Method for directionally inhibiting blackening of euphausia superba and application of chitobiose

Abstract

The invention provides a method for directionally inhibiting blackening of euphausia superba and application of chitobiose, and belongs to the technical field of aquatic product processing. The method comprises the steps of quick freezing and unfreezing; the quick-freezing step is as follows: after the antarctic krill goes ashore, a trehalose and bamboo leaf crude extract mixture is immediately and quickly scattered according to the mass ratio of (800: 1)-(1200: 1), the mass ratio of the trehalose to the bamboo leaf crude extract in the mixture is (1: 6)-(1: 10), and after uniform stirring, the mixture is placed in a plate for quick-freezing under the NH3 refrigeration condition; the unfreezing comprises the following steps: adding chitobiose with the molecular weight of 340D into water according to the ratio of (100: 1)-(300: 1), uniformly stirring, and pre-cooling at the temperature of 0-4 DEG C for later use; the euphausia superba blocks are put into the unfreezing liquid according to the mass ratio of 1: 3-1: 6. The euphausia superba is quickly frozen and unfrozen according to the method disclosed by the invention, so that blackening cannot occur.

Description

Technical Field

[0001] The invention belongs to the technical field of aquatic product processing, and particularly relates to a method for directionally inhibiting the melanization of Antarctic krill and the application of chitobiose. Background Art

[0002] Antarctic krill (Euphausia superba) is the largest single biological resource on Earth, with an estimated biomass of 650 million to 1 billion tons, and is one of the most promising marine biological resources in the world. Antarctic krill is only 4 to 6 cm long, but has high nutritional value, with a protein content of 11.9% to 15.4% of fresh weight. It is considered to be the largest potential animal protein resource on Earth, and contains rich umami amino acids, flavor nucleotides, etc.; the total lipid content accounts for 12 to 50% of the dry weight, and the polyunsaturated fatty acid content is rich, which is easily oxidized.

[0003] However, a notable feature of Antarctic krill is that it contains a powerful enzyme system that can degrade various proteins. After death, Antarctic krill will autolyze or turn black due to the reduced activity of the enzyme inhibition system in the body. During the freezing or thawing process, Antarctic krill is easily affected by factors such as ice crystals and endogenous enzymes, which lead to oxidation reactions of fats and proteins, thus causing quality degradation. Summary of the invention

[0004] The invention provides a method for directionally inhibiting the melanization of Antarctic krill. The method comprises adding green bamboo leaf extract and trehalose during quick freezing. The green bamboo leaf extract contains natural active substances such as arbutin and orientin, which can inhibit enzymes in Antarctic krill and reduce the melanization caused by enzyme system reaction. Trehalose can reduce the formation of ice crystals in Antarctic krill during quick freezing and reduce the denaturation of muscle protein caused by ice crystals during thawing. At the same time, during thawing, a thawing solution containing 300D chitobiose is prepared to further inhibit the activity of enzymes and prevent the melanization of Antarctic krill.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for directional inhibition of Antarctic krill melanization, the method comprising the steps of quick freezing and thawing; the quick freezing step comprises immediately sprinkling a mixture of trehalose and bamboo leaf crude extract at a mass ratio of 800:1 to 1200:1 after the Antarctic krill lands, wherein the mass ratio of trehalose to bamboo leaf crude extract in the mixture is 1:6 to 1:10, stirring evenly and then placing on a plate and quick freezing under NH3 refrigeration conditions;

[0007] The thawing process comprises adding chitobiose with a molecular weight of 340D into water at a ratio of 100:1 to 300:1, stirring evenly, and precooling at 0 to 4°C for standby use; and adding Antarctic krill chunks into the thawing solution at a mass ratio of 1:3 to 1:6.

[0008] As a preferred embodiment, the thawing liquid is replaced every time 5 to 10 batches of Antarctic krill chunks are processed.

[0009] As a preferred embodiment, the preparation method of the bamboo leaf extract is as follows: take a certain weight of green bamboo leaves, add ethanol at a mass-to-volume ratio of 1:5, wherein the volume fraction of ethanol is 60-90%, soak for 3 hours, and then perform ultrasonic-assisted extraction for 1 hour; the extract is filtered to separate the material and liquid to obtain a green bamboo leaf crude extract; the crude extract is further concentrated after passing through D101 macroporous resin, and the concentrated solution is freeze-dried to obtain the green bamboo leaf extract.

[0010] The present invention also provides the use of chitobiose in the preservation of Antarctic krill, and the method comprises the steps of quick freezing and thawing; the quick freezing step comprises immediately sprinkling a mixture of trehalose and bamboo leaf crude extract at a mass ratio of 800:1 to 1200:1 after the Antarctic krill comes ashore, wherein the mass ratio of trehalose to bamboo leaf crude extract in the mixture is 1:6 to 1:10, stirring evenly and then placing on a plate and quick freezing under NH3 refrigeration conditions;

[0011] The thawing process comprises adding chitobiose with a molecular weight of 340D into water at a ratio of 100:1 to 300:1, stirring evenly, and precooling at 0 to 4°C for standby use; and adding Antarctic krill chunks into the thawing solution at a mass ratio of 1:3 to 1:6.

[0012] The beneficial effect of the present invention compared with the prior art is that the Antarctic krill will not turn black when being quickly frozen and thawed according to the method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The blackening of Antarctic krill after different quick freezing and thawing methods. a.1 is the first day of the tap water treatment group, a.2 is the second day of the tap water treatment group, and a.3 is the third day of the tap water treatment group; b.1 is the first day of the 4-HR treatment group, b.2 is the second day of the 4-HR treatment group, and b.3 is the third day of the 4-HR treatment group; c.1 is the first day of the sodium pyrosulfite treatment group, c.2 is the second day of the sodium pyrosulfite treatment group, and c.3 is the third day of the sodium pyrosulfite treatment group; d.1 is the first day of the Nisin treatment group, d.2 is the second day of the Nisin treatment group, and c.3 is the third day of the Nisin treatment group. is the second day of the Nisin treatment group, and d.3 is the third day of the Nisin treatment group; e.1 is the first day of the chitobiose treatment group, e.2 is the second day of the chitobiose treatment group, and e.3 is the third day of the chitobiose treatment group; f.1 is the first day of the chitotriose treatment group, f.2 is the second day of the chitotriose treatment group, and f.3 is the third day of the chitotriose treatment group; g.1 is the first day of the chitotetraose treatment group, g.1 is the second day of the chitotetraose treatment group, and g.3 is the third day of the chitotetraose treatment group. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is further processed below through embodiments, but the protection scope of the present invention is not limited in any form by the embodiments.

[0015] The preparation method of the bamboo leaf extract used in the following embodiments is as follows: take a certain weight of green bamboo leaves, add ethanol at a mass volume ratio of 1:5, wherein the volume fraction of ethanol is 70%, or any percentage between 60-90%, soak for 3 hours, and then perform ultrasonic-assisted extraction for 1 hour; the extract is filtered to separate the material and the liquid to obtain a green bamboo leaf crude extract; the crude extract is further concentrated after passing through a D101 macroporous resin, and the concentrate is freeze-dried to obtain a green bamboo leaf extract.

[0016] The preparation method of chitobiose with a molecular weight of 340D refers to a published patent, the patent name is a chitosanase and its gene and application, and the announcement number is CN107326034B.

[0017] Trehalose: Japanese trehalose was purchased from Nagase (China) Co., Ltd.

[0018] Example 1

[0019] In February 2024, team members completed this experiment on the "Fuxing" ocean-going fishing vessel.

[0020] 1. Processing

[0021] The Antarctic krill in the treatment group were immediately sprinkled with trehalose and bamboo leaf extract (trehalose: bamboo leaf extract = 1:8) at a mass ratio of 900:1 after being pumped ashore, and then placed on a plate and quickly frozen under NH3 refrigeration. The Antarctic krill in the control group, 4-HR group, and sodium metabisulfite group were placed on a plate and quickly frozen under NH3 refrigeration after being caught.

[0022] 2. Preparation of thawing solution

[0023] Take 4 equal volumes of tap water, add tap water, 4-HR, sodium metabisulfite, Nisin, chitobiose, chitotriose and chitotetraose in the ratio of 200:1 (water: compound to prevent blackening) to set up an experimental group, stir evenly, and precool at 0-4℃ for use.

[0024] 3. Thawing

[0025] Add Antarctic krill chunks into the thawing solution at a ratio of 1:4, and observe the blackening of individual Antarctic krill after the chunks are completely thawed.

[0026] 4. The results are as follows Figure 1 As shown, the experimental results show that the treatment group (chitobiose) has the best preservation effect on Antarctic krill.

[0027] Example 2

[0028] In February 2024, team members completed this experiment on the "Fuxing" ocean-going fishing vessel.

[0029] 1. Processing

[0030] The Antarctic krill in the treatment group were immediately sprinkled with trehalose and bamboo leaf crude extract (trehalose: bamboo leaf crude extract = 1:8) at a mass ratio of 800:1 after being pumped ashore, and then placed on a plate and quickly frozen under NH3 refrigeration conditions after being stirred evenly. The Antarctic krill in the control group, 4-HR group, and sodium metabisulfite group were directly placed on a plate and quickly frozen under NH3 refrigeration conditions after being caught.

[0031] 2. Preparation of thawing solution

[0032] Add an equal amount of chitobiose in a ratio of 200:1 (water: compound for preventing blackening), stir evenly, and precool at 0-4°C for later use.

[0033] 3. Thawing

[0034] Add Antarctic krill chunks into the thawing solution at a ratio of 1:4, and observe the blackening of individual Antarctic krill after the chunks are completely thawed.

[0035] 4. The experimental results show that Antarctic krill does not turn black within 1-3 days after thawing.

[0036] Example 3

[0037] In February 2024, team members completed this experiment on the "Fuxing" ocean-going fishing vessel.

[0038] 1. Processing

[0039] The Antarctic krill in the treatment group were immediately sprinkled with trehalose and bamboo leaf crude extract (trehalose: bamboo leaf crude extract = 1:8) at a mass ratio of 1200:1 after being pumped ashore, and then placed on a plate and quickly frozen under NH3 refrigeration conditions after being stirred evenly. The Antarctic krill in the control group, 4-HR group, and sodium metabisulfite group were placed on a plate and quickly frozen under NH3 refrigeration conditions after being caught.

[0040] 2. Preparation of thawing solution

[0041] Add an equal amount of chitobiose in a ratio of 200:1 (water: compound for preventing blackening), stir evenly, and precool at 0-4°C for later use.

[0042] 3. Thawing

[0043] Add Antarctic krill chunks into the thawing solution at a ratio of 1:4, and observe the blackening of individual Antarctic krill after the chunks are completely thawed.

[0044] 5. The experimental results show that Antarctic krill does not turn black within 1-3 days after thawing.

Claims

1. A method for directional inhibition of Antarctic krill melanization, characterized in that: The method comprises the steps of quick freezing and thawing; the quick freezing step comprises immediately sprinkling a mixture of trehalose and bamboo leaf crude extract at a mass ratio of 800:1 to 1200:1 after the Antarctic krill is landed, wherein the mass ratio of trehalose to bamboo leaf crude extract in the mixture is 1:6 to 1:10, stirring evenly and then placing on a plate and quick freezing under NH3 refrigeration conditions; The thawing process comprises adding chitobiose with a molecular weight of 340D into water at a ratio of 100:1 to 300:1, stirring evenly, and precooling at 0 to 4°C for standby use; and adding Antarctic krill chunks into the thawing solution at a mass ratio of 1:3 to 1:

6.

2. The method for directional inhibition of melanization of Antarctic krill according to claim 1, characterized in that: The thawing solution was replaced every time 5 to 10 batches of Antarctic krill blocks were processed.

3. The method for directional inhibition of melanization of Antarctic krill according to claim 1, characterized in that: The preparation method of the bamboo leaf crude extract comprises the following steps: taking a certain weight of green bamboo leaves, adding ethanol at a mass-to-volume ratio of 1:5, wherein the volume fraction of ethanol is 60-90%, soaking for 3 hours, and then ultrasonic-assisted extraction for 1 hour; filtering the extract to separate the material and liquid to obtain a green bamboo leaf crude extract; passing the crude extract through a D101 macroporous resin to further concentrate the crude extract, and freeze-drying the concentrate to obtain the bamboo leaf crude extract.

4. The application of chitobiose in the preservation of Antarctic krill is characterized by: The method comprises the steps of quick freezing and thawing; the quick freezing step comprises immediately sprinkling a mixture of trehalose and bamboo leaf crude extract at a mass ratio of 800:1 to 1200:1 after the Antarctic krill is landed, wherein the mass ratio of trehalose to bamboo leaf crude extract in the mixture is 1:6 to 1:10, stirring evenly and then placing on a plate and quick freezing under NH3 refrigeration conditions; The thawing process comprises adding chitobiose with a molecular weight of 340D into water at a ratio of 100:1 to 300:1, stirring evenly, and precooling at 0 to 4°C for standby use; and adding Antarctic krill chunks into the thawing solution at a mass ratio of 1:3 to 1:

6.

5. The use of chitobiose in the preservation of Antarctic krill according to claim 4, characterized in that: The preparation method of the bamboo leaf crude extract comprises the following steps: taking a certain weight of green bamboo leaves, adding ethanol at a mass-to-volume ratio of 1:5, wherein the volume fraction of ethanol is 60-90%, soaking for 3 hours, and then ultrasonic-assisted extraction for 1 hour; filtering the extract to separate the material and liquid to obtain a green bamboo leaf crude extract; passing the crude extract through a D101 macroporous resin and further concentrating the crude extract, and freeze-drying the concentrate to obtain a green bamboo leaf extract.

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