Preparation method of zinc glycinate chelate

Abstract

The invention relates to the technical field of zinc glycinate production, and provides a zinc glycinate chelate preparation method, which comprises: (1) pre-mixing glycine and nano zinc oxide, adding into water, and carrying out microwave treatment and ultrasonic-assisted synergistic treatment to prepare a glycine suspension; (2) adding L-ascorbic acid, stirring, maintaining the temperature at 58-62 DEG C for 30-40 minutes, heating to 74-80 DEG C, and maintaining the temperature at 74-80 DEG C for 2-3 hours; and (3) cooling to room temperature, standing, centrifugally separating, and drying to obtain the zinc glycinate chelate. According to the preparation method of the glycine zinc chelate, the production cost is effectively reduced and the production efficiency is improved under the condition that the purity and the stability of the product are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of glycine zinc production, and specifically, to a preparation method of glycine zinc chelate. Background Art

[0002] Glycine zinc chelate is an organic zinc supplement that improves the absorption and utilization of zinc by forming a stable complex with zinc ions. Zinc is one of the essential trace elements in the human body, participating in various enzymatic reactions and playing an important role in maintaining cell growth and development and tissue repair. Zinc deficiency may lead to a series of health problems such as decreased immune function, reproductive system abnormalities, dermatitis, and hair loss. The zinc ions in glycine zinc chelate exist in a chelated form, with the characteristics of neutrality, small molecular weight, and easy overall absorption, so it can significantly improve the bioavailability of zinc.

[0003] Glycine zinc chelate has broad application prospects in the fields of medicine, health products, food, and feed. In the medical field, glycine zinc chelate can be used to treat zinc deficiency and improve various symptoms caused by zinc deficiency. In the health product field, glycine zinc chelate can be used as a nutritional supplement to enhance human immunity and promote growth and development. In the food and feed fields, glycine zinc chelate can be used as a zinc fortifier to improve the nutritional value of food and feed.

[0004] Although glycine zinc chelate has many advantages, the existing preparation methods still have some problems, which limit its large-scale production and application. Due to complex reaction conditions and the need to use high-purity raw materials and expensive equipment, the production cost of glycine zinc chelate is relatively high. This limits its application in some fields with low-cost requirements. Based on this, the present invention proposes a preparation method of glycine zinc chelate. Summary of the Invention

[0005] The present invention proposes a preparation method of glycine zinc chelate, aiming to effectively reduce the production cost and improve the production efficiency while ensuring the purity and stability of the product.

[0006] The technical solution of the present invention is as follows: The present invention proposes a preparation method of glycine zinc chelate, and the steps include: (1) Premix glycine with nano-zinc oxide and then add it to water, and perform cooperative treatment under microwave treatment and ultrasonic assistance to prepare a glycine suspension; (2) Add L-ascorbic acid and then stir, and then maintain it at a temperature of 58 - 62 °C for 30 - 40 min, and then raise the temperature to 74 - 80 °C and maintain it for 2 - 3 h; (3) Then cool it to room temperature, centrifuge and separate after standing, and dry to obtain glycine zinc chelate.

[0007] As a further technical solution, the molar ratio of glycine to nano-zinc oxide is 1:0.45 - 0.55.

[0008] As a further technical solution, the ratio of the total weight parts of glycine and nano-zinc oxide in the glycine suspension to the weight parts of water is 1:3 - 4.

[0009] As a further technical solution, the frequency of the microwave treatment is 2 - 3 GHz, and the power is 300 - 500 W.

[0010] As a further technical solution, the frequency of the ultrasound is 35 - 45 kHz, and the power is 450 - 550 W.

[0011] As a further technical solution, the time of the co-treatment is 20 - 30 min.

[0012] As a further technical solution, the weight of L-ascorbic acid is 0.05% - 0.07% of the weight of the glycine suspension.

[0013] As a further technical solution, the stirring rate is 800 - 1000 rpm, and the time is 10 - 20 min.

[0014] As a further technical solution, the cooling step includes three stages. Among them, in the first stage, it is cooled to 45 - 50 °C at a rate of 2 - 3 °C / min, in the second stage, it is cooled to 30 - 35 °C at a rate of 1 - 2 °C / min, and in the third stage, it is naturally cooled to room temperature.

[0015] As a further technical solution, the standing time is 80 - 100 min; the drying temperature is 55 - 65 °C, and the time is 6 - 8 h.

[0016] The working principle and beneficial effects of the present invention are as follows: The present invention combines the advantages of two physical fields of microwave and ultrasound, and effectively activates the surface of nano-zinc oxide through synergistic action, improving its coordination efficiency with glycine. Among them, the microwave generates an electromagnetic field, making the polar molecules in the material vibrate rapidly and generate heat, thereby achieving rapid and uniform heating; this heating method helps to activate the surface of nano-zinc oxide, making it easier to undergo a coordination reaction with glycine; the ultrasound generates a cavitation effect and mechanical vibration, which can effectively disperse the nano-zinc oxide particles and prevent their agglomeration; at the same time, the ultrasound can also promote the mixing and contact between reactants and accelerate the reaction process. The synergistic treatment of microwave and ultrasound not only accelerates the reaction process, but also improves the activation degree and dispersibility of nano-zinc oxide, thus significantly enhancing the coordination efficiency of glycine and nano-zinc oxide.

[0017] The present invention adopts a low-temperature pre-reaction and a gradient cooling procedure, optimizes the crystal growth process of zinc glycine chelate, reduces lattice defects, and improves the stability and purity of the product. The pre-reaction is carried out at 58 - 62 °C, which helps the orderly assembly and preliminary coordination between molecules. This stage is crucial for the subsequent crystal growth and stability. At the same time, by cooling in stages, the crystal growth rate and process can be effectively controlled, and the formation of lattice defects can be reduced; the gradient cooling can also enable the crystal to gradually release stress during the cooling process, improving the structural stability.

[0018] The present invention effectively inhibits the generation of oxidation by-products of glycine by adding L-ascorbic acid and combining gradient temperature control, and further improves the purity of the product. Among them, L-ascorbic acid, as an antioxidant, can effectively inhibit the generation of oxidation by-products of glycine during the reaction, such as glyoxylic acid, etc. The presence of these by-products will reduce the purity and stability of the product; in addition, through precise temperature control, the antioxidant effect of L-ascorbic acid is further optimized. Under the temperature control in this application, L-ascorbic acid can fully exert its antioxidant function while avoiding the thermal decomposition of glycine caused by too high temperature. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0020] It should be noted that the size of the nano-zinc oxide in the present invention is 20 - 30 nm.

[0021] Example 1 In this example, a preparation method of zinc glycine chelate is provided, and the steps include: Glycine and nano-zinc oxide are pre-mixed at a molar ratio of 1:0.47 and then added to water, and they are co-treated for 25 min under microwave treatment and ultrasonic assistance to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); the frequency of the microwave treatment is 2.5 GHz, and the power is 400 W; the frequency of the ultrasonic wave is 40 kHz, and the power is 500 W; L-ascorbic acid with a weight ratio of 0.06% relative to the suspension is added, and the mixed solution is stirred at a rotation speed of 900 rpm, and then maintained at 60 °C for 35 min, and then heated to 77 °C and maintained for 2.5 h; Subsequently, the temperature was decreased in three stages. Among them, in the first stage, it was decreased to 47 °C at a rate of 2.5 °C / min, in the second stage, it was decreased to 32 °C at a rate of 1.5 °C / min, and in the third stage, it was naturally cooled to room temperature. After standing for 90 min, centrifugal separation was carried out, and drying was carried out at 60 °C to obtain zinc glycine chelate.

[0022] Example 2 In this example, a preparation method of zinc glycine chelate was provided, and the steps included: Glycine and nano-zinc oxide were pre-mixed at a molar ratio of 1:0.45 and then added to water. They were co-treated under microwave treatment and ultrasonic assistance for 20 min to prepare a glycine suspension with a solid-liquid ratio of 1:3 (by weight). The frequency of microwave treatment was 2 GHz and the power was 300 W; the frequency of ultrasound was 35 kHz and the power was 4500 W; L-ascorbic acid with a weight ratio of 0.05% relative to the suspension was added, and the mixed solution was stirred at a rotation speed of 800 rpm. Subsequently, it was maintained at a temperature of 58 °C for 30 min, and then heated to 74 °C and maintained for 2 h; Subsequently, the temperature was decreased in three stages. Among them, in the first stage, it was decreased to 45 °C at a rate of 2 °C / min, in the second stage, it was decreased to 30 °C at a rate of 1 °C / min, and in the third stage, it was naturally cooled to room temperature. After standing for 80 min, centrifugal separation was carried out, and drying was carried out at 55 °C to obtain zinc glycine chelate.

[0023] Example 3 In this example, a preparation method of zinc glycine chelate was provided, and the steps included: Glycine and nano-zinc oxide were pre-mixed at a molar ratio of 1:0.5 and then added to water. They were co-treated under microwave treatment and ultrasonic assistance for 30 min to prepare a glycine suspension with a solid-liquid ratio of 1:4 (by weight). The frequency of microwave treatment was 3 GHz and the power was 500 W; the frequency of ultrasound was 45 kHz and the power was 550 W; L-ascorbic acid with a weight ratio of 0.07% relative to the suspension was added, and the mixed solution was stirred at a rotation speed of 1000 rpm. Subsequently, it was maintained at a temperature of 62 °C for 40 min, and then heated to 80 °C and maintained for 3 h; Subsequently, the temperature was decreased in three stages. Among them, in the first stage, it was decreased to 50 °C at a rate of 3 °C / min, in the second stage, it was decreased to 35 °C at a rate of 2 °C / min, and in the third stage, it was naturally cooled to room temperature. After standing for 100 min, centrifugal separation was carried out, and drying was carried out at 65 °C to obtain zinc glycine chelate.

[0024] Example 4 In this example, a preparation method of zinc glycine chelate was provided, and the steps included: Glycine and nano-zinc oxide were pre-mixed at a molar ratio of 1:0.45 and then added to water, and co-treated for 30 min under microwave treatment and ultrasonic assistance to prepare a glycine suspension with a solid-liquid ratio of 1:3 (by weight); the frequency of microwave treatment was 3 GHz and the power was 300 W; the frequency of ultrasound was 45 kHz and the power was 450 W; L-ascorbic acid with a ratio of 0.07% by weight of the suspension was added, and the mixed solution was stirred at a rotation speed of 800 rpm, and then maintained at 62 °C for 30 min, and then heated to 80 °C and maintained for 2 h; Subsequently, cooling was carried out in three stages. Among them, the first stage was cooled to 45 °C at 3 °C / min, the second stage was cooled to 35 °C at 1 °C / min, and the third stage was naturally cooled to room temperature. After standing for 80 min, centrifugal separation was carried out, and drying was carried out at 65 °C to obtain zinc glycine chelate.

[0025] Example 5 In this example, a preparation method of zinc glycine chelate is provided, and the steps include: Glycine and nano-zinc oxide were pre-mixed at a molar ratio of 1:0.47 and then added to water, and co-treated for 25 min under microwave treatment and ultrasonic assistance to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); the frequency of microwave treatment was 2.5 GHz and the power was 400 W; the frequency of ultrasound was 40 kHz and the power was 500 W; L-ascorbic acid with a ratio of 0.06% by weight of the suspension was added, and the mixed solution was stirred at a rotation speed of 900 rpm, and then maintained at 60 °C for 35 min, and then heated to 77 °C and maintained for 2.5 h; Subsequently, cooling was carried out in two stages. Among them, the first stage was cooled to 32 °C at 1.5 °C / min, and the second stage was naturally cooled to room temperature. After standing for 90 min, centrifugal separation was carried out, and drying was carried out at 60 °C to obtain zinc glycine chelate.

[0026] Example 6 In this example, a preparation method of zinc glycine chelate is provided, and the steps include: Glycine and nano-zinc oxide were pre-mixed at a molar ratio of 1:0.47 and then added to water, and co-treated for 25 min under microwave treatment and ultrasonic assistance to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); the frequency of microwave treatment was 2.5 GHz and the power was 400 W; the frequency of ultrasound was 40 kHz and the power was 500 W; Add L-ascorbic acid with a weight ratio of 0.06% relative to the suspension, stir the mixed solution at a rotation speed of 900 rpm, then maintain it at 60 °C for 35 min, and then raise the temperature to 77 °C and maintain it for 2.5 h; Then cool it naturally to room temperature, let it stand for 90 min and then centrifuge, and dry it at 60 °C to obtain zinc glycine chelate.

[0027] Example 7 In this example, a method for preparing zinc glycine chelate is provided, and the steps include: Pre-mix glycine and nano-zinc oxide at a molar ratio of 1:0.47 and then add them to water, and co-treat them under microwave treatment and ultrasonic assistance for 25 min to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); the frequency of microwave treatment is 2.5 GHz and the power is 400 W; the frequency of ultrasound is 40 kHz and the power is 500 W; Add L-ascorbic acid with a weight ratio of 0.06% relative to the suspension, stir the mixed solution at a rotation speed of 900 rpm, then maintain it at 60 °C for 35 min, and then raise the temperature to 77 °C and maintain it for 2.5 h; Then cool down in three stages. Among them, the first stage is cooled to 47 °C at 4 °C / min, the second stage is cooled to 32 °C at 3 °C / min, and the third stage is cooled naturally to room temperature. Let it stand for 90 min and then centrifuge, and dry it at 60 °C to obtain zinc glycine chelate.

[0028] Example 8 In this example, a method for preparing zinc glycine chelate is provided, and the steps include: Pre-mix glycine and nano-zinc oxide at a molar ratio of 1:0.47 and then add them to water, and co-treat them under microwave treatment and ultrasonic assistance for 25 min to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); the frequency of microwave treatment is 2.5 GHz and the power is 400 W; the frequency of ultrasound is 40 kHz and the power is 500 W; Add L-ascorbic acid with a weight ratio of 0.06% relative to the suspension, stir the mixed solution at a rotation speed of 900 rpm, then maintain it at 60 °C for 35 min, and then raise the temperature to 77 °C and maintain it for 2.5 h; Then cool down in three stages. Among them, the first stage is cooled to 47 °C at 1 °C / min, the second stage is cooled to 32 °C at 0.5 °C / min, and the third stage is cooled naturally to room temperature. Let it stand for 90 min and then centrifuge, and dry it at 60 °C to obtain zinc glycine chelate.

[0029] Comparative Example 1 In this comparative example, a preparation method of zinc glycine chelate is provided, and the steps include: Glycine and nano-zinc oxide are pre-mixed at a molar ratio of 1:0.47 and then added to water, and microwave treatment is carried out for 25 min to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); the frequency of microwave treatment is 2.5 GHz and the power is 400 W; L-ascorbic acid with a weight ratio of 0.06% relative to the suspension is added, and the mixed solution is stirred at a rotation speed of 900 rpm, then maintained at 60 °C for 35 min, and then heated to 77 °C and maintained for 2.5 h; Subsequently, cooling is carried out in three stages. Among them, the first stage is cooled to 47 °C at 2.5 °C / min, the second stage is cooled to 32 °C at 1.5 °C / min, and the third stage is naturally cooled to room temperature. After standing for 90 min, centrifugal separation is carried out, and drying is carried out at 60 °C to obtain zinc glycine chelate.

[0030] Comparative Example 2 In this comparative example, a preparation method of zinc glycine chelate is provided, and the steps include: Glycine and nano-zinc oxide are pre-mixed at a molar ratio of 1:0.47 and then added to water, and treatment is carried out for 25 min under ultrasonic assistance to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); the frequency of ultrasound is 40 kHz and the power is 500 W; L-ascorbic acid with a weight ratio of 0.06% relative to the suspension is added, and the mixed solution is stirred at a rotation speed of 900 rpm, then maintained at 60 °C for 35 min, and then heated to 77 °C and maintained for 2.5 h; Subsequently, cooling is carried out in three stages. Among them, the first stage is cooled to 47 °C at 2.5 °C / min, the second stage is cooled to 32 °C at 1.5 °C / min, and the third stage is naturally cooled to room temperature. After standing for 90 min, centrifugal separation is carried out, and drying is carried out at 60 °C to obtain zinc glycine chelate.

[0031] Comparative Example 3 In this comparative example, a preparation method of zinc glycine chelate is provided, and the steps include: Glycine and nano-zinc oxide are pre-mixed at a molar ratio of 1:0.47 and then added to water to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight); L-ascorbic acid with a weight ratio of 0.06% relative to the suspension is added, and the mixed solution is stirred at a rotation speed of 900 rpm, then maintained at 60 °C for 35 min, and then heated to 77 °C and maintained for 2.5 h; Subsequently, the temperature was decreased in three stages. Among them, in the first stage, it was decreased to 47°C at a rate of 2.5°C / min, in the second stage, it was decreased to 32°C at a rate of 1.5°C / min, and in the third stage, it was naturally cooled to room temperature. After standing for 90 min, centrifugal separation was carried out, and then drying was carried out at 60°C to obtain zinc glycine chelate.

[0032] Comparative Example 4 In this comparative example, a preparation method of zinc glycine chelate was provided, and the steps included: Glycine and nano-zinc oxide were premixed at a molar ratio of 1:0.47 and then added to water, and they were co-treated for 25 min under microwave treatment and ultrasonic assistance to prepare a glycine suspension with a solid-liquid ratio of 1:3.5 (by weight). The frequency of microwave treatment was 2.5 GHz, and the power was 400 W; the frequency of ultrasonic was 40 kHz, and the power was 500 W; L-ascorbic acid with a weight ratio of 0.06% relative to the suspension was added, and the mixed solution was stirred at a rotation speed of 900 rpm, and then the temperature was raised to 77°C and maintained for 2.5 h; Subsequently, the temperature was decreased in three stages. Among them, in the first stage, it was decreased to 47°C at a rate of 2.5°C / min, in the second stage, it was decreased to 32°C at a rate of 1.5°C / min, and in the third stage, it was naturally cooled to room temperature. After standing for 90 min, centrifugal separation was carried out, and then drying was carried out at 60°C to obtain zinc glycine chelate.

[0033] Test Example 1: The products prepared in the foregoing Examples 1-8 and Comparative Examples 1-4 were tested as follows: 1. Chelation degree: Refer to GB / T 13082-2023 "Determination of Chelation Rate of Trace Element Chelates in Feed Additives"; 2. Stability: Store at 40°C / 75% RH for 6 months, test the chelation degree and calculate the chelation degree decline rate; 3. Purity: Test by high performance liquid chromatography; Among them, the chromatographic column was an Agilent Eclipse XDB C18 column (250×4.6 mm, 5 μm), the mobile phase was 0.1% acetonitrile-phosphoric acid aqueous solution (the volume ratio of phosphoric acid to water was 15:85), the flow rate was 1.0 mL / min, and the detection wavelength was 210 nm.

[0034] The test results are shown in Table 1 below: Table 1

[0035] Combined with the above data, it can be seen that the chelation degree of Comparative Example 1 is significantly lower than that of Example 1 (97.5%), indicating that simple microwave treatment cannot fully activate the surface of nano-zinc oxide, resulting in insufficient coordination efficiency. The chelation degree of Comparative Example 2 is slightly higher than that of Comparative Example 1 but lower than that of the example, indicating that although ultrasonic cavitation can promote dispersion, it lacks the synergistic effect of the electromagnetic field of microwaves and has a higher reaction activation energy. The chelation degree of Comparative Example 3 is the lowest and the purity decreases significantly, proving that microwave-ultrasonic synergistic treatment is the key step to improve the reaction activity. The chelation degree of Comparative Example 4 decreases by 7.4%, indicating that the pre-reaction stage at 58-62 °C is crucial for the ordered molecular assembly and directly affects the product stability. Although the chelation degree of Example 5 is relatively high, the chelation degree decrease rate (3.2%) is still higher than that of the examples (1.1%-1.4%), indicating that the three-stage gradient cooling can optimize crystal growth and reduce lattice defects. The chelation degree and stability of Example 6 deteriorate, proving that rapid natural cooling will lead to crystal stress accumulation and reduce structural stability.

[0036] In addition, the high purity of Examples 1-4 benefits from the synergistic antioxidant effect of L-ascorbic acid and gradient temperature control, which inhibits the generation of glycine oxidation by-products (such as glyoxylic acid). The decrease in purity of Comparative Example 3 is due to the agglomeration of nano-zinc oxide caused by the lack of microwave-ultrasonic synergistic treatment, resulting in an increase in local pH and triggering the thermal decomposition of glycine, generating more impurities.

[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing zinc glycine chelate, characterized in that the steps include: (1) Glycine and nano zinc oxide are pre-mixed and added into water, and then synergistically treated under microwave treatment and ultrasound assistance to prepare a glycine suspension; (2) After adding L-ascorbic acid, stir and then maintain the temperature at 58-62°C for 30-40 minutes, then raise the temperature to 74-80°C and maintain for 2-3 hours; (3) The mixture is then cooled to room temperature, allowed to stand, centrifuged, and dried to obtain zinc glycine chelate.

2. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The molar ratio of glycine to nano zinc oxide is 1:0.45-0.

55.

3. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The weight ratio of the total weight of glycine and nano zinc oxide to the weight of water in the glycine suspension is 1:3-4.

4. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The frequency of the microwave treatment is 2-3 GHz, and the power is 300-500 W.

5. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The frequency of the ultrasound is 35-45kHz, and the power is 450-550W.

6. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The time of the co-treatment is 20-30 minutes.

7. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The weight of the L-ascorbic acid is 0.05%-0.07% of the weight of the glycine suspension.

8. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The stirring speed is 800-1000 rpm, and the time is 10-20 min.

9. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The cooling step includes three stages, wherein the first stage is to cool to 45-50°C at 2-3°C / min, the second stage is to cool to 30-35°C at 1-2°C / min, and the third stage is to cool naturally to room temperature.

10. The method for preparing a zinc glycine chelate according to claim 1, characterized in that: The standing time is 80-100 minutes; the drying temperature is 55-65° C., and the drying time is 6-8 hours.

Images