Composition and application thereof in preparation of products for freezing preservation of pelteobagrus fulvidraco
By using emulsion color protectors prepared by konjac glucomannan, egg white, acetic acid solution, corn oil and phytic acid modified starch, the problem of mucus peeling off during frozen preservation of yellow catfish is solved, and the effect of maintaining the color of the fish and skin smoothness is achieved, and the flesh quality and sensory quality are improved.
Patent Information
- Application Number
- CN202510178771.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-18
- Publication Date
- 2025-05-06
AI Technical Summary
The prior art cannot effectively prevent the mucus on the surface of the fish during the frozen preservation process of yellow catfish, resulting in the loss of bright color of the fish body, the skin is no longer smooth, and severe water loss, affecting the flesh and sensory quality.
Using a composition, including konjac glucomannan, egg white, acetic acid solution, corn oil and phytic acid modified starch, a stable emulsion color protector is prepared by corresponding processes, applied to the surface of the yellow catfish to form a dense protective film to prevent mucus from falling off.
Effectively prevent the mucus on the surface of yellow catfish from falling off, maintaining the color and skin smoothness of the fish body, reducing water loss, improving meat quality and sensory quality, and extending shelf life.
Smart Images
Figure CN119924372A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of aquatic product preservation, and in particular to a composition and application thereof in preparing a product for frozen preservation of yellow catfish. Background Art
[0002] Pelteobagrus fulvidraco, also known as long-spined fish, yellow catfish, and yellow bone fish, is an animal of the genus Pelteobagrus in the family Catfish. The body of the yellow catfish is elongated and slightly stout, with the tip of the snout tilted upward to the dorsal fin, the back flattened laterally, the head slightly large and vertically flattened, the back of the head mostly exposed, the snout blunt and rounded from the back, the mouth large, and the eyes medium-sized. The yellow catfish is famous for its unique color. The back of the living yellow catfish is dark brown, gradually light yellow to the abdomen, with a narrow yellow longitudinal band above and below the lateral line, a yellow horizontal band about above the pelvic fin and the anal fin, and a dark longitudinal stripe in the middle of each leaf of the tail fin. Color is one of the key indicators to measure the quality of the yellow catfish. Bright color and close to the natural wild state indicate that the yellow catfish is in good health and has a good growth environment, which is important for the market sales, ecological breeding practice and scientific research of the yellow catfish.
[0003] Yellow catfish has no scales, but a layer of mucus secreted by skin glands is attached to its body surface, which is a protective barrier to prevent pathogen invasion, reduce friction damage, and help regulate osmotic pressure. Nowadays, yellow catfish is mostly transported and stored at low temperatures. Since this method allows the yellow catfish's body mucus to come into direct contact with the air, ice crystals are generated slowly and in large volumes, destroying the protective layer of the body mucus. After thawing from frozen storage, the yellow mucus on its surface often falls off in large areas, causing the yellow catfish to appear dark in color, its skin to no longer be smooth, and to lose water severely. The sensory experience after steaming is quite different from that of the freshly steamed product.
[0004] In the prior art, some color preservatives are usually applied to the surface of fresh live fish, and then a dense protective film is formed on the surface of the fish through rapid freezing to wrap the live fish, so as to achieve the purpose of cold storage safety. However, the traditional color preservatives currently available on the market have weak adhesion and no stretching ability. The frozen film formed during the freezing process is easy to crack and easily damages the fish's epidermis after thawing. Although those skilled in the art have used Litsea cubeba essential oil / chitosan coating to preserve yellow catfish, improve the storage quality of yellow catfish and extend its shelf life (Deng Yaxin, Hu Guangdi, Sun Hanchang, et al. Effect of Litsea cubeba essential oil / chitosan coating preservation on the storage quality of yellow catfish [J]. Food Science and Technology, 2024, 49(03): 125-132. DOI: 10.13684 / j.cnki.spkj.2024.03.012.), the fresh-keeping coating is used after yellow catfish is slaughtered and sliced, which is not suitable for the large market background of cold chain transportation of fresh yellow catfish, and the cost of Litsea cubeba essential oil is high, which is difficult to promote and use on a large scale. Therefore, it is urgent to develop a yellow catfish cold storage color preservative with easy-to-obtain raw materials and easy to use, and to establish a method to prevent the mucus on the surface of yellow catfish from falling off, maintain color and maintain storage quality during cold chain transportation and frozen storage. Summary of the invention
[0005] In order to solve the above problems existing in the prior art, the present invention provides a composition and its application in preparing a product for frozen preservation of yellow catfish.
[0006] The first object of the present invention is to provide a composition.
[0007] The second object of the present invention is to provide the use of the composition in preparing a product for frozen preservation of yellow catfish
[0008] The third object of the present invention is to provide a method for preparing a protective agent for frozen preservation of yellow catfish.
[0009] The fourth object of the present invention is to provide a protective agent obtained by the preparation method.
[0010] The fifth object of the present invention is to provide the use of the protective agent in the frozen preservation of yellow catfish.
[0011] A sixth object of the present invention is to provide a method for freezing and preserving yellow catfish.
[0012] In order to achieve the above object, the present invention is implemented by the following scheme:
[0013] A composition comprises konjac glucomannan, egg white, acetic acid solution, corn oil and phytic acid modified starch; the mass ratio of the konjac glucomannan to the egg white is (0.8-1):(4-5); the mass ratio of the corn oil to the phytic acid modified starch is (8-10):(1-2); and the concentration of the acetic acid solution is 1v / v% to 2v / v%.
[0014] Preferably, the egg white is any one of chicken egg white, duck egg white or goose egg white.
[0015] More preferably, the egg white is duck egg white.
[0016] Preferably, the mass ratio of the konjac glucomannan to the egg white is 1:5.
[0017] Preferably, the concentration of the acetic acid solution is 1 v / v%.
[0018] Preferably, the mass ratio of the corn oil to the phytic acid modified starch is 10:1.
[0019] The use of any of the compositions in the preparation of products for frozen preservation of yellow catfish should also be within the protection scope of the present invention.
[0020] The present invention utilizes konjac glucomannan, egg white, acetic acid solution, corn oil and phytic acid modified starch to prepare a protective agent for frozen preservation of yellow catfish. The viscous aqueous solution of the aqueous phase is composed of a konjac glucomannan-egg white mixture, an acetic acid solution, water and the like, all of which are adhesives that can be used in the food industry and have good stability. Egg white is often a byproduct of egg yolk products, and most of them are often discarded as waste. The above substances are mixed and dissolved in water to form a gel with good adhesiveness. After heating and freeze-drying treatment, the strength, apparent viscosity and film-forming property of the gel are further improved by enhancing the hydrogen bond force, increasing the diffraction peak intensity, removing surface impurities and the like.
[0021] The oil phase uses corn oil, which is rich in nutrients and has a good moisturizing effect on the skin. The viscosity and moisturizing ability of the emulsified corn oil are improved to a certain extent, ensuring that it can better adhere to the surface of the yellow catfish.
[0022] The emulsifier adopts phytic acid modified starch, which has a small amount of emulsifier and significantly improves the solubility, swelling power and viscosity of the starch after modification, so that it can be better attached to the surface of the yellow catfish. Compared with the unmodified starch, the starch is modified with phytic acid and has a phosphate group, which increases the hydrophilicity, solubility and swelling power. In addition, since sodium phytate contains phosphate groups, it cross-links with the hydroxyl groups in the starch molecules between molecules, and the strength of the cross-linking is much greater than that of the hydrogen bond, and a large number of water molecules are needed to destroy the cross-linking bonds. Therefore, the strength of the modified starch particles is increased, the hydrophilicity is enhanced, it is easy to absorb water and swell, and the viscosity is enhanced.
[0023] A method for preparing a protective agent for frozen preservation of yellow catfish, wherein the protective agent is prepared by using a composition, wherein the composition comprises konjac glucomannan, egg white, acetic acid solution, corn oil and phytic acid modified starch; the mass ratio of the konjac glucomannan to the egg white is (0.8-1):(4-5); the mass ratio of the corn oil to the phytic acid modified starch is (8-10):(1-2); the concentration of the acetic acid solution is 1v / v%-2v / v%. The method comprises the following steps: fully mixing the konjac glucomannan and the egg white to obtain a mixed gel; heating the mixed gel to obtain a mixed solution, and then freeze-drying to obtain a konjac glucomannan-egg white mixture; fully mixing the konjac glucomannan-egg white mixture with the acetic acid solution to obtain a viscous aqueous solution; and fully homogenizing the corn oil, the phytic acid modified starch and the viscous aqueous solution to obtain the protective agent.
[0024] Preferably, in the composition, the egg white is any one of chicken egg white, duck egg white or goose egg white.
[0025] More preferably, in the composition, the egg white is duck egg white.
[0026] Preferably, in the composition, the mass ratio of the konjac glucomannan to the egg white is 1:5.
[0027] Preferably, the method of intimately mixing konjac glucomannan and egg white comprises ultrasound.
[0028] More preferably, the ultrasound is synchronized triple-frequency ultrasound.
[0029] Further preferably, the frequency of the synchronous triple-frequency ultrasound is 20 / 28 / 40 kHz.
[0030] Preferably, the mixed solution is obtained by heating the mixed gel in a water bath.
[0031] More preferably, the conditions for water bath heating include: water bath temperature of 40°C to 50°C, and heating time of 20min to 40min.
[0032] Further preferably, the conditions for water bath heating include: water bath temperature is 45° C., and heating time is 30 min.
[0033] Preferably, the mixed solution is then freeze-dried to obtain a konjac glucomannan-egg white mixture.
[0034] More preferably, the mixed solution is then freeze-dried and ground to obtain a konjac glucomannan-egg white mixture.
[0035] Further preferably, the mixed solution is then freeze-dried, ground, and sieved to obtain a konjac glucomannan-egg white mixture.
[0036] More preferably, the sieve used for screening is a 60-mesh sieve.
[0037] Preferably, in the composition, the concentration of the acetic acid solution is 1 v / v%.
[0038] Preferably, the mass volume ratio of the konjac glucomannan-egg white mixture to the acetic acid solution is (60-80) g:1L.
[0039] More preferably, the mass volume ratio of the konjac glucomannan-egg white mixture to the acetic acid solution is 60g:1L.
[0040] Preferably, the konjac glucomannan-egg white mixture is fully mixed with the acetic acid solution at 45° C. to 55° C. to obtain a viscous aqueous solution.
[0041] More preferably, the konjac glucomannan-egg white mixture is fully mixed with the acetic acid solution at 50° C. to obtain a viscous aqueous solution.
[0042] More preferably, the konjac glucomannan-egg white mixture is added to the acetic acid solution at 50° C., while being stirred for a total of 6 h to 18 h to obtain a viscous aqueous solution.
[0043] More preferably, the konjac glucomannan-egg white mixture is added to the acetic acid solution at 50° C., while being stirred for a total of 12 hours to obtain a viscous aqueous solution.
[0044] Preferably, in the composition, the mass ratio of the corn oil to the phytic acid modified starch is 10:1.
[0045] After emulsification, high pressure homogenization and ultrasonic degassing are used to remove gas in the emulsion, so that the final emulsion color protectant is dispersed and uniform, and the solution viscosity, moisturizing ability, and antioxidant ability are uniform. Further preferably, ultrasonic degassing is also performed after stirring to obtain the viscous aqueous solution.
[0046] Preferably, the mass volume ratio of the corn oil, the phytic acid modified starch and the viscous aqueous solution is (80-100) g:(10-20) g:1L.
[0047] More preferably, the mass volume ratio of the corn oil, the phytic acid modified starch and the viscous aqueous solution is 100g:10g:1L.
[0048] Preferably, the method of sufficiently homogenizing the corn oil, the phytic acid-modified starch and the viscous aqueous solution comprises rapid shearing and high-pressure homogenization.
[0049] More preferably, the rapid shearing conditions include: a rotation speed of 13000 rpm to 15000 rpm, and each time of 1 min to 3 min.
[0050] Further preferably, the rapid shearing conditions include: a rotation speed of 13000 rpm and a time of 1 min each time.
[0051] More preferably, the conditions of the high-pressure homogenization include: a pressure of 20 kPa to 30 kPa, and a cycle number of 5 to 8 times.
[0052] Further preferably, the conditions of the high-pressure homogenization include: a pressure of 20 kPa and a number of cycles of 6 times.
[0053] More preferably, after sufficient homogenization, the protective agent is obtained by standing at 0-10°C for 5-6 hours and then degassing by ultrasonication.
[0054] More preferably, after sufficient homogenization, the mixture is allowed to stand at 4° C. for 5 h and then ultrasonically degassed to obtain the protective agent.
[0055] The protective agent obtained by any of the preparation methods should also be within the protection scope of the present invention.
[0056] The application of the protective agent in the frozen storage of yellow catfish should also be within the protection scope of the present invention.
[0057] A method for freezing and preserving yellow catfish comprises freezing and preserving the yellow catfish having a protective agent layer on its body surface, wherein the protective agent layer contains the protective agent.
[0058] Preferably, the method comprises the following steps: wrapping the yellow catfish having a protective agent layer on its body surface with a film, vacuum packaging, and freezing for preservation.
[0059] More preferably, the film is a polyvinyl alcohol / chitosan quaternary ammonium salt film.
[0060] Preferably, the protective agent layer is formed by freezing the protective agent.
[0061] More preferably, the protective agent layer is formed by fully applying the protective agent to the skin surface of the yellow catfish and freezing it at -20°C to -80°C.
[0062] Further preferably, the protective agent layer is formed by fully applying the protective agent to the skin surface of the yellow catfish and freezing it at -80°C.
[0063] Preferably, the cryopreservation temperature is -80°C to 0°C.
[0064] More preferably, the cryopreservation temperature is -40°C to -20°C.
[0065] More preferably, the temperature of the frozen storage is -20°C.
[0066] Preferably, the frozen storage period is 3 to 14 days.
[0067] More preferably, the frozen storage period is 7 days.
[0068] Compared with the prior art, the present invention has the following beneficial effects:
[0069] The invention adopts safe and readily available raw materials and prepares the emulsion color preservative with good stability, good wrapping property and strong adhesion through a relatively simple process. The invention provides effective protection for yellow catfish during frozen storage, prevents the loss of mucus on the surface of the fish body from falling off during thawing, ensures the sensory organ, flavor and meat quality of the fresh yellow catfish, provides a new technical option for the cold chain transportation of yellow catfish, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0070] Figure 1 These are photos of untreated fresh yellow catfish and thawed yellow catfish treated by the methods of Examples 1 to 9.
[0071] Figure 2 These are photos of untreated fresh yellow catfish and thawed yellow catfish treated by the methods of Comparative Examples 1 to 12.
[0072] Figure 3 The color difference statistics of the back of yellow catfish treated with different methods after thawing.
[0073] Figure 4 The color difference statistics of the abdomen of yellow catfish treated with different methods after thawing.
[0074] Figure 5 The statistical results of weight loss rate of Pelteobagrus fulvidraco treated with different methods are shown in the figure.
[0075] Figure 6 The statistical results of water holding capacity of Pelteobagrus fulvidraco treated with different methods are shown in Figure 2. DETAILED DESCRIPTION
[0076] The present invention is further described in detail below in conjunction with the accompanying drawings and specific examples of the specification. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. The test methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified. All additive raw materials involved in the present invention are within the scope of use and dosage described in the Food Additives Use Standard for Frozen Aquatic Products and Their Products (GB 2760, Classification Number: 09.02).
[0077] Example 1 A method for preparing a protective agent and a method for using the protective agent in freezing and preserving yellow catfish
[0078] 1. Preparation method of protective agent
[0079] (1) Preparation of Konjac Glucomannan-Egg White Mixture
[0080] 100 g of konjac glucomannan (CAS No.: 37220-17-0) and 500 g of duck egg white were mixed by synchronous triple-frequency ultrasonic mixing at a frequency of 20 / 28 / 40 kHz for 30 min to obtain a mixed gel; then, the mixed gel was placed in a 45° C. water bath and heated for 30 min to obtain a mixed solution of duck egg white and konjac glucomannan; the mixed solution of duck egg white and konjac glucomannan was freeze-dried, then ground and passed through a 60-mesh sieve to obtain a konjac glucomannan-egg white mixture.
[0081] (2) Preparation of viscous aqueous solution
[0082] Take 10 ml of acetic acid solution and add purified water to prepare 1 v / v% acetic acid solution; add 60 g of konjac glucomannan-egg white mixture to 1 L of 1 v / v% acetic acid solution at 50°C, stirring for a total of 2 hours, ultrasonically degas, cool to 0°C, and prepare a viscous aqueous solution.
[0083] (3) Preparation of emulsion color preservative
[0084] 100 g corn oil and 10 g phytic acid modified starch (CAS No.: 65996-63-6) were added to 1 L of viscous aqueous solution obtained in the previous step, and rapid shearing was performed at a speed of 13000 rpm for 1 min; high pressure homogenization was performed at a pressure of 20 kPa for 6 cycles; after standing at a low temperature of 4° C. for 5 h, ultrasonic degassing was performed to obtain a stable emulsion color preservative, which is the protective agent.
[0085] 2. Method for frozen preservation of yellow catfish using protective agents
[0086] (1) Apply protective agent and quickly freeze to form a film
[0087] Apply the protective agent evenly on the skin surface of fresh yellow catfish in a ratio of 1:1 to the weight of the fish. After ensuring that the protective agent completely covers the surface of the yellow catfish, quickly transfer it to a -80℃ refrigerator and freeze it for 3 hours to form a dense protective ice coat on the surface of the yellow catfish.
[0088] (2) Film packaging, frozen storage
[0089] The yellow catfish with a protective ice coat formed on the surface was wrapped with a polyvinyl alcohol / chitosan quaternary ammonium salt film (Zhai Weikun, Wang Yuansheng, Wang Xuan. Preparation of polyvinyl alcohol / chitosan quaternary ammonium salt film and study on its preservation effect on yellow catfish [J]. Food Industry Science and Technology, 2020, 41(06): 239-243. DOI: 10.13386 / j.issn1002-0306.2020.06.040.), then vacuum-packed and transferred to a -20℃ refrigerator for frozen storage.
[0090] Example 2 A method for preparing a protective agent and a method for using the protective agent in freezing and preserving yellow catfish
[0091] 1. Preparation method of protective agent
[0092] The method is substantially the same as Example 1, except that in step "(1) preparation of konjac glucomannan-egg white mixture", the amount of konjac glucomannan used is 80 g.
[0093] 2. Method for frozen preservation of yellow catfish using protective agents
[0094] Same as Example 1.
[0095] Example 3 A method for preparing a protective agent and a method for using the protective agent in freezing and preserving yellow catfish
[0096] 1. Preparation method of protective agent
[0097] The method is substantially the same as Example 1, except that in step "(1) preparation of konjac glucomannan-egg white mixture", the amount of duck egg white used is 400 g.
[0098] 2. Method for frozen preservation of yellow catfish using protective agents
[0099] Same as Example 1.
[0100] Example 4 Preparation method of a protective agent and method for freezing and preserving yellow catfish
[0101] 1. Preparation method of protective agent
[0102] The method is substantially the same as Example 1, except that in step "(1) preparation of konjac glucomannan-egg white mixture", 500 g of chicken egg white is used instead of 500 g of duck egg white.
[0103] 2. Method for frozen preservation of yellow catfish using protective agents
[0104] Same as Example 1.
[0105] Example 5 A method for preparing a protective agent and a method for using the protective agent in freezing and preserving yellow catfish
[0106] 1. Preparation method of protective agent
[0107] The method is substantially the same as Example 1, except that in step "(1) preparation of konjac glucomannan-egg white mixture", 500 g of goose egg white is used instead of 500 g of duck egg white.
[0108] 2. Method for frozen preservation of yellow catfish using protective agents
[0109] Same as Example 1.
[0110] Example 6 Preparation method of a protective agent and method for freezing and preserving yellow catfish
[0111] 1. Preparation method of protective agent
[0112] The method is basically the same as Example 1, except that in step "(2) preparation of viscous aqueous solution", 20 ml of acetic acid solution is taken and purified water is added to prepare 1 L of 2 v / v% acetic acid solution.
[0113] 2. Method for frozen preservation of yellow catfish using protective agents
[0114] Same as Example 1.
[0115] Example 7 A method for preparing a protective agent and a method for using the protective agent in freezing and preserving yellow catfish
[0116] 1. Preparation method of protective agent
[0117] The method is basically the same as Example 1, except that in step "(2) preparation of viscous aqueous solution", 80 g of konjac glucomannan-egg white mixture is added to 1 L of 1 v / v% acetic acid solution at 50°C.
[0118] 2. Method for frozen preservation of yellow catfish using protective agents
[0119] Same as Example 1.
[0120] Example 8 A method for preparing a protective agent and a method for using the protective agent in freezing and preserving yellow catfish
[0121] 1. Preparation method of protective agent
[0122] The method is basically the same as Example 1, except that in step "(3) preparation of emulsion color preservative", the amount of corn oil used is 80 g, and the amount of phytic acid modified starch used is 20 g.
[0123] 2. Method for frozen preservation of yellow catfish using protective agents
[0124] Same as Example 1.
[0125] Example 9: A method for preparing a protective agent and a method for using the protective agent in freezing and preserving yellow catfish
[0126] 1. Preparation method of protective agent
[0127] The process is basically the same as Example 1, except that in step "(3) preparation of emulsion color preservative", rapid shearing is performed at a rotation speed of 15000 rpm for 3 minutes each time, and high pressure homogenization is performed at a pressure of 30 kPa for 5 cycles.
[0128] 2. Method for frozen preservation of yellow catfish using protective agents
[0129] Same as Example 1.
[0130] Comparative Example 1 A method for freezing and preserving yellow catfish using clean water
[0131] (1) Apply clean water and quickly freeze to form a film
[0132] Apply clean water evenly on the skin surface of fresh yellow catfish, ensure that the clean water covers the surface of the yellow catfish, and then quickly transfer it to a -80℃ refrigerator for 3 hours to form a protective ice coat on the surface of the yellow catfish.
[0133] (2) Film packaging, frozen storage
[0134] The yellow catfish with ice coating formed on the surface is wrapped with polyvinyl alcohol / chitosan quaternary ammonium salt film, then vacuum packed and transferred to a -20℃ refrigerator for frozen storage.
[0135] Comparative Example 2 A method for freezing and preserving yellow catfish using a commercially available protective agent
[0136] (1) Apply commercially available protective agent and quickly freeze to form a film
[0137] Apply commercially available protective agents (main ingredients are chitosan, sodium hexametaphosphate, trehalose, etc.) evenly on the skin surface of fresh yellow catfish, ensure that clean water covers the surface of the yellow catfish, and then quickly transfer it to a -80℃ refrigerator for 3 hours to form a protective ice coat on the surface of the yellow catfish.
[0138] (2) Film packaging, frozen storage
[0139] The yellow catfish with ice coating formed on the surface is wrapped with polyvinyl alcohol / chitosan quaternary ammonium salt film, then vacuum packed and transferred to a -20℃ refrigerator for frozen storage.
[0140] Comparative Example 3: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0141] 1. Preparation method of protective agent
[0142] The method is basically the same as Example 1, except that in step "(3) preparation of emulsion color preservative", the pressure of high-pressure homogenization is 10 kPa and the number of cycles is 2.
[0143] 2. Method for frozen preservation of yellow catfish using protective agents
[0144] Same as Example 1.
[0145] Comparative Example 4: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0146] 1. Preparation method of protective agent
[0147] The method is basically the same as Example 1, except that in step "(3) preparation of emulsion color preservative", the frequency of the synchronous triple-frequency ultrasound is 20 / 28 / 40 kHz.
[0148] 2. Method for frozen preservation of yellow catfish using protective agents
[0149] Same as Example 1.
[0150] Comparative Example 5: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0151] 1. Preparation method of protective agent
[0152] (1) Preparation of duck egg white freeze-dried powder
[0153] Take 500g of duck egg white and subject it to synchronous triple-frequency ultrasonic mixing treatment with a frequency of 20 / 28 / 40kHz for 30min to obtain duck egg white gel; then, place the mixed gel in a 45°C water bath and heat it for 30min to obtain a duck egg white solution; the duck egg white solution is freeze-dried and then ground through a 60-mesh sieve to obtain duck egg white freeze-dried powder.
[0154] (2) Preparation of viscous aqueous solution
[0155] Take 10 ml of acetic acid solution and add purified water to prepare 1 v / v% acetic acid solution; add 60 g of duck egg white freeze-dried powder to 1 L of 1 v / v% acetic acid solution at 50°C, stirring while adding, stir for a total of 2 hours, degas by ultrasonication, cool to 0°C, and prepare a viscous aqueous solution.
[0156] (3) Preparation of emulsion color preservative
[0157] Same as Example 1.
[0158] 2. Method for frozen preservation of yellow catfish using protective agents
[0159] Same as Example 1.
[0160] Comparative Example 6: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0161] 1. Preparation method of protective agent
[0162] (1) Preparation of konjac glucomannan freeze-dried powder
[0163] 100 g of konjac glucomannan was taken and subjected to synchronous triple-frequency ultrasonic mixing treatment at a frequency of 20 / 28 / 40 kHz for 30 minutes to obtain a konjac glucomannan gel; then, the mixed gel was placed in a 45° C. water bath and heated for 30 minutes to obtain a konjac glucomannan solution; the konjac glucomannan solution was freeze-dried and then ground through a 60-mesh sieve to obtain a konjac glucomannan freeze-dried powder.
[0164] (2) Preparation of viscous aqueous solution
[0165] Take 10 ml of acetic acid solution and add purified water to prepare 1 v / v% acetic acid solution; add 60 g of konjac glucomannan freeze-dried powder to 1 L of 1 v / v% acetic acid solution at 50°C, stirring for 2 hours, ultrasonically degas, cool to 0°C, and prepare a viscous aqueous solution.
[0166] (3) Preparation of emulsion color preservative
[0167] Same as Example 1.
[0168] 2. Method for frozen preservation of yellow catfish using protective agents
[0169] Same as Example 1.
[0170] Comparative Example 7: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0171] 1. Preparation method of protective agent
[0172] Same as Example 1.
[0173] 2. Method for frozen preservation of yellow catfish using protective agents
[0174] The method is basically the same as Example 1, except that in step "(1) applying a protective agent and rapidly freezing to form a film", after ensuring that the color protective agent completely covers the surface of the yellow catfish, the fish is rapidly placed in a -20°C refrigerator and frozen for 3 hours to form a dense protective ice coat on the surface of the yellow catfish.
[0175] Comparative Example 8: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0176] 1. Preparation method of protective agent
[0177] Same as Example 1.
[0178] 2. Method for frozen preservation of yellow catfish using protective agents
[0179] The method is basically the same as Example 1, except that in step "(1) applying a protective agent and rapidly freezing to form a film", after ensuring that the color protecting agent completely covers the surface of the yellow catfish, liquid nitrogen is rapidly used for freezing for 3 times to form a dense protective ice coat on the surface of the yellow catfish.
[0180] Comparative Example 9: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0181] 1. Preparation method of protective agent
[0182] (1) Preparation of Konjac Glucomannan-Chitosan Mixture
[0183] 100 g of konjac glucomannan and 500 g of chitosan with a concentration of 1 v / v% are taken, and the two are subjected to synchronous triple-frequency ultrasonic mixing treatment with a frequency of 20 / 28 / 40 kHz for 30 minutes to obtain a mixed gel; then, the mixed gel is placed in a 45°C water bath and heated for 30 minutes to obtain a mixed solution of chitosan and konjac glucomannan; the mixed solution of chitosan and konjac glucomannan is freeze-dried, then ground and passed through a 60-mesh sieve to obtain a konjac glucomannan-chitosan mixture.
[0184] (2) Preparation of viscous aqueous solution
[0185] Take 10 ml of acetic acid solution and add purified water to prepare 1 v / v% acetic acid solution; add 60 g of konjac glucomannan-chitosan mixture to 1 L of 1 v / v% acetic acid solution at 50°C, stirring for a total of 2 hours, ultrasonically degas, cool to 0°C, and prepare a viscous aqueous solution.
[0186] (3) Preparation of emulsion color preservative
[0187] Same as Example 1.
[0188] 2. Method for frozen preservation of yellow catfish using protective agents
[0189] Same as Example 1.
[0190] Comparative Example 10: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0191] 1. Preparation method of protective agent
[0192] (1) Preparation of konjac glucomannan by ethanol elution
[0193] 200 g of commercially available konjac flour and 800 ml of 33% ethanol by volume are taken, eluted at a speed of 200 r / min for 30 min, and then centrifuged at a speed of 5000 r / min for 10 min; after centrifugation, the supernatant is removed, and the precipitate and ethanol are washed in 33% ethanol by volume at 200 r / min for 5 min according to a volume ratio of 1:4, then centrifuged, and eluted twice repeatedly; the precipitate after centrifugation is collected, put into an oven at 50° C. and dried for 6 h, and after drying, ground through a 60-mesh sieve to obtain ethanol-eluted konjac glucomannan.
[0194] (2) Preparation of viscous aqueous solution
[0195] Take 10 ml of acetic acid solution and add purified water to prepare 1 v / v% acetic acid solution; add 60 g of ethanol to 1 L of 1 v / v% acetic acid solution at 50°C to elute konjac glucomannan while stirring for a total of 2 hours, degas by ultrasonication, and cool to 0°C to prepare a viscous aqueous solution.
[0196] (3) Preparation of emulsion color preservative
[0197] Same as Example 1.
[0198] 2. Method for frozen preservation of yellow catfish using protective agents
[0199] Same as Example 1.
[0200] Comparative Example 11: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0201] 1. Preparation method of protective agent
[0202] The method is substantially the same as Example 1, except that in step “(1) preparation of konjac glucomannan-egg white mixture”, 100 g konjac glucomannan and 500 g duck egg white are mixed by synchronous triple-frequency ultrasonic mixing at a frequency of 20 / 28 / 40 kHz for 30 min to obtain a mixed gel, i.e., the konjac glucomannan-egg white mixture.
[0203] 2. Method for frozen preservation of yellow catfish using protective agents
[0204] Same as Example 1.
[0205] Comparative Example 12: A method for preparing a protective agent and a method for using the protective agent in frozen storage of yellow catfish
[0206] 1. Preparation method of protective agent
[0207] The method is substantially the same as Example 1, except that in step “(1) preparation of konjac glucomannan-egg white mixture”, 100 g konjac glucomannan and 500 g duck egg white are mixed by synchronous triple-frequency ultrasonic treatment at a frequency of 20 / 28 / 40 kHz for 30 min to obtain a mixed gel; then, the mixed gel is freeze-dried, ground and sieved through a 60-mesh sieve to obtain a konjac glucomannan-egg white mixture.
[0208] 2. Method for frozen preservation of yellow catfish using protective agents
[0209] Same as Example 1.
[0210] Application Example 1 Evaluation of the effect of frozen storage of yellow catfish
[0211] 1. Frozen storage
[0212] Fresh yellow catfish were treated by the methods of Examples 1 to 9 and Comparative Examples 1 to 12, 2 fish were used for each treatment, and the fish were frozen and stored for 7 days in total.
[0213] 2. Thawing treatment and determination method
[0214] After the frozen storage, the frozen yellow catfish obtained by different treatment methods were thawed at room temperature (about 25°C) for 6 h, and then placed on kitchen paper to drain the surface moisture until no obvious water droplets fell; the whole body of the fish was gently rubbed with dry kitchen paper for 10 s; the back and abdomen of the yellow catfish were photographed and recorded, and the discoloration and bleaching were analyzed. The sensory conditions of the yellow catfish treated by different methods after thawing were further evaluated and scored according to the standards shown in Table 1, and the untreated fresh yellow catfish (i.e., the untreated group) was used as the control.
[0215] Table 1 Sensory evaluation standards for storage test
[0216]
[0217] The color difference value b* of yellow catfish before and after thawing was measured using a colorimeter, where the b* value represents the hue in the yellow-blue direction. The larger the b* value, the higher the yellow degree, and the smaller the b* value, the higher the blue degree. Untreated fresh yellow catfish (i.e., untreated group) was used as the control.
[0218] The weight of yellow catfish before different treatments (M1) and after thawing (M2) were weighed and recorded respectively, and the weight loss rate was calculated according to the following formula: weight loss rate (%) = (M1-M2) / M1×100%.
[0219] From the thawed yellow catfish, a block of fish meat sample was collected and weighed to obtain a mass m1. The block was wrapped with 3 layers of filter paper and placed in a 50 mL centrifuge tube. The sample was centrifuged at 5000 r / min for 15 min. The precipitate sample after centrifugation was collected and weighed to obtain a mass m2. The water holding capacity of the fish meat was calculated according to the following formula: Water holding capacity (%) = m2 / m1×100%.
[0220] 3. Effect evaluation results
[0221] (1) Sensory evaluation
[0222] like Figure 1 As shown, compared with the untreated fresh yellow catfish, the yellow mucus on the abdomen and back surface of the yellow catfish treated by the methods of Examples 1 to 9 remained basically intact. Figure 2 As shown, compared with the untreated fresh yellow catfish, the yellow mucus on the abdomen and back surfaces of the yellow catfish treated by the methods of Comparative Examples 1 to 12 were all destroyed in large areas to varying degrees, which was completely inconsistent with the surface characteristics of the untreated fresh yellow catfish; among them, the yellow mucus on the surface of the yellow catfish treated by the methods of Comparative Examples 1, 2, 4, 5, 6, 7, 9, 11 and 12 had all fallen off, the back showed a dark black color, and the abdomen was white, which was completely inconsistent with the surface characteristics of the fresh yellow catfish; only a small part of the mucus on the back of the yellow catfish treated by the methods of Comparative Examples 3 and 8 was retained, and the abdomen was white; only a small part of the mucus on the back of the yellow catfish treated by the method of Comparative Example 10 was retained, and only a small part of the mucus on the abdomen was retained, which was far different from the surface characteristics of the yellow catfish in the untreated group.
[0223] The sensory evaluation results are shown in Table 2. It can be seen that the total sensory evaluation scores of the yellow catfish treated by the methods of Examples 1 to 9 are all above 75 points, which are close to those of the untreated fresh yellow catfish; while the total sensory evaluation scores of the yellow catfish treated by the methods of Comparative Examples 1 to 12 are all below 55 points, especially the scores of color and viscosity are significantly lower. The total sensory evaluation scores of the yellow catfish treated by the methods of Comparative Examples 1, 2, 5 and 9 are even as low as below 30 points, which is equivalent to yellow catfish placed at room temperature for 1 day, and almost no preservation effect is achieved.
[0224] Table 2 Sensory evaluation scores of yellow catfish treated by different methods after thawing
[0225]
[0226]
[0227] (2) Color difference evaluation results
[0228] like Figure 3As shown, compared with the untreated fresh yellow catfish, the comprehensive change of the b* value of the abdomen and back of the yellow catfish treated by the methods of Examples 1 to 9 is not large; the b* value of the back of the yellow catfish treated in Comparative Examples 1, 2, 4 to 7, 9, 11 and 12 is greatly reduced, because the yellow mucus on the surface is basically completely shed, while a small part of mucus is still retained on the back of Comparative Examples 3, 8 and 10, and the b* value decreases less; there is a small area of yellow mucus on the abdomen of the yellow catfish treated in Comparative Examples 3 and 10, and the decrease is relatively small compared with the b* value of the abdomen of the yellow catfish treated in other comparative examples.
[0229] (3) Statistical results of weight loss rate and water holding capacity
[0230] like Figure 4 As shown, the weight loss rate of the yellow catfish treated by the methods of Examples 1 to 9 after frozen storage after thawing is significantly lower than that of the yellow catfish treated by the methods of Comparative Examples 1 to 12.
[0231] like Figure 5 As shown, the water holding rate of the yellow catfish treated by the methods of Examples 1 to 9 after frozen storage after thawing is significantly higher than that of the yellow catfish treated by the methods of Comparative Examples 1 to 12.
[0232] The above results show that the protective agent provided by the present invention has good overall stability and high viscosity, can effectively protect the integrity of the yellow mucus on the surface of the yellow catfish, and plays an important role in significantly protecting color, reducing weight loss and holding water. In combination with the corresponding freezing preservation method, the freshness and meat quality of the yellow catfish after frozen storage can be guaranteed to be equivalent to that of fresh yellow catfish. Comprehensive evaluation shows that the yellow catfish treated with the protective agent and method of Example 1 is closest to fresh yellow catfish and has the best effect.
[0233] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. For ordinary technicians in this field, other different forms of changes or modifications can be made based on the above descriptions and ideas. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.
Claims
1. A composition, characterized in that Includes konjac glucomannan, egg white, acetic acid solution, corn oil and phytic acid modified starch; The mass ratio of the konjac glucomannan to the egg white is (0.8-1):(4-5); the mass ratio of the corn oil to the phytic acid modified starch is (8-10):(1-2); and the concentration of the acetic acid solution is 1 v / v% to 2 v / v%.
2. Use of the composition according to claim 1 in preparing a product for frozen preservation of yellow catfish.
3. A method for preparing a protective agent for frozen storage of yellow catfish, characterized in that: The protective agent is prepared by using the composition according to claim 1, The following steps are involved: Fully mixing the konjac glucomannan and the egg white to obtain a mixed gel; The mixed gel is heated to obtain a mixed solution, and then the mixed solution is dried to obtain a konjac glucomannan-egg white mixture; the konjac glucomannan-egg white mixture is fully mixed with the acetic acid solution to obtain a viscous aqueous solution; the corn oil, the phytic acid modified starch and the viscous aqueous solution are fully homogenized to obtain.
4. The preparation method according to claim 3, characterized in that: The mass volume ratio of the konjac glucomannan-egg white mixture to the acetic acid solution is (60-80) g:1L.
5. The preparation method according to claim 3, characterized in that: The mass volume ratio of the corn oil, the phytic acid modified starch and the viscous aqueous solution is (80-100) g:(10-20) g:1L.
6. The preparation method according to claim 3, characterized in that: The mixed gel is heated in a water bath to obtain the mixed solution.
7. The protective agent obtained by the preparation method according to any one of claims 3 to 6.
8. Use of the protective agent according to claim 7 in the frozen preservation of Pelteobagrus fulvidraco.
9. A method for freezing and preserving yellow catfish, characterized in that: A frozen preserved yellow catfish having a protective agent layer on its body surface, wherein the protective agent layer comprises the protective agent according to claim 7.
10. The method according to claim 9, characterized in that The protective agent layer is formed by freezing the protective agent.