Storage-stable oyster juice, oyster sauce and preparation method thereof

Abstract

The application discloses a storage-stable oyster juice, oyster sauce and a preparation method thereof, and relates to the technical field of food separation and extraction. The preparation of the oyster juice comprises the following steps: centrifuging the oyster juice, adding a part of oyster juice supernatant to the precipitate, adding a compound protease for enzymolysis reaction, wherein the compound protease comprises pancreatin and flavour protease, inactivating the enzyme after the enzymolysis is completed, and homogenizing and mixing the remaining oyster juice supernatant to obtain the storage-stable oyster juice. The oyster juice is subjected to segmented treatment through centrifugation, concentration, compound enzymolysis and homogenization technology, insoluble or hardly soluble macromolecular precipitates in the oyster juice are decomposed into amino acids and polypeptides, the content of umami substances in the oyster juice is increased, and the solubility of the umami substances is increased, finally, the oyster juice is subjected to homogenization and emulsification treatment with the oyster juice supernatant, the stability of the oyster juice system is increased, the shelf life quality of the oyster juice is improved, and the application product oyster sauce has more intense oyster juice flavor and rich nutritional substances.

Description

Technical Field

[0001] This invention relates to the field of food separation and extraction technology, and in particular to a storage-stable oyster juice, oyster sauce, and its preparation method. Background Technology

[0002] Oyster juice is the main raw material for oyster sauce processing. Producing high-quality oyster sauce requires extremely high-quality oyster juice. Oyster sauce made from oyster juice with uniform consistency and low turbidity has a bright color and a smooth, even texture. High turbidity in the oyster juice will result in a coarse texture, poor clarity, dullness, and poor sensory quality in the oyster sauce product. Currently, companies mainly solve the problem of oyster juice separation through stirring, but this method cannot address the issue of rapid turbidity increase during shelf life, making it difficult to meet the requirements for high-quality oyster sauce production.

[0003] Centrifugation can remove sediment from oyster juice, reducing its turbidity and improving the texture and sensory quality of oyster sauce products. However, relying solely on centrifugation to remove sediment can also lead to the loss of some flavor and nutrients in the oyster juice, reducing the utilization rate of the raw material. Therefore, there is still considerable room for improvement. Summary of the Invention

[0004] This invention provides a storage-stable oyster juice, oyster sauce, and its preparation method to solve the technical problems of rapid turbidity increase and easy stratification of oyster juice during shelf life, which affect the quality of applied products. At the same time, it improves the flavor quality of oyster sauce and reduces nutrient loss during subsequent applications.

[0005] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing stable oyster sauce, comprising the following steps:

[0006] (1) The oyster juice is centrifuged to obtain precipitate and oyster juice supernatant. The precipitate is added to the oyster juice supernatant at a mass ratio of 1:(1-2) and stirred evenly to obtain oyster juice concentrate.

[0007] (2) Add a complex protease to the oyster juice concentrate for enzymatic hydrolysis. The complex protease includes trypsin and flavor protease. After the enzymatic hydrolysis is completed, the enzyme is inactivated and then homogenized with the remaining oyster juice supernatant to obtain oyster juice that is stable for storage.

[0008] This invention utilizes centrifugation, concentration, compound enzymatic hydrolysis, and homogenization techniques to process oyster juice in stages. Centrifugation separates insoluble or poorly soluble macromolecules. A small amount of supernatant is added to concentrate the oyster juice sediment. Further, compound enzymatic hydrolysis breaks down insoluble or poorly soluble macromolecules, such as proteins, into amino acids and peptides, increasing the content and solubility of umami substances. Finally, the concentrated liquid is added back to the oyster juice supernatant and homogenized to ensure complete mixing, resulting in a highly stable oyster juice with uniform consistency and low turbidity. This maintains low turbidity throughout the shelf life and, when applied to oyster sauce products, can effectively improve sensory quality and the levels of flavor substances such as amino acids.

[0009] As a preferred embodiment, in step (2), the complex protease comprises pancreatic enzyme and flavor protease in a mass ratio of (1-2):1.

[0010] As a preferred embodiment, in step (2), the complex protease accounts for 0.3-0.5 wt% of the oyster juice concentrate.

[0011] As a preferred option, in step (2), the conditions for the enzymatic hydrolysis reaction are: enzymatic hydrolysis temperature of 30-40℃, enzymatic hydrolysis pH of 7-8, and enzymatic hydrolysis time of 2-5h.

[0012] As a preferred option, in step (2), the homogenization frequency is 1-3 kHz and the homogenization time is 5-15 min.

[0013] As a preferred option, in step (2), the enzyme inactivation treatment is carried out by keeping the solution in a boiling water bath for 15-25 minutes.

[0014] To solve the above-mentioned technical problems, the second objective of this invention is to provide a method for preparing stable oyster sauce to obtain stable oyster sauce.

[0015] To solve the above-mentioned technical problems, the third objective of this invention is to provide an oyster sauce, which uses the above-mentioned storage-stable oyster juice, comprising 40-50 wt% oyster juice, 15-20 wt% white sugar, 7-11 wt% food additives and the balance being water.

[0016] As a preferred embodiment, the food additives include 4-6 wt% modified starch, 3-4 wt% monosodium glutamate, 0.08-0.1 wt% xanthan gum, 0.3-0.4 wt% caramel color, and 0.1-0.3 wt% I+G.

[0017] To solve the above-mentioned technical problems, the fourth objective of this invention is to provide a method for preparing oyster sauce, comprising the following steps: mixing the oyster juice, white sugar, food additives and water evenly, heating to 100-105℃, and keeping warm for 20-35 minutes to obtain oyster sauce.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention addresses the issues of oyster sauce's tendency to separate and increase turbidity during shelf life. It employs centrifugation, combined enzymatic hydrolysis of the precipitate, and homogenization to break down insoluble or poorly soluble macromolecular precipitates in the oyster sauce into amino acids and peptides, increasing the content and solubility of oyster sauce's umami substances. Finally, it is homogenized and emulsified with the oyster sauce supernatant to increase the stability of the oyster sauce system, improve the shelf-life quality of the oyster sauce, and ensure that the applied oyster sauce has a richer oyster sauce flavor and abundant nutrients. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a method for preparing stable oyster juice according to an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the embodiments and comparative examples of the present invention, high-quality oyster juice is prepared by the following steps: 1 kg of oyster meat is added to 10 kg of water, boiled at 100°C for 30 minutes and then filtered. The filtrate is then added to saturated saline solution accounting for 12 wt% of its concentration, and concentrated to 1 kg to obtain oyster juice.

[0023] The following are the sources of raw materials used in the embodiments and comparative examples of this invention:

[0024] Pancreatin, purchased from Chongqing Xiang Sheng Biotechnology Co., Ltd., enzyme activity 4000U / g;

[0025] Flavor protease, purchased from Novozymes, Denmark, with an enzyme activity of 500 LAPU / g;

[0026] Papain, purchased from Guangzhou Huaqi Biotechnology Co., Ltd., with an enzyme activity of 2.0×10⁴ U / g;

[0027] Alkaline protease, purchased from Zhejiang Fuxuan Biotechnology Co., Ltd., with an enzyme activity of 2.0×10⁵ U / g.

[0028] Example 1

[0029] A method for preparing stable oyster sauce, such as Figure 1 As shown, it includes the following steps:

[0030] (1) Oyster juice pretreatment: High-quality oyster juice is separated by centrifugation to obtain precipitate and oyster juice supernatant. The precipitate is added to the oyster juice supernatant at a mass ratio of 1:1 and stirred evenly to prepare oyster juice concentrate.

[0031] (2) Add 0.5 wt% of a complex protease to the oyster juice concentrate. The complex protease includes pancreatin and flavor protease in a mass ratio of 2:1. The enzymatic hydrolysis temperature is 35℃, the enzymatic hydrolysis pH is 8.0, and the enzymatic hydrolysis time is 3h.

[0032] (3) After the enzymatic hydrolysis, the mixture was kept in a boiling water bath for 15 minutes to inactivate the enzyme. Then it was homogenized with the remaining oyster juice supernatant and homogenized for 10 minutes at a frequency of 2KHZ to obtain oyster juice that is stable for storage.

[0033] Example 2

[0034] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 1, except that in step (2), 0.3 wt% of a complex protease is added to the oyster juice concentrate.

[0035] Example 3

[0036] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 2, except that in step (2), the complex protease includes trypsin and flavor protease in a mass ratio of 1:1.

[0037] Example 4

[0038] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 3, except that in step (2), the enzymatic hydrolysis pH is 7.0.

[0039] Example 5

[0040] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 4, except that the enzymatic hydrolysis temperature in step (2) is 30°C.

[0041] Example 6

[0042] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 4, except that the enzymatic hydrolysis temperature in step (2) is 40°C.

[0043] Comparative Example 1

[0044] An oyster sauce, specifically the untreated high-quality oyster sauce of Example 1.

[0045] Comparative Example 2

[0046] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 1, except that in step (3), after the enzymatic hydrolysis is completed, the mixture is kept in a boiling water bath for 15 minutes to inactivate the enzyme, and then stirred and mixed with the remaining oyster juice supernatant to obtain stable oyster juice.

[0047] Comparative Example 3

[0048] A method for preparing stable oyster sauce includes the following steps: selecting high-quality oyster sauce, homogenizing it at a frequency of 2 kHz for 10 minutes to obtain stable oyster sauce.

[0049] Comparative Example 4

[0050] A method for preparing stable oyster juice includes the following steps: selecting high-quality oyster juice, obtaining precipitate and oyster juice supernatant by centrifugation, and collecting the oyster juice supernatant as oyster juice.

[0051] Comparative Example 5

[0052] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 1, except that in step (2), the complex protease includes papain and alkaline protease in a mass ratio of 2:1.

[0053] Comparative Example 6

[0054] A method for preparing stable oyster juice, wherein each step and the reagents and process parameters used in each step are the same as in Example 1, except that in step (2), 0.5 wt% of flavor protease is added to the oyster juice concentrate, the enzymatic hydrolysis temperature is 35°C, the enzymatic hydrolysis pH is 8.0, and the enzymatic hydrolysis time is 3h.

[0055] Application Example 1-6 and Comparative Application Example 1-6

[0056] A method for preparing oyster sauce, using the oyster juice obtained in Examples 1-6 and Comparative Examples 1-6 above, includes the following steps:

[0057] Mix 45 wt% of the above-mentioned oyster juice, 6 wt% modified starch, 20 wt% white sugar, 4 wt% monosodium glutamate, 0.1 wt% xanthan gum, 0.4 wt% caramel color, 0.2 wt% I+G and the balance water evenly, heat to 100°C and keep warm for 20 minutes to obtain the oyster sauce. The prepared oyster sauces are respectively referred to as Application Examples 1-6 and Comparative Application Examples 1-6.

[0058] Performance testing

[0059] 1. Turbidity Comparison Analysis of Oyster Juice Shelf Life: After the oyster juice of the examples and comparative examples was filled and sealed, the turbidity of the oyster juice prepared in the examples and comparative examples was tested at 0d, 7d, 15d, 30d and 45d respectively according to the standard GB / T13200-1991. The storage environment temperature was 20℃ and the humidity was 60%. The test results are shown in Table 1 below.

[0060] Table 1 - Results of turbidity test of oyster sauce during shelf life for the examples and comparative examples

[0061]

[0062] Based on the turbidity results shown in Table 1, Example 1 showed the slowest rate of turbidity increase, while Comparative Example 1 showed the fastest rate of turbidity increase. After 45 days of storage, the turbidity increase in Example 1 was 469 NTU less than that in Comparative Example 1, indicating that the method of this application helps to suppress the rate of turbidity increase during the shelf life of oyster sauce and improve the shelf-life stability of oyster sauce.

[0063] Meanwhile, the turbidity increase rate of Comparative Examples 3 and 2 was lower than that of Comparative Example 1, indicating that both enzymatic hydrolysis and homogenization treatment helped to appropriately reduce the turbidity of oyster juice, but the reduction was not as significant as that of Example 1; the turbidity of Comparative Example 5 increased faster than that of Example 1, indicating that the binding effect of trypsin and flavor protease in this application is significantly better than that of papain and alkaline protease.

[0064] 2. Analysis of total nitrogen, amino acid nitrogen, degree of hydrolysis and protein recovery rate of oyster juice: The amino acid nitrogen content of the oyster juice prepared in the examples and comparative examples was determined according to the standard GB 5009.235-2016, and the degree of hydrolysis and protein recovery rate were also determined. The results are shown in Table 2 below.

[0065] The method for determining the degree of hydrolysis is as follows: The total amount of oyster juice and the free ammonia nitrogen content of the supernatant after centrifugation are measured separately. The free ammonia nitrogen content is determined using formaldehyde potentiometric titration. The formula for calculating the degree of hydrolysis is:

[0066]

[0067] The protein recovery rate was determined as follows: the total amount of oyster juice and the protein content of the supernatant after centrifugation were measured separately. The protein content was determined according to the standard GB 5009.5-2010. The formula for calculating the protein recovery rate is as follows:

[0068]

[0069] Table 2 - Test results of total nitrogen, amino acid nitrogen, degree of hydrolysis and protein recovery rate of oyster sauce

[0070]

[0071] As shown in Table 2, Examples 1-6 verified the effects of different enzymatic hydrolysis conditions on oyster juice, such as the amount of compound protease added, the ratio of compound protease, the hydrolysis pH, and the hydrolysis temperature. The optimal enzymatic hydrolysis parameters were preliminarily determined to be: a compound protease concentration of 0.5%, a trypsin to flavor protease mass ratio of 2:1, a hydrolysis pH of 8.0, and a hydrolysis temperature of 35°C. Meanwhile, Example 1 showed significant improvements in all indicators compared to Comparative Examples 1 and 3, with the degree of hydrolysis of oyster juice increasing by at least 6.39% and the protein recovery rate increasing by at least 5.56%. This indicates that enzymatic hydrolysis helps to enhance the protein and umami substances in oyster juice and improve its quality.

[0072] 3. Sensory evaluation of oyster sauce: Sensory evaluation was conducted on the oyster sauce prepared for the corresponding use case and the comparative application case. Ten professional tasters were organized to conduct sensory evaluation of the oyster sauce. The evaluation criteria are shown in Table 3 below. A sensory score of 80 or above indicates that the oyster sauce has a good sensory flavor. The evaluation score is calculated as the average score of the 10 tasters. The evaluation results are shown in Table 4 below.

[0073] Table 3 - Sensory Evaluation Criteria for Oyster Sauce

[0074]

[0075] Table 4 - Sensory evaluation results of oyster sauce in application examples and comparative application examples

[0076]

[0077]

[0078] According to the sensory evaluation results of oyster sauce in Table 4, the oyster sauce prepared by centrifugation, enzymatic hydrolysis of the precipitate, and homogenization in Application Example 1 has a higher sensory evaluation result. In contrast, the oyster sauce prepared by Application Examples 1 and 3, which did not undergo enzymatic hydrolysis, lacked flavor. In contrast, the oyster sauce prepared by Application Example 2, which did not undergo homogenization, was unevenly mixed, resulting in a strong grainy texture, an uneven consistency, and layered color. Compared to Application Examples 1-3, the sensory evaluation result was at least 13.4 higher. This indicates that enzymatic hydrolysis of the precipitate is beneficial to improving the quality of the oyster sauce, resulting in a rich oyster aroma, harmonious fragrance, thick taste, sweet and delicious flavor, and a uniform and smooth consistency. The oyster sauce prepared by this method has the best quality.

[0079] 4. Amino acid analysis of oyster sauce: The amino acid analysis of oyster sauce prepared according to the corresponding use cases and comparative application examples of the standard GB / T 5009.124-2016 was performed, and the test results are shown in Table 5 below.

[0080] Table 5 - Amino acid test results of oyster sauce in application examples and comparative application examples

[0081]

[0082]

[0083] According to the amino acid test results in Table 5, the total amino acid content of Application Example 1 was higher than that of Comparative Application Example 1 and Comparative Application Example 3. The total amino acid content of Application Example 1 was increased by about 2.7% compared with Comparative Application Example 1, indicating that enzymatic hydrolysis helps to increase the content of flavor substances in oyster juice and improve the application effect of the product.

[0084] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for preparing stable oyster sauce, characterized in that, Includes the following steps: (1) The oyster juice is centrifuged to obtain precipitate and oyster juice supernatant. The precipitate is added to the oyster juice supernatant at a mass ratio of 1:(1-2) and stirred evenly to obtain oyster juice concentrate. (2) Add a complex protease to the oyster juice concentrate for enzymatic hydrolysis. The complex protease includes trypsin and flavor protease. After the enzymatic hydrolysis is completed, the enzyme is inactivated and then homogenized with the remaining oyster juice supernatant to obtain oyster juice that is stable for storage. In step (1), the oyster juice is prepared by the following steps: 1 kg of oyster meat is added to 10 kg of water, boiled at 100°C for 30 min and then filtered. The filtrate is then added to 12 wt% of saturated brine and concentrated to 1 kg to obtain the oyster juice. In step (2), the complex protease comprises a pancreatic enzyme and a flavor protease in a mass ratio of (1-2):1; In step (2), the complex protease accounts for 0.3-0.5 wt% of the oyster juice concentrate. In step (2), the conditions for the enzymatic hydrolysis reaction are: enzymatic hydrolysis temperature 30-40℃, enzymatic hydrolysis pH 7-8, and enzymatic hydrolysis time 2-5h; In step (2), the homogenization frequency is 1-3 kHz and the homogenization time is 5-15 min.

2. The method for preparing a storage-stable oyster sauce as described in claim 1, characterized in that, In step (2), the enzyme inactivation treatment is carried out by incubating in a boiling water bath for 15-25 minutes.

3. A method for preparing storage-stable oyster sauce as described in claim 1 or 2.

4. An oyster sauce, characterized in that, The oyster sauce with stable storage as described in claim 3 is characterized by comprising 40-50 wt% oyster sauce, 15-20 wt% white sugar, 7-11 wt% food additives, and the balance being water.

5. The oyster sauce as described in claim 4, characterized in that, The food additives include 4-6 wt% modified starch, 3-4 wt% monosodium glutamate, 0.08-0.1 wt% xanthan gum, 0.3-0.4 wt% caramel color, and 0.1-0.3 wt% I+G, accounting for 4-6 wt% of the total oyster sauce.

6. A method for preparing oyster sauce as described in claim 4 or 5, characterized in that, Includes the following steps: After mixing the oyster juice, white sugar, food additives and water evenly, heat to 100-105℃ and keep warm for 20-35 minutes to obtain oyster sauce.

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