CN111227026B - A kind of method that utilizes shrimp and crab shells to prepare meat fresh-keeping film - Google Patents

Abstract

The invention discloses a method for preparing a meat preservative film by using shrimp and crab shells, which solves the problem that the existing chitosan preservative film has unsatisfactory preservative effect. Which comprises the following steps: (1) pretreatment of raw materials: s1, preparing chitin nano particles; s2, preparing fig emulsion; (2) mixing materials; (3) degassing; and (4) film formation. Specifically, the method comprises the steps of carrying out hydrothermal treatment on shrimp and crab shells, modifying chitin in the shrimp and crab shells, carrying out hydrothermal amino modification, stripping impurities except the chitin by using ultrasonic waves, preparing chitin antibacterial nano ions by crosslinking with polyphosphate, combining fig emulsion with acetic acid and glycerol, carrying out homogenization crosslinking reaction, preparing a film by using a film blowing or film liquid casting technology, and drying to obtain a product. The materials of the invention are all selected from natural raw materials, and the prepared meat preservative film is safe and green, has excellent packaging performance and good antibacterial property, and effectively ensures the antibacterial effect and shelf life.

Description

A kind of method that utilizes shrimp and crab shell to prepare meat preservative film

technical field

The invention relates to the manufacture of films or sheets containing macromolecular substances, in particular to a method for preparing meat fresh-keeping film by utilizing shrimp and crab shells.

Background technique

With the improvement of people's quality of life, people's consumption concept has changed from focusing on quantity to new concepts such as quality, safety, greenness and health. Meat and its products are susceptible to microbial contamination and other environmental factors, causing spoilage. The safety of meat and its products has attracted widespread attention. Therefore, how to extend the shelf life of meat and its products is an urgent problem to be solved. question.

At present, in order to achieve the purpose of extending the shelf life of food, plastic wrap has entered thousands of households and has become a must-have good product at home. Commercially available cling film products are all made of vinyl masterbatch and are divided into three types of cling film: PE, PVC and PVDC. Among them, PVC is harmful to the human body, because it contains plasticizers, etc., which will migrate to food when heated or oiled. Chemical composition, causing carcinogenic effect after human consumption. Therefore, people urgently need safe, green and healthy plastic wrap. There are preservative films prepared from chitosan on the market, but the preservative films made of chitosan have certain defects. Chitosan itself has poor moisture resistance and anti-ultraviolet properties, and the effect of coating on preservative films is poor. The technology and formulation of chitosan to prepare plastic wrap are in urgent need of innovation and breakthrough. In addition, the extraction process of chitosan from shrimp and crab shells is complex, and the quality of chitosan products limits the development of plastic wrap.

How to use the resource of shrimp and crab shells to prepare high-efficiency meat cling film products has become a hot spot for technical personnel to explore.

SUMMARY OF THE INVENTION

In order to overcome the deficiency that the existing chitosan fresh-keeping film has an unsatisfactory fresh-keeping effect, the object of the present invention is to provide a method for preparing meat fresh-keeping film by using shrimp and crab shells. In this method, the shrimp and crab shells are subjected to hydrothermal treatment to modify the chitin contained in the shrimp and crab shells, modify the amino groups, and at the same time use ultrasonic waves to strip off impurities such as calcium salts and denatured proteins, and modify the cross-linking of chitin and polyphosphate to prepare antibacterial products. Nano-ion, combined with fig emulsion, combined with acetic acid and glycerin, fully homogenized for cross-linking reaction, using membrane liquid casting technology to make a film, and drying to obtain a fresh-keeping film product. The meat preservative film prepared by the invention has excellent packaging performance and good antibacterial performance.

The technical solution adopted by the present invention to solve the technical problem is: a method for preparing meat preservative film using shrimp and crab shells, which is characterized in that: it undergoes the following process steps:

(1) Raw material pretreatment

S1. Preparation of chitin nanoparticles: Weigh dried shrimp and crab shells, add distilled water, then put them in a muffle furnace at 150-200°C, perform constant temperature hydrothermal treatment for 10-15 hours, and use an ultrasonic cell pulverizer to process them for 10-10 hours after taking them out. After 15 minutes, add polyphosphate, homogenize with a homogenizer for 10-15 minutes, let it stand for 3-5 minutes, remove the precipitate, centrifuge the remaining suspension, take the precipitate after centrifugation, and obtain chitin nanoparticles for later use;

S2. Preparation of fig emulsion: Weigh the autumn fruit of fig, centrifuge after crushing, take the upper milky liquid to obtain fig emulsion, and set aside;

(2) Mixing: Weigh the chitin nanoparticles obtained in step (1) S1 and the fig emulsion obtained in step (1) S2 and mix them in proportion, add acetic acid aqueous solution, add chitin nanoparticles, fig emulsion and acetic acid at the same time Glycerin with a total weight of 1-3% of the aqueous solution is stirred to a homogeneous liquid at a temperature of 30-40°C;

(3) Degassing: Place the homogeneous liquid obtained in step (2) under vacuum and at room temperature, and shake it with an ultrasonic cell pulverizer for 15-25 minutes to remove air bubbles in the homogeneous liquid;

(4) Film making: The degassed homogeneous liquid obtained in step (3) is made into a film by film blowing or film liquid casting technology, and dried at a temperature of 40-50°C to obtain a meat preservation film .

As a preferred aspect of the present invention, in the step (1) S1, the muffle furnace is provided with a nitrogen working environment by a nitrogen filling device, and the conditions of the nitrogen working environment of the muffle furnace are: nitrogen pressure 4～ 6MPa, flow rate 10-13kg/h.

As a preferred aspect of the present invention, in the step (1) S1, the processing conditions of the ultrasonic cell pulverizer: power 10-20KHz, nitrogen working environment.

As a preferred aspect of the present invention, in the step (1) S1, the weight ratio of the shrimp and crab shells to distilled water is 1:3-5, and the amount of polyphosphate added is 1-3% of the total weight of distilled water.

As a preferred aspect of the present invention, in the step (1) S1, the polyphosphate is preferably tripolyphosphate.

As a preferred aspect of the present invention, in the step (1) S2, the autumn fig fruit is a fruit grown for 35-45 days in autumn.

As a preferred aspect of the present invention, in the step (2), the weight ratio of the chitin nanoparticles to the fig emulsion is 1:0.2-0.5; the added amount of the acetic acid aqueous solution is and 2 to 5% of the total weight of the fig emulsion.

As a preferred aspect of the present invention, the concentration of the aqueous acetic acid solution is 1-3%.

The present invention aims at the characteristics of the negative charge on the surface of the microorganism, utilizes the positive charge carried by the plastic wrap to interact with the negative charge of the microorganism, adsorbs to the cell membrane, enters into the cell through endocytosis, and interacts with it physically or chemically, thereby affecting the life of the cell. Physiological activities, and finally achieve the purpose of preservation. In the present invention, it adopts hydrothermal modification of chitin in shrimp and crab shells to synthesize amino-functionalized chitin in one step, so that it has antibacterial and antibacterial properties, and removes impurities such as calcium carbonate and denatured proteins through ultrasonic waves, and through physical purification. The green and functional chitin material was obtained, and the nano-chitosan particles with stable performance and remarkable antibacterial effect were prepared by using the N-P ion cross-linking method; at the same time, the natural antibacterial fig emulsion was selected to improve the nanoshell through synergistic antibacterial and cross-linking The film-forming performance of polysaccharide particles improves its antibacterial breadth and effect. The materials of the invention are all collected from natural raw materials without introducing any chemical components. The prepared meat preservation film is safe and green, and has excellent packaging performance. The biocompatibility of chitosan ensures the tightness of the contact surface with meat , effectively guarantee the antibacterial effect and shelf life, and have broad application prospects for meat preservation.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments, and the described examples are helpful for the understanding and implementation of the present invention, and are not intended to limit the present invention.

If not specified, the polyphosphate used in the implementation of the present invention is sodium tripolyphosphate.

Example 1

A kind of method that utilizes shrimp and crab shell to prepare meat preservation film, it goes through the following process steps:

(1) Raw material pretreatment

S1. Preparation of chitin nanoparticles: Weigh dried shrimp and crab shells, add distilled water, wherein the weight ratio of shrimp and crab shells to distilled water is 1:4, then put them into a muffle furnace at 180°C, and conduct constant temperature hydrothermal treatment for 12 hours. And the muffle furnace is provided with a nitrogen working environment by a nitrogen filling device. The conditions of the nitrogen working environment of the muffle furnace are: nitrogen pressure 5MPa, flow rate 12kg/h; Conditions: power 15KHz, nitrogen environment; after crushing, add polyphosphate, the amount of polyphosphate added is 2.5% of the total weight of shrimp and crab shells and distilled water, homogenize with a homogenizer for 12 minutes, let stand for 4 minutes, remove the precipitate, The remaining suspension was centrifuged, and the precipitate after centrifugation was taken to obtain chitin nanoparticles for subsequent use;

S2. Preparation of fig emulsion: Weigh the autumn fruit of fig, which is a fruit grown for 40 days in autumn, centrifuge after crushing, take the upper milky liquid to obtain fig emulsion, and set aside;

(2) Mixing: Weigh the chitin nanoparticles obtained in step (1) S1 and the fig emulsion obtained in step (1) S2 and mix them in a weight ratio of 1:0.3, then add chitin nanoparticles and fig emulsion 3% acetic acid aqueous solution with a total weight of 2%, and the concentration of the acetic acid aqueous solution is 2%; at the same time, add chitin nanoparticles, fig emulsion and glycerin with a total weight of 2.5% of the acetic acid aqueous solution, and stir until a homogeneous liquid at a temperature of 35°C ;

(3) Degassing: Place the homogeneous liquid obtained in step (2) under vacuum and at room temperature, and shake it with an ultrasonic cell pulverizer for 20 minutes to remove air bubbles in the homogeneous liquid;

(4) Film production: the degassed homogeneous liquid obtained in step (3) is made into a film by film casting technology, and dried at a temperature of 45°C to obtain a meat preservation film.

Example 2

A kind of method that utilizes shrimp and crab shell to prepare meat preservation film, it goes through the following process steps:

(1) Raw material pretreatment

S1. Preparation of chitin nanoparticles: Weigh dried shrimp and crab shells, add distilled water, wherein the weight ratio of shrimp and crab shells to distilled water is 1:3, then put them into a muffle furnace at 150°C, and conduct constant temperature hydrothermal treatment for 10 hours. And the muffle furnace is provided with a nitrogen working environment by a nitrogen filling device. The conditions of the nitrogen working environment of the muffle furnace are: nitrogen pressure 4MPa, flow rate 10kg/h; Treatment conditions: power 10KHz, nitrogen environment; add polyphosphate after crushing treatment, the amount of polyphosphate added is 1% of the total weight of shrimp and crab shells and distilled water, homogenize with a homogenizer for 10 minutes, let stand for 3 minutes, and remove sediment , the remaining suspension was centrifuged, and the centrifuged precipitate was obtained to obtain chitin nanoparticles for subsequent use;

S2. Preparation of fig emulsion: Weigh the autumn fruit of fig, which is a fruit grown for 35 days in autumn, centrifuge after crushing, take the upper milky liquid to obtain fig emulsion, and set aside;

(2) Mixing: Weigh the chitin nanoparticles obtained in step (1) S1 and the fig emulsion obtained in step (1) S2 and mix them in a weight ratio of 1:0.2, then add chitin nanoparticles and fig emulsion Acetic acid aqueous solution with a total weight of 2%, and the concentration of the aqueous acetic acid solution is 1%; at the same time, add chitin nanoparticles, fig emulsion and glycerol with a total weight of 1.5% of the aqueous acetic acid solution, and stir until a homogeneous liquid is obtained at a temperature of 30°C ;

(3) Degassing: place the homogeneous liquid obtained in step (2) under vacuum and at room temperature, and shake it with an ultrasonic cell pulverizer for 15 minutes to remove air bubbles in the homogeneous liquid;

(4) Film making: The degassed homogeneous liquid obtained in step (3) is made into a film by film blowing technology, and dried at a temperature of 40°C to obtain a meat preservation film.

Example 3

A kind of method that utilizes shrimp and crab shell to prepare meat preservation film, it goes through the following process steps:

(1) Raw material pretreatment

S1. Preparation of chitin nanoparticles: Weigh dried shrimp and crab shells, add distilled water, wherein the weight ratio of shrimp and crab shells to distilled water is 1:5, then put them in a muffle furnace at 200°C, and conduct constant temperature hydrothermal treatment for 15 hours. And the muffle furnace is provided with a nitrogen working environment by a nitrogen filling device. The conditions of the nitrogen working environment of the muffle furnace are: nitrogen pressure 6MPa, flow rate 13kg/h; Conditions: power 20KHz, nitrogen environment; after crushing, add polyphosphate, the amount of polyphosphate added is 3% of the total weight of shrimp and crab shells and distilled water, homogenize with a homogenizer for 15 minutes, let stand for 5 minutes, remove the precipitate, The remaining suspension was centrifuged, and the precipitate after centrifugation was taken to obtain chitin nanoparticles for subsequent use;

S2. Preparation of fig emulsion: Weigh the autumn fruit of fig, which is a fruit grown for 45 days in autumn, centrifuge after crushing, take the upper milky liquid to obtain fig emulsion, and set aside;

(2) Mixing: Weigh the chitin nanoparticles obtained in step (1) S1 and the fig emulsion obtained in step (1) S2 and mix them in a weight ratio of 1:0.5, then add chitin nanoparticles and fig emulsion Acetic acid aqueous solution with a total weight of 5%, and the concentration of the aqueous acetic acid solution is 3%; at the same time, add chitin nanoparticles, fig emulsion and glycerol with a total weight of 3% of the aqueous acetic acid solution, and stir until a homogeneous liquid is obtained at a temperature of 40°C ;

(3) Degassing: place the homogeneous liquid obtained in step (2) in a vacuum at room temperature, and shake it with an ultrasonic cell pulverizer for 25 minutes to remove air bubbles in the homogeneous liquid;

(4) Film production: the degassed homogeneous liquid obtained in step (3) is made into a film by film casting technology, and dried at a temperature of 50°C to obtain a meat preservation film.

Comparative Example 1

In this comparative example, its preparation method is basically the same as that of Example 1, with the difference that: no muffle furnace is used to hydrothermally treat shrimp and crab shells in step (1) S1.

Comparative Example 2

In this comparative example, its preparation method is basically the same as in Example 1, the difference being that no ultrasonic cell pulverizer treatment is performed in step (1) S1.

Comparative Example 3

In this comparative example, its preparation method is basically the same as that of Example 1, the difference being that no polyphosphate ion cross-linking treatment is performed in step (1) S1.

Comparative Example 4

In this comparative example, its preparation method is basically the same as that of Example 1, the difference being that the operation of adding fig emulsion in step (1) is not performed in S2.

Comparative Example 5

In this comparative example, its preparation method is basically the same as that of Example 1, the difference being that the chitin nanoparticles and fig emulsion are replaced with chitosan in step (2) without step (1).

1. Preservative film characteristic test

The above-mentioned Examples 1 to 3 and Comparative Examples 1 to 5 were tested for properties such as stretchability of plastic wrap, elongation at break and oxygen permeability coefficient. The detection method implemented the latest national plastic wrap inspection standard, and the results are shown in Table 1. .

Table 1 Comparison of properties of plastic wrap under different treatment conditions

From the comparison of Examples 1 to 3 in Table 1 and Comparative Examples 1 to 5, it can be seen that the fresh-keeping film prepared by shrimp and crab shells without hydrothermal treatment and ultrasonic treatment to remove impurities is fragile and easy to crack, with small elongation at break and good oxygen permeability. The coefficient is very large; without polyphosphate ionic cross-linking, all indicators are weakened, and the oxygen permeability coefficient is particularly affected; the addition of fig emulsion significantly improves the stretchability, elongation at break and oxygen permeability coefficient of the plastic wrap. The synergistic effect can better improve the characteristics of the synthetic plastic wrap, and the effect of the plastic wrap with shrimp and crab shells as the main raw material is better than that of the plastic wrap with chitosan as the main raw material.

Analysis of microbial changes and TBA value changes over time in fresh pork treated with plastic wrap

2. Preservation film preservation test

Get the fresh pork tenderloin, cut it into about 100g meat pieces with a high-temperature sterilized cutter, divide 27 samples, place the fresh pork sample in the aseptic room to dry the surface at normal temperature, then wrap and seal with the preservative film of the present invention, Refrigerate in a fresh-keeping cabinet at 0-5°C, measure thiobarbituric acid and microorganisms on the 1st, 3rd, 6th, 9th, 12th, and 15th day, and test 3 parallels for each sample, of which 3 pieces are used for the first Determination of initial indicators of fresh pork once.

Evaluation standard: Thiobarbituric acid (TBA) standard: the maximum TBA value of fresh meat is 0.7 ~ 1 mg/g, if it exceeds, it is considered to have oxidative rancidity and cannot be eaten; microbiological standard: according to China's pollution-free food standard Judgment of the total number of colonies in fresh meat: less than 1×10 ⁴ colonies/g for fresh meat, 1×10 ⁴ to 1×10 ⁶ colonies/g for sub-fresh meat, and more than 1×10 ⁶ colonies/g for spoiled meat. The measurement results are shown in Table 2.

Table 2 The total number of microorganisms (expressed in logarithmic value, lg value) and TBA value (MDA, mg/g) changes during storage

The data of table 2 shows, and embodiment 1～3 shows that fresh pork is under the effect of fresh-keeping film of the present invention, still keeps the total number of bacterial colonies in the range of fresh meat on the 6th day, enters the sub-new meat range on the 9th day, and is still in the range of fresh meat until the 15th day. The range of sub-fresh meat, while utilizing the preservative film prepared by Comparative Example 1-4 to process fresh pork, it has entered the range of secondary fresh meat on the 6th day, and exceeded the range of secondary fresh meat on the 15th day, becoming spoiled meat, The fresh pork treated with the plastic wrap obtained in Comparative Example 5 was spoiled meat on the 12th day. The above results show that operations such as hydrothermal treatment, ultrasonic impurity removal, ion cross-linking and the addition of fig milk have effectively improved the fresh-keeping performance of the plastic wrap, and their synergistic effect can effectively reduce microbial contamination. The preservation period of fresh pork proves that the present invention effectively improves the defects that chitosan preservation film exists. And show in TBA value data, embodiment 1-3 TBA value is still less than 0.7, illustrates that the fresh pork is still not spoiled in the 15th day, can also eat, and this is consistent with the total number of microorganisms result. However, the fresh pork treated with plastic wrap prepared in Comparative Examples 1-4 had a TBA value greater than 1 in the 15th day in Comparative Examples 1 and 2, and became spoiled meat, while the other Comparative Examples were all less than 1 and could still be eaten. The above TBA value shows that hydrothermal treatment, ultrasonic impurity removal and fig emulsion significantly affect the oxygen barrier performance of the plastic wrap, which is consistent with the results of the oxygen permeability coefficient in Table 1. Compared with Comparative Example 5, the penetration of oxygen is significantly prevented. All the results show that The fresh-keeping film provided by the invention has better fresh-keeping effect.

3. Water retention test of plastic wrap

Because the moisture content of fresh pork changes with time, the detection test of the moisture content of fresh pork treated with plastic wrap was carried out according to GB/T 9695.15 Meat and meat product moisture content determination operation, the results are shown in Table 3.

Moisture content (%) in the fresh pork of table 3

test group 1 day 3 days 6 days 9 days 12 days 15 days Example 1 75.41 75.41 75.13 74.92 74.72 74.35 Example 2 75.41 75.41 75.38 75.19 75.01 74.84 Example 3 75.41 75.41 75.09 74.84 74.6 74.42 Comparative Example 1 75.41 75.01 74.42 74 73.65 73.11 Comparative Example 2 75.41 75.41 75.25 74.83 74.66 74.23 Comparative Example 3 75.41 75.41 75.01 74.62 74.26 73.74 Comparative Example 4 75.41 75.11 74.69 74.25 73.86 73.3 Comparative Example 5 75.41 75.41 75.21 74.93 74.65 74.22

The data in Table 3 shows that Examples 1 to 3 show that the preservative film prepared by the present invention loses about 0.75%-1.41% of water during the storage of fresh pork, which shows that the preservative film provided by the present invention has good water resistance and can effectively prevent Evaporation of water in the meat quality reduces the quality of fresh pork. Compared with Comparative Example 5, the present invention has better water retention performance. Comparative examples 1 to 4 show that hydrothermal treatment, ion crosslinking and fig emulsion have a significant impact on the water retention of the plastic wrap, and their synergistic effect effectively improves the water retention of the plastic wrap material.

Claims (5)

1. A method utilizing shrimp and crab shells to prepare meat preservative film is characterized in that: it passes through the following processing steps: (1) Raw material pretreatment S1. Preparation of chitin nanoparticles: Weigh dried shrimp and crab shells, add distilled water, then put them in a muffle furnace at 150-200°C, perform constant temperature hydrothermal treatment for 10-15 hours, and use an ultrasonic cell pulverizer to process them for 10-10 hours after taking them out. After 15 minutes, add polyphosphate, homogenize with a homogenizer for 10-15 minutes, let it stand for 3-5 minutes, remove the precipitate, centrifuge the remaining suspension, take the precipitate after centrifugation, and obtain chitin nanoparticles for later use; S2. Preparation of fig emulsion: Weigh the autumn fruit of fig, centrifuge after crushing, take the upper milky liquid to obtain fig emulsion, and set aside; (2) Mixing: Weigh the chitin nanoparticles obtained in step (1) S1 and the fig emulsion obtained in step (1) S2 and mix them in proportion, add acetic acid aqueous solution, add chitin nanoparticles, fig emulsion and acetic acid at the same time Glycerin with a total weight of 1-3% of the aqueous solution is stirred to a homogeneous liquid at a temperature of 30-40°C; (3) Degassing: Place the homogeneous liquid obtained in step (2) under vacuum and at room temperature, and shake it with an ultrasonic cell pulverizer for 15-25 minutes to remove air bubbles in the homogeneous liquid; (4) Film making: The degassed homogeneous liquid obtained in step (3) is made into a film by film blowing or film liquid casting technology, and dried at a temperature of 40-50°C to obtain a meat preservation film ;in, In the step (1) S1, the weight ratio of the shrimp and crab shells to the distilled water is 1:3-5, and the amount of the polyphosphate added is 1-3 of the total weight of the shrimp and crab shells and the distilled water. %; Described polyphosphate is tripolyphosphate; In the step (2), the weight ratio of the chitin nanoparticles and the fig emulsion is 1:0.2-0.5; the amount of the acetic acid aqueous solution is 2% of the total weight of the chitin nanoparticles and the fig emulsion. ~5%; The concentration of the acetic acid aqueous solution is 1-3%. 2. A method for preparing meat preservative film using shrimp and crab shells according to claim 1, characterized in that: in the step (1) S1, the muffle furnace is supplied with nitrogen gas by a nitrogen gas filling device working environment. 3. A method for preparing meat preservative film using shrimp and crab shells according to claim 2, characterized in that: the conditions of the nitrogen working environment of the muffle furnace: nitrogen pressure 4 ~ 6MPa, flow rate 10-13kg /h. 4. A method for preparing meat preservative film using shrimp and crab shells according to claim 1, characterized in that: in the step (1) S1, the processing conditions of the ultrasonic cell pulverizer: power 10～20KHz, nitrogen working environment. 5. A method for preparing meat preservative film using shrimp and crab shells according to claim 1, characterized in that: in the step (1) S2, the autumn fruit of the fig grows for 35-45 Fruit of the day.