Inulin chelated calcium compound with high degree of substitution and high calcium content, and preparation method therefor

Abstract

An inulin chelated calcium compound with a high degree of substitution and high calcium content, and a preparation method therefor. The compound is prepared from the following raw materials in parts by mass: 100 parts of inulin, 300-500 parts of isopropanol, 1-10 parts of an ionic liquid, 1-20 parts of urea, 55-75 parts of an alkalizing agent, 1-50 parts of water, 0.1-20 parts of a cross-linking agent, 60-180 parts of an etherifying agent, and 30-60 parts of calcium chloride. The prepared inulin chelated calcium has a high degree of substitution (DS≥1.5) and a high calcium content (up to 20%), has the advantages of high absorption, high bioavailability, strong universality, etc., and can meet the calcium supplementation requirements of various populations.

Description

A highly substituted, high-calcium inulin-chelated calcium compound and its preparation method Technical Field This invention belongs to the technical field of health functional food (pharmaceutical), and relates to a novel natural polymer modified calcium supplement, specifically to a high-substituted, high-calcium-content inulin chelated calcium compound and its preparation method. Background Technology Calcium is the most abundant mineral in the human body and is also an essential mineral, making up about 1-2% of body weight. Calcium plays a vital role in muscle contraction, blood clotting, and bone and teeth formation, and is crucial for maintaining healthy bones and teeth. However, dietary calcium intake is often insufficient to meet the body's needs, especially among the elderly, children, and pregnant women who are severely deficient in calcium. Therefore, additional calcium supplements are needed to maintain the body's calcium balance. Currently, calcium supplements on the market mainly include inorganic calcium, organic calcium, and amino acid chelated calcium. Inorganic calcium, such as calcium carbonate and calcium chloride, although high in calcium content, is not easily absorbed by the body and may cause gastrointestinal discomfort; therefore, it is not suitable for those with poor digestion. While organic calcium has a slightly higher absorption rate than inorganic calcium, it is still limited, and most require the assistance of vitamin D for absorption. Amino acid chelated calcium has high bioavailability and relatively good absorption, but it is not suitable for people with renal insufficiency or high blood calcium levels, as it can easily cause adverse side effects such as constipation, nausea, and vomiting. Therefore, there is still a need to develop high-purity natural chelated calcium to meet the needs of various population groups. Inulin is a natural functional edible polysaccharide, belonging to dietary fiber, which can improve intestinal function and is an internationally recognized intestinal prebiotic product. Inulin has excellent solubility and stability. Structurally, the hydroxyl groups on C-3, C-4 and C-6 of its furanose residues have etherification reaction ability, and can undergo bimolecular nucleophilic substitution reaction with etherifying agents in an alkaline environment to generate carboxymethyl inulin with carboxylic acid groups, and then prepare inulin chelated calcium through a chelation reaction with calcium ions. Wei Lingyun et al. synthesized inulin chelated calcium with a degree of substitution of 0.209 by this traditional method (Preparation and structural analysis of carboxymethyl inulin calcium [J]. Food Research and Development, 2011, 32(07): 8-11.). However, due to the low degree of substitution, the carboxymethyl inulin prepared by this method cannot efficiently chelate calcium ions, and the calcium content is low, which cannot achieve the real calcium supplementation effect. It cannot be used as a real calcium supplement, and its calcium supplementation effect cannot be further verified and applied. Therefore, how to prepare inulin chelated calcium compounds with high degree of substitution and high calcium content is a key technical challenge for the industrialization of inulin chelated calcium, and it is also an urgent need of the current consumer market. Summary of the Invention In view of the current state of technology, the purpose of this invention is to provide a highly versatile, bioavailable, and highly substituted inulin-chelated calcium with high calcium content; another purpose is to provide its preparation method. The objective of this invention is achieved by the following means: The highly substituted, high-calcium inulin chelated calcium is made from the following raw materials in parts by weight: 100 parts inulin, 300-500 parts isopropanol, 1-10 parts ionic liquid, 1-20 parts urea, 55-75 parts alkalizing agent, 1-50 parts water, 0.1-20 parts crosslinking agent, 60-170 parts etherifying agent, and 30-60 parts calcium chloride. Further optimization: 100 parts inulin, 300-400 parts isopropanol, 5-10 parts ionic liquid, 5-10 parts urea, 60-70 parts alkalizing agent, 5-50 parts water, 5-10 parts crosslinking agent, 90-130 parts etherifying agent, and 40-50 parts calcium chloride. The inulin is inulin or fructooligosaccharide; The ionic liquid is a quaternary ammonium salt ionic liquid, a phosphate ionic liquid, or an ether salt ionic liquid; The alkalizing agent is sodium hydroxide or potassium hydroxide; The etherifying agent is monochloroacetic acid or sodium monochloroacetate; The crosslinking agent is sodium tetraborate, 1,2-epoxypropylene, or epichlorohydrin. It is prepared by the following method: (1) Put inulin and isopropanol into a three-necked reactor equipped with a reflux condenser and a stirring device; An alkalizing agent, water, urea, a crosslinking agent, and an ionic liquid are added to the reactor, and a crosslinking alkalization reaction is carried out under heating conditions; then an etherifying agent is added to the reaction flask in batches, and the temperature is increased in stages for the reaction. (2) Transfer the material in the reactor to a material tank equipped with a nanofiltration membrane device to remove impurities; The filtrate is mixed and stirred with calcium chloride; after the reaction is complete, the material is transferred to a vacuum filtration flask or separator, and a clear filtrate is obtained by vacuum filtration or centrifugation; after spray drying or baking and pulverization, inulin chelated calcium with high substitution degree and high calcium content is obtained. In the application of promoting calcium absorption, the inulin chelated calcium prepared by this invention was compared with commercially available inorganic calcium and amino acid chelated calcium in animal experiments (ethics approval number: HNSD-2023BS0805). Experimental Methods: An animal experimental system for promoting calcium absorption using inulin-chelated calcium ([Ca]Syn) was established. The safety and calcium absorption-promoting efficacy of [Ca]Syn were evaluated from the perspectives of blood calcium regulation, bone calcium deposition, overall calcium absorption rate and metabolic rate, and induction of calcium absorption channels. The specific methods included the following: (1) Effect of [Ca]Syn on plasma calcium content in mice; (2) Effects of [Ca]Syn on femoral structure and calcium content in mice; (3) Effects of [Ca]Syn on calcium metabolism in mice; (4) Effect of [Ca]Syn on the expression of calcium ion channel protein in mouse duodenum. The results showed that: 1. The inulin chelated calcium prepared in this invention could restore the blood calcium concentration of calcium-deficient mice to normal levels within two weeks (see Table 1 and Figure 1); 2. The inulin chelated calcium prepared in this invention had a good effect on promoting bone calcium deposition and had a significant growth-promoting effect on damaged femoral tissue (see Table 2 and Figure 2); 3. The calcium absorption rate and calcium retention rate of the inulin chelated calcium prepared in this invention were higher than those of aspartic acid chelated calcium, and it could induce an increase in the expression of duodenal calcium ion channel proteins (see Figure 3 and Figure 4).

[0015] This invention utilizes ionic liquids and urea to disrupt the surface structure of inulin molecules, improving the efficiency and uniformity of the etherification reaction. This significantly increases the degree of substitution and anionic charge density of the intermediate carboxymethyl inulin, enabling it to efficiently chelate with calcium ions, thus producing a novel calcium supplement with high calcium content and easy absorption by the human body. Because inulin is used as a carrier, calcium ions are targeted and slowly released into the intestines for efficient absorption, thereby improving the absorption rate. Since the human stomach lacks enzymes to hydrolyze inulin, inulin-chelated calcium is not digested and absorbed in the stomach. It can enter the intestines intact and be preferentially utilized by probiotics, releasing calcium ions and short-chain fatty acids. Short-chain fatty acids promote the proliferation of colonic epithelial cells and lower intestinal pH, which is beneficial for calcium absorption, resulting in efficient calcium supplementation. Furthermore, because inulin has a bidirectional micro-regulatory effect on blood sugar—lowering blood sugar in diabetic patients and raising blood sugar when it is low—inulin-chelated calcium is also very suitable for diabetic patients with calcium deficiency. The inulin chelated calcium of this invention, as a calcium supplement, has the advantages of high absorption, high calcium content, high bioavailability, and wide applicability, and can meet the calcium supplementation needs of various groups. Furthermore, inulin itself has benefits such as improving gut microbiota and enhancing immunity. Therefore, the inulin chelated calcium of this invention not only provides a high-quality source of calcium but also promotes gut health. Animal experiments have shown excellent results, with calcium supplementation effects superior to commercially available inorganic and organic calcium, as well as aspartic acid chelated calcium. It overcomes the shortcomings of inorganic and organic calcium and can serve as a safe and efficient new calcium supplement. Compared with the prior art, the advantages of the present invention are as follows: 1. The inulin chelated calcium supplement prepared by this invention breaks through the traditional process and has a high degree of substitution (DS≥). It has a high calcium content (up to 20%) and is safe, making it superior to currently available calcium supplements. 2. The inulin chelated calcium supplement prepared by this invention has good solubility, easy absorption, and bioavailability. It has advantages such as high cost and wide applicability. 3. The inulin chelated calcium supplement prepared in this invention can rapidly restore blood calcium concentration to normal levels after administration. Normal level. 4. The inulin-chelated calcium supplement prepared in this invention has a good effect on promoting bone calcium deposition and is beneficial for bone health. Injured femoral tissue has a significant growth-promoting effect. 5. The inulin chelated calcium supplement prepared in this invention has a higher calcium absorption rate and calcium retention rate than [previous methods]. Aspartic acid chelates calcium and can induce an increase in the expression of duodenal calcium ion channel proteins. Attached Figure Description Figure 1 shows a comparison of the effects of different chelated calcium on plasma calcium levels in mice. Figure 2 shows a comparison of the three-dimensional structural changes of the femur in mice that have been administered different chelated calcium using microCT. Figure 3 shows the immunoblot of TRPV6 protein in mice administered different chelated calcium. Figure 4 shows the comparison of relative TRPV6 expression levels in mice given different chelated calcium solutions; Figure 5 shows a comparison of blood calcium and bone calcium levels in aged mice that received different chelated calcium supplements. Figure 6 shows a comparison of bone metabolism levels in aged mice treated with different chelated calcium. Detailed Implementation To better illustrate the present invention, the following examples are provided. Unless otherwise specified, all percentage contents are by mass: Example 1: The highly substituted, high-calcium inulin-chelated calcium is made from the following raw materials in parts by weight: inulin 100 The ingredients are: 300 parts isopropanol, 2 parts ionic liquid, 2 parts urea, 55 parts alkalizing agent, 2 parts water, 0.5 parts crosslinking agent, 90 parts etherifying agent, and 30 parts calcium chloride. The inulin is inulin; The ionic liquid is a quaternary ammonium salt ionic liquid; the alkalizing agent is sodium hydroxide or potassium hydroxide. The etherifying agent is monochloroacetic acid; The crosslinking agent is sodium tetraborate. It is prepared by the following method: Inulin and isopropanol are added to a three-necked reactor equipped with a reflux condenser and a stirring device; sodium hydroxide, water, urea, sodium tetraborate and quaternary ammonium salt ionic liquid are added to the reactor, and a cross-linking alkalization reaction is carried out at 20-45°C for 15-60 minutes; monochloroacetic acid is added to the reaction flask in batches, the temperature is maintained at 30-45°C, and the temperature is gradually increased to 50-70°C over 60 minutes, and the reaction is carried out for 2-10 hours; the material in the reactor is transferred to a material tank equipped with a nanofiltration membrane to remove impurities; the filtrate is mixed with calcium chloride and stirred for 2-8 hours; after the reaction is completed, the material is transferred to a vacuum filtration flask or separator, and a clear filtrate is obtained by vacuum filtration or centrifugation; the high-substituted, high-calcium-content inulin chelated calcium is obtained by spray drying or baking and pulverization. The degree of substitution was determined to be 1.54 and the calcium content was 13.8% by complexometric titration and ICP-MS. Example 2: The highly substituted, high-calcium inulin-chelated calcium is made from the following raw materials in parts by weight: inulin 100 The ingredients are: 400 parts isopropanol, 5 parts ionic liquid, 10 parts urea, 60 parts alkalizing agent, 20 parts water, 10 parts crosslinking agent, 110 parts etherifying agent, and 50 parts calcium chloride. The inulin is inulin; The ionic liquid is a phosphate ionic liquid; the alkalizing agent is sodium hydroxide or potassium hydroxide. The etherifying agent is sodium monochloroacetate; The crosslinking agent is 1,2-propylene oxide. The preparation method is the same as in Example 1. The degree of substitution was determined to be 1.89 and the calcium content to be 15.7% by complexometric titration and ICP-MS. Example 3: The highly substituted, high-calcium inulin-chelated calcium is made from the following raw materials in parts by weight: inulin 100 The ingredients are: 500 parts isopropanol, 10 parts ionic liquid, 20 parts urea, 75 parts alkalizing agent, 50 parts water, 20 parts crosslinking agent, 130 parts etherifying agent, and 60 parts calcium chloride. The inulin is inulin; The ionic liquid is an ether salt ionic liquid; The alkalizing agent is sodium hydroxide or potassium hydroxide; The etherifying agent is sodium monochloroacetate; The crosslinking agent is epichlorohydrin. The preparation method is the same as in Example 1. The degree of substitution was determined to be 2.23 and the calcium content was 17.6% by complexometric titration and ICP-MS. Application Example 1: Effect of the inulin-chelated calcium of the present invention on plasma calcium content in mice Blood was collected from the inner canthus of the right eye of mice using a capillary method (0.5 mL). The blood was incubated at 37°C for 10 min, centrifuged at 3500 rpm for 10 min, and the supernatant was collected for later use. The MTB microplate method was used, following the instructions of the plasma calcium (Ca) content detection kit (C004-2-1, Nanjing Jiancheng Biotechnology Institute). The results were measured using a microplate reader (BioTek, SYNERGY H1, 610 nm) and analyzed using GraphPad Prism 9.0. (Control group: blank group; Model group: calcium deficiency model group; [Ca]Syn group: inulin chelated calcium group; [Ca]Asp group: amino acid chelated calcium group) The results are shown in Table 1 and Figure 1. The plasma calcium level in the calcium deficiency model group was significantly lower than that in the normal group (P < 0.0001); while the plasma calcium levels in the [Ca]Syn and [Ca]Asp groups were significantly higher than those in the calcium deficiency model group (P = 0.0022, P = 0.0075), and close to those in the normal group (P = 0.4595, P = 0.2051). These results indicate that both [Ca]Syn and [Ca]Asp are effective in restoring blood calcium levels in calcium-deficient mice, with [Ca]Syn showing better results than [Ca]Asp. Table 1. Plasma calcium content in mice (n=5) Application Example 2: MicroCT Method for Detecting Changes in the Three-Dimensional Structure of the Femur Mice were euthanized by cervical dislocation, and the right femur was harvested. After washing with PBS, it was fixed in 4% formaldehyde solution. After 24 hours, it was removed, rinsed off the formaldehyde, and stored in 70% ethanol. For microCT experiments, the femur was wrapped in a soft plastic pad and fixed on the scanning bed. A Bruker SkyScan 1276 scanner was used for layered scanning. After scanning, Bruker N-Recon software was used for image reconstruction. Bruker CT-Analysis software was used to analyze bone volume / tissue volume (BV / TV), trabecular number (Tb.N), average trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), cortical volume (Ct.V), and cortical thickness (Ct.Th), generating binarized images. Bruker Data Viewer software was used for 2D image construction, and Bruker CTVox software was used for 3D image construction from the binarized images. (Control group is blank, Model group is calcium deficiency model group, [Ca]Syn group is inulin chelated calcium group, [Ca]Asp group is amino acid chelated calcium group) The results are shown in Table 2 and Figure 2. In the normal group of mice, the trabeculae in the bone tissue were well-developed, numerous, and densely arranged. In the calcium-deficient model mice, the trabeculae in the bone tissue were severely lacking, and the cortical bone thickness was reduced. In the CaCl2 group of mice, the trabeculae and cortical bone thickness in the bone tissue were somewhat restored, but the trabeculae were still mainly less. In the [Ca]Syn and [Ca]Asp groups of mice, the trabeculae and cortical bone thickness in the bone tissue were significantly restored, especially the [Ca]Syn group of mice, which showed the best recovery of spongy bone (Figure 2A). The bone volume fraction (BV / TV), trabecular bone number (Tb.N), average trabecular bone thickness (Tb.Th), trabecular bone separation (Tb.Sp), cortical bone volume (Ct.V), and cortical bone thickness (Ct.Th) of the five groups of mice were statistically analyzed (Table 2). Compared with normal mice, the calcium deficiency model group showed highly significant decreases or increases in BV / TV (Figure 2, B), Tb.N (Figure 2, C), Tb.Th (Figure 2, D), Tb.Sp (Figure 2, E), Ct.V (Figure 2, F), and Ct.Th (Figure 2, G) (P < 0.0001, P < 0.0001, P < 0.0001, P < 0.0001, P < 0.0001, P = 0.0004). Compared with the calcium deficiency model group, the CaCl2 group showed significantly higher levels of BV / TV, Tb.N, Tb.Th, Tb.Sp, Ct.V, and Ct.Th. Th showed some recovery, but it was not significant (P = 0.5773, P = 0.3544, P = 0.1049, P = 0.0056, P = 0.1939, P = 0.2359). In the [Ca]Syn group mice, BV / TV, Tb.N, Tb.Th, Tb.Sp, Ct.V, and Ct.Th all showed significant recovery (P = 0.0112, P = 0.0005, P = 0.0). 014, P=0.0003, P=0.0019, P=0.0392), and the BV / TV, Tb.N, Tb.Th, Tb.Sp, Ct.V, and Ct.Th of mice in the [Ca]Asp group also showed varying degrees of recovery (P=0.0614, P=0.0271, P=0.0191, P=0.0154, P=0.0207, P=0.0528). The results show that inulin chelated calcium [Ca]Syn has a good effect on promoting trabecular bone reconstruction and increasing the thickness of the bone cortex, and can repair osteoporosis-related diseases or injuries to a certain extent. Table 2. Parameters of the trabecular and cortical bone in the distal femur (n=3) Application Example 3 Mice were euthanized by cervical dislocation, and a small amount of duodenum was placed in a 1.5 mL centrifuge tube and stored at -80°C. When needed, the duodenum was removed, thawed in an ice bath, weighed, and then lysed with ice-cold lysis buffer containing 1% PMSF and 1% phosphatase inhibitor (sample weight g: lysis buffer volume ml = 1:5). The duodenum was minced with scissors and homogenized using an ultrasonic cell disruptor (JY92-IIN, Ningbo Xinzhi Biotechnology Co., Ltd.). The homogenate was then placed on ice for 30 min to allow for complete lysis. The sample was then centrifuged at 12000 rpm for 5 min at 4°C. An appropriate amount of supernatant was collected, and the total protein concentration was determined using the BCA method (P0012, Shanghai Beyotime Biotechnology Co., Ltd.). The supernatant sample was then denatured by boiling with 5×SDS loading buffer. Prepare the gel (Yamei One-Step PAGE Gel Rapid Preparation Kit, PG112, Shanghai Yamei Biomedical Technology Co., Ltd.), load the sample, and perform electrophoresis on a PacUniversal (BIO-RAD) system (80V for the upper gel, then 120V until the bromophenol blue reaches the appropriate position). Transfer to a PVDF membrane (300mA, 1h). After completion, wash the PVDF membrane thoroughly three times (5min / wash) with TBST. Then, block the PVDF membrane with TBST containing 5% skim milk at room temperature (blocking the PVDF membrane for 1h). Incubate the PVDF membrane overnight at 4°C in TRPV6 primary antibody (3411-1-AP, Proteintech). Then wash the PVDF membrane thoroughly three times (5min / wash) with TBST to remove excess primary antibody. Next, the PVDF membrane was immersed in the secondary antibody (SA00001-2, Proteintech) incubation solution and incubated on a shaker at 37°C for 2 hours. After that, the PVDF membrane was thoroughly washed three times (5 min each time) with TBST. Finally, the membrane was developed and exposed by ECL method (638173, Millipore), and developed by chemiluminescence imaging system (AI600, General Electric Company). The expression level of the target protein was analyzed by ImageJ software. The results are shown in Figures 3 and 4. The expression of the duodenal calcium channel protein TRPV6 in the calcium-deficient model group was lower than that in the normal group (P = 0.0003); while the expression of TRPV6 in the [Ca]Syn and [Ca]Asp groups was higher than that in the calcium-deficient model group (P = 0.0002, P = 0.0013), and close to that in the normal group (P = 0.9784, P = 0.7793). This result supports the persistently high level of chelated calcium absorption. Application Example 4: 48h-LD50 of inulin-chelated calcium ([Ca]Syn) in mice First, inulin-chelated calcium ([Ca]Syn) and amino acid-chelated calcium ([Ca]Asp) were dissolved in deionized water, and the concentrations of their saturated solutions were determined. The results showed that the water solubility of [Ca]Syn was approximately 0.667 g / mL, and the water solubility of [Ca]Asp was approximately 0.3 g / mL. The determination of their solubility provides a strong reference for setting the gavage dosage and volume in mice. To simulate the clinical application of calcium chelators, 8-week-old, 20g Kunming mice were treated by gavage. The mice received deionized water daily, and the rearing temperature was 25±1℃. The rearing and treatment of the experimental mice adhered to ethical requirements and regulations for the safe management of experimental animals, and were approved by the Experimental Animal Ethics Committee of Henan Normal University (ethics approval number: HNSD-2023BS0805). This section first determined the lethal dose range of the calcium chelating agent through preliminary experiments, and then conducted acute toxicity tests with six equal-ratio doses between the maximum no-lethal dose (M0) and the minimum total lethal dose (M100) in the preliminary experiments. The 48h-LD50 of [Ca]Syn in Kunming mice was 67.661 g / kg, and the 48h-LD50 of [Ca]Asp in Kunming mice was 43.095 g / kg (Table 1). Previous literature has reported that the 48h-LD50 of CaCl2 in Kunming mice is 1.94 g / kg. The results showed that the inulin chelated calcium prepared in this invention had a higher median lethal dose (LC50) than the aspartic acid chelated calcium currently the most widely used on the market, and its safety profile was excellent. Application Example 5 A calcium supplementation regimen using inulin-chelated calcium (Inu-Ca) was established for osteoporosis in aged mice. This regimen was then used to investigate the effects of inulin-chelated calcium on bone calcium, serum calcium levels, and bone formation. The specific research included two aspects: 1. The effects of Inu-Ca on calcium absorption and bone deposition in aged osteoporotic mice; 2. The effects of Inu-Ca on bone metabolism in aged osteoporotic mice. The experiments were divided into 7 groups: sham surgery control group (Sham), oophorectomy control group (OVX), OVX + calcium carbonate (Wyeth Pharmaceuticals Co., Ltd., National Drug Approval Number H10950029) treatment group (OVX + CaCO3, calcium dose 0.02 g / kg), OVX + L-aspartate calcium treatment group (OVX + Asp-Ca, calcium dose 0.02 g / kg), OVX + low-dose inulin chelated calcium treatment group (OVX + Inu-Ca-L, calcium dose 0.10 g / kg), OVX + medium-dose inulin chelated calcium treatment group (OVX + Inu-Ca-M, calcium dose 0.02 g / kg), and OVX + high-dose inulin chelated calcium treatment group (OVX + Inu-Ca-H, calcium dose 0.04 g / kg). This study used 12-month-old female C57BL / 6 mice, purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. They were housed in an SPF-grade animal facility at 22±2℃ and 50±10% humidity, with a 12-hour diurnal cycle, and provided with free access to standard laboratory animal feed and water. All mice underwent a one-week acclimatization period before being used in this study. All animal experiments adhered to ethical requirements and laboratory animal safety management regulations, and were approved by the Animal Ethics Committee of Henan Normal University (Approval No.: 2024BS-1216). Efforts were made to minimize the number of experimental animals and improve animal welfare. In the sham surgery group, only the abdominal cavity was incised without removing the ovaries. All other mice underwent bilateral ovariectomy after anesthesia (intraperitoneal injection of 45 mg / kg sodium pentobarbital). Mice in each group were fed for 16 weeks to induce an osteoporosis model, followed by calcium supplementation. Mice in the five calcium treatment groups were administered calcium supplement dissolved in physiological saline daily via gavage. Before gavage, 1% 1,25-dihydroxyvitamin D3 was added to the calcium supplement. The two control groups received an equal volume of physiological saline. Treatment continued for 12 weeks. The results are analyzed below: 1. Effects of different calcium supplements on calcium absorption and bone calcium deposition in mice The serum calcium and bone calcium levels of mice in each group are shown in Figure 5. (Figure 5 shows serum calcium (A) and bone calcium (Figure 5)...) R of the standard curve in experiment C) 2As can be seen, the standard curve was usable. Compared with the Sham control group, the OVX control group showed a slight decrease in serum calcium levels (P > 0.05) and a highly significant decrease in bone calcium content (P < 0.0001), confirming that OVX mice had significant osteoporosis. Compared with the OVX control group, the OVX+CaCO3 treatment group showed a slight increase in both serum calcium (P > 0.05) and bone calcium (P > 0.05) content, but neither was significant. Compared with the OVX control group, the OVX+Asp-Ca treatment group showed a slight increase in serum calcium levels (P > 0.05) and a significant increase in bone calcium content (P < 0.05). Compared with the OVX control group, the OVX+Inu-Ca-L treatment group showed a significant increase in serum calcium levels. The OVX+Inu-Ca-M treatment group showed significantly increased serum calcium levels (P < 0.01) and bone calcium content (P < 0.001) compared to the OVX control group, and significantly increased serum calcium levels (P < 0.05) compared to the Sham control group. Similarly, the OVX+Inu-Ca-H treatment group showed significantly increased serum calcium levels (P < 0.001) and bone calcium content (P < 0.0001) compared to the OVX control group, and significantly increased serum calcium levels (P < 0.01) compared to the Sham control group, while bone calcium content remained similar (P > 0.05). These results indicate that Inu-Ca has better absorption, which promotes greater bone calcium deposition. 2. Bone metabolism The levels of P1NP, OC, and BALP in each group of mice are shown in Figure 6. From P1NP (Figure 6A), R0 of the standard curves for the OC (C in Figure 6) and BALP (E in Figure 6) experiments 2As can be seen, the constructed standard curve is usable. Compared with the Sham control group, the levels of P1NP (P < 0.001), OC (P < 0.01), and BALP (P < 0.01) in the OVX control group were significantly decreased, confirming a significant reduction in osteogenic development in OVX mice. Compared with the OVX control group, the levels of P1NP (P > 0.05), OC (P > 0.05), and BALP (P > 0.05) in the OVX+CaCO3 treatment group were slightly increased, but not significantly. Compared with the OVX control group, the levels of P1NP (P < 0.01), OC (P < 0.01), and BALP (P < 0.05) in the OVX+Asp-Ca treatment group were significantly increased. The levels of P1NP (P < 0.01), OC (P < 0.01), and BALP (P < 0.05) in the OVX+Inu-Ca-L treatment group were significantly increased. Compared with the control group, the levels of P1NP (P < 0.001), OC (P < 0.01), and BALP (P < 0.05) were significantly increased in the OVX+Inu-Ca-M treatment group compared with the OVX control group, and were slightly higher than those in the Sham control group. Compared with the OVX control group, the levels of P1NP (P < 0.0001), OC (P < 0.0001), and BALP (P < 0.001) in the OVX+Inu-Ca-H treatment group were also significantly increased, and the level of P1NP (P < 0.05) was significantly higher than that in the Sham control group. These results indicate that Inu-Ca can induce a greater osteogenic response, and enhanced bone formation is a significant characteristic of bone remodeling. This invention provides highly substituted, high-calcium inulin-chelated calcium, which can be widely used by people who need calcium supplementation, such as the elderly, adolescents, and pregnant women. It can be used as an adjunct treatment for osteoporosis, hyperkalemia, hypocalcemia, parathyroid disease, and various diseases caused by calcium deficiency. Its excellent solubility and stability make it suitable as a calcium supplement in various forms, such as solid beverages, oral liquids, and capsules. This invention is not limited to the above embodiments, and any obvious modifications or equivalent substitutions should be considered within the scope of protection of this invention. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of this invention, and these should also be considered within the scope of protection of this invention, without affecting the effectiveness and practicality of the invention.

Claims

1. Inulin-chelated calcium, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts inulin, 300-500 parts isopropanol, 1-10 parts ionic liquid, 1-20 parts urea, 55-75 parts alkalizing agent, 1-50 parts water, 0.1-20 parts crosslinking agent, 60-180 parts etherifying agent, and 30-60 parts calcium chloride. The inulin is inulin or fructooligosaccharide; The ionic liquid is a quaternary ammonium salt ionic liquid, a phosphate ionic liquid, or an ether salt ionic liquid. The alkalizing agent is sodium hydroxide or potassium hydroxide; The etherifying agent is monochloroacetic acid or sodium monochloroacetate; The crosslinking agent is sodium tetraborate, 1,2-epoxypropylene or epichlorohydrin; It is prepared by the following method: (1) Inulin and isopropanol were put into a three-necked reactor equipped with a reflux condenser and a stirring device; alkalizing agent, water, urea, crosslinking agent and ionic liquid were added to the reactor and the reaction was carried out under heating conditions; then etherifying agent was added to the reaction flask in batches and the temperature was increased in stages for the reaction. (2) Transfer the material in the reactor to a material tank equipped with a nanofiltration membrane device to remove impurities; mix and stir the filtrate with calcium chloride; after the reaction is completed, transfer the material to a vacuum filtration flask or separator, and obtain a clear filtrate by vacuum filtration or centrifugation; obtain inulin chelated calcium by spray drying or baking and pulverizing.

2. The inulin-chelated calcium as described in claim 1, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts inulin, 300-400 parts isopropanol, 5-10 parts ionic liquid, 5-10 parts urea, 60-70 parts alkalizing agent, 5-50 parts water, 5-10 parts crosslinking agent, 90-130 parts etherifying agent, and 40-50 parts calcium chloride.

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