat-treated at 95°C for 30 minutes, washed with running tap water, centrifugally dehydrated, and then hot-air dried at 50°C (Fig. 8).

[0079] As a result of analyzing the degree of arsenic reduction in the seaweed *Hijiki* by acid treatment, it was found that the arsenic reduction rate varied depending on the type of acid and its respective concentration, and generally, the arsenic reduction rate was relatively higher with organic acids than with inorganic acids. When confirming arsenic reduction according to each individual acid treatment condition, the removal rates for total arsenic and inorganic arsenic at a concentration of 0.001% (w / v) for hydrochloric acid treatment were 77.93% and 87.32%, respectively, showing a relatively low reduction effect and being lower than the heat treatment method without acid treatment. In contrast, the maximum reduction effect was observed at a concentration of 0.01% (w / v) for malic acid treatment, with 85.8% for total arsenic and 95.30% for inorganic arsenic (Table 6 and Fig. 9).

[0080] [Table 6]

[0081]

[0083] Meanwhile, heat treatment (hot water extraction) and acid treatment are common food processing methods primarily used for extraction purposes; however, they involve high energy consumption due to heating and cause the destruction or alteration of useful components. In particular, they harbor inherent food safety issues, such as the harmfulness of residues resulting from inorganic acid treatment, thus necessitating the development of alternatives to overcome these challenges.

[0085] <Example 2-3> Removal of total arsenic and inorganic arsenic from raw seaweed (Hijiki) under ultra-high pressure non-heating treatment conditions

[0087] Although the arsenic reduction (removal) effect of heat treatment and acid treatment of the seaweed *Hijiki* in <Comparative Example 2-1> and <Comparative Example 2-2> was confirmed, the efficiency of arsenic reduction (removal) of seaweed by ultra-high pressure non-heat treatment was examined as a method to compensate for disadvantages such as changes in the physical properties of the raw material and loss of active ingredients depending on the heating conditions. In the case of the acid used in this example, malic acid was used, which has the highest removal rate among the acids used in <Comparative Example 2-2>, and is a food additive registered and permitted for use in the 2022 Ministry of Food and Drug Safety “Standards and Specifications for Food Additives” and has proven safety without the need to set an Acceptable Daily Intake (ADI).

[0088] As a detailed method for the ultra-high pressure non-thermal treatment for arsenic reduction (removal) of the seaweed *Hijiki*, in the preparation stage, dried *Hijiki* was washed with running tap water and centrifugally dehydrated to remove foreign substances and salt in a first wash. Subsequently, the washed *Hijiki* was placed in a sealed container (e.g., a PET bottle) that facilitates pressure transmission, and malic acid solutions of 0-0.01% (wv) were added at a ratio of 1:40 (w / w) relative to the sample weight. After sealing the container, ultra-high pressure treatment was performed at room temperature under pressure conditions of 4,000 and 5,000 bar using a 50 L batch-type ultra-high pressure device (IWPM-600MPa-50L, Innoway, Seoul, Korea). During this process, in accordance with the high-pressure safety limit setting (safety mode) of the device, the ultra-high pressure treatment at 4,000 bar was performed continuously twice for 30 minutes per cycle (30 minutes / cycle × 2 cycles), totaling Ultra-high pressure treatment was performed for 60 minutes, and at 5,000 bar, ultra-high pressure treatment was performed for a total of 9 minutes under conditions of 3 consecutive cycles of 3 minutes each (3 minutes / cycle × 3 cycles), after which it was washed with running tap water, centrifugally dehydrated, and then hot-air dried at 50℃ (Fig. 10).

[0089] As a result of analyzing the degree of arsenic reduction in the seaweed *Hijiki* by ultra-high pressure non-heating treatment (Table 7 and Fig. 11), it was confirmed that the arsenic reduction rate was relatively high in both the ultra-high pressure treatment-01 condition (4,000 bar, 60 minutes) and the ultra-high pressure treatment-02 condition (5,000 bar, 9 minutes) under the 0.01% malic acid treatment condition (40 times the original material). The total arsenic and inorganic arsenic removal rates in the ultra-high pressure treatment-01 condition, which does not involve organic acid immersion, were 74.46% and 84.54%, respectively, while in the ultra-high pressure treatment-02 condition, they were 83.08% and 92.47%, respectively. This confirmed that the arsenic reduction (removal) rate in the seaweed *Hijiki* was higher in the ultra-high pressure treatment-02 method (5,000 bar, 9 minutes) than in the ultra-high pressure treatment-01 method (4,000 bar, 60 minutes).

[0090] [Table 7]

[0091]

[0093] In the ultra-high pressure non-heating experimental conditions treated with organic acid (malic acid), it was confirmed that the arsenic reduction (removal) efficiency of the seaweed *Hijiki* was highest, with total arsenic and inorganic arsenic removal rates of 86.50% and 95.50%, respectively, under the 0.01% malic acid treatment condition, similar to the acid treatment experimental conditions of <Comparative Example 2-2> conducted earlier, compared to the 0.1% malic acid treatment condition.

[0094] As a comprehensive result of the reduction of arsenic in the seaweed *Hijiki* through heat treatment (Comparative Example 2-1), acid treatment (Comparative Example 2-2), and ultra-high pressure non-heating (Example 2-3) of this example, it was summarized that under heat treatment conditions at 95°C for 30 minutes, a maximum of 85.66% of total arsenic and 94.34% of inorganic arsenic were removed; under acid treatment conditions with a concentration of 0.01% of the organic acid malic acid, a maximum of 85.95% of total arsenic and 95.30% of inorganic arsenic were removed; and under ultra-high pressure non-heating treatment conditions at 5,000 bar for 9 minutes, a maximum of 86.50% of total arsenic and 95.50% of inorganic arsenic were removed.

Claims

Claim 1 A method for reducing arsenic in Sargassum, comprising the step of immersing raw Sargassum in an aqueous solvent and pressurizing it under non-heating conditions, wherein the pressurizing treatment is performed at 3,000 bar to 6,000 bar. Claim 2 A method for reducing arsenic in Sargassum according to claim 1, wherein the Sargassum is one or more types selected from the group consisting of Sargassum fusiforme, Sargassum horneri, Sargassum serrations, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, Sargassum fusiforme, or Sargassum fusiforme. Claim 3 A method for reducing arsenic in Sargassum according to claim 1, wherein the weight ratio of the aqueous solvent to the total weight of the Sargassum raw material is 1:30 to 1:

60. Claim 4 A method for reducing arsenic in Sargassum according to claim 1, wherein the aqueous solvent comprises an organic acid. Claim 5 A method for reducing arsenic in Sargassum according to claim 4, wherein the organic acid is malic acid, citric acid, tartaric acid, oxalic acid, ascorbic acid, or gluconic acid. Claim 6 A method for reducing arsenic in Sargassum according to claim 4, wherein the organic acid in the aqueous solvent is 0.001% to 0.1% (w / v). Claim 7 delete Claim 8 A method for reducing arsenic in Sargassum according to claim 1, wherein the pressurization treatment is performed for 5 to 120 minutes in inverse proportion to the applied pressure.

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