Biological preservative for tilapia mossambica and preservation method thereof

Abstract

The invention provides a biological fresh-keeping agent for tilapia mossambica and a fresh-keeping method of the tilapia mossambica. The fresh-keeping agent comprises an antioxidant, a humectant, probiotics and a biological enzyme in specific parts by weight. The antioxidant is prepared from tea polyphenol, a chenopodium bicolor extract and an allium macrostemon extract according to a specific mass ratio; the Chenopodium aquilinum extract is prepared by the steps of performing ultrasonic extraction on crushed quinoa and absolute ethyl alcohol and the like; the allium macrostemon extract is obtained through the steps of ultra-high pressure extraction, cavitation and the like of sun-dried bulbs. The humectant can be selected from one or more of glycerol, propylene glycol and xanthan gum; the probiotics are lactobacillus, bifidobacterium and lactobacillus acidophilus in a specific mass ratio; the biological enzyme comprises lysozyme, glucose oxidase and lipase according to a specific mass ratio. The fresh-keeping method comprises the following steps: pretreating tilapia mossambica, soaking the tilapia mossambica with a biological fresh-keeping agent, performing ionizing radiation treatment, and finally performing vacuum packaging or modified atmosphere packaging and cold storage or freezing storage. The fresh-keeping agent and the method can effectively prolong the fresh-keeping period of the tilapia mossambica and maintain the quality and the safety of the

Description

Technical Field

[0001] The present invention relates to the technical field of aquatic product preservation, and particularly relates to a biological preservative for tilapia and a preservation method thereof. Background Art

[0002] Tilapia is an important aquaculture variety, which is characterized by delicious meat and rich nutrition, and is deeply loved by consumers. However, tilapia is easily affected by microbial contamination and oxidation during fishing, transportation and storage, resulting in a decline in its quality and a shortening of its shelf life. Therefore, the development of effective tilapia preservation technology is of great significance for improving the quality of tilapia and extending its shelf life.

[0003] At present, the commonly used tilapia preservation technologies mainly include chemical preservation, physical preservation and biological preservation, etc. Chemical preservation is to inhibit the growth and reproduction of microorganisms by adding chemical preservatives, so as to extend the shelf life of tilapia. However, chemical preservatives may pose potential hazards to human health and also affect the taste and quality of tilapia. Physical preservation is to control environmental factors such as temperature, humidity and gas composition to extend the shelf life of tilapia. However, physical preservation methods require specific equipment and conditions, with high costs and limited preservation effects. Biological preservation is to use natural bioactive substances to inhibit the growth and reproduction of microorganisms, so as to extend the shelf life of tilapia; however, the preservation effects of many single biological preservatives on tilapia are relatively limited. For example, when lysozyme is used alone, although it has a certain antibacterial effect, its effect on extending the preservation period of tilapia is not very significant, and its ability to inhibit protein decomposition, fat oxidation, etc. of tilapia is relatively weak.

[0004] The synergy of composite preservatives is unstable: Even when multiple biological preservatives are used in combination, the synergistic effect between them is not always stable. There are differences in the action mechanisms and application conditions of different preservatives, and in practical applications, due to the complexity of their interactions, the preservation effect may be difficult to achieve the expected value, or there may be interference phenomena in some cases. Summary of the Invention

[0005] In view of this, the present invention proposes a biological preservative for tilapia and a preservation method thereof to solve the above problems.

[0006] The technical solution of the present invention is realized as follows: A biological preservative for tilapia: comprising the following raw materials in parts by weight: 25-50 parts of antioxidant, 13-18 parts of humectant, 5-10 parts of probiotic, 4-10 parts of bioenzyme.

[0007] Further, a biological preservative for tilapia: comprising the following raw materials in parts by weight: 40 parts of antioxidant, 15 parts of humectant, 8 parts of probiotic, 8 parts of bioenzyme.

[0008] Furthermore, the antioxidant is tea polyphenols, extracts of Panderia turkestanica Iljin and extracts of Allium macrostemon Bunge with a mass ratio of (1.5 - 3.6):(1.3 - 5.5):(4.5 - 8.6).

[0009] Furthermore, the extracts of Panderia turkestanica Iljin are prepared by selecting fresh, dried and non - mildewed quinoa as raw materials, pulverizing them, mixing the pulverized Panderia turkestanica Iljin with absolute ethanol at a mass - to - volume ratio of g / mL of 3.5 - 10.5:50, placing them in an ultrasonic extractor for extraction, with an ultrasonic temperature of 40 - 60 °C, an ultrasonic power of 200 - 500 W, an ultrasonic time of 30 - 50 min, filtering and concentrating to obtain the extracts of Panderia turkestanica Iljin.

[0010] Furthermore, the extracts of Allium macrostemon Bunge are obtained by drying the underground bulbs of Allium macrostemon Bunge in the sun or by roasting, pulverizing them through 80 - 110 meshes, adding a methanol - aqueous solution with a volume percentage content of 45 - 55%, with a mass - to - volume ratio of the powder and the formaldehyde - aqueous solution of 5 - 8:25, extracting for 40 - 60 min through a high - pressure extractor at a pressure of 100 - 600 MPa and a temperature of 45 - 55 °C to obtain an extract solution, then subjecting the extract solution to cavitation in a cavitation and cell - wall - breaking extractor, with a cavitation pressure of 45 - 65 MPa, a cavitation temperature of 60 - 65 °C, cavitating for 50 - 90 min, filtering, purifying and concentrating and drying the extract solution to obtain the extracts of Allium macrostemon Bunge.

[0011] Furthermore, the humectant is selected from one or more of glycerol, propylene glycol and xanthan gum.

[0012] Furthermore, the probiotics are Lactobacillus, Bifidobacterium and Lactobacillus acidophilus with a mass ratio of (5.6 - 10.5):(3.2 - 5.9):(4.2 - 8.8), and the viable count of bacteria is ≥1×10 10 cfu / g.

[0013] Furthermore, the bio - enzymes include lysozyme, glucose oxidase and lipase with a mass ratio of (15 - 25):(8 - 13):(4 - 12), and the enzyme activities are all greater than 20000 U / mL.

[0014] Furthermore, a preservation method of a bio - preservative for tilapia includes the following steps:

[0015] S1. Pretreat the tilapia, including cleaning, scaling, eviscerating and cutting the tilapia;

[0016] S2. Soak the pretreated tilapia with the bio - preservative according to any one of claims 1 - 8 for 10 - 30 min at a temperature of 5 - 15 °C.

[0017] S3. Subject the soaked tilapia to ionizing radiation treatment for 15 - 25 min.

[0018] S4. Use vacuum packaging or modified atmosphere packaging, and store it at 0 - 4°C refrigerated or - 18°C frozen.

[0019] Furthermore, the dose of the ionizing radiation treatment is 0.5 - 1 kGy.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The biological preservative of the present invention is extremely outstanding in terms of preservation effect. Its antioxidant is composed of tea polyphenols, extract of Panderia turkestanica and extract of Allium macrostemon, which can effectively inhibit the oxidation reaction, reduce fat oxidation and protein degradation, and maintain the color, flavor and nutritional value of the fish. At the same time, lysozyme and glucose oxidase in the biological enzyme cooperate with probiotics to exert an antibacterial effect and inhibit the growth of microorganisms. In addition, the humectant maintains the moisture of the fish, making the tilapia still tender in taste after storage. Secondly, the components of the preservative are safe and environmentally friendly, mainly from natural substances, harmless to the human body and without chemical residues. Its extraction process uses an environmentally friendly method, reducing environmental pollution. Moreover, the preservation method is easy to operate, including steps such as pretreatment, soaking, ionizing radiation treatment, vacuum packaging or modified atmosphere packaging, and refrigerated or frozen storage, which is easy to realize industrial production, and the treatment conditions are mild and will not have an adverse impact on the quality of the fish. Finally, it can also improve the nutritional value of tilapia. Lipase can decompose fat to make it more easily absorbed by the human body, and probiotics can regulate the microbial community and produce beneficial metabolites, enhancing human immunity and improving intestinal health. Specific Embodiments

[0022] To better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0023] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0024] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can all be obtained from commercial channels.

[0025] Example 1

[0026] A biological preservative for tilapia, comprising the following raw materials in parts by weight: 25 parts of antioxidant, 13 parts of humectant, 5 parts of probiotic, and 4 parts of biological enzyme;

[0027] The antioxidant is tea polyphenols, extract of Panderia turkestanica and extract of Allium macrostemon with a mass ratio of 1.5:1.3:4.5;

[0028] The extract of *Panderia turkestanica* is prepared by selecting fresh, dry and mildew-free quinoa as the raw material, pulverizing it, mixing the pulverized *Panderia turkestanica* with absolute ethanol at a mass-to-volume ratio of g / mL of 3.5:50, placing it in an ultrasonic extractor for extraction at an ultrasonic temperature of 40 °C, an ultrasonic power of 200 W, and an ultrasonic time of 30 min, filtering, and concentrating to obtain the extract of *Panderia turkestanica*;

[0029] The extract of *Allium macrostemon* is obtained by drying the underground bulbs of *Allium macrostemon*, pulverizing them through 80 mesh, adding an aqueous methanol solution with a volume percentage content of 45%, with the mass-to-volume ratio of the powder to the aqueous formaldehyde solution being 5:25, extracting for 40 min through a high-pressure extractor at a pressure of 100 MPa and a temperature of 45 °C to obtain the extract, and then subjecting the extract to cavitation in a cavitation cell disruption extractor at a cavitation pressure of 45 MPa and a cavitation temperature of 60 °C for 50 min, filtering, purifying, concentrating and drying the extract to obtain the extract of *Allium macrostemon*;

[0030] The moisturizer is selected from glycerol;

[0031] The probiotics are Lactobacillus, Bifidobacterium and Lactobacillus acidophilus with a mass ratio of 5.6:3.2:4.2, and the viable count of bacteria is ≥1×10 10 cfu / g;

[0032] The bioenzymes include lysozyme, glucose oxidase and lipase with a mass ratio of 15:8:4, and the enzyme activities are all greater than 20000 U / mL.

[0033] Example 2

[0034] A biological preservative for tilapia comprises the following raw materials in parts by weight: 50 parts of antioxidant, 18 parts of moisturizer, 10 parts of probiotics and 10 parts of bioenzymes;

[0035] The antioxidant is tea polyphenols, the extract of *Panderia turkestanica* and the extract of *Allium macrostemon* with a mass ratio of 3.6:5.5:8.6;

[0036] The extract of *Panderia turkestanica* is prepared by selecting fresh, dry and mildew-free quinoa as the raw material, pulverizing it, mixing the pulverized *Panderia turkestanica* with absolute ethanol at a mass-to-volume ratio of g / mL of 10.5:50, placing it in an ultrasonic extractor for extraction at an ultrasonic temperature of 60 °C, an ultrasonic power of 500 W, and an ultrasonic time of 50 min, filtering, and concentrating to obtain the extract of *Panderia turkestanica*;

[0037] The Allium macrostemon Bunge extract is obtained by drying or roasting the underground bulbs of Allium macrostemon Bunge, crushing them through 110 meshes, adding a methanol aqueous solution with a volume percentage of 55%, and extracting for 60 minutes through an ultra-high pressure extractor at a pressure of 600 MPa and a temperature of 55°C to obtain an extract. Then, the extract is subjected to cavitation in a cavitation cell disruption extractor. The cavitation pressure is 65 MPa, the cavitation temperature is 65°C, and the cavitation time is 90 minutes. The extract is filtered, purified, concentrated and dried to obtain the Allium macrostemon Bunge extract;

[0038] The humectant is selected from propylene glycol;

[0039] The probiotic bacteria are Lactobacillus, Bifidobacterium and Lactobacillus acidophilus with a mass ratio of 10.5:5.9:8.8, and the viable count of bacteria is ≥1×10 10 cfu / g;

[0040] The biological enzymes include lysozyme, glucose oxidase and lipase with a mass ratio of 25:13:12, and the enzyme activities are all greater than 20000 U / mL.

[0041] Example 3

[0042] A biological preservative for tilapia comprises the following raw materials in parts by weight: 40 parts of antioxidant, 15 parts of humectant, 8 parts of probiotic bacteria and 8 parts of biological enzymes;

[0043] The antioxidant is tea polyphenols, Panderia turkestanica extract and Allium macrostemon Bunge extract with a mass ratio of 2.5:4:6.2;

[0044] The Panderia turkestanica extract is prepared by selecting fresh, dry and mildew-free quinoa as the raw material and crushing it. The crushed Panderia turkestanica is mixed with absolute ethanol at a mass-to-volume ratio of g / mL of 7.5:50, placed in an ultrasonic extractor for extraction. The ultrasonic temperature is 50°C, the ultrasonic power is 350 W, and the ultrasonic time is 40 minutes. After filtration and concentration, the Panderia turkestanica extract is obtained;

[0045] The Allium macrostemon Bunge extract is obtained by drying or roasting the underground bulbs of Allium macrostemon Bunge, crushing them through 100 meshes, adding a methanol aqueous solution with a volume percentage of 50%, and extracting for 50 minutes through an ultra-high pressure extractor at a pressure of 300 MPa and a temperature of 50°C to obtain an extract. Then, the extract is subjected to cavitation in a cavitation cell disruption extractor. The cavitation pressure is 55 MPa, the cavitation temperature is 63°C, and the cavitation time is 70 minutes. The extract is filtered, purified, concentrated and dried to obtain the Allium macrostemon Bunge extract;

[0046] The humectant is selected from xanthan gum;

[0047] The probiotic bacteria are Lactobacillus, Bifidobacterium and Lactobacillus acidophilus with a mass ratio of 8.5:4:6.8, and the viable count of bacteria is ≥1×10 10 cfu / g;

[0048] The biological enzymes include lysozyme, glucose oxidase and lipase with a mass ratio of 20:10:8, and the enzyme activities are all greater than 20000 U / mL.

[0049] Example 4

[0050] A preservation method of a biological preservative for tilapia includes the following steps:

[0051] S1. Pretreat the tilapia, including cleaning, scaling, eviscerating and cutting the tilapia;

[0052] S2. Immerse the pretreated tilapia with the biological preservative in Example 3 for 20 min at a temperature of 10 °C;

[0053] S3. Perform ionizing radiation treatment on the immersed tilapia for 20 min, and the dose of ionizing radiation treatment is 0.8 kGy;

[0054] S4. Use vacuum packaging or modified atmosphere packaging and store it at 2 °C in refrigeration.

[0055] Example 5

[0056] A preservation method of a biological preservative for tilapia includes the following steps:

[0057] S1. Pretreat the tilapia, including cleaning, scaling, eviscerating and cutting the tilapia;

[0058] S2. Immerse the pretreated tilapia with the biological preservative in Example 2 for 30 min at a temperature of 15 °C;

[0059] S3. Perform ionizing radiation treatment on the immersed tilapia for 25 min, and the dose of ionizing radiation treatment is 1 kGy;

[0060] S4. Use vacuum packaging or modified atmosphere packaging and store it at -18 °C in freezing storage.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 3 is that the raw material of the biological preservative does not contain an antioxidant.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 3 is that the antioxidant of the biological preservative does not contain extract of Panderia turkestanica.

[0065] Comparative Example 3

[0066] The difference between this comparative example and Example 3 is that the antioxidant in the biological preservative does not contain Allium macrostemon Bunge extract.

[0067] Comparative Example 4

[0068] The difference between this comparative example and Example 3 is that the raw material of the biological preservative does not contain biological enzymes.

[0069] Test Example 1

[0070] The biological preservatives prepared in the above Examples 1 - 3 and Comparative Examples 1 - 4 were used for preservation by the following method:

[0071] S1. Pretreat the tilapia, including cleaning, scaling, eviscerating and cutting the tilapia;

[0072] S2. Immerse the pretreated tilapia with the above biological preservative, the immersion time is 20 min, and the temperature is 10 °C;

[0073] S3. Subject the immersed tilapia to ionizing radiation treatment for 20 min, and the dose of ionizing radiation treatment is 0.8 kGy;

[0074] S4. Use vacuum packaging or modified atmosphere packaging, and store it at 2 °C for 15 days, then test its physicochemical indexes and microbial indexes.

[0075] Comparative Example 5

[0076] The difference between this comparative example and Example 4 is that ionizing radiation treatment is not carried out in the preservation method.

[0077] Test results:

[0078]

[0079] The results show that the example group is superior to the comparative example group in terms of TVB - N value, TBA value, moisture content, total colony count and the number of Shewanella spp.

[0080] From the comparison between Example 3 and Comparative Examples 1 - 3, the antioxidant prepared from tea polyphenols, Panderia turkestanica extract and Allium macrostemon Bunge extract of the present invention effectively slows down the oxidation process of fat in tilapia, reduces the generation of free radicals, and can enhance the resistance of tilapia to microbial contamination. By slowing down the oxidation process, the antioxidant helps to maintain the micro - ecological balance of fish meat, reduce the reproduction of harmful microorganisms, and thus further improve the safety and stability of the product.

[0081] Comparing Example 3 with Comparative Example 4, the bio-enzyme of the present invention can enhance the freshness preservation effect and promote the absorption of nutrients. For tilapia, lysozyme can effectively inhibit the growth of Gram-positive bacteria on and inside the fish body, reducing the contamination and spoilage of the fish body by bacteria; glucose oxidase can oxidize glucose into gluconic acid and hydrogen peroxide. Hydrogen peroxide has a bactericidal effect and can inhibit the growth of bacteria and fungi on the surface of tilapia. In addition, the action of glucose oxidase can also reduce the oxygen content around the fish body, creating an environment unfavorable for the growth of microorganisms; lipase can decompose the fat in the fish body, reducing the harmful substances produced by fat oxidation.

[0082] Comparing Example 3 with Comparative Example 5, through ionizing radiation treatment, the microbial count in tilapia can be significantly reduced, prolonging its freshness preservation period; the enzyme activity can be reduced, delaying the spoilage process of tilapia; ionizing radiation treatment can change the cell membrane permeability of tilapia cells, making the substances inside the cells not easily exude, thereby reducing the loss of nutrients and the invasion of microorganisms. At the same time, changing the cell membrane permeability can also affect the metabolic process of tilapia, delaying its spoilage.

[0083] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A biological preservative for tilapia, characterized in that: It comprises the following raw materials in parts by weight: 25 - 50 parts of antioxidant, 13 - 18 parts of humectant, 5 - 10 parts of probiotic, and 4 - 10 parts of bioenzyme.

2. The biological preservative for tilapia according to claim 1, characterized in that: It comprises the following raw materials in parts by weight: 40 parts of antioxidant, 15 parts of humectant, 8 parts of probiotic, and 8 parts of bioenzyme.

3. The biological preservative for tilapia according to claim 1 or 2, characterized in that: The antioxidant is tea polyphenol, quinoa extract, and allium macrostemon extract with a mass ratio of (1.5 - 3.6):(1.3 - 5.5):(4.5 - 8.6).

4. The biological preservative for tilapia according to claim 3, characterized in that: The quinoa extract is prepared by selecting fresh, dry, and non - mildewed quinoa as the raw material, pulverizing it, mixing the pulverized quinoa with absolute ethanol at a mass - to - volume ratio of g / mL of 3.5 - 10.5:50, placing it in an ultrasonic extractor for extraction, with an ultrasonic temperature of 40 - 60 °C, an ultrasonic power of 200 - 500 W, an ultrasonic time of 30 - 50 min, filtering, and concentrating to obtain the quinoa extract.

5. The biological preservative for tilapia according to claim 3, wherein: The allium macrostemon extract is obtained by sun - drying or roasting the underground bulbs of allium macrostemon, pulverizing them through 80 - 110 meshes, adding a methanol aqueous solution with a volume percentage content of 45 - 55%, with a mass - to - volume ratio of the powder and the formaldehyde aqueous solution of 5 - 8:25, extracting through a high - pressure extractor at a pressure of 100 - 600 MPa and a temperature of 45 - 55 °C for 40 - 60 min to obtain an extract solution, then subjecting the extract solution to cavitation in a cavitation cell disruption extractor, with a cavitation pressure of 45 - 65 MPa, a cavitation temperature of 60 - 65 °C, cavitating for 50 - 90 min, filtering, purifying, concentrating, and drying the extract solution to obtain the allium macrostemon extract.

6. The biological preservative for tilapia according to claim 1 or 2, characterized in that: The humectant is selected from one or more of glycerol, propylene glycol, and xanthan gum.

7. The biological preservative for tilapia according to claim 1 or 2, characterized in that: The probiotics are Lactobacillus, Bifidobacterium and Lactobacillus acidophilus with a mass ratio of (5.6 - 10.5):(3.2 - 5.9):(4.2 - 8.8), and the viable count of bacteria is ≥ 1×10 10 cfu / g.

8. A biological preservative for tilapia according to claim 1 or 2, characterized in that: The bioenzyme comprises lysozyme, glucose oxidase, and lipase with a mass ratio of (15 - 25):(8 - 13):(4 - 12), and the enzyme activity is greater than 20000 U / mL.

9. The preservation method of a biological preservative for tilapia according to claim 1, characterized in that: It comprises the following steps: S1. Pretreat the tilapia, including cleaning, scaling, eviscerating, and cutting the tilapia. S2. Soak the pretreated tilapia with the biological preservative described in any one of claims 1 - 8 for 10 - 30 min at a temperature of 5 - 15 °C. S3. Subject the soaked tilapia to ionizing radiation treatment for 15 - 25 min. S4. Use vacuum packaging or modified - atmosphere packaging and store it refrigerated at 0 - 4 °C or frozen at - 18 °C.

10. The preservation method of a biological preservative for tilapia according to claim 9, characterized in that: The dose of the ionizing radiation treatment is 0.5 - 1 kGy.

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