A method for preparing a food-grade zinc glycinate chelate

Abstract

The application discloses a preparation method of a food-grade zinc glycinate chelate, and is characterized by comprising the following steps: a synthesis reaction: glycine, a zinc source, a catalyst and water are put into a reaction kettle, are stirred and mixed, are heated to 70-90 DEG C, and are reacted for 0.5-2 hours to obtain a reaction liquid; purification and crystallization: the reaction liquid is filtered while hot, is then added into a crystallization kettle to be cooled and crystallized, is centrifugally separated, and the solid product is dried and sterilized to obtain a zinc glycinate chelate product.

Description

TECHNICAL FIELD

[0001] The utility model relates to a food -grade glycine zinc chelate preparation method. BACKGROUND

[0002] Zinc is one of the essential trace elements of human body, and is called "life element" due to its wide physiological and biochemical effects in human body. So far, the zinc supplement for human body has experienced three stages: the first stage is inorganic zinc salt mainly with zinc sulfate, which is gradually eliminated because of its low price, easy moisture absorption, low bioavailability, poor taste, and many side effects after taking. The second stage is organic weak acid zinc supplement represented by zinc gluconate, which has better absorption than inorganic zinc salt, but its synthesis is complex, the yield is low, and the zinc content is low, which is not suitable for the zinc supplement of diabetic patients. The third stage is amino acid chelated zinc synthesized by amino acid ligand and zinc salt, which has good solubility, easy absorption, chemical stability, high bioavailability, and double nutritional advantages. At present, amino acid zinc chelate has become a research hotspot, especially glycine chelated zinc with the smallest molecular weight.

[0003] Although glycine zinc has been approved as a food additive in China, there are still many reports on the synthesis method of glycine zinc. For example, in the patent CN101531608A, zinc oxide is used as the zinc source to prepare glycine zinc without anion, but the reaction time is too long, the water consumption is large, the post-treatment is difficult, and the energy consumption is too high to be industrialized. In the patent CN108383746A, the molecular formula of glycine zinc is Zn(OOCCH2NH2)2·0.5H2O, while the national standard GB1903.2-2015 clearly defines the molecular formula of glycine zinc as Zn(OOCCH2NH2)2, and the drying loss is less than 0.5%. However, the removal of crystal water in the industrial production of glycine zinc requires high energy consumption and difficult post-treatment. SUMMARY

[0004] The present application provides a food-grade glycine zinc chelate preparation method, which solves the problem of long reaction time, difficult post-treatment and high energy consumption in the existing glycine zinc production process.

[0005] To solve the above technical problems, the technical solution of the present application is as follows:

[0006] The present application provides a food-grade glycine zinc chelate preparation method, which includes the following steps:

[0007] (1) Synthesis reaction: glycine, zinc source, catalyst and water are put into a reaction kettle, stirred and mixed, heated to 70-90℃, and reacted for 0.5-2h to obtain a reaction liquid;

[0008] (2) purification and crystallization: the reaction solution is filtered while hot, then is added into a crystallization kettle for cooling and crystallization, centrifugal separation, drying and sterilization of the solid product to obtain the zinc glycinate chelate product.

[0009] Preferably, the zinc source is zinc carbonate, zinc hydroxide or zinc oxide.

[0010] Preferably, the catalyst is edible acetic acid.

[0011] Preferably, the molar ratio of glycine to the zinc source is 2:1.05-2:1.2.

[0012] Preferably, the molar ratio of glycine to the catalyst is 1:0.01-1:0.1.

[0013] Preferably, the amount of water added in step (1) is 200-350 L per kilogram of glycine.

[0014] Preferably, the reaction mother liquor after the reaction solution is filtered while hot in step (2) is recycled.

[0015] The catalyst mechanism in the present application is exemplified by zinc carbonate:

[0016] ZnCO3+2HAc→ZnAc2+H2O+CO2

[0017] ZnAc2+2Gly→Zn(Gly)2+2HAc

[0018] The addition of acetic acid not only promotes the dissolution of the insoluble zinc source, but also accelerates the reaction and acts as a catalyst.

[0019] The present application has the following advantages:

[0020] The present application uses zinc carbonate, zinc hydroxide or zinc oxide as the zinc source, and reacts with glycine under the action of a catalyst, with small water consumption, mild reaction conditions, short reaction time, simple post-treatment, low energy consumption and easy industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0022] Figure 1 The infrared absorption spectrum of the zinc glycinate chelate prepared in Example 1 of the present application,

[0023] Figure 2 Thermogravimetric chart of the zinc glycinate chelate prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0024] The technical solutions of the present application will be described clearly and completely below in combination with specific examples of the present application. Obviously, the described examples are only some of the examples of the present application, but not all the examples. Based on the examples in the present application, all the other examples obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] Example 1

[0026] The present example provides a preparation method of food-grade zinc glycinate chelate, comprising the following steps:

[0027] (1) Synthesis reaction: glycine 150 kg (2 kilomoles), zinc carbonate 131.7 kg (1.05 kilomoles), edible acetic acid 6 kg (0.1 kilomoles) and water 400 L are put into a reaction kettle, stirred and mixed, heated to 70℃, and the reaction liquid is obtained after 0.5 h of reaction;

[0028] (2) Purification and crystallization: the reaction liquid is filtered while hot, then added into a crystallization kettle for cooling and crystallization, centrifuged, and the solid product is dried and sterilized to obtain zinc glycinate chelate product 118.2 kg, with a yield of 55.5%, and the product purity is 99.82% after detection, which meets the national standard.

[0029] The infrared absorption spectrum of the zinc glycinate chelate prepared in the present example is shown in Figure 1 The infrared absorption spectrum shows that the characteristic absorption peak of N-H at 2150 cm -1 around disappears, indicating that the N atom in glycine participates in the coordination reaction, and the Zn-N stretching vibration absorption peak appears at 550 cm -1 around, indicating that glycine indeed chelates with zinc. And the infrared absorption spectrum of the zinc glycinate chelate in the national food safety standard GB19032-2015 Figure 1 .

[0030] The thermogravimetric chart of the zinc glycinate chelate prepared in the present example is shown in Figure 2 The thermogravimetric chart shows that the molecular formula of the product should be Zn(C2H5NO2)2.

[0031] Example 2

[0032] The present example provides a preparation method of food-grade zinc glycinate chelate, comprising the following steps:

[0033] (1) Synthesis reaction: Glycine 80 kg (1.07 kmol), zinc carbonate 70.3 kg (0.56 kmol), and mother liquor in Example 1 were put into a reaction kettle, water was added to the last reaction scale, the mixture was stirred and mixed, heated to 70°C, and reacted for 0.5 h to obtain a reaction solution;

[0034] (2) Purification and crystallization: the reaction solution was filtered while hot, then added to a crystallization kettle for cooling and crystallization, centrifuged, and the solid product was dried and sterilized to obtain zinc glycinate chelate product 111.2 kg, with a yield of 97.9%, and the product purity was 99.73% after detection, meeting the national standard.

[0035] Example 3

[0036] The example provides a preparation method of food-grade zinc glycinate chelate, comprising the following steps:

[0037] (1) Synthesis reaction: Glycine 150 kg (2 kmol), zinc hydroxide 104.4 kg (1.05 kmol), edible acetic acid 1.2 kg (0.02 kmol), and water 500 L were put into a reaction kettle, the mixture was stirred and mixed, heated to 85°C, and reacted for 1 h to obtain a reaction solution;

[0038] (2) Purification and crystallization: the reaction solution was filtered while hot, then added to a crystallization kettle for cooling and crystallization, centrifuged, and the solid product was dried and sterilized to obtain zinc glycinate chelate product 110.1 kg, with a yield of 51.7%, and the product purity was 99.86% after detection, meeting the national standard.

[0039] Example 4

[0040] The example provides a preparation method of food-grade zinc glycinate chelate, comprising the following steps:

[0041] (1) Synthesis reaction: Glycine 80 kg (1.07 kmol), zinc hydroxide 55.7 kg (0.56 kmol), and mother liquor in Example 3 were put into a reaction kettle, water was added to the last reaction scale, the mixture was stirred and mixed, heated to 85°C, and reacted for 1 h to obtain a reaction solution;

[0042] (2) Purification and crystallization: the reaction solution was filtered while hot, then added to a crystallization kettle for cooling and crystallization, centrifuged, and the solid product was dried and sterilized to obtain zinc glycinate chelate product 108.6 kg, with a yield of 95.6%, and the product purity was 99.79% after detection, meeting the national standard.

[0043] Example 5

[0044] The example provides a preparation method of food-grade zinc glycinate chelate, comprising the following steps:

[0045] (1) Synthesis reaction: Glycine 150 kg (2 kmol), zinc oxide 85.5 kg (1.05 kmol), edible acetic acid 3.6 kg (0.06 kmol) and water 550 L were put into a reaction kettle, stirred and mixed, heated to 90°C, and reacted for 2 h to obtain a reaction liquid;

[0046] (2) Purification and crystallization: the reaction liquid was filtered while hot, then added into a crystallization kettle for cooling and crystallization, centrifuged, and the solid product was dried and sterilized to obtain 114.5 kg of zinc glycinate chelate product, with a yield of 53.7%, and the product purity was 99.78%, meeting the national standard.

[0047] Example 6

[0048] The embodiment provides a preparation method of food-grade zinc glycinate chelate, comprising the following steps:

[0049] (1) Synthesis reaction: glycine 80 kg (1.07 kmol), zinc oxide 45.6 kg (0.56 kmol) and the mother liquor of Example 3 were put into a reaction kettle, water was added to the last reaction scale, stirred and mixed, heated to 90°C, and reacted for 2 h to obtain a reaction liquid;

[0050] (2) Purification and crystallization: the reaction liquid was filtered while hot, then added into a crystallization kettle for cooling and crystallization, centrifuged, and the solid product was dried and sterilized to obtain 112.9 kg of zinc glycinate chelate product, with a yield of 99.4%, and the product purity was 99.74%, meeting the national standard.

[0051] The above only describes the preferred embodiments of the present application and should not be used to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A process for the preparation of a food grade zinc glycinate chelate, characterized in that The method comprises the following steps: (1) a synthesis reaction: glycine 80 kg, zinc carbonate 70.3 kg and mother liquor are put into a reaction kettle, water is added to the last reaction scale, the mixture is stirred and mixed, heated to 70 DEG C, and the reaction is carried out for 0.5 h to obtain a reaction liquid; (2) purification and crystallization: the reaction liquid is filtered while hot, then added into a crystallization kettle to crystallize by cooling, centrifuged, and the solid product is dried and sterilized to obtain 111.2 kg of zinc glycine chelate product; The mother liquor is obtained by the following steps: a synthesis reaction: glycine 150 kg, zinc carbonate 131.7 kg, edible acetic acid 6 kg and water 400 L are put into a reaction kettle, the mixture is stirred and mixed, heated to 70 DEG C, and the reaction is carried out for 0.5 h to obtain a reaction liquid; and purification and crystallization: the reaction liquid is filtered while hot, then added into a crystallization kettle to crystallize by cooling, and the remaining solvent is obtained.

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