CN116473109A

CN116473109A - Phosphorus-free water-retaining agent for frozen fish slices and preparation method and application thereof

Info

Publication number: CN116473109A
Application number: CN202310468567.0A
Authority: CN
Inventors: 周云峰; 林性; 黄良杰
Original assignee: Hainan Yunfu Fishery Co ltd
Current assignee: Hainan Yunfu Fishery Co ltd
Priority date: 2023-04-27
Filing date: 2023-04-27
Publication date: 2023-07-25

Abstract

The invention provides a phosphorus-free water-retaining agent for frozen fish slices, and a preparation method and application thereof, wherein the phosphorus-free water-retaining agent comprises the following raw materials in parts by weight: 10-25 parts of trehalose, 0.3-1.5 parts of chitosan, 0.3-1.2 parts of L-arginine, 2-6 parts of sodium citrate, 2-6 parts of konjak fine powder, 1-3 parts of sesbania gum, 2-5 parts of compound protein peptide and 0.9-1.5 parts of towel gourd concentrated solution, and the raw materials are scientifically proportioned, enter the fish meat through osmosis, increase the space between muscle bundles and between myofibrils by deep expansion, increase the space for keeping internal moisture, form a network structure in space, enhance the stability of the structure, make the thawed and cooked tilapia meat have white color, luster, no obvious other colors, unique delicious taste, no fishy smell, moderate salty taste, strong juice feel, compact tissue structure, firmness, flat section, no air hole, good elasticity and moderate softness and hardness.

Description

Phosphorus-free water-retaining agent for frozen fish slices and preparation method and application thereof

Technical Field

The invention relates to the field of aquatic product processing, in particular to a phosphorus-free water-retaining agent for frozen fish slices, and a preparation method and application thereof.

Background

The traditional minced fillet water-retaining agent is mainly polyphosphate, can effectively improve the tenderness of products, improve the texture and the flavor, has good water-retaining performance, and is widely applied in the food industry. However, since phosphates are easily hydrolyzed, it is difficult to maintain a good water-retaining effect for a long time. In addition, the addition of excess phosphate causes unpleasant metallic astringency of the product and tends to cause rough texture, surface "crystallization" and the like in the surimi. The frozen fish slices have reduced water holding quality with increased storage time, increased juice loss during thawing and heating, quality loss, and reduced quality such as hardened meat, fragile meat, roughened mouthfeel, darkened appearance, etc.

Disclosure of Invention

In view of the above, the invention provides a phosphorus-free water-retaining agent for frozen fish fillets, and a preparation method and application thereof, and solves the problems.

The technical scheme of the invention is realized as follows: the phosphorus-free water-retaining agent for frozen fish slices comprises the following raw materials in parts by weight: 10-25 parts of trehalose, 0.3-1.5 parts of chitosan, 0.3-1.2 parts of L-arginine, 2-6 parts of sodium citrate, 2-6 parts of konjak fine powder, 1-3 parts of sesbania gum, 2-5 parts of compound protein peptide and 0.9-1.5 parts of towel gourd concentrated solution.

Further, the phosphorus-free water-retaining agent for frozen fish slices comprises the following raw materials in parts by weight: 17 parts of trehalose, 0.9 part of chitosan, 0.7 part of L-arginine, 4 parts of sodium citrate, 4 parts of konjak fine powder, 2 parts of sesbania gum, 3 parts of compound protein peptide and 0.6 part of towel gourd concentrated solution.

Further, the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 1-3:2-5:0.3-2.

Further, the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 1-3m pieces ² Soaking in boiling water for 10-15min, filtering, taking out, adding enzyme solution, mixing with the weight/volume ratio g/mL of the towel gourd fragments and enzyme solution of 1-3:20, stirring and mixing for 2-6min, storing for 3-5 days in dark place, suction filtering, pulverizing filter cake, sieving with 300-400 mesh sieve, adding 70-90% ethanol solution with the weight/volume ratio g/mL of the filter cake powder and ethanol solution of 2-10:50, transferring into rotary evaporator, rotary evaporating and concentrating at 70-90deg.C to 1/3-5 of original volume, discharging, standing, and cooling to obtain the concentrated solution of towel gourd.

Furthermore, the enzyme solution is added with cellulase accounting for 1.0 to 1.36 percent of the mass of the towel gourd fragments and neutral proteinase accounting for 1.2 to 2.25 percent of the mass of the towel gourd fragments into clear water.

Further, the preparation method of the phosphorus-free water-retaining agent for frozen fish slices comprises the following steps:

s1, mixing and stirring trehalose, chitosan and L-arginine to obtain a mixed material I;

s2, adding sodium citrate and konjak fine powder into the mixture I, and uniformly mixing and stirring to obtain a mixture II;

s3, adding sesbania gum and compound protein peptide into the mixture II, slowly adding deionized water, raising the temperature to 40-65 ℃, and stirring while adding to obtain viscous liquid;

s4, adding the luffa concentrated solution into the viscous liquid, continuously stirring for 1-5min, performing ultrasonic dispersion for 40-60min, and freeze-drying to obtain the phosphorus-free water-retaining agent.

Further, the stirring speed is 400-600rpm, and the mixing and stirring time of S3 is 15-30min.

Further, the ultrasonic power of the S4 is 2500-3500W, and the ultrasonic frequency is 20-100KHz.

Furthermore, the phosphorus-free water-retaining agent is applied to frozen aquatic products.

Further, the application comprises the following steps:

a) Knocking live fish at 10deg.C to kill, removing head, tail, scales and viscera, washing blood stain with sterile water, and air drying;

b) Slicing muscle at back of fish, soaking fish slices with specification of 3cm×3cm×3mm in water-retaining agent for 20-40min, and slowly stirring every 5 min;

c) After soaking, sucking up the surface water of the fish slices, and freeze-preserving at the temperature below-20 ℃.

Compared with the prior art, the invention has the beneficial effects that:

the water-retaining agent disclosed by the invention is reasonably screened in components, scientifically proportioned, enters the inside of fish meat through osmosis, and utilizes deep expansion to increase the space between muscle bundles and between muscle fibrils, increase the space for retaining internal moisture, form a network structure in space and enhance the stability of the structure;

trehalose is combined with myofibrillar protein to enhance stability of myoglobulin and prevent myoglobulin-white denaturation; the complex protein peptide and the lysate with high molecular weight can adsorb and retain a large amount of water and pass Ca on the surface of fish meat ²⁺ 、Mg ²⁺ Plasma forms gel film to prevent internal water loss; the chitosan forms an edible film on the surface of the fish meat to reduce the loss of water, thereby achieving the effect of water retention; l-arginine is a basic amino acid with an isoelectric point of 10.76, and can improve the pH value of meat, so that the pH value deviates from the isoelectric point of protein, and the water holding capacity of the meat is improved; the sodium citrate can improve the water holding capacity and stability of the fish meat, improve the texture and tenderness of the fish meat, firmly combine the lipid, the water and other components in the fish meat with muscle tissues to form a compact structure, reduce the loss of nutrients and flavor substances in the preservation process, and combine the konjak fine powder and sesbania gum with salt-soluble proteins in the fish meat to form a good network structure, so as to play a role in stabilizing cell membranes and protein structures, thereby greatly improving the water holding capacity and tissue state of the fish meat; the compound protein peptide micromolecules permeate into the fish muscle, maintain the osmotic pressure of the muscle, reduce the water activity of the fish muscle, effectively prevent the deformation of muscle protein and stabilize the protein molecular space structure; the hydrophobic part on the towel gourd concentrated solution can be combined with the hydrophobic group in the shrimp protein, so that the hydrophobic part on the surface of the muscle is closed, and the hydrophilic part replaces the hydrophobic area in the original fish meat, so that more water molecules can be combined, the water retention effect is greatly improved, and the thawing loss rate is low.

Detailed Description

In order to better understand the technical content of the present invention, the following provides specific examples to further illustrate the present invention.

The experimental methods used in the embodiment of the invention are conventional methods unless otherwise specified.

Materials, reagents, and the like used in the examples of the present invention are commercially available unless otherwise specified.

Example 1

The phosphorus-free water-retaining agent for frozen fish slices comprises the following raw materials in parts by weight: trehalose 10 parts, chitosan 0.3 parts, L-arginine 0.3-parts2 parts of sodium citrate, 2 parts of konjak fine powder, 1 part of sesbania gum, 2 parts of compound protein peptide and 0.9 part of towel gourd concentrated solution; the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 1:2:0.3; the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 1m pieces ² Adding the fragments into boiling water, soaking for 10min, filtering, taking out, adding enzyme solution, stirring and mixing for 2min, storing for 3 days in dark, filtering, pulverizing filter cake, sieving with 300 mesh sieve, adding 70% ethanol solution, mixing with 2:50 of the filter cake powder and the ethanol solution, rotary evaporating at 70deg.C, concentrating to 1/3 of the original volume, discharging, standing, and cooling to obtain concentrated solution.

Example 2

The phosphorus-free water-retaining agent for frozen fish slices comprises the following raw materials in parts by weight: 25 parts of trehalose, 1.5 parts of chitosan, 1.2 parts of L-arginine, 6 parts of sodium citrate, 6 parts of konjak fine powder, 3 parts of sesbania gum, 5 parts of compound protein peptide and 1.5 parts of towel gourd concentrated solution; the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 3:5:2; the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 1-3m pieces ² Adding into boiling water, soaking for 15min, filtering, taking out, adding enzyme solution, mixing with fructus Luffae pieces and enzyme solution at a mass/volume ratio g/mL of 3:20, stirring and mixing for 6min, storing for 5 days in dark, suction filtering, pulverizing filter cake, sieving with 400 mesh sieve, adding 90% ethanol solution at a mass/volume ratio g/mL of 10:50, transferring into rotary evaporator, rotary evaporating at 90deg.C for concentrating to 1/5 of original volume, discharging, standing, and cooling to obtain fructus Luffae concentrated solution.

Example 3

The phosphorus-free water-retaining agent for frozen fish slices comprises the following raw materials in parts by weight: 17 parts of trehalose, 0.9 part of chitosan, 0.7 part of L-arginine and 4 parts of sodium citrate4 parts of konjak fine powder, 2 parts of sesbania gum, 3 parts of compound protein peptide and 0.6 part of towel gourd concentrated solution; the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 2:3:1.5; the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 2m pieces ² Adding the fragments into boiling water, soaking for 13min, filtering, taking out, adding enzyme solution, stirring and mixing for 4min, storing for 4 days in dark, filtering, pulverizing filter cake, sieving with 350 mesh sieve, adding 80% ethanol solution, mixing the filter cake powder and the ethanol solution at a mass-volume ratio g/mL of 6:50, rotary evaporating at 80deg.C to concentrate to 1/4 of the original volume, discharging, standing, and cooling to obtain fructus Luffae concentrated solution;

the phosphorus-free water-retaining agent of examples 1-3 was prepared by the following method:

s3, adding sesbania gum and compound protein peptide into the mixture II, slowly adding deionized water, increasing the temperature to 55 ℃, stirring while adding, wherein the stirring speed is 500rpm, and the stirring time is 25min, so as to obtain a viscous liquid;

s4, adding the towel gourd concentrated solution into the viscous liquid, continuously stirring for 3min, performing ultrasonic dispersion for 50min, performing ultrasonic power of 3000W, performing ultrasonic frequency of 60KHz, and performing freeze-drying to obtain the phosphorus-free water-retaining agent.

The specific application method of the phosphorus-free water-retaining agent comprises the following steps:

b) Slicing muscle at back of fish, soaking fish slices with specification of 3cm×3cm×3mm in water-retaining agent for 30min, and slowly stirring every 5 min;

Example 4

The phosphorus-free water-retaining agent for frozen fish slices comprises the following raw materials in parts by weight: 17 parts of trehalose, 0.9 part of chitosan, 0.7 part of L-arginine, 4 parts of sodium citrate, 4 parts of konjak fine powder, 2 parts of sesbania gum, 3 parts of compound protein peptide and 0.6 part of towel gourd concentrated solution; the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 2:3:1.5; the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 2m pieces ² Adding the fragments into boiling water, soaking for 13min, filtering, taking out, adding enzyme solution, stirring and mixing for 4min, storing for 4 days in dark, filtering, pulverizing filter cake, sieving with 350 mesh sieve, adding 80% ethanol solution, mixing the filter cake powder and the ethanol solution at a mass-volume ratio g/mL of 6:50, rotary evaporating at 80deg.C to concentrate to 1/4 of the original volume, discharging, standing, and cooling to obtain fructus Luffae concentrated solution;

the preparation method of the phosphorus-free water-retaining agent comprises the following steps:

s3, adding sesbania gum and compound protein peptide into the mixture II, slowly adding deionized water, increasing the temperature to 40 ℃, stirring while adding, wherein the stirring speed is 400rpm, and the stirring time is 15min, so as to obtain a viscous liquid;

s4, adding the towel gourd concentrated solution into the viscous liquid, continuously stirring for 1min, performing ultrasonic dispersion for 40min, performing ultrasonic power of 2500W, performing ultrasonic frequency of 20KHz, and performing freeze-drying to obtain the phosphorus-free water-retaining agent.

b) Slicing muscle at back of fish, soaking fish slices with specification of 3cm×3cm×3mm in water-retaining agent for 20min, and slowly stirring every 5 min;

Example 5

s3, adding sesbania gum and compound protein peptide into the mixture II, slowly adding deionized water, increasing the temperature to 65 ℃, stirring while adding, wherein the stirring speed is 600rpm, and the stirring time is 30min, so as to obtain a viscous liquid;

s4, adding the towel gourd concentrated solution into the viscous liquid, continuously stirring for 5min, performing ultrasonic dispersion for 60min, performing ultrasonic power of 3500W, performing ultrasonic frequency of 100KHz, and performing freeze-drying to obtain the phosphorus-free water-retaining agent.

b) Slicing muscle at back of fish, soaking fish slices with specification of 3cm×3cm×3mm in water-retaining agent for 40min, and slowly stirring every 5 min;

Comparative example 1

The phosphorus-free water-retaining agent for frozen fish slices comprises the following raw materials in parts by weight: 5 parts of trehalose, 0.2 part of chitosan, 1.5 parts of L-arginine, 8 parts of sodium citrate, 8 parts of konjak fine powder, 1 part of sesbania gum, 10 parts of compound protein peptide and 0.5 part of towel gourd concentrated solution; the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 2:3:1.5; the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 2m pieces ² Adding the fragments into boiling water, soaking for 13min, filtering, taking out, adding enzyme solution, stirring and mixing for 4min, storing for 4 days in dark, filtering, pulverizing filter cake, sieving with 350 mesh sieve, adding 80% ethanol solution, mixing the filter cake powder and the ethanol solution at a mass-volume ratio g/mL of 6:50, rotary evaporating at 80deg.C to concentrate to 1/4 of the original volume, discharging, standing, and cooling to obtain fructus Luffae concentrated solution;

Comparative example 2

The difference between the comparative example and the example 3 is that the phosphorus-free water-retaining agent does not comprise a luffa concentrated solution, specifically a phosphorus-free water-retaining agent for frozen fish fillets, and comprises the following raw materials in parts by weight: 17 parts of trehalose, 0.9 part of chitosan, 0.7 part of L-arginine, 4 parts of sodium citrate, 4 parts of konjak fine powder, 2 parts of sesbania gum and 3 parts of compound protein peptide; the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 2:3:1.5;

s3, adding sesbania gum and compound protein peptide into the mixture II, slowly adding deionized water, raising the temperature to 55 ℃, stirring while adding at 500rpm for 25min to obtain viscous liquid, performing ultrasonic dispersion for 50min, performing ultrasonic power of 3000W and ultrasonic frequency of 60KHz, and performing freeze-drying to obtain the phosphorus-free water-retaining agent.

Comparative example 3

The comparison example is different from the example 3 in that the composite protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 1:1:1, and the composite protein peptide is a phosphorus-free water-retaining agent for frozen fish slices, and comprises the following raw materials in parts by weight: 17 parts of trehalose, 0.9 part of chitosan, 0.7 part of L-arginine, 4 parts of sodium citrate, 4 parts of konjak fine powder, 2 parts of sesbania gum, 3 parts of compound protein peptide and 0.6 part of towel gourd concentrated solution; the compound protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 1:1:1; the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 2m pieces ² Adding the fragments into boiling water, soaking for 13min, filtering, taking out, adding enzyme solution, stirring and mixing for 4min, storing for 4 days in dark, filtering, pulverizing filter cake, sieving with 350 mesh sieve, adding 80% ethanol solution, mixing the filter cake powder and the ethanol solution at a mass-volume ratio g/mL of 6:50, rotary evaporating at 80deg.C to concentrate to 1/4 of the original volume, discharging, standing, and cooling to obtain fructus Luffae concentrated solution;

Comparative example 4

The difference between the comparative example and the example 3 is that the compound protein peptide does not contain sea anemone polypeptide, in particular to a phosphorus-free water-retaining agent for frozen fish slices, which comprises the following raw materials in parts by weight: 17 parts of trehalose, 0.9 part of chitosan, 0.7 part of L-arginine, 4 parts of sodium citrate, 4 parts of konjak fine powder, 2 parts of sesbania gum, 3 parts of compound protein peptide and 0.6 part of towel gourd concentrated solution; the compound protein peptide is soybean oligopeptide and cicada pupa protein peptide with the mass ratio of 2:1.5; the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 2m pieces ² Adding the fragments into boiling water, soaking for 13min, filtering, taking out, adding enzyme solution, stirring and mixing for 4min, storing for 4 days in dark, filtering, pulverizing filter cake, sieving with 350 mesh sieve, adding 80% ethanol solution, mixing the filter cake powder and the ethanol solution at a mass-volume ratio g/mL of 6:50, rotary evaporating at 80deg.C to concentrate to 1/4 of the original volume, discharging, standing, and cooling to obtain fructus Luffae concentrated solution;

1. Water retention index determination

1. Determination of thawing loss Rate

The phosphorus-free water-retaining agents according to the treatment methods and commercial (Shanghai-related polymers) of the above examples 1 to 5 and comparative examples 1 to 4 were divided into 9 groups, examples 1 to 5 were used as experimental groups 1 to 5, and comparative examples 1 to 4 were used as control groups 1 to 4, and the thawing loss rates thereof were calculated according to the following formulas:

m is in ₁ -the quality of the soaked fish slices; m is m ₂ The quality of the surface moisture of the fillets after thawing;

2. measurement of the cooking loss Rate

Putting the thawed fish slices into a steaming bag, steaming in a water bath kettle at 90 ℃ for 5min, and naturally; cooling to room temperature, sucking water on the surface of the fish slices by filter paper, and calculating the cooking loss rate according to the following formula:

wherein m is ₃ -the mass of water absorbed on the surface of the fish slices;

3. product moisture mass fraction determination

The method is carried out by referring to GB/T606-2003 'general method for measuring moisture of chemical reagent Karl Fischer method'.

The measurement results were as follows:

the result shows that the water-retaining agent can well reduce the influence of ice crystal state of cells and microstructure of muscles on the loss of fish slices after being soaked, maintain the microstructure of the fish slices, reduce juice loss, obviously reduce the thawing loss rate of the fish slices, and simultaneously, the water-retaining agent can enable the pH value of the fish slice muscles to be alkaline and deviate from the isoelectric point of the fish slice muscles, thereby inhibiting the increase of steaming loss, and the-OH in the water-retaining agent and the-H in water molecules are combined more tightly, so that the loss of water in the steaming process is reduced; wherein, the hydrophobic part on the luffa concentrated solution can be combined with the hydrophobic group in the shrimp protein, thereby closing the hydrophobic part on the surface of the muscle, and the hydrophilic part replaces the hydrophobic area in the original fish meat, thereby combining more water molecules, greatly improving the water retention effect and reducing the thawing loss rate.

2. Sensory evaluation criteria

The color, smell, taste, tissue state and taste of the cooked tilapia meat paste are subjected to sensory evaluation by referring to 30 personnel subjected to a certain sensory analysis training from the sensory analysis selection, training and management evaluation general guidelines of GB/T16291.1-2012, and specific evaluation criteria are shown in the following table 1:

table 1 evaluation criteria:

the scoring results were as follows:

the water-retaining agent provided by the invention evaluates the thawed and cooked tilapia meat, has white color, luster and no obvious other colors, has unique delicate flavor of the fish meat, no fishy smell, moderate salty taste, strong juice feel, tight tissue structure, firmness, flat section, no air holes, good taste elasticity and moderate softness.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.

Claims

1. A phosphorus-free water-retaining agent for frozen fish slices is characterized in that: the material comprises the following raw materials in parts by weight: 10-25 parts of trehalose, 0.3-1.5 parts of chitosan, 0.3-1.2 parts of L-arginine, 2-6 parts of sodium citrate, 2-6 parts of konjak fine powder, 1-3 parts of sesbania gum, 2-5 parts of compound protein peptide and 0.9-1.5 parts of towel gourd concentrated solution.

2. A phosphorus-free water retaining agent for frozen fish fillets as defined in claim 1, wherein: the material comprises the following raw materials in parts by weight: 17 parts of trehalose, 0.9 part of chitosan, 0.7 part of L-arginine, 4 parts of sodium citrate, 4 parts of konjak fine powder, 2 parts of sesbania gum, 3 parts of compound protein peptide and 0.6 part of towel gourd concentrated solution.

3. A phosphorus-free water retaining agent for frozen fish fillets as defined in claim 1, wherein: the composite protein peptide is soybean oligopeptide, sea anemone polypeptide and cicada pupa protein peptide with the mass ratio of 1-3:2-5:0.3-2.

4. A phosphorus-free water retaining agent for frozen fish fillets as defined in claim 1, wherein: the concentrated solution is prepared by weighing fresh fructus Luffae, manually washing, removing skin, seed and pulp, cleaning, sun drying, and cutting the rest into 1-3m pieces ² Soaking in boiling water for 10-15min, filtering, taking out, adding enzyme solution, mixing with the weight/volume ratio g/mL of the towel gourd fragments and enzyme solution of 1-3:20, stirring and mixing for 2-6min, storing for 3-5 days in dark place, suction filtering, pulverizing filter cake, sieving with 300-400 mesh sieve, adding 70-90% ethanol solution with the weight/volume ratio g/mL of the filter cake powder and ethanol solution of 2-10:50, transferring into rotary evaporator, rotary evaporating and concentrating at 70-90deg.C to 1/3-5 of original volume, discharging, standing, and cooling to obtain the concentrated solution of towel gourd.

5. A phosphorus-free water retaining agent for frozen fish fillets as defined in claim 4, wherein: the enzyme solution is prepared by adding cellulase accounting for 1.0-1.36% of the mass of towel gourd fragments and neutral protease accounting for 1.2-2.25% of the mass of towel gourd fragments into clear water.

6. The method for preparing the phosphorus-free water-retaining agent for frozen fish fillets, as claimed in claim 1, wherein the method comprises the following steps: the method comprises the following steps:

7. The method for preparing the phosphorus-free water-retaining agent for frozen fish slices as set forth in claim 5, which is characterized in that: the stirring speed is 400-600rpm, and the mixing and stirring time of the S3 is 15-30min.

8. The method for preparing the phosphorus-free water-retaining agent for frozen fish slices as set forth in claim 5, which is characterized in that: the ultrasonic power of the S4 is 2500-3500W, and the ultrasonic frequency is 20-100KHz.

9. Use of the non-phosphate water retaining agent according to any one of claims 1 to 8 in frozen seafood products.

10. The application according to claim 9, characterized in that it comprises the steps of: