Oyster juice and preparation method thereof

Abstract

The invention relates to oyster juice and a preparation method thereof in the field of biochemistry. The preparation method comprises the following steps: mixing oyster meat and water, and homogenizing to prepare oyster slurry; performing first-stage enzymolysis on a mixture of the oyster slurry and protease to prepare a first enzymolysis product; the protease comprises flavourzyme, alkaline protease, papain and trypsin; the mass ratio of the protease to the oyster slurry is (0.003-0.006): 1; adjusting the pH value of the first enzymatic hydrolysate to 8.0-8.5, and carrying out a high-temperature reaction at 94.5-95.5 DEG C for 1.5-2.5 h to prepare a high-temperature reaction product; performing second-stage enzymolysis on a mixture of the high-temperature reaction product and polysaccharide lyase to prepare a second enzymolysis product; the mass ratio of the polysaccharide lyase to the high-temperature reaction product is (0.0025-0.0035): 1; separating enzymolysis clear liquid from the second enzymolysis product, and cooking to prepare the oyster juice. According to the preparation method, reducing sugar does not need to be additionally added.

Description

Technical Field

[0001] The present application relates to the field of biochemistry, and in particular to oyster juice and a preparation method thereof. Background Art

[0002] The oyster juice industry standard SB / T 11191 clearly states that oyster juice is a product made from oysters through steaming, concentration and salting. Currently, the production of oyster juice mainly involves steaming and enzymatic hydrolysis. The yield of steaming is low, and the industry has generally switched to enzymatic hydrolysis.

[0003] At present, the preparation process of oyster juice tends to use protein enzyme preparations. Although they can degrade proteins into short peptides and amino acids, they cannot completely open the connecting bonds between sugar chains and peptide chains, thus failing to fully dissolve the glycogen in glycoproteins. In addition, the glycogen contained in these oyster enzymatic hydrolysates mostly exists in the form of polysaccharides.

[0004] The oyster hydrolysate prepared by traditional technology has a low reducing sugar content, generally at the level of 2%-3%. In order to improve the flavor of the oyster hydrolysate, which has a strong fishy smell and a bitter aftertaste, it is often necessary to add additional reducing sugars such as ribose, xylose, and glucose to the oyster hydrolysate, so that the reducing sugars react with amino acids to produce aroma and flavor, and use the aroma and flavor to modify the insufficient flavor of the oyster hydrolysate. Based on this, in the process of oyster juice preparation, how to increase the reducing sugar yield of the process itself to avoid the addition of additional reducing sugars is an urgent problem to be solved. Summary of the invention

[0005] One or more embodiments of the present application provide an oyster sauce and a preparation method and application thereof, including the following technical solutions:

[0006] One or more embodiments of the present application provide a method for preparing oyster sauce, the preparation method comprising the following steps:

[0007] Mix oyster meat and water, and homogenize to prepare oyster slurry;

[0008] The mixture of the oyster slurry and the protease is subjected to a first stage of enzymolysis to prepare a first enzymolysis product; the protease comprises flavor protease, alkaline protease, papain and trypsin; the mass ratio of the protease to the oyster slurry is (0.003-0.006):1;

[0009] Adjusting the pH value of the first enzymatic hydrolysis product to 8.0-8.5 and subjecting the product to a high temperature reaction at 94.5° C.-95.5° C. for 1.5 h-2.5 h to prepare a high temperature reaction product;

[0010] The mixture of the high temperature reaction product and the polysaccharide lyase is subjected to a second stage of enzymolysis to prepare a second enzymolysis product; the mass ratio of the polysaccharide lyase to the high temperature reaction product is (0.0025-0.0035):1; and,

[0011] The enzymatic hydrolysis clear liquid is separated from the second enzymatic hydrolysis product, boiled, and salt is added to prepare oyster juice.

[0012] In some embodiments of the present application, the mass ratio of the flavor protease, the alkaline protease, the papain and the trypsin is 1:(1.5-2.5):(0.8-1.2):(0.8-1.2).

[0013] In some embodiments of the present application, the polysaccharide lysing enzyme includes α-amylase, β-amylase, isoamylase and glycosidase.

[0014] In some embodiments of the present application, the mass ratio of the α-amylase, β-amylase, isoamylase and glycosidase is 1:(0.8-1.2):(0.8-1.2):(2.8-3.3).

[0015] In some embodiments of the present application, the mass ratio of the oyster meat to the water is 1:(2-3).

[0016] In some embodiments of the present application, the homogenization conditions include: a rotation speed of 3500 rpm-4500 rpm and a time of 4.5 min-5.5 min.

[0017] In some embodiments of the present application, the enzymatic hydrolysis conditions of the first stage include: temperature of 55° C.-58° C., initial pH of 6.0-6.5, and time of 8 h-10 h.

[0018] In some embodiments of the present application, the enzymatic hydrolysis conditions of the second stage include: temperature of 30° C.-35° C., initial pH of 7.0-7.5, and time of 4 h-5 h.

[0019] In some embodiments of the present application, the method of separating the enzymatic supernatant comprises centrifugation.

[0020] In some embodiments of the present application, the centrifugal conditions include: a rotation speed of 3500 rpm-4500 rpm, and a time of 4.5 min-5.5 min.

[0021] In some embodiments of the present application, the cooking conditions include: normal pressure, temperature of 98° C.-102° C., and time of 1 h-2 h.

[0022] In some embodiments of the present application, the amount of the salt is 8wt%-12wt% of the enzymatic hydrolysis solution.

[0023] In some embodiments of the present application, the preparation method further comprises the step of performing enzyme inactivation treatment after the first stage enzymatic hydrolysis and / or the second stage enzymatic hydrolysis is completed.

[0024] In some embodiments of the present application, the enzyme inactivation treatment adopts a high temperature enzyme inactivation method.

[0025] In some embodiments of the present application, the conditions of the high temperature enzyme inactivation method include: temperature of 98°C-105°C and time of 8min-12min.

[0026] One or more embodiments of the present application also provide oyster sauce prepared by the preparation method.

[0027] The details of one or more embodiments of the present application are set forth in the description which follows, and other features, objects, and advantages of the present application will be apparent from the description and its claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0029] Figure 1 This is a process flow chart of an embodiment of the present application;

[0030] Figure 2 The sensory evaluation analysis results of oyster juice provided in the examples and comparative examples of the present application are shown. DETAILED DESCRIPTION

[0031] The present application will be further described in detail below in conjunction with the accompanying drawings, embodiments and examples. It should be understood that these embodiments and examples are only used to illustrate the present application and are not used to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the understanding of the disclosure of the present application more thorough and comprehensive. It should also be understood that the present application can be implemented in many different forms, is not limited to the embodiments and examples described herein, and those skilled in the art can make various changes or modifications without violating the connotation of the present application, and the equivalent form obtained also falls within the protection scope of the present application. In addition, in the description below, a large number of specific details are given in order to provide a more comprehensive understanding of the present application, and it should be understood that the present application can be implemented without one or more of these details.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing implementation modes and embodiments and are not intended to limit this application.

[0033] the term

[0034] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0035] The terms "and / or", "or / and", and "and / or" used in this article include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0036] In the present application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0037] As used herein, "combination thereof", "any combination thereof", "any combination thereof" etc. include all suitable combinations of any two or more of the listed items.

[0038] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0039] Herein, “preferred”, “better”, “more preferred” and “suitable” are merely used to describe implementation methods or examples with better effects, and it should be understood that they do not constitute limitations on the scope of protection of this application.

[0040] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0041] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0042] In the present application, the terms "first", "second", "third", "fourth", etc. in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0043] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0044] In the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In this article, it is equivalent to directly listing each integer, such as t is an integer selected from 1 to 10, indicating that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0045] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0046] In the present application, % (w / w) and wt% both represent weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass volume percentage.

[0047] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0048] Most existing oyster glycogen extraction technologies use enzymatic hydrolysis to extract oyster polysaccharides using proteases and amylases, while there is currently no report on the further processing of oyster polysaccharides into reducing sugars. Based on the study of oyster proteinase hydrolysis, this application focuses on the further hydrolysis of oyster polysaccharides into monosaccharides to provide sufficient reducing sugar substrates for the subsequent aroma-generating reaction of oyster juice.

[0049] In a first aspect of the embodiments of the present application, a method for preparing oyster sauce is provided, the method comprising the following steps:

[0050] Mix oyster meat and water, and homogenize to prepare oyster slurry;

[0051] The mixture of the oyster slurry and the protease is subjected to a first stage of enzymolysis to prepare a first enzymolysis product; the protease comprises flavor protease, alkaline protease, papain and trypsin; the mass ratio of the protease to the oyster slurry is (0.003-0.006):1;

[0052] Adjusting the pH value of the first enzymatic hydrolysis product to 8.0-8.5 and subjecting the product to a high temperature reaction at 94.5° C.-95.5° C. for 1.5 h-2.5 h to prepare a high temperature reaction product;

[0053] The mixture of the high temperature reaction product and the polysaccharide lyase is subjected to a second stage of enzymolysis to prepare a second enzymolysis product; the mass ratio of the polysaccharide lyase to the high temperature reaction product is (0.0025-0.0035):1; and,

[0054] The enzymatic hydrolysis clear liquid is separated from the second enzymatic hydrolysis product, boiled, and salt is added to prepare oyster juice.

[0055] The present application selects a highly efficient composite protease to act on high-glycogen oyster raw materials for enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the pH value of the system is adjusted and high-temperature treatment is performed to destroy the covalent bonds between the animal polysaccharide sugar chains and peptide chains and improve the dissolution of the polysaccharide. Then, a highly efficient polysaccharide lyase is screened out to act on the system to increase the reducing sugar content of the oyster juice. In the back-end aroma reaction, there is no need to add additional exogenous reducing sugars, and the taste and aroma can already meet the reaction requirements.

[0056] The oysters are first hydrolyzed by a composite protease, and then the pH value of the oyster hydrolysate is adjusted and the high temperature reaction is carried out to destroy the covalent bonds between the sugar chains and peptide chains of the animal polysaccharide and improve the dissolution of oyster polysaccharides.

[0057] A segmented gradient enzymatic hydrolysis process is adopted, in which the first stage adopts the first stage composite protease enzymatic hydrolysis, and the second stage uses polysaccharide lyase to decompose oyster polysaccharides (for example, the reducing sugar content of the oyster juice generated in one embodiment is above 3.4%, which is 12% higher than the reducing sugar content of conventional oyster juice). The Maillard flavor reaction can be achieved without the need to add additional reducing sugar, and oyster juice with high sweetness and low fishy smell is produced.

[0058] In some examples, the mass ratio of the flavor protease, the alkaline protease, the papain and the trypsin is 1:(1.5-2.5):(0.8-1.2):(0.8-1.2). For example, 1:1.5:1.2:0.8, 1:1.5:0.8:0.8, 1:1.5:0.8:1.2, 1:1.5:1.2:1.2, 1:1.5:1:0.8, 1:1.5:1:1.2, 1:2.5:1.2:0.8, 1:2.5:0.8:0.8, 1:2.5:0.8:1.2, 1:2.5:1.2:1.2, 1:2.5:1:0.8, 1:2.5:1:1.2, 1:2:1.2:0.8, 1:2:0.8:0.8, 1:2:0.8:1.2, 1:2:1.2:1.2, 1:2:1:0.8, 1:2:1:1.2.

[0059] In some examples, the polysaccharide lyase includes α-amylase, β-amylase, isoamylase and glycosidase; optionally, the mass ratio of the α-amylase, β-amylase, isoamylase and glycosidase is 1:(0.8-1.2):(0.8-1.2):(2.8-3.3). For example, 1:0.8:1.2:2.8, 1:0.8:0.8:2.8, 1:0.8:0.8:3.3, 1:0.8:1.2:3.3, 1:0.8:1:2.8, 1:0.8:1:3.3, 1:1:1.2:2.8, 1:1:0.8:2.8, 1:1:0.8:3.3, 1:1:1.2:3.3, 1:1:1:2.8, 1:1:1:3.3, 1:1.2:1.2:2.8, 1:1.2:0.8:2.8, 1:1.2:0.8:3.3, 1:1.2:1.2:3.3, 1:1.2:1:3.3, 1:1.2:1:3.3.

[0060] In some of the examples, the mass ratio of the oyster meat to the water is 1:(2-3), for example, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3.

[0061] In some examples, the homogenization conditions include: a rotation speed of 3500-4500 rpm (for example, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500 rpm) and a time of 4.5-5.5 min (for example, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5 min).

[0062] In some of the examples, the enzymatic hydrolysis conditions of the first stage include: a temperature of 55°C-58°C (for example, 55, 55.5, 56, 56.5, 57, 57.5, 58°C), an initial pH of 6.0-6.5 (for example, 6, 6.1, 6.2, 6.3, 6.4, 6.5), and a time of 8h-10h (for example, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4, 9.6, 9.8, 10h).

[0063] In some of the examples, the enzymatic hydrolysis conditions of the second stage include: a temperature of 30°C-35°C (for example, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34, 34.5, 35°C), an initial pH of 7.0-7.5 (for example, 7, 7.1, 7.2, 7.3, 7.4, 7.5), and a time of 4h-5h (for example, 4, 4.2, 4.4, 4.6, 4.8, 5h).

[0064] In some examples, the method for separating the enzymatic hydrolysis supernatant includes centrifugation; optionally, the centrifugation conditions include: a rotation speed of 3500rpm-4500rpm (for example, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500rpm), and a time of 4.5min-5.5min (for example, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5min).

[0065] In some examples, the cooking conditions include: normal pressure, temperature of 98°C-102°C (for example, 98, 98.5, 99, 99.5, 100, 100.5, 101, 101.5, 102°C), and time of 1h-2h (for example, 1, 1.2, 1.4, 1.6, 1.8, 2h).

[0066] In some examples, the amount of salt used is 8wt%-12wt% of the enzymatic hydrolysis solution, for example, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%, 10.5wt%, 11wt%, 11.5wt%, 12wt%.

[0067] In some of the examples, the preparation method also includes the step of performing an enzyme inactivation treatment after the first stage enzymatic hydrolysis or / and the second stage enzymatic hydrolysis; optionally, the enzyme inactivation treatment adopts a high temperature enzyme inactivation method; further optionally, the conditions of the high temperature enzyme inactivation method include: a temperature of 98°C-105°C (for example, 98, 98.5, 99, 99.5, 100, 100.5, 101, 101.5, 102, 10.2.5, 103, 103.5, 104, 104.5, 105°C), and a time of 8min-12min (for example, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12min).

[0068] The second aspect of the embodiments of the present application provides oyster sauce prepared by the preparation method described in the first aspect.

[0069] The embodiments of the present application will be described in detail below in conjunction with examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are preferably referred to the guidance provided in the present application, and can also be based on the experimental manual or normal conditions in this area, can also be based on the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0070] In the following specific embodiments, the measured parameters of raw material components may have slight deviations within the range of weighing accuracy unless otherwise specified. For temperature and time parameters, acceptable deviations caused by instrument test accuracy or operation accuracy are allowed.

[0071] Example 1

[0072] This embodiment provides an oyster sauce and a preparation method thereof, including the following contents:

[0073] (1) Oyster shelling and impurity removal → (2) Homogenization → (3) First stage enzymatic hydrolysis (complex protease) → (4) Enzyme inactivation → (5) pH adjustment → (6) High temperature reaction → (7) Second stage enzymatic hydrolysis (polysaccharide lyase) → (8) Enzyme inactivation → (9) Centrifugal separation → (10) Cooking to produce aroma → Oyster juice. Figure 1 .

[0074] Specifically:

[0075] (2) Homogenization: The oysters were shelled and impurities removed, and the oyster meat was homogenized for 5 min using a shearing machine at 4000 rpm in a ratio of oyster meat to water = 1:2.5 (mass ratio) to prepare oyster slurry.

[0076] (3) First-stage proteolysis, (4) enzyme inactivation: adding a composite protease to the oyster slurry for enzymolysis, wherein the composite protease: oyster slurry = 0.005:1 (mass ratio), enzymolysis at 56°C, pH 6.3 for 9 hours, after the reaction is completed, inactivation treatment is performed at 100°C for 10 minutes, and cooling to room temperature to prepare a first enzymolysis product. The composite protease is composed of flavor protease, alkaline protease, papain, and trypsin in a mass ratio of 1:2:1:1.

[0077] (5) Adjusting pH; (6) High-temperature reaction: adjusting the pH value of the first enzymatic hydrolysis product to 8.5, and keeping it at 95° C. for 2 h to prepare a high-temperature reaction product.

[0078] (7) Second stage enzymatic hydrolysis (polysaccharide lyase), (8) enzyme inactivation: mixing the high temperature reaction product and the polysaccharide lyase, and performing enzymatic hydrolysis for 4.5 hours at 33°C and pH 7.2, wherein the polysaccharide lyase: high temperature reaction product = 0.003:1 (mass ratio), after the reaction is completed, the product is inactivated at 100°C for 10 minutes, and cooled to room temperature to prepare the second enzymatic hydrolysis product. The polysaccharide lyase is composed of α-amylase, β-amylase, isoamylase, and glycosidase in a mass ratio of 1:1:1:3.

[0079] (9) Centrifugal separation, (10) Cooking to produce aroma: The second enzymatic hydrolysis product is centrifuged at 4000 rpm for 5 min, the supernatant is taken, heated to 100°C at normal pressure and maintained for 1.5 h, 10 wt% of salt is added to the supernatant to dissolve evenly, and concentrated oyster juice is prepared. The color ratio is tested to characterize the reaction intensity. If it reaches 700 or above, the flavor requirement is met.

[0080] Example 2

[0081] This embodiment is a variation of Embodiment 1, and the variation with respect to Embodiment 1 is as follows:

[0082] In the step of “(3) first stage proteolysis”, the ratio of composite protease to oyster slurry is 0.006:1 (mass ratio);

[0083] In the step of “(5) adjusting pH”, the pH value of the first enzymatic hydrolysis product is adjusted to 8.0.

[0084] The remaining steps are all referred to Example 1.

[0085] Example 3

[0086] This embodiment is a variation of Embodiment 1, and the variation with respect to Embodiment 1 is as follows:

[0087] In the step of “(3) first stage proteolysis”, the ratio of composite protease to oyster slurry was 0.003:1 (mass ratio).

[0088] The remaining steps are all referred to Example 1.

[0089] Example 4

[0090] This embodiment is a variation of Embodiment 1, and the variation with respect to Embodiment 1 is as follows:

[0091] In the step of “(3) first stage proteolysis”, the mass ratio of flavor protease, alkaline protease, papain and trypsin is 1:1:1.5:2.

[0092] The remaining steps are all referred to Example 1.

[0093] Example 5

[0094] This embodiment is a variation of Embodiment 1, and the variation with respect to Embodiment 1 is as follows:

[0095] In the step of "(7) second stage enzymatic hydrolysis", isoamylase is replaced by saccharifying enzyme.

[0096] The remaining steps are all referred to Example 1.

[0097] Example 6

[0098] This embodiment is a variation of Embodiment 1, and the variation with respect to Embodiment 1 is as follows:

[0099] In the step of "(7) second stage enzymatic hydrolysis", glycosidase is replaced by saccharifying enzyme.

[0100] The remaining steps are all referred to Example 1.

[0101] Example 7

[0102] This embodiment is a variation of Embodiment 1, and the variation with respect to Embodiment 1 is as follows:

[0103] In the step of “(7) second stage enzymatic hydrolysis”, the mass ratio of α-amylase, β-amylase, isoamylase and glycosidase is 1:1.5:0.5:1.5.

[0104] Example 8

[0105] This embodiment is a variation of Embodiment 1, and the variation with respect to Embodiment 1 is as follows:

[0106] (2) Homogenization: The oysters were shelled and impurities removed, and the oyster meat was homogenized for 5 min using a shearing machine at 4000 rpm in a ratio of oyster meat to water = 1:2 (mass ratio) to prepare oyster slurry.

[0107] (3) First stage proteolysis, (4) enzyme inactivation: adding composite protease to the oyster slurry for enzymolysis, wherein the composite protease: oyster slurry = 0.003:1 (mass ratio), enzymolysis at 55°C, pH 6.0 for 8 hours, after the reaction is completed, inactivation treatment is performed at 100°C for 10 minutes, and cooled to room temperature to prepare the first enzymolysis product. The composite protease is composed of flavor protease, alkaline protease, papain, and trypsin in a mass ratio of 1:1.5:1.2:1.2.

[0108] (5) Adjusting pH; (6) High-temperature reaction: adjusting the pH value of the first enzymatic hydrolysis product to 8.0, and keeping it at 94.5° C. for 1.5 h to prepare a high-temperature reaction product.

[0109] (7) Second stage enzymatic hydrolysis (polysaccharide lyase), (8) enzyme inactivation: mixing the high temperature reaction product and the polysaccharide lyase, and performing enzymatic hydrolysis for 4 hours at 30°C and pH 7.0, wherein the polysaccharide lyase: high temperature reaction product = 0.0025:1 (mass ratio), after the reaction is completed, inactivation treatment is performed at 100°C for 10 minutes, and cooling to room temperature to prepare the second enzymatic hydrolysis product. The polysaccharide lyase is composed of α-amylase, β-amylase, isoamylase, and glycosidase in a mass ratio of 1:0.8:1.2:3.3.

[0110] (9) Centrifugal separation, (10) Cooking to produce aroma: The second enzymatic hydrolysis product was centrifuged at 4000 rpm for 5 min, the supernatant was taken, and heated to 98°C at normal pressure for 2 h to prepare concentrated oyster juice.

[0111] Example 9

[0112] (2) Homogenization: The oysters were shelled and impurities removed, and the oyster meat was homogenized for 5 min using a shearing machine at 4000 rpm in a ratio of oyster meat to water = 1:3 (mass ratio) to prepare oyster slurry.

[0113] (3) First-stage proteolysis, (4) enzyme inactivation: adding a composite protease to the oyster slurry for enzymolysis, wherein the composite protease: oyster slurry = 0.006:1 (mass ratio), enzymolysis at 58°C, pH 6.5 for 10 hours, after the reaction is completed, inactivation treatment is performed at 100°C for 10 minutes, and cooling to room temperature to prepare a first enzymolysis product. The composite protease is composed of flavor protease, alkaline protease, papain, and trypsin in a mass ratio of 1:2.5:0.8:0.8.

[0114] (5) Adjusting pH; (6) High-temperature reaction: adjusting the pH value of the first enzymatic hydrolysis product to 8.5, and keeping it at 95.5° C. for 2.5 h to prepare a high-temperature reaction product.

[0115] (7) Second stage enzymatic hydrolysis (polysaccharide lyase), (8) enzyme inactivation: mixing the high temperature reaction product and the polysaccharide lyase, and performing enzymatic hydrolysis for 5 hours at 35°C and pH 7.5, wherein the polysaccharide lyase: high temperature reaction product = 0.0035:1 (mass ratio), after the reaction is completed, inactivation treatment is performed at 100°C for 10 minutes, and cooling to room temperature to prepare the second enzymatic hydrolysis product. The polysaccharide lyase is composed of α-amylase, β-amylase, isoamylase, and glycosidase in a mass ratio of 1:1.2:1.2:2.8.

[0116] (9) Centrifugal separation, (10) Cooking to produce aroma: The second enzymatic hydrolysis product was centrifuged at 4000 rpm for 5 min, the supernatant was taken, and heated to 102° C. at normal pressure for 2 h to prepare concentrated oyster juice.

[0117] Comparative Example 1

[0118] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0119] “(3) First stage proteolysis” and “(4) Enzyme inactivation” are omitted.

[0120] Comparative Example 2

[0121] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0122] In the step of “(5) adjusting pH”, the pH value of the first enzymatic hydrolysis product is adjusted to 7.5.

[0123] Comparative Example 3

[0124] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0125] In the step of “(5) adjusting pH”, the pH value of the first enzymatic hydrolysis product is adjusted to 6.5.

[0126] Comparative Example 4

[0127] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0128] In the step "(6) high temperature reaction", the reaction was carried out at 95°C for 1 hour.

[0129] Comparative Example 5

[0130] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0131] The step of "(6) high temperature reaction" was omitted.

[0132] Comparative Example 6

[0133] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0134] In the step of “(7) second stage enzymatic hydrolysis”, the ratio of polysaccharide lyase to high temperature reaction product is 0.0015:1 (mass ratio).

[0135] Comparative Example 7

[0136] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0137] The step “(7) second stage enzymatic hydrolysis” was omitted.

[0138] Comparative Example 8

[0139] This comparative example is a comparative example of Example 1, and the difference with respect to Example 1 is:

[0140] In the step of "(3) first stage proteolysis", flavor protease, alkaline protease, papain, and trypsin are added to the oyster slurry in sequence for enzymolysis, and the next protease is added for enzymolysis after the previous protease is hydrolyzed and inactivated. The pH value, temperature, time, and dosage of each protease hydrolysis are the same as those in Example 1.

[0141] The oyster juice prepared in each embodiment and comparative example was tested, and the test indicators included reducing sugar content, total sugar content, amino acid content and color rate. The method for determining amino nitrogen content was based on the national standard GB 5009.235-2016 Food Safety National Standard Determination of Amino Acid Nitrogen in Food. The reducing sugar method was based on the national standard GB 5009.7-2016 Food Safety National Standard Determination of Reducing Sugar in Food. The color rate was determined by spectrophotometry. The object of the test was the concentrated oyster juice in the steps of "(9) centrifugal separation and (10) cooking for aroma".

[0142] Table 1. Test data of indicators of embodiments and comparative examples

[0143]

[0144]

[0145] Alkaline protease and trypsin are alkaline proteases, flavor protease and papain are acidic proteases. Different types of multi-enzyme combination treatments and simultaneous reactions of the multi-enzyme combination form a synergistically enhanced enzymatic hydrolysis effect, which has a comprehensive effect on large molecular proteins, glycopeptides, etc. The enzymatic hydrolysis effect is better than step-by-step enzymatic hydrolysis, and the amino acid nitrogen can reach more than 0.63g / 100g.

[0146] The sensory evaluation and analysis of the oyster juices of the embodiments and comparative examples were performed, and the results are as follows:

[0147] Table 2. Sensory evaluation data of examples and comparative examples

[0148] Aroma type Example 1 Comparative Example 4 Comparative Example 7 Oyster Fragrance 4.5 3.6 2.1 Sweet 4.9 3.9 1.9 Burnt aroma 4.1 3.7 3.6 Fishy smell 1.3 1.9 3.9 Green grass fragrance 2.0 3.0 3.7

[0149] According to Table 2 and Figure 2 It can be seen that the main difference between Example 1 and Comparative Example 7 is that no polysaccharide lyase is added. From the evaluation results, the higher the reducing sugar, the better the oyster aroma and sweet aroma, and the weaker the fishy smell. The sweet aroma and oyster aroma of Example 1 are significantly better than those of Comparative Examples 4 and 7. The main reason for the analysis is that Example 1 has a high reducing sugar content. In the later Maillard reaction process, no reducing sugar is needed to generate oyster juice with richer caramel, sweet and oyster aromas and weaker fishy smell. On the whole, the preparation method of oyster juice provided by the implementation of this application adopts a segmented enzymatic hydrolysis process to prepare oyster hydrolysate. In the first stage, the protein is enzymatically hydrolyzed. By adjusting the pH value of the oyster hydrolysate and high temperature reaction, the dissolution of oyster polysaccharides is increased. In the second stage, polysaccharide degrading enzymes are used to decompose oyster polysaccharides and convert them into reducing sugars. The reducing sugar of oyster juice produced by this process reaches more than 3.4%, which is 12% higher than that of conventional oyster juice. No additional reducing sugar is needed to achieve the effect of Maillard deodorization and fragrance generation in the later stage.

[0150] The technical features of the above-mentioned implementation modes and examples can be combined in any appropriate manner. To make the description concise, not all possible combinations of the technical features in the above-mentioned implementation modes and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0151] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as a limitation on the scope of protection of the patent application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several deformations and improvements can be made, which all belong to the protection scope of the present application. In addition, it should be understood that after reading the above-mentioned teaching content of the present application, the technicians in this field can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the protection scope of the present application. It should also be understood that the technical solutions obtained by the technicians in this field through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the protection scope of the claims attached to the present application. Therefore, the protection scope of the patent of the present application shall be based on the content of the attached claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. A method for preparing oyster sauce, characterized in that: The preparation method comprises the following steps: Mix oyster meat and water, and homogenize to prepare oyster slurry; The mixture of the oyster slurry and the protease is subjected to a first stage of enzymolysis to prepare a first enzymolysis product; the protease comprises flavor protease, alkaline protease, papain and trypsin; the mass ratio of the protease to the oyster slurry is (0.003-0.006):1; Adjusting the pH value of the first enzymatic hydrolysis product to 8.0-8.5 and subjecting the product to a high temperature reaction at 94.5° C.-95.5° C. for 1.5 h-2.5 h to prepare a high temperature reaction product; The mixture of the high temperature reaction product and the polysaccharide lyase is subjected to a second stage of enzymolysis to prepare a second enzymolysis product; the mass ratio of the polysaccharide lyase to the high temperature reaction product is (0.0025-0.0035):1; and, The enzymatic hydrolysis clear liquid is separated from the second enzymatic hydrolysis product, boiled, and salt is added to prepare oyster juice.

2. The method for preparing oyster juice according to claim 1, characterized in that: The mass ratio of the flavor protease, the alkaline protease, the papain and the trypsin is 1:(1.5-2.5):(0.8-1.2):(0.8-1.2).

3. The method for preparing oyster juice according to claim 1, characterized in that: The polysaccharide lysing enzymes include α-amylase, β-amylase, isoamylase and glycosidase; Optionally, the mass ratio of α-amylase, β-amylase, isoamylase and glycosidase is 1:(0.8-1.2):(0.8-1.2):(2.8-3.3).

4. The method for preparing oyster sauce according to any one of claims 1 to 3, characterized in that: The mass ratio of the oyster meat to the water is 1:(2-3); or / and, the homogenization conditions include: a rotation speed of 3500rpm-4500rpm, and a time of 4.5min-5.5min.

5. The method for preparing oyster sauce according to any one of claims 1 to 3, characterized in that: The enzymatic hydrolysis conditions of the first stage include: temperature of 55°C-58°C, initial pH of 6.0-6.5, and time of 8h-10h.

6. The method for preparing oyster sauce according to any one of claims 1 to 3, characterized in that: The enzymatic hydrolysis conditions of the second stage include: temperature of 30°C-35°C, initial pH of 7.0-7.5, and time of 4h-5h.

7. The method for preparing oyster sauce according to any one of claims 1 to 3, characterized in that: Methods for separating the enzymatic supernatant include centrifugation; Optionally, the centrifugal conditions include: a rotation speed of 3500 rpm-4500 rpm, and a time of 4.5 min-5.5 min.

8. The method for preparing oyster sauce according to any one of claims 1 to 3, characterized in that: The cooking conditions include: normal pressure, temperature of 98° C.-102° C., and time of 1 h-2 h; or / and, the amount of salt used is 8wt%-12wt% of the enzymatic hydrolysis clear solution.

9. The method for preparing oyster sauce according to any one of claims 1 to 3, characterized in that: The preparation method further comprises the step of performing enzyme inactivation treatment after the first stage enzymolysis and / or the second stage enzymolysis are completed; Optionally, the enzyme inactivation treatment adopts a high temperature enzyme inactivation method; Further optionally, the conditions of the high temperature enzyme inactivation method include: temperature of 98°C-105°C, time of 8min-12min.

10. Oyster sauce prepared by the preparation method according to any one of claims 1 to 9.

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