Preservation method of grouper slices

Abstract

The invention provides a fresh-keeping method of grouper slices. The fresh-keeping method comprises the following steps: S1, preparing a fresh-keeping agent by taking amino glucan, casein phosphopeptides, L-glutamine, a chitosan solution, pentosan, propylene glycol alginate, epsilon-polylysine, an acerola cherry extract and water as raw materials; s2, after the grouper is cleaned, cutting the grouper into fillets with uniform thickness, soaking the fillets with sterile ice water, fishing out the fillets, and draining water; s3, soaking the grouper fillets in a preservative, and air-drying the grouper fillets; and S4, after air drying, wrapping with a preservative film, packaging, and storing at low temperature. According to the preservation method disclosed by the invention, the preservative can form a uniform and stable preservative film which is adhered to the surfaces of the fillets, so that the water loss during the preservation of the fillets can be effectively slowed down, the entry of oxygen can be prevented, the degradation of fillet protein and the breeding of microorganisms can be slowed down, and the texture characteristics of the grouper fillets can be effectively maintained; the shelf life of the grouper fillets is effectively prolonged; meanwhile, the meat quality is also ensured.

Description

Technical Field

[0001] The invention relates to the technical field of fish fillet preservation, and in particular to a grouper fillet preservation method. Background Art

[0002] Grouper is a prized marine fish, renowned for its tender, nutritious meat and widespread popularity among consumers. However, grouper fillets are susceptible to microbial contamination and oxidative deterioration during storage and transportation, leading to a decline in quality and a shortened shelf life. Currently, grouper preservation methods primarily rely on chemical preservatives and low temperatures, but these methods have drawbacks. For example, the common use of sulfite chemical preservatives poses safety risks and can easily cause consumer concern. Conventional refrigeration (0-4°C) only delays spoilage for 3-5 days, making it inadequate for long-distance transportation. Furthermore, vacuum packaging alone has limited effectiveness against specific spoilage bacteria. While relatively safe plant-based preservatives have emerged, these lack activity at low temperatures and exhibit limited antimicrobial efficacy, making them ineffective in extending the fish's shelf life and potentially impacting its quality. Summary of the Invention

[0003] In view of this, the present invention provides a method for preserving grouper fillets. The method of the present invention can extend the shelf life of the grouper fillets while ensuring the quality and taste of the grouper fillets.

[0004] The technical solution of the present invention is achieved as follows:

[0005] A method for preserving grouper fillets comprises the following steps:

[0006] S1. Preparation of a preservative: stirring and mixing a chitosan solution with ε-polylysine and acerola cherry extract to obtain a mixed solution; stirring and mixing aminoglucosan and casein phosphopeptide with water, then adding L-glutamine, pentosan, and propylene glycol alginate, stirring and mixing, and finally adding the mixed solution, stirring and mixing, filtering, and collecting the filtrate to obtain a preservative;

[0007] S2. Pretreatment of grouper fillets: fresh grouper is scaled, viscerally removed, and headed, cleaned, and then cut into fillets of uniform thickness. The fillets are soaked in sterile ice water for 5 to 10 minutes to remove blood and impurities from the surface of the fillets, and then removed and drained to obtain pretreated grouper fillets.

[0008] S3, fresh-keeping treatment: soaking the pretreated grouper fillets in a preservative for 2 to 3 minutes, then taking them out and air-drying them to obtain the treated grouper fillets;

[0009] S4. Packaging and storage: Wrap the processed grouper fillets with plastic wrap, place them in a vacuum packaging bag, evacuate the bag, seal it, and then store it in a low-temperature cold storage.

[0010] Further, the preservative comprises the following raw materials by weight: 15-20 parts of aminodextran, 18-23 parts of casein phosphopeptide, 9-10 parts of L-glutamine, 20-26 parts of chitosan solution, 8-10 parts of pentosan, 7-12 parts of propylene glycol alginate, 4-7 parts of epsilon-polylysine, 10-15 parts of Prunus avium extract, and 200-300 parts of water.

[0011] Further, the preservative comprises the following raw materials by weight: 18 parts of aminodextran, 22 parts of casein phosphopeptide, 10 parts of L-glutamine, 23 parts of chitosan solution, 9 parts of pentosan, 10 parts of propylene glycol alginate, 5 parts of epsilon-polylysine, 13 parts of Prunus avium extract, and 220 parts of water.

[0012] Further, the preparation method of the chitosan solution is as follows: adding chitosan into acetic acid solution under stirring, filtering, and obtaining the chitosan solution.

[0013] Further, the stirring temperature is 30-35 DEG C, the stirring speed is 250-300 r / min, and the time is 60-70 min.

[0014] Further, the chitosan and the acetic acid solution have a material liquid ratio g / mL of 1-2:100, and the acetic acid solution has a volume concentration of 1.5%-2.0%.

[0015] Further, the stirring speed is 200-500 rpm, and the time is 8-15 min.

[0016] Further, the air drying is carried out at a temperature of 0 DEG C-4 DEG C, and the film is formed by air blowing at a speed of 1-3 m / s.

[0017] Further, the temperature of the low-temperature refrigerator is controlled at 0 DEG C-4 DEG C, and the relative humidity is controlled at 85%-90%.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The preservative of the present application can form a uniform and stable preservative film adhered to the surface of the fish fillet by using aminodextran, casein phosphopeptide, L-glutamine, chitosan solution, pentosan, propylene glycol alginate, epsilon-polylysine, and Prunus avium extract as raw materials, can effectively slow down the water loss of the fish fillet during preservation, can prevent oxygen from entering, can slow down the degradation of the protein of the fish fillet and the breeding of microorganisms, can effectively maintain the texture characteristics of the Epinephelus fillet, and can effectively prolong the shelf life of the Epinephelus fillet while ensuring the meat quality.

[0020] The preservative of the present invention, through the combined action of aminoglucosan, casein phosphopeptide, chitosan solution, pentosan, propylene glycol alginate, and acerola cherry extract, can form a coating on grouper fillets. This not only blocks oxygen but also improves the water retention and stability of the fillets, while also reducing protein denaturation in the meat. Furthermore, the preservative, in synergistic action with chitosan, ε-polylysine, and other ingredients, effectively inhibits the reproduction and growth of microorganisms during refrigerated storage, effectively extending the shelf life of the grouper fillets. Furthermore, during the preservation process, the coating is more stably adhered to the outer layer of the fillets through appropriate low-temperature air drying, forming a good protective layer. DETAILED DESCRIPTION

[0021] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0022] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0023] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0024] Example 1

[0025] The chitosan solution was prepared by adding chitosan to an acetic acid solution at a temperature of 30° C. and a stirring speed of 250 r / min, stirring for 70 minutes, and filtering to obtain a chitosan solution; wherein the material-liquid ratio of chitosan to acetic acid solution was 1:100 g / mL; and the volume concentration of the acetic acid solution was 2.0%.

[0026] A method for preserving grouper fillets comprises the following steps:

[0027] S1. Weigh the following preservative raw materials according to weight: 15 parts of aminodextran, 18 parts of casein phosphopeptide, 9 parts of L-glutamine, 20 parts of chitosan solution, 8 parts of pentosan, 7 parts of propylene glycol alginate, 4 parts of ε-polylysine, 10 parts of acerola cherry extract, and 200 parts of water.

[0028] S2. Preparation of a preservative: Chitosan solution, ε-polylysine, and acerola cherry extract were stirred at 200 rpm for 8 minutes to obtain a mixed solution; Glycosaminoglycan, casein phosphopeptide, and water were stirred at 220 rpm for 10 minutes, L-glutamine, pentosan, and propylene glycol alginate were added and stirred at 320 rpm for 12 minutes, and finally the mixed solution was added and stirred at 400 rpm for 15 minutes, filtered, and the filtrate was collected to obtain a preservative;

[0029] S3, pretreatment of grouper fillets: fresh grouper is descaled, de-entrailed, and headed, cleaned, and cut into fillets of uniform thickness, soaked in sterile ice water for 5 minutes to remove blood and impurities on the surface of the fillets, removed, and drained to obtain pretreated grouper fillets;

[0030] S4, fresh-keeping treatment: soaking the pretreated grouper fillet in a preservative for 2 minutes, taking it out and drying it with air at a temperature of 0° C. and a speed of 3 m / s to form a film, thereby obtaining the treated grouper fillet;

[0031] S5. Packaging and storage: Wrap the processed grouper fillets with plastic wrap, place them in vacuum packaging bags, evacuate the bags and seal them, then place them in a low-temperature cold storage with the temperature controlled at 0°C and the relative humidity controlled at 90% for storage.

[0032] Example 2

[0033] The chitosan solution was prepared by adding chitosan to an acetic acid solution at a temperature of 30° C. and a stirring speed of 260 r / min, stirring for 60 minutes, and filtering to obtain a chitosan solution; wherein the material-liquid ratio of chitosan to acetic acid solution was 1:100 g / mL; and the volume concentration of the acetic acid solution was 1.5%.

[0034] A method for preserving grouper fillets comprises the following steps:

[0035] S1. Weigh the following preservative raw materials according to weight: 16 parts of aminodextran, 20 parts of casein phosphopeptide, 9 parts of L-glutamine, 24 parts of chitosan solution, 10 parts of pentosan, 11 parts of propylene glycol alginate, 6 parts of ε-polylysine, 12 parts of acerola cherry extract, and 280 parts of water.

[0036] S2. Preparation of a preservative: Chitosan solution, ε-polylysine, and acerola cherry extract were stirred at 250 rpm for 9 minutes to obtain a mixed solution; Glycosaminoglycan, casein phosphopeptide, and water were stirred at 220 rpm for 9 minutes, L-glutamine, pentosan, and propylene glycol alginate were added and stirred at 320 rpm for 10 minutes, and finally the mixed solution was added and stirred at 400 rpm for 15 minutes, filtered, and the filtrate was collected to obtain a preservative;

[0037] S3, pretreatment of grouper fillets: fresh grouper is scaled, viscerally removed, and headed, cleaned, and then cut into fillets of uniform thickness. The fillets are soaked in sterile ice water for 8 minutes to remove blood and impurities on the surface of the fillets, and then removed and drained to obtain pretreated grouper fillets;

[0038] S4, fresh-keeping treatment: soaking the pretreated grouper fillet in a preservative for 3 minutes, taking it out and drying it with air at a temperature of 3° C. and a speed of 2 m / s to form a film, thereby obtaining the treated grouper fillet;

[0039] S5. Packaging and storage: Wrap the processed grouper fillets with plastic wrap, place them in vacuum packaging bags, evacuate them, seal them, and then store them in a low-temperature cold storage at a controlled temperature of 3° C. and a relative humidity of 90%.

[0040] Example 3

[0041] The chitosan solution was prepared by adding chitosan to an acetic acid solution at a temperature of 35° C. and a stirring speed of 300 r / min, stirring for 70 minutes, and filtering to obtain a chitosan solution; wherein the material-liquid ratio of chitosan to acetic acid solution was 2:100 g / mL; and the volume concentration of the acetic acid solution was 2.0%.

[0042] A method for preserving grouper fillets comprises the following steps:

[0043] S1. Weigh the following preservative raw materials according to weight: 18 parts of aminodextran, 22 parts of casein phosphopeptide, 10 parts of L-glutamine, 23 parts of chitosan solution, 9 parts of pentosan, 10 parts of propylene glycol alginate, 5 parts of ε-polylysine, 13 parts of acerola cherry extract, and 220 parts of water.

[0044] S2. Preparation of a preservative: Chitosan solution, ε-polylysine, and acerola cherry extract were stirred at 300 rpm for 8 minutes to obtain a mixed solution; Glycosaminoglycan, casein phosphopeptide, and water were stirred at 200 rpm for 10 minutes, and then L-glutamine, pentosan, and propylene glycol alginate were added and stirred at 300 rpm for 12 minutes. Finally, the mixed solution was added and stirred at 500 rpm for 12 minutes, and the mixture was filtered to obtain the preservative;

[0045] S3, pretreatment of grouper fillets: fresh grouper is scaled, viscerally removed, and headed, cleaned, and then cut into fillets of uniform thickness. The fillets are soaked in sterile ice water for 60 minutes to remove blood and impurities on the surface of the fillets, and then removed and drained to obtain pretreated grouper fillets;

[0046] S4, fresh-keeping treatment: soaking the pretreated grouper fillets in a preservative for 2 minutes, taking them out and drying them at a temperature of 2° C. with a wind speed of 3 m / s to form a film, thereby obtaining the treated grouper fillets;

[0047] S5. Packaging and storage: Wrap the processed grouper fillets with plastic wrap, place them in vacuum packaging bags, evacuate the bags, seal them, and then place them in a low-temperature cold storage with a temperature of 2° C. and a relative humidity of 85% for storage.

[0048] Comparative Example 1

[0049] The difference between this comparative example and Example 3 is that the raw material ratio of the preservative is changed, and the rest remains the same as Example 3.

[0050] The preservative of this comparative example includes the following raw materials in parts by weight: 10 parts of aminodextrose, 10 parts of casein phosphopeptide, 25 parts of L-glutamine, 18 parts of chitosan solution, 16 parts of pentosan, 5 parts of propylene glycol alginate, 2 parts of ε-polylysine, 24 parts of acerola cherry extract, and 220 parts of water.

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 3 is that the raw materials of the preservative do not contain aminodextran and casein phosphopeptide, and the rest are the same as those in Example 3.

[0053] The preservative of this comparative example comprises the following raw materials in parts by weight: 17 parts of L-glutamine, 30 parts of chitosan solution, 16 parts of pentosan, 17 parts of propylene glycol alginate, 10 parts of ε-polylysine, 20 parts of acerola cherry extract, and 220 parts of water.

[0054] Comparative Example 3

[0055] The difference between this comparative example and Example 3 is that the raw materials of the preservative do not contain pentosan and propylene glycol alginate, and the rest are the same as Example 3.

[0056] The preservative of this comparative example comprises the following raw materials in parts by weight: 21 parts of aminodextran, 25 parts of casein phosphopeptide, 13 parts of L-glutamine, 26 parts of chitosan solution, 10 parts of ε-polylysine, 15 parts of acerola cherry extract, and 220 parts of water.

[0057] Comparative Example 4

[0058] The difference between this comparative example and Example 3 is that: air drying is not performed during the treatment process in step S3, and the product is naturally drained at room temperature. The rest is the same as in Example 3.

[0059] The preservation effects of the preservation methods of Examples 1-3 and Comparative Examples 1-4 were investigated.

[0060] 1. Determination of moisture content

[0061] The determination was carried out in accordance with the direct drying method in the national standard GB 5009.32016 “National Food Safety Standard - Determination of Moisture in Food”, and was carried out on the 1st, 4th, 7th, 10th and 13th day of storage.

[0062] Table 1 Effect of preservation methods on the moisture content of grouper fillets (unit: %)

[0063]

[0064]

[0065] Compared with Comparative Examples 1-4, the preservation methods of Examples 1-3 of the present invention can reduce water volatilization during the fish fillet preservation process. Through the appropriate ratio of preservative ingredients, particularly the synergistic effect of aminoglucosan, casein phosphopeptide, pentosan, and propylene glycol alginate, a protective film can be formed on the surface of the fish fillet, providing excellent water retention, preventing oxygen ingress, and slowing water loss from the fish fillet.

[0066] 2. Determination of total thiol content

[0067] The assay was performed on the 1st, 4th, 7th, 10th and 13th day of storage using the sulfhydryl assay kit, and the absorbance at a wavelength of 412 nm was measured using a microplate reader.

[0068] Table 2 Effects of preservation methods on the total sulfhydryl content of grouper fillets (unit: μmol / g)

[0069] 1 day 4 days 7 days 10 days 13 days Example 1 58.46 57.27 55.83 54.1 50.72 Example 2 55.37 54.24 52.79 51.16 48.04 Example 3 56.72 55.90 54.63 52.29 49.47 Comparative Example 1 56.84 55.63 54.07 52.16 47.82 Comparative Example 2 57.91 55.85 53.41 50.39 44.27 Comparative Example 3 56.25 54.87 52.56 50.42 45.65 Comparative Example 4 55.46 54.21 52.49 50.38 44.52

[0070] The above results indicate that the total thiol content of each preservation method showed a decreasing trend with extended storage time, but the preservation methods of Examples 1-3 of the present invention showed a slower decreasing trend than the preservation methods of Comparative Examples 1-4. This demonstrates that the present invention, through the combination of appropriate preservatives and a suitable air-drying method, can achieve a synergistic effect, effectively mitigating the oxidative denaturation of thiols, and exhibiting a good antibacterial effect. This inhibits the growth of microorganisms in fish fillets, reduces the activity of endogenous enzymes in the fish meat, and effectively delays the degree of protein denaturation in the fish fillets, thereby effectively extending the shelf life of the fish fillets and ensuring their meat quality.

[0071] 3. Determination of texture characteristics

[0072] The hardness and chewiness of fish meat at 10 and 13 days were measured using a TA.XT Plus texture analyzer. The results are as follows:

[0073] Probe speed: pre-test speed 1.0mm / s, test speed 1.0mm / s, post-test speed 5.0mm / s;

[0074] Compression degree: 50% (i.e. the first compression to 50% of the original height of the sample);

[0075] Interval time between two compressions: 5.0 s;

[0076] Trigger force: 5.0 g.

[0077] The grouper fillets of the groups of Examples 1-4 and Comparative Examples 1-4 were taken as test samples, cut into blocks of 2 cm x 2 cm x 1 cm (length x width x thickness), and bone or connective tissue was avoided; the samples were equilibrated at 4°C for 30 min before determination to ensure uniform temperature.

[0078] Table 3 Influence of preservation methods on the texture properties of grouper fillets

[0079]

[0080] The above results show that the texture parameters of the grouper fillets of Examples 1-3 of the present application are significantly better than those of the groups of Comparative Examples 1-4 by reasonable preservation methods, which can effectively delay the texture deterioration of the fillets and ensure the quality of the fillets during preservation.

[0081] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preserving grouper fillets, characterized in that: The following steps are involved: S1. Preparation of a preservative: stirring and mixing a chitosan solution with ε-polylysine and acerola cherry extract to obtain a mixed solution; stirring and mixing aminoglucosan and casein phosphopeptide with water, then adding L-glutamine, pentosan, and propylene glycol alginate, stirring and mixing, and finally adding the mixed solution, stirring and mixing, filtering, and collecting the filtrate to obtain a preservative; S2. Pretreatment of grouper fillets: fresh grouper is scaled, viscerally removed, and headed, cleaned, and then cut into fillets of uniform thickness. The fillets are soaked in sterile ice water for 5 to 10 minutes to remove blood and impurities from the surface of the fillets, and then removed and drained to obtain pretreated grouper fillets. S3, fresh-keeping treatment: soaking the pretreated grouper fillets in a preservative for 2 to 3 minutes, then taking them out and air-drying them to obtain the treated grouper fillets; S4. Packaging and storage: Wrap the processed grouper fillets with plastic wrap, place them in a vacuum packaging bag, evacuate the bag, seal it, and then store it in a low-temperature cold storage.

2. The method for preserving grouper fillets according to claim 1, wherein: The preservative comprises the following raw materials in parts by weight: 15-20 parts of aminodextran, 18-23 parts of casein phosphopeptide, 9-10 parts of L-glutamine, 20-26 parts of chitosan solution, 8-10 parts of pentosan, 7-12 parts of propylene glycol alginate, 4-7 parts of epsilon-polylysine, 10-15 parts of acerola cherry extract, and 200-300 parts of water.

3. The method for preserving grouper fillets according to claim 2, wherein: The preservative comprises the following raw materials in parts by weight: 18 parts of aminodextran, 22 parts of casein phosphopeptide, 10 parts of L-glutamine, 23 parts of chitosan solution, 9 parts of pentosan, 10 parts of propylene glycol alginate, 5 parts of ε-polylysine, 13 parts of acerola cherry extract, and 220 parts of water.

4. The method for preserving grouper fillets according to claim 1, wherein: The chitosan solution is prepared by adding chitosan to an acetic acid solution under stirring, and filtering the solution to obtain the chitosan solution.

5. The method for preserving grouper fillets according to claim 4, characterized in that: The stirring temperature is 30-35° C., the stirring speed is 250-300 r / min, and the stirring time is 60-70 min.

6. The method for preserving grouper fillets according to claim 4, characterized in that: The material-liquid ratio of the chitosan to the acetic acid solution is 1 to 2:100 in g / mL; and the volume concentration of the acetic acid solution is 1.5% to 2.0%.

7. The method for preserving grouper fillets according to claim 1, characterized in that: The stirring and mixing is performed at a rotation speed of 200 to 500 rpm and for a time of 8 to 15 minutes.

8. The method for preserving grouper fillets according to claim 1, characterized in that: The air drying is to form a film by blowing air at a speed of 1 to 3 m / s at a temperature of 0 to 4°C.

9. The method for preserving grouper fillets according to claim 1, characterized in that: The temperature of the low-temperature cold storage is controlled at 0° C. to 4° C., and the relative humidity is controlled at 85% to 90%.

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