Preparation method and application of lysine-polyacid-polyol copolymer

Abstract

The invention discloses a preparation method and application of a lysine-polyacid-polyol copolymer. According to the lysine-polyacid-polyol copolymer, three compounds including lysine, polyacid and polyol react for a long time to form a high polymer. The lysine-polyatomic acid-polyol copolymer prepared by the method has good water solubility and efficient antibacterial performance, the good water solubility can greatly improve the bactericidal performance of the lysine-polyatomic acid-polyol copolymer, the synthesis process is green and environment-friendly, safe and non-toxic, and the preparation process is simple.

Description

Technical Field

[0001] The present invention belongs to the field of food antibacterial agents, and specifically relates to a preparation method and application of a lysine-polyacid-polyol copolymer. Background Art

[0002] Lysine is an alkaline amino acid with two amino groups in its structure. Amino groups are good cationic functional groups, but single lysine does not have antibacterial activity. Most of the current research produces antibacterial activity by grafting its own condensation products, and polylysine is difficult to prepare. The lysine-glycerol copolymer disclosed in this patent has a simple preparation method, and because it carries cationic static electricity, it can be adsorbed to the cell membrane surface of microorganisms, and after combining with the cell membrane, it forms holes in the membrane, causing leakage of cell contents and destroying the normal physiological metabolism of microorganisms. Lysine is allowed to be used in the national additive standards.

[0003] Polyol refers to an organic compound containing multiple hydroxyl groups (-OH) in the molecule. The different number of hydroxyl groups makes the types of polyols diverse. Common polyols include ethylene glycol (containing two hydroxyl groups), glycerol (containing three hydroxyl groups) and sorbitol (containing six hydroxyl groups). Polyols are important raw materials and pharmaceutical preparations for the synthesis of polyesters and polyurethanes, providing moisture retention and stability. Polyols have good solubility, lubricity and moisture retention due to their multi-hydroxy structure and are widely used in various industries. Polyacids refer to organic compounds containing multiple carboxyl groups (-COOH) in the molecule. According to the number of carboxyl groups, polyacids can be divided into dibasic acids, tribasic acids and more polyacids. Dibasic acids are the most common types, such as oxalic acid (containing two carboxyl groups) and phthalic acid (containing two carboxyl groups). Polyacids are key raw materials for the synthesis of polymers (such as polyesters and polyurethanes) and are used to manufacture plastics, coatings, fibers and other products. Some polyacids such as succinic acid, adipic acid, fumaric acid, etc. are used as food additives to adjust the acidity and flavor of food. Due to their chemical activity, polyacids are widely used in polymer synthesis, food seasoning, industrial manufacturing, etc.

[0004] Lysine-polyacid-polyol copolymer is a general term for polymers of different molecular weights formed by condensation reaction of lysine, polyacid and polyol in the presence of a catalyst, and removal of a molecule of water to form an ester group. Depending on the time of the heating reaction, different fragments of lysine-glycerol copolymer can be obtained. This substance contains a large number of amino functional groups and has very good water solubility. Under acidic conditions, it can form a large number of amino cations. This compound has very strong antibacterial activity.

[0005] At present, the antibacterial active agents on the market with lysine as the antibacterial monomer are basically based on polylysine as the precursor, and various compounds are grafted by modifying polylysine. This type of antibacterial grafting has great limitations, and the synthesis of the precursor polylysine is very difficult. Polylysine needs to reach a polymerization of greater than or equal to 10 to have antibacterial activity, which leads to high cost of antibacterial preparations, difficult preparation, great environmental pollution, and low synthesis yield of such compounds. However, no institution has yet developed a product with lysine as the basic unit and high efficiency antibacterial activity. Summary of the invention

[0006] The purpose of the present invention is to provide a preparation method and application of a lysine-polyacid-polyol copolymer to solve the problems and shortcomings of the above-mentioned technology. The preparation method is in line with the green chemistry concept advocated by the country. The method has the advantages of low cost, high preparation efficiency, high antibacterial activity, simple operation, etc.

[0007] To achieve the above purpose, this patent provides the following solutions:

[0008] The preparation method and application of lysine-polyacid-polyol copolymer are characterized in that the preparation method is as follows:

[0009] (1) By weight, 20-50 parts of polyol and 30-80 parts of lysine are mixed uniformly, and 1-3 parts of sodium carbonate are added at 80-150° C. and stirred for reaction for 1-8 hours to obtain copolymer 1;

[0010] (2) adding 15-30 parts of polyacid to copolymer 1, mixing evenly and heating to 80-150° C., stirring and reacting for 1-8 hours after the polyacid is completely dissolved, further slowly adding 10-20 parts of lysine, mixing evenly, raising the temperature to 80-150° C., and continuing the reaction for 1-8 hours to obtain copolymer 2;

[0011] (3) adding 4-10 parts of polyacid and 10-20 parts of lysine to copolymer 2 and repeating step (2) to obtain copolymer 3, washing with anhydrous ethanol for multiple times, drying, and crushing to obtain a finished product of lysine-polyacid-polyol copolymer;

[0012] The preparation method and application of a lysine-polyacid-polyol copolymer are characterized in that the inhibited microorganisms are Staphylococcus aureus, Escherichia coli, Aspergillus niger and Aspergillus flavus.

[0013] The preparation method and application of lysine-polyacid-polyol copolymer are characterized in that the polyacid is one or more of succinic acid, tartaric acid, maleic acid, and citric acid, and the polyol is one or more of glycerol, polymerized glycerol (polymerization degree 2-20), sorbitol, xylitol, glucose, and sucrose.

[0014] As a further improvement of the technical solution of the preparation method of the present invention, preferably, in the preparation method and application of the lysine-polyacid-polyol copolymer, the time for the heating reaction of the polyol and lysine in step (1) is 1-8 hours, preferably 4 hours.

[0015] As a further improvement of the technical solution of the preparation method of the present invention, preferably, in the preparation method and application of the lysine-polyacid-polyol copolymer, in step (2), the continuous heating time of the copolymer 1 is 1-8 hours, preferably 4 hours. DETAILED DESCRIPTION

[0016] The present invention will be further explained below in conjunction with specific examples. It should be understood that these examples are preferred embodiments of the present invention and are only used for specific description.

[0017] Example 1

[0018] (1) 10 g of glycerol and 15 g of lysine were placed in a reaction container, ultrasonically dispersed for 5 min to make them uniformly mixed, 0.5 g of sodium carbonate was added, the reactants were heated and stirred at 125° C. for 4 h, and the reaction container was naturally cooled to evaporate the water, thereby obtaining polymer 1;

[0019] (2) Add 7.5 g of citric acid to polymer 1 and mix well, stir and heat to 85° C., wait until the citric acid is completely dissolved, react for 1 h, further slowly add 7.5 g of lysine and mix well, increase the reaction temperature to 125° C., continue the reaction for 2 h, and cool the reaction container naturally to evaporate the water, thereby obtaining polymer 2;

[0020] (3) Add 2 g of citric acid to polymer 2 and mix evenly. Stir and heat to 85° C. until the citric acid is completely dissolved and react for 1 h. Then slowly add 7.5 g of lysine and mix evenly. Raise the reaction temperature to 125° C. and continue the reaction for 2 h. Naturally cool the reaction vessel to evaporate the water to obtain polymer 3. Rinse polymer 3 three times with anhydrous ethanol and dry in an oven for 3 h. Use a grinder to grind the dried polymer 3 to obtain a lysine-citric acid-citric acid-glycerol copolymer.

[0021] Example 2

[0022] (1) 12 g of sorbitol and 13 g of lysine were placed in a reaction container, ultrasonically dispersed for 5 min to uniformly mix, 0.5 g of sodium carbonate was added, the reactants were heated and stirred at 125° C. for 2 h, and the reaction container was naturally cooled to evaporate the water, thereby obtaining polymer 1;

[0023] (2) Add 7.5 g of maleic acid to polymer 1 and mix well, stir and heat to 85° C., wait until the maleic acid is completely dissolved, react for 1 h, then slowly add 7.5 g of lysine and mix well, raise the reaction temperature to 125° C., continue the reaction for 4 h, and cool the reaction container naturally to evaporate the water, thereby obtaining polymer 2;

[0024] (3) Add 2 g of maleic acid to polymer 2 and mix evenly. Stir and heat to 85° C. until the maleic acid is completely dissolved and react for 1 h. Then slowly add 7.5 g of lysine and mix evenly. Raise the reaction temperature to 125° C. and continue the reaction for 4 h. Naturally cool the reaction vessel to evaporate the water to obtain polymer 3. Rinse polymer 3 three times with anhydrous ethanol and dry in an oven for 3 h. Use a grinder to grind the dried polymer 3 to obtain an antibacterial lysine-maleic acid-sorbitol copolymer.

[0025] Example 3

[0026] (1) 10 g of polyglycerol and 15 g of lysine were placed in a reaction container, ultrasonically dispersed for 5 min to make them uniformly mixed, 0.5 g of sodium carbonate was added, the reactants were heated and stirred at 125° C. for 5 h, and the reaction container was naturally cooled to evaporate the water, thereby obtaining polymer 1;

[0027] (2) Add 8 g of tartaric acid to polymer 1 and mix well, stir and heat to 85° C., wait until the tartaric acid is completely dissolved, react for 1 h, then slowly add 7 g of lysine and mix well, raise the reaction temperature to 125° C., continue the reaction for 3 h, and cool the reaction container naturally to evaporate the water, thereby obtaining polymer 2;

[0028] (3) Add 2 g of tartaric acid to polymer 2 and mix evenly. Stir and heat to 85°C until the tartaric acid is completely dissolved and react for 1 hour. Then slowly add 7.5 g of lysine and mix evenly. Raise the reaction temperature to 125°C and continue the reaction for 3 hours. Naturally cool the reaction vessel to evaporate the water to obtain polymer 3. Rinse polymer 3 three times with anhydrous ethanol and dry in an oven for 3 hours. Use a grinder to grind the dried polymer 3 to obtain an antibacterial lysine-tartaric acid-polyglycerol copolymer.

[0029] Example 4

[0030] (1) 10 g of glucose and 15 g of lysine were placed in a reaction container, ultrasonically dispersed for 5 min to make them uniformly mixed, 0.5 g of sodium carbonate was added, the reactants were heated and stirred at 125° C. for 2.5 h, and the reaction container was naturally cooled to evaporate the water, thereby obtaining polymer 1;

[0031] (2) Add 7.5 g of succinic acid to polymer 1 and mix well, stir and heat to 85° C., wait until the succinic acid is completely dissolved, react for 1 h, then slowly add 7.5 g of lysine and mix well, raise the reaction temperature to 125° C., continue the reaction for 5 h, and cool the reaction container naturally to evaporate the water, thereby obtaining polymer 2;

[0032] (3) Add 2 g of succinic acid to polymer 2 and mix evenly. Stir and heat to 85°C until succinic acid is completely dissolved and react for 1 h. Then slowly add 7.5 g of lysine and mix evenly. Raise the reaction temperature to 125°C and continue the reaction for 5 h. Naturally cool the reaction vessel to evaporate the water to obtain polymer 3. Rinse polymer 3 three times with anhydrous ethanol and dry in an oven for 3 h. Grind the dried polymer 3 with a grinder to obtain an antibacterial lysine-succinic acid-polyvinyl alcohol copolymer.

[0033] Example 5

[0034] (1) 10 g of xylitol and 15 g of lysine were placed in a reaction container, ultrasonically dispersed for 5 min to make them uniformly mixed, 0.5 g of sodium carbonate was added, the reactants were heated and stirred at 125° C. for 3.5 h, and the reaction container was naturally cooled to evaporate the water, thereby obtaining polymer 1;

[0035] (2) Add 7.5 g of maleic acid to polymer 1 and mix well, stir and heat to 85° C., wait until the maleic acid is completely dissolved, react for 1 hour, then slowly add 7.5 g of lysine and mix well, raise the reaction temperature to 125° C., continue the reaction for 3.5 hours, and naturally cool the reaction container to evaporate the water, thereby obtaining polymer 2;

[0036] (3) Add 2 g of maleic acid to polymer 2 and mix evenly. Stir and heat to 85°C until the maleic acid is completely dissolved and react for 1 hour. Then slowly add 7.5 g of lysine and mix evenly. Raise the reaction temperature to 125°C and continue the reaction for 3.5 hours. Naturally cool the reaction vessel to evaporate the water to obtain polymer 3. Rinse polymer 3 three times with anhydrous ethanol and dry in an oven for 3 hours. Use a grinder to grind the dried polymer 3 to obtain an antibacterial lysine-maleic acid-xylitol copolymer.

[0037] Antibacterial experiment

[0038] Preparation of the drug solution of each example: 4 g of the lysine-polyacid-polyol copolymer prepared in each example was fully dissolved in 10 mL of deionized water for later use.

[0039] Preparation of ε-polylysine solution: Dissolve 4 g of ε-polylysine in 10 mL of deionized water for later use.

[0040] Preparation of α-polylysine solution: Dissolve 4 g of α-polylysine in 10 mL of deionized water for later use.

[0041] Preparation of chitosan hydrochloride solution: Dissolve 4 g of chitosan hydrochloride in 10 mL of deionized water for later use.

[0042] Preparation of tea polyphenols solution: fully dissolve 4 g of tea polyphenols in 10 mL of deionized water for later use.

[0043] 1. Antibacterial test of Staphylococcus aureus

[0044] Evenly spread 120 μL of the McFarland concentration Staphylococcus aureus bacterial solution diluted 1000 times onto the prepared agar plate and let it stand until the bacterial solution is absorbed.

[0045] Place 10 pieces of filter paper in a glass plate; shake the sample vigorously, quickly take a sample of 10 μL and drop it on the filter paper, then use sterile tweezers to stick the filter paper on the agar surface coated with the bacterial solution, gently press the filter paper to make it properly contact with the agar, stick three pieces of paper on each plate, parallel to the three plates, and make the spacing between the pieces of paper equal. Then, observe the inhibition zone after incubating in a 37℃ incubator for 24 hours, and then use a vernier caliper to measure the diameter of each inhibition zone, and take the average value and count.

[0046] 2. Antibacterial test of Escherichia coli

[0047] Evenly spread 120 μL of the 1000-fold diluted Escherichia coli bacterial solution on the prepared agar plate and let it stand until the bacterial solution is absorbed.

[0048] Place 10 pieces of filter paper in a glass plate; shake the sample vigorously, quickly take a sample of 10 μL and drop it on the filter paper, then use sterile tweezers to stick the filter paper on the agar surface coated with the bacterial solution, gently press the filter paper to make it properly contact with the agar, stick three pieces of paper on each plate, parallel to the three plates, and make the spacing between the pieces of paper equal. Then, observe the inhibition zone after incubating in a 37℃ incubator for 24 hours, and then use a vernier caliper to measure the diameter of each inhibition zone, and take the average value and count.

[0049] 3. Antibacterial test of Aspergillus niger:

[0050] 120 μL of the Aspergillus niger bacterial solution diluted 1000 times was evenly spread on the prepared agar plate and allowed to stand until the bacterial solution was absorbed.

[0051] Place 10 pieces of filter paper in a glass plate; shake the sample vigorously, quickly take a sample of 10 μL and drop it on the filter paper, then use sterile tweezers to stick the filter paper on the agar surface coated with the bacterial solution, gently press the filter paper to make it properly contact with the agar, stick three pieces of paper on each plate, parallel to the three plates, and make the spacing between the pieces of paper equal. Then, observe the inhibition zone after incubating in a 37℃ incubator for 24 hours, and then use a vernier caliper to measure the diameter of each inhibition zone, and take the average value and count.

[0052] 4. Antibacterial test of Aspergillus flavus:

[0053] Evenly spread 120 μL of the 1000-fold diluted Aspergillus flavus liquid on the prepared agar plate and let it stand until the liquid is absorbed.

[0054] Place 10 pieces of filter paper in a glass plate; shake the sample vigorously, quickly take a sample of 10 μL and drop it on the filter paper, then use sterile tweezers to stick the filter paper on the agar surface coated with the bacterial solution, gently press the filter paper to make it properly contact with the agar, stick three pieces of paper on each plate, parallel to the three plates, and make the spacing between the pieces of paper equal. Then, observe the inhibition zone after incubating in a 37℃ incubator for 24 hours, and then use a vernier caliper to measure the diameter of each inhibition zone, and take the average value and count.

[0055] Table 1 Inhibition zone of Examples 1-5

[0056]

[0057] Table 1 shows the inhibitory effect of lysine-polyacid-polyol copolymer on four bacteria, in which the inhibitory strengths on the four bacteria are Escherichia coli > Aspergillus niger > Staphylococcus aureus > Aspergillus flavus.

[0058] Table 2 Inhibition zone of control drugs

[0059]

[0060]

[0061] According to Table 2, the antibacterial effect of the lysine-polyacid-polyol copolymer prepared in Examples 1-5 is better than that of chitosan hydrochloride and tea polyphenols, and is slightly stronger than polylysine against Aspergillus flavus and Aspergillus niger. The overall antibacterial effect is similar to that of the two polylysines.

[0062] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. Preparation method and application of lysine-polyacid-polyol copolymer, characterized in that The following preparation method: (1) By weight, 20-50 parts of polyol and 30-80 parts of lysine are mixed uniformly, and 1-3 parts of sodium carbonate are added at 80-150° C. and stirred for reaction for 1-8 hours to obtain copolymer 1; (2) Add 15-30 parts of polyacid to copolymer 1, mix evenly and heat to 80-150° C., after the polyacid is completely dissolved, stir and react for 1-8 hours, further slowly add 10-20 parts of lysine and mix evenly, raise the temperature to 80-150° C., and continue to react for 1-8 hours to obtain copolymer 2; (3) adding 4-10 parts of polyacid and 10-20 parts of lysine to copolymer 2 and repeating step (2) to obtain copolymer 3, washing with anhydrous ethanol for multiple times, drying, and crushing to obtain a finished lysine-polyacid-polyol copolymer; The copolymer is used for inhibiting microorganisms in food.

2. The preparation method according to claim 1, wherein the polyacid comprises one or more of succinic acid, tartaric acid, maleic acid, and citric acid, and the polyol comprises one or more of glycerol, polyglycerol (degree of polymerization 2-20), sorbitol, xylitol, glucose, and sucrose.

3. The preparation method according to claim 1, characterized in that: The heating reaction time of the polyol and lysine in step (1) is 1-8 hours.

4. The preparation method according to claim 1, characterized in that: In step (2), the continuous heating time of copolymer 1 is 1-8 hours.

5. The microorganism according to claim 1, characterized in that: Staphylococcus aureus, Escherichia coli, Aspergillus niger, Aspergillus flavus.

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