A preparation method of low-sodium high-calcium dried shrimp powder and low-sodium high-calcium dried shrimp powder

Abstract

The application provides a preparation method of low-sodium high-calcium dried shrimp skin powder and the low-sodium high-calcium dried shrimp skin powder. The preparation method of the low-sodium high-calcium dried shrimp skin powder comprises the following steps: mixing raw dried shrimp skin with distilled water to form a shrimp skin mixture; treating the shrimp skin mixture by means of an intermittent probe ultrasonic auxiliary treatment technology, and replacing the water source at a regular time interval to obtain pretreated shrimp skin; crushing the pretreated shrimp skin into shrimp skin powder, and adding the shrimp skin powder into distilled water at a solid-liquid ratio of 1:3-1:6 to form an initial solution; adding hydrogen-type cation exchange resin into the initial solution at a solid-liquid ratio of 1:4-1:6 to form a treatment solution; adjusting the pH of the treatment solution to 4.0-5.0, and stirring for a first preset time interval; adjusting the pH of the treatment solution to 6.5-7.0, adding organic acid, and stirring for a second preset time interval to obtain a treated mixture; filtering out the hydrogen-type cation exchange resin in the treated mixture by screening, and then performing spray drying treatment on the mixture to obtain the low-sodium high-calcium dried shrimp skin powder.

Description

Technical Field

[0001] This application relates to the field of food processing technology, and in particular to a method for preparing low-sodium, high-calcium shrimp powder and the low-sodium, high-calcium shrimp powder itself. Background Technology

[0002] Dried shrimp, a seafood rich in protein, calcium, and trace elements, is widely used in food processing. However, its high sodium content makes it unsuitable for infants, young children, those on low-sodium diets, and people with high blood pressure. Conventional desalination processes, such as simple soaking or washing, have low sodium removal efficiency (typically ≤60%), and repeated washing leads to a calcium loss rate of 30-50%, severely reducing the nutritional value of dried shrimp. Furthermore, these traditional methods are time-consuming and water-intensive, failing to meet the requirements of high efficiency, energy saving, and environmental protection in industrial production.

[0003] In recent years, while some improved technologies (such as ion exchange or membrane separation) have increased sodium removal efficiency, they still face problems such as insufficient resin adsorption selectivity, competitive loss of calcium ions, or high equipment costs, making it difficult to achieve the goal of low sodium content while maintaining high calcium content. Therefore, there is an urgent need to develop an efficient, green, and industrially applicable preparation technology to produce low-sodium, high-calcium shrimp powder to meet the industrial production needs of infant complementary foods, fortified foods, and low-sodium health foods, while also considering process stability and economy. Summary of the Invention

[0004] In view of this, this application provides a method for preparing low-sodium, high-calcium shrimp powder and the low-sodium, high-calcium shrimp powder, for use in preparing low-sodium, high-calcium shrimp powder.

[0005] Specifically, this application is implemented through the following technical solution:

[0006] The first aspect of this application provides a method for preparing low-sodium, high-calcium shrimp powder, the method comprising:

[0007] Mix raw dried shrimp shells with distilled water to form a shrimp shell mixture;

[0008] The shrimp shell mixture was treated with intermittent probe ultrasonic-assisted treatment technology, and the water source was changed periodically during the treatment process to obtain pretreated shrimp shells.

[0009] The pretreated shrimp shells are crushed into shrimp shell powder, and the shrimp shell powder is added to distilled water at a solid-liquid ratio of 1:3 to 1:6 to form an initial solution; wherein the particle size of the shrimp shell powder is less than or equal to 1.0 mm.

[0010] The hydrogen-form cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:4 to 1:6 to form the treatment solution; wherein the particle size of the hydrogen-form cation exchange resin is greater than or equal to the particle size of the shrimp powder, and the particle size of the hydrogen-form cation exchange resin is 1.0 mm to 1.5 mm.

[0011] The pH value of the treatment solution is adjusted to 4.0-5.0, and the solution is stirred for a first preset time to carry out the first stage of desalination treatment; wherein, the first preset time is 15-30 min.

[0012] The pH value of the treatment solution is adjusted to 6.5-7.0, and a specified organic acid is added to the treatment solution. The solution is stirred for a second preset time to carry out the second stage of desalination treatment and obtain the treated mixture. The second preset time is 5-10 min.

[0013] The hydrogen-form cation exchange resin in the treated mixture is sieved out and filtered, and the sieved and filtered mixture is spray-dried to obtain low-sodium, high-calcium shrimp powder.

[0014] The second aspect of this application provides a low-sodium, high-calcium shrimp powder, which is prepared using the low-sodium, high-calcium shrimp powder preparation method described in any one of the first aspects of this application.

[0015] The method for preparing low-sodium, high-calcium shrimp shell powder and the low-sodium, high-calcium shrimp shell powder provided in this application achieve efficient desalination and high retention of nutrients by integrating advanced technologies such as intermittent probe ultrasonic-assisted treatment, staged adsorption with hydrogen-form cation exchange resin, and spray drying. First, raw dried shrimp shells are soaked in distilled water at 4℃~10℃ with a solid-liquid ratio of 1:5~1:8 to soften the shrimp shells and dissolve surface salts. Then, they are treated with 15~25kHz ultrasound in pulse mode (30 seconds of operation followed by 2~5 minutes of pause) for 20~40 minutes, with the distilled water being replaced during 2~5 pauses to promote salt diffusion and initially reduce sodium content. Further, the pretreated shrimp shells are ground to a particle size ≤1.0mm and mixed with distilled water at a ratio of 1:3~1:6 to form a suspension. Then, hydrogen-form cation exchange resin with a particle size of 1.0~1.5mm is added, with a solid-liquid ratio of 1:4~1:6, to obtain the treated solution. In the first stage of desalination, the pH of the treated solution is adjusted... Under a weakly acidic environment of 4.0~5.0, the solution is stirred at 50~100 rpm for 15~30 minutes to adsorb and treat Na+ in the solution using a hydrogen-form cation exchange resin. + In the first stage of desalination, the sodium removal rate reached 65%~75%, and at the same time, in a weakly acidic environment, the chelation of Ca by endogenous organic acids in shrimp shells was promoted. 2+This significantly reduces calcium loss. In the second stage of desalination, a 0.1 mol / L alkaline solution (each addition ≤ 0.5% of the total volume) is used to adjust the pH of the treatment solution to 6.5-7.0, followed by the addition of a specified organic acid. The solution is then stirred at 50-100 rpm for 5-10 minutes to further adsorb residual Na. + Combining the desalination processes of the previous two stages, the total sodium removal rate exceeds 90%, while the calcium retention rate remains above 80%. Finally, after separating the resin through a 1.0mm sieve, the filtrate is spray-dried to obtain low-sodium, high-calcium shrimp powder with uniform particle size and excellent flavor. This method of preparing shrimp powder is green and environmentally friendly, and the final product is low in sodium, rich in calcium, and has excellent taste and storage stability, making it suitable for industrial production of health foods and meeting consumers' demand for low-sodium, high-nutrient foods. Attached Figure Description

[0016] Figure 1 This is a flowchart of Example 1 of the preparation method of the low-sodium, high-calcium shrimp powder provided in this application. Detailed Implementation

[0017] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0018] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0019] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0020] The following specific embodiments are given to illustrate the technical solution of this application in detail.

[0021] Figure 1This is a flowchart of Example 1 of the preparation method for the low-sodium, high-calcium shrimp powder provided in this application. Please refer to... Figure 1 The method provided in this embodiment may include:

[0022] S101. Mix raw dried shrimp skin with distilled water to form a shrimp skin mixture.

[0023] In this step, the dried shrimp shells are soaked in distilled water for initial hydration and preliminary cleaning. This allows the dried and hardened shrimp shells to absorb water and soften, and initially dissolves the salt and soluble substances on the surface of the dried shrimp shells, making them easier for subsequent processing.

[0024] It should be noted that, in one possible implementation, the temperature of the distilled water is 4℃~10℃, and the raw dried shrimp skins are mixed with distilled water at a solid-liquid ratio of 1:5~1:8 to obtain the shrimp skin mixture.

[0025] S102. The shrimp shell mixture is treated with intermittent probe ultrasonic-assisted treatment technology, and the water source is changed periodically during the treatment process to obtain pretreated shrimp shells.

[0026] It should be noted that the intermittent probe ultrasonic-assisted treatment technology specifically involves using a metal probe directly immersed in the shrimp shell mixture to deliver high-intensity focused ultrasonic energy to the mixture. This pulsed operation breaks down the shrimp shell tissue, causing the salt in the shrimp shell to diffuse and dissolve into the distilled water. The metal probe is a slender conical or stepped shape with a small diameter at its tip. Furthermore, the pulsed operation mode refers to the ultrasonic energy breaking down the shrimp shell in a "work-pause" cycle; for example, "work" for 2 seconds, then "pause" for 3 seconds. One "work-pause" cycle is called a pulse cycle.

[0027] In this step, during the treatment of the shrimp shell mixture using intermittent probe ultrasonic-assisted processing technology, the water source needs to be changed continuously to improve the cleaning efficiency of the shrimp shells and achieve pretreatment of the shrimp shells to remove sodium. Finally, pretreated shrimp shells are obtained.

[0028] Furthermore, in one possible implementation, the processing parameters for intermittent probe ultrasound-assisted treatment are as follows: the ultrasonic frequency is 15~25kHz, and in the pulse working mode, one "work-pause" pulse cycle consists of a 2~5 minute pause every 30 seconds of work, with a total processing time of 20~40 minutes. Specifically, during this process, the pause time within 2~5 pulse cycles is selected for replacing the distilled water with fresh water. Finally, after the treatment is completed, the shrimp shells are filtered out from the shrimp shell mixture, and the filtered shrimp shells are drained to obtain pre-treated shrimp shells.

[0029] It should be noted that this process serves as a preliminary desalination step, removing 30-40% of the salt content from the shrimp shells. Calcium in shrimp shells mainly exists in the form of bound calcium, which is not easily lost when the shrimp shell tissue is intact.

[0030] S103. The pretreated shrimp shells are crushed into shrimp shell powder, and the shrimp shell powder is added to distilled water at a solid-liquid ratio of 1:3 to 1:6 to form an initial solution; wherein the particle size of the shrimp shell powder is less than or equal to 1.0 mm.

[0031] In this step, a grinder, pulverizer or other equipment can be used to pulverize the pretreated shrimp shells into shrimp shell powder with a particle size ≤1.0mm. Then, the shrimp shell powder and distilled water are weighed and mixed according to the weight ratio. The fine shrimp shell powder particles are evenly dispersed in the distilled water to form an initial solution.

[0032] It should be noted that, in actual implementation, the particle size of the shrimp powder and the solid-liquid ratio of the shrimp powder to distilled water are set according to actual needs, and are not limited in this application. For example, in one embodiment, the particle size of the shrimp powder is 0.8 mm, and 100 g of shrimp powder is mixed with 400 g of distilled water, with a solid-liquid ratio of 1:4.

[0033] S104. The hydrogen-form cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:4 to 1:6 to form the treatment solution; wherein the particle size of the hydrogen-form cation exchange resin is greater than or equal to the particle size of the shrimp powder, and the particle size of the hydrogen-form cation exchange resin is 1.0 mm to 1.5 mm.

[0034] It should be noted that, in one possible implementation, the hydrogen-type cation exchange resin is any of the following resins: IR120 H-type resin, Amberlite IR120-type resin, Dowex 50WX-8-type resin, and Purolite C100-type resin.

[0035] In this step, the initial solution prepared in step S103 is added to a stirred tank, and then hydrogen-form cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:4 to 1:6 to form a treatment solution. The hydrogen-form cation exchange resin selectively adsorbs cations in the solution (mainly Na+) through the process. + ).

[0036] It should be noted that the solid-liquid ratio in this step refers to the mass-to-volume ratio of the hydrogen-form cation exchange resin to the initial solution, where "solid" represents the mass of the hydrogen-form cation exchange resin and "liquid" represents the volume of the initial solution. For example, in one embodiment, the initial solution is obtained by mixing 100g of shrimp powder with 400ml of distilled water. Subsequently, 120g of hydrogen-form cation exchange resin is added to this initial solution. In this case, the "solid" in the resulting treated solution represents the mass of the hydrogen-form cation exchange resin (120g), and the "liquid" represents the volume of the initial solution (400ml). Therefore, the solid-liquid ratio in this treated solution is 120g:400ml, or 3:10. It should be noted that the hydrogen-form cation exchange resin is in a suspended state during the reaction, and its wet apparent volume (converted from wet apparent density) is for reference only and is not included in the "liquid" volume of the solid-liquid ratio. Furthermore, the wet apparent volume of hydrogen-form cation exchange resin can be directly converted to its wet apparent density. For example, if the wet apparent density of hydrogen-form cation exchange resin is 1.2 g / ml, and 120 g of hydrogen-form cation exchange resin is added, then the wet apparent volume corresponding to 120 g of hydrogen-form cation exchange resin is 100 ml.

[0037] Furthermore, the particle size of the hydrogen-form cation exchange resin is greater than or equal to that of the shrimp shell powder. Referring to the previous description, the particle size of the shrimp shell powder is less than or equal to 1 mm. In this step, the particle size of the added hydrogen-form cation exchange resin is selected to be 1.0 mm-1.5 mm. This distinguishes the shrimp shell powder from the hydrogen-form cation exchange resin by particle size, allowing for thorough separation of the shrimp shell powder and hydrogen-form cation exchange resin through subsequent physical sieving.

[0038] S105. Adjust the pH value of the treatment solution to 4.0-5.0 and stir for a first preset time to carry out the first stage of desalination treatment; wherein, the first preset time is 15-30 min.

[0039] In this step, the pH of the treatment solution is adjusted to 4.0-5.0. At this point, the treatment solution is in a weakly acidic environment, and the hydrogen-form cation exchange resin reacts with Na+. + The adsorption selectivity is improved by stirring the treatment solution, which can accelerate the adsorption of Na+ by the hydrogen-form cation exchange resin. + The adsorption rate is adjusted, and after stirring for a first preset time, the first stage of desalination of the treatment liquid is completed. Through this first stage of desalination, the sodium removal rate in shrimp shells can reach 65%~75%.

[0040] The first preset duration is set according to actual needs. In this embodiment, it is not limited. Optionally, the first preset duration is 15~30 minutes.

[0041] Furthermore, in this weakly acidic environment, the endogenous acids in the shrimp shells (endogenous organic acids contained within the shrimp shells, including lactic acid, citric acid, and succinic acid, etc.) will dissociate into anions. These anions can react with Ca2+ released from the shrimp shells in the treatment solution. 2+ They combine to form macromolecular chelates, effectively blocking Ca2+. 2+ The competitive adsorption between the sodium and hydrogen-type cation exchange resin ensures efficient sodium removal while maximizing the retention of calcium contained in the shrimp shell.

[0042] It should be noted that the specific method for adjusting the pH of the treatment solution to 4.0~5.0 in this step can be selected according to actual needs, and this application does not limit it. For example, in one embodiment, the pH can be adjusted to 4.0~5.0 by gradually adding food-grade citric acid solution (concentration such as 0.1mol / L) to the treatment solution; as another possible implementation, a 0.1mol / L citric acid solution is used, and the amount of citric acid solution added each time does not exceed 0.5% of the total volume of the treatment solution. For example, for 100L of treatment solution, only less than or equal to 0.5L of citric acid solution is added at a time.

[0043] As described above, it is understandable that adjusting the pH to 4.0-5.0 (a weakly acidic environment) increases the adsorption selectivity of the hydrogen-form cation exchange resin for Na. Under acidic conditions, some free Ca binds with organic acids, reducing the resin's adsorption competition for Ca, thus allowing it to be retained. In the first stage of desalination, the sodium removal rate from shrimp shells reaches 65%-75%.

[0044] S106. Adjust the pH value of the treatment solution to 6.5-7.0, add a specified organic acid to the treatment solution, and stir for a second preset time to carry out the second stage of desalination treatment to obtain the treated mixture; wherein, the second preset time is 5-10 min.

[0045] In this step, after completing the first stage of desalination, an alkaline substance is gradually added to the treatment solution to adjust the pH value of the treatment solution to 6.5~7.0. The added alkaline substance can be a 0.1mol / L sodium bicarbonate (NaHCO3) solution. During the gradient addition of the alkaline substance, the amount of alkaline solution added each time is controlled to not exceed 0.5% of the total volume of the treatment solution to avoid drastic fluctuations in the pH value of the treatment solution. For example, in one embodiment, for 100L of treatment solution, no more than 0.5L of sodium bicarbonate solution is added each time.

[0046] It should be noted that, under this near-neutral pH environment, the hydrogen-form cation exchange resin reacts with Na+. +The adsorption selectivity decreased slightly, but it could still effectively adsorb residual sodium ions while reducing the adsorption of calcium ions (Ca). 2+ The competitive adsorption of calcium ensures the calcium content in the shrimp shells.

[0047] Furthermore, a specified organic acid is added to the treatment solution, and the mixture is stirred for a second preset time. During this process, the added specified organic acid can further promote the dissociation of endogenous organic acids in the shrimp shells, as well as the reaction of the dissociated anions with free Ca in the treatment solution. 2+ Forming stable chelates and reducing Ca 2+ The competitive adsorption of hydrogen-form cation exchange resin improves the efficiency of the second-stage desalination. Furthermore, after adjusting the pH and adding organic acid, the treatment solution is stirred for a second preset time of 5-10 minutes. This stirring time is sufficient to allow the hydrogen-form cation exchange resin to react with residual Na+ in the treatment solution. + Sufficient contact was ensured, completing the second stage of desalination while also guaranteeing the proper interaction between the added organic acids and Ca. 2+ The chelation process is fully carried out.

[0048] In addition, during the second preset time of stirring the treatment liquid, the stirring speed can be controlled to ensure uniform mixing of the components in the treatment liquid while avoiding damage to the structure of the shrimp powder; for example, the stirring speed is generally controlled at 50~100 rpm, that is, stirring the treatment liquid 50~100 times per minute.

[0049] It should be noted that, in one possible implementation, the specified organic acid added is any one of the following organic acids: citric acid, oxalic acid, lactic acid, malic acid, and gluconic acid.

[0050] Referring to the previous description, organic acids act as calcium protectants. Adjusting the pH of the system to a neutral environment increases the amount of free Ca. However, the adsorption capacity of the hydrogen-form cation exchange resin for Ca also gradually increases with the increase of pH. Adding organic acids forms soluble complexes with Ca, reducing the adsorption rate of the resin for calcium and thus retaining it.

[0051] Furthermore, short-term contact is crucial; prolonged contact can lead to the resin adsorbing and removing Ca. Through this second-stage desalination treatment of the shrimp powder, the sodium removal rate is further improved, reaching over 90% overall, while the calcium retention rate in the shrimp powder is greater than or equal to 80%.

[0052] S107. The hydrogen-type cation exchange resin in the treated mixture is sieved and filtered out, and the sieved and filtered mixture is spray-dried to obtain low-sodium, high-calcium shrimp powder.

[0053] After the above steps, the treated mixture contains shrimp powder, hydrogen cation exchange resin, and a small amount of dissolved salt and other soluble substances. Therefore, in this step, it is necessary to separate the hydrogen cation exchange resin from the shrimp powder in the mixture to obtain a pure shrimp powder suspension, and then dry it to prepare low-sodium, high-calcium shrimp powder.

[0054] Specifically, referring to steps S103 and S104 above, the particle size of the shrimp powder is less than or equal to 1.0 mm, while the particle size of the hydrogen-form cation exchange resin is 1.0 to 1.5 mm. Therefore, there is a difference in particle size between the shrimp powder and the hydrogen-form cation exchange resin. Thus, in this step, a sieve with a pore size of 1.0 mm is used to sieve and filter the treated mixture. The shrimp powder with a particle size less than 1.0 mm passes through the sieve and returns to the filtrate, while the hydrogen-form cation exchange resin with a particle size of 1.0 to 1.5 mm is retained by the sieve, thereby removing the hydrogen-form cation exchange resin from the treated mixture.

[0055] Furthermore, the sieved and filtered mixture is sent to a spray drying device for spray drying. By atomizing the filtered mixture into fine droplets and allowing them to come into rapid contact with hot air, the moisture evaporates quickly, thus obtaining dry low-sodium, high-calcium shrimp powder.

[0056] Furthermore, to investigate the effects of hydrogen-form cation exchange resin particle size, pH of the treatment solution in the first-stage desalination process, stirring time in the first-stage desalination process, pH of the treatment solution in the second-stage desalination process, and stirring time in the second-stage desalination process on the sodium removal rate and calcium retention rate of shrimp shells, multiple experimental and control groups were set up in this embodiment for analysis and illustration:

[0057] It should be noted that the sodium content in the raw dried shrimp is (5.67±0.12) g / kg, and the calcium content is (15.20±0.15) g / kg.

[0058] Furthermore, in accordance with the national standard GB 5009.91-2017 "National Food Safety Standard - Determination of Sodium in Food", the sodium content in raw shrimp shells and prepared shrimp shell powder was determined using the national standard method flame atomic absorption spectrometry (FAAS). The sodium removal rate was calculated according to the following formula:

[0059] Sodium removal rate % = (Sodium content of shrimp powder - Sodium content of raw shrimp) / Sodium content of raw shrimp %

[0060] In addition, according to the national standard GB 5009.92-2016 "National Food Safety Standard - Determination of Calcium in Food", the calcium content in raw shrimp shells and prepared shrimp shell powder was determined by flame atomic absorption spectrometry (FAAS), a national standard method. The calcium loss rate was calculated according to the following formula:

[0061] Calcium loss rate % = (Calcium content of shrimp powder - Calcium content of raw shrimp) / Calcium content of raw shrimp

[0062] The specific experimental and control groups are given below:

[0063] Experimental Group 1:

[0064] Specifically, Table 1.1 shows the preparation conditions for the low-sodium, high-calcium shrimp powder in Experimental Group 1 of this application:

[0065] Table 1.1 Preparation conditions of low-sodium, high-calcium shrimp powder shown in Experimental Group 1

[0066] 0.9 mm 1:5 4.5 18 min 7.0 5min

[0067] Please refer to Table 1.1. In Experimental Group 1, the pretreated shrimp shells were crushed into shrimp shell powder with a particle size of 0.9 mm. The shrimp shell powder was added to distilled water at a solid-liquid ratio of 1:5 to form an initial solution. Hydrogen-form cation exchange resin (IR120 H-form resin, particle size 1.0~1.5 mm) was added to the initial solution at a solid-liquid ratio of 1:5 and mixed to obtain the treated solution. Then, 0.1 mol / L of acidic substance was added in a gradient to adjust the pH to 4.5, and the mixture was stirred for 18 minutes. The first stage of desalination was completed by adding 0.1 mol / L of alkaline substance in a gradient to adjust the pH of the treatment solution to 7.0. At the same time, 0.1-0.2% (w / v) citric acid was added to the treatment solution and stirred for 5 minutes to complete the second stage of desalination, resulting in a treated mixture. Finally, the hydrogen-form cation exchange resin in the treated mixture was sieved and filtered out, and the sieved and filtered mixture was spray-dried to obtain low-sodium, high-calcium shrimp powder. The sodium and calcium contents of the obtained low-sodium, high-calcium shrimp powder were detected and compared with the sodium and calcium contents of raw dried shrimp powder to obtain the sodium removal rate and calcium loss rate under the experimental conditions.

[0068] Furthermore, in Experimental Group 1 shown in Table 1.1, the sodium and calcium contents of the prepared low-sodium, high-calcium shrimp powder, as well as the sodium removal rate and calcium loss rate under the conditions of this experimental group, are shown in Table 1.2 below:

[0069] Table 1.2 Product indicators of shrimp powder prepared under experimental group one conditions

[0070] Calcium content and calcium loss rate (13.01±0.11) g / kg and (14.41±0.94)%

[0071] Please refer to Tables 1.1 and 1.2 simultaneously. It can be seen that the shrimp powder in Experimental Group 1 has a particle size of 0.9 mm, which is less than 1.0 mm. This not only facilitates physical sieving and separation from IR120 H-type resin (particle size 1.0~1.5 mm), but the smaller particle size also significantly increases the contact area between the shrimp powder and the solution, promoting the release of Na+ from the shrimp powder. + The leaching and IR120 H-type resin of Na + The adsorption efficiency was significantly improved, resulting in a higher sodium removal rate for the final shrimp powder. Furthermore, Table 1.2 shows that the shrimp powder prepared in Experimental Group 1 had a sodium content as low as (1.72±0.09) g / kg, a sodium removal rate as high as (69.66±1.07)%, a calcium content of (13.01±0.11) g / kg, and a calcium loss rate of only (14.41±0.94)%. The conditions in Experimental Group 1, achieved by optimizing the particle size (0.9 mm), solid-liquid ratio of 1:5, stirring at pH 4.5 for 18 min in the first stage, and stirring at pH 7.0 for 5 min in the second stage with the addition of 0.1~0.2% (w / v) citric acid, resulted in highly efficient sodium removal. + By removing excess sodium and preserving calcium, the prepared low-sodium, high-calcium shrimp powder is of excellent quality, has extremely high nutritional value, and is suitable for high-quality food applications.

[0072] Experimental Group 2:

[0073] Specifically, Table 2.1 shows the preparation conditions for the low-sodium, high-calcium shrimp powder in Experimental Group 1 of this application:

[0074] Table 2.1 Preparation conditions of low-sodium, high-calcium shrimp powder shown in Experimental Group 2

[0075] 0.9 mm 1:6 4.8 16 min 6.9 7min

[0076] Please refer to Table 2.1. In Experimental Group 2, the pretreated shrimp shells were crushed into shrimp shell powder with a particle size of 0.9 mm. The shrimp shell powder was added to distilled water at a solid-liquid ratio of 1:5 to form an initial solution. Hydrogen-form cation exchange resin (IR120 H-form resin, particle size 1.0~1.5 mm) was added to the initial solution at a solid-liquid ratio of 1:6 to obtain the treated solution. Then, 0.1 mol / L of acidic substance was added in a gradient to adjust the pH to 4.8, and the mixture was stirred for 16 minutes. The first stage of sodium removal was completed by adding 0.1 mol / L of alkaline substance in a gradient to adjust the pH of the treatment solution to 6.9. Then, 0.1-0.2% (w / v) citric acid was added and stirred for 7 minutes to obtain the treated mixture. Finally, the hydrogen-form cation exchange resin in the treated mixture was sieved and filtered out, and the sieved and filtered mixture was spray-dried to obtain low-sodium, high-calcium shrimp powder. The sodium and calcium content in the obtained low-sodium, high-calcium shrimp powder was detected and compared with the sodium and calcium content in the raw dried shrimp powder to obtain the sodium removal rate and calcium loss rate under the experimental conditions.

[0077] Furthermore, in Experimental Group 2 shown in Table 2.1, the sodium and calcium contents of the prepared low-sodium, high-calcium shrimp powder, as well as the sodium removal rate and calcium loss rate under the conditions of this experimental group, can be shown in Table 2.2 below:

[0078] Table 2.2 Product indicators of shrimp powder prepared under the conditions of Experimental Group 2

[0079] Calcium content and calcium loss rate (12.97±0.12) g / kg and (14.67±0.79)%

[0080] Please refer to Tables 2.1 and 2.2 simultaneously. It can be seen that the shrimp powder in Experimental Group 2 has a particle size of 0.9 mm, which is less than 1.0 mm. This not only facilitates physical sieving and separation from IR120 H-type resin (particle size 1.0~1.5 mm) but also significantly increases the contact area between the shrimp powder and the solution, promoting the release of Na+ from the shrimp powder. + The leaching and IR120 H-type resin of Na + The adsorption efficiency significantly improved the sodium removal rate of the final shrimp powder. Table 2.2 shows that the sodium content of the shrimp powder prepared in Experimental Group 2 was as low as (1.79±0.10) g / kg, the sodium removal rate was as high as (68.45±1.28)%, the calcium content reached (12.97±0.12) g / kg, and the calcium loss rate was only (14.67±0.79)%.

[0081] Compared to the conditions in Experimental Group 1, Experimental Group 2 used a higher solid-liquid ratio of 1:6 and a slightly higher first-stage pH of 4.8 (compared to 4.5 in Experimental Group 1), as well as a second-stage pH of 6.9 with stirring for 7 min (compared to pH 7.0 for 5 min in Experimental Group 1). This maintained a high sodium removal rate while further reducing calcium loss, demonstrating superior calcium retention. Furthermore, Experimental Group 2 achieved highly efficient sodium removal by optimizing the solid-liquid ratio (1:6), the first-stage pH of 4.8 with stirring for 16 min, and the second-stage pH of 6.9 with stirring for 7 min, along with the addition of 0.1–0.2% (w / v) citric acid. + With minimal calcium loss and removal of impurities, the prepared low-sodium, high-calcium shrimp powder is of excellent quality and nutritional properties, making it suitable for high-quality food applications.

[0082] Experimental Group 3:

[0083] Specifically, Table 3.1 shows the preparation conditions for the low-sodium, high-calcium shrimp powder in Experiment Group 3 of this application:

[0084] Table 3.1 Preparation conditions of low-sodium, high-calcium shrimp powder shown in Experimental Group 3

[0085] 1.0 mm 1:4 4.2 20 min 6.8 9min

[0086] Please refer to Table 3.1. In Experimental Group 3, the pretreated shrimp shells were crushed into shrimp shell powder with a particle size of 1.0 mm. The shrimp shell powder was added to distilled water at a solid-liquid ratio of 1:5 to form an initial solution. Hydrogen-form cation exchange resin (IR120 H-form resin, particle size 1.0~1.5 mm) was added to the initial solution at a solid-liquid ratio of 1:4 to obtain the treated solution. Then, 0.1 mol / L of acidic substance was added in a gradient to adjust the pH to 4.2, and the mixture was stirred for 20 minutes. The first stage of sodium removal was completed by adding 0.1 mol / L hydroxide solution in a gradient to adjust the pH of the treatment solution to 6.8. Then, 0.1-0.2% (w / v) citric acid was added and stirred for 9 minutes to obtain the treated mixture. Finally, the hydrogen-form cation exchange resin in the treated mixture was sieved and filtered out, and the sieved and filtered mixture was spray-dried to obtain low-sodium, high-calcium shrimp powder. The sodium and calcium content in the obtained low-sodium, high-calcium shrimp powder was detected and compared with the sodium and calcium content in the raw dried shrimp powder to obtain the sodium removal rate and calcium loss rate under the experimental conditions.

[0087] Furthermore, in Experimental Group 3 shown in Table 3.1, the sodium and calcium contents of the prepared low-sodium, high-calcium shrimp powder, as well as the sodium removal rate and calcium loss rate under the conditions of this experimental group, can be shown in Table 3.2 below:

[0088] Table 3.2 Product indicators of shrimp powder prepared under the three conditions in the experimental group

[0089] Calcium content and calcium loss rate (12.97±0.08) g / kg and (14.67±0.88)%

[0090] Please refer to Experimental Groups 1 through 3 above. It can be seen that the 0.9mm shrimp powder particle size in Experimental Groups 1 and 2 has a smaller impact on sodium removal rate compared to the 1.0mm particle size in Experimental Group 3. However, the 0.9mm particle size achieved a sodium removal rate of 69.66% (sodium content 1.72±0.09 g / kg) in Experimental Group 1, slightly better than the 69.14% (1.75±0.10 g / kg) in Experimental Group 3. In contrast, Experimental Group 2 (shrimp powder particle size 0.9mm) only achieved 68.45% (1.79±0.10 g / kg), indicating that particle size differences need to be analyzed in conjunction with other parameters. Furthermore, when the solid-liquid ratio of the treatment liquid is 1:4, the sodium removal rate of the prepared shrimp powder is 69.14%, better than the 68.45% at a solid-liquid ratio of 1:6 and the 69.66% at a solid-liquid ratio of 1:5, due to the higher sodium content. + Concentration, lower initial pH, and longer stirring time can enhance the adsorption efficiency of IR120 H-type resin, while a 1:6 solid-liquid ratio dilution of Na... + Lower concentrations resulted in the worst sodium removal efficiency; furthermore, the environment with a pH of 4.2 in the first stage of Experimental Group 3 was more conducive to the adsorption of Na by the IR120 H-type resin than the environments with a pH of 4.5 in the first stage of Experimental Group 1 and a pH of 4.8 in the first stage of Experimental Group 2. + The effect of stirring for 20 minutes was better than that of stirring for 18 minutes and 16 minutes. In addition, the pH value of the second stage in experimental group 2 and experimental group 3, combined with the addition of 0.1~0.2% (w / v) citric acid and stirring for 7~9 minutes, had a loss rate as low as 13.80%~14.55%, which was better than that of experimental group 1 (pH 7.0, 5 min, 14.50%).

[0091] In summary, the shrimp powder obtained from experimental group 1 had the highest calcium content (13.01±0.11 g / kg), but experimental group 3 showed the best balance between sodium removal and calcium retention, making it more suitable for preparing low-sodium, high-calcium shrimp powder. Therefore, the following preparation conditions can be selected: shrimp powder particle size of 0.9 mm, solid-liquid ratio of 1:4 to 1:5, pH value of 4.2 to 4.5 in the first stage, stirring for 18 to 20 min in the first stage, pH value of 6.8 to 6.9 in the second stage, and stirring for 7 to 9 min. This will result in a lower sodium removal rate and a lower calcium loss rate in the prepared low-sodium, high-calcium shrimp powder.

[0092] Furthermore, to verify the effect of the above preparation conditions on the quality of shrimp powder preparation, this application also provides some comparative groups, which are described below:

[0093] Comparison Group 1:

[0094] Specifically, Table 4.1 shows the preparation conditions for the low-sodium, high-calcium shrimp powder of Comparative Group 1 of this application:

[0095] Table 4.1 Preparation conditions of low-sodium, high-calcium shrimp powder shown in Comparative Group 1

[0096] 1.5 mm 1:4 4.6 15 min 6.9 8min

[0097] Please refer to Table 4.1. In control group 1, the pretreated shrimp shells were crushed into shrimp shell powder with a particle size of 1.5 mm. The shrimp shell powder was added to distilled water at a solid-liquid ratio of 1:5 to form an initial solution. Hydrogen-form cation exchange resin (IR120 H-form resin, particle size 1.0~1.5 mm) was added to the initial solution at a solid-liquid ratio of 1:4 to obtain the treated solution. Then, 0.1 mol / L of acidic substance was added in a gradient to adjust the pH to 4.6, and the mixture was stirred for 15 minutes. The first stage of sodium removal was completed by adding 0.1 mol / L hydroxide in a gradient to adjust the pH of the treatment solution to 6.9. Then, 0.1-0.2% (w / v) citric acid was added and stirred for 8 minutes to obtain the treated mixture. Finally, the hydrogen-form cation exchange resin in the treated mixture was sieved and filtered out, and the sieved and filtered mixture was spray-dried to obtain low-sodium, high-calcium shrimp powder. The sodium and calcium content in the obtained low-sodium, high-calcium shrimp powder were detected and compared with the sodium and calcium content in the raw dried shrimp powder to obtain the sodium removal rate and calcium loss rate under the experimental conditions.

[0098] Furthermore, in Comparative Group 1 shown in Table 4.1, the sodium and calcium contents of the prepared low-sodium, high-calcium shrimp powder, as well as the sodium removal rate and calcium loss rate under the conditions of this comparative group, can be shown in Table 4.2 below:

[0099] Table 4.2 Product indicators of shrimp powder prepared under the conditions of Group 1

[0100] Calcium content and calcium loss rate (13.67±0.15) g / kg and (10.07±1.12)%

[0101] Please refer to both Tables 4.1 and 4.2. It can be seen that the shrimp powder in Group 1 has a particle size of 1.5 mm, which is larger than 1.0 mm. This not only makes it difficult to separate from IR120 H-type resin of similar particle size using physical methods, but the larger particle size also reduces the contact area between the shrimp powder and the solution, limiting the Na content in the shrimp powder. + Dissolution and IR120 H-type resin for Na + The adsorption efficiency was reduced, significantly decreasing the sodium removal rate of the final shrimp powder.

[0102] Comparison Group 2:

[0103] Specifically, Table 5.1 shows the preparation conditions for the low-sodium, high-calcium shrimp powder of comparative group two in this application:

[0104] Table 5.1 Preparation conditions of low-sodium, high-calcium shrimp powder shown in Comparative Group 2

[0105] 1.0 mm 1:3 5.5 25 min 6.9 6min

[0106] Please refer to Table 5.1. In control group two, the pretreated shrimp shells were crushed into shrimp shell powder with a particle size of 1.0 mm. The shrimp shell powder was added to distilled water at a solid-liquid ratio of 1:5 to form an initial solution. Hydrogen-form cation exchange resin (IR120 H-form resin, particle size 1.0~1.5 mm) was added to the initial solution at a solid-liquid ratio of 1:3 to obtain the treated solution. Then, 0.1 mol / L of acidic substance was added in a gradient to adjust the pH to 5.5, and the mixture was stirred for 25 minutes. The first stage of sodium removal was completed by adding 0.1 mol / L hydroxide in a gradient to adjust the pH of the treatment solution to 6.9. Then, 0.1-0.2% (w / v) citric acid was added and stirred for 6 minutes to obtain the treated mixture. Finally, the hydrogen-form cation exchange resin in the treated mixture was sieved and filtered out, and the sieved and filtered mixture was spray-dried to obtain low-sodium, high-calcium shrimp powder. The sodium and calcium content in the obtained low-sodium, high-calcium shrimp powder were detected and compared with the sodium and calcium content in the raw dried shrimp powder to obtain the sodium removal rate and calcium loss rate under the experimental conditions.

[0107] Furthermore, in Comparative Group 2 shown in Table 5.1, the sodium and calcium contents of the prepared low-sodium, high-calcium shrimp powder, as well as the sodium removal rate and calcium loss rate under the conditions of this comparative group, can be shown in Table 5.2 below:

[0108] Table 5.2 Product indicators of shrimp powder prepared under the conditions of Group 2

[0109] Calcium content and calcium loss rate (10.32±0.21) g / kg and (32.11±1.54)%

[0110] Please refer to both Tables 5.1 and 5.2. It can be seen that the solid-liquid ratio of the treatment solution in Comparative Group 2 is 1:3, which is outside the range of 1:4 to 1:6, and the pH in the first stage is 5.5, which is outside the range of 4.0 to 5.0. The lower solid-liquid ratio limits the amount of Na in the shrimp powder. + Dissolution and pH 5.5 also reduced the IR120 H-type resin's resistance to Na. + The adsorption selectivity resulted in a sodium removal rate of only 54.32±2.89%, far lower than the 68.45~69.14% of experimental groups one to three; in addition, pH 5.5 weakened the chelation of Ca by citric acid. 2+ The effect of a solid-liquid ratio of 1:3 further exacerbated the Ca2+ effect. 2+ The loss of calcium resulted in a calcium loss rate of 32.11±1.54% in the control group, which was much higher than the 14.41~14.67% in experimental groups one to three.

[0111] Comparison Group 3:

[0112] Specifically, Table 6.1 shows the preparation conditions for the low-sodium, high-calcium shrimp powder in comparative group three of this application:

[0113] Table 6.1 Preparation conditions of low-sodium, high-calcium shrimp powder shown in Comparison Group 3

[0114] 1.0 mm 1:5 4.5 15 min 7.8 15min

[0115] Please refer to Table 6.1. In control group three, the pretreated shrimp shells were crushed into shrimp shell powder with a particle size of 1.0 mm. The shrimp shell powder was added to distilled water at a solid-liquid ratio of 1:5 to form an initial solution. Hydrogen-form cation exchange resin (IR120 H-form resin, particle size 1.0~1.5 mm) was added to the initial solution at a solid-liquid ratio of 1:5 and mixed to obtain the treated solution. Then, 0.1 mol / L of acidic substance was added in a gradient to adjust the pH to 4.5, and the mixture was stirred for 15 minutes. The first stage of sodium removal was completed by adding 0.1 mol / L hydroxide solution in a gradient to adjust the pH of the treatment solution to 7.8. Then, 0.1-0.2% (w / v) citric acid was added and stirred for 15 minutes to obtain the treated mixture. Finally, the hydrogen-form cation exchange resin in the treated mixture was sieved and filtered out, and the sieved and filtered mixture was spray-dried to obtain low-sodium, high-calcium shrimp powder. The sodium and calcium content in the obtained low-sodium, high-calcium shrimp powder were detected and compared with the sodium and calcium content in the raw dried shrimp powder to obtain the sodium removal rate and calcium loss rate under the experimental conditions.

[0116] Furthermore, in Comparative Group 3 shown in Table 6.1, the sodium and calcium contents of the prepared low-sodium, high-calcium shrimp powder, as well as the sodium removal rate and calcium loss rate under the conditions of this comparative group, can be shown in Table 6.2 below:

[0117] Table 6.2 Product indicators of shrimp powder prepared under the conditions of Group 3

[0118] Calcium content and calcium loss rate (7.32±0.25) g / kg and (51.84±1.77)%

[0119] Please refer to Tables 6.1 and 6.2 simultaneously. It can be seen that in comparison group three, the pH in the second stage was 7.8, which is outside the range of 6.5–7.0, and the preset duration was 15 min, which is outside the range of 5–10 min. The pH of 7.8 in the second stage reduced the effect of the IR120H resin on residual Na+. + The adsorption selectivity is limited, and prolonged stirring can also lead to Na... +The insufficient adsorption resulted in a sodium removal rate of only 62.08±1.47% in the control group, lower than the 68.45~69.14% of experimental groups one to three. Furthermore, pH 7.8 weakened the adsorption of 0.1~0.2% (w / v) citric acid and Ca... 2+ The chelation efficiency is reduced, and prolonged stirring also exacerbates the problem of Ca. 2+ The calcium loss rate in the control group was as high as 51.84±1.77%, far exceeding the 14.41~14.67% in experimental groups one to three.

[0120] Based on the above experimental groups 1 to 3 and control groups 1 to 3, it can be seen that when the shrimp powder particle size, the solid-liquid ratio of the treatment solution, the pH and the first preset time of the first stage, and the pH and the second preset time of the second stage are all within the preset range of the preparation method of low sodium and high calcium shrimp powder provided in this application, low sodium and high calcium shrimp powder with high sodium removal rate and low calcium loss rate can be prepared.

[0121] In summary, Table 7.1 shows the preparation conditions for each experimental group and the control group, and Table 7.2 shows the product indicators for each experimental group and the control group.

[0122] Table 7.1 Preparation conditions for each experimental group and control group

[0123] Shrimp powder particle size 0.9 mm 0.9 mm 1.0 mm 1.5 mm 1.0 mm 1.0 mm Treatment liquid-solid ratio 1:5 1:6 1:4 1:4 1:3 1:5 Phase 1 pH 4.5 4.8 4.2 4.6 5.5 4.5 First preset duration 18 min 16 min 20 min 15 min 25 min 15 min Second stage pH 7.0 6.9 6.8 6.9 6.9 7.8 Second preset duration 5min 7min 9min 8min 6min 15min

[0124] Table 7.2 Product Indicators for Each Experimental Group and Control Group

[0125] Sodium content (1.72±0.09) g / kg (1.79±0.10) g / kg (1.75±0.10) g / kg (2.83±0.08) g / kg (2.59±0.12) g / kg (2.15±0.12) g / kg Sodium removal rate （69.66±1.07）% （68.45±1.28）% （69.14±1.30）% （50.09±0.44）% （54.32±2.89）% （62.08±1.47）% Calcium content (13.01±0.11) g / kg (12.97±0.12) g / kg (12.97±0.08) g / kg (13.67±0.15) g / kg (10.32±0.21) g / kg (7.32±0.25) g / kg Calcium loss rate （14.41±0.94）% （14.67±0.79）% （14.67±0.88）% （10.07±1.12）% （32.11±1.54）% （51.84±1.77）%

[0126] Please refer to Tables 7.1 and 7.2. It can be seen that the experimental conditions specified in this application are: shrimp powder particle size ≤ 1.0 mm, solid-liquid ratio of treatment solution 1:4~1:6, pH of the first stage 4.0~5.0, first preset time 15~30 min, pH of the second stage 6.5~7.0, and second preset time 5~10 min. Under these experimental conditions, the sodium removal rate of shrimp powder can be significantly improved through the synergistic effect of each experimental condition, while effectively retaining the calcium content in the shrimp powder, which is conducive to the preparation of high-quality shrimp powder with low sodium and high calcium.

[0127] The synergistic effect of the experimental conditions specified in this application is explained below:

[0128] First, the experimental conditions specified in this application, where the shrimp powder particle size is ≤1.0 mm, can increase the contact area between the shrimp powder surface and the treatment liquid, promoting the absorption of Na+. + It dissolves rapidly from within the shrimp powder; simultaneously, the solid-liquid ratio of the treatment liquid is 1:4 to 1:6, which also helps to remove the Na from the shrimp powder. +The rapid dissolution from the shrimp powder provides ample liquid volume and can also reduce the sodium content in the solution. + The concentration of [specific concentration] enhances the effect of hydrogen-form cation exchange resin (IR120 H, particle size 1.0~1.5 mm) on Na+. + The adsorption driving force. It should be noted that the smaller particle size of the shrimp powder ensures that the Na... + The high efficiency of release in solution, coupled with the high solid-liquid ratio, enables the adsorption of Na by the hydrogen-form cation exchange resin. + Providing ample liquid space allows for the synergistic effect of both factors to optimize the Na+ concentration in the solution. + Exchange efficiency.

[0129] Second, the weakly acidic environment (pH 4.0-5.0) in the first stage of the experimental conditions specified in this application can promote the dissociation of endogenous acids in shrimp shells into anions, which then react with Ca... 2+ Forming stable chelates and reducing Ca 2+ It competes with hydrogen-form cation exchange resins for adsorption; simultaneously, a solid-liquid ratio of 1:4 to 1:6 ensures sufficient volume of the treatment solution to support the dissociation of endogenous acids and Na+. + Dissolved, while diluting Na + Concentration enhances resin adsorption selectivity. Under the synergistic effect of a first-stage pH of 4.0–5.0 and a solid-liquid ratio of 1:4–1:6, the internal Na+ concentration of shrimp shell powder can be optimized. + While releasing, it also protects the Ca in the shrimp powder. 2+ The content of.

[0130] Third, the experimental conditions specified in this application, with the pH limited to 4.0-5.0 in the first stage, can promote the dissolution of Na⁺ and Ca in the treatment solution. 2+ Chelation, with stirring time limited to 15-30 minutes to ensure Na + Fully release and contact with the resin, while avoiding excessive stirring to prevent Ca from forming. 2+ Chelate dissociation or non-specific adsorption of Ca by resin 2+ The stirring time of 15-30 min specified in the experimental conditions of this application, combined with the weakly acidic pH, can balance the effect of the hydrogen-form cation exchange resin on Na+ in the treatment solution. + Highly efficient adsorption and Ca in shrimp powder 2+ Protection.

[0131] Fourth, the pH of the first stage of the experimental conditions specified in this application is limited to 4.0~5.0, which can promote the absorption of Na+ by the shrimp powder in a weakly acidic environment. + Dissolves and forms Ca 2+ Chelates lay the foundation for efficient sodium removal and calcium protection; simultaneously, the second stage optimizes the resin's resistance to Na+ by maintaining a near-neutral environment with a pH of 6.5-7.0. +The adsorption selectivity of Ca, while maintaining the Ca adsorption selectivity. 2+ The stability of chelates reduces Ca 2+ Competitive adsorption with resin.

[0132] Fifth, the pH of the second stage in the experimental conditions specified in this application is limited to 6.5-7.0, which can be Na... + Provides a stable ion exchange environment, enhancing the hydrogen-form cation exchange resin's ability to exchange Na+. + The adsorption efficiency was optimized; meanwhile, the second preset stirring time was limited to 5-10 min to ensure Na adsorption efficiency. + Further adsorption, while reducing Ca 2+ The dissociation and loss of chelates prevent the non-specific adsorption of Ca by hydrogen-form cation exchange resins. 2+ Thus, the combination of a near-neutral pH of 6.5-7.0 in the second stage and a short stirring time of 5-10 minutes in the second preset duration can optimize the sodium removal selectivity and calcium retention of shrimp powder during the preparation process.

[0133] In summary, the shrimp powder preparation method provided in this application, with its shrimp powder particle size ≤1.0 mm, solid-liquid ratio of 1:4 to 1:6, first-stage pH 4.0 to 5.0, first preset time 15 to 30 min, second-stage pH 6.5 to 7.0, and second preset time 5 to 10 min, can significantly optimize the sodium removal efficiency and calcium retention in the shrimp powder preparation process, thereby producing high-quality shrimp powder with low sodium and high calcium content, meeting the production needs of high-quality food industrialization.

[0134] The method for preparing low-sodium, high-calcium shrimp shell powder provided in this embodiment integrates advanced technologies such as intermittent probe ultrasonic-assisted treatment, staged adsorption with hydrogen-form cation exchange resin, and spray drying to achieve efficient desalination and high retention of nutrients. First, raw dried shrimp shells are soaked in distilled water at 4℃~10℃ with a solid-liquid ratio of 1:5~1:8 to soften the shrimp shells and dissolve surface salts. Then, they are treated with 15~25kHz ultrasound in pulse mode (30 seconds of operation followed by 2~5 minutes of pause) for 20~40 minutes, with the distilled water being replaced during 2~5 pauses to promote salt diffusion and initially reduce sodium content. Further, the pretreated shrimp shells are ground to a particle size ≤1.0mm and mixed with distilled water at a ratio of 1:3~1:6 to form a suspension. Then, hydrogen-form cation exchange resin with a particle size of 1.0~1.5mm is added, with a solid-liquid ratio of 1:4~1:6, to obtain the treated solution. In the first stage of desalination, the pH of the treated solution is adjusted... Under a weakly acidic environment of 4.0~5.0, the solution is stirred at 50~100 rpm for 15~30 minutes to adsorb and treat Na+ in the solution using a hydrogen-form cation exchange resin. +In the first stage of desalination, the sodium removal rate reached 65%~75%, and at the same time, in a weakly acidic environment, the chelation of Ca by endogenous organic acids in shrimp shells was promoted. 2+ This significantly reduces calcium loss. In the second stage of desalination, a 0.1 mol / L alkaline solution (each addition ≤ 0.5% of the total volume) is used to adjust the pH of the treatment solution to 6.5-7.0, followed by the addition of a specified organic acid. The solution is then stirred at 50-100 rpm for 5-10 minutes to further adsorb residual Na. + Combining the desalination processes of the previous two stages, the total sodium removal rate exceeds 90%, while the calcium retention rate remains above 80%. Finally, after separating the resin through a 1.0mm sieve, the filtrate is spray-dried to obtain low-sodium, high-calcium shrimp powder with uniform particle size and excellent flavor. This method of preparing shrimp powder is green and environmentally friendly, and the final product is low in sodium, rich in calcium, and has excellent taste and storage stability, making it suitable for industrial production of health foods and meeting consumers' demand for low-sodium, high-nutrient foods.

[0135] The second aspect of this application also provides a low-sodium, high-calcium shrimp powder, which can be prepared using the low-sodium, high-calcium shrimp powder preparation method described in any of the above embodiments.

[0136] It should be noted that the sodium content of the low-sodium, high-calcium shrimp powder provided in this application is 1.63 g / kg to 1.89 g / kg, and the calcium content of the low-sodium, high-calcium shrimp powder is 12.85 g / kg to 13.12 g / kg.

[0137] The low-sodium, high-calcium dried shrimp powder provided in this application has a sodium content far lower than that of ordinary dried shrimp powder, which can effectively reduce sodium intake for infants and young children and people on low-sodium diets, and reduce health risks such as high blood pressure. Its high calcium content, which is close to or higher than that of ordinary dried shrimp powder, can significantly supplement the calcium needed by the human body and promote bone development. It is especially suitable for infants and young children and people with calcium deficiency. This low-sodium, high-calcium dried shrimp powder is suitable for preparing complementary foods for infants and young children, fortified foods and low-sodium health foods.

[0138] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing low-sodium, high-calcium shrimp powder, characterized in that, The preparation method includes: Mix raw dried shrimp shells with distilled water to form a shrimp shell mixture; The shrimp shell mixture was treated with intermittent probe ultrasonic-assisted treatment technology, and the water source was changed periodically during the treatment process to obtain pretreated shrimp shells. The pretreated shrimp shells are crushed into shrimp shell powder, and the shrimp shell powder is added to distilled water at a solid-liquid ratio of 1:3 to 1:6 to form an initial solution; wherein the particle size of the shrimp shell powder is less than or equal to 1.0 mm. An IR120 H-type hydrogen cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:4 to 1:6 to form a treatment solution; wherein the particle size of the IR120 H-type hydrogen cation exchange resin is larger than that of the shrimp powder, and the particle size of the IR120 H-type hydrogen cation exchange resin is 1.0 mm to 1.5 mm. The pH value of the treatment solution is adjusted to 4.0-5.0, and the solution is stirred for a first preset time to carry out the first stage of desalination treatment; wherein, the first preset time is 15-30 min. The pH of the treatment solution is adjusted to 6.5-7.0, citric acid is added to the treatment solution, and the mixture is stirred for a second preset time to carry out the second stage of desalination treatment, thereby obtaining the treated mixture; wherein, the second preset time is 5-10 min. The IR120 H-type hydrogen cation exchange resin in the treated mixture is sieved out and filtered, and the sieved and filtered mixture is spray-dried to obtain low-sodium, high-calcium shrimp powder.

2. The preparation method according to claim 1, characterized in that, The shrimp powder has a particle size of 0.9 mm; The IR120 H-type hydrogen cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:4 to 1:6 to form the treatment solution, comprising: The IR120 H-type hydrogen cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:

5. The step of adjusting the pH of the treatment solution to 4.0-5.0 and stirring for a first preset time to perform the first stage of desalination includes: The pH of the treatment solution was adjusted to 4.5 and stirred for 18 minutes. The step of adjusting the pH of the treatment solution to 6.5-7.0, adding citric acid to the treatment solution, and stirring for a second preset time includes: The pH of the treatment solution was adjusted to 7.0, and citric acid was added to the treatment solution and stirred for 5 minutes.

3. The preparation method according to claim 1, characterized in that, The shrimp powder has a particle size of 0.9 mm; The IR120 H-type hydrogen cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:4 to 1:6 to form the treatment solution, comprising: The IR120 H-type hydrogen cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:

6. The step of adjusting the pH of the treatment solution to 4.0-5.0 and stirring for a first preset time to perform the first stage of desalination includes: The pH of the treatment solution was adjusted to 4.8 and stirred for 16 minutes. The step of adjusting the pH of the treatment solution to 6.5-7.0, adding citric acid to the treatment solution, and stirring for a second preset time includes: The pH of the treatment solution was adjusted to 6.9, and citric acid was added to the treatment solution and stirred for 7 minutes.

4. The preparation method according to claim 1, characterized in that, The shrimp powder has a particle size of 1.0 mm; The process involves adding the IR120 H-type hydrogen cation exchange resin to the initial solution at a solid-liquid ratio of 1:4 to 1:6 to form the treatment solution, comprising: The IR120 H-type hydrogen cation exchange resin is added to the initial solution at a solid-liquid ratio of 1:

4. The step of adjusting the pH of the treatment solution to 4.0-5.0 and stirring for a first preset time to perform the first stage of desalination includes: The pH of the treatment solution was adjusted to 4.2 and stirred for 20 minutes. The step of adjusting the pH of the treatment solution to 6.5-7.0, adding citric acid to the treatment solution, and stirring for a second preset time includes: The pH of the treatment solution was adjusted to 6.8, and citric acid was added to the treatment solution, which was then stirred for 9 minutes.

5. The preparation method according to claim 1, characterized in that, The process of mixing raw dried shrimp shells with distilled water to obtain a shrimp shell mixture includes: Raw dried shrimp shells are mixed with distilled water at a solid-liquid ratio of 1:5 to 1:8 to obtain a shrimp shell mixture.

6. The preparation method according to claim 1 or 5, characterized in that, The process of treating the shrimp shell mixture using intermittent probe ultrasonic-assisted treatment technology, with periodic water source changes during the treatment process, to obtain pretreated shrimp shells includes: The shrimp shell mixture was treated with intermittent probe ultrasonic-assisted treatment technology; wherein the treatment parameters of intermittent probe ultrasonic-assisted treatment were: ultrasonic frequency of 15~25 kHz, treatment time of 20~40 min, and a pause of 2~5 min every 30 s. During the treatment process, change the distilled water 2-5 times; After processing, the shrimp skins are filtered out from the shrimp skin mixture and drained to obtain pre-treated shrimp skins.

7. A low-sodium, high-calcium shrimp powder, characterized in that, The low-sodium, high-calcium shrimp powder is prepared using the method described in any one of claims 1-6.

8. The low-sodium, high-calcium shrimp powder according to claim 7, characterized in that, The sodium content of the low-sodium, high-calcium shrimp powder is 1.63 g / kg to 1.89 g / kg, and the calcium content of the low-sodium, high-calcium shrimp powder is 12.85 g / kg to 13.12 g / kg.

Images