阅读说明：本技术 一种乳酸链球菌素复合物及其在制备抗菌剂中的应用 (Nisin compound and application thereof in preparation of antibacterial agent ) 是由 钱俊青 李新晨 于 2021-01-22 设计创作，主要内容包括：本发明公开了一种乳酸链球菌素复合物及其在制备抗菌剂中的应用,所述复合物是由乳酸链球菌素与单甘酯以质量比1:0.1-5制成；所述单甘酯包括单硬脂酸甘油酯、单棕榈酸甘油酯、单油酸甘油酯。本发明将单甘酯与Nisin在水中复合,得到两种物质的复合物,可保持高食品安全性。通过复合,可明显提高抑菌效果,对试验的革兰氏阳性菌种金黄色葡萄球菌,复合物的抑菌效果较同样量的Nisin提高50％以上,对试验的革兰氏阴性菌种大肠杆菌,复合物的抑菌效果较同样量的Nisin提高30％以上。单甘酯是低成本的食品原料,复合物也提升了经济效益。(The invention discloses a nisin compound and application thereof in preparing an antibacterial agent, wherein the nisin compound is prepared from nisin and monoglyceride in a mass ratio of 1: 0.1-5; the monoglyceride includes glyceryl monostearate, glyceryl monopalmitate, and glyceryl monooleate. The monoglyceride and Nisin are compounded in water to obtain the compound of the two substances, so that high food safety can be maintained. By compounding, the antibacterial effect can be obviously improved, and the antibacterial effect of the compound on a tested gram-positive strain staphylococcus aureus is improved by more than 50% compared with the antibacterial effect of Nisin with the same amount, and the antibacterial effect of the compound on a tested gram-negative strain escherichia coli is improved by more than 30% compared with the antibacterial effect of Nisin with the same amount. Monoglyceride is a low-cost food material, and the compound also improves economic benefits.)

1. A nisin complex is characterized in that the complex is prepared from nisin and monoglyceride in a mass ratio of 1: 0.1-5; the monoglyceride includes glyceryl monostearate, glyceryl monopalmitate, and glyceryl monooleate.

2. The nisin complex according to claim 1, wherein the nisin complex is prepared from nisin and monoglyceride in a mass ratio of 1: 0.1-3.

3. Nisin complex according to claim 1 wherein said nisin complex is prepared according to the following process: dissolving nisin powder in deionized water, adding monoglyceride, stirring for dissolving, adjusting the pH value to 4-8, performing ultrasonic dispersion, keeping the temperature at 15-35 ℃, stirring for 60-90 minutes, then performing reduced pressure concentration to remove 80% of water, and drying to obtain the nisin compound.

4. The nisin complex according to claim 3, wherein the ultrasonic dispersion is carried out at a power of 600W for 4 to 6 minutes.

5. The nisin complex according to claim 3, wherein the conditions for removing water are: 80% of the water was evaporated in a rotary evaporator at 60 ℃ under a vacuum of 0.1 atm.

6. Nisin complex according to claim 3 characterized in that the drying is a vacuum drying at 0.1 atmosphere at 50 ℃.

7. A nisin complex according to claim 3 wherein the nisin is present in a mass ratio to monoglyceride of 1:0.1 to 5; the volume dosage of the deionized water is 10-100ml/g calculated by the weight of nisin.

8. Use of the nisin complex of claim 1 for the preparation of a bacteriostatic agent.

9. The use according to claim 8, wherein the bacteriostatic agent is a bacteriostatic agent for staphylococcus aureus or escherichia coli.

(I) technical field

The invention relates to an antibacterial agent, in particular to a nisin compound and application thereof in preparing an antibacterial agent.

(II) background of the invention

Nisin (Nisin) has been approved for use as a highly safe food preservative in many countries around the world. The Nisin has higher safety and better antibacterial effect than other food preservatives, thereby having ideal application prospect. In order to improve the antibacterial effect of Nisin, scientific and technical personnel at home and abroad develop a lot of exploration, but no ideal effective method for improving the antibacterial effect of Nisin is obtained. The invention adopts the compounding of monoglyceride and Nisin, and the antibacterial effect of the compound on gram-positive bacteria and gram-negative bacteria is improved compared with that of Nisin. Monoglyceride is a food raw material, and the food safety is not influenced by the combination of monoglyceride and Nisin, so that the monoglyceride has good application.

Disclosure of the invention

The invention aims to provide a Nisin-monoglyceride compound and application thereof in preparation of a bacteriostatic agent, which can obviously improve the bacteriostatic effect, enhance the antibacterial property of Nisin, improve the dispersibility of Nisin in lipid food and solve the problem that Nisin is easy to agglomerate when applied in lipid food.

The technical scheme adopted by the invention is as follows:

the invention provides a nisin complex, which is prepared from nisin and monoglyceride in a mass ratio of 1: 0.1-5; the monoglyceride includes glyceryl monostearate, glyceryl monopalmitate, and glyceryl monooleate.

Further, the nisin complex is prepared from nisin and monoglyceride in a mass ratio of 1: 0.1-3.

The nisin complex of the invention is prepared by the following method: dissolving Nisin (Nisin) powder in deionized water, adding monoglyceride, stirring for dissolving, and adjusting pH to 4-8 (preferably 0.05 mol. L)^-1Aqueous HCl solution or 0.05 mol. L^-1Aqueous solution blending of NaOH), ultrasonic dispersion (preferably 600W power ultrasonic for 4-6 minutes), heat preservation and stirring at 15-35 ℃ for 60-90 minutes to promote mutual compounding of Nisin and monoglyceride, then reduced pressure concentration is carried out to remove 80% of water (preferably 80% of water is evaporated at 60 ℃ in a rotary evaporator with 0.1 atmospheric vacuum degree), and drying (preferably 0.1 atmospheric 50 ℃ vacuum drying is carried out until the water content is lower than 10%) is carried out to obtain the Nisin compound.

Further, the mass ratio of the nisin to the monoglyceride is 1: 0.1-5; the volume dosage of the deionized water is 10-100ml/g, preferably 15-25ml/g calculated by the weight of nisin.

The invention also provides an application of the nisin compound in preparing a bacteriostatic agent, wherein the bacteriostatic agent is a bacteriostatic agent of Staphylococcus aureus (Staphylococcus aureus) or Escherichia coli (Escherichia coli).

Compared with the prior art, the invention has the following beneficial effects: the monoglyceride and Nisin are compounded in water to obtain the compound of the two substances, so that high food safety can be maintained. By compounding, the antibacterial effect can be obviously improved, and the antibacterial effect of the compound on a tested gram-positive strain staphylococcus aureus is improved by more than 50% compared with the antibacterial effect of Nisin with the same amount, and the antibacterial effect of the compound on a tested gram-negative strain escherichia coli is improved by more than 30% compared with the antibacterial effect of Nisin with the same amount. Monoglyceride is a low-cost food material, and the compound also improves economic benefits.

(IV) description of the drawings

FIG. 1 is a 200-nm 250-nm UV scan of an aqueous solution of nisin in example 1.

FIG. 2 is a 200-nm 250-nm UV scan of an aqueous solution of nisin complex in example 1.

(V) detailed description of the preferred embodiments

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto:

example 1:

1. nisin complexes

Weighing 2.0 g Nisin (purity 90%) produced by Tianjin Kangsheng Probiotics, Inc., adding 150mL deionized water, stirring for dissolving, adding 8.0 g glyceryl monostearate (Weifang Shengbaolong, produced by Biotech, Inc.), and adding 0.05 mol.L^-1Adjusting pH to 5.0 with HCl aqueous solution, placing the solution in an ultrasonic instrument for 5 minutes by ultrasonic treatment with 600W power, mechanically stirring the solution at 25 ℃ for 60 minutes while keeping the temperature, rotationally evaporating 120mL of water at 60 ℃ under 0.1 atmospheric pressure in a vacuum degree, and then drying the solution at 50 ℃ under 0.1 atmospheric pressure in a vacuum degree to obtain 9.8 g of nisin complex with the water content of 8.6%.

Respectively dissolving nisin complex and nisin in deionized water to prepare a mass concentration of 0.1%, taking the deionized water as a reference, and performing absorption scanning at a wavelength of 200-250nm of an ultraviolet spectrophotometer (figures 1 and 2), wherein a scanning curve of the nisin aqueous solution (figure 1) shows that an absorption peak exists at 222nm, and a scanning curve of the nisin complex aqueous solution (figure 2) shows that three absorption peaks exist at 222nm, 224nm and 226 nm. Indicating that the nisin is compounded with the monoglyceride to cause the change of ultraviolet light absorption.

2. Bacteriostasis test

Test strains: respectively inoculating Staphylococcus aureus (Staphylococcus aureus) (China center for Industrial microorganism culture Collection, number 10001) and Escherichia coli (Escherichia coli) (China center for Industrial microorganism culture Collection, number 10003) into 250mL Erlenmeyer flask containing nutrient agar medium (produced by Hangzhou microbial agent Co., Ltd.), shake-culturing at 30 deg.C and 200rpm/min for 15h, and adjusting cell number of culture solution to 4.5 × 10 with deionized water sterilized at 121 deg.C⁶CFU/mL was used as the test bacterial liquid.

And (3) compound sterilization test: 2.0 g of nisin complex prepared in step 1 was dissolved in 40mL of deionized water as a sterilizing solution. 0.2mL of the bactericidal solution was uniformly mixed with 9.8mL of the test bacterial solution, the pH was adjusted to 5.5, 0.1mL of the mixture was taken out and spread on nutrient agar plates (produced by Hangzhou microbial reagents, Ltd.), 3 plates were applied to each bactericidal solution, and the mixture was inverted and placed in a constant temperature incubator to be cultured at 30 ℃ for 24 hours. And observing and recording the colony number of each plate, and taking an average value of the colony numbers of the plates.

Nisin controls: nisin 0.4 g is used to replace Nisin complex, and other operations are the same as the complex sterilization test.

Monoglyceride control: 1.6 g of glyceryl monostearate is weighed to replace the nisin complex, and other operations are the same as the complex sterilization test.

Blank control: adding 0.2mL of deionized water into 9.8mL of test bacterium liquid, mixing, adjusting the pH value to 5.5, taking 0.1mL of the mixed solution, coating the mixed solution on a nutrient agar plate, uniformly coating the nutrient agar plate, and performing inverted culture in an incubator at constant temperature of 30 ℃ for 24 hours. And observing and recording the colony number of each plate, and taking an average value of the colony numbers of the plates.

And calculating the sterilization rate of the compound and the comparison according to a sterilization rate formula:

bactericidal rate ═ 100% (number of colonies of blank control-number of colonies of bactericidal)/number of colonies of blank control

The sterilization rate of glyceryl monostearate is subtracted from the sterilization rate of the compound obtained by the test, and then the sterilization rate is compared with the sterilization rate of Nisin, and the calculation method comprises the following steps: the improvement rate is (compound sterilization rate-glyceryl monostearate sterilization rate-Nisin sterilization rate)/Nisin sterilization rate is 100%.

Staphylococcus aureus bactericidal rate: the sterilization rate of the composite staphylococcus aureus is 53.4%, the sterilization rate of the glyceryl monostearate staphylococcus aureus is 4.1%, the sterilization rate of the Nisin staphylococcus aureus is 30.9%, and the sterilization rate of the composite staphylococcus aureus is improved by 59.4% by calculation.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 28.7%, the glyceryl monostearate escherichia coli sterilization rate is 1.5%, the Nisin escherichia coli sterilization rate is 19.8%, and the compound escherichia coli sterilization rate is improved by 37.4% through calculation.

Example 2:

1. nisin complexes

Weighing 9.0 g Nisin (purity 80%) produced by Zhengzhou Chengxingwang chemical food additive Co., Ltd, adding into 150mL deionized water, stirring for dissolving, adding 1.0 g glyceryl monostearate (Weifang Shengbaolong Biotech Co., Ltd.), and dissolving with 0.05 mol.L^-1Adjusting the pH value of the HCl aqueous solution to 4.0, placing the HCl aqueous solution in an ultrasonic instrument for 6 minutes by ultrasonic treatment with 600W power, mechanically stirring the HCl aqueous solution for 90 minutes at a temperature of 25 ℃, rotationally evaporating 120mL of water at a vacuum degree of 0.1 atmospheric pressure and 60 ℃, and then drying the solution in vacuum at a vacuum degree of 0.1 atmospheric pressure and 50 ℃ to obtain 9.6 g of nisin complex with a water content of 9.1%.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 180mL of deionized water, the amount of nisin in the nisin control was changed to 1.8 g, and the amount of glyceryl monostearate in the monoglyceride control was changed to 0.2 g, in the same manner as in the other operations.

Staphylococcus aureus bactericidal rate: the bactericidal rate of the compound staphylococcus aureus obtained by the test is 88.7%, the bactericidal rate of the staphylococcus aureus of the glyceryl monostearate is 1.6%, the bactericidal rate of the Nisin staphylococcus aureus is 56.7%, and the bactericidal rate of the compound staphylococcus aureus obtained by the calculation is improved by 53.6%.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 49.9%, the escherichia coli sterilization rate of glyceryl monostearate is 0.5%, the Nisin escherichia coli sterilization rate is 37.2%, and the compound escherichia coli sterilization rate is improved by 32.8% through calculation.

Example 3:

1. nisin complexes

Weighing 7.0 g Nisin (purity 90%) produced by Wuhan Xianbao Biotechnology Ltd, adding into 150mL deionized water, stirring for dissolving, adding 3.0 g glyceryl monostearate (Weifang Shengbaolong Biotechnology Ltd), and adding 0.05 mol. L^-1Adjusting pH to 6.0 with HCl aqueous solution, placing in an ultrasonic instrument for 4 minutes under 600W power ultrasound, mechanically stirring at 25 deg.C for 70 minutes while maintaining the temperature, rotationally evaporating 120mL of water at 60 deg.C under 0.1 atm, and vacuum drying at 50 deg.C under 0.1 atm to obtain 9.7 g of composition with water content of 8.9%.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 140mL of deionized water, the amount of nisin in the nisin control was changed to 1.4 g, and the amount of glyceryl monostearate in the monoglyceride control was changed to 0.6 g, in the same manner as in the other operations.

Staphylococcus aureus bactericidal rate: the sterilization rate of the compound staphylococcus aureus obtained by the test is 87.2%, the sterilization rate of the staphylococcus aureus of glyceryl monostearate is 2.1%, the sterilization rate of the Nisin is 49.3%, and the sterilization rate of the compound staphylococcus aureus obtained by the calculation is improved by 72.7%.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 45.0%, the escherichia coli sterilization rate of glyceryl monostearate is 1.3%, the escherichia coli sterilization rate of Nisin is 30.9%, and the compound escherichia coli sterilization rate is improved by 41.6% through calculation.

Example 4:

1. nisin complexes

Weighing 5.0 g Tianjin KangyiNisin (purity 90%) produced by biological Limited company, adding into 150mL deionized water, stirring and dissolving, adding 5.0 g glyceryl monostearate (Weifang Shengbaolong biological technology Limited company), and adding 0.05 mol. L^-1Adjusting the pH value of the aqueous solution of NaOH to 7.0, placing the aqueous solution of NaOH into an ultrasonic instrument for 5 minutes by ultrasonic treatment with 600W power, mechanically stirring the aqueous solution at the temperature of 25 ℃ for 80 minutes while keeping the temperature, rotationally evaporating 120mL of water at the temperature of 60 ℃ under the vacuum degree of 0.1 atmosphere, and then drying the aqueous solution at the temperature of 50 ℃ under the vacuum degree of 0.1 atmosphere to obtain 9.7 g of nisin compound with the water content of 9.0 percent.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 100mL of deionized water, the amount of nisin in the nisin control was changed to 1.0 g, and the amount of glyceryl monostearate in the monoglyceride control was changed to 1.0 g, in the same manner as in the other operations.

Staphylococcus aureus bactericidal rate: the sterilization rate of the compound staphylococcus aureus obtained by the test is 65.5%, the sterilization rate of the glyceryl monostearate staphylococcus aureus is 2.6%, the sterilization rate of the Nisin staphylococcus aureus is 41.5%, and the sterilization rate of the compound staphylococcus aureus obtained by the calculation is improved by 51.6%.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 36.2%, the glyceryl monostearate escherichia coli sterilization rate is 1.7%, the Nisin escherichia coli sterilization rate is 26.1%, and the compound escherichia coli sterilization rate is improved by 32.3% through calculation.

Example 5:

1. nisin complexes

Weighing 3.0 g Nisin (purity 90%) produced by Wuhan Xianbao Biotechnology Ltd, adding into 150mL deionized water, stirring for dissolving, adding 7.0 g glyceryl monostearate (Weifang Shengbaolong Biotechnology Ltd), and adding 0.05 mol. L^-1Adjusting the pH value of the aqueous solution of NaOH to 8.0, placing the aqueous solution of NaOH into an ultrasonic instrument for ultrasonic treatment with 600W power for 4 minutes, mechanically stirring the aqueous solution at the temperature of 25 ℃ for 90 minutes while keeping the temperature, rotationally evaporating 120mL of water at the temperature of 60 ℃ under the vacuum degree of 0.1 atmosphere, and then drying the aqueous solution at the temperature of 50 ℃ under the vacuum degree of 0.1 atmosphere to obtain 9.6 g of nisin compound with the water content of 8.8 percent.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 60mL of deionized water, the amount of nisin in the nisin control was changed to 0.6 g, and the amount of glyceryl monostearate in the monoglyceride control was changed to 1.4 g, all other operations being the same.

Staphylococcus aureus bactericidal rate: the bactericidal rate of the compound staphylococcus aureus obtained by the test is 58.4%, the bactericidal rate of the glyceryl monostearate staphylococcus aureus is 3.2%, the bactericidal rate of the Nisin staphylococcus aureus is 34.8%, and the bactericidal rate of the compound staphylococcus aureus obtained by the calculation is improved by 58.7%.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 33.1%, the glyceryl monostearate escherichia coli sterilization rate is 2.1%, the Nisin escherichia coli sterilization rate is 22.7%, and the compound escherichia coli sterilization rate is improved by 36.2% through calculation.

Example 6:

1. nisin complexes

Weighing 7.0 g Nisin (purity 90%) produced by Tianjin Kangsheng Probiotics, Inc., adding 150mL deionized water, stirring to dissolve, adding 3.0 g monopalmitin (produced by Sichuan Weickqi Biotech, Inc.), and adding 0.05 mol.L^-1Adjusting pH to 4.0 with HCl aqueous solution, placing the solution in an ultrasonic instrument for 5 minutes by ultrasonic treatment with 600W power, mechanically stirring the solution at 25 ℃ for 80 minutes while keeping the temperature, rotationally evaporating 120mL of water at 60 ℃ under 0.1 atmospheric pressure in a vacuum degree, and then drying the solution at 50 ℃ under 0.1 atmospheric pressure in a vacuum degree to obtain 9.7 g of nisin complex with the water content of 8.9%.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 140mL of deionized water, the dosage of nisin in the nisin control was changed to 1.4 g, and the monoglyceride control was changed to 0.6 g of monopalmitin, and the other operations were the same.

Staphylococcus aureus bactericidal rate: the sterilization rate of the compound staphylococcus aureus obtained by the test is 85.8%, the sterilization rate of the monopalmitin staphylococcus aureus is 2.2%, the sterilization rate of the Nisin staphylococcus aureus is 49.7%, and the sterilization rate of the compound staphylococcus aureus is improved by 68.3% by calculation.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 44.8%, the monopalmitin escherichia coli sterilization rate is 1.2%, the Nisin escherichia coli sterilization rate is 31.2%, and the compound escherichia coli sterilization rate is improved by 39.7% through calculation.

Example 7:

1. nisin complexes

Weighing 7.0 g Nisin (purity 90%) produced by Wuhan Xianbao Biotechnology Co., Ltd., adding into 150mL deionized water, stirring for dissolution, adding 3.0 g glycerol monooleate (produced by Wuhan Shuer Biotechnology Co., Ltd.), and dissolving with 0.05 mol. L^-1Adjusting pH to 5.0 with HCl aqueous solution, placing the solution in an ultrasonic instrument for 5 minutes by ultrasonic treatment with 600W power, keeping the temperature and mechanically stirring the solution for 70 minutes at 25 ℃, rotationally evaporating 120mL of water at 60 ℃ under 0.1 atmospheric pressure in a vacuum degree, and then drying the solution in vacuum at 50 ℃ under 0.1 atmospheric pressure to obtain 9.7 g of nisin compound with the water content of 9.0%.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 140mL of deionized water, the dosage of nisin in the nisin control was changed to 1.4 g, and the monoglyceride control was changed to 0.6 g of glyceryl monooleate, and the other operations were the same.

Staphylococcus aureus bactericidal rate: the sterilization rate of the compound staphylococcus aureus obtained by the test is 85.3%, the sterilization rate of the glyceryl monooleate staphylococcus aureus is 2.3%, the sterilization rate of the Nisin staphylococcus aureus is 49.6%, and the sterilization rate of the compound staphylococcus aureus obtained by the calculation is improved by 67.3%.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 44.4%, the glyceryl monooleate escherichia coli sterilization rate is 1.4%, the Nisin escherichia coli sterilization rate is 31.0%, and the compound escherichia coli sterilization rate is improved by 38.6% through calculation.

Example 8:

1. nisin complexes

Weighing 7.0 g of Wuhan fresh biological techniqueNisin (purity 90%) produced by Kouzu Co., Ltd, was dissolved in 150mL of deionized water under stirring, and 3.0 g of glycerol monolaurate (produced by Shandong daily-use auxiliary agent Co., Ltd., Jiaxing) was added thereto in an amount of 0.05 mol. L^-1Adjusting the pH value of the HCl aqueous solution to 4.0, placing the HCl aqueous solution in an ultrasonic instrument for 5 minutes by ultrasonic treatment with 600W power, keeping the temperature and mechanically stirring the HCl aqueous solution for 70 minutes at 25 ℃, rotationally evaporating 120mL of water at 60 ℃ under the vacuum degree of 0.1 atmosphere, and then drying the solution in vacuum at 50 ℃ under the vacuum degree of 0.1 atmosphere to obtain 9.7 g of nisin compound with the water content of 8.9 percent.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 140mL of deionized water, the amount of nisin in the nisin control was changed to 1.4 g, and the monoglyceride control was changed to 0.6 g of glycerol monolaurate, and the other operations were the same.

Staphylococcus aureus bactericidal rate: the sterilization rate of the compound staphylococcus aureus is 63.8%, the sterilization rate of the glycerol monolaurate staphylococcus aureus is 4.7%, the sterilization rate of the Nisin staphylococcus aureus is 49.4%, and the sterilization rate of the compound staphylococcus aureus is improved by 19.6% by calculation.

The sterilization rate of escherichia coli is as follows: the compound escherichia coli sterilization rate is 35.2%, the glycerol monolaurate escherichia coli sterilization rate is 0.6%, the Nisin escherichia coli sterilization rate is 31.1%, and the compound escherichia coli sterilization rate is increased by 11.4% through calculation.

Example 9:

1. nisin complexes

Weighing 7.0 g Nisin (purity 90%) produced by Tianjin Kan probiotic Co., Ltd, adding into 150mL deionized water, stirring for dissolving, adding 3.0 g monoglyceride (produced by Shanghai Mirui chemical technology Co., Ltd), and dissolving with 0.05 mol. L^-1Adjusting the pH value of the HCl aqueous solution to 4.0, placing the HCl aqueous solution in an ultrasonic instrument for 5 minutes by ultrasonic treatment with 600W power, mechanically stirring the HCl aqueous solution for 80 minutes at the temperature of 25 ℃, rotationally evaporating 120mL of water at the temperature of 60 ℃ under the vacuum degree of 0.1 atmosphere, and then drying the solution in vacuum at the temperature of 50 ℃ under the vacuum degree of 0.1 atmosphere to obtain 9.7 g of nisin compound with the water content of 8.8%.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 140mL of deionized water, the dosage of nisin in the nisin control was changed to 1.4 g, the monoglyceride control was changed to 0.6 g of monoglyceride, and the other operations were the same.

Staphylococcus aureus bactericidal rate: the bactericidal rate of the compound staphylococcus aureus obtained by the test is 56.5%, the bactericidal rate of the monoglyceride staphylococcus aureus is 2.2%, the bactericidal rate of the Nisin staphylococcus aureus is 49.5%, and the bactericidal rate of the compound staphylococcus aureus obtained by the calculation is improved by 9.7%.

The sterilization rate of the compound escherichia coli is as follows: the compound escherichia coli sterilization rate is 33.7%, the monoglyceride sterilization rate of escherichia coli is 0.8%, the Nisin sterilization rate of escherichia coli is 31.2%, and the compound escherichia coli sterilization rate is improved by 5.6% through calculation.

Comparative example:

1. nisin complexes

Weighing 7.0 g Nisin (purity 90%) produced by Tianjin Kangsheng Probiotics, Inc., adding into 150mL deionized water, stirring for dissolving, adding 3.0 g glycerol monononanoate (produced by Shanghai Kogyo chemical technology, Inc.), and dissolving with 0.05 mol.L^{- 1}Adjusting pH to 4.0 with HCl aqueous solution, placing the solution in an ultrasonic instrument for 5 minutes by ultrasonic treatment with 600W power, mechanically stirring the solution at 25 ℃ for 80 minutes while keeping the temperature, rotationally evaporating 120mL of water at 60 ℃ under 0.1 atmosphere of vacuum degree and then drying the solution at 50 ℃ under 0.1 atmosphere of vacuum degree in vacuum degree to obtain 9.8 g of nisin compound with the water content of 9.0 percent.

2. Bacteriostasis test

In the same manner as in example 1, 2.0 g of nisin complex in the complex sterilization test was dissolved in 140mL of deionized water, the dosage of nisin in the nisin control was changed to 1.4 g, and the monoglyceride control was changed to 0.6 g of glycerol monopelargonate, and the other operations were the same.

Staphylococcus aureus bactericidal rate: the bactericidal rate of the compound staphylococcus aureus obtained by the test is 51.8%, the bactericidal rate of the glycerol monopelargonate staphylococcus aureus is 2.7%, the bactericidal rate of the Nisin staphylococcus aureus is 49.3%, and the bactericidal rate of the compound staphylococcus aureus obtained by the calculation is not improved.

The sterilization rate of the compound escherichia coli is as follows: the compound escherichia coli sterilization rate is 32.3%, the glycerol monopelargonate escherichia coli sterilization rate is 1.1%, the Nisin escherichia coli sterilization rate is 31.3%, and the compound escherichia coli sterilization rate obtained through calculation is not improved.