Deodorization method for preparing oyster juice by using compound enzyme preparation

Abstract

The invention relates to the technical field of aquatic product processing, and particularly discloses a fishy smell removing method for preparing oyster juice by adopting a compound enzyme preparation. Lipid substances in enzymatic hydrolysate are specifically decomposed through the compound enzyme preparation, meanwhile, the enzymolysis rate of umami amino acids such as glutamic acid is increased, fishy smell precursor substances are reduced or removed, and the taste of the oyster juice is improved. The content of flavor substances such as alcohols and aldehydes in the oyster juice concentrated solution is increased, sulfur-containing heterocyclic compounds such as dimethyl trisulfide and dimethyl disulfide are remarkably reduced, the aroma coordination degree of the oyster juice is optimized, and the quality of the oyster juice product is improved; in addition, the oyster juice yield is increased by about 20% through secondary treatment of the oyster juice concentrate with the compound enzyme preparation.

Description

Technical Field

[0001] The present application relates to the technical field of aquatic product processing, and in particular to a method for removing the fishy smell of oyster juice by using a composite enzyme preparation. Background Art

[0002] Most of the existing biological deodorization methods use one or more enzyme preparations to treat seafood such as fish through an immersion liquid. For example, patent publication number CN118141064A discloses a method for deodorizing and enhancing the flavor of fish, which includes removing the head, scales, viscera and skin of a fresh fish, cutting it into fish pieces or fish fillets of uniform size and washing it with clean water; preparing a composite enzyme immersion liquid containing lipase, papain and flavor protease; mixing and encapsulating the fish pieces or fish fillets with the obtained composite enzyme immersion liquid, and performing intermittent ultrasonic treatment; and treating the obtained deodorized and flavored fish meat with a high-voltage pulse electric field to obtain deodorized and flavored fish meat. Patent publication number CN117546991A discloses a combined deodorization process for marine fish, which includes pretreatment: thawing the fish meat, cleaning it, soaking it in a soaking solution for 20-30 minutes and then rinsing it; pickling: pickling the rinsed fish meat with a pickling solution, wherein the pickling solution includes an olive fruit extract; biological deodorization treatment: cleaning the pickled fish meat and enzymatically removing the fishy smell with a biological deodorizer; post-treatment: cleaning and drying the biologically deodorized fish meat and then packaging it. Patent publication number CN117770415A discloses a method for increasing the umami flavor of oyster juice using enzymatic hydrolysis technology, using oysters and edible mushrooms crushed by a high-pressure jet mill as enzymatic substrates, using multiple enzymes to fully enzymatically hydrolyze, releasing flavor substances, and then using a deodorization and freshness enhancement reaction to remove the fishy smell of the oyster enzymatic hydrolyzate to enhance the umami flavor and obtain oyster juice.

[0003] At present, no enzyme preparations are used to remove the fishy smell in the processing of oysters or oyster juice. Most oyster juice is obtained by co-enzymatic hydrolysis of the umami substrate and then heating to obtain the umami oyster juice. In addition, the existing literature does not analyze the technology of using enzyme preparations to enhance the fishy smell after enzymatic deodorization of fishy odor precursors. Therefore, there is a lack of targeted substance treatment in the previous methods of deodorization and enhancing the fishy smell. In particular, no oyster juice with deodorization and enhanced fishy smell has been obtained by biological methods alone in the deodorization of oysters. Summary of the invention

[0004] The purpose of this application is to overcome the shortcomings of the above-mentioned prior art and provide a method for removing the fishy smell of oyster juice using a composite enzyme preparation. This application uses a new composite enzyme preparation to specifically remove the fishy smell and enhance the freshness of oyster juice, decompose the fishy smell precursors and further release umami amino acids, thereby achieving the goal of improving the quality of oyster juice.

[0005] To achieve the above purpose, the technical solution adopted by this application is:

[0006] The present application provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0007] S1, taking oysters, adding water to homogenize to obtain oyster raw material slurry, and then adding neutral protease to the oyster raw material slurry for enzymolysis to obtain enzymolysis solution;

[0008] S2, adding the complex enzyme preparation to the enzymatic hydrolyzate in step S1 and stirring to obtain a mixture, then inactivating the enzyme in the mixture, centrifuging it, and obtaining a treated enzymatic hydrolyzate clear solution;

[0009] S3, boiling the treated enzymatic hydrolysis liquid to obtain oyster juice concentrate;

[0010] Wherein, the complex enzyme preparation comprises lipase and glutaminase.

[0011] After extensive research and experiments, the inventors of the present application discovered that the present application uses a composite enzyme preparation (the composite enzyme preparation includes lipase and glutaminase) in the enzymatic hydrolysis solution to remove fishy smells. The main consideration is that more fat substances are precipitated after enzymatic hydrolysis of oysters. The production of fishy substances is mostly caused by lipid peroxidation. Therefore, the composite enzyme preparation is added after enzymatic hydrolysis to decompose the fat substances, while promoting the release of umami amino acids such as glutamic acid, thereby improving the sensory flavor of the oyster juice concentrate and thereby improving the quality of the oyster juice.

[0012] The present application uses a composite enzyme preparation to specifically decompose lipid substances in the enzymatic hydrolyzate, while increasing the enzymatic hydrolysis rate of umami amino acids such as glutamic acid, reducing or removing fishy odor precursors, and increasing the content of flavor substances such as alcohols and aldehydes in the oyster juice concentrate. Sulfur-containing heterocyclic compounds, such as dimethyl trisulfide and dimethyl disulfide, are significantly reduced, thereby optimizing the aroma coordination of oyster juice and improving the quality of oyster juice products.

[0013] As a preferred embodiment of the method for removing the fishy smell of oyster juice using a composite enzyme preparation described in the present application, the method for removing the fishy smell further comprises step S4;

[0014] S4, adding 0.1% to 0.5% of the mass of the oyster juice concentrate to the oyster juice concentrate, mixing and stirring, and then inactivating the enzyme and centrifuging to obtain an oyster juice concentrated clear solution;

[0015] The complex enzyme preparation comprises lipase and glutaminase.

[0016] The present application adopts a composite enzyme preparation for secondary treatment of oyster juice concentrate, and the obtained oyster juice concentrated clear liquid has a higher amino acid nitrogen content, and the oyster juice yield is increased by about 20%.

[0017] As a preferred embodiment of the method for removing the fishy smell of oyster juice by using a composite enzyme preparation described in the present application, in the step S1, the amount of neutral protease added is 0.5-1% of the mass of the oyster raw material slurry.

[0018] Preferably, the addition amount of the neutral protease is 0.6% of the mass of the oyster raw material slurry.

[0019] As a preferred embodiment of the method for removing the fishy smell of oyster juice by using a composite enzyme preparation described in the present application, in the step S1, the temperature of enzymatic hydrolysis is 50-55°C, and the time of enzymatic hydrolysis is 2-4 hours.

[0020] As a preferred embodiment of the method for removing the fishy smell of oyster juice by using a composite enzyme preparation described in the present application, in step S2, the addition amount of the composite enzyme preparation is 0.5-1.5% of the mass of the enzymatic hydrolyzate.

[0021] The composite enzyme preparation with the above-mentioned addition amount used in the present application can better decompose lipid substances in the enzymatic hydrolyzate, while increasing the enzymatic hydrolysis rate of umami amino acids such as glutamic acid, reducing or removing fishy odor precursors, having better sensory flavor and higher amino acid nitrogen content, thereby improving the quality of oyster juice concentrate.

[0022] As a preferred embodiment of the method for removing the fishy smell of oyster juice by using a composite enzyme preparation described in the present application, the addition amount of the composite enzyme preparation is 0.5% of the mass of the enzymatic hydrolyzate.

[0023] As a preferred embodiment of the method for removing the fishy smell of oyster juice by using a composite enzyme preparation described in the present application, the mass ratio of the lipase to the glutaminase is 1:(1-5).

[0024] The present application uses lipase to enzymatically hydrolyze the lipid components in the oyster hydrolysate, and further uses a combination of lipase and glutaminase to further release umami amino acids, thereby improving the flavor of the oyster juice.

[0025] The present application uses lipase and glutaminase in the above-mentioned mass ratio range, which can release umami amino acids to a greater extent, achieve a better effect of removing fishy smell and enhancing freshness, and thus improve the flavor of oyster juice.

[0026] As a preferred embodiment of the method for removing the fishy smell of oyster juice using a composite enzyme preparation described in the present application, the mass ratio of the lipase to the glutaminase is 1:(4-5). More preferably, the mass ratio of the lipase to the glutaminase is 1:4.

[0027] As a preferred embodiment of the method for removing the fishy smell of oyster juice by using a composite enzyme preparation described in the present application, in step S2, before inactivating the enzyme, the mixture is kept warm at a temperature of 50 to 55°C for 2 to 3 hours.

[0028] As a preferred embodiment of the method for removing the fishy smell of oyster juice using a composite enzyme preparation described in the present application, in step S1, the pH value of the oyster raw material slurry is 7;

[0029] In step S2, the pH value of the mixture is 8.

[0030] As a preferred embodiment of the method for removing the fishy smell of oyster juice by using a composite enzyme preparation described in the present application, in the step S2, the centrifugal speed is 3000-4000 r / min, and the centrifugal time is 15-20 min. Preferably, the centrifugal speed is 4000 r / min, and the centrifugal time is 20 min.

[0031] Preferably, in step S3, the cooking temperature is 105° C. and the cooking time is 3 hours.

[0032] Compared with the prior art, this application has the following beneficial effects:

[0033] The present application provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation. The present application uses the composite enzyme preparation to specifically decompose lipid substances in the enzymatic hydrolyzate, while increasing the enzymatic hydrolysis rate of umami amino acids such as glutamic acid, thereby reducing or removing fishy smell precursor substances, and increasing the content of flavor substances such as alcohols and aldehydes in the oyster juice concentrate. The content of sulfur-containing heterocyclic compounds, such as dimethyl trisulfide and dimethyl disulfide, is significantly reduced, thereby optimizing the aroma coordination of the oyster juice and improving the quality of the oyster juice product. In addition, through the secondary treatment of the oyster juice concentrate with the composite enzyme preparation, the oyster juice yield is increased by about 20%. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with specific embodiments.

[0035] In the following examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified, and the components and raw materials used in each parallel experiment are of the same type.

[0036] Example 1

[0037] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0038] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0039] 2. Compound enzyme treatment: add 0.5% compound enzyme preparation of the mass of the enzymatic hydrolysate into the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:1. Stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50℃ for 3h, then heat to 100℃ to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolysate.

[0040] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0041] Example 2

[0042] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0043] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0044] 2. Compound enzyme treatment: add 0.5% compound enzyme preparation of the mass of the enzymatic hydrolysate into the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:2. Stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50℃ for 3h, then heat to 100℃ to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolysate.

[0045] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0046] Example 3

[0047] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0048] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0049] 2. Compound enzyme treatment: add 0.5% compound enzyme preparation of the mass of the enzymatic hydrolysate to the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4. Stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50°C for 3 hours, then heat to 100°C to inactivate the enzyme for 10 minutes, and centrifuge at 4000r / min for 20 minutes to obtain the treated enzymatic hydrolysate.

[0050] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0051] Example 4

[0052] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0053] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0054] 2. Compound enzyme treatment: add 0.5% compound enzyme preparation of the mass of the enzymatic hydrolysate to the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:5, stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50-55°C for 2-3h, then heat to 100°C to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolysate.

[0055] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0056] Example 5

[0057] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0058] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0059] 2. Compound enzyme treatment: add 1% compound enzyme preparation of the mass of the enzymatic hydrolysate to the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4, stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50°C for 2h, then heat to 100°C to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolysate.

[0060] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0061] Example 6

[0062] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0063] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0064] 2. Compound enzyme treatment: add 1.5% compound enzyme preparation of the mass of the enzymatic hydrolyzate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4, stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50°C for 2h, then heat to 100°C to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolyzate.

[0065] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0066] Example 7

[0067] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0068] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0069] 2. Compound enzyme treatment: add 1% compound enzyme preparation of the mass of the enzymatic hydrolysate to the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4, stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50°C for 2h, then heat to 100°C to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolysate.

[0070] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0071] 4. Secondary treatment with complex enzyme: add 0.1% complex enzyme preparation (the complex enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4) to the oyster juice concentrate, adjust the pH to 8, keep it in a constant temperature water bath at 50°C for 2 hours, then heat it to 100°C to inactivate the enzyme for 10 minutes, and centrifuge it at 3000r / min for 10 minutes to obtain the oyster juice concentrated clear liquid.

[0072] Example 8

[0073] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0074] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0075] 2. Compound enzyme treatment: add 1% compound enzyme preparation of the mass of the enzymatic hydrolysate to the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4, stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50°C for 2h, then heat to 100°C to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolysate.

[0076] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0077] 4. Secondary treatment with complex enzyme: add 0.3% complex enzyme preparation (the complex enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4) to the oyster juice concentrate, adjust the pH to 8, keep it in a constant temperature water bath at 50-55℃ for 2h, then heat it to 100℃ to inactivate the enzyme for 10min, and centrifuge it at 3000r / min for 10min to obtain the oyster juice concentrated clear liquid.

[0078] Example 9

[0079] This embodiment provides a method for removing the fishy smell of oyster juice by using a composite enzyme preparation, comprising the following steps:

[0080] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0081] 2. Compound enzyme treatment: add 0.5% compound enzyme preparation of the mass of the enzymatic hydrolysate to the enzymatic hydrolysate, the compound enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4, stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50-55°C for 2h, then heat to 100°C to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic hydrolysate.

[0082] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0083] 4. Secondary treatment with complex enzyme: add 0.5% complex enzyme preparation (the complex enzyme preparation includes lipase and glutaminase, and the mass ratio is 1:4) to the oyster juice concentrate, adjust the pH to 8, keep it in a constant temperature water bath at 50-55℃ for 1-2h, then heat it to 100℃ to inactivate the enzyme for 10min, and centrifuge it at 3000r / min for 10min to obtain the oyster juice concentrated clear liquid.

[0084] Comparative Example 1

[0085] Comparative Example 1 provides a method for preparing oyster juice concentrate, comprising the following steps:

[0086] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0087] 2. Centrifugation: Centrifuge the enzymatic hydrolysate at 4000 r / min for 20 min to obtain the enzymatic hydrolysate.

[0088] 3. Concentration: Boil the enzymatic hydrolysis solution at 105°C for 3 hours to obtain oyster juice concentrate.

[0089] Comparative Example 2

[0090] Comparative Example 2 provides a method for preparing oyster juice concentrate, comprising the following steps:

[0091] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0092] 2. Lipase treatment: add 0.5% lipase by mass of the enzymatic hydrolysate to the enzymatic hydrolysate, stir thoroughly, adjust the pH to 8, keep in a constant temperature water bath at 50°C for 2 hours, then heat to 100°C to inactivate the enzyme for 10 minutes, and centrifuge at 4000r / min for 20 minutes to obtain the treated enzymatic hydrolysate.

[0093] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0094] Comparative Example 3

[0095] Comparative Example 3 provides a method for preparing oyster juice concentrate, comprising the following steps:

[0096] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50-55°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0097] 2. Glutamine enzyme treatment: add 0.5% glutaminase by weight of the enzymatic hydrolysate to the enzymatic hydrolysate, stir thoroughly, adjust the pH to 8, keep in a constant temperature water bath at 50°C for 2 hours, then heat to 100°C to inactivate the enzyme for 10 minutes, and centrifuge at 4000 r / min for 20 minutes to obtain the treated enzymatic hydrolysate.

[0098] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0099] Comparative Example 4

[0100] Comparative Example 4 provides a method for preparing oyster juice concentrate, comprising the following steps:

[0101] 1. Preparation of enzymatic hydrolysate: Take the thawed oysters, add distilled water according to the solid-liquid ratio of 1:2, homogenize in a wall breaking machine to obtain oyster raw material slurry, adjust the pH to 7.0, add 0.6% neutral protease by mass of the oyster raw material slurry, stir well, and enzymolyze in a constant temperature water bath at 50-55°C for 3h; take the enzymatically hydrolyzed oyster raw material slurry in a boiling water bath at 100°C for 10min to inactivate the enzyme, take out and cool to room temperature to obtain enzymatic hydrolysate.

[0102] 2. Complex enzyme treatment: add 0.5% complex enzyme preparation (complex enzyme preparation includes papain and glutaminase, and the mass ratio is 1:4) to the enzymatic solution, stir well, adjust the pH to 8, keep warm in a constant temperature water bath at 50°C for 2h, then heat to 100°C to inactivate the enzyme for 10min, and centrifuge at 4000r / min for 20min to obtain the treated enzymatic clear solution.

[0103] 3. Concentration: The treated enzymatic hydrolysis liquid is placed at 105°C and boiled for 3 hours to obtain oyster juice concentrate.

[0104] Test Example 1

[0105] The oyster juice concentrate or oyster juice concentrate clear solution obtained in Examples 1 to 9 and Comparative Examples 1 to 4 was subjected to the following measurements:

[0106] 1. Amino acid nitrogen content: detected by titrator;

[0107] 2. Sensory evaluation: Organize the evaluators to conduct sensory evaluation on the flavor of the prepared oyster sauce. Each group of evaluation requires 8 professional evaluators with professional knowledge of condiments to participate. The total sensory score is 10 points, and the higher the score, the better the flavor.

[0108] 3. Oyster juice recovery rate (%): oyster juice concentrated (clear) liquid (V / ml) / enzyme hydrolyzate (V / ml) ​​× 100%.

[0109] The results are shown in Table 1.

[0110] Table 1

[0111]

[0112] The results show that Examples 1 to 4 use different mass ratios of lipase and glutaminase to compound and treat the enzymatic hydrolyzate, which can achieve better deodorization and freshness enhancement effects. Among them, the deodorization and freshness enhancement effect is better when lipase and glutaminase are mixed in a mass ratio of 1:4.

[0113] In Examples 3, 5 and 6, different addition amounts of the composite enzyme preparation were used, and the flavor sensory score of the oyster juice was higher and the amino acid nitrogen content was also higher; among them, when the addition ratio of the composite enzyme preparation was 1% of the mass of the oyster hydrolysate, the flavor sensory score was higher and the amino acid nitrogen content was increased by 5 to 10% compared with that of Examples 3 and 6.

[0114] After the secondary treatment with the composite enzyme in Examples 7 to 9, the amino acid nitrogen content of the concentrated oyster juice obtained by centrifugation was higher, and the oyster juice yield was increased by more than 20% compared with that in Comparative Example 1.

[0115] Comparative Example 1 does not use the composite enzyme preparation for treatment, and the oyster juice has a certain sauce aroma and mellow aroma, but has a grassy and fishy smell, and the yield of oyster juice is also lower than that of the embodiments of the present application; Comparative Example 2 or Comparative Example 3 uses a single enzyme treatment, and the sensory flavor of the oyster juice is inferior to that of Examples 1 to 9.

[0116] Comparative Example 4 uses other composite enzyme combinations, but the effect of removing fishy smell and enhancing freshness is not as good as that of Examples 1 to 9, which shows that the composite enzyme preparation of the present application can better and more specifically decompose lipid substances in the enzymatic hydrolyzate, while increasing the enzymatic hydrolysis rate of umami amino acids such as glutamic acid, reducing or removing fishy smell precursors, and increasing the content of flavor substances such as alcohols and aldehydes in oyster juice concentrate, thereby optimizing the aroma coordination of oyster juice and improving the quality of oyster juice products.

[0117] Test Example 2

[0118] The volatile flavor substances of the oyster juice concentrate or oyster juice concentrate clear solution of Example 5 and Example 8 were analyzed. The results are shown in Table 2.

[0119] Table 2

[0120]

[0121]

[0122]

[0123] Among the alcohol substances, furfuryl alcohol and phenylethyl alcohol are the main components of the sauce-flavored liquor. Compared with Example 5, the relative contents of Example 8 are increased.

[0124] Among the aldehyde substances, benzaldehyde, phenylacetaldehyde, 3-methylbutanal, 2-methylbutanal, cocaaldehyde / 5-methyl-2-phenyl-2-hexenal, and 5-methylfurfural, which have caramel and nutty aromas, showed no significant changes. 3-Methylbutanal and 2-methylbutanal are generated during the Strecker degradation reaction. 3-Methylbutanal has a slightly fruity and nutty flavor; 2-methylbutanal has a sweet, slightly fruity chocolate-like flavor. Furfural is the product of the caramelization reaction of pentose. Volatile sulfur-containing compounds are key flavor compounds in many foods, mainly derived from the decomposition of sulfur-containing amino acids. Although the content is very small, their contribution to the flavor is great; Example 8 adds methylthiopropionaldehyde, which has a strong onion and meat-like aroma, and increases the aroma of oyster juice.

[0125] The threshold of nitrogen-sulfur heterocyclic compounds is generally low, and they contribute more to the flavor of oyster sauce. Pyrazines have aromas such as coffee, nuts, and meat, and furans generally have strong fragrance, sweet flavors, and caramel flavors. In addition, ethers have a pungent odor and are the main source of the fishy smell of oyster sauce.

[0126] After the oyster juice concentrate is deodorized by a composite enzyme, the key oyster juice flavor components are retained, the fishy, ​​fatty, and irritating hexanal, dimethyl trisulfide, and dimethyl disulfide are significantly reduced, and the flavor is improved.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

Claims

1. A method for removing the fishy smell of oyster juice by using a composite enzyme preparation, characterized in that: The following steps are involved: S1, taking oysters, adding water to homogenize to obtain oyster raw material slurry, and then adding neutral protease to the oyster raw material slurry for enzymolysis to obtain enzymolysis solution; S2, adding the complex enzyme preparation to the enzymatic hydrolyzate in step S1 and stirring to obtain a mixture, then inactivating the enzyme in the mixture, centrifuging it, and obtaining a treated enzymatic hydrolyzate clear solution; S3, boiling the treated enzymatic hydrolysis liquid to obtain oyster juice concentrate; Wherein, the complex enzyme preparation comprises lipase and glutaminase.

2. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 1, characterized in that: The method for removing fishy smell also includes step S4; S4, adding 0.1% to 0.5% of the mass of the oyster juice concentrate to the oyster juice concentrate, mixing and stirring, and then inactivating the enzyme and centrifuging to obtain an oyster juice concentrated clear solution; The complex enzyme preparation comprises lipase and glutaminase.

3. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 1, characterized in that: In the step S1, the amount of neutral protease added is 0.5-1% of the mass of the oyster raw material slurry.

4. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 1, characterized in that: In the step S1, the temperature of the enzymatic hydrolysis is 50-55° C., and the time of the enzymatic hydrolysis is 2-4 hours.

5. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 1, characterized in that: In the step S2, the added amount of the composite enzyme preparation is 0.5-1.5% of the mass of the enzymatic solution.

6. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 5, characterized in that: The added amount of the composite enzyme preparation is 0.5% of the mass of the enzymatic solution.

7. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 1 or 2, characterized in that: The mass ratio of the lipase to the glutaminase is 1:(1-5).

8. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 7, characterized in that: The mass ratio of the lipase to the glutaminase is 1:(4-5).

9. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 1, characterized in that: In step S2, before inactivating the enzyme, the mixture is kept at a temperature of 50 to 55° C. for 2 to 3 hours.

10. The method for removing the fishy smell of oyster juice by using a composite enzyme preparation as claimed in claim 1, characterized in that: In step S2, the centrifugal speed is 3000-4000 r / min, and the centrifugal time is 15-20 min.

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