A pretreatment method for fish glue products and fish glue semi-finished products obtained by the pretreatment method

Abstract

The present invention belongs to the field of food processing technology and specifically relates to a pretreatment method for fish gelatin products, a semi-finished fish gelatin product obtained by the pretreatment method, and an instant fish gelatin product using the semi-finished fish gelatin product as a raw material. The present invention provides a pretreatment method for fish gelatin products that can effectively improve the stability of foamed fish gelatin during heat sterilization. The method can control the hydration rate (mass loss rate) of the foamed fish gelatin after sterilization at 121°C for 20 minutes to less than 10%, while maintaining a good taste (texture), reaching the leading level in the fish gelatin industry (the current industry level is a hydration rate generally exceeding 40%).

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a pretreatment method for fish glue products and a fish glue semi-finished product obtained by the pretreatment method, and also relates to instant fish glue using the fish glue semi-finished product as a raw material. Background Art

[0002] Isinglass is the dried product of fish maw (the organ used by fish to adjust their sinking and floating, also known as fish bladder). Rich in gelatin, it's also known as fish maw or fish maw. Along with bird's nest and shark fin, isinglass is one of the "Eight Delicacies" and is known as the "Ginseng of the Sea." Its main ingredients are high-grade collagen, multiple vitamins, and trace elements such as calcium, zinc, iron, and selenium. With a protein content of 84.2% and a fat content of only 0.2%, it is an ideal high-protein, low-fat food.

[0003] Traditionally, fish maw is primarily cooked directly or processed into dried products for sale on the market. However, these dried products require cumbersome steps such as washing, soaking, and steaming before consumption, significantly limiting the development of fish maw products. In recent years, with rising health awareness, the scale of my country's fish maw industry has expanded year by year, and the deep processing of fish maw has also developed rapidly, resulting in the development of a variety of products such as fish maw beverages, fish maw meat cakes, flavored fish maw slices, and puffed fish maw crisps. Among these, ready-to-eat fish maw holds the largest market share and is the most popular among consumers. Ready-to-eat fish maw is a jelly-like product made by sterilizing the semi-finished fish maw at high temperature and then stewing it with other ingredients.

[0004] High-temperature sterilization is a critical step in the processing of ready-to-eat fish maw. During the sterilization process, the high temperatures often cause fish maw products to become soft and rotten, resulting in a poor taste. Hardness, viscosity, and shear force directly impact the taste of fish maw products. Differences in hardness and shear force may be related to the degree of collagen degradation in fish maw. The fish maw protein content of several common fish species is over 70%, of which the collagen content is over 60%. When collagen is subjected to intense heat (heating temperature above the deformation temperature), hydrogen bonds are easily broken, causing degradation and precipitation. The heat deformation temperature of fish maw collagen in common fish is 30-45°C, while the sterilization temperature of fish maw is generally around 121°C. When sterilized at this temperature, the collagen is affected by the high temperature, absorbing water and swelling, becoming soft, resulting in a decrease in mechanical strength. While its solubility increases, it continuously degrades into gelatin and precipitates, making the surface sticky and increasing its viscosity. Fish maw exhibits severe hydration and texture collapse after high-temperature sterilization. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a pretreatment method for fish gelatin products and a fish gelatin semi-finished product obtained by the pretreatment method, so as to solve the problem that foamed fish gelatin undergoes severe hydration and texture collapse after high-temperature sterilization.

[0006] In order to achieve the above object, the solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a method for pretreating fish glue products, comprising the following steps:

[0008] soaking the dried fish glue in a foaming solution for foaming, wherein the foaming solution includes a protein biological cross-linking agent;

[0009] Soak the expanded fish glue in the curdlan polysaccharide solution.

[0010] Preferably, the protein biocrosslinking agent is one or more selected from transglutaminase (TGase), polyphenol oxidase and peroxidase, preferably transglutaminase (TGase).

[0011] Preferably, the enzyme activity of the protein biocrosslinking agent is 5-20 U / ml.

[0012] Preferably, the mass concentration of the curdlan polysaccharide solution is 1%-10%, preferably 1%-5%, more preferably 1%-3%.

[0013] Preferably, before soaking the dried fish glue in the foaming liquid for foaming, the method further comprises: steaming the dried fish glue for 10-15 minutes; preferably, the method further comprises: steaming the dried fish glue for 10-15 minutes and then stewing for 5-10 minutes.

[0014] Preferably, the soaking temperature of the dried fish glue in the foaming liquid is 20-30° C., and the soaking time is 12-24 hours.

[0015] Preferably, during the foaming process, ultrasonic treatment is performed once per hour for 5-15 minutes each time, with an ultrasonic power of 120-400 W and an ultrasonic frequency of 40 kHz.

[0016] Preferably, after soaking the dried fish glue in the foaming liquid for foaming, the method further comprises: washing the foamed fish glue and freezing it at -20°C for 8-15 hours, and then thawing it at 4°C for 12-24 hours.

[0017] Preferably, the step of soaking the expanded fish gelatin in the curdlan polysaccharide solution comprises: soaking the thawed fish gelatin in the curdlan polysaccharide solution for 5-15 minutes, boiling it at 100° C. for 5-15 minutes, taking it out and soaking it in cold water, repeating the soaking-boiling-cooling process 3-5 times, and the soaking temperature is 20-30° C.

[0018] In a second aspect, the present invention further provides a semi-finished fish glue product obtained by the pretreatment method of fish glue products as described above.

[0019] In a third aspect, the present invention further provides an instant fish glue, wherein the raw materials for preparing the instant fish glue include the semi-finished fish glue product as described above.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention provides a pretreatment method for fish glue products, which can effectively improve the stability of foamed fish glue during heat sterilization. The method can control the hydration rate (mass loss rate) of the foamed fish glue within 10% after sterilization at 121°C for 20 minutes, and can maintain a good taste (texture), reaching the leading level in the fish glue related industry (the current industry level is that the hydration rate generally exceeds 40%). DETAILED DESCRIPTION

[0022] The present invention provides a method for pretreating fish glue products, comprising the following steps:

[0023] Step (1), immersing the dried fish glue in a foaming liquid for foaming.

[0024] In one embodiment of the present invention, the foaming solution includes a protein biocrosslinking agent, and the protein biocrosslinking agent is selected from one or more of transglutaminase (TGase), polyphenol oxidase and peroxidase, preferably transglutaminase (TGase).

[0025] Transglutaminase (TGase) is a monomeric protein with an active center and a molecular weight of about 38,000, which is composed of 331 amino groups. It can catalyze the intramolecular and intermolecular covalent cross-linking of protein polypeptides, thereby improving the structure and function of proteins. It has a significant effect on the properties of proteins such as foaming, emulsification, emulsion stability, thermal stability, water retention and gelling ability, thereby improving the flavor, mouthfeel, texture and appearance of foods such as fish glue and bird's nest. In the present invention, the addition of transglutaminase (TGase) can increase the density of the internal protein network structure of fish glue. The dense internal protein network structure can better lock in moisture, making fish glue less likely to lose water, dissolve and hydrate during high-temperature sterilization. At the same time, the dense internal network structure can also well improve the collapse of fish glue caused by high-temperature sterilization, and can significantly improve the stability and product quality of fish glue products during high-temperature sterilization.

[0026] In the present invention, the addition amount of glutamine transaminase (TGase) is 0.1wt%-10wt% of the dry fish gelatin (for example, 0.1wt%-9wt%, 0.1wt%-8wt%, 0.1wt%-7wt%, 0.1wt%-6wt%, 0.1wt%-5wt%, 0.1wt%-4wt%, 0.1wt%-3wt%, 0.1wt%-2wt%, 0.1wt%-1wt%, 0.1 wt%-0.5wt%, 1wt%-10wt%, 1wt%-9wt%, 1wt%-8wt%, 1wt%-7wt%, 1wt%-6wt%, 1wt%-5wt%, 1wt%-4 wt%, 1wt%-3wt%, 1wt%-2wt%, 2wt%-10wt%, 2wt%-9wt%, 2wt%-8wt%, 2wt%-7wt%, 2wt%-6wt%, 2wt% -5wt%, 2wt%-4wt%, 2wt%-3wt%, 3wt%-10wt%, 3wt%-9wt%, 3wt%-8wt%, 3wt%-7wt%, 3wt%-6wt%, 3 wt%-5wt%, 3wt%-4wt%, 4wt%-10wt%, 4wt%-9wt%, 4wt%-8wt%, 4wt%-7wt%, 4wt%-6wt%, 4wt%-5wt% ,5wt%-10wt%,5wt%-9wt%,5wt%-8wt%,5wt%-7wt%,5wt%-6wt%,6wt%-10wt%,6wt%-9wt%,6wt%- 8wt%, 6wt%-7wt%, 7wt%-10wt%, 7wt%-9wt%, 7wt%-8wt%, 8wt%-10wt%, 8wt%-9wt%, 9wt%-10wt%).

[0027] In one embodiment of the present invention, the dried fish glue may be steamed for 10-15 minutes before being immersed in the foaming liquid for foaming, or the dried fish glue may be steamed for 10-15 minutes and then stewed for 5-10 minutes.

[0028] In one embodiment of the present invention, the dry fish glue is immersed in the foaming liquid for foaming at a temperature of 20-30°C and a foaming time of 12-24 hours. In a preferred embodiment, during the foaming process, ultrasonic treatment is performed once per hour for 5-15 minutes each time, with an ultrasonic power of 120-400W and an ultrasonic frequency of 40kHz. Ultrasonic treatment can increase the porosity of the internal structure of the fish glue, thereby increasing the permeability and permeation uniformity of transglutaminase (TGase) in the aqueous phase inside the fish glue, achieving efficient covalent cross-linking of the collagen inside the fish glue by transglutaminase (TGase), and assisting in increasing the density of the protein network inside the fish glue.

[0029] Step (2), washing the expanded fish glue, freezing it at -20°C for 8-15 hours, and then thawing it at 4°C for 12-24 hours.

[0030] During this freeze-thaw treatment step, the permeability and permeation uniformity of transglutaminase (TG enzyme) in the aqueous phase inside fish gelatin can be further increased, and the degree of covalent cross-linking of collagen inside fish gelatin by transglutaminase (TG enzyme) can be further improved, thereby helping to increase the density of the protein network inside fish gelatin.

[0031] Step (3) is to soak the thawed fish glue in the curdlan polysaccharide solution for 5-15 minutes, boil it at 100°C for 5-15 minutes, take it out and soak it in cold water, and repeat the soaking-boiling-cooling process 3-5 times, with the soaking temperature being 20-30°C.

[0032] In the present invention, the curdlan polysaccharide solution employed is a solution of curdlan gum dissolved in water or a solvent. Curdlan gum is a non-toxic, odorless, microbially fermented polysaccharide. It is a homopolysaccharide, a linear glucan formed by connecting D-glucose subunits with β-1,3-glycosidic bonds and lacking side chains. Curdlan gum has unique gelling properties. Depending on the heating temperature, curdlan gum can form two completely different types of gels: heating a curdlan aqueous suspension to approximately 55°C forms a thermoreversible gel, while heating to above 80°C forms a thermoirreversible gel.

[0033] Therefore, the present invention soaks the thawed fish glue in a curdlan polysaccharide solution for 5-15 minutes, boils it at 100°C for 5-15 minutes, takes it out and soaks it in cold water, so that a thermally irreversible gel coating layer can be formed on the surface of the fish glue. The coating layer has a water-proof and heat-insulating effect, physically isolates the fish glue from the external water environment, and blocks heat transfer between the fish glue and the external environment to a certain extent, thereby protecting the fish glue from damage during high-temperature sterilization and hydrating it.

[0034] Step (4): Finally, the fish glue is vacuum-packed to obtain a fish glue semi-finished product that can be used as a raw material for instant fish glue.

[0035] The present invention will be further described below in conjunction with the examples. The various raw materials used in the present invention are all commercially available food raw materials. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. For those skilled in the art, without departing from the concept of the present invention, several modifications and improvements can also be made. All equivalent conversions made using the present invention's description, or direct or indirect applications in other related technical fields, are included in the scope of protection of the present invention's patent.

[0036] Example:

[0037] This embodiment provides a pretreatment method for fish gelatin products that can solve the problem of severe hydration and texture collapse of foamed fish gelatin after high-temperature sterilization, comprising the following steps:

[0038] First, steam the dried fish maw for 10 minutes and then simmer for 5 minutes. Then, immerse it in a soaking solution and store it at 20-30°C for 12-24 hours. Ultrasonicate once every hour for 10 minutes at a power of 120-400W and a frequency of 40kHz. The soaking solution contains TGase with an activity of 5-20U / ml. After soaking, wash the fish maw and freeze it at -20°C for 12 hours. Thaw it at 4°C for 12-24 hours. Soak the thawed fish maw in a curdlan polysaccharide solution for 5-15 minutes, boil it at 100°C for 10 minutes, remove it, and soak it in cold water. Repeat this soaking-boiling-cooling process 3-5 times. The curdlan polysaccharide solution has a concentration of 1%-5% and the soaking temperature is 20-30°C. Finally, vacuum-pack the fish maw.

[0039] The vacuum-packed fish glue is placed in a sterilizer and sterilized at 121°C for 20 minutes. After the temperature drops to room temperature, the sterilizer is opened, the package is unpacked and the fish glue is taken out, the surface moisture is wiped dry and the intact fish glue after removing the hydrated part is weighed. The hydration rate is calculated according to the following formula: Hydration rate (%) = (1-weight of intact fish glue after sterilization / weight of intact fish glue before sterilization) × 100%.

[0040] The present invention also conducted an orthogonal experiment (as shown in Table 1) using vacuum packaging, enzyme cross-linking during the expansion process, freeze-thaw treatment, ultrasonic treatment, and curdlan polysaccharide solution treatment as variable factors to further illustrate the superiority of the pretreatment method of the fish gelatin product of the present invention.

[0041] Table 1 Effects of different pretreatment methods on the stability of fish glue after high temperature sterilization (121℃, 20min)

[0042]

[0043] Note: The ultrasonic frequency used was 40 Hz and the ultrasonic time was 60 min.

[0044] From Table 1 we can see that:

[0045] 1. Vacuum packaging can improve hydration to a certain extent, and the hydration rate dropped from 53.7% in the control group to 47.9%, so vacuum packaging was used in subsequent studies.

[0046] 2. TG enzyme treatment can also improve the hydration situation to a certain extent. After pre-treatment with the optimized enzyme treatment conditions (10 U / ml, 25°C, 4 hours), the hydration rate can be reduced to 40.1%. However, the overall hydration situation is still serious, and the texture is severely damaged, which cannot meet the product quality requirements of the production and sales links.

[0047] 3. We tried to improve the hydration of gelatin by freeze-thaw plus ultrasonic treatment. The results showed that freeze-thaw plus ultrasonic treatment can further significantly reduce the hydration rate. The best hydration rate can be reduced to about 25% (freeze-thaw once at -20℃ plus ultrasonic treatment for 60 minutes) (ultrasound conditions: 240W, 40Hz);

[0048] 4. In order to control the hydration rate of fish glue during high-temperature sterilization to a lower level to meet the requirements of production cost and product quality, the present invention innovatively uses a method of forming a heat-irreversible gel layer on the surface of fish glue using a curdlan polysaccharide solution to improve the stability of fish glue during high-temperature sterilization. Experiments have found that this method can significantly further reduce the hydration of fish glue. The gel coating layer formed by soaking in a 2% curdlan polysaccharide solution can control the hydration rate of fish glue after heat sterilization to within 10%, reaching the industry-leading level (the current industry level is that the hydration rate generally exceeds 40%).

[0049] Best embodiment:

[0050] The following is the best embodiment based on the pretreatment conditions of sample 9 in Table 1.

[0051] Step 1) Weigh about 50 grams of Vietnamese low-eyed toothless fish glue, put it into a stainless steel steamer heated by an induction cooker, steam it over high heat for 10 minutes (put in the glue after the water boils and start the time), and then continue to simmer for 5 minutes;

[0052] Step 2), immersing the fish glue after step 1) in a foaming solution containing 10 U / mL cross-linking enzyme and placing it at 25° C. for 12 hours; during the foaming period, the fish glue is ultrasonically treated once every hour for 10 minutes each time, with an ultrasonic power of 120 W and a frequency of 40 kHz;

[0053] Step 3) Wash the fish glue treated in step 2) with water three times and wipe it dry, put it into the freezer at -20°C for 12 hours, take it out, put it into a refrigerator at 4°C to fully thaw, and wipe off the surface moisture;

[0054] Step 4) Soak the completely thawed fish glue in a 2% curdlan polysaccharide solution for 10 minutes (soaking temperature 25°C), then take it out and put it into boiling water at 100°C and keep boiling for 10 minutes, then take it out and soak it in cold water to cool it. Repeat this soaking-boiling-cooling process 3 times;

[0055] Step 5), packing the fish glue processed in step 4) into packaging bags and then vacuumizing;

[0056] Step 6) Place the vacuum-packed fish glue in step 5) into a sterilizer and sterilize at 121° C. for 20 minutes. After the temperature drops to room temperature, open the sterilizer, unpack and take out the fish glue, wipe off the surface moisture, weigh the intact fish glue after removing the hydrated part, and calculate the hydration rate.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for pretreating fish glue products, characterized in that: The steps include: The dried fish glue is immersed in a foaming solution for foaming, and during the foaming process, ultrasonic treatment is performed once every hour for 5-15 minutes each time, with an ultrasonic power of 120-400W and an ultrasonic frequency of 40kHz; the foaming solution includes a protein biocrosslinker, and the protein biocrosslinker is TG enzyme; Wash the soaked fish glue and freeze it at -20℃ for 8-15h, then thaw it at 4℃ for 12-24h. The thawed fish glue is soaked in the curdlan polysaccharide solution for 5-15 minutes, boiled at 100°C for 5-15 minutes, taken out and immersed in cold water, and the soaking-boiling-cooling process is repeated 3-5 times, and the soaking temperature is 20-30°C.

2. The pretreatment method of fish glue products according to claim 1, wherein The enzyme activity of the protein biological cross-linking agent is 5-20 U / ml.

3. The pretreatment method of fish glue products according to claim 1, wherein The mass concentration of the curdlan polysaccharide solution is 1%-10%.

4. The pretreatment method of fish glue products according to claim 1, characterized in that, Before soaking the dried fish glue in the foaming liquid, the process also includes: steaming the dried fish glue for 10-15 minutes.

5. The pretreatment method of fish glue products according to claim 4, characterized in that, The dry fish glue is immersed in the foaming liquid for foaming at a temperature of 20-30°C and a foaming time of 12-24 hours.

6. The pretreatment method of fish glue products according to any one of claims 1 to 5, characterized in that: The last step also includes vacuum packaging of fish glue.

7. A semi-finished fish glue product obtained by the pretreatment method of fish glue products according to any one of claims 1 to 6.

8. A ready-to-eat fish glue, characterized in that The raw materials for preparing the instant fish glue include the fish glue semi-finished product according to claim 7.

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