阅读说明：本技术 一种冰鲜大黄鱼的保藏方法 (Preservation method of iced fresh large yellow croaker ) 是由 翁武银 黄莉 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种冰鲜大黄鱼的保藏方法,包括如下步骤：将含有明胶的电解水通过浇筑和冷却制备成电解水凝胶薄片,将捕捞的大黄鱼经碎冰冷却致死、分级、利用盐水冰冷却后,再采用一层电解水凝胶薄片一层鱼进行冷藏,最后封装在泡沫箱中,用冷藏车运送至全国批发市场进行销售。本发明由于采用电解水凝胶对冷藏大黄鱼进行保鲜,可以大幅度延长大黄鱼的冰鲜保质期。(The invention discloses a preservation method of iced fresh large yellow croakers, which comprises the following steps: pouring and cooling electrolyzed water containing gelatin to prepare an electrolyzed hydrogel sheet, crushing and cooling the caught large yellow croaker to death, grading, refrigerating the large yellow croaker layer by using brine ice, finally packaging the large yellow croaker layer by layer in a foam box, and transporting the large yellow croaker layer by using a refrigerator car to national wholesale markets for sale. The invention adopts the electrolytic hydrogel to keep the refrigerated large yellow croaker fresh, so that the fresh-keeping period of the large yellow croaker can be greatly prolonged.)

1. A preservation method of ice fresh large yellow croaker is characterized in that: the method comprises the following steps:

s1, preparing electrolytic hydrogel: preparing a gelatin NaCl aqueous solution into electrolytic water by using a nano catalytic free radical generator, and preparing an electrolytic hydrogel sheet with the thickness of 2-4 cm by pouring and cooling to-2 ℃;

s2, preparing the slightly frozen large yellow croaker: freezing the caught large yellow croaker to death, grading, and preparing the frozen fresh large yellow croaker by using brine ice;

s3, electrolytic hydrogel preservation: the large yellow croaker is packaged by the electrolytic hydrogel and then is packaged in a foam box and stored in a refrigerator at 4 ℃ or is transported to wholesale markets across the country by using a refrigerator truck.

2. The preservation method of frozen fresh large yellow croaker according to claim 1, wherein: in step S1, the gelatin and NaCl aqueous solution is added to the NaCl aqueous solution, and then swelled at room temperature for 30-60 min, and then dissolved in a water bath at 60 ℃, and cooled to room temperature to prepare electrolytic water, wherein the gelatin and NaCl aqueous solution has a gelatin mass concentration of 3-5% and a NaCl mass concentration of 1-3%.

3. The preservation method of frozen fresh large yellow croaker according to claim 1, wherein: in step S1, the electrolytic water containing gelatin is prepared under the following conditions: the current is 4-9A, the flow rate is 3-5L/min, the electrolysis time is 30-60 min, and the content of chloride ions in the electrolyzed water reaches 200-400 mg/kg.

4. The preservation method of frozen fresh large yellow croaker according to claim 1, wherein: in step S2, the saline ice is crushed ice prepared by using 1% -3% saline water, and the temperature of the saline ice is-1 ℃ to-3 ℃.

5. The preservation method of frozen fresh large yellow croaker according to claim 1, wherein: in step S3, the method for wrapping large yellow croaker with electrolytic hydrogel includes: one layer of the electrolytic hydrogel and one layer of the slightly frozen large yellow croaker are stacked for 3-5 layers.

Technical Field

The invention belongs to the technical field of fish preservation, and particularly relates to the technical field of preservation of iced fresh large yellow croakers.

Background

The large yellow croaker is warm-temperature offshore cluster migratory fish, mainly inhabits the middle and lower layers of coastal and offshore water areas, is one of the four traditional marine products in China, and is also important marine cultured fish in China. The large yellow croaker is golden and attractive in color, tender and delicious in meat quality, rich in unsaturated fatty acids such as EPA and DHA, high in protein, low in cholesterol and the like, and deeply favored by consumers. The culture yield of the large yellow croakers in 2019 reaches 22.5 ten thousand tons, and 83 percent of the large yellow croakers are concentrated in fujianningde. At present, large yellow croaker is mainly circulated in the market in the form of frozen fresh and frozen products. However, the frozen large yellow croaker has poor fish meat quality and cannot meet the requirements of consumers. The frozen and fresh large yellow croakers are mostly transported to national wholesale markets for sale by using a refrigerator car after being cooled by crushed ice, the ice is melted into water in the transportation process and can also cause cross contamination, and meanwhile, the skins of the fish bodies are easily damaged due to collision in the transportation process, microorganisms easily invade the fish bodies and are easy to decay and deteriorate. Moreover, the single refrigeration and preservation can only inhibit the activity of microorganisms to a certain extent, and the shelf life of the product is short.

The subacid electrolyzed water is prepared by electrolyzing NaCl solution with certain concentration through a diaphragm-free electrolyzed water generator, and the generated electrolyzed water contains Cl-containing sterilization factors such as [ Cl ], HClO, ClO < - >, and the like. Wherein the neutral HClO can penetrate the mucus layer, cell wall and protective layer of microorganism, kill bacteria by changing the permeability of cell membrane, oxidizing sulfhydryl-containing enzyme group and preventing protein synthesis, and has 80 times of antibacterial ability of ClO-. In addition, the slightly acidic electrolyzed water also has the characteristics of low pH value and high ORP value, and can destroy the cell membrane potential of microorganisms, change the electron current and the membrane permeability, thereby leading to the interruption of the metabolic flux and ATP synthesis and leading the microorganisms to die. The three components act together to make the slightly acidic electrolyzed water have higher disinfection and sterilization effects. The subacid electrolyzed water not only has high-efficiency and broad-spectrum bactericidal performance, but also is converted into common water after being used, has less influence on the environment, has the advantages of safety, environmental protection, low cost, easy preparation and the like, and is a novel bactericide which is green, environment-friendly, safe and reliable.

The invention prepares the electrolyzed water into hydrogel, and can prolong the preservation period of the refrigerated large yellow croaker.

Disclosure of Invention

The invention aims to provide a preservation method of iced fresh large yellow croakers, which is a method for preparing electrolytic hydrogel by cooling an electrolytic aqueous solution containing gelatin and utilizing the electrolytic hydrogel to preserve the iced fresh large yellow croakers.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the invention relates to a method for preserving iced fresh large yellow croakers, which comprises the following steps:

s1, preparing electrolytic hydrogel: preparing a gelatin NaCl aqueous solution into electrolytic water by using a nano catalytic free radical generator, and preparing electrolytic hydrogel with the thickness of 2-4 cm by pouring and cooling to-2 ℃;

s2, preparing the slightly frozen large yellow croaker: freezing the caught large yellow croaker to death, grading, and preparing the frozen fresh large yellow croaker by using brine ice;

s3, electrolytic hydrogel preservation: the large yellow croaker is packaged by the electrolytic hydrogel and then is packaged in a foam box and stored in a refrigerator at 4 ℃ or is transported to wholesale markets across the country by using a refrigerator truck.

Further, in step S1, the gelatin and NaCl aqueous solution is added to the NaCl aqueous solution, and the mixture is swelled at room temperature for 30-60 min, dissolved in a water bath at 60 ℃, and cooled to room temperature to prepare the electrolyzed water, wherein the gelatin mass concentration in the gelatin and NaCl aqueous solution is 3-5% and the NaCl mass concentration is 1-3%.

Further, in step S1, the electrolytic water is prepared under the following conditions: the current is 4-9A, the flow rate is 3-5L/min, the electrolysis time is 30-60 min, and the content of chloride ions in the electrolyzed water reaches 200-400 mg/kg.

Further, in the step S2, the saline ice is crushed ice prepared by using 1% -3% of saline water, and the temperature of the saline ice is-1 ℃ to-3 ℃.

Further, in step S3, the method for wrapping large yellow croaker with electrolytic hydrogel includes: one layer of the electrolytic hydrogel and one layer of the slightly frozen large yellow croaker are stacked for 3-5 layers.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. when the large yellow croaker is refrigerated by crushed ice, the skin of the large yellow croaker body is easily damaged due to collision in the transportation process, and microorganisms invade the large yellow croaker body to cause putrefaction and deterioration. The invention adopts the electrolytic water solution containing the gelatin to prepare the gel to replace crushed ice for preserving the large yellow croaker, can avoid the damage to the skin caused by severe collision of the large yellow croaker in the transportation process, can also slowly release the Cl-containing bactericidal factor, kill the putrefactive microorganisms on the surface of the large yellow croaker, inhibit the growth and the propagation of the microorganisms and further prolong the preservation effect.

2. During transportation, the temperature rises slightly, ice melts into water, and cross contamination between large yellow croakers can be caused. The invention adopts the electrolytic hydrogel, which can not melt water at the temperature below 15 ℃, and can avoid cross contamination among large yellow croaker individuals.

3. The electrolytic hydrocolloid prepared by the method is sterilized at 80-90 ℃, then is prepared into electrolytic water by using a nano catalytic free radical generator, and can be prepared into electrolytic hydrogel for repeated use by cooling, so that the use cost is reduced.

The invention will now be further described with reference to the accompanying tables and specific examples.

Drawings

FIG. 1 shows the change of total number of colonies (Log (CFU/g)) in a cold storage process of large yellow croaker.

Detailed Description

Example 1

Experimental group

S1, adding 300 g of fish scale gelatin into 10L of NaCl solution with the mass concentration of 1%, swelling for 60 min at 20 ℃, heating for 60 min in a water bath at 60 ℃, cooling to room temperature, electrolyzing for 60 min by using a nano catalytic free radical generator at the current of 9A and the flow rate of 3L/min to prepare electrolyzed water, pouring the electrolyzed water with the chloride ion concentration of about 200 mg/L into a foam box, cooling to 2 ℃, and standing for a period of time to prepare the electrolyzed hydrogel with the thickness of 2 cm.

S2, crushing, cooling and grading the caught large yellow croaker, and cooling the large yellow croaker by using brine ice which is prepared by using 1% brine and has the temperature of-1 ℃ to prepare the micro-frozen large yellow croaker.

And S3, stacking the large yellow croakers for 3 layers in a manner of using a layer of electrolytic hydrogel sheet to slightly freeze the large yellow croakers, sealing the uppermost layer with the electrolytic hydrogel, finally sealing in a foam box, and storing in a refrigerator at 4 ℃.

Control group

S1, freezing and grading the caught large yellow croaker to death by broken ice, and freezing the large yellow croaker by using brine ice which is prepared by 1% brine and has the temperature of-1 ℃ to prepare the micro-frozen large yellow croaker.

S2, stacking the large yellow croakers for 3 layers in a way of crushing ice one layer by one layer and slightly freezing the large yellow croakers, sealing the uppermost layer with the crushed ice, finally packaging in a foam box, and storing in a refrigerator at 4 ℃.

Example 2

Experimental group

S1, adding 400 g of fish scale gelatin into 10L of NaCl solution with the mass concentration of 2%, swelling for 45 min at 25 ℃, heating for 60 min in a water bath at 60 ℃, cooling to room temperature, electrolyzing for 45 min by using a nano catalytic free radical generator at the current of 4A and the flow rate of 5L/min to prepare electrolyzed water, pouring the electrolyzed water with the chloride ion concentration of about 300 mg/L into a foam box, cooling to 0 ℃, and standing for a period of time to prepare the electrolyzed hydrogel with the thickness of 3 cm.

S2, crushing, cooling and grading the caught large yellow croaker, and cooling the large yellow croaker by using brine ice which is prepared by using 2% brine and has the temperature of-2 ℃ to prepare the micro-frozen large yellow croaker.

And S3, stacking the large yellow croakers for 4 layers in a manner of using a layer of electrolytic hydrogel sheet to slightly freeze the large yellow croakers, sealing the uppermost layer with the electrolytic hydrogel, finally sealing in a foam box, and storing in a refrigerator at 4 ℃.

Control group

S1, freezing and grading the caught large yellow croaker to death by broken ice, and freezing the large yellow croaker by using brine ice which is prepared by 2% of brine and has the temperature of-2 ℃ to prepare the micro-frozen large yellow croaker.

S2, stacking the large yellow croakers for 4 layers in a way of crushing ice one layer by one layer and slightly freezing the large yellow croakers, sealing the uppermost layer with crushed ice, finally packaging in a foam box, and storing in a refrigerator at 4 ℃.

Example 3

Experimental group

S1, adding 500 g of fish scale gelatin into 10L of NaCl solution with the mass concentration of 3%, swelling for 30 min at 30 ℃, heating for 60 min in a water bath at 60 ℃, cooling to room temperature, electrolyzing for 60 min by using a nano catalytic free radical generator at the current of 9A and the flow rate of 3L/min to prepare electrolyzed water, pouring the electrolyzed water with the chloride ion concentration of about 400 mg/L into a foam box, cooling to-2 ℃, standing for a period of time to prepare the electrolyzed hydrogel with the thickness of 4 cm.

S2, crushing, cooling and grading the caught large yellow croaker, and cooling the large yellow croaker by using brine ice which is prepared by using 3% brine and has the temperature of-3 ℃ to prepare the micro-frozen large yellow croaker.

And S3, stacking the large yellow croakers for 5 layers in a manner of using a layer of electrolytic hydrogel sheet to slightly freeze the large yellow croakers for one layer, sealing the uppermost layer by using the electrolytic hydrogel, finally sealing the uppermost layer in a foam box, and storing the foam box in a refrigerator at the temperature of 4 ℃.

Control group

S1, freezing and grading the caught large yellow croaker to death by broken ice, and freezing the large yellow croaker by using brine ice which is prepared by 1% brine and has the temperature of-3 ℃ to prepare the micro-frozen large yellow croaker.

S2, stacking the large yellow croakers for 5 layers in a mode of crushing ice one layer by one layer and slightly freezing the large yellow croakers, sealing the uppermost layer with the crushed ice, finally packaging in a foam box, and storing in a refrigerator at 4 ℃.

Example 4

Determination of Total colony count (TVC)

5 g of large yellow croaker fish meat samples of the experimental group and the control group in the above examples 1 to 3 were respectively mixed with 95 ml of sterile physiological saline (0.85% NaCl solution), homogenized for 5 min by beating with a homogenizer (MiniMix 100, Interscience, France), diluted 10 times with sterile physiological saline, poured into a culture dish by a plate casting method, 1 ml of diluent with appropriate concentration was poured into the culture dish, mixed with plate count agar, and cultured at 30 ℃ for 48 h to calculate the total number of colonies, and the results are shown in FIG. 1.

As can be seen from figure 1, compared with the traditional crushed ice refrigeration and preservation, the preservation time can be obviously prolonged by utilizing the electrolytic hydrogel slice prepared by the invention to wrap the large yellow croaker for refrigeration and preservation. As can be seen from example 1, the total number of colonies preserved for 20 days in the experimental group is close to the total number of colonies preserved for 12 days in the control group, indicating that the shelf life of refrigerated large yellow croaker can be prolonged by using the electrolytic hydrogel sheet for 8 days. Although the initial cooling temperature of the large yellow croaker (control group) can reduce the growth and propagation of microorganisms to some extent, the total number of colonies of the large yellow croaker exceeds the acceptable upper limit value (6 logs (CFU/g)) after 12 days of refrigeration. However, as the concentration of available chlorine in the electrolytic hydrogel sheet increased, a significant decrease in the total number of colonies of large yellow croaker was observed (experimental group), and the experimental group of example 3 was kept at an acceptable upper limit (6 log (CFU/g)) after 20 days. The results show that the refrigerated preservation of the large yellow croaker by using the electrolytic hydrogel slice prepared by the invention can greatly prolong the refrigerated shelf life of the large yellow croaker.

And the used electrolytic hydrocolloid is sterilized at 80-90 ℃, then is prepared into electrolytic water by using a nano catalytic free radical generator, can be prepared into electrolytic hydrogel by cooling, can be used for keeping fresh of the frozen fresh large yellow croaker, and has the effect of repeated use times mainly depending on the thermal degradation degree of gelatin protein molecules. When the alpha subunit in the gelatin is completely degraded, the use effect of the electrolytic hydrogel is reduced.

In conclusion, the electrolytic hydrogel slice is prepared by pouring and cooling the electrolytic water containing the gelatin, and the frozen fresh pseudosciaena crocea is refrigerated by adopting one layer of electrolytic hydrogel slice and one layer of pseudosciaena crocea, so that the frozen fresh shelf life of the pseudosciaena crocea can be greatly prolonged.

Although specific embodiments of the invention have been described above, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the appended claims.