Integrated processing method of oncorhynchus mykiss whole fish byproducts and product thereof

Abstract

The invention relates to the field of aquatic product processing, in particular to a rainbow trout whole-fish by-product integrated processing method and a rainbow trout whole-fish by-product integrated processing product. The method comprises the following steps: carrying out continuous industrial treatment on leftovers generated in the process of processing rainbow trout fillets, sequentially adding neutral protease, alkaline protease and protease from micrococcus luteus into a pretreated solid-phase mixture for enzymolysis, separating, and respectively processing an oil phase, a water phase and a solid phase to obtain four products with high added values, a feasible process route is provided for comprehensive high-value utilization of by-products generated in the rainbow trout fillet processing process, and the rainbow trout fillet processing method has a wide market prospect.

Description

Technical Field

[0001] The invention relates to the field of aquatic product processing, and in particular to an integrated processing method for whole rainbow trout fish by-products and a product thereof. Background Art

[0002] Rainbow trout (Oncorhynchus mykiss) is a fish of the genus Salmon of the family Salmonidae. It is a fish with high economic value. Its meat is tender, delicious, and has no fishy smell. It has small bone spurs and does not need to be scaled when eaten. Rainbow trout meat is rich in unsaturated fatty acids and amino acids, which are beneficial to human absorption and nutritional balance. After more than 50 years of rapid development, China's trout farming industry has formed relatively mature reproductive regulation, breeding and breeding technologies, especially for rainbow trout. As long as the physiological conditions are suitable, the development, reproduction and hatching of fish eggs can be carried out anytime and anywhere in all regions of the country.

[0003] China's trout freshwater farming is mainly concentrated in Qinghai, Yunnan, Liaoning and Xinjiang. In recent years, China's trout freshwater farming has grown steadily. With people's love for high-quality aquatic products and the increasingly strong consumption demand in domestic and foreign markets, China's trout farming industry is strengthening the construction of farming facilities, improving farming techniques and models, advocating grazing, water-saving, low-emission, industrialized farming methods, establishing a complete set of quality and safety assurance systems, and improving the quality of farmed products; but the current processing and utilization of rainbow trout is still in a relatively primary state. Most factories develop headless and gutted rainbow trout fresh or frozen products, and in the process they produce a large amount of waste materials, such as fish heads and internal organs; further processed products such as rainbow trout fillets will also produce fish bones, fish tails, minced meat and other waste materials during the processing; the existing methods for processing waste materials include drying into fish meal for further use as feed; or composting and using it as biofertilizer. It is difficult to achieve comprehensive utilization of the whole fish in the factory and high-value utilization of rainbow trout biological resources through intensive factory design and process methods. The reason is that there are too many types of by-products, more than a dozen, which are difficult to process using a unified method. In addition, their composition is complex, they have a strong fishy smell and dark color, making them difficult to use in application scenarios such as food / pet food. If multiple by-products are processed separately, the quantity of a single category will be small, and it will be impossible to form economies of scale, resulting in high costs and difficulty in meeting production realities. Summary of the invention

[0004] The technical problem to be solved by the present invention is the comprehensive high-value utilization of by-products generated during the processing of rainbow trout fillets, especially the technical problems that there are many types of scraps, it is difficult to use a unified method to treat them, the composition is complex, the smell is strong, the color is dark, etc.

[0005] In view of the problems of the prior art, the present invention discloses an integrated processing method for whole rainbow trout by-products, wherein the waste materials generated in the process of processing rainbow trout fillets are continuously industrialized, neutral protease, alkaline protease and protease derived from Micrococcus luteus (patent CN 104894020A) are added to the pretreated solid phase mixture, and the oil phase, water phase and solid phase are processed respectively after separation to obtain four high value-added products, among which the peptide segments ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK have the characteristics of a high proportion of hydrophobic amino acids, which can be used as the source identification of rainbow trout peptides, and have a high xanthine oxidase binding ability, and can also be used in the development of products for assisting in lowering uric acid, providing a practical process route for the comprehensive high-value utilization of by-products generated in the process of processing rainbow trout fillets, and having broad market prospects.

[0006] To achieve the above object, the present invention is specifically implemented through the following technical solutions: a method for integrated processing of whole rainbow trout by-products, comprising the following steps:

[0007] (1) Dividing the waste materials generated after rainbow trout fillet processing into two parts (the traditional rainbow trout processing process includes head removal, viscera removal, and filleting. After each process step, the parts are collected separately. The first part is mainly composed of fish bones and fish skin rich in collagen, and the second part is mainly composed of fish meat and viscera without collagen), namely, the first part includes the head, bones and fish skin of rainbow trout; and the second part includes the edges, viscera, and minced meat; the first part and the second part are pre-processed respectively;

[0008] Among them, the preprocessing of the first part includes the following steps:

[0009] (1-1) Freeze the fish head, fish bones and fish skin; on the one hand, it is good for preserving freshness, and on the other hand, freezing is good for crushing, and the rigid state crushing equipment is easier to crush.

[0010] (1-2) crushing and grinding the frozen fish head, fish bones and fish skin into slurry A;

[0011] (1-3) The slurry A is subjected to high-temperature steaming and extraction, and after completion, it is separated into aqueous phase A, solid phase A, and oil phase A; the aqueous phase A mainly contains water-soluble components such as inorganic salts, amino acids, peptides, collagen, and chondroitin sulfate, the solid phase A mainly contains water-insoluble matrix proteins, ash, etc., and the oil phase A mainly contains fat-soluble components such as fish oil.

[0012] The second part of the pretreatment includes the following steps: grinding the viscera and minced meat of rainbow trout into a slurry B;

[0013] (2) Solid phase A and slurry B are mixed to obtain a solid phase mixture, and neutral protease, alkaline protease and protease from Micrococcus luteus are added to the solid phase mixture in sequence for enzymatic hydrolysis. The three enzymes are added in sequence. Neutral protease has high activity under neutral conditions and has a wide range of specificity, and can hydrolyze protein-rich substrates of rainbow trout; alkaline protease has different cleavage sites from neutral protease, which can further reduce the molecular weight of protein peptides; protease from Micrococcus luteus finally further hydrolyzes the enzymatic hydrolysis products treated by the above two enzymes. Under the action of the mixture of the above three proteases, the molecular weight of protein peptides can be further reduced, and the digestion and absorption rate of protein can be improved. The addition amount is 1-5‰ of the substrate mass, the enzymatic hydrolysis temperature is 50-60℃, and the enzymatic hydrolysis time is 1-2h. After enzymatic hydrolysis, separation is completed to obtain aqueous phase B, solid phase B and oil phase B. Aqueous phase B is mainly an emulsion composed of polypeptides and water-soluble proteins, solid phase B is mainly matrix proteins and non-protein components that are difficult to hydrolyze, and oil phase B is mainly visceral fat and oil rich in vitamins A and D.

[0014] (3) Each component is purified separately to obtain a product; wherein,

[0015] The aqueous phase A is purified to obtain product A, which is mainly collagen.

[0016] The oil phase A is combined with the oil phase B, and refined to obtain product B, which is crude fish oil;

[0017] The aqueous phase B is purified to obtain product C, which is a hydrolyzate;

[0018] The solid phase B is dried and then ultrafinely ground to obtain product D, which is a biological calcium complex.

[0019] Furthermore, the freezing method in step (1-1) is frozen plate freezing or cold air freezing, each raw material is frozen separately or multiple raw materials are mixed and frozen; the freezing temperature is ≤18°C; and the freezing time is ≥24h.

[0020] Furthermore, the crushing method in step (1-2) is graded crushing, using a crusher for preliminary crushing, and then using a meat grinder to further crush the frozen block; then using a wet grinder for grinding, and finally using a bone mud grinder for grinding to obtain slurry A. Grinding can reduce the particle size of the material, improve the reaction efficiency of hot water extraction and enzymatic hydrolysis, and the mesh size after crushing is 40-60 meshes.

[0021] Furthermore, the parameters of high temperature cooking and extraction in step (1-3) are: temperature 70-150°C, pressure 0.1-0.5MPa, time control 0.5-5h; the separation equipment adopts a three-phase centrifuge. High temperature cooking and extraction can dissolve water-soluble collagen and separate oil and protein; the separation adopts the pressing / centrifugation method, and the separation of emulsion and oil is carried out by a continuous three-phase centrifuge at a speed of 4500r / min.

[0022] Furthermore, in the second part of the pretreatment of step (1), the viscera and minced meat of the rainbow trout are ground into a slurry; the viscera and minced meat are crushed with a meat grinder, then ground with a wet grinder, and finally ground with a bone mud grinder to obtain slurry B.

[0023] Furthermore, the separation equipment in step (2) adopts a three-phase centrifuge with a rotation speed of 4500r / min for continuous separation.

[0024] Furthermore, the refining process of the aqueous phase A in step (3) includes decolorization, deodorization, and desalination steps, including membrane separation and reduced pressure concentration, and then drying or not drying to obtain product A. Decolorization is performed by filtering and decolorization using activated carbon and diatomaceous earth, the diatomaceous earth is 200-400 mesh, and the activated carbon is 0.4-0.6mm carbon powder; deodorization adopts a method of high-density carbon dioxide introduction and high vacuum degree; desalination adopts nanofiltration desalination, and the molecular weight of the nanofiltration membrane is 300kDa; the operating temperature of decolorization and deodorization is 60-80 degrees Celsius, and the nanofiltration is below 30 degrees Celsius.

[0025] Furthermore, in step (3), the refining process of oil phase A and oil phase B is to heat the fish oil to 60-80° C. under vacuum conditions, add activated clay while stirring, the amount of activated clay added is 3-15%, stir thoroughly for 10-30 minutes, and separate by filtering or centrifugation after stirring, at 4500 r / min, to obtain decolorized fish oil, i.e., product B.

[0026] Furthermore, the refining process of the aqueous phase B in step (3) is thermal reaction, deodorization, desalination, concentration, and drying or not drying to obtain the product C. The Maillard reaction thermal reaction is 90-100 degrees Celsius, heated for 10-30 minutes, and the Maillard reaction is carried out; the deodorization is vacuum degree -0.04MPa, 80 degrees Celsius treatment for 20 minutes; the desalination adopts a nanofiltration membrane separation method, the molecular weight of the nanofiltration membrane is 300kDa-500kDa, and the concentration adopts a vacuum thin film evaporation device at a temperature of 80 degrees Celsius, and the operation is continuous; the drying adopts spray drying, the inlet air temperature is 180 degrees Celsius, and the outlet air temperature is 90 degrees Celsius.

[0027] Furthermore, in step (3), the solid phase B is purified by freeze drying or microwave drying, and then ultrafinely crushed to a size of more than 200 meshes to obtain product D. Drying is for dehydration, and ultrafinely crushing is for improving its application performance and making it have a better taste when developing products. The powder after crushing is less than 200 meshes.

[0028] The products prepared by the above method include product A, product B, product C and product D; wherein product A is an extract, mainly collagen, with a protein content of ≥65% and a chondroitin sulfate of ≥2%; product B is crude fish oil, with a linoleic acid content of ≥25% and an oleic acid content of ≥25%; product C is a hydrolyzate, with a protein content of ≥65%, a proportion of peptides with a relative molecular mass of less than 10,000 / % of ≥80%, an ash content of ≤5%, and containing characteristic peptide sequences ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK; product D is a biological calcium complex, with a calcium content of ≥8000 mg / kg and a magnesium content of ≥500 mg / kg.

[0029] Furthermore, the sequences ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK have the ability to inhibit xanthine oxidase and can be used in the development of products that assist in lowering uric acid.

[0030] The beneficial effects of the present invention are:

[0031] (1) The present invention uses neutral protease, alkaline protease and protease derived from Micrococcus luteus for enzymatic hydrolysis in sequence. Under the action of the mixture of the three proteases, the molecular weight of the protein peptide can be further reduced, and the digestion and absorption rate of the protein can be improved.

[0032] (2) It is possible to produce related products from rainbow trout biological raw materials, realize the comprehensive utilization of rainbow trout, increase the added value of rainbow trout by-products, and improve the deep processing level of the rainbow trout industry.

[0033] (3) The present invention obtains two peptide sequences, ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK, which have xanthine oxidase inhibitory effects and can be used in the development of products that assist in lowering uric acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a process flow chart of the present invention.

[0035] Figure 2 The figure is a comparison of the degree of protein hydrolysis of the solid phase mixture obtained by mixing the solid phase A and the slurry B of the present invention. DETAILED DESCRIPTION

[0036] The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0037] The following examples can be understood as a part of the local structure or method of the present invention alone, and can also be understood as the combination of the examples to explain the connotation of the larger structure or method of the present invention. Unless otherwise specified, all raw materials of the present invention are obtained from commercial sales.

[0038] Embodiment 1:

[0039] An integrated processing method for whole rainbow trout by-products, characterized by comprising the following steps:

[0040] (1) dividing the waste material generated after rainbow trout fillet processing into two parts, namely, a first part including the head, bones and skin of rainbow trout and a second part including the edges, viscera and minced meat; and pre-processing the first part and the second part respectively;

[0041] Among them, the preprocessing of the first part includes the following steps:

[0042] (1-1) Freezing the fish head, fish bones and fish skin; the freezing method is freezing on a frozen plate or freezing with cold air, freezing each raw material separately or freezing a mixture of multiple raw materials; the freezing temperature is ≤18°C; the freezing time is ≥24h;

[0043] (1-2) crushing and grinding the frozen fish head, fish bones and fish skin into slurry A; the crushing method is graded crushing, using a crusher for preliminary crushing, and then using a meat grinder to further crush the frozen block; then using a wet grinder to grind, and finally using a bone mud grinder to grind to obtain slurry A;

[0044] (1-3) The slurry A is subjected to high-temperature cooking and extraction, and after completion, the slurry is separated into a water phase A, a solid phase A and an oil phase A; the parameters of the high-temperature cooking and extraction are: temperature 70-150°C, pressure 0.1-0.5MPa, and time control 0.5-5h; the separation equipment adopts a three-phase centrifuge.

[0045] The second part of the pretreatment includes the following steps: grinding the viscera and minced meat of rainbow trout into slurry B; grinding the viscera and minced meat of rainbow trout into slurry; crushing the viscera and minced meat with a meat grinder, then grinding them with a wet grinder, and finally grinding them with a bone mud grinder to obtain slurry B.

[0046] (2) The solid phase A is mixed with the slurry B to obtain a solid phase mixture, and neutral protease, alkaline protease and protease derived from Micrococcus luteus are added to the solid phase mixture in turn for enzymatic hydrolysis. The addition amount is 1-5‰ of the substrate mass, the enzymatic hydrolysis temperature is 50-60°C, and the enzymatic hydrolysis time is 1-2h. After the enzymatic hydrolysis, a three-phase centrifuge is used to separate the aqueous phase B, the solid phase B and the oil phase B. The aqueous phase B is mainly an emulsion composed mainly of polypeptides and water-soluble proteins, the solid phase B is mainly matrix proteins and non-protein components that are difficult to hydrolyze, and the oil phase B is mainly visceral fat and oil rich in vitamins A and D.

[0047] (3) Each component is purified to obtain a product; wherein,

[0048] The aqueous phase A is refined to obtain product A; the refining process includes decolorization, deodorization, and desalination steps, including membrane separation and reduced pressure concentration, and then product A is obtained by drying or not drying.

[0049] The oil phase A and the oil phase B are combined and refined to obtain preparation B; the refining process of the oil phase A and the oil phase B is to heat the fish oil to 60-80°C under vacuum conditions, add activated white clay while stirring, the white clay addition amount is 3-15%, stir thoroughly for 10-30 minutes, and separate by filtering or centrifugation after the stirring is completed to obtain decolorized fish oil, i.e., product B.

[0050] The aqueous phase B is refined to obtain product C; product C is obtained by thermal reaction, deodorization, desalination, concentration, and drying or non-drying.

[0051] The solid phase B is dried and then ultra-finely ground to obtain product D. The solid phase B is freeze-dried or microwave-dried, and then ultra-finely ground to a size of more than 200 meshes to obtain product D.

[0052] Comparative Example:

[0053] In step (2), an equal amount of neutral protease, an equal amount of alkaline protease and an equal amount of neutral protease + alkaline protease are used. Neutral protease (Longkote neutral protease, enzyme activity ≥ 60,000 u), alkaline protease (Longkote alkaline protease, enzyme activity ≥ 100,000 u); the rest is the same as in Example 1. Comparison of protein hydrolysis degree determined by ninhydrin method Figure 2 As shown, the enzymatic hydrolysis effect of the three enzyme combinations further improved the degree of protein hydrolysis.

[0054] Application examples:

[0055] The peptides ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK contained in the product C in Example 1 have binding energies of -10.3 kJ / mol and -8.7 kJ / mol with xanthine oxidase, respectively, and have good binding abilities.

[0056] The peptides in P4 were semi-flexibly docked with xanthine oxidase using the Auto dock molecular docking software. The results showed that the binding energies of peptides ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK with xanthine oxidase were -10.3 kJ / mol and -8.7 kJ / mol, respectively, which showed good binding ability and could effectively inhibit the synthesis of uric acid.

[0057] The various aspects, embodiments, and features of the present invention should be considered to be illustrative in all aspects and not limiting of the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0058] In the preparation method of the present invention, the order of each step is not limited to the order listed. For those skilled in the art, without creative work, the order of each step is also within the protection scope of the present invention. In addition, two or more steps or actions can be performed simultaneously.

[0059] Finally, it should be noted that the specific embodiments described herein are merely examples of the present invention, and are not intended to limit the implementation methods of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described, or replace them in a similar manner. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A method for integrated processing of rainbow trout whole fish by-products, characterized in that The following steps are involved: (1) dividing the waste material generated after rainbow trout fillet processing into two parts, namely, a first part including the head, bones and skin of rainbow trout and a second part including the edges, viscera and minced meat; and pre-processing the first part and the second part respectively; Among them, the preprocessing of the first part includes the following steps: (1-1) Freezing fish heads, fish bones and fish skins; (1-2) crushing and grinding the frozen fish head, fish bones and fish skin into slurry A; (1-3) subjecting slurry A to high-temperature cooking and extraction, and separating to obtain water phase A, solid phase A and oil phase A; The second part of the pretreatment includes the following steps: grinding the viscera and minced meat of rainbow trout into a slurry B; (2) mixing solid phase A with slurry B to obtain a solid phase mixture, and sequentially adding neutral protease, alkaline protease and protease derived from Micrococcus luteus to the solid phase mixture for enzymolysis, wherein the addition amount is 1-5‰ of the substrate mass, the enzymolysis temperature is 50-60°C, and the enzymolysis time is 1-2h; after enzymolysis, separation is completed to obtain aqueous phase B, solid phase B and oil phase B; (3) Each component is purified to obtain a product; wherein, Refining the aqueous phase A to obtain product A; The oil phase A and the oil phase B are combined and refined to obtain Preparation B; Refining the aqueous phase B to obtain product C; The solid phase B is dried and then ultrafinely ground to obtain product D.

2. The processing method according to claim 1, characterized in that: The freezing method in step (1-1) is frozen plate freezing or cold air freezing, each raw material is frozen separately or multiple raw materials are mixed and frozen; the freezing temperature is ≤18°C; and the freezing time is ≥24h.

3. The processing method according to claim 1, characterized in that: The crushing method in step (1-2) is graded crushing, using a crusher for preliminary crushing, and then using a meat grinder to further crush the frozen block; then using a wet grinder for grinding, and finally using a bone mud grinder for grinding to obtain slurry A.

4. The processing method according to claim 1, characterized in that: The parameters of high temperature cooking and extraction in step (1-3) are: temperature 70-150° C., pressure 0.1-0.5 MPa, time control 0.5-5 h; and the separation equipment adopts a three-phase centrifuge.

5. The processing method according to claim 1, characterized in that: Step (1) the second part of the pretreatment is to grind the viscera and minced meat of rainbow trout into a slurry; The viscera and minced meat are crushed with a meat grinder, then ground with a wet grinder, and finally ground with a bone mud mill to obtain slurry B.

6. The processing method according to claim 1, characterized in that: The refining process of the aqueous phase A in step (3) includes decolorization, deodorization, and desalination steps, including membrane separation and reduced pressure concentration, and then product A is obtained by drying or not drying.

7. The processing method according to claim 1, characterized in that: The refining process of the oil phase A and the oil phase B in step (3) is to heat the fish oil to 60-80° C. under vacuum conditions, add activated clay while stirring, the amount of clay added is 3-15%, and stir thoroughly for 10-30 minutes. After stirring, separate by filtering or centrifugation to obtain decolorized fish oil, i.e., product B; the refining process of the aqueous phase B is thermal reaction, deodorization, desalination, concentration, drying or non-drying to obtain product C; the refining process of the solid phase B is freeze drying or microwave drying, and then ultrafine grinding to more than 200 meshes to obtain product D.

8. The product prepared by any one of the processing methods of claims 1 to 7, characterized in that: Including product A, product B, product C and product D; among them, product A is an extract with a protein content of ≥65% and chondroitin sulfate ≥2%; product B is crude fish oil with a linoleic acid content of ≥25% and an oleic acid content of ≥25%; product C is a hydrolyzate with a protein content of ≥65%, a proportion of peptides with a relative molecular mass of less than 10,000 / % of ≥80%, an ash content of ≤5%, and contains characteristic peptide sequences ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK; product D is a biological calcium complex with a calcium content of ≥8000 mg / kg and a magnesium content of ≥500 mg / kg.

9. Use of the peptide sequences ATDFVVSKPGTFK and DAAPAVAGAPGAPISVK described in claim 8 in the preparation of auxiliary uric acid lowering products.

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