Preparation method of nanocellulose antibacterial sustained-release film

[0020] Example 1

[0021] The preparation method of a nano-cellulose antibacterial sustained-release film is as follows:

[0022] 1) Using bleached bagasse fibers as raw materials, a 5% mass concentration of nanocellulose colloid is prepared by mechanical grinding, and the obtained nanocellulose has a diameter of 2-20nm and a length of 0.1-100μm;

[0023] 2) Weigh 100 parts (by weight, the same below) nano cellulose colloid, 0.08 parts 2,2,6,6-tetramethylpiperidine-1-oxide powder and 0.52 parts NaBr powder, and mix them at room temperature Evenly dilute with distilled water to a solid content of 1%, add 0.4 parts of NaClO solution with an effective chlorine concentration of 112g/l, and then use a 0.5mol/L hydrochloric acid solution to adjust the pH of the system to 10 and keep the reaction temperature at 25°C. During the reaction, the pH value of the system keeps decreasing. The pH value of the system is maintained at 10 by dripping sodium hydroxide solution with a concentration of 0.5mol/L. When the pH value of the system remains unchanged at 10, 10 parts of the system are added to the system. Water ethanol to complete the reaction; followed by high-speed centrifugal washing until the supernatant is dripped with HNO 3 And AgNO 3 Until the solution does not appear flocculent precipitation, the oxidized nano cellulose slow-release control agent is prepared;

[0024] 3) Weigh 100 parts of nano cellulose colloid and 10 parts of the oxidized nano cellulose sustained-release control agent prepared in step 2), mix them uniformly at room temperature and dilute with distilled water to a mass concentration of 1%, ultrasonic treatment for 10 minutes, and magnetically stir for 1 hour , To prepare a mixed nano-cellulose suspension;

[0025] 4) Dissolve nisin powder in a hydrochloric acid solution with a pH of 2, and stir magnetically for 4 hours at room temperature to prepare a nisin solution with a mass concentration of 1%, and add this solution to the prepared solution in step 3) In the mixed nano cellulose suspension, magnetic stirring is applied for 4 hours to prepare a film-forming liquid, and the mass concentration of nisin in the film-forming liquid is 0.2%;

[0026] 5) Cast the film-forming liquid prepared in step 4) into a mold, and place it in an oven at a temperature of 50° C. to dry for 24 hours to obtain a nano-cellulose antibacterial sustained-release film.

[0027] The antibacterial performance of the obtained nanocellulose antibacterial sustained-release film was analyzed: the same amount of Listeria liquid was applied to both sides of the sheet-shaped instant ham slice, and the nanocellulose antibacterial sustained-release film was attached to both sides of the instant ham surface. Then put the instant ham slices into a PET plastic tape for vacuum packaging, and refrigerate at 4°C. The number of bacterial colonies on the surface of the instant ham after 60 days of refrigeration was measured by the coating method to determine the slowness of the nanocellulose antibacterial sustained-release film. Interpretation effect. The bacteria on the surface of the ham packaged in the antibacterial film without adding the oxidized nanocellulose slow-release agent began to grow on the 7th day, while the bacteria on the surface of the ham packaged with the antibacterial slow-release film of the oxidized nanocellulose slow-release agent did not appear on the 14th day The appearance of growth indicates that the addition of oxidized nanocellulose can effectively control the release rate of nisin, and can effectively ensure that the nisin concentration on the surface of the ham is always higher than the minimum inhibitory concentration of bacteria during the 14-day storage period. Inhibit bacterial proliferation.

[0028] Example 2

[0029] The preparation method of a nano-cellulose antibacterial sustained-release film is as follows:

[0030] 1) Using bleached softwood fibers as raw materials, a 5% mass concentration of nanocellulose colloid is prepared by mechanical grinding, and the obtained nanocellulose has a diameter of 2-20nm and a length of 0.1-100μm;

[0031] 2) Weigh 100 parts (by weight, the same below) nano cellulose colloid, 0.08 parts 2,2,6,6-tetramethylpiperidine-1-oxide powder and 0.52 parts NaBr powder, and mix them at room temperature Evenly dilute with distilled water to a solid content of 1%, add 2 parts of NaClO solution with an available chlorine concentration of 112g/l, and then use a 0.5mol/L hydrochloric acid solution to adjust the pH of the system to 10 and keep the reaction temperature at 25°C. During the reaction, the pH value of the system keeps decreasing. The pH value of the system is maintained at 10 by dripping sodium hydroxide solution with a concentration of 0.5mol/L. When the pH value of the system remains unchanged at 10, 10 parts of the system are added to the system. Water ethanol to complete the reaction; followed by high-speed centrifugal washing until the supernatant is dripped with HNO 3 And AgNO 3 Until the solution does not appear flocculent precipitation, the oxidized nano cellulose slow-release control agent is prepared;

[0032] 3) Weigh 100 parts of nano cellulose colloid and 50 parts of the oxidized nano cellulose sustained-release control agent prepared in step 2), mix them uniformly at room temperature and dilute with distilled water to a mass concentration of 1%, ultrasonic treatment for 10 minutes, and magnetically stir for 1 hour, Prepare a mixed nano cellulose suspension;

[0033] 4) Dissolve nisin powder in a hydrochloric acid solution with a pH of 2, and stir magnetically for 4 hours at room temperature to prepare a nisin solution with a mass concentration of 1%, and add this solution to the prepared solution in step 3) In the mixed nano-cellulose suspension, magnetic stirring is applied for 4 hours to prepare a film-forming liquid, and the mass concentration of nisin in the film-forming liquid is 0.3%;

[0034] 5) Cast the film-forming liquid prepared in step 4) into a mold, and place it in an oven at a temperature of 50° C. to dry for 24 hours to obtain a nano-cellulose antibacterial sustained-release film.

[0035] Perform performance analysis of the obtained nano-cellulose antibacterial sustained-release film: apply the same amount of Listeria liquid on both sides of the sheet-shaped instant ham slice, and stick the nano-cellulose antibacterial sustained-release film on both sides of the instant ham surface, and then Put the instant ham slices into a PET plastic tape for vacuum packaging, and refrigerate at 4°C. The number of bacterial colonies on the surface of instant ham within 60 days of refrigeration was measured by the coating method to determine the slowness of the nanocellulose antibacterial sustained-release film. Interpretation effect. The bacteria on the surface of the ham packaged with the antibacterial film without adding the oxidized nanocellulose slow-release agent began to grow on the 14th day, while the bacteria on the ham surface packaged with the antibacterial slow-release film of the oxidized nanocellulose slow-release agent did not appear on the 20th day The appearance of growth indicates that the addition of oxidized nanocellulose can effectively control the release rate of nisin, and can effectively ensure that the nisin concentration on the surface of the ham is always higher than the minimum inhibitory concentration of bacteria during the storage period of 20 days. Inhibit bacterial proliferation.

[0036] Example 3

[0037] The preparation method of a nano-cellulose antibacterial sustained-release film is as follows:

[0038] 1) Using bleached hardwood fibers as raw materials, a 5% mass concentration of nanocellulose colloid is prepared by mechanical grinding, and the obtained nanocellulose has a diameter of 2-20nm and a length of 0.1-100μm;

[0039] 2) Weigh 100 parts (parts by weight, the same below) of nano cellulose colloid, 0.08 parts of 2,2,6,6-tetramethylpiperidine-1-oxide (TEMPO) powder and 0.52 parts of NaBr powder. Mix well at room temperature and dilute with distilled water to a solid content of 1%, add 4 parts of NaClO solution with an available chlorine concentration of 112g/l, and then use a 0.5mol/L hydrochloric acid solution to adjust the pH of the system to 10, keeping the reaction temperature at At 25°C, the pH value of the system keeps decreasing during the reaction. The pH value of the system is maintained at 10 by dripping sodium hydroxide solution with a concentration of 0.5 mol/L until the pH value of the system remains unchanged at 10, add to the system 10 parts of absolute ethanol to complete the reaction; then centrifuge and wash at high speed until the supernatant is dripped with HNO 3 And AgNO 3 Until the solution does not appear flocculent precipitation, the oxidized nano cellulose slow-release control agent is prepared;

[0040] 3) Weigh 100 parts of nano cellulose colloid and 100 parts of oxidized nano cellulose sustained-release control agent prepared in step 2), mix them uniformly at room temperature and dilute with distilled water to a mass concentration of 1%, ultrasonic treatment for 10 minutes, and magnetically stir for 1 hour , To prepare a mixed nano-cellulose suspension;

[0041] 4) Dissolve nisin powder in a hydrochloric acid solution with a pH of 2, and stir magnetically for 4 hours at room temperature to prepare a nisin solution with a mass concentration of 1%, and add this solution to the prepared solution in step 3) In the mixed nano-cellulose suspension, magnetic stirring is applied for 4 hours to prepare a film-forming liquid, and the mass concentration of nisin in the film-forming liquid is 0.5%;

[0042] 5) Cast the film-forming liquid prepared in step 4) into a mold, and place it in an oven at a temperature of 50° C. to dry for 24 hours to obtain a nano-cellulose antibacterial sustained-release film.

[0043] Perform performance analysis of the obtained nano-cellulose antibacterial sustained-release film: apply the same amount of Listeria liquid on both sides of the sheet-shaped instant ham slice, and stick the nano-cellulose antibacterial sustained-release film on both sides of the instant ham surface, and then Put the instant ham slices in a PET plastic tape for vacuum packaging, refrigerate at 4°C, and measure the number of bacterial colonies on the surface of instant ham within 60 days of refrigeration by the coating method to determine the sustained release of the nanocellulose antibacterial sustained-release film effect. The bacteria on the surface of the ham packaged with the antibacterial film without the oxidized nanocellulose slow-release agent began to grow on the 21st day, while the bacteria on the ham surface packaged with the antibacterial slow-release film of the oxidized nanocellulose slow-release agent did not appear on the 40th day The appearance of growth indicates that the addition of oxidized nanocellulose can effectively control the release rate of nisin, and can effectively ensure that the nisin concentration on the surface of the ham is always higher than the minimum inhibitory concentration of bacteria during the 40-day storage period, thus effective Inhibit bacterial proliferation.