Composite phosphorus-free anti-freezing water-retaining agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of fish meat anti-freezing water-retaining agents, and relates to a composite phosphorus-free anti-freezing water-retaining agent and a preparation method and application thereof.The composite phosphorus-free anti-freezing water-retaining agent is prepared from, by mass, 0.5-2.5% of sodium bicarbonate, 1-5% of xylooligosaccharide, 1-5% of sodium gluconate and the balance distilled water. The method comprises the following steps: selecting fresh crisp tilapia mossambica, slaughtering the tilapia mossambica, taking out dorsal muscles, wiping off surface moisture, cutting the dorsal muscles into fish blocks, soaking the fish blocks in a prepared anti-freezing water-retaining agent in proportion, fishing out the fish blocks after soaking, draining off moisture, putting the fish blocks into a sample bag, and putting the sample bag into a refrigerator for freezing and thawing circulation. According to the invention, the texture characteristics of the crisp tilapia mossambica in the freezing and thawing process can be maintained, the reduction of the brittleness of the tilapia mossambica can be delayed, and the defects that the traditional phosphate anti-freezing water-retaining agent can endow aquatic products with metal astringent taste and excessive intake of phosphate can affect the absorption of calcium by human bodies are overcome.

Description

Technical Field

[0001] The invention belongs to the technical field of fish antifreeze water-retaining agents, and in particular relates to a composite phosphorus-free antifreeze water-retaining agent and a preparation method and application thereof. Background Art

[0002] Tilapia is native to Africa and is also known as "African crucian carp". It is a tropical fish. It is the main farmed and processed aquatic product in my country. Crisp tilapia is made by feeding ordinary tilapia with broad beans. The hardness, elasticity and chewiness of the fish meat are significantly improved after feeding, forming a "crisp tilapia" with a crisp taste, which is more popular in the market than ordinary tilapia. Limited by the restrictions of breeding areas and breeding seasons, most companies sell frozen fish fillets, but my country's cold chain technology management is still imperfect. Due to temperature fluctuations during the processing, storage, transportation and sales of aquatic products, there will be multiple freezing-thawing processes, resulting in repeated freezing and thawing. The freezing and thawing process will cause the recrystallization of ice crystals in the muscles of frozen aquatic products, resulting in changes in the size and shape of ice crystals. Smaller ice crystals attach to larger ice crystals, promoting their further growth, causing irreversible mechanical damage to muscle fibers, seriously damaging the integrity and microstructure of muscle tissue, and thus reducing the crispness of crisp tilapia.

[0003] At present, the commonly used method to delay the quality deterioration of aquatic products during frozen storage is to add antifreeze water-retaining agents. The prior art discloses a frozen fish paste myofibrillar protein denaturation slowing gel based on celery polysaccharide and its preparation method (CN118787081A). The celery polysaccharide extracted from the celery pure gel powder through specific chemical and physical treatment steps is added to the tilapia fish paste to delay its quality decline, but the preparation of celery polysaccharide is cumbersome and is not conducive to the application of small and medium-sized enterprises. The prior art discloses a squid fish paste water-retaining agent (CN105076917A), which is composed of 3-5% soy protein powder, 0.01-0.03% transglutaminase, 3-5% seaweed oligosaccharide, 0.5-1% sodium caseinate, 1-3% sodium gluconate, 1-1.5% sorbitol, 1-3% sucrose ester, 0.1-0.3% calcium chloride, and the balance is water. It can improve the gel properties and freezing quality of squid meat paste. However, there is a big difference between minced fish and fish meat, and the formula applied to minced fish cannot be directly applied to fish meat, and the meat quality of squid and tilapia is very different. The prior art discloses a phosphorus-containing water-retaining agent (CN117063967A), which is composed of sodium citrate, sodium bicarbonate, soy protein isolate, sodium tripolyphosphate, sodium pyrophosphate and sodium hexametaphosphate. It can effectively enhance the water-retaining capacity of black carp, avoid a large amount of water loss after long-term freezing and thawing, and improve the quality and processing characteristics of black carp, but the water-retaining agent still contains phosphate components, and excessive use is harmful to human health.

[0004] In summary, there is an urgent need for a low-cost, easy-to-prepare, healthy and green antifreeze and water-retaining agent to maintain the texture characteristics of crispy tilapia during the freeze-thaw process. Summary of the invention

[0005] The purpose of the present invention is to provide a composite phosphorus-free antifreeze water-retaining agent and a preparation method and application thereof, which has the function of maintaining the crispness of crispy tilapia during the freezing and thawing process, and solves the problems in the above-mentioned background technology.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is that the present invention provides a composite phosphorus-free antifreeze water-retaining agent and a preparation method and application thereof, which is composed of the following substances in mass fraction:

[0007] Sodium bicarbonate 0.5-2.5%,

[0008] Xylo-oligosaccharide 1-5%,

[0009] Sodium gluconate 1-5%,

[0010] The rest is distilled water.

[0011] Specifically, it is composed of the following substances by mass fraction:

[0012] Sodium bicarbonate 1-2%,

[0013] Xylo-oligosaccharide 1-3%,

[0014] Sodium gluconate 3-5%,

[0015] The rest is distilled water.

[0016] Specifically, it is composed of the following substances by mass fraction:

[0017] Sodium bicarbonate 1.4%,

[0018] Xylo-oligosaccharide 2.8%,

[0019] Sodium gluconate 3.6%,

[0020] The rest is distilled water.

[0021] A method for preparing a composite phosphorus-free antifreeze water-retaining agent comprises the following steps: adding sodium bicarbonate to water while stirring, and then adding xylooligosaccharide and sodium gluconate while stirring.

[0022] A method for applying a composite phosphorus-free antifreeze water-retaining agent comprises the following steps:

[0023] 1) Select fresh crispy tilapia, kill it, remove the internal organs and fish skin, take out the back muscle and wipe off the surface moisture;

[0024] 2) Cut the back muscle into fish pieces and soak them in the prepared antifreeze and water-retaining agent according to the proportion;

[0025] 3) After soaking, remove the sample, drain the water and put it into a sample bag;

[0026] 4) First, place the sample in a -20℃ refrigerator for 24 hours, then thaw at 4℃ for 24 hours, and then refrozen at -20℃ for 24 hours after thawing. This is considered as one freeze-thaw cycle. Repeat the above steps until the fifth freeze-thaw cycle.

[0027] Specifically, the size of the fish pieces is (4-8cm)×(4-8cm)×(2-6cm).

[0028] Specifically, the mass ratio of the fish block to the antifreeze and water-retaining agent is 1:(2-5).

[0029] Specifically, the soaking treatment time is 1-3 hours.

[0030] Compared with the prior art, the advantages and positive effects of the present invention are:

[0031] The invention can maintain the texture characteristics of the crispy tilapia during the freezing and thawing process, delay the reduction of its crispness, and solve the shortcomings that the traditional phosphate antifreeze water-retaining agent will make the aquatic product have a metallic astringent taste, and excessive intake of phosphate will affect the absorption of calcium by the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a bar chart showing the effect of sodium bicarbonate concentration on the hardness of crispy tilapia fillets after five freeze-thaw cycles;

[0033] Figure 2 It is a bar chart showing the effect of xylo-oligosaccharide concentration on the hardness of crispy tilapia fillets after five freeze-thaw cycles;

[0034] Figure 3 It is a bar chart showing the effect of sodium gluconate concentration on the hardness of crispy tilapia fillets after five freeze-thaw cycles;

[0035] Figure 4 It is a bar chart of the hardness values ​​of the crispy tilapia fillets after 5 freeze-thaw cycles in each embodiment and comparative example. DETAILED DESCRIPTION

[0036] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0038] The raw materials used in the following examples and comparative examples are all commercially available.

[0039] Embodiment 1, a composite phosphorus-free antifreeze water-retaining agent, composed of the following substances in mass fractions:

[0040] Sodium bicarbonate 0.5-2.5%, sodium bicarbonate adjusts the pH of the solution to weak alkalinity, causing muscle protein to swell, exposing more hydrophilic groups, enhancing protein water retention, reducing mechanical damage caused by ice crystal formation during freezing and thawing, and maintaining the structural integrity of myofibrils;

[0041] 1-5% xylooligosaccharide. Xylooligosaccharide is a natural prebiotic and hydrophilic polysaccharide that can concentrate water molecules near the protein surface and bind them to form an incompletely frozen area, which reduces the "eutectic point" temperature of the area, prevents the nucleation and growth of ice crystals, and maintains the structural integrity of myofibrils during the freeze-thaw process.

[0042] Sodium gluconate 1-5% is a monosaccharide derivative that contains both polyhydroxyl groups and ionic groups. It can interact with the hydroxyl and carboxyl groups in protein molecules to saturate the protein molecules, thus avoiding the aggregation and denaturation of myofibrillar proteins during the freeze-thaw process and maintaining the structural integrity of myofibrillar proteins during the freeze-thaw process.

[0043] The rest is distilled water, which is used as a solvent to evenly disperse the components to form a homogeneous solution.

[0044] The preparation method of the composite phosphorus-free antifreeze water-retaining agent is as follows: sodium bicarbonate is added to water while stirring, and then oligoxylose and sodium gluconate are added while stirring. Sodium bicarbonate → dissolves in water → adds oligoxylose → adds sodium gluconate → stirs until clear, and is added step by step while stirring continuously to accelerate molecular diffusion and ensure solution uniformity. Preparation is completed within 30 minutes at room temperature.

[0045] Method of using the above-mentioned composite phosphorus-free antifreeze water-retaining agent:

[0046] 1) Select fresh crispy tilapia, kill it, remove the internal organs and fish skin, take out the back muscle and wipe off the surface moisture;

[0047] 2) Cut the back muscle into fish pieces and soak them in the prepared antifreeze water-retaining agent in proportion. The size of the fish pieces is (4-8 cm) × (4-8 cm) × (2-6 cm). The volume of the fish pieces is standardized to ensure a consistent penetration rate. Preferably, the volume of the fish pieces is 6 cm × 6 cm × 4 cm; the mass ratio of the fish pieces to the antifreeze water-retaining agent is 1: (2-5), preferably, the material-liquid ratio is 1: 3, the soaking time is 1-3 hours, and the penetration efficiency and production cycle are balanced. Preferably, the soaking time is 2 hours;

[0048] 3) After soaking, remove the sample, drain the water and put it into a sample bag to remove the residual liquid on the surface;

[0049] 4) First, place the sample in a -20℃ refrigerator for 24 hours, then thaw at 4℃ for 24 hours, and then refrozen at -20℃ for 24 hours after thawing. This is considered as one freeze-thaw cycle. Repeat the above steps until the fifth freeze-thaw cycle.

[0050] Example 2: A composite phosphorus-free antifreeze water-retaining agent as shown in Example 1, when the concentration of xylooligosaccharides is 3% and the concentration of sodium gluconate is 3%, the concentration of sodium bicarbonate is set to 0.5-2.5%, and the effect of the concentration of sodium bicarbonate on the hardness value is studied; secondly, when the concentration of sodium bicarbonate is 1.5% and the concentration of sodium gluconate is 3%, the concentration of xylooligosaccharides is set to 1-5%, and the effect of the concentration of xylooligosaccharides on the hardness value is studied; finally, when the concentration of sodium bicarbonate is 1.5% and the concentration of xylooligosaccharides is 3%, the concentration of sodium gluconate is set to 1-5%, and the effect of the concentration of sodium gluconate on the hardness value is studied. The single-factor experimental design is shown in the following table:

[0051] Table 1 Single factor experimental design

[0052]

[0053] Determination of texture properties (hardness)

[0054] Referring to the DB4420 / T 51-2024 standard, the hardness value after five freeze-thaw cycles was used to represent the crispness. The fish meat was cut into 2cm×2cm×1.5cm in size as the sample for the texture experiment. The compression experiment was carried out in TPA mode, and the P / 36R probe was selected as the tool. After the weight and height correction of the texture analyzer, the experimental parameters were set as follows: the pressing speed, compression speed and return speed were 2mm / s, 10mm / s, and 2mm / s respectively, the probe trigger force was 0.05N, the compression degree was 30%, and each sample was subjected to more than 12 parallel experiments, and a piece of fish meat was replaced for each parallel experiment. Finally, the parallel data were screened and averaged.

[0055] Effect of sodium bicarbonate concentration on the hardness of crispy tilapia fillets after five freeze-thaw cycles Figure 1As shown, different letters indicate significant differences (P < 0.05). With the increase of sodium bicarbonate concentration, the hardness value of crispy tilapia fillets first increased significantly and then decreased significantly (P < 0.05). When the concentration of sodium bicarbonate was 1.5%, the hardness value of crispy tilapia fillets was the largest, reaching 696.77g. The reason for this phenomenon may be that the sodium bicarbonate solution is weakly alkaline, which increases the pH value of the fish meat. This moves the myofibrillar protein away from its isoelectric point, enhances the electrostatic repulsion between the myofibrillar proteins, and increases the distance between the myofibrils. This helps the dissolution of the myofibrillar protein structure, allowing the fish fillets to retain more water during repeated freezing and thawing, thereby minimizing the damage of ice crystals to the tissue structure. However, high concentrations of sodium bicarbonate will excessively increase the pH value of the solution, destroy the structure of the myofibrillar protein, and thus reduce the hardness value.

[0056] Effect of xylo-oligosaccharide concentration on the hardness of crispy tilapia fillets after five freeze-thaw cycles Figure 2 As shown, different letters indicate significant differences (P < 0.05). With the increase of xylooligosaccharide concentration, the hardness value of crispy tilapia fillets first increased significantly and then decreased significantly (P < 0.05). When the xylooligosaccharide concentration was 3%, the hardness value of crispy tilapia fillets was the largest, reaching 666.56g. The reason for this phenomenon is that xylooligosaccharides can replace water molecules by forming large hydrogen bonds with the polar residues of myofibrillar protein, thereby maintaining the structure of myofibrillar protein and preventing it from being damaged during freeze-thaw cycles. In addition, the free hydroxyl groups of xylooligosaccharides can bind water molecules to form an incompletely frozen zone, lower the regional "eutectic point" temperature, reduce the number of ice crystals formed, and thus slow down the freezing-induced denaturation of myofibrillar protein. On the contrary, excessive xylooligosaccharides can lead to an excessively high ratio of antifreeze to protein, resulting in crystallization and instability of antifreeze, reducing its protective effect on myofibrillar protein, thereby reducing the hardness value.

[0057] Effect of sodium gluconate addition on the hardness of crispy tilapia fillets after 5 freeze-thaw cycles Figure 3 As shown, different letters indicate significant differences (P < 0.05). With the increase of sodium gluconate concentration, the hardness value of crispy tilapia fillet first increased significantly and then decreased significantly (P < 0.05). When the concentration of sodium gluconate was 4%, the hardness value of crispy tilapia fillet was the largest, reaching 642.07g. The reason for this phenomenon is that sodium gluconate is a monosaccharide derivative that contains both polyhydroxyl and ionic groups. It can interact with the hydroxyl and carboxyl groups in myofibrillar protein, making it saturated and avoiding the aggregation and denaturation of myofibrillar protein. As a monosaccharide derivative, sodium gluconate and oligoxylose are both sugar antifreeze agents. Too high a concentration will lead to crystallization and instability, reduce the protective effect on myofibrillar protein, and thus reduce the hardness value.

[0058] Combination Figure 1-3 The Box Behnken response surface method was used to design a response surface experiment according to the range in Table 2, and the composition and proportion of the composite phosphorus-free antifreeze water-retaining agent were obtained as follows: sodium bicarbonate 1%-2%, xylo-oligosaccharide 1%-3%, sodium gluconate 3%-5%. The best formula was sodium bicarbonate 1.4%, xylo-oligosaccharide 2.8%, and sodium gluconate 3.6%.

[0059] Table 2 Response surface experimental design

[0060]

[0061] Example 3: According to the composition and proportion of the composite phosphorus-free antifreeze water-retaining agent shown in Example 2, three groups of comparative experiments were conducted:

[0062] Example 1: Sodium bicarbonate 1.4%, xylo-oligosaccharide 2.8%, sodium gluconate 3.6%;

[0063] Example 2: Sodium bicarbonate 1.5%, xylo-oligosaccharide 3%, sodium gluconate 4%;

[0064] Example 3: Sodium bicarbonate 1.5%, xylo-oligosaccharide 4%, sodium gluconate 3%. Example 3 is designed according to the formula shown in Example 2, but the value is not within the formula concentration range.

[0065] Set up three sets of comparison ratios at the same time.

[0066] Comparative Example 1: Soaking in commercial phosphate antifreeze water-retaining agent;

[0067] Comparative Example 2: Distilled water immersion;

[0068] Comparative Example 3: Fish meat without any treatment.

[0069] Depend on Figure 4 It can be seen that within the concentration range of the present invention, the hardness values ​​of Examples 1-2 are better than those of the comparative examples. Comparative Example 1 is fish meat soaked in a commercial phosphate antifreeze water retaining agent, Comparative Example 2 is fish meat soaked in distilled water, and Comparative Example 3 is fish meat without any treatment. It can be seen that the formula shown in Example 2 is better for maintaining the crispness of crispy tilapia during freeze-thaw.

[0070] Example 4: Example 1 and Comparative Example 1 in Example 3 were taken out for comparative experiment, and Comparative Example 3 was used as a control group. The compared indices were all indices after 5 freeze-thaw cycles.

[0071] The experimental steps are as follows: Take the fish sample, cut it into 1.5cm×1.5cm×1.5cm cubes, weigh the mass before thawing and record it as W1. After thawing at 4℃ for 24h, wipe off the surface moisture and weigh the mass and record it as W2. The formula for calculating thawing loss is as follows:

[0072] Thawing loss (%) = (W1-W2) / W1×100

[0073] Take the fish sample and cut it into 1.5cm×1.5cm×1.5cm cubes. Weigh the mass before thawing and record it as W3. After thawing at 4℃ for 24h, wrap the fish with filter paper and put it into a 50ml centrifuge tube. Then centrifuge it at 4℃ and 4000rpm for 15min. Wipe off the surface water and weigh the mass after centrifugation and record it as W4. The formula for calculating centrifugal loss is as follows:

[0074] Centrifugal loss (%) = (W3-W4) / W3×100

[0075] Take the fish sample and cut it into 1.5cm×1.5cm×1.5cm cubes. Weigh the mass before thawing and record it as W5. Steam the fish in a steamer for 10 minutes. After cooling to room temperature, wipe off the surface moisture and weigh the mass and record it as W6. The formula for calculating cooking loss is as follows:

[0076] Cooking loss (%) = (W5-W6) / W5×100

[0077] The experimental data are shown in Table 3:

[0078] Table 3 Comparison of composite non-phosphorus antifreeze water retaining agent and commercial phosphate antifreeze water retaining agent

[0079]

[0080] Different letters indicate significant differences (P<0.05)

[0081] It can be seen from Table 3 that the crispy tilapia fillets soaked in the composite non-phosphorus antifreeze water retainer have higher hardness values ​​and lower centrifugal loss and cooking loss (P < 0.05). However, there is no significant difference in thawing loss compared with the crispy tilapia fillets soaked in the commercial phosphate antifreeze water retainer (P > 0.05). This shows that the composite non-phosphorus antifreeze water retainer developed by the present invention can be used as a qualified substitute for the commercial phosphate antifreeze water retainer, and the product formula does not contain phosphate, which is healthier for the human body.

[0082] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0083] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A composite phosphorus-free antifreeze water-retaining agent, characterized in that: It is composed of the following substances by mass fraction: Sodium bicarbonate 0.5-2.5%, Xylo-oligosaccharide 1-5%, Sodium gluconate 1-5%, The rest is distilled water.

2. A composite phosphorus-free antifreeze water-retaining agent according to claim 1, characterized in that: It is composed of the following substances by mass fraction: Sodium bicarbonate 1-2%, Xylo-oligosaccharide 1-3%, Sodium gluconate 3-5%, The rest is distilled water.

3. A composite phosphorus-free antifreeze water-retaining agent according to claim 2, characterized in that: It is composed of the following substances by mass fraction: Sodium bicarbonate 1.4%, Xylo-oligosaccharide 2.8%, Sodium gluconate 3.6%, The rest is distilled water.

4. A method for preparing a composite phosphorus-free antifreeze water-retaining agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: Take sodium bicarbonate and add it to the water while stirring, then add xylo-oligosaccharides and sodium gluconate while stirring.

5. The application method of a composite phosphorus-free antifreeze water-retaining agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) Select fresh tilapia, kill it, remove the internal organs and skin, take out the back muscle and wipe off the surface moisture; 2) Cut the back muscle into fish pieces and soak them in the prepared antifreeze and water-retaining agent according to the proportion; 3) After soaking, remove the sample, drain the water and put it into a sample bag; 4) Place the sample bag in a -20°C refrigerator for 24 hours and thaw it at 4°C for 24 hours; 5) After thawing, refrozen at -20°C for 24 hours as one freeze-thaw cycle; 6) Repeat step 5) until the fifth freeze-thaw cycle.

6. The application method of a composite phosphorus-free antifreeze water-retaining agent according to claim 5, characterized in that: The size of the fish pieces is (4-8 cm)×(4-8 cm)×(2-6 cm).

7. The application method of the composite phosphorus-free antifreeze water-retaining agent according to claim 5, characterized in that: The ratio is that the mass ratio of the fish block to the antifreeze water retaining agent is 1:(2-5).

8. The application method of the composite phosphorus-free antifreeze water-retaining agent according to claim 5, characterized in that: The soaking time is 1-3 hours.

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