Processing method for improving processing performance of epsilon-polylysine
By adjusting pH in the charge modifier solution and sonicating the dextran nanoparticles/ε-polylysine complex, the problems of ε-polylysine flocculation and precipitation were solved, and its dispersion performance and antibacterial effect were improved, and simple and efficient processing improvement was achieved.
Patent Information
- Application Number
- CN202510938088.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-08-15
AI Technical Summary
ε-polylysine is prone to flocculation or precipitation during application, and the existing improvement methods are complex in operation and high in cost, which affects its processing performance and antibacterial effect.
The dextran nanoparticles and ε-polylysine were dispersed in the charge modifier solution, and the pH was adjusted to 7.5-9.0. The reaction was carried out under the ultrasonic field. After the reaction was completed, the dextran nanoparticles/ε-polylysine complex was prepared.
It significantly improves the dispersion performance of ε-polylysine in aqueous solution, and improves the antibacterial effect by 20-100 times. It has a wide range of application prospects, and is simple in process and high safety.
Smart Images
Figure CN120477238A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a processing method for improving the processing performance of epsilon-polylysine, and belongs to the technical field of food processing. Background Art
[0002] In recent years, with increasing consumer demand for greener and safer food, people are increasingly interested in new and highly effective preservatives. Currently, preservatives are primarily derived from two sources: chemical synthesis and natural sources. Chemically synthesized preservatives are relatively inexpensive and have a wide range of applications. However, synthetic preservatives can pose safety risks, such as neurotoxicity and cardiovascular damage, due to improper dosage. Naturally derived preservatives are typically extracted and purified from organisms such as microorganisms and plants, and are often safer and more nutritious.
[0003] As a natural, safe, and environmentally friendly biopreservative, ε-polylysine exhibits broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. However, ε-polylysine is highly hygroscopic, making it prone to flocculation or precipitation during application, producing a bitter taste and impacting the product's sensory quality.
[0004] Currently, methods to improve the hygroscopicity of polylysine and reduce flocculation or precipitation include cross-linking modification, preparation of micronized particles, and optimization of the preparation process. Cross-linking modification involves cross-linking hyaluronic acid or its salts with ε-polylysine or its salts in a neutral or alkaline environment, which can inhibit the protonation of polylysine and thus reduce flocculation and precipitation. Micronized particles can also be prepared by combining the ionic cross-linking of linear polysaccharide gum arabic with ε-polylysine and heat induction. This method not only improves the antibacterial ability of polylysine, but also significantly improves its hygroscopicity resistance and stability. Preparation process optimization is to improve the yield and quality of polylysine by optimizing the dissolved oxygen control strategy during the fermentation process of polylysine. However, these methods have problems such as complex operation, high cost, and limited application scenarios.
[0005] Therefore, there is an urgent need to develop a method that is simple in process and can comprehensively improve the processing properties of ε-polylysine. Summary of the Invention
[0006] [Technical Issues]
[0007] ε-polylysine itself has strong hygroscopicity, and is prone to flocculation or precipitation during application, and produces a bitter taste;
[0008] The methods for improving the hygroscopicity of polylysine and reducing flocculation or precipitation are complicated to operate, making it difficult to fully exert the antibacterial properties of ε-polylysine, thereby affecting its processing performance.
[0009] [Technical solution]
[0010] To address the above issues, the present invention provides a processing method for improving the processing performance of ε-polylysine. Specifically, the method disperses glucan nanoparticles and ε-polylysine in a charge modifier solution, adjusts the pH to 7.5-9.0, and reacts under an ultrasonic field. After the reaction, ultrafiltration and drying are performed to obtain a glucan nanoparticle / ε-polylysine complex. The glucan nanoparticle / ε-polylysine complex of the present invention can significantly improve the dispersion properties of ε-polylysine in aqueous solution, prevents flocculation, and exhibits excellent processing properties. It also exhibits excellent broad-spectrum antibacterial properties and has broad application prospects.
[0011] The first object of the present invention is to provide a processing method for improving the processing performance of ε-polylysine, comprising the following steps:
[0012] The dextran nanoparticles and ε-polylysine are dispersed in a charge modifier solution, the pH is adjusted to 7.5-9.0, and the solution is reacted under an ultrasonic field; after the reaction is completed, the solution is ultrafiltered and dried to obtain a dextran nanoparticle / ε-polylysine complex.
[0013] In one embodiment of the present invention, the source of glucan nanoparticles is endosperm of special grains such as rice, corn, sorghum, wheat, oats, and barley; the absolute molecular weight is 10 7 -10 8 Da, spherical diameter 60-100nm, molecular density 300-2000g / molnm 3 .
[0014] In one embodiment of the present invention, the mass ratio of dextran nanoparticles to ε-polylysine is 1:(0.3-0.5).
[0015] In one embodiment of the present invention, the charge modifier is one or more of chloroacetic acid, glucosamine, glucuronic acid, succinic anhydride, dimethylaminopropylamine, and aminoethylpiperazine; and the mass concentration of the charge modifier solution is 15-25%.
[0016] In one embodiment of the present invention, the mass concentration of the dextran nanoparticles in the charge modifier solution is 2-8%.
[0017] In one embodiment of the present invention, the pH is adjusted using a 0.1-2.0 M sodium hydroxide aqueous solution.
[0018] In one embodiment of the present invention, the reaction is carried out at 55-65° C. and an ultrasonic field power of 100-200 W for 4-8 hours.
[0019] In one embodiment of the present invention, the ultrafiltration is performed using a 100 kD ultrafiltration membrane.
[0020] In one embodiment of the present invention, the molecular weight of the dextran nanoparticle / ε-polylysine complex is 10 7 -10 8 Da, particle size 70-100nm, antibacterial MIC value is 20-100 times higher than that of original ε-polylysine.
[0021] In one embodiment of the present invention, the processing property is to improve the dispersibility of ε-polylysine in aqueous solution without flocculation.
[0022] In one embodiment of the present invention, the preparation method of dextran nanoparticles is as follows:
[0023] Cereal powder (100 mesh) was soaked in deionized water at 4°C for 8 hours (powder:water=1:5, stirred, and no precipitation was the standard); the liquid was centrifuged at 2000rpm for 30 minutes; filtered through a 100kD ceramic membrane, and the filtrate was then filtered through an 800D ultrafiltration membrane. Pure water was added to the filtrate after the first ultrafiltration to continue water washing and ultrafiltration; pure water was added every half hour for a total of 3 times. The retentate after ultrafiltration was spray dried, with the inlet temperature set at 170°C, the outlet temperature set at 75°C, and the feed rate set at 45mL / min. The spray-dried sample was added to deionized water at a ratio of 1:5 (w / v, g / 100mL), and the liquid was centrifuged at 6000rpm for 30 minutes to obtain glucan nanoparticles.
[0024] Furthermore, the grain powder is endosperm powder of special grains such as rice, corn, sorghum, wheat, oats, and barley.
[0025] The second object of the present invention is the dextran nanoparticle / ε-polylysine complex prepared by the method of the present invention.
[0026] The third object of the present invention is the application of the glucan nanoparticle / ε-polylysine complex of the present invention in the field of food processing.
[0027] The fourth object of the present invention is to provide a preservative, which uses the dextran nanoparticles / ε-polylysine complex of the present invention.
[0028] A fifth object of the present invention is to provide a method for preserving fruits and vegetables, meat products, dairy products and other foods, which uses the glucan nanoparticles / ε-polylysine complex of the present invention.
[0029] The sixth object of the present invention is to provide a method for improving the broad-spectrum antibacterial properties of ε-polylysine based on dextran nanoparticles, which uses the dextran nanoparticle / ε-polylysine complex described in the present invention.
[0030] [Beneficial Effects]
[0031] (1) The glucan nanoparticle / ε-polylysine complex prepared by the present invention has good antibacterial and antiseptic properties, and has antibacterial effects on Escherichia coli and Staphylococcus aureus, and the antibacterial MIC value is increased by 20-100 times compared with the original ε-polylysine; it has broad application prospects.
[0032] (2) The present invention adopts a one-step preparation method, which is simple, does not require the addition of toxic and harmful reagents, has low pollution and high safety.
[0033] (3) The glucan nanoparticles used in the present invention have a spherical structure and have a better antibacterial effect after being compounded with polylysine compared to high-amylose corn starch. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is an atomic force microscope image of dextran nanoparticles.
[0035] Figure 2 This is the HPLC chromatogram of the glucan nanoparticle / ε-polylysine complex in Example 1.
[0036] Figure 3 The figures are the inhibition zone test results of the embodiments and comparative examples.
[0037] Figure 4 These are the test results of the flocculation effect of ε-polylysine in Example 1 and Comparative Example 7. DETAILED DESCRIPTION
[0038] The following describes preferred embodiments of the present invention. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.
[0039] Test method:
[0040] 1. Broad-spectrum antibacterial performance test:
[0041] (1) Minimum inhibitory concentration: The minimum inhibitory concentration (MIC) was determined using the two-fold dilution method.
[0042] ε-polylysine and dextran nanoparticles / ε-polylysine complexes and other complexes were dissolved in a pH 7.0 buffer solution to form an antibacterial original solution with a concentration of 50 mg / mL. The solution was then diluted to two times the volume to form antibacterial solutions with different concentrations (0.012-25 mg / mL). Different sample solutions (50 uL) were added to a sterile 96-well plate, and an equal volume of LB liquid culture medium (the inoculation concentration was approximately 1×10 5CFU / mL) and then mix. Replace the antibacterial solution with the corresponding amount of pH buffer as a blank control. Place the 96-well plate containing the bacterial solution and antibacterial solution in a 37°C incubator at 200 rpm for 24 hours. Measure the absorbance at 600 nm. The MIC value is the concentration of the antibacterial substance in the wells that show no significant change and no visible turbidity.
[0043] (2) Inhibition zone diffusion test
[0044] Place three sterile filter paper sheets (Φ5 mm) evenly in each sterile Petri dish with a diameter of 70 mm. Then, pour about 15 mL of melted LB solid medium into the Petri dish, wait for the medium to solidify, and remove the sterile filter paper sheets. Add 50 μL of Escherichia coli (10 7 CFU / mL) and 50 μL of Staphylococcus aureus (10 6 Then, 50 μL of a 1 mg / mL, pH 7.0, antibacterial substance (ε-polylysine and dextran nanoparticles / ε-polylysine complex) solution was added to each well.
[0045] Buffer was added to the microwells as a control experiment. After covering the culture dish with a lid and sealing with parafilm, the plates were placed in a 4°C refrigerator for 2 hours for prediffusion, followed by incubation in a 37°C incubator for 24 hours. The diameter of the resulting inhibition zone was measured using the cross-hatch method. The plates were then placed in the 37°C incubator and the changes in the inhibition zone diameter were measured at regular intervals.
[0046] 2. Test whether ε-polylysine flocculates and precipitates:
[0047] After the ε-polylysine and dextran nanoparticle / ε-polylysine complex solution system was centrifuged at 6000 rpm, the appearance of the supernatant intuitively reflected the precipitation of ε-polylysine in the system.
[0048] The raw materials used in the embodiment are:
[0049] ε-Polylysine (absolute molecular weight 3000-5000 Da): Jiangsu Yiming Biotechnology Co., Ltd.;
[0050] The preparation method of dextran nanoparticles is as follows:
[0051] Special corn flour (100 mesh) was soaked in deionized water at 4°C for 8 hours (powder: water = 1:5, stirred, with no precipitation in water as the standard); the feed liquid was centrifuged at 2000rpm for 30 minutes using a centrifuge; filtered through a 100kD ceramic membrane, and the filtrate was then filtered through an 800D ultrafiltration membrane. Pure water was added to the filtrate after the first ultrafiltration to continue washing and ultrafiltration; pure water was added every half an hour for washing, and repeated 3 times. The retentate after ultrafiltration was spray-dried, with the inlet temperature set at 170°C, the outlet temperature at 75°C, and the feed rate at 45mL / min. After spray drying, glucan nanoparticles were obtained. The structure of glucan nanoparticles is as shown below. Figure 1 , spherical structure; absolute molecular weight 2.1×10 7 Da, diameter 76.9nm, molecular density 378.49g / mol nm 3 .
[0052] Example 1
[0053] A processing method for improving the processing performance of ε-polylysine comprises the following steps:
[0054] ε-polylysine and dextran nanoparticles were dispersed in a 20% chloroacetic acid aqueous solution at a mass ratio of 0.4:1. The pH was adjusted to 8.5 with a 1M sodium hydroxide aqueous solution. The reaction was maintained at 60°C and 200W for 6 hours. The mass concentration of the dextran nanoparticles in the chloroacetic acid aqueous solution was 5%.
[0055] After the reaction was completed, ultrafiltration was performed using a 100 kD ultrafiltration membrane; the retentate was vacuum freeze-dried for 48 h to obtain a dextran nanoparticle / ε-polylysine complex.
[0056] The obtained dextran nanoparticles / ε-polylysine complex was subjected to performance testing, and the test results are as follows:
[0057] Figure 2 : is the HPLC chromatogram of the glucan nanoparticles / ε-polylysine complex in Example 1. Figure 2 It can be seen that the complexation of dextran nanoparticles and ε-polylysine does not cause a change in the molecular weight of ε-polylysine.
[0058] Example 2
[0059] The mass ratio of glucan nanoparticles to ε-polylysine in Example 1 was adjusted to 1:0.3, and the other ratios were kept consistent with Example 1 to obtain a glucan nanoparticle / ε-polylysine complex.
[0060] Example 3
[0061] The mass ratio of glucan nanoparticles to ε-polylysine in Example 1 was adjusted to 1:0.5, and the other ratios were kept consistent with Example 1 to obtain a glucan nanoparticle / ε-polylysine complex.
[0062] Example 4
[0063] The pH 8.5 in Example 1 was adjusted to 8, and the other conditions remained the same as in Example 1 to obtain a dextran nanoparticle / ε-polylysine complex.
[0064] Example 5
[0065] The pH 8.5 in Example 1 was adjusted to 9, and the other conditions remained the same as in Example 1 to obtain a dextran nanoparticle / ε-polylysine complex.
[0066] Comparative Example 1
[0067] The glucan nanoparticles in Example 1 were adjusted to corn starch (item number S818265-1 kg, Maclean), and the other parameters were kept the same as in Example 1 to obtain a composite.
[0068] Comparative Example 2
[0069] The dextran nanoparticles in Example 1 were adjusted to carboxymethylated starch (degree of substitution 0.27 ± 0.01; M w 2×10 5 g / mol), and the rest were consistent with Example 1 to obtain a complex.
[0070] Comparative Example 3
[0071] The glucan nanoparticles in Example 1 were adjusted to carboxymethyl phytoglycogen, and the preparation method thereof was as follows:
[0072] The fresh kernels of su1 corn were shelled, the endosperm was separated from the germ, and soaked in 5 times its weight of deionized water at 20°C overnight; the softened corn was ground in a laboratory blender, passed through a 100-mesh sieve, and centrifuged at 600 rpm for 10 minutes. The supernatant was collected, and the precipitate was extracted twice with deionized water. The obtained decantate was heated in boiling water for 30 minutes to denature the protein. After centrifugation, 1 volume of the liquid was measured and 3 volumes of ethanol were added to precipitate the soluble carboxymethyl phytoglycogen. The precipitate was then collected and placed in a fume hood to remove residual ethanol. The dried solid was ground into powder to obtain phytoglycogen;
[0073] Other steps were the same as in Example 1 to obtain a composite.
[0074] Comparative Example 4
[0075] A processing method for improving the processing performance of ε-polylysine comprises the following steps:
[0076] (1) 40 g of dextran nanoparticles were dissolved in 250 mL of 85% ethanol aqueous solution, stirred at 40°C and 200 rpm for 30 min, 40 mL of 25% NaOH aqueous solution was added to activate the hydroxyl groups, stirred at 40°C and 200 rpm for 90 min, and then 60 mL of 19.5% chloroacetic acid aqueous solution was added to carry out substitution reaction, and stirred at 40°C and 200 rpm for 5 h; after the reaction was completed, the reaction solution was removed by suction to obtain a filter cake; the filter cake was dispersed in 200 mL of water, the pH was adjusted to 7, and then anhydrous ethanol was added, and the mixture was allowed to stand at 4°C for 2 h, filtered, washed, and dried to obtain modified dextran nanoparticles;
[0077] (2) Dispersing the modified dextran nanoparticles and ε-polylysine in water, respectively, to form a modified dextran nanoparticle solution and an ε-polylysine solution; then, adding the ε-polylysine solution dropwise into the modified dextran nanoparticle solution and mixing them uniformly to obtain a solution; the mass concentration of the modified dextran nanoparticles in the solution is 5%;
[0078] (3) The solution was centrifuged at 5000 rpm for 10 min, and the supernatant was freeze-dried in vacuo for 48 h to obtain a dextran nanoparticle / ε-polylysine complex.
[0079] Comparative Example 5
[0080] The adjustment of pH to 8.5 in Example 1 was omitted, and other procedures remained the same as in Example 1 to obtain a dextran nanoparticle / ε-polylysine complex.
[0081] Comparative Example 6
[0082] Only dextran nanoparticles were used.
[0083] Comparative Example 7
[0084] Only ε-polylysine was used.
[0085] Comparative Example 8
[0086] The ultrasonic treatment in Example 1 was omitted, and the other steps were the same as in Example 1 to obtain a dextran nanoparticle / ε-polylysine complex.
[0087] The obtained composite was subjected to performance testing, and the test results are as follows:
[0088] Table 1
[0089]
[0090] Figure 4 The flocculation effect test results of ε-polylysine in Example 1 and Comparative Example 7 are shown in FIG. Figure 4It can be seen that: when only ε-polylysine is used, flocculation is easy; but when the composite of the present invention is used, basically no flocculation occurs.
[0091] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.
Claims
1. A processing method for improving the processing performance of ε-polylysine, characterized in that: The steps include: The dextran nanoparticles and ε-polylysine are dispersed in a charge modifier solution, the pH is adjusted to 7.5-9.0, and the solution is reacted under an ultrasonic field; after the reaction is completed, the solution is ultrafiltered and dried to obtain a dextran nanoparticle / ε-polylysine complex.
2. The method according to claim 1, characterized in that The mass ratio of dextran nanoparticles to epsilon-polylysine is 1:(0.3-0.5); and the mass concentration of dextran nanoparticles in the charge modifier solution is 2-8%.
3. The method according to claim 1, characterized in that The source of glucan nanoparticles is the endosperm of special grains such as rice, corn, sorghum, wheat, oats, and barley; the absolute molecular weight is 10 7 -10 8 Da, spherical diameter 60-100nm, molecular density 300-2000g / mol nm 3 .
4. The method according to claim 1, wherein The reaction is carried out under an ultrasonic field at 55-65°C and an ultrasonic field power of 100-200W for 4-8 hours.
5. The method according to claim 1, wherein The mass concentration of the charge modifier solution is 15-25%.
6. A dextran nanoparticle / ε-polylysine complex prepared by the method according to any one of claims 1 to 5.
7. Use of the glucan nanoparticle / ε-polylysine complex according to claim 6 in the field of food processing.
8. A preservative, characterized in that The dextran nanoparticle / ε-polylysine complex according to claim 6 is used.
9. A method for preserving fruits, vegetables, meat products, dairy products and other foods, characterized in that: The dextran nanoparticle / ε-polylysine complex according to claim 6 is used.
10. A method for improving the broad-spectrum antibacterial properties of ε-polylysine based on dextran nanoparticles, characterized in that: The dextran nanoparticle / ε-polylysine complex according to claim 6 is used.