A powder calcium lactate and a method for preparing the same

Abstract

The application discloses a kind of powder calcium lactate and preparation method thereof, it is related to chemical pharmacy technical field, specifically belongs to patent classification C07C59 / 08.Its preparation method includes the following steps: a) with calcium carbonate and lactic acid reaction, prepare calcium lactate crystal;B) the calcium lactate crystal is dried and crushed, and the calcium lactate intermediate is obtained;C) in fluid bed, the calcium lactate intermediate is sequentially coated with three layers, then dry, namely obtained.The application can effectively solve hygroscopic caking, cover bitter taste, and can realize slow release of calcium ion by coating specific film layer on the surface of powder calcium lactate.

Description

Technical Field

[0001] This invention relates to the field of chemical pharmaceutical technology, belonging to patent classification number C07C59 / 08, specifically to a powdered calcium lactate and its preparation method. Background Technology

[0002] Calcium is an essential macroelement for the human body, playing a crucial role in physiological processes such as bone development, nerve regulation, and muscle function. Adequate calcium intake is especially important for rapidly growing infants and young children. Calcium lactate, as a common organic calcium supplement, is widely used in infant food and nutritional supplements due to its good water solubility, high bioavailability, and relatively low gastrointestinal irritation. However, existing powdered calcium lactate still has several problems in practical applications: Because powdered calcium lactate has a large specific surface area, it is highly hygroscopic, easily absorbing moisture from the air and clumping during storage or processing, affecting the product's flowability, dispersibility, and shelf life, and making it difficult to add evenly to food; furthermore, lactic acid... Calcium itself has a bitter taste, and in powder form, its bitter components are more easily contacted by taste buds, making the bitterness particularly pronounced. When used in infant food, this can severely affect palatability, causing infants to refuse to eat it and reducing the effectiveness of calcium supplementation. In addition, conventional powdered calcium lactate dissolves rapidly in the gastrointestinal tract after entering the body, releasing calcium ions. This leads to a sharp increase in the local calcium ion concentration in the gastrointestinal tract. For infants whose digestive systems are not yet fully developed, this high local concentration may irritate the gastrointestinal mucosa, causing discomfort such as bloating and diarrhea, affecting nutrient absorption and overall health. Therefore, there is an urgent need for a technical solution that can improve the hygroscopic and clumping properties of powdered calcium lactate, mask the bitterness, and achieve slow-release of calcium ions to enhance its applicability in food and other fields. Summary of the Invention

[0003] The purpose of this invention is to provide a powdered calcium lactate and its preparation method to solve the technical problems mentioned in the background. This invention, by coating the surface of the powdered calcium lactate with a specific film layer, effectively solves the problems of moisture absorption and clumping, masking bitterness, and also enables the slow release of calcium ions.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for preparing powdered calcium lactate includes the following steps:

[0006] a) Calcium lactate crystals are prepared by reacting calcium carbonate with lactic acid;

[0007] b) Dry and pulverize the calcium lactate crystals to obtain the calcium lactate intermediate;

[0008] c) The calcium lactate intermediate is coated in three layers in a fluidized bed and then dried to obtain the final product.

[0009] Preferably, in step a), the mass ratio of calcium carbonate to lactic acid is 1:2 to 3.

[0010] Preferably, in step b), the drying is performed by flash drying at 80–120°C or by forced air drying until the moisture content is ≤1.5 wt%.

[0011] Preferably, in step c), the three coating layers are:

[0012] Inner coating: Spray a coating solution composed of caprylic / capric triglyceride, malic acid and zinc acetate to cause the malic acid to undergo in-situ esterification with the hydroxyl groups on the surface of calcium lactate to form a hydrophobic inner layer;

[0013] Intermediate coating: A coating solution composed of chitosan oligosaccharide and calcium chloride aqueous solution is sprayed on, so that chitosan oligosaccharide and calcium ions are coordinated and cross-linked to form a controlled-release intermediate layer;

[0014] Outer coating: A coating solution composed of ethanol solution of zein, glycerol, triethyl citrate and propyl gallate is sprayed on, and an elastic outer layer is formed by free radical cross-linking initiated by propyl gallate.

[0015] In this invention, the calcium lactate intermediate undergoes a three-layer coating process. First, the inner coating uses caprylic / capric triglyceride as the continuous lipid phase, malic acid as the crosslinking monomer, and zinc acetate as the catalyst. Under the catalysis of zinc acetate, malic acid partially esterifies with the hydroxyl groups on the surface of calcium lactate, forming a "point-anchor" covalent bond. When the environment is acidic, the ester bond reversibly breaks, facilitating localized release from the gastrointestinal tract. Caprylic / capric triglyceride is a low-polarity medium-chain fatty acid; after film formation, it forms a hydrophobic barrier, and the hydrophobic layer shields against the calcium lactate. 2+ Direct contact with the taste buds prevents the bitter taste of calcium lactate from lingering in the mouth. The middle coating utilizes the -NH2 on the chitosan oligosaccharide to react with Ca... 2+ Coordination bonds are formed to create a film, and the swollen chitosan provides a sustained-release effect. The outer coating, zein, is cross-linked with propyl gallate to form a plant-based elastomer membrane, effectively buffering friction and collisions during transport, reducing membrane damage, and providing dual protection against oxygen and moisture. This, combined with the hydrophobic inner coating, prevents calcium lactate from absorbing moisture and clumping. Figure 1 The image shows a SEM image of the powdered calcium lactate particles prepared according to the present invention. It can be observed from the image that the calcium lactate has a granular structure and a smooth and uniform surface.

[0016] Preferably, the weight ratio of caprylic / capric triglyceride, malic acid, and zinc acetate in the inner coating is 90:10-15:0.5-2.

[0017] Preferably, modified calcium chloride is added to the coating solution in the inner coating layer.

[0018] Preferably, the modified calcium chloride is prepared by hydrophobic modification of the surface of calcium chloride particles using magnesium stearate.

[0019] In the technical solution of this invention, the team discovered that the prepared powdered calcium lactate exhibited inconsistent quality. In-depth research revealed a significant influence from the binding force between the middle and inner coating layers. Since the bond between the inner and middle coating layers is a simple physical interaction, the middle coating layer easily detaches from the inner coating layer under external forces such as impacts during the calcium lactate powder's formation. This results in a decrease in the sustained-release and anti-caking properties of the calcium lactate powder, ultimately leading to inconsistent product quality. To further address this technical problem, this invention adds modified calcium chloride to the inner coating layer, thereby achieving a bond between the -NH2 on the chitosan oligosaccharide in the middle coating layer and the Ca2+ on the inner coating layer. 2+ Coordination bonds are formed, thereby increasing the binding force between the two and preventing the middle coating from detaching from the surface of the inner coating. In addition, the modified calcium carbonate of this invention uses magnesium stearate to hydrophobically modify the surface of calcium chloride particles, preventing it from affecting the hydrophobic properties of the inner coating. Moreover, the hydrophobically modified calcium chloride can improve its compatibility with the inner coating, allowing it to be better dispersed in the inner coating.

[0020] Preferably, the weight-average molecular weight of the chitosan oligosaccharide in the middle coating is 3–8 kDa.

[0021] Preferably, the weight ratio of zein, glycerol, triethyl citrate and propyl gallate in the middle coating is 100:20-25:4-7:1-2.

[0022] A powdered calcium lactate is prepared by the method described above.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. The plant-based elastomer membrane formed by the outer coating can block both oxygen and water vapor. Together with the hydrophobic barrier of the inner coating, it effectively prevents calcium lactate from absorbing moisture from the air, preventing it from absorbing moisture and clumping during storage or processing, and improving the product's fluidity, dispersibility and shelf life.

[0025] 2. The hydrophobic layer formed by the inner coating can shield the calcium ions in calcium lactate from direct contact with the taste buds, thereby preventing bitterness from overflowing in the mouth, improving the palatability of the product, which is conducive to increasing the acceptance of calcium-containing foods by infants and young children and enhancing the effectiveness of calcium supplementation.

[0026] 3. The middle coating utilizes chitosan oligosaccharide to coordinate and cross-link with calcium ions to form a film. The swollen chitosan can play a sustained-release role, so that after calcium lactate enters the human body, calcium ions are released slowly, avoiding a sudden increase in the local calcium ion concentration in the gastrointestinal tract, reducing irritation to the gastrointestinal mucosa, and reducing the occurrence of discomfort symptoms such as abdominal distension and diarrhea.

[0027] 4. By adding calcium chloride modified with magnesium stearate hydrophobically to the inner coating, the amino groups on the chitosan oligosaccharide in the middle coating can form coordination bonds with the calcium ions in the inner coating, thereby enhancing the binding force between the middle and inner coatings, preventing the middle coating from falling off, and thus improving the sustained-release performance and anti-caking performance of powdered calcium lactate, ensuring the consistency of product quality. Attached Figure Description

[0028] Figure 1 This is a SEM image of the powdered calcium lactate particles prepared according to the present invention. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] A method for preparing powdered calcium lactate includes the following steps:

[0032] Step 1: Add 200g of food-grade calcium carbonate to a jacketed reactor, followed by dropwise addition of 700g of 80wt% lactic acid aqueous solution. Maintain mechanical stirring at 80℃ and 400rpm. Stop adding the solution when the pH drops to 6.5, and continue stirring for 30min to generate a calcium lactate solution. Cool the calcium lactate solution to 15℃ at a constant rate of 1℃ / min and allow it to crystallize for 4h. Then centrifuge at 5000rpm for 10min, discard the mother liquor, and collect the calcium lactate crystals.

[0033] Step 2: Spread the calcium lactate crystals evenly on a tray and dry them in a forced-air drying oven at 100℃ until the moisture content is ≤1.5wt%. After drying, the material is crushed by a universal pulverizer and passed through a 60-mesh sieve to obtain calcium lactate intermediate, which is then sealed for later use.

[0034] Step 3: Weigh 90g of caprylic / capric triglyceride, 14g of malic acid, and 1.8g of zinc acetate into a beaker and heat in an 80℃ water bath until completely melted; then add 3g of modified calcium chloride and stir magnetically for 10min to obtain a uniform inner coating solution, and keep it at 75℃ for later use. Add 300g of calcium lactate intermediate to a WBF-0.5 fluidized bed and preheat the inlet air temperature to 60℃ for 5min; spray the inner coating solution at an atomization pressure of 0.4 MPa and a flow rate of 5 mL / min for 30min; after spraying, continue fluidized drying for 5min to obtain inner-coated particles.

[0035] Step 4: Weigh 6g of chitosan oligosaccharide with a weight-average molecular weight of 6kDa and dissolve it in 294 mL of deionized water. Add 0.9g of food-grade calcium chloride, stir until clear, and adjust the pH to 5.5 to obtain the middle coating solution. Keep it at 55℃ for later use. Put the inner-layer coated particles back into the fluidized bed with an inlet air temperature of 55℃. Spray the middle coating solution at an atomization pressure of 0.3MPa and a flow rate of 8mL / min for 40min. After spraying, dry at 55℃ for 10min to obtain double-layer coated particles.

[0036] Step 5: Weigh 20g of zein, 4.8g of glycerol, 1.2g of triethyl citrate, and 0.3g of propyl gallate, dissolve them in 120mL of 85% ethanol, and stir at 40℃ until completely dissolved to obtain the outer coating solution. Keep it at 40℃ for later use. Put the double-coated particles into a fluidized bed with an inlet air temperature of 40℃; spray the outer coating solution at an atomization pressure of 0.25MPa and a flow rate of 6mL / min for 45 minutes; after spraying, dry at 40℃ for 15 minutes, and granulate through a 60-mesh sieve to obtain the three-layer coated calcium lactate powder product.

[0037] Preparation of modified calcium chloride:

[0038] 100g of calcium chloride particles were pre-dried in a vacuum oven at 105℃ for 30 min to remove surface adsorbed water. While still hot, the particles were transferred to a 500mL high-speed shear mixing vessel. 0.5g of food-grade magnesium stearate was weighed and directly added into the vessel at 80℃ and normal pressure. The shearing paddle was started at 600rpm for 15 min to dry mix the magnesium stearate, which melted under heat and spread evenly on the surface of calcium chloride under mechanical shearing. The mixture was then cooled to room temperature to obtain the final product.

[0039] Example 2

[0040] A method for preparing powdered calcium lactate includes the following steps:

[0041] Step 1: Add 200g of food-grade calcium carbonate to a jacketed reactor, followed by dropwise addition of 600g of 80wt% lactic acid aqueous solution. Maintain mechanical stirring at 80℃ and 400rpm until the pH drops to 6.5, then stop the dropwise addition and continue stirring for 30min to generate a calcium lactate solution. Cool the calcium lactate solution uniformly to 15℃ at a rate of 1℃ / min and allow it to crystallize for 4h. Then centrifuge at 5000rpm for 10min, discard the mother liquor, and collect the calcium lactate crystals.

[0042] Step 2: Spread the calcium lactate crystals evenly on a tray and dry them in a forced-air drying oven at 100℃ until the moisture content is ≤1.5wt%. After drying, the material is crushed by a universal pulverizer and passed through a 60-mesh sieve to obtain calcium lactate intermediate, which is then sealed for later use.

[0043] Step 3: Weigh 90g of caprylic / capric triglyceride, 12g of malic acid, and 1.0g of zinc acetate into a beaker and heat in an 80℃ water bath until completely melted; then add 3g of modified calcium chloride and stir magnetically for 10min to obtain a uniform inner coating solution, and keep it at 75℃ for later use. Add 300g of calcium lactate intermediate to a WBF-0.5 fluidized bed and preheat the inlet air temperature to 60℃ for 5min; spray the inner coating solution at an atomization pressure of 0.4 MPa and a flow rate of 5 mL / min for 30min; after spraying, continue fluidized drying for 5min to obtain inner-coated particles.

[0044] Step 4: Weigh 6g of chitosan oligosaccharide with a weight-average molecular weight of 4kDa and dissolve it in 294 mL of deionized water. Add 0.9g of food-grade calcium chloride, stir until clear, and adjust the pH to 5.5 to obtain the middle coating solution. Keep it at 55℃ for later use. Put the inner-layer coated particles back into the fluidized bed with an inlet air temperature of 55℃. Spray the middle coating solution at an atomization pressure of 0.3MPa and a flow rate of 8mL / min for 40min. After spraying, dry at 55℃ for 10min to obtain double-layer coated particles.

[0045] Step 5: Weigh 20g of zein, 4.2g of glycerol, 0.9g of triethyl citrate, and 0.3g of propyl gallate, dissolve them in 120mL of 85% ethanol, and stir at 40℃ until completely dissolved to obtain the outer coating solution. Keep it at 40℃ for later use. Put the double-coated particles into a fluidized bed with an inlet air temperature of 40℃; spray the outer coating solution at an atomization pressure of 0.25MPa and a flow rate of 6mL / min for 45 minutes; after spraying, dry at 40℃ for 15 minutes, and granulate through a 60-mesh sieve to obtain the three-layer coated calcium lactate powder product.

[0046] Preparation of modified calcium chloride:

[0047] 100g of calcium chloride particles were pre-dried in a vacuum oven at 105℃ for 30 min to remove surface adsorbed water. While still hot, the particles were transferred to a 500mL high-speed shear mixing vessel. 0.5g of food-grade magnesium stearate was weighed and directly added into the vessel at 80℃ and normal pressure. The shearing paddle was started at 600rpm for 15 min to dry mix the magnesium stearate, which melted under heat and spread evenly on the surface of calcium chloride under mechanical shearing. The mixture was then cooled to room temperature to obtain the final product.

[0048] Example 3

[0049] A method for preparing powdered calcium lactate includes the following steps:

[0050] Step 1: Add 200g of food-grade calcium carbonate to a jacketed reactor, followed by dropwise addition of 650g of 80wt% lactic acid aqueous solution. Maintain mechanical stirring at 80℃ and 400rpm until the pH drops to 6.5. Stop adding the solution and continue stirring for 30min to generate a calcium lactate solution. Cool the calcium lactate solution to 15℃ at a constant rate of 1℃ / min and allow it to crystallize for 4h. Then centrifuge at 5000rpm for 10min, discard the mother liquor, and collect the calcium lactate crystals.

[0051] Step 2: Spread the calcium lactate crystals evenly on a tray and dry them in a forced-air drying oven at 100℃ until the moisture content is ≤1.5wt%. After drying, the material is crushed by a universal pulverizer and passed through a 60-mesh sieve to obtain calcium lactate intermediate, which is then sealed for later use.

[0052] Step 3: Weigh 90g of caprylic / capric triglyceride, 13g of malic acid, and 1.5g of zinc acetate into a beaker and heat in an 80℃ water bath until completely melted; then add 3g of modified calcium chloride and stir magnetically for 10min to obtain a uniform inner coating solution, and keep it at 75℃ for later use. Add 300g of calcium lactate intermediate to a WBF-0.5 fluidized bed and preheat the inlet air temperature to 60℃ for 5min; spray the inner coating solution at an atomization pressure of 0.4 MPa and a flow rate of 5 mL / min for 30min; after spraying, continue fluidized drying for 5min to obtain inner-coated particles.

[0053] Step 4: Weigh 6g of chitosan oligosaccharide with a weight-average molecular weight of 5kDa and dissolve it in 294 mL of deionized water. Add 0.9g of food-grade calcium chloride, stir until clear, and adjust the pH to 5.5 to obtain the middle coating solution. Keep it at 55℃ for later use. Put the inner-layer coated particles back into the fluidized bed with an inlet air temperature of 55℃. Spray the middle coating solution at an atomization pressure of 0.3MPa and a flow rate of 8mL / min for 40min. After spraying, dry at 55℃ for 10min to obtain double-layer coated particles.

[0054] Step 5: Weigh 20g of zein, 4.5g of glycerol, 1.0g of triethyl citrate, and 0.3g of propyl gallate, dissolve them in 120mL of 85% ethanol, and stir at 40℃ until completely dissolved to obtain the outer coating solution. Keep it at 40℃ for later use. Put the double-coated particles into a fluidized bed with an inlet air temperature of 40℃; spray the outer coating solution at an atomization pressure of 0.25MPa and a flow rate of 6mL / min for 45 minutes; after spraying, dry at 40℃ for 15 minutes, and granulate through a 60-mesh sieve to obtain the three-layer coated calcium lactate powder product.

[0055] Preparation of modified calcium chloride:

[0056] 100g of calcium chloride particles were pre-dried in a vacuum oven at 105℃ for 30 min to remove surface adsorbed water. While still hot, the particles were transferred to a 500mL high-speed shear mixing vessel. 0.5g of food-grade magnesium stearate was weighed and directly added into the vessel at 80℃ and normal pressure. The shearing paddle was started at 600rpm for 15 min to dry mix the magnesium stearate, which melted under heat and spread evenly on the surface of calcium chloride under mechanical shearing. The mixture was then cooled to room temperature to obtain the final product.

[0057] Example 4

[0058] A method for preparing powdered calcium lactate includes the following steps:

[0059] Step 1: Add 200g of food-grade calcium carbonate to a jacketed reactor, followed by dropwise addition of 750g of 80wt% lactic acid aqueous solution. Maintain mechanical stirring at 80℃ and 400rpm until the pH drops to 6.5, then stop the dropwise addition and continue stirring for 30min to generate a calcium lactate solution. Cool the calcium lactate solution uniformly to 15℃ at a rate of 1℃ / min and allow it to crystallize for 4h. Then centrifuge at 5000rpm for 10min, discard the mother liquor, and collect the calcium lactate crystals.

[0060] Step 2: Spread the calcium lactate crystals evenly on a tray and dry them in a forced-air drying oven at 120℃ until the moisture content is ≤1.5wt%. After drying, the material is crushed by a universal pulverizer and passed through a 60-mesh sieve to obtain calcium lactate intermediate, which is then sealed for later use.

[0061] Step 3: Weigh 90g of caprylic / capric triglyceride, 15g of malic acid, and 2.0g of zinc acetate into a beaker and heat in an 80℃ water bath until completely melted; then add 3g of modified calcium chloride and stir magnetically for 10min to obtain a uniform inner coating solution, and keep it at 75℃ for later use. Add 300g of calcium lactate intermediate to a WBF-0.5 fluidized bed and preheat the inlet air temperature to 60℃ for 5min; spray the inner coating solution at an atomization pressure of 0.4 MPa and a flow rate of 5 mL / min for 30min; after spraying, continue fluidized drying for 5min to obtain inner-coated particles.

[0062] Step 4: Weigh 6g of chitosan oligosaccharide with a weight-average molecular weight of 8kDa and dissolve it in 294 mL of deionized water. Add 0.9g of food-grade calcium chloride, stir until clear, and adjust the pH to 5.5 to obtain the middle coating solution. Keep it at 55℃ for later use. Put the inner-layer coated particles back into the fluidized bed with an inlet air temperature of 55℃. Spray the middle coating solution at an atomization pressure of 0.3MPa and a flow rate of 8mL / min for 40min. After spraying, dry at 55℃ for 10min to obtain double-layer coated particles.

[0063] Step 5: Weigh 20g of zein, 5g of glycerol, 1.4g of triethyl citrate, and 0.4g of propyl gallate, dissolve them in 120mL of 85% ethanol, and stir at 40℃ until completely dissolved to obtain the outer coating solution. Keep it at 40℃ for later use. Put the double-coated particles into a fluidized bed with an inlet air temperature of 40℃; spray the outer coating solution at an atomization pressure of 0.25MPa and a flow rate of 6mL / min for 45 minutes; after spraying, dry at 40℃ for 15 minutes, and granulate through a 60-mesh sieve to obtain the three-layer coated calcium lactate powder product.

[0064] Preparation of modified calcium chloride:

[0065] 100g of calcium chloride particles were pre-dried in a vacuum oven at 105℃ for 30 min to remove surface adsorbed water. While still hot, the particles were transferred to a 500mL high-speed shear mixing vessel. 0.5g of food-grade magnesium stearate was weighed and directly added into the vessel at 80℃ and normal pressure. The shearing paddle was started at 600rpm for 15 min to dry mix the magnesium stearate, which melted under heat and spread evenly on the surface of calcium chloride under mechanical shearing. The mixture was then cooled to room temperature to obtain the final product.

[0066] Example 5

[0067] A method for preparing powdered calcium lactate includes the following steps:

[0068] Step 1: Add 200g of food-grade calcium carbonate to a jacketed reactor, followed by dropwise addition of 500g of 80wt% lactic acid aqueous solution. Maintain mechanical stirring at 80℃ and 400rpm until the pH drops to 6.5, then stop the dropwise addition and continue stirring for 30min to generate a calcium lactate solution. Cool the calcium lactate solution uniformly to 15℃ at a rate of 1℃ / min and allow it to crystallize for 4h. Then centrifuge at 5000rpm for 10min, discard the mother liquor, and collect the calcium lactate crystals.

[0069] Step 2: Spread the calcium lactate crystals evenly on a tray and dry them in a forced-air drying oven at 80°C until the moisture content is ≤1.5wt%. After drying, the material is crushed by a universal pulverizer and passed through a 60-mesh sieve to obtain calcium lactate intermediate, which is then sealed for later use.

[0070] Step 3: Weigh 90g of caprylic / capric triglyceride, 10g of malic acid, and 0.5g of zinc acetate into a beaker and heat in an 80℃ water bath until completely melted; then add 3g of modified calcium chloride and stir magnetically for 10min to obtain a uniform inner coating solution, and keep it at 75℃ for later use. Add 300g of calcium lactate intermediate to a WBF-0.5 fluidized bed and preheat the inlet air temperature to 60℃ for 5min; spray the inner coating solution at an atomization pressure of 0.4 MPa and a flow rate of 5 mL / min for 30min; after spraying, continue fluidized drying for 5min to obtain inner-coated particles.

[0071] Step 4: Weigh 6g of chitosan oligosaccharide with a weight-average molecular weight of 3kDa and dissolve it in 294 mL of deionized water. Add 0.9g of food-grade calcium chloride, stir until clear, and adjust the pH to 5.5 to obtain the middle coating solution. Keep it at 55℃ for later use. Put the inner-layer coated particles back into the fluidized bed with an inlet air temperature of 55℃. Spray the middle coating solution at an atomization pressure of 0.3MPa and a flow rate of 8mL / min for 40min. After spraying, dry at 55℃ for 10min to obtain double-layer coated particles.

[0072] Step 5: Weigh 20g of zein, 4g of glycerol, 0.8g of triethyl citrate, and 0.2g of propyl gallate, dissolve them in 120mL of 85% ethanol, and stir at 40℃ until completely dissolved to obtain the outer coating solution. Keep it at 40℃ for later use. Put the double-coated particles into a fluidized bed with an inlet air temperature of 40℃; spray the outer coating solution at an atomization pressure of 0.25MPa and a flow rate of 6mL / min for 45 minutes; after spraying, dry at 40℃ for 15 minutes, and granulate through a 60-mesh sieve to obtain the three-layer coated calcium lactate powder product.

[0073] Preparation of modified calcium chloride:

[0074] 100g of calcium chloride particles were pre-dried in a vacuum oven at 105℃ for 30 min to remove surface adsorbed water. While still hot, the particles were transferred to a 500mL high-speed shear mixing vessel. 0.5g of food-grade magnesium stearate was weighed and directly added into the vessel at 80℃ and normal pressure. The shearing paddle was started at 600rpm for 15 min to dry mix the magnesium stearate, which melted under heat and spread evenly on the surface of calcium chloride under mechanical shearing. The mixture was then cooled to room temperature to obtain the final product.

[0075] Comparative Example 1

[0076] The difference between Comparative Example 1 and Example 1 is that steps 3, 4 and 5 are omitted in the preparation of powdered calcium lactate.

[0077] Comparative Example 2

[0078] The difference between Comparative Example 2 and Example 1 is that steps 4 and 5 are omitted in the preparation of powdered calcium lactate.

[0079] Comparative Example 3

[0080] The difference between Comparative Example 3 and Example 1 is that step 5 is omitted in the preparation of powdered calcium lactate.

[0081] Comparative Example 4

[0082] The difference between Comparative Example 4 and Example 1 is that modified calcium chloride is not added in step 3 of the preparation process of powdered calcium lactate.

[0083] Comparative Example 5

[0084] The difference between Comparative Example 5 and Example 1 is that modified calcium chloride was replaced with ordinary calcium chloride in the preparation of powdered calcium lactate.

[0085] Performance testing:

[0086] 1. Hygroscopicity (Anti-caking) Test: Weigh 5g of each sample and place it in a 5cm diameter weighing bottle (open). Place the bottle in a constant temperature and humidity chamber at 30℃ and 75% relative humidity for 72h. Weigh the sample after moisture absorption and calculate the moisture absorption weight gain rate (%) = (weight after moisture absorption - initial weight) / initial weight × 100%. The lower the moisture absorption weight gain rate, the better the anti-caking performance. The test results are shown in Table 1.

[0087] 2. Bitterness Masking Effect Test: Ten trained sensory evaluators conducted a blind evaluation of the bitterness of each sample, using a 10-point scoring system (0 points = no bitterness, 10 points = extremely bitterness). The average score was taken as the bitterness score. The lower the score, the better the bitterness masking effect. The test results are shown in Table 1.

[0088] 3. Calcium ion sustained-release performance test: The dissolution test method (paddle method) according to the Chinese Pharmacopoeia was adopted. 900 mL of artificial gastric fluid (pH=1.2, 37℃±0.5℃, rotation speed 50 rpm) was used as the medium. The sample (containing Ca) was added... 2+ Samples (0.5 g) were taken at 15 min and 120 min, and the calcium ion concentration was determined by EDTA titration to calculate the cumulative release rate. Samples with excellent sustained-release effects showed a low release rate at 15 min, but a release rate exceeding 80% at 120 min. The test results are shown in Table 1.

[0089] 4. Coating bonding stability test: Weigh 20g of each sample and place it in a 50mL centrifuge tube. Shake at a frequency of 200 times / min for 2 hours on a reciprocating shaker. After removal, observe the integrity of the film on the particle surface under a microscope and count the proportion of damaged particles to the total number of particles (film breakage rate). The lower the breakage rate, the more stable the coating bonding. The test results are shown in Table 1.

[0090] Table 1:

[0091]

[0092] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing powdered calcium lactate, characterized in that, Includes the following steps: a) Calcium lactate crystals are prepared by reacting calcium carbonate with lactic acid; b) Dry and pulverize the calcium lactate crystals to obtain the calcium lactate intermediate; c) The calcium lactate intermediate is coated in three layers sequentially in a fluidized bed and then dried to obtain the final product; The three layers of coating are as follows: Inner coating: A coating solution composed of caprylic / capric triglyceride, malic acid, and zinc acetate is sprayed onto the inner coating, causing the malic acid to undergo in-situ esterification with the hydroxyl groups on the surface of calcium lactate, forming a hydrophobic inner layer. Modified calcium chloride is also added to the inner coating. The modified calcium chloride is obtained by hydrophobically modifying the surface of calcium chloride particles with magnesium stearate. The weight ratio of caprylic / capric triglyceride, malic acid, zinc acetate, and modified calcium chloride in the inner coating is 90:10-15:0.5-2:

3. Intermediate coating: A coating solution composed of chitosan oligosaccharide and calcium chloride aqueous solution is sprayed on to allow chitosan oligosaccharide to coordinate and crosslink with calcium ions, forming a controlled-release intermediate layer; the mass ratio of chitosan oligosaccharide to calcium chloride in the intermediate coating is 6:0.9; Outer coating: A coating solution composed of ethanol solution of zein, glycerol, triethyl citrate and propyl gallate is sprayed on, and an elastic outer layer is formed by free radical cross-linking initiated by propyl gallate; the weight ratio of zein, glycerol, triethyl citrate and propyl gallate in the outer coating is 100:20-25:4-7:1-2.

2. The method for preparing powdered calcium lactate according to claim 1, characterized in that, In step a), the mass ratio of calcium carbonate to lactic acid is 1:2 to 3.

3. The method for preparing powdered calcium lactate according to claim 1, characterized in that, In step b), the drying is performed by flash drying at 80–120°C or by forced air drying until the moisture content is ≤1.5 wt%.

4. The method for preparing powdered calcium lactate according to claim 1, characterized in that, The weight-average molecular weight of the chitosan oligosaccharide in the middle coating is 3–8 kDa.

5. A powdered calcium lactate, characterized in that, It is prepared by the method described in any one of claims 1-4 above.

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