Preparation method and application of nano material for prolonging fresh-keeping period of pork

Abstract

The invention provides a preparation method of a nano material for prolonging the fresh-keeping period of pork, which comprises the following steps: (1) preparing a dandelion extract: mixing dandelion powder and ethanol with the volume fraction of 60-80% according to the material-liquid ratio of 1: 30 by adopting an ultrasonic-assisted ethanol extraction method, and extracting for 60 minutes at the temperature of 60 DEG C to obtain the dandelion ethanol extract; (2) decolorizing the dandelion extract: carrying out decolorizing treatment on the dandelion extract by adopting macroporous resin, wherein the adsorption time is 4-5 hours; the sample loading concentration is 30-50 mg / mL; the loading volume is 2-4 BV; the concentration of the eluent is 60-80%; the volume of the eluent is 5-7 BV; and (3) preparation of nanoparticles: dissolving zein and chitosan in ethanol according to a mass ratio of 5: 1, adding 30mg / mL dandelion ethanol extract, uniformly stirring, and carrying out an ultrasonic-assisted anti-solvent precipitation method. The nano material disclosed by the invention has a longer fresh-keeping period and a better fresh-keeping effect, and the nano material is simple in preparation process, low in cost and good in application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of food preservation, and particularly relates to a preparation method and application of a nanomaterial for prolonging the shelf life of pork. Background Art

[0002] As one of the most consumed meats globally, the research on the preservation technology of pork is of great importance. In the existing technology, pork is vulnerable to microbial contamination and oxidation during storage, resulting in a shortened shelf life and deteriorated quality. Traditional preservation methods (such as low-temperature refrigeration and vacuum packaging) can delay spoilage, but still have problems such as high cost, complex operation, and safety disputes over chemical additives.

[0003] In recent years, bio-based nanomaterials have received attention due to their environmental friendliness and biocompatibility. However, existing nanomaterials still have deficiencies in antibacterial activity, antioxidant stability, and compatibility with food matrices. For example, single chitosan nanoparticles have limited antibacterial effects and are easily affected by the pH environment; zein nanoparticles can encapsulate active ingredients, but have weak mechanical properties. Therefore, there is an urgent need to develop an efficient, stable, and safe nano-preservation material. Summary of the Invention

[0004] Aiming at the above deficiencies in the existing technology, the purpose of the present invention is to provide a preparation method of a nanomaterial for prolonging the shelf life of pork. This nanomaterial has good antioxidant and antibacterial properties, can effectively extend the shelf life of pork, and maintain its freshness and quality at the same time.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A preparation method of a nanomaterial for prolonging the shelf life of pork, including the following steps:

[0006] (1) Preparation of dandelion extract: Using ultrasonic-assisted ethanol extraction method, mix dandelion powder with ethanol with a volume fraction of 60 - 80% at a solid-liquid ratio of 1:30, and extract at 60°C for 60 minutes to obtain dandelion ethanol extract;

[0007] (2) Decolorization treatment of dandelion extract: Use macroporous resin to decolorize the above dandelion extract, with an adsorption time of 4 - 5 hours; a loading concentration of 30 - 50 mg / mL; a loading volume of 2 - 4 BV; an eluent concentration of 60 - 80%; an eluent volume of 5 - 7 BV;

[0008] (3) Preparation of nanoparticles: Dissolve zein and chitosan in ethanol at a mass ratio of 5:1, add 30 mg / mL of the dandelion ethanol extract obtained in step (2), stir evenly, and then use ultrasonic-assisted antisolvent precipitation method.

[0009] Further, in step (1), the ultrasonic-assisted ethanol extraction method is specifically as follows: Use a blender to crush dandelion hay, weigh 1.0 g of the crushed dandelion hay sample into a beaker, soak the sample with 30 mL of ethanol with a volume fraction of 60 - 80%, vortex and mix evenly, and then put it into an ultrasonic-assisted extractor for extraction.

[0010] Further, in step (2), the decolorization treatment conditions are: adsorption time 5 h; sample loading concentration 30 mg / mL; sample loading volume 4 BV; eluent concentration 70%; eluent volume 6 BV.

[0011] Further, in step (2), the macroporous resin is D101 macroporous resin.

[0012] Further, in step (3), the ultrasonic-assisted antisolvent precipitation method is specifically as follows: Dissolve 0.02 g of chitosan in 10 mL of acetic acid solution with a volume fraction of 1%, and dissolve 0.1 g of zein in 10 mL of ethanol solution with a volume fraction of 70%; under the condition of uniform stirring, add the zein solution dropwise to the chitosan solution to prepare a Zein / CSNPs suspension; add the dandelion ethanol extract at a rotation speed of 1000 rmp, continuously stir for 1 h, and then perform ultrasonic treatment for 5 min until the solution state in the bottle is stable and uniform.

[0013] The nanomaterial for prolonging the fresh-keeping period of pork prepared by the above method is applied to the fresh-keeping of pork under sealed conditions at a certain temperature.

[0014] Further, the temperature is 4°C.

[0015] The nanomaterial for prolonging the fresh-keeping period of pork prepared by the above method is applied to the fresh-keeping of pork under non-sealed conditions at a certain temperature.

[0016] Further, the temperature is 4°C

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. By using the ultrasonic-assisted ethanol extraction technology and the macroporous resin adsorption and decolorization technology, the present invention significantly improves the purity and stability of the dandelion extract.

[0019] 2. The method provided by the present invention successfully prepares a nanomaterial (Zein / CS-DENPs) for prolonging the fresh-keeping period of pork, and optimizes its preparation process, so that the nanoparticles have good dispersibility and stability.

[0020] 3. In the fresh-keeping of pork, the nanomaterial (Zein / CS-DE NPs) for prolonging the fresh-keeping period of pork can effectively inhibit the growth of microorganisms, reduce the TVB-N and TBARS values, and maintain the color, texture characteristics and sensory quality of the meat.

[0021] 4. Compared with the existing preservation technologies, the nanomaterials of the present invention have a longer preservation period and better preservation effect, and the preparation process is simple, the cost is low, and it has good application prospects. Description of the Drawings

[0022] Figure 1 (a) is a comparison diagram of the appearance of dandelion extract before and after decolorization, Figure 1 (b) is an absorbance curve graph;

[0023] Figure 2 is a scanning electron microscope (SEM) image of Zein / CS-DE NPs;

[0024] Figure 3 is the pH change of the samples under non-sealed (A) and sealed (B) treatments;

[0025] Figure 4 is the change in redness value of the samples under different treatments (A1, A2, and A3 respectively represent the changes in redness value, yellowness value, and brightness value under non-sealed conditions; B1, B2, and B3 respectively represent the changes in redness value, yellowness value, and brightness value under sealed conditions);

[0026] Figure 5 is the change in total number of colonies of the samples under non-sealed (A) and sealed (B) treatments;

[0027] Figure 6 is the change in TVB-N value of the samples under non-sealed (A) and sealed (B) treatments;

[0028] Figure 7 is the change in TBARS value of the samples under non-sealed (A) and sealed (B) treatments;

[0029] Figure 8 is the change in hardness of the samples under non-sealed (A) and sealed (B) treatments;

[0030] Figure 9 is the change in elasticity of the samples under non-sealed (A) and sealed (B) treatments;

[0031] Figure 10 is the change in cohesiveness of the samples under non-sealed (A) and sealed (B) treatments;

[0032] Figure 11 is the change in chewiness of the samples under non-sealed (A) and sealed (B) treatments;

[0033] Figure 12 is the change in viscosity of the samples under non-sealed (A) and sealed (B) treatments;

[0034] Figure 13Appearance changes of non-sealed samples (14 days);

[0035] Figure 14 Appearance changes of sealed samples (18 days). Detailed implementation manners

[0036] The method of the present invention will be described in detail below in conjunction with specific embodiments and explanatory drawings. In the present invention, the nanomaterial for extending the fresh-keeping period of pork can be abbreviated as Zein / CS-DE NPs, zein can be abbreviated as Zein, chitosan can be abbreviated as CS, and the zein / chitosan suspension can be abbreviated as Zein / CS NPs suspension; the ethanol extract of dandelion can be abbreviated as DE; the zein (Chongqing Chaoyou Biotechnology Co., Ltd., product number ZY-203) and chitosan (Chongqing Chaoyou Biotechnology Co., Ltd., product number CS-105) used in the present invention.

[0037] I. Preparation method of a nanomaterial for extending the fresh-keeping period of pork

[0038] Example 1

[0039] A preparation method of a nanomaterial for extending the fresh-keeping period of pork includes the following steps:

[0040] (1) Preparation of dandelion extract: Using the ultrasonic-assisted ethanol extraction method, pulverize dandelion hay with a blender, weigh 1.0 g of the pulverized dandelion hay sample in a beaker, soak the sample with 30 mL of ethanol with a volume fraction of 70%, vortex mix and then put it into an ultrasonic-assisted extractor, and extract at a temperature of 60 °C for 60 min to obtain the ethanol extract of dandelion;

[0041] (2) Decolorization treatment of dandelion extract: Use macroporous resin adsorption to decolorize the above dandelion extract, with an adsorption time of 5 h; a loading concentration of 30 mg / mL; a loading volume of 3 BV; an eluent concentration of 70%; an eluent volume of 6 BV; Figure 1 (a) is a comparison diagram of the appearance of dandelion extract before and after decolorization, Figure 1 (b) is an absorbance curve graph, and the decolorization rate of macroporous resin for dandelion extract reaches 86.317%.

[0042] (3) Preparation of nanoparticles: Dissolve 0.02 g of chitosan in 10 mL of 1% acetic acid solution, and dissolve 0.1 g of zein in 10 mL of 70% ethanol solution; under the state of rapid stirring, add zein dropwise to the chitosan solution according to the mass ratio of 5:1 to prepare a zein / chitosan nanoparticles (Zein / CS NPs) suspension. Add the ethanol extract of dandelion obtained in step (2) at a rotation speed of 1000 rmp, continuously stir for 1 h, and then perform ultrasonic treatment for 5 min until the solution in the bottle is in a stable and uniform state.

[0043] Figure 2 Figure 4 is the scanning electron microscopy (SEM) image of Zein / CS-DE NPs. The SEM results show that Zein / CS-DE NPs have a rough spherical surface and form a relatively uniform pore structure.

[0044] Example 2

[0045] A preparation method of a nanomaterial for extending the shelf life of pork, comprising the following steps:

[0046] (1) Preparation of dandelion extract: Adopt the ultrasonic-assisted ethanol extraction method. Use a blender to crush dandelion hay, weigh 1.0 g of the crushed dandelion hay sample into a beaker, soak the sample with 30 mL of ethanol with a volume fraction of 60%, vortex and mix well, then put it into an ultrasonic-assisted extractor, and extract at 60 °C for 60 min to obtain the ethanol extract of dandelion.

[0047] (2) Decolorization treatment of dandelion extract: Adopt macroporous resin adsorption to decolorize the above dandelion extract. The adsorption time is 4 h; the sample loading concentration is 50 mg / mL; the sample loading volume is 4 BV; the eluent concentration is 60%; the eluent volume is 5 BV.

[0048] (3) Preparation of nanoparticles: Dissolve 0.02 g of chitosan in 10 mL of 1% acetic acid solution, and dissolve 0.1 g of zein in 10 mL of 70% ethanol solution; under the state of rapid stirring, add zein dropwise to the chitosan solution according to the mass ratio of 5:1 to prepare a zein / chitosan nanoparticles (Zein / CS NPs) suspension. Add the ethanol extract of dandelion obtained in step (2) at a rotation speed of 1000 rmp, continuously stir for 1 h, and then perform ultrasonic treatment for 5 min until the solution in the bottle is in a stable and uniform state.

[0049] Example 3

[0050] A preparation method of a nanomaterial for extending the shelf life of pork, comprising the following steps:

[0051] (1) Preparation of dandelion extract: The ultrasonic-assisted ethanol extraction method was adopted. The dandelion hay was crushed using a blender. 1.0 g of the crushed dandelion hay sample was weighed into a beaker, soaked with 30 mL of ethanol with a volume fraction of 80%. After vortex mixing, it was placed in an ultrasonic-assisted extractor and extracted at 60 °C for 60 min to obtain the dandelion ethanol extract;

[0052] (2) Decolorization treatment of dandelion extract: The above dandelion extract was decolorized by macroporous resin adsorption. The adsorption time was 4.5 h; the loading concentration was 40 mg / mL; the loading volume was 2 BV; the eluent concentration was 80%; the eluent volume was 7 BV;

[0053] (3) Preparation of nanoparticles: 0.02 g of chitosan was dissolved in 10 mL of 1% acetic acid solution, and 0.1 g of zein was dissolved in 10 mL of 70% ethanol solution; under the state of rapid stirring, zein was added dropwise to the chitosan solution according to a mass ratio of 5:1 to prepare a Zein / CS NPs suspension. The dandelion ethanol extract obtained in step (2) was added at a rotation speed of 1000 rmp. After continuous stirring for 1 h, it was treated with an ultrasonic machine for 5 min until the solution in the bottle was in a stable and uniform state.

[0054] II. Application of a nanomaterial for extending the shelf life of pork

[0055] 1) Application of Zein / CS-DE NPs in pork preservation under sealed conditions

[0056] Materials: Zein (Chongqing Chaoyou Biotechnology Co., Ltd., product number ZY-203), chitosan (Chongqing Chaoyou Biotechnology Co., Ltd., product number CS-105), dandelion ethanol extract (self-made in the laboratory).

[0057] Steps:

[0058] (1) Cut the pork tenderloin into uniform cubes of 2 cm × 2 cm × 1 cm and rinse with sterile water;

[0059] (2) Divide the meat cubes into four groups, namely Zein / CS-DE NPs group, DE group, and Zein / CS NPs group;

[0060] (3) Place the treated samples in fresh trays, seal them with PVC plastic wrap, and store them at 4 °C;

[0061] (4) Measure and evaluate the total number of colonies, pH value, TVB-N value, TBARS value, chromaticity, and texture of each group of samples at 0, 2, 4, 6, 8, 10, 12, 14, 16, and 18 days.

[0062] 2) Application of Zein / CS-DE NPs in the Fresh-keeping of Pork under Non-sealed Conditions

[0063] Materials: Zein (Chongqing Chaoyou Biotechnology Co., Ltd., product number ZY-203), chitosan (Chongqing Chaoyou Biotechnology Co., Ltd., product number CS-105), ethanol extract of dandelion (self-made in the laboratory).

[0064] Steps:

[0065] (1) Cut the pork tenderloin into uniform cubes of 2 cm×2 cm×1 cm and rinse with sterile water;

[0066] (2) Divide the meat cubes into four groups, namely Zein / CS-DE NPs group, DE group, Zein / CS NPs

[0067] (3) Place the treated samples in petri dishes and store them at 4°C;

[0068] (4) Measure and evaluate the total number of colonies, pH value, TVB-N value, TBARS value, chromaticity and texture of each group of samples at 0, 2, 4, 6, 8, 10, 12, and 14 days respectively.

[0069] 3) Test Results under Sealed and Non-sealed Conditions

[0070] Figure 3 Figure shows the pH changes of the samples under non-sealed (A) and sealed (B) treatments. It can be seen from the figure that with the increase of storage time, the pH value of the pork samples shows a trend of first decreasing and then increasing. Zein / CS-DE NPs can effectively slow down the increase of pH in pork. At the 14th day under non-sealed conditions, its pH value is still lower than the limit value of 6.2; under sealed conditions, at the 18th day, its pH value still remains at a relatively low level.

[0071] Figure 4 Figure shows the changes in redness values of the samples under different treatments (A1, A2, A3 represent the changes in redness value, yellowness value, and brightness value under non-sealed conditions respectively; B1, B2, B3 represent the changes in redness value, yellowness value, and brightness value under sealed conditions respectively). It can be seen from the figure that with the increase of storage time, the color of the pork has changed to varying degrees. The color difference value of the Zein / CS-DE NPs group is significantly lower than that of other groups, indicating that it can effectively maintain the color of the pork.

[0072] Figure 5For the change in the total number of colonies of samples under non-sealed (A) and sealed (B) treatments, it can be seen from the figure that as the storage time increases, the total number of colonies in the samples shows an upward trend. Zein / CS-DE NPs can effectively inhibit the growth of microorganisms. On the 14th day under non-sealed conditions, its total number of colonies is 97.97% lower than that of the blank control; under sealed conditions, on the 18th day, its total number of colonies is 98.29% lower than that of the blank control.

[0073] Figure 6 For the change in the TVB-N value of samples under non-sealed (A) and sealed (B) treatments, Zein / CS-DE NPs can effectively slow down the increase of the TVB-N value. On the 14th day under non-sealed conditions, its TVB-N value is 35.06% lower than that of the blank control; under sealed conditions, on the 18th day, its TVB-N value is 27.77% lower than that of the blank control.

[0074] Figure 7 For the change in the TBARS value of samples under non-sealed (A) and sealed (B) treatments, it can be seen from the figure that Zein / CS-DENPs can effectively inhibit lipid oxidation. On the 14th day under non-sealed conditions, its TBARS value is 38.56% lower than that of the blank control; under sealed conditions, on the 18th day, its TBARS value is 29.50% lower than that of the blank control.

[0075] Figures 8 - 12 For the graphs of the changes in hardness, elasticity, cohesiveness, chewiness, and adhesiveness of samples under non-sealed (A) and sealed (B) treatments, it can be seen from the figure that the Zein / CS-DE NPs group can better maintain the texture characteristics of pork. On the 14th day under non-sealed conditions, the decrease in its hardness, elasticity, cohesiveness, and chewiness is significantly lower than that of the blank group; under sealed conditions, on the 18th day, its texture characteristics are still well maintained.

[0076] Figure 13 For the appearance change (14 days) of the non-sealed treated samples, it can be seen from the figure that when stored at 4°C in the refrigerator for 14 days, the appearance of the non-sealed samples changes significantly: signs of spoilage began to appear in the blank group and the DE group on the 13th day, while severe water loss occurred in the Zein / CS NPs group, with the surface being dry, shrunken, and yellowed. In contrast, the Zein / CS-DE NPs group still maintained a good appearance on the 13th day, with little color change, and only slight spoilage and water loss occurred until the 14th day, indicating that its fresh-keeping effect under non-sealed conditions can reach 13 days.

[0077] Figure 14For the appearance changes of the sealed samples (18 days), it can be seen from the figure that when stored for 18 days under sealed conditions, obvious spoilage occurred in the blank group and the DE group on the 17th day, with a pungent odor and white sticky secretions appearing on the surface of the meat slices. The Zein / CS-DE NPs group still maintained a good appearance on the 17th day, and the color and moisture were close to the initial state, and only slight changes occurred until the 18th day, indicating its significant fresh-keeping effect under sealed conditions and extending the fresh-keeping period to 18 days.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A preparation method of a nanomaterial for prolonging the freshness preservation period of pork, characterized in that, It includes the following steps: (1) Preparation of dandelion extract: Using the ultrasonic-assisted ethanol extraction method, mix dandelion powder with ethanol with a volume fraction of 60 - 80% at a solid-liquid ratio of 1:30, extract at 60 °C for 60 min to obtain the dandelion ethanol extract; (2) Decolorization treatment of dandelion extract: Use macroporous resin to decolorize the above dandelion extract, with an adsorption time of 4 - 5 h; the loading concentration is 30 - 50 mg / mL; the loading volume is 2 - 4 BV; the eluent concentration is 60 - 80%; the eluent volume is 5 - 7 BV; (3) Preparation of nanoparticles: Dissolve zein and chitosan at a mass ratio of 5:1 in ethanol, add 30 mg / mL of the dandelion ethanol extract obtained in step (2), stir evenly, and then use the ultrasonic-assisted antisolvent precipitation method.

2. The preparation method of the nanomaterial for prolonging the shelf life of pork according to claim 1, characterized in that, In step (1), the ultrasonic-assisted ethanol extraction method is specifically as follows: Use a blender to crush dandelion hay, weigh 1.0 g of the crushed dandelion hay sample in a beaker, soak the sample with 30 mL of ethanol with a volume fraction of 60 - 80%, vortex mix, and then put it into an ultrasonic-assisted extractor for extraction.

3. According to claim 1, for prolonging the preservation of pork in step (2), the decolorization treatment conditions are: adsorption time 5 h; loading concentration 30 mg / mL; loading volume 4 BV; eluent concentration 70%; eluent volume 6 BV.

4. The preparation method of the nanomaterial for prolonging the fresh-keeping period of pork according to claim 1, characterized in that, In step (2), the macroporous resin is D101 macroporous resin.

5. The preparation method of the nanomaterial for prolonging the fresh-keeping period of pork according to claim 1, characterized in that, In step (3), the ultrasonic-assisted antisolvent precipitation method is specifically as follows: Dissolve 0.02 g of chitosan in 10 mL of acetic acid solution with a volume fraction of 1%, and dissolve 0.1 g of zein in 10 mL of ethanol solution with a volume fraction of 70%; under the condition of uniform stirring, slowly add the zein solution dropwise to the chitosan solution to prepare a Zein / CS NPs suspension; add the dandelion ethanol extract at a rotation speed of 1000 rmp, continuously stir for 1 h, and then ultrasonically treat for 5 min until the solution in the bottle is in a stable and uniform state.

6. Application of a nanomaterial for prolonging the shelf life of pork, characterized in that, Preserve pork with the nanomaterial prepared by the method of claims 1 - 5 under sealed conditions at a certain temperature.

7. The application of the nanomaterial for prolonging the shelf life of pork according to claim 6, characterized in that The temperature is 4 °C.

8. Application of a nanomaterial for prolonging the fresh-keeping period of pork, characterized in that, Preserve pork with the nanomaterial prepared by the method of claims 1 - 5 under non-sealed conditions at a certain temperature.

9. The application of the nanomaterial for prolonging the fresh-keeping period of pork according to claim 8, wherein, The temperature is 4 °C.

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