Sea cucumber fresh-keeping liquid as well as preparation method and application thereof

Abstract

The invention belongs to the field of food processing, and particularly relates to sea cucumber fresh-keeping liquid as well as a preparation method and application thereof. The fresh-keeping liquid is prepared from a grape seed extract, a spearmint extract and epsilon-polylysine hydrochloride. The compound fresh-keeping liquid is adopted, so that the taste of the instant sea cucumber is improved, the phenomenon of quality deterioration of the instant sea cucumber is improved, and the storage stability of the instant sea cucumber is enhanced.

Description

Technical Field

[0001] The invention belongs to the field of food processing, and in particular relates to a sea cucumber preservative liquid and a preparation method and application thereof. Background Art

[0002] Sea cucumbers are rich in a variety of active substances and are a high-value marine food that can be used as both medicine and food. Their products are becoming more and more popular in the market. Due to the autolysis phenomenon of sea cucumbers, the sea cucumber tissue will become soft and melt, so the sea cucumbers need to be heated as soon as possible after being caught. Ready-to-eat sea cucumbers are one of the main product forms of sea cucumbers. They are widely favored by consumers because of their simple and easy to eat and good taste. Ready-to-eat sea cucumbers are generally made by boiling, seasoning or not seasoning, packaging, high temperature and high pressure sterilization and other steps of fresh sea cucumbers. However, after the sea cucumbers are treated with high temperature and high pressure, the protein structure of the ready-to-eat sea cucumbers is destroyed, which affects the texture of the ready-to-eat sea cucumbers, which is manifested as the sea cucumbers becoming softer and less elastic.

[0003] Some companies use non-high-pressure technology to ensure the shape and taste of sea cucumbers. However, during refrigerated storage, as the storage time increases, microorganisms will use sea cucumber protein to grow and reproduce, causing the quality of sea cucumbers to deteriorate. At the same time, the oxidation degradation of ready-to-eat sea cucumber protein itself will cause the triple helix structure to change, causing changes in the functional properties of the protein and loosening of the sea cucumber tissue, which will shorten the storage time of ready-to-eat sea cucumbers. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a sea cucumber preservative liquid, comprising grape seed extract, spearmint extract and ε-polylysine hydrochloride.

[0005] Furthermore, the content of the grape seed extract is 0.01wt% to 1.0wt%, the content of the spearmint extract is 0.01wt% to 1.0wt%, and the content of the ε-polylysine hydrochloride is 0.05wt% to 0.3wt%.

[0006] The present invention also provides a method for preparing the fresh-keeping liquid, comprising the following steps:

[0007] (1) Wash grape seeds and spearmint separately, dry them, and grind and sieve them;

[0008] (2) Degreasing;

[0009] (3) Extraction and separation;

[0010] (4) Concentration and drying;

[0011] (5) Add ε-polylysine hydrochloride in proportion to prepare an aqueous solution.

[0012] Furthermore, the defatting process in step (2) is to mix the grape seed powder, the spearmint powder and the petroleum ether in a ratio of 1 g: 10-20 mL, shake and defatting on a shaker for 12-24 hours, and then vacuum filter and dry the filter residue to constant weight to obtain defatted grape seed powder and defatted spearmint powder.

[0013] Furthermore, the extraction process in step (3) is to mix the defatted grape seed powder and the defatted spearmint powder with a 50% to 90% ethanol solution in a ratio of 1 g: 10 to 20 mL, perform ultrasonic extraction for 2 to 5 hours, perform vacuum filtration, repeat the extraction of the filter residue three times, and combine the filtrates.

[0014] Furthermore, the ultrasonic conditions are: ultrasonic power 200-300W, ultrasonic temperature 25-50°C.

[0015] The present invention also provides application of the fresh-keeping liquid in preparing instant sea cucumber products.

[0016] The present invention also provides a method for preparing refrigerated instant sea cucumbers with improved texture and shelf life without high pressure sterilization, comprising the following steps:

[0017] (1) Sea cucumber pretreatment: Use fresh sea cucumber as raw material, remove the sand mouth, remove the internal organs, and clean inside and outside;

[0018] (2) Steaming and inactivating enzymes: Steaming the cleaned sea cucumbers;

[0019] (3) Cleaning;

[0020] (4) Soaking: Soaking the rinsed sea cucumber in the above-mentioned preservative solution;

[0021] (5) Sealed packaging: Drain the surface moisture of the sea cucumber and seal it.

[0022] Furthermore, the steaming in step (2) is to blanch the cleaned sea cucumber in hot water at 30-60°C for 30-60 seconds and then steam it for 5-15 minutes at a steaming temperature of 70-100°C.

[0023] Furthermore, in the step (4), the material-liquid ratio of sea cucumber to fresh-keeping liquid is 1 g: (5-10) mL, the soaking temperature is 0-4° C., and the soaking time is 6-24 h.

[0024] The present invention has the following beneficial effects:

[0025] The instant sea cucumber prepared by the invention has no astringency, no peculiar smell, complete shape, compact tissue, and high texture and sensory acceptance.

[0026] The present invention adopts a composite preservative liquid to improve the taste of ready-to-eat sea cucumbers, improve the quality deterioration of ready-to-eat sea cucumbers, and enhance the storage stability of ready-to-eat sea cucumbers. According to the standard of "DB 21 / 2392-2014 Local Food Safety Standard Ready-to-eat Sea Cucumbers" that the total colony count of sea cucumber products using terminal sterilization is ≤3000 CFU / g, the present invention can store ready-to-eat sea cucumbers at 4°C for ≥28 days without using terminal sterilization.

[0027] The invention adopts natural extracts which can be used for preserving instant sea cucumbers, thereby improving the storage stability and safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 Antioxidant results graph;

[0030] Figure 2 Sensory evaluation results during storage;

[0031] Figure 3 Changes in total colony count during storage;

[0032] Figure 4 Apparent morphology of ready-to-eat sea cucumbers during storage. DETAILED DESCRIPTION

[0033] Now, various exemplary embodiments of the present invention are described in detail. The methods in the examples are conventional methods unless otherwise specified, and the reagents used are conventional commercially available reagents or reagents prepared by conventional methods unless otherwise specified. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features and embodiments of the present invention.

[0034] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0035] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0036] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0037] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0038] Example 1

[0039] A preparation process of grape seed extract

[0040] Step (1) The grape seeds are cleaned, dried in a constant temperature blast drying oven at 60° C., crushed by a crusher, and passed through a 60-mesh sieve.

[0041] Step (2) grape seed powder and petroleum ether are mixed in a ratio of 1 g:15 mL, and the mixture is shaken on a shaker for defatting for 18 h, and then vacuum filtered, and the filter residue is dried to a constant weight to obtain defatted grape seed powder.

[0042] Step (3) The defatted powder was mixed with 80% ethanol solution in a ratio of 1 g: 15 mL, and ultrasonic extraction was performed for 4 h (ultrasonic power 260 W, ultrasonic temperature 45° C.), followed by vacuum filtration, and the residue was repeatedly extracted 3 times, and the filtrates were combined.

[0043] Step (4) placing the filtrate on a rotary evaporator, removing all ethanol by rotary evaporation at 55° C., concentrating and freeze-drying to obtain a grape seed extract.

[0044] Example 2

[0045] A preparation process of spearmint extract

[0046] Step (1) Clean the spearmint, dry it in a constant temperature blast drying oven at 60° C., grind it with a grinder, and then pass it through a 60-mesh sieve.

[0047] Step (2) The spearmint powder and petroleum ether are mixed in a ratio of 1 g:15 mL, and the mixture is shaken on a shaker for defatting for 15 h, and then vacuum filtered, and the filter residue is dried to a constant weight to obtain defatted spearmint powder.

[0048] Step (3) The defatted powder was mixed with 70% ethanol solution in a ratio of 1 g: 15 mL, and ultrasonic extraction was performed for 3 h (ultrasonic power 260 W, ultrasonic temperature 45° C.), followed by vacuum filtration, and the residue was repeatedly extracted 3 times, and the filtrates were combined.

[0049] Step (4) placing the filtrate on a rotary evaporator, removing all ethanol by rotary evaporation at 55° C., concentrating and freeze-drying to obtain a spearmint extract.

[0050] Example 3

[0051] A non-autoclaving and non-high pressure sterilization method for producing refrigerated instant sea cucumbers with improved texture and shelf life comprises the following steps:

[0052] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 35℃ water for 30s, then boil it in 100℃ water for 5min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0053] 2. Then prepare the preservative solution. According to the mass percentage, it contains 0.05% grape seed extract, 0.02% spearmint extract and 0.09% ε-polylysine hydrochloride, and the rest is water. According to the material-liquid ratio of 1:5 (m / V), soak the rinsed sea cucumber in the prepared preservative solution and place it at 4℃ for 12 hours.

[0054] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0055] Example 4

[0056] A non-autoclaving and non-high pressure sterilization method for producing refrigerated instant sea cucumbers with improved texture and shelf life comprises the following steps:

[0057] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 30℃ water for 45s, then boil it in 80℃ water for 8min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0058] 2. Then prepare the fresh-keeping solution. According to the mass percentage, it contains 0.1% grape seed extract, 0.06% spearmint extract and 0.18% ε-polylysine hydrochloride, and the rest is water. According to the material-liquid ratio of 1:5 (m / V), soak the rinsed sea cucumber in the prepared fresh-keeping solution and place it at 4℃ for 10 hours.

[0059] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0060] Example 5

[0061] A refrigerated instant sea cucumber production process for improving the shelf life of sea cucumbers without high pressure sterilization comprises the following steps:

[0062] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 35℃ water for 30s, then boil it in 85℃ water for 8min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0063] 2. Then prepare the fresh-keeping solution. According to the mass percentage, it contains 0.1% grape seed extract and 0.1% ε-polylysine hydrochloride, and the rest is water. According to the material-liquid ratio of 1:5 (m / V), soak the rinsed sea cucumber in the prepared fresh-keeping solution and place it at 4°C for 18 hours.

[0064] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0065] Example 6

[0066] A refrigerated instant sea cucumber production process for improving the shelf life of sea cucumbers without high pressure sterilization comprises the following steps:

[0067] 1. Select fresh sea cucumbers of similar quality and size, cut a small opening of 2-3 cm at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 45℃ water for 25s, then boil it in 100℃ water for 5min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0068] 2. Then prepare the preservative solution. According to the mass percentage, it contains 0.2% spearmint extract and 0.22% ε-polylysine hydrochloride, and the balance is water. According to the material-liquid ratio of 1:5 (m / V), soak the rinsed sea cucumber in the prepared preservative solution and place it at 4°C for 20 hours.

[0069] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0070] Comparative Example 1

[0071] The difference between this comparative example and Example 3, Example 4, Example 5 and Example 6 is that grape seed extract, spearmint extract and ε-polylysine hydrochloride preservative solution are not used.

[0072] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 35℃ water for 30s, then boil it in 100℃ water for 5min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0073] 2. Soak the rinsed sea cucumbers in pure water at a solid-liquid ratio of 1:5 (m / V) and place them at 4°C for 12 hours.

[0074] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0075] Comparative Example 2

[0076] The difference between Comparative Example 2 and Examples 3, 4, 5 and 6 is that only the preservative solution of grape seed extract is used.

[0077] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 35℃ water for 30s, then boil it in 100℃ water for 5min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0078] 2. Then prepare the preservative solution. According to the mass percentage, it contains 0.1% grape seed extract and the rest is water. According to the material-liquid ratio of 1:5 (m / V), soak the washed sea cucumber in the prepared preservative solution and place it at 4°C for 12 hours.

[0079] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0080] Comparative Example 3

[0081] The difference between Comparative Example 3 and Examples 3, 4, 5 and 6 is that only the preservative solution of spearmint extract is used.

[0082] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 35℃ water for 30s, then boil it in 100℃ water for 5min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0083] 2. Then prepare the preservative solution. According to the mass percentage, it contains 0.13% of spearmint extract and the rest is water. According to the material-liquid ratio of 1:5 (m / V), soak the washed sea cucumber in the prepared preservative solution and place it at 4°C for 12 hours.

[0084] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0085] Comparative Example 4

[0086] The difference between Comparative Example 4 and Examples 3, 4, 5 and 6 is that only the preservative solution of ε-polylysine hydrochloride is used.

[0087] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 35℃ water for 30s, then boil it in 100℃ water for 5min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0088] 2. Then prepare the fresh-keeping solution. According to the mass percentage, it contains 0.15% of ε-polylysine hydrochloride and the rest is water. According to the material-liquid ratio of 1:5 (m / V), soak the rinsed sea cucumber in the prepared fresh-keeping solution and place it at 4℃ for 12 hours.

[0089] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and you will get a ready-to-eat sea cucumber product. Store it in a refrigerator at 4°C.

[0090] Comparative Example 5

[0091] The difference between Comparative Example 5 and Examples 3, 4, 5 and 6 is that no preservative solution is used and a high pressure sterilization step is used.

[0092] 1. Select fresh sea cucumbers of similar quality and size, cut a 2-3 cm small opening at the mouth of the abdomen, remove the body fluid and internal organs inside the sea cucumber, cut off the sand mouth, and clean the inside and outside of the body wall with purified water. Blanch the cleaned sea cucumber in 35℃ water for 30s, then boil it in 100℃ water for 5min, and then rinse it under running purified water for 2min to rinse the surface clean.

[0093] 2. Soak the rinsed sea cucumbers in pure water at a solid-liquid ratio of 1:5 (m / V) and place them at 4°C for 12 hours.

[0094] 3. Take out the soaked sea cucumber, drain the surface water, put it into a packaging box, seal it tightly, and sterilize it under high pressure at 121°C for 15 minutes to obtain a ready-to-eat sea cucumber product, which should be stored in a refrigerator at 4°C.

[0095] Example 7

[0096] Determination of Antioxidant and Antibacterial Capacity of Example 1 and Example 2

[0097] Antioxidant Capacity

[0098] Determination of DPPH free radical scavenging ability: Take 1.0 mL of grape seed extract and spearmint extract of different concentrations, add 3.0 mL of 0.2 mmol / L DPPH solution, mix thoroughly, react at room temperature in the dark for 30 minutes, measure the absorbance at a wavelength of 517 nm and record it as A1; mix 1.0 mL of grape seed extract and spearmint extract of different concentrations with anhydrous ethanol, 1.0 mL of pure water, add 3.0 mL of 0.2 mmol / L DPPH solution, measure the absorbance under the same conditions and record it as A3, use VC as the positive control, repeat each sample 3 times and take the average value.

[0099] The calculation formula is as follows: DPPH free radical scavenging rate (%) = (1-(A2-A1) / A3) × 100%

[0100] Determination of ABTS free radical scavenging ability: Take 1.0 mL of grape seed extract and spearmint extract of different concentrations, add 9.0 mL of ABTS solution, mix thoroughly, react at room temperature in the dark for 5 minutes, measure the absorbance at a wavelength of 734 nm and record it as A2. Under the same conditions, use 1.0 mL of anhydrous ethanol, add 9.0 mL of ABTS solution, mix thoroughly and measure the absorbance A1. Use VC as the positive control. Repeat each sample 3 times and take the average value.

[0101] The calculation formula is as follows: ABTS free radical scavenging rate (%) = (A1–A2) / A1

[0102] ×100%

[0103] Reducing power determination: Take 1.0 mL of grape seed extract and spearmint extract of different concentrations, mix them thoroughly with 2.5 mL of 0.2 mol / L PBS with a pH of 6.6 and 1.0 mL of 1% potassium ferrocyanide solution, react at 50°C for 20 minutes, add 2.5 mL of 10% trichloroacetic acid solution after the liquid is cooled, mix thoroughly and centrifuge at a speed of 8000 r / min for 10 minutes, take 5 mL of supernatant after centrifugation, add 1 mL of 1% FeCl3 solution and 5 mL of pure water, mix and measure the absorbance at 700 nm, record it as A1, replace pure water with FeCl3 solution, and measure the absorbance value as A2.

[0104] The calculation formula is as follows: Relative total reducing capacity = A1 – A2

[0105] Antibacterial ability

[0106] Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)

[0107] The broth microdilution method was used to determine the minimum inhibitory concentration of grape seed extract, spearmint extract and ε-polylysine hydrochloride. The microbroth method was carried out in a 96-well plate. The activated bacterial solution was diluted to 10 6 CFU / mL, wells 1 to 10 in each row of the 96-well plate were the same antibacterial agent obtained by two-fold gradient dilution of LB broth, and then the bacterial solution was mixed in equal volumes to make the concentration of the bacterial solution 5×10 5 CFU / mL, well 11 contains LB broth and 10 6 The growth control group is a mixture of equal volumes of CFU / mL bacterial solution to ensure the activity of the bacterial solution. The 12th well is a blank control group with only LB broth added to detect whether the LB broth is contaminated. After the 96-well plate is placed in a constant temperature incubator at 37°C or 30°C for 18 to 24 hours, the absorbance of the bacterial solution at 600nm is measured with an enzyme marker. The concentration of the clear well with the lowest OD value combined with the sterile growth observed by naked eye is taken as the minimum inhibitory concentration. Then take 100 microliters of the minimum inhibitory concentration and the culture solution of the last three concentrations and spread them on the LB agar plate culture medium for 18 to 24 hours. The concentration corresponding to the plate without colony growth is the minimum bactericidal concentration. The specific ratios are shown in Tables 1 and 2.

[0108] Table 1 Minimum inhibitory concentration (MIC)

[0109]

[0110] Table 2 Minimum bactericidal concentration (MBC)

[0111]

[0112]

[0113] Determination of the storage period of Example 3 and Comparative Example

[0114] (1) Sensory evaluation: 10 graduate students of the food major of Ocean University of China conducted a sensory evaluation on the instant sea cucumbers prepared in Example 3 and the comparative example, and scored the smell, appearance, tissue morphology and acceptability of the instant sea cucumber products stored at 4°C. The evaluation criteria are shown in Table 3.

[0115] Table 3 Evaluation criteria

[0116]

[0117]

[0118] (2) Determination of total colony count: This shall be carried out in accordance with the method for determination of total colony count of food microorganisms in GB 4789.2-2016.

[0119] (3) TPA determination: Use a knife to cut the sea cucumber body wall into 1.0 cm × 1.0 cm size, trim the sea cucumber tubercles. Use a P / 50 cylindrical probe for the texture analyzer, set the deformation amount to 50%, the test speed to 0.6 mm / s, and measure 6 parallel samples in each group.

[0120] Table 4 Changes in hardness during storage Unit: N

[0121]

[0122]

[0123] Note: —— indicates that the sea cucumber is corrupt and cannot be measured.

[0124] Table 5 Changes in elasticity during storage Unit: mm

[0125]

[0126] Note: —— indicates that the sea cucumber is corrupt and cannot be measured.

[0127] Table 6 Changes in chewiness during storage Unit: mj

[0128]

[0129] Note: —— indicates that the sea cucumber is corrupt and cannot be measured.

[0130] (4) Appearance morphology of ready-to-eat sea cucumbers: record the state of ready-to-eat sea cucumbers during storage.

[0131] Depend on Figure 2The sensory analysis results show that the instant sea cucumber prepared using grape seed extract, spearmint extract and ε-polylysine hydrochloride preservative solution in Example 3 of the present invention has no significant changes in smell, appearance, texture and acceptability during 28 days of refrigeration at 4°C, which is better than the control example.

[0132] Depend on Figure 3 The total colony count results show that the total colony count of the instant sea cucumber prepared by using grape seed extract, spearmint extract and ε-polylysine hydrochloride preservative solution in Example 3 of the present invention increased slowly before 14 days of storage, and the bacteria began to grow after 14 days of storage. After 28 days of storage, the total colony count of Example 3 was 3.25lg cfu / g, which meets the requirement of DB 21 / 2392-2014 Food Safety Local Standard Instant Sea Cucumber that the total colony count of sea cucumber products using terminal sterilization is ≤3.47lgcfu / g. Therefore, the application of grape seed extract, spearmint extract and ε-polylysine hydrochloride preservative solution can effectively inhibit the growth of microorganisms in instant sea cucumbers and extend the shelf life.

[0133] From the results of Table 4, Table 5 and Table 6, it can be seen that on day 0, compared with the comparative example, the hardness, elasticity and chewiness of the instant sea cucumber prepared by using grape seed extract, spearmint extract and ε-polylysine hydrochloride preservative solution in Example 3 of the present invention were significantly improved, and slowly decreased with the increase of storage time. Therefore, the texture quality of the instant sea cucumber prepared by using grape seed extract, spearmint extract and ε-polylysine hydrochloride preservative solution is significantly improved.

[0134] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A sea cucumber preservative liquid, characterized in that: Includes grape seed extract, spearmint extract and epsilon-polylysine hydrochloride.

2. The fresh-keeping liquid according to claim 1, characterized in that: The content of the grape seed extract is 0.01wt% to 1.0wt%, the content of the spearmint extract is 0.01wt% to 1.0wt%, and the content of the ε-polylysine hydrochloride is 0.05wt% to 0.3wt%.

3. The method for preparing the fresh-keeping liquid according to claim 1, characterized in that: The following steps are involved: (1) Wash grape seeds and spearmint separately, dry them, and grind and sieve them; (2) Degreasing; (3) Extraction and separation; (4) Concentration and drying; (5) Add ε-polylysine hydrochloride in proportion to prepare an aqueous solution.

4. The preparation method according to claim 3, characterized in that: The defatting process in step (2) is as follows: grape seed powder, spearmint powder and petroleum ether are mixed in a ratio of 1 g: 10-20 mL, and the mixture is shaken and defatted on a shaker for 12-24 hours, and then vacuum filtered and the filter residue is dried to a constant weight to obtain defatted grape seed powder and defatted spearmint powder.

5. The preparation method according to claim 3, characterized in that: The extraction process of step (3) is to mix the defatted grape seed powder and defatted spearmint powder with 50% to 90% ethanol solution in a ratio of 1 g: 10 to 20 mL, perform ultrasonic extraction for 2 to 5 hours, perform vacuum filtration, repeat extraction of the filter residue for 3 times, and combine the filtrates.

6. The preparation method according to claim 5, characterized in that: The ultrasonic conditions are as follows: ultrasonic power of 200-300W and ultrasonic temperature of 25-50°C.

7. Use of the fresh-keeping liquid as claimed in claim 1 in preparing ready-to-eat sea cucumber products.

8. A method for preparing refrigerated ready-to-eat sea cucumbers with improved texture and shelf life without high pressure sterilization, characterized in that: The following steps are involved: (1) Sea cucumber pretreatment: Use fresh sea cucumber as raw material, remove the sand mouth, remove the internal organs, and clean inside and outside; (2) Steaming and inactivating enzymes: Steaming the cleaned sea cucumbers; (3) Cleaning; (4) Soaking: soaking the rinsed sea cucumber in the fresh-keeping solution as claimed in claim 1; (5) Sealed packaging: Drain the surface moisture of the sea cucumber and seal it.

9. The preparation method according to claim 8, characterized in that: The steaming in step (2) is to blanch the cleaned sea cucumber in hot water at 30-60°C for 30-60 seconds and then steam it for 5-15 minutes at a steaming temperature of 70-100°C.

10. The preparation method according to claim 8, characterized in that: In the step (4), the material-liquid ratio of sea cucumber to fresh-keeping liquid is 1 g: (5-10) mL, the soaking temperature is 0-4° C., and the soaking time is 6-24 h.

Images