A method for improving the whiteness of nisin finished product

Abstract

The invention discloses a method for improving the whiteness of nisin finished product, comprising the steps: 1) nisin wet powder is stirred with water until completely dissolved, and then pH is adjusted to 3.0-9.0; 2) solid NaCl is added to the solution obtained in step 1), stirred until solid NaCl is completely dissolved, and then filtered to obtain a filter cake; 3) the filter cake obtained in step 2) is redissolved with water, pH is adjusted to 1.5-3.0, an appropriate amount of solid NaCl is added, sheared evenly, and then spray-dried to obtain nisin dry powder finished product. Compared with traditional decolorization process, the inventive method can not only significantly improve the whiteness of nisin finished product, but also has a higher total yield, simple to operate, less wastewater, low process cost, high processing capacity, easy to large-scale workshop production, and is conducive to expanding the application of nisin in the fields of food and medicine.

Description

Technical Field

[0001] The invention relates to the technical field of nisin whiteness, and in particular to a method for improving the whiteness of a nisin finished product. Background Art

[0002] Nisin is a natural non-toxic polypeptide antibacterial substance, which is composed of 34 amino acids, has a positive charge and is mainly produced by Lactococcus lactis. Nisin has good antibacterial ability and has an inhibitory effect on most Gram-positive bacteria. At the same time, nisin is highly safe to use and can be absorbed and utilized by the human body. Therefore, as the only bacteriocin allowed to be used as a food additive, nisin has been widely used as a biological preservative for foods such as dairy products, meat, seafood and beverages. In addition, since nisin is less likely to cause bacteria to develop drug resistance, it has the potential to be used as an antibiotic substitute in certain infectious diseases (such as mastitis, respiratory tract infections, gastrointestinal infections and skin infections, etc.), and also has the potential to prevent and treat oral diseases such as caries and periodontal disease, and also has certain application value in the field of medicine.

[0003] At present, fermentation is still the main method of nisin production, but the fermentation product has a complex composition, and has higher requirements for extraction and purification, and the nisin finished product obtained by traditional production technology is often darker in color. Along with the continuous development of social productivity, the requirement of consumer to product quality is constantly improved, and the pigment residue in the nisin finished product can affect product color and quality, and affects its application in fields such as food. But less related research about removing nisin pigment at present, a kind of chromatographic system is designed in the patent documentation of CN112957771A, although nisin pigment etc. can be adsorbed, and preferably retain nisin activity, but it uses silica gel column complicated operation, and can increase organic solvent wastewater and process cost is high, equipment processing capacity is small in the process, and still has greater difficulty in actual applications.

[0004] Therefore, how to remove the pigment in nisin and improve the whiteness of the finished nisin product is still a major problem that needs to be solved in its production process. Summary of the invention

[0005] The purpose of the present invention is to provide a method for improving the whiteness of a finished nisin product, so as to solve the problem that the existing finished nisin product has a dark color, which affects the scope of use of the product and interferes with the quality of food, etc. In addition, the method of the present invention can significantly improve the whiteness of the finished nisin product and also has a higher total yield.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for improving the whiteness of a nisin finished product comprises the following steps:

[0008] 1) Add water to the nisin wet powder and stir until it is completely dissolved, then adjust the pH to 3.0-9.0;

[0009] 2) Add solid NaCl to the solution obtained in step 1), stir until the solid NaCl is completely dissolved, and then filter to obtain a filter cake;

[0010] 3) The filter cake obtained in step 2) is redissolved in water, the pH is adjusted to 1.5-3.0, an appropriate amount of solid NaCl is added, sheared evenly, and then spray-dried to obtain a finished lactic acid streptococcus dry powder.

[0011] Furthermore, in step 1), water is added to the nisin wet powder and stirred until it is completely dissolved, and then the pH is adjusted to 5.0-7.0.

[0012] Furthermore, in step 1), the potency of nisin wet powder is 7000-9000 IU / mg, and the nisin wet powder is added with water and stirred until completely dissolved to prepare a solution of 100,000 to 500,000 IU / mL water, and then the pH is adjusted.

[0013] Furthermore, in step 1), 1-2 mol / L NaOH is used to adjust the pH; in step 3), concentrated hydrochloric acid is used to adjust the pH.

[0014] Furthermore, in step 2), the mass of solid NaCl added is 10%-20% of the volume of the solution obtained in step 1), the mass of solid NaCl added is measured in g, and the volume of the solution obtained in step 1) is measured in mL.

[0015] Furthermore, in step 2), a plate and frame filter is used for filtration.

[0016] Further, in step 3), the mass m4 of water added for re-dissolution is calculated according to the following formula:

[0017] (m2+m3×filter biscuit material ratio) / m4×100%=30wt%-35wt%

[0018] Wherein, m2 is the mass of solid NaCl added in step 2), and m3 is the mass of filter cake.

[0019] Further, in step 3), the mass m5 of solid NaCl added is calculated according to the following calculation formula:

[0020] m5 = (m3 × filter cake potency) / target potency of nisin dry powder finished product - m3 × filter cake material ratio, where m3 is the filter cake mass.

[0021] Furthermore, in step 3), a shear pump is used for uniform shearing.

[0022] Furthermore, in step 3), spray drying is performed using a spray drying device, the inlet air temperature of the spray drying device is 160-180°C, and the outlet air temperature is 80-90°C.

[0023] Beneficial effects of the present invention:

[0024] Nisin is a kind of active polypeptide. In the actual production process, it is difficult to separate pigment and product by the method of physical separation. Resin decolorization operation is complicated, wastewater volume is large, process cost is high, and treatment capacity is small, and some other chemical decolorization methods cannot reach balance in yield and decolorization effect. The present invention has found that under different pH, pigment has larger solubility difference in a certain salt concentration, thereby realizes that the pigment in nisin is deviated from, and this condition can not cause greater loss to nisin, it can make nisin finished product whiteness improve about 21%, and total recovery reaches about 93% (comparison of embodiment 3 test group and control group). Compared with traditional decolorization process, the inventive method can not only significantly improve nisin finished product whiteness, and has higher total recovery, simple to operate simultaneously, less wastewater volume, low process cost, high treatment capacity, easy to workshop large-scale production, conducive to expanding the application of nisin in fields such as food and medicine. DETAILED DESCRIPTION

[0025] The present invention is further explained below in conjunction with the examples. The following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] A method for improving the whiteness of a nisin finished product comprises the following steps:

[0027] 1) Add water to the nisin wet powder and stir until it is completely dissolved, then use 1-2 mol / L NaOH to adjust the pH to 3.0-9.0, preferably, adjust the pH to 5.0-7.0; optionally, the nisin wet powder has a potency of 7000-9000 IU / mg, add water to the nisin wet powder and stir until it is completely dissolved to prepare a solution of 100000 to 500000 IU / mL water, and then adjust the pH;

[0028] 2) adding solid NaCl to the solution obtained in step 1), stirring until the solid NaCl is completely dissolved, and then filtering with a plate-and-frame filter to obtain a filter cake; wherein the mass of the solid NaCl added is 10%-20% of the volume of the solution obtained in step 1), the mass of the solid NaCl added is measured in g, and the volume of the solution obtained in step 1) is measured in mL;

[0029] 3) The filter cake obtained in step 2) is redissolved with water, the pH is adjusted to 1.5-3.0 with concentrated hydrochloric acid, an appropriate amount of solid NaCl is added, and the mixture is sheared evenly with a shear pump, and then spray-dried with a spray drying device, the inlet air temperature of the spray drying device is 160-180°C, and the outlet air temperature is 80-90°C, to obtain a finished product of lactic acid streptococcus dry powder; wherein the mass m4 of water added for redissolution is calculated according to the following formula:

[0030] (m2+m3×filter biscuit material ratio) / m4×100%=30wt%-35wt%

[0031] Wherein, m2 is the mass of solid NaCl added in step 2), and m3 is the mass of filter cake;

[0032] The mass m5 of solid NaCl added is calculated according to the following formula:

[0033] m5 = (m3 × filter cake potency) / target potency of nisin dry powder finished product - m3 × filter cake material ratio, where m3 is the filter cake mass.

[0034] Example 1

[0035] The conventional nisin wet powder produced in the workshop (the potency of nisin wet powder was 7958 IU / mg, and the dry matter ratio of nisin wet powder was 61.2 wt%) was evenly divided into two groups, one group as the experimental group and the other group as the control group.

[0036] The experimental group was operated as follows: Nisin wet powder (the mass of nisin wet powder was recorded as m1) was added with water and stirred until completely dissolved, and a solution of 300000 IU / mL water was prepared, and then 1 mol / L NaOH was added to adjust the pH of the solution to 3.0. 20% (m / v, solid NaCl mass (g) / volume of solution after pH adjustment (mL)) of solid NaCl (the mass of solid NaCl added was recorded as m2) was added to the solution after pH adjustment, and stirred until the solid NaCl was completely dissolved, and then filtered using a plate and frame filter to collect the filter cake (the mass of the filter cake was recorded as m3, the filter cake titer was 8692 IU / mg, and the filter cake material accounted for 60.5wt%). The obtained filter cake was redissolved in water (the mass of water added for redissolution was recorded as m4, and m4 was calculated according to the following calculation formula: (m2+m3×filter cake material ratio) / m4×100%=30wt%-35wt%, and the filter cake material ratio was 60.5wt%), concentrated hydrochloric acid was used to adjust the pH of the solution to 2.02, and an appropriate amount of solid NaCl was added (the mass of the added solid NaCl was recorded as m5, and m5 was calculated according to the following calculation formula: m5=(m3×filter cake potency) / target potency of nisin dry powder finished product-m3×filter cake material ratio, the filter cake potency was 8692IU / mg, the target potency of nisin dry powder finished product was 1200IU / mg, and the filter cake material ratio was 60.5wt%), and a shear pump was used to shear evenly, and then spray-dried, the inlet air temperature of the spray drying equipment was 160°C, and the outlet air temperature was 85°C, to obtain a nisin dry powder finished product with a potency of 1192IU / mg. Measured by whiteness measuring instrument, the whiteness of nisin dry powder finished product is 55.2%, and the total recovery (total recovery=effective unit of final product / effective unit of initial material×100%, effective unit of final product=titer of nisin dry powder finished product (1192IU / mg)×quality of nisin dry powder finished product, effective unit of initial material=titer of nisin wet powder (7958IU / mg)×quality of nisin wet powder) is 95.69%.

[0037] The control group was operated as follows: Nisin wet powder (the mass of nisin wet powder is also m1) was added with water and stirred until completely dissolved to prepare a solution of 300000 IU / mL water, and solid NaCl was added (the mass of solid NaCl added was calculated as follows: m1×nisin wet powder potency / nisin dry powder finished product target potency-m1×nisin wet powder dry matter ratio, nisin wet powder potency is 7958 IU / mg, nisin The target potency of the finished nisin dry powder is 1200 IU / mg, and the dry matter proportion of nisin wet powder is 61.2 wt %), the shearing is uniformly sheared using a shear pump, and spray drying (the spray drying operation is the same as the test group) is the same potency (the same potency means that the target potency of the nisin dry powder finished products in the control group and the test group is the same, both of which are 1200 IU / mg) as a control, and the whiteness of the nisin dry powder finished product in the control group is 47.0% (the whiteness determination method is the same as the test group).

[0038] Example 2

[0039] The conventional nisin wet powder produced in the workshop (the potency of nisin wet powder was 8451 IU / mg, and the dry matter proportion of nisin wet powder was 57.8 wt%) was evenly divided into two groups, one group as the experimental group and the other group as the control group.

[0040] The experimental group was operated as follows: Nisin wet powder (the mass of nisin wet powder was recorded as m1) was added with water and stirred until completely dissolved, and a solution of 300000 IU / mL water was prepared, and then 1 mol / L NaOH was added to adjust the pH of the solution to 5.0. 20% (m / v, solid NaCl mass (g) / volume of solution after pH adjustment (mL)) of solid NaCl (the mass of solid NaCl added was recorded as m2) was added to the solution after pH adjustment, and stirred until the solid NaCl was completely dissolved, and then filtered using a plate and frame filter to collect the filter cake (the mass of the filter cake was recorded as m3, the filter cake titer was 8869 IU / mg, and the filter cake material accounted for 59.1wt%). The obtained filter cake was redissolved in water (the mass of water added for redissolution was recorded as m4, and m4 was calculated according to the following calculation formula: (m2+m3×filter cake material ratio) / m4×100%=30wt%-35wt%, and the filter cake material ratio was 59.1wt%), concentrated hydrochloric acid was used to adjust the pH of the solution to 1.97, and an appropriate amount of solid NaCl was added (the mass of the added solid NaCl was recorded as m5, and m5 was calculated according to the following calculation formula: m5=(m3×filter cake potency) / target potency of nisin dry powder finished product-m3×filter cake material ratio, the filter cake potency was 8869IU / mg, the target potency of nisin dry powder finished product was 1200IU / mg, and the filter cake material ratio was 59.1wt%), and a shear pump was used to shear evenly, and then spray-dried, the inlet air temperature of the spray drying equipment was 160°C, and the outlet air temperature was 85°C, to obtain a nisin dry powder finished product with a potency of 1205IU / mg. Measured by whiteness measuring instrument, the whiteness of nisin dry powder finished product is 61.5%, and the total recovery (total recovery=effective unit of final product / effective unit of initial material×100%, effective unit of final product=titer of nisin dry powder finished product (1205IU / mg)×quality of nisin dry powder finished product, effective unit of initial material=titer of nisin wet powder (8451IU / mg)×quality of nisin wet powder) is 93.45%.

[0041] The control group was operated as follows: Nisin wet powder (the mass of nisin wet powder is also m1) was added with water and stirred until completely dissolved to prepare a solution of 300000 IU / mL water, and solid NaCl was added (the mass of solid NaCl added was calculated as follows: m1×nisin wet powder potency / nisin dry powder finished product target potency-m1×nisin wet powder dry matter ratio, nisin wet powder potency was 8451 IU / mg, nisin The target potency of the finished nisin dry powder is 1200 IU / mg, and the dry matter proportion of nisin wet powder is 57.8wt%), the shearing is uniformly sheared using a shear pump, and spray drying (the spray drying operation is the same as the test group) is the same potency (the same potency means that the target potency of the nisin dry powder finished products in the control group and the test group is the same, both of which are 1200 IU / mg) as a control, and the whiteness of the nisin dry powder finished product in the control group is 46.1% (the whiteness determination method is the same as the test group).

[0042] Example 3

[0043] The conventional nisin wet powder produced in the workshop (the potency of nisin wet powder was 7402 IU / mg, and the dry matter of nisin wet powder accounted for 60.1 wt%) was evenly divided into two groups, one as the experimental group and the other as the control group.

[0044] The experimental group was operated as follows: Nisin wet powder (the mass of nisin wet powder was recorded as m1) was added with water and stirred until completely dissolved, and a solution of 300000 IU / mL water was prepared, and then 1 mol / L NaOH was added to adjust the pH of the solution to 7.0. 20% (m / v, solid NaCl mass (g) / volume of solution after pH adjustment (mL)) of solid NaCl (the mass of solid NaCl added was recorded as m2) was added to the solution after pH adjustment, and stirred until the solid NaCl was completely dissolved, and then filtered using a plate and frame filter to collect the filter cake (the mass of the filter cake was recorded as m3, the filter cake titer was 8024 IU / mg, and the filter cake material accounted for 59.0wt%). The obtained filter cake was redissolved in water (the mass of water added for redissolution was recorded as m4, and m4 was calculated according to the following calculation formula: (m2+m3×filter cake material ratio) / m4×100%=30wt%-35wt%, and the filter cake material ratio was 59.0wt%), concentrated hydrochloric acid was used to adjust the pH of the solution to 2.03, and an appropriate amount of solid NaCl was added (the mass of the added solid NaCl was recorded as m5, and m5 was calculated according to the following calculation formula: m5=(m3×filter cake potency) / target potency of nisin dry powder finished product-m3×filter cake material ratio, the filter cake potency was 8024IU / mg, the target potency of nisin dry powder finished product was 1200IU / mg, and the filter cake material ratio was 59.0wt%), and a shear pump was used to shear evenly, and then spray-dried, the inlet air temperature of the spray drying equipment was 160°C, and the outlet air temperature was 85°C, to obtain a nisin dry powder finished product with a potency of 1185IU / mg. Measured by whiteness measuring instrument, the whiteness of nisin dry powder finished product is 65.9%, and the total recovery (total recovery=effective unit of final product / effective unit of initial material×100%, effective unit of final product=titer of nisin dry powder finished product (1185IU / mg)×quality of nisin dry powder finished product, effective unit of initial material=titer of nisin wet powder (7402IU / mg)×quality of nisin wet powder) is 92.85%.

[0045] The control group was operated as follows: Nisin wet powder (the mass of nisin wet powder is also m1) was added with water and stirred until completely dissolved to prepare a solution of 300000 IU / mL water, and solid NaCl was added (the mass of solid NaCl added was calculated as follows: m1×nisin wet powder potency / nisin dry powder finished product target potency-m1×nisin wet powder dry matter ratio, nisin wet powder potency is 7402 IU / mg, nisin The target potency of the finished nisin dry powder is 1200 IU / mg, and the dry matter proportion of nisin wet powder is 60.1 wt%), the shearing is uniformly sheared using a shear pump, and spray drying (the spray drying operation is the same as the test group) is the same potency (the same potency means that the target potency of the nisin dry powder finished products in the control group and the test group is the same, both of which are 1200 IU / mg) as a control, and the whiteness of the nisin dry powder finished product in the control group is 45.3% (the whiteness determination method is the same as the test group).

[0046] Example 4

[0047] The conventional nisin wet powder produced in the workshop (the potency of nisin wet powder was 8273 IU / mg, and the dry matter of nisin wet powder accounted for 59.3 wt%) was evenly divided into two groups, one as the test group and the other as the control group.

[0048] The experimental group was operated as follows: Nisin wet powder (the mass of nisin wet powder was recorded as m1) was added with water and stirred until completely dissolved, and a solution of 300000 IU / mL water was prepared, and then 1 mol / L NaOH was added to adjust the pH of the solution to 9.0. 20% (m / v, solid NaCl mass (g) / volume of solution after pH adjustment (mL)) of solid NaCl (the mass of solid NaCl added was recorded as m2) was added to the solution after pH adjustment, and stirred until the solid NaCl was completely dissolved, and then filtered using a plate and frame filter to collect the filter cake (the mass of the filter cake was recorded as m3, the filter cake titer was 8934 IU / mg, and the filter cake material accounted for 57.1wt%). The obtained filter cake was redissolved in water (the mass of water added for redissolution was recorded as m4, and m4 was calculated according to the following calculation formula: (m2+m3×filter cake material ratio) / m4×100%=30wt%-35wt%, and the filter cake material ratio was 57.1wt%), concentrated hydrochloric acid was used to adjust the pH of the solution to 2.05, and an appropriate amount of solid NaCl was added (the mass of the added solid NaCl was recorded as m5, and m5 was calculated according to the following calculation formula: m5=(m3×filter cake potency) / target potency of nisin dry powder finished product-m3×filter cake material ratio, the filter cake potency was 8934IU / mg, the target potency of nisin dry powder finished product was 1200IU / mg, and the filter cake material ratio was 57.1wt%), and a shear pump was used to shear evenly, and then spray-dried, the inlet air temperature of the spray drying equipment was 160°C, and the outlet air temperature was 85°C, to obtain a nisin dry powder finished product with a potency of 1213IU / mg. Measured by whiteness measuring instrument, the whiteness of nisin dry powder finished product is 69.1%, and the total recovery (total recovery=effective unit of final product / effective unit of initial material×100%, effective unit of final product=titer of nisin dry powder finished product (1213IU / mg)×quality of nisin dry powder finished product, effective unit of initial material=titer of nisin wet powder (8273IU / mg)×quality of nisin wet powder) is 80.21%.

[0049] The control group was operated as follows: Nisin wet powder (the mass of nisin wet powder is also m1) was added with water and stirred until completely dissolved to prepare a solution of 300000 IU / mL water, and solid NaCl was added (the mass of solid NaCl added was calculated as follows: m1×nisin wet powder potency / nisin dry powder finished product target potency-m1×nisin wet powder dry matter ratio, nisin wet powder potency is 8273 IU / mg, nisin The target potency of the finished nisin dry powder is 1200 IU / mg, and the dry matter proportion of nisin wet powder is 59.3 wt %), the shearing is uniformly sheared using a shear pump, and spray drying (the spray drying operation is the same as the test group) is the same potency (the same potency means that the target potency of the nisin dry powder finished products in the control group and the test group is the same, both of which are 1200 IU / mg) as a control, and the whiteness of the nisin dry powder finished product in the control group is 43.8% (the whiteness determination method is the same as the test group).

[0050] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. It should be pointed out that for ordinary technicians in this technical field, various changes and modifications can be made without departing from the spirit and scope of the present invention. These changes and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for improving the whiteness of a finished nisin product, characterized in that: The steps include: 1) Add water to the nisin wet powder and stir until it is completely dissolved, then adjust the pH to 3.0-9.0; 2) Add solid NaCl to the solution obtained in step 1), stir until the solid NaCl is completely dissolved, and then filter to obtain a filter cake; wherein the mass of the solid NaCl added is 10%-20% of the volume of the solution obtained in step 1), the mass of the solid NaCl added is measured in g, and the volume of the solution obtained in step 1) is measured in mL; 3) The filter cake obtained in step 2) is redissolved in water, the pH is adjusted to 1.5-2.05, an appropriate amount of solid NaCl is added, sheared evenly, and then spray-dried to obtain a finished lactic acid streptococcus dry powder.

2. A method for improving the whiteness of a nisin finished product according to claim 1, characterized in that: In step 1), water is added to the nisin wet powder and stirred until it is completely dissolved, and then the pH is adjusted to 5.0-7.

0.

3. A method for improving the whiteness of a nisin finished product according to claim 1 or 2, characterized in that: In step 1), the potency of nisin wet powder is 7000-9000 IU / mg. The nisin wet powder is added with water and stirred until completely dissolved to prepare a solution of 100,000 to 500,000 IU / mL water, and then the pH is adjusted.

4. A method for improving the whiteness of a nisin finished product according to claim 1 or 2, characterized in that: In step 1), 1-2 mol / L NaOH is used to adjust the pH; in step 3), concentrated hydrochloric acid is used to adjust the pH.

5. A method for improving the whiteness of a finished nisin product according to claim 1 or 2, characterized in that: In step 2), a plate and frame filter is used for filtration.

6. A method for improving the whiteness of a nisin finished product according to claim 1 or 2, characterized in that: In step 3), the mass m4 of water added for re-dissolution is calculated according to the following formula: (m2+m3×filter biscuit material ratio) / m4×100%=30wt%-35wt% Wherein, m2 is the mass of solid NaCl added in step 2), and m3 is the mass of filter cake.

7. A method for improving the whiteness of a nisin finished product according to claim 1 or 2, characterized in that: In step 3), the mass m5 of solid NaCl added is calculated according to the following formula: m5 = (m3 × filter cake potency) / target potency of nisin dry powder finished product - m3 × filter cake material ratio, where m3 is the filter cake mass.

8. A method for improving the whiteness of a nisin finished product according to claim 1 or 2, characterized in that: In step 3), a shear pump is used to shear uniformly.

9. A method for improving the whiteness of a finished nisin product according to claim 1 or 2, characterized in that: In step 3), spray drying is performed using a spray drying device, the inlet air temperature of the spray drying device is 160-180°C, and the outlet air temperature is 80-90°C.