A preservative containing insect-derived extract and its preparation method and application

Abstract

The present application belongs to the technical field of aquatic product preservation, and particularly relates to a preservative containing insect-derived extract and a preparation method and application thereof. The preservative comprises the following components in mass fraction: insect-derived protein 8-15%, insect-derived chitosan 8-25%, insect oil 4-10%, sea buckthorn seed oil 1-3%, and the balance being water. The oil phase and chitosan and protein in the preservative prepared by the present application are all extracted from the insect body or by-products, have good biocompatibility, improve the stability of the emulsion, and the insect oil and sea buckthorn seed oil are used in combination as the oil phase, which not only significantly improves the antibacterial effect on the spoilage bacteria of aquatic products, prolongs the preservation period of aquatic products, but also effectively removes the peculiar smell of aquatic products, maintains the fresh taste and the elasticity of the meat tissue. The preservative not only realizes the full utilization of insect and by-product resources, has low cost, but also is all-natural, green, non-toxic, friendly to human health and the environment, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aquatic product preservation, and specifically discloses a preservative containing insect-derived extract as well as a preparation method and application thereof. BACKGROUND

[0002] Aquatic products such as fish, shrimp, crab and the like are rich in nutrients and delicious, and contain rich unsaturated fatty acids and active substances beneficial to cardiovascular and cerebrovascular diseases, and are more and more favored by people. Since aquatic products are rich in protein and moisture, they are more likely to cause bacterial proliferation and spoilage than meat. Common spoilage bacteria of aquatic fresh products are usually Pseudomonas spp. or Shewanella putrefaciens. Once spoiled, volatile amine substances will be produced, and peculiar smell will be emitted, which is easy to cause food poisoning after eating. Common preservation methods are freezing and preservative soaking. However, freezing will cause the meat of aquatic products to be emulsified, dehydrated, dried and hardened, and the fresh taste will be greatly reduced, which greatly affects the taste. At present, preservatives basically use chemical substances such as sulfites, sodium acetate or composite phosphates, and it is difficult to ensure the safety of food. Therefore, the development and application of safe and non-toxic natural preservatives in aquatic product preservation are highly valued.

[0003] As one of the natural preservatives, plant essential oils have special composition and biological activity, and can be applied to food preservation. However, there are many limitations in the application of plant essential oils in food preservation. The bacteriostatic effect in the actual preservation process is much weaker than that in vitro, and it is necessary to increase the concentration of essential oils to achieve the preservation effect. Not only the cost is increased, but also the essential oils are easy to volatilize and oxidize, which greatly affects the smell and internal structure of food, and reduces the acceptability of food.

[0004] Insect species are rich in resources, widely distributed, and rich in nutrients such as protein, chitin, and oil. As a source of protein food, edible insects or feed products can be commercially accepted. The main edible insects are fly larvae, locusts, black soldier flies, yellow mealworms, silkworm chrysalis, and cicadas. At present, the application research on insects mainly focuses on the insect body and insect manure. The insect body can be used as high-quality protein feed, and the insect manure can be used as organic fertilizer. However, the utilization rate of insect exuviae, pupal shells, insect shells, and dead adult insects is low. The reported insect resource extracts are mainly proteins and polysaccharides, which have antioxidant and antibacterial properties. For example, insect oil is mainly used for feed / health product additives or cosmetic base oil, but there are few reports on its preservative and antibacterial effects. CN112931627A discloses that yellow mealworm protein combined with mulberry leaf extract can be used to prepare antioxidant products. The antioxidant properties of single-component yellow mealworm protein or mulberry leaf extract are weak, and the combination of the two can produce a synergistic effect, significantly improving the antioxidant effect. CN111296558A discloses that black soldier fly-derived chitosan combined with fludioxonil can be used to prepare preservatives for sugar oranges or inhibitors for citrus penicillium. However, fludioxonil is a non-systemic broad-spectrum fungicide with biological toxicity. Therefore, there is still great potential and unlimited possibilities for the comprehensive development and utilization of insect resource by-products. SUMMARY

[0005] In view of the above problems of the prior art, the present application provides a preservative containing insect-derived extracts and a preparation method and application thereof. The present application effectively prolongs the shelf life of aquatic products, maintains their original flavor, taste, and nutrients, and the whole component of the preservative is green, natural, and non-toxic, which has no effect on human health and the environment, so that the insect resources and by-products are fully utilized.

[0006] The first object of the present application is to provide a preservative containing insect-derived extracts, which comprises the following components by mass fraction: insect-derived protein 8-15%, insect-derived chitosan 8-25%, insect oil 4-10%, sea buckthorn seed oil 1-3%, and the balance is water.

[0007] Preferably, the insect source is selected from one of black soldier fly, yellow mealworm, mealworm, fly larvae, and locust.

[0008] The second object of the present application is to provide a preparation method of a preservative containing insect-derived extracts.

[0009] The above object is achieved by the following scheme, a preparation method of a preservative containing insect-derived extracts, comprising the following steps:

[0010] S1, collecting insects and their by-products, drying, and crushing for standby;

[0011] S2, the insect powder after step S1 is treated is subjected to enzymolysis by using composite enzymes alkaline protease and trypsin, centrifugation is carried out after reaction to obtain upper oil A, emulsion B, hydrolyzate C and residue D; the emulsion B and the hydrolyzate C are subjected to demulsification and then centrifugation to obtain upper oil E and solution F, the upper oils A and E are collected to obtain insect oil, the solution F is subjected to freeze drying to obtain insect-derived protein, and the residue D is subjected to decalcification, decolorization and deacetylation to obtain insect-derived chitosan;

[0012] S3, the insect-derived protein and the insect-derived chitosan obtained in step S2 are dispersed in water to obtain an aqueous phase, the insect oil obtained is mixed with sea buckthorn seed oil to obtain an oil phase, the oil phase is added to the aqueous phase and subjected to shearing homogenization and then defoaming, to obtain the preservative.

[0013] Preferably, the insect by-product in step S1 is one or more of insect skin, insect shell, pupal shell and dead adult insect.

[0014] Preferably, the enzymolysis condition in step S2 is that the temperature is 40-50 DEG C, the solid-liquid ratio is 1:5-1:10, the pH is 7.0-8.0, the enzyme amount is 0.5-0.8% of the insect powder, and the enzymolysis time is 3.5-5.5 h.

[0015] Preferably, the use amount ratio of the alkaline protease and the trypsin is 1:1-1:2, and the enzyme activity of each is 200 KU / g.

[0016] Chitosan has hydrophobicity, the amino group in the side chain is positively charged in solution due to ionization, is a typical polycationic electrolyte, can realize electrostatic interaction with protein, thereby realizing electrostatic self-assembly to form a stable complex. It is also found that the insect chitosan extracted in the application has good affinity with insect hydrolyzed protein, the insect chitosan is complexed with insect protein to act as a stabilizer of emulsion, and the emulsion stability is improved.

[0017] The extraction of the insect-derived chitosan used in the application can refer to the technical method disclosed in the patent document CN102585035A.

[0018] Preferably, the deacetylation degree of the chitosan in step S2 is greater than 65%.

[0019] Preferably, the use amount ratio of the insect-derived protein and the insect-derived chitosan in step S3 is 2:3-3:2.

[0020] The insect oil contains various fatty acids, including linoleic acid, oleic acid, lauric acid, palmitic acid and the like. At present, it has been found that part of fatty acids and their derivatives can be used as preservatives to effectively inhibit the growth and reproduction of pathogenic bacteria such as E. coli or Candida albicans, but there is no report on the research on the spoilage bacteria in aquatic products, and different strains will have certain differences in the bacteriostatic rule due to the difference in cell membrane composition.

[0021] Hippophae rhamnoides L. contains a large number of lecithin, flavones, sitosterols, SOD, vitamin E and other substances, and the sea buckthorn oil has many bioactive substances, and has high nutritional and health care values. The sea buckthorn oil reported at present has curative effects on various inflammations, and has bactericidal effects on Staphylococcus aureus, hemolytic streptococcus, typhoid bacteria, paratyphoid bacteria, dysentery bacillus and some anaerobes. The present application uses insect oil and sea buckthorn seed oil to be compounded as an oil phase, and it is found that the sea buckthorn seed oil can improve the antioxidant stability of the insect oil, and the single-component insect oil and the sea buckthorn seed oil have weak bacteriostatic effects on spoilage bacteria, but it is found that the combination of the two can significantly improve the inhibition effect on spoilage bacteria.

[0022] Preferably, the use ratio of the insect oil and the sea buckthorn seed oil in step S3 is 3:1-5:1.

[0023] The present application also provides the application of the above-mentioned preservative in the preservation of aquatic products.

[0024] Preferably, the aquatic products are shrimps, fishes and crabs.

[0025] Compared with the prior art, the excellent effects of the present application mainly embody in the following aspects:

[0026] 1. The present application uses a compound hydrolysis enzyme method to simultaneously separate insect oil, protein and chitosan, can greatly retain beneficial ingredients, and the prepared preservative emulsion does not use an emulsifier, uses insect extract chitosan as a solid particle, and has far smaller toxicity than organic surfactants, and it is found that the hydrolyzed protein and the chitosan can have a synergistic effect, significantly improve the stability of the obtained emulsion, and the emulsion is not easily affected by factors such as temperature, light, oil phase composition, and the storage time can reach more than 6 months without the phenomenon of reverse emulsion, breaking emulsion and oil separation.

[0027] 2. The oil phase, chitosan and protein in the preservative of the present application are all extracted from insects or by-products, have good biocompatibility, and the combination of the insect oil and the sea buckthorn seed oil not only significantly improves the bacteriostatic effect on spoilage bacteria of aquatic products and prolongs the preservation period of the aquatic products, but also effectively removes the peculiar smell of the aquatic products, maintains the fresh taste and the elasticity of the meat tissue.

[0028] 3. The aquatic product preservative provided by the present application not only realizes the full use of insect resources and by-products, has low cost, but also has all-natural, green and non-toxic components, is friendly to human health, and has a good application prospect. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0030] The preparation of the insect-derived chitosan in the embodiments of the present application is carried out according to the conventional conditions or the conditions recommended by the manufacturer, and the extraction of the insect-derived chitosan in the embodiments of the present application refers to the technical method disclosed in the patent document CN102585035A.

[0031] The reagents or instruments used are all conventional products that can be purchased on the market, and the manufacturers of the reagents or instruments are not specified.

[0032] Embodiment 1

[0033] A preservative containing insect-derived extract, comprising the following components by mass fraction: Hermetia illucens protein 8%, Hermetia illucens chitosan 12%, Hermetia illucens insect oil 8%, sea buckthorn seed oil 2%, and water 70%;

[0034] The preparation method of the preservative comprises the following steps:

[0035] 1. Collecting Hermetia illucens larvae, insect skins, pupal shells, and dead adult insects, washing, drying at 60°C, and crushing for use;

[0036] 2. Enzymatic hydrolysis of the Hermetia illucens insect powder treated in step 1 using a composite enzyme alkaline protease and trypsin (the use amount ratio of the alkaline protease and the trypsin is 1:2, and the enzyme activity of each is 200 KU / g). The enzyme hydrolysis conditions are as follows: temperature 45°C, solid-liquid ratio 1:5, pH 7.5, enzyme addition amount 0.5% of the mass of the Hermetia illucens insect powder, stirring speed 300 r / min, and enzyme hydrolysis time 4 h. After the reaction is completed, the enzyme is inactivated, and after cooling, centrifugation is performed at 8000 rpm for 10 min to obtain upper oil A, emulsion B, hydrolysis liquid C, and residue D. After breaking the emulsion, centrifugation is performed on the emulsion B and the hydrolysis liquid C to obtain upper oil E and solution F. The upper oils A and E are collected together as Hermetia illucens insect oil, and the solution F is freeze-dried to obtain Hermetia illucens protein. The residue D is subjected to decalcification, decolorization, and deacetylation to obtain Hermetia illucens chitosan.

[0037] 3. The Hermetia illucens protein and the Hermetia illucens chitosan obtained in step 2 are weighed according to the mass fraction of 2:3, dispersed in water to obtain an aqueous phase, and the Hermetia illucens insect oil and sea buckthorn seed oil are mixed according to the mass fraction of 4:1 to obtain an oil phase. The oil phase is slowly dropped into the aqueous phase, and after homogenization by a high-speed homogenizer at 8000 rpm for 3 min, defoaming is performed to obtain the preservative.

[0038] Embodiment 2

[0039] A preservative containing insect-derived extract, by mass fraction: black soldier fly hydrolyzed protein 13%, black soldier fly chitosan 13%, black soldier fly insect oil 7.5%, sea buckthorn seed oil 1.5%, and water 65%;

[0040] The preparation method comprises the following steps:

[0041] 1. Collect black soldier fly larvae, cuticles, pupal shells, and dead adult insects, pick and wash them, dry them at 60 DEG C, and crush them for use;

[0042] 2. Enzymatically hydrolyze the black soldier fly powder treated in step 1 using a composite enzyme alkaline protease and trypsin (the alkaline protease and trypsin are used in a ratio of 1:2, and the enzyme activity is 200 KU / g); the enzymatic hydrolysis conditions are a temperature of 45 DEG C, a material-to-liquid ratio of 1:5, a pH of 7.5, an enzyme addition amount of 0.5% of the mass of the black soldier fly powder, and a stirring speed of 300 r / min; the enzymatic hydrolysis time is 4 h; after the reaction is completed, the enzyme is inactivated, and after cooling, the mixture is centrifuged at 8000 rpm for 10 min to obtain upper oil A, emulsion B, hydrolysis liquid C, and residue D; the emulsion B and the hydrolysis liquid C are subjected to demulsification and centrifugation to obtain upper oil E and solution F; the upper oils A and E are collected and combined as black soldier fly insect oil; the solution F is freeze-dried to obtain black soldier fly protein; and the residue D is subjected to decalcification, decolorization, and deacetylation to obtain black soldier fly chitosan;

[0043] 3. Disperse the black soldier fly protein and the black soldier fly chitosan (in a ratio of 1:1) obtained in step 2 in water according to the mass fraction to obtain an aqueous phase; mix the black soldier fly insect oil with sea buckthorn seed oil (in a ratio of 5:1) to obtain an oil phase; slowly drop the oil phase into the aqueous phase, and pass the mixture through a high-speed homogenizer at 8000 rpm for 3 min to homogenize and then deaerate, thereby obtaining the preservative.

[0044] Example 3

[0045] A preservative containing insect-derived extract, by mass fraction: black soldier fly hydrolyzed protein 13%, black soldier fly chitosan 13%, black soldier fly insect oil 7.5%, sea buckthorn seed oil 1.5%, and water 65%;

[0046] The preparation method comprises the following steps:

[0047] 1. Collect black soldier fly larvae, cuticles, pupal shells, and dead adult insects, pick and wash them, dry them at 60 DEG C, and crush them for use;

[0048] 2. The black soldier fly powder processed in step 1 was enzymatically hydrolyzed using a combination of alkaline protease and trypsin (the ratio of alkaline protease to trypsin was 1:1, and the enzyme activity of each was 200 KU / g). The hydrolysis conditions were: temperature 40℃, material-to-liquid ratio 1:8, pH 8.0, enzyme dosage of 0.6% of the black soldier fly powder mass, stirring speed 300 r / min, and hydrolysis time 5 h. After the reaction was completed, the enzyme was inactivated, and after cooling, the mixture was centrifuged at 8000 rpm for 10 min to obtain upper oil A, emulsion B, hydrolysate C, and residue D. Emulsion B and hydrolysate C were demulsified and centrifuged to obtain upper oil E and solution F. Upper oil A and E were combined and collected as black soldier fly oil. Solution F was freeze-dried to obtain black soldier fly protein. Residue D was decalcified, decolorized, and deacetylated to obtain black soldier fly chitosan.

[0049] 3. Weigh the black soldier fly protein and black soldier fly chitosan obtained in step 2 according to the specified mass ratio, disperse them in water to obtain an aqueous phase, mix the obtained black soldier fly oil with sea buckthorn seed oil (in a mass ratio of 5:1) to obtain an oil phase, slowly drip the oil phase into the aqueous phase and homogenize it at 8000 rpm for 3 minutes using a high-speed homogenizer to remove bubbles, thus obtaining the preservative.

[0050] Example 4

[0051] A preservative containing insect-derived extracts comprises the following components by mass fraction: 10% hydrolyzed protein from yellow mealworms, 15% chitosan from yellow mealworms, 10% yellow mealworm oil, 2% sea buckthorn seed oil, and 63% water.

[0052] Its preparation method includes the following steps:

[0053] 1. Collect mealworm larvae, larval skins, pupal shells, and dead adult mealworms, sort and wash them, then dry them at 60℃ and crush them for later use;

[0054] 2. The mealworm powder processed in step 1 was enzymatically hydrolyzed using a combination of alkaline protease and trypsin (the ratio of alkaline protease to trypsin was 1:2, and the enzyme activity of each was 200 KU / g). The hydrolysis conditions were: temperature 45℃, material-to-liquid ratio 1:5, pH 7.5, enzyme dosage of 0.5% of the mealworm powder mass, stirring speed 300 r / min, and hydrolysis time 4 h. After the reaction was completed, the enzyme was inactivated, and after cooling, the mixture was centrifuged at 8000 rpm for 10 min to obtain upper oil A, emulsion B, hydrolysate C, and residue D. Emulsion B and hydrolysate C were demulsified and centrifuged to obtain upper oil E and solution F. Upper oil A and E were combined and collected as mealworm oil. Solution F was freeze-dried to obtain mealworm protein. Residue D was decalcified, decolorized, and deacetylated to obtain mealworm chitosan.

[0055] 3. The yellow mealworm protein obtained in step 2 and the yellow mealworm chitosan (the ratio of the amount is 2:3) are weighed according to the mass fraction and dispersed in water to obtain an aqueous phase, the yellow mealworm oil obtained is mixed with the sea buckthorn seed oil (the ratio of the amount is 5:1) to obtain an oil phase, the oil phase is slowly dropped into the aqueous phase, and the obtained product is deaerated after being homogenized by a high-speed homogenizer at 8000 rpm for 3 min, thereby obtaining the preservative.

[0056] Comparative Example 1

[0057] A preservative containing insect-derived extracts, comprising the following components in mass fraction: 8% of soybean protein isolate, 12% of black soldier fly chitosan, 8% of black soldier fly oil, 2% of sea buckthorn seed oil, and 70% of water.

[0058] The preparation method of the preservative in Comparative Example 1 is different from that in Example 1 in that the black soldier fly protein in the aqueous phase in step 3 is replaced by soybean protein isolate, and the other operation steps and parameters are the same as those in Example 1, which are not repeated here.

[0059] Comparative Example 2

[0060] A preservative containing insect-derived extracts, comprising the following components in mass fraction: 12% of black soldier fly chitosan, 8% of black soldier fly oil, 2% of sea buckthorn seed oil, and 78% of water.

[0061] The preparation method of the preservative in Comparative Example 2 is different from that in Example 1 in that the black soldier fly protein is not added in the aqueous phase in step 3, and the other operation steps and parameters are the same as those in Example 1, which are not repeated here.

[0062] Comparative Example 3

[0063] A preservative containing insect-derived extracts, comprising the following components in mass fraction: 8% of black soldier fly protein, 12% of black soldier fly chitosan, 8% of black soldier fly oil, 2% of sea buckthorn seed oil, and 70% of water.

[0064] The preparation method of the preservative in Comparative Example 3 is different from that in Example 1 in that the black soldier fly powder after step 1 is subjected to enzymatic hydrolysis by using a complex enzyme papain and trypsin (the ratio of the amount of the papain and the trypsin is 1:2, and the enzyme activity is 200 KU / g), and the other operation steps and parameters are the same as those in Example 1, which are not repeated here.

[0065] Comparative Example 4

[0066] A preservative containing insect-derived extracts, comprising the following components in mass fraction: 8% of black soldier fly protein, 12% of black soldier fly chitosan, 10% of sea buckthorn seed oil, and 70% of water.

[0067] The preservative preparation method of Comparative Example 4 is different from that of Example 1 in that the oil phase in step 3 does not add black soldier fly oil, and an equal amount of sea buckthorn seed oil is added, and other operation steps and parameters are the same as those of Example 1, which are not repeated here.

[0068] Comparative Example 5

[0069] A preservative containing insect-derived extracts, by mass fraction: black soldier fly protein 8%, black soldier fly chitosan 12%, soybean oil 8%, sea buckthorn seed oil 2%, and water 70%;

[0070] The preservative preparation method of Comparative Example 5 is different from that of Example 1 in that the oil phase in step 3 replaces black soldier fly oil with soybean oil, and other operation steps and parameters are the same as those of Example 1, which are not repeated here.

[0071] Comparative Example 6

[0072] A preservative containing insect-derived extracts, by mass fraction: black soldier fly protein 8%, black soldier fly chitosan 12%, black soldier fly oil 10%, and water 70%;

[0073] The preservative preparation method of Comparative Example 6 is different from that of Example 1 in that the oil phase in step 3 does not add sea buckthorn seed oil, and an equal amount of black soldier fly oil is added, and other operation steps and parameters are the same as those of Example 1, which are not repeated here.

[0074] Experimental Example 1: Emulsion stability determination

[0075] Test method:

[0076] The obtained emulsion is placed at 37°C under accelerated test conditions, and the emulsion stability is observed and recorded after 1, 3, and 6 months, respectively.

[0077] Table 1

[0078] Group After 1 month After 3 months After 6 months Example 1 No layering, no oiling out No layering, no oiling out No layering, no oiling out Example 2 No layering, no oiling out No layering, no oiling out No layering, no oiling out Example 3 No layering, no oiling out No layering, no oiling out No layering, no oiling out Example 4 No layering, no oiling out No layering, no oiling out No layering, no oiling out Comparative Example 1 No layering, no oiling out No layering, no oiling out Oiling out, flocculation Comparative Example 2 No layering, no oiling out Oiling out, flocculation Layering Comparative Example 3 No layering, no oiling out No layering, no oiling out Oiling out, flocculation Comparative Example 4 No layering, no oiling out No layering, no oiling out No layering, no oiling out Comparative Example 5 No layering, no oiling out No layering, no oiling out No layering, no oiling out Comparative Example 6 No layering, no oiling out No layering, no oiling out No layering, no oiling out

[0079] As shown in Table 1, the emulsion preservative prepared by the present application can maintain good stability. When the oil phase components in Comparative Examples 4-6 are changed, the stability of the emulsion does not change significantly, but when the protein components in Comparative Examples 1-3 are changed or deleted, the stability of the emulsion decreases significantly, which may be due to the good compatibility and affinity of insect-derived enzymatic protein and chitosan. When used as water phase, it can better improve the oil-water interface and effectively increase the stability of the formed emulsion.

[0080] Experimental Example 2: Bacteriostatic performance determination

[0081] Test method: The common spoilage bacteria and pathogenic bacteria in aquatic products were determined according to the evaluation method of the bacteriostatic effect described in WS / T650-2019, and the bacteriostatic rate was ≥50-90%, indicating that the bacteriostatic effect was good; and the bacteriostatic rate was ≥90%, indicating that the bacteriostatic effect was strong.

[0082] The bacteriostatic rate is shown in Table 2.

[0083] Table 2

[0084]

[0085] As shown in Table 2, the preservative emulsion prepared by the application has a strong bacteriostatic effect on spoilage bacteria and pathogenic bacteria. In Comparative Examples 1, 2 and 3, the insect protein is replaced by soybean protein isolate, no insect protein is added, or the insect protein prepared by changing the enzyme hydrolysis conditions, and the bacteriostatic ability of the emulsion preservative is significantly reduced, indicating that the insect protein prepared by the application has a significant synergistic effect on the bacteriostatic effect and the stability of the emulsion. At the same time, when the components of the preservative are changed, the bacteriostatic effect is not as good as that of the components described in the application, for example, in Comparative Example 4, the oil phase only exists in sea buckthorn seed oil, the bacteriostatic effect of the emulsion on the spoilage bacteria is weak, in Comparative Example 5, the sea buckthorn seed oil is used in combination with soybean oil, and the bacteriostatic effect is not significantly improved, and in Comparative Example 6, the oil phase only exists in insect oil, and the bacteriostatic effect on spoilage bacteria is not good, indicating that the combination of insect oil and sea buckthorn seed oil in the oil phase has a synergistic effect, which significantly enhances the bacteriostatic effect on spoilage bacteria and pathogenic bacteria.

[0086] Experimental Example 3, verification test of preservation effect

[0087] Select 550 fresh caught sea shrimps, divide them into 11 groups, 50 shrimps in each group:

[0088] Blank control group: wash the sea shrimps, drain and put them into a preservation box and store them at-2℃;

[0089] Example group and comparative example group: soak the other 10 groups of sea shrimps in the preservatives prepared in Examples 1-4 and Comparative Examples 1-6 for 10 minutes, take them out, drain and put them into a preservation box and store them at-2℃.

[0090] (1) Sensory and index evaluation of the preservation effect of sea shrimps: observe the sea shrimps in the blank group, the comparative example group and the example group every day, record the changes in the appearance of the shrimps and evaluate the sensory score. The number of people evaluating the changes in the appearance of the shrimps is 10, the score range is 1-5, the sensory evaluation standard is shown in Table 3, and the average score of each person and each sea shrimp is compared.

[0091] Table 3

[0092]

[0093] The sensory evaluation results are shown in Table 4.

[0094] Table 4

[0095]

[0096]

[0097] From Table 4, there is a significant difference between the blank group, the example group and the comparison group. The shrimp in the blank group rapidly blackens, the head and neck and the meat shell are obviously loose, and the muscle is decomposed after 3 days of refrigeration. The shrimp in the blank group has a foul smell after 5 days, and the sensory evaluation score is low. Although the decomposition rate of the shrimp in the comparison group is slower than that of the blank group, most of the shrimp in the comparison group have black spots and loose meat shells after 3 or 4 days. The shrimp in the comparison group has no fresh shrimp smell after 4 days, and has an unpleasant odor, which is below the edible range. In comparison, the shrimp in the example group has the best preservation effect. The shrimp in the example group still has a fresh shrimp smell after 7 days of refrigeration, and the meat is elastic and has no odor.

[0098] (2) Data index determination: The determination of TVB-N refers to the relevant national standards. The content of TVB-N (volatile salt-based nitrogen) is the ammonia and low-level amine produced by the decomposition of protein due to the action of enzymes and bacteria, which can be used as an evaluation index for the initial decomposition of sea shrimp. According to the GB2733-2015 standard, the content of TVB-N in seawater fish and shrimp should be ≤30mg / 100g, which is used as the freshness evaluation standard for aquatic products.

[0099] The change of TVB-N content (mg / 100g) with refrigeration time is shown in Table 5.

[0100] Table 5

[0101]

[0102]

[0103] As can be seen from Table 5, the TVB-N content of the shrimp determined by each group increases with the increase of refrigeration days. The TVB-N content of the blank group reaches 34.2mg / 100g after 3 days of refrigeration, which is not fresh according to the standard. Although the results of the comparison group are better than those of the blank group, the TVB-N content of the comparison group exceeds 30mg / 100g after 5 days, and the shrimp is no longer fresh. The TVB-N content of the shrimp treated with the emulsion preservative prepared by the present application does not exceed 30mg / 100g after 6 days, and the shrimp is considered to still maintain freshness.

[0104] From the above analysis, the prepared emulsion preservative containing insect source can effectively inhibit the growth of spoilage bacteria and pathogenic bacteria of aquatic products in the cold storage process, slow down the blackening of shrimp body and the generation of volatile odor, and significantly prolong the preservation period of aquatic products.

[0105] The embodiments of the present application are described in detail above, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A preservative containing an insect-derived extract, characterized in that, The insect-derived protein is 8-15% by mass, the insect-derived chitosan is 8-25% by mass, the insect oil is 4-10% by mass, the sea buckthorn seed oil is 1-3% by mass, and the balance is water; the insect source is selected from black soldier fly or yellow mealworm; The preservative containing insect-derived extract is obtained by a preparation method comprising the following steps: S1, collecting insects and by-products, cleaning, drying, and crushing for standby; S2, enzymatic hydrolysis of the insect powder treated in step S1 is carried out by using complex enzymes alkaline protease and trypsin, after the reaction, centrifugation is performed to obtain upper oil A, emulsion B, hydrolysis liquid C and residue D; after breaking the emulsion B and the hydrolysis liquid C, centrifugation is performed to obtain upper oil E and solution F, the upper oil A and E are collected and combined as insect oil, the solution F is freeze-dried to obtain insect-derived protein, and the residue D is subjected to decalcification, decolorization and deacetylation to obtain insect-derived chitosan; S3, dispersing the insect-derived protein and the insect-derived chitosan obtained in step S2 in water to obtain an aqueous phase, mixing the insect oil with sea buckthorn seed oil to obtain an oil phase, adding the oil phase to the aqueous phase, and degassing after shearing homogenization, to obtain the preservative.

2. The preservative according to claim 1, characterized in that, The insects and by-products in step S1 are one or more of larvae, insect skins, insect shells, pupal shells and dead adult insects.

3. The preservative according to claim 1, wherein The enzymatic hydrolysis conditions in step S2 are as follows: temperature 40-50℃, solid-liquid ratio 1:5-1:10, pH 7.0-8.0, enzyme dosage 0.5-0.8% of the mass of the insect powder, and enzymatic hydrolysis time 3.5-5.5h.

4. The preservative according to claim 1, wherein The dosage ratio of the alkaline protease and the trypsin in step S2 is 1:1-1:2, and the enzyme activity is 200KU / g.

5. The preservative of claim 1, wherein The dosage ratio of the insect-derived protein and the insect-derived chitosan in step S3 is 2:3-3:

2.

6. The preservative of claim 1, wherein The dosage ratio of the insect oil and the sea buckthorn seed oil in step S3 is 3:1-5:

1.

7. Use of the preservative containing insect-derived extract according to claim 1 for the preservation of aquatic products, characterized in that, The aquatic products are shrimp, fish and crab.

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