Moisture-resistant yeast extract and preparation method thereof

Abstract

This application relates to a hygroscopic yeast extract and its preparation method. The preparation method comprises the following steps: preparing yeast cell walls into a yeast cell wall suspension; adding active yeast to the yeast cell wall suspension to autolyze the yeast cell wall with endogenous enzymes to produce an autolysis product; adding papain, aminopeptidase, and flavor neutral protease to the autolysis product to hydrolyze the product with exogenous enzymes to produce an enzymatic hydrolysis product; and separating the hydrolysis supernatant from the enzymatic hydrolysis product to produce a hygroscopic yeast extract. This method achieves deep hydrolysis of the yeast cell walls, and the resulting yeast extract not only has a good, rich flavor but also exhibits excellent hygroscopic resistance.

Description

Technical Field

[0001] The present application relates to the technical field of yeast and yeast extract preparation, and in particular to a moisture-absorbing resistant yeast extract and a preparation method thereof. Background Art

[0002] Yeast extract has a prominent umami and rich flavor, and meets the public's demand for healthy and natural foods. It has a large market demand and great potential for future development. However, the powdered yeast extracts currently available on the market generally have the technical defect of being easily absorbing moisture. After absorbing water, the yeast extracts are easily deliquesced, making the product itself difficult to preserve. Subsequent processed products are also prone to deliquesce and deteriorate, which greatly affects the further use of yeast extracts in seasonings and foods. For example, instant flour packets, chicken essence, chicken powder, pork rib powder, snack food toppings, and savory flavorings often add a certain amount of yeast extract to enhance the flavor. However, due to the hygroscopicity of the yeast extract raw material, it is difficult to use in environments with high humidity, affecting the ease of seasoning processing and having a certain adverse effect on the finished product properties of the prepared powdered compound seasoning.

[0003] Currently, there are few yeast extracts in the industry that are resistant to moisture absorption. Although some manufacturers claim that their yeast extract products have certain moisture absorption resistance and can be placed at 37°C and 70% humidity for one hour without hygroscopic deliquesce, they have not disclosed specific technical means to improve the moisture absorption problem.

[0004] A domestic patent application describes a method for preparing yeast extract. This method uses a non-polar porous resin as an adsorption carrier to treat enzymatic hydrolysis products. This method exploits the varying adsorption capacities of the non-polar porous resin for substances of varying polarity, combined with an ethanol solution as a special desorbent, to achieve effective and selective separation of polar sugars, the primary components of the enzymatic hydrolysis products that are prone to deliquescence. After separation with the non-polar resin, the resulting yeast extract exhibits significantly improved moisture absorption resistance. However, this method is complex, and the use of resin adsorption significantly reduces yeast extract yield, significantly increasing manufacturing costs. Summary of the Invention

[0005] Based on this, it is necessary to provide a moisture-resistant yeast extract and a preparation method thereof that can improve moisture-resistant performance and has a simple process.

[0006] One embodiment of the present application provides a method for preparing a moisture-resistant yeast extract, comprising the following steps:

[0007] preparing yeast cell walls into a yeast cell wall suspension;

[0008] adding active yeast to the yeast cell wall suspension to autolyze endogenous enzymes to prepare an autolysis product;

[0009] adding papain, aminopeptidase and flavor neutral protease to the autolyzed product to perform enzymatic hydrolysis with exogenous enzymes to prepare an enzymatic hydrolysis product; and

[0010] The enzymatic supernatant is separated from the enzymatic hydrolysis product to prepare a moisture absorption resistant yeast extract.

[0011] In one embodiment, the preparation of yeast cell wall comprises the following steps:

[0012] Heating and keeping the yeast suspension warm; and,

[0013] The treated yeast suspension is subjected to solid-liquid separation, the solid phase is collected, and the yeast cell wall is prepared.

[0014] In one embodiment, the yeast concentration in the yeast suspension is 100 g / L to 150 g / L.

[0015] In one embodiment, the step of heating and heat-insulating the yeast suspension comprises:

[0016] The yeast suspension is heated to a temperature of 90° C. to 95° C. and kept warm for 2 h to 5 h.

[0017] In one embodiment, the yeast cell wall concentration in the yeast cell wall suspension is 100 g / L to 150 g / L.

[0018] In one embodiment, the amount of active yeast added is 0.5% to 2% of the dry weight of the yeast cell wall.

[0019] In one embodiment, the temperature for autolysis of the endogenous enzyme is 45°C to 60°C.

[0020] In one embodiment, the autolysis time of the endogenous enzyme is 4 hours to 8 hours.

[0021] In one embodiment, the amount of papain added is 0.01% to 0.5% of the dry weight of the yeast cell wall.

[0022] In one embodiment, the aminopeptidase is added in an amount of 0.01% to 0.5% of the dry weight of the yeast cell wall.

[0023] In one embodiment, the amount of the flavored egg white enzyme added is 0.01% to 0.5% of the dry weight of the yeast cell wall.

[0024] In one embodiment, the temperature of the exogenous enzyme hydrolysis is 50°C to 65°C.

[0025] In one embodiment, the enzymatic hydrolysis time of the exogenous enzyme is 16 hours to 20 hours.

[0026] In one embodiment, the following steps are also included:

[0027] The enzymatic hydrolysis supernatant is evaporated, concentrated and spray-dried.

[0028] In one embodiment, the temperature of evaporation concentration is 50°C to 80°C.

[0029] In one embodiment, the solid content of the product obtained after evaporation and concentration is 30% to 35%.

[0030] In one embodiment, the inlet air temperature of the spray drying is 150°C to 200°C, and the outlet air temperature is 95°C to 105°C.

[0031] An embodiment of the present application further provides a moisture-resistant yeast extract, which is prepared by the method described in any of the above embodiments.

[0032] The preparation method provided in the present application uses yeast cell walls as raw materials, firstly adds active yeast to achieve autolysis using endogenous enzymes, and then adds a combined exogenous enzyme preparation composed of papain, aminopeptidase, and flavor neutral protease for enzymatic hydrolysis. The combination of endogenous enzyme autolysis and exogenous enzyme hydrolysis achieves deep hydrolysis of the yeast cell walls. The prepared yeast extract not only has a good and rich flavor, but also contains less hygroscopic substances such as small molecule sugars, amino acids, and nucleic acids than unisolated yeast. The yeast cell walls used in the present application are used as raw materials, and the content of hygroscopic substances such as small molecule sugars, amino acids, and nucleic acids is reduced. The combination of endogenous enzyme autolysis and exogenous enzyme hydrolysis controls the degree of enzymatic hydrolysis, further reducing the content of hygroscopic substances in the hydrolysis product, making the final product have excellent moisture absorption resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a comparison chart of the yeast extracts prepared in Example 3 and Comparative Example 1 after being left open in an environment of 25° C. and 50% humidity for 1 hour. DETAILED DESCRIPTION

[0034] To facilitate understanding of the present application, the present application will be described more fully below in conjunction with the embodiments and accompanying drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended solely for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] In this 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.

[0037] One embodiment of the present application provides a method for preparing a moisture-resistant yeast extract, comprising the following steps:

[0038] preparing yeast cell walls into a yeast cell wall suspension;

[0039] Active yeast is added to the yeast cell wall suspension to perform autolysis by endogenous enzymes to prepare an autolysis product;

[0040] adding papain, aminopeptidase and flavor neutral protease to the autolyzed product to perform enzymatic hydrolysis with exogenous enzymes to prepare an enzymatic hydrolysis product; and

[0041] The enzymatic supernatant is separated from the enzymatic hydrolysis product to prepare the moisture absorption resistant yeast extract.

[0042] The preparation method provided by the present application uses yeast cell wall as raw material, first adds active yeast for autolysis, and then adds papain, aminopeptidase and flavor neutral protease for further enzymatic hydrolysis, wherein the active yeast contains rich yeast endogenous enzymes, which can promote the autolysis and enzymatic hydrolysis of the yeast cell wall, papain is an endoprotease, which can cut large molecular proteins into small peptides, the active ingredient of aminopeptidase is mainly an exoprotease, which can enzymatically hydrolyze peptides into free amino acids, and the flavor neutral protease has both endoenzyme and exoenzyme activities. The combination of the above-mentioned combined enzymatic hydrolysis technology takes into account the activity and function of yeast endogenous enzymes, exogenous endoenzymes and exoenzymes, and can It can achieve deep hydrolysis of yeast cell walls, fully decompose proteins into small molecules, greatly improve the utilization rate of proteins in the cell walls, and strengthen the production of free amino acids, so that the prepared yeast extract not only has a good and rich flavor, but also, compared with the traditional technology of directly using yeast as the raw material to prepare the extract, the small molecular sugars, amino acids, nucleic acids and other hygroscopic substances in the yeast cells have been dissolved, and the separated yeast cell walls contain less hygroscopic substances. In combination with specific enzymatic hydrolysis technology and controlled enzymatic hydrolysis degree, the prepared yeast extract has good moisture absorption resistance.

[0043] It is understandable that, in the present application, there is no particular limitation on the source of yeast cell walls, which should be understood to be within the scope of protection of the present application.

[0044] In one embodiment, the preparation of yeast cell walls comprises the following steps:

[0045] Heating and keeping the yeast suspension warm; and,

[0046] The treated yeast suspension is subjected to solid-liquid separation, the solid phase is collected, and yeast cell walls are prepared.

[0047] The yeast cell walls prepared by the above method typically have a protein content of ≥55%. During the heat inactivation process, small molecule sugars, amino acids, and nucleic acids within the yeast cells are dissolved and released into the solution. After separation, the solid yeast cell walls are used as a raw material to further prepare a yeast extract. Compared to the supernatant, the resulting product contains less hygroscopic components such as small molecule sugars, amino acids, and nucleic acids, and has better moisture absorption resistance. Furthermore, in conventional techniques, after separating the yeast suspension, the supernatant is usually collected to prepare a high-nucleotide yeast extract. The yeast cell walls in the solid phase are rarely utilized, usually existing only as a byproduct with a low utilization rate. This application utilizes the yeast cell walls as a raw material for a moisture-resistant product, achieving high-value utilization of the byproduct. Furthermore, the yeast cell walls prepared by the above heat extraction method contain a significantly higher protein content than the cell walls separated after yeast autolysis and enzymatic hydrolysis, making it more conducive to the preparation of a yeast extract with good flavor and outstanding moisture absorption resistance.

[0048] It is understandable that the yeast used in this application can be purchased from outside or obtained through self-culture.

[0049] Furthermore, the yeast concentration in the yeast suspension is 100 g / L to 150 g / L. Within this concentration range, the yeast suspension has an appropriate viscosity and is more suitable for subsequent processing. It is understood that the yeast concentration in the yeast suspension can be, for example, but not limited to, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, and the like.

[0050] Furthermore, the step of heating and holding the yeast suspension includes heating the yeast suspension to a temperature of 90°C to 95°C and holding the temperature for 2 to 5 hours. This temperature range allows for complete yeast inactivation and sufficient dissolution and separation of substances within the yeast cell walls. For example, the temperature can be, but is not limited to, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, etc., and the holding time can be, but is not limited to, 2 hours, 3 hours, 4 hours, 5 hours, etc.

[0051] In one embodiment, the yeast cell wall concentration in the yeast cell wall suspension is 100 g / L to 150 g / L. Within this concentration range, a suitable enzymatic environment is provided for subsequent autolysis and exogenous enzymatic hydrolysis of the cell walls, thereby improving enzymatic hydrolysis efficiency, reducing process time, and increasing equipment utilization. It is understood that the yeast cell wall concentration in the yeast cell wall suspension can be, for example, but not limited to, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, and so on.

[0052] In one embodiment, the amount of active yeast added is 0.5% to 2% of the dry weight of the yeast cell walls. Active yeast is rich in endogenous yeast enzymes. Adding an appropriate amount of active yeast can compensate for the inactivation of endogenous enzymes caused by yeast inactivation during the yeast cell wall preparation process, thereby improving the efficiency of autolysis and enzymatic hydrolysis. It is understood that the amount of active yeast added can be, but is not limited to, 0.5%, 1%, 1.5%, 2%, etc., of the dry weight of the yeast cell walls.

[0053] In one embodiment, the temperature for autolysis of the endogenous enzyme is 45°C to 60°C. Within this temperature range, the endogenous enzymes in the active yeast have good enzymatic activity and can fully function. It is understood that the temperature for autolysis of the endogenous enzyme can be, but is not limited to, 45°C, 48°C, 50°C, 52°C, 55°C, 57°C, 60°C, etc.

[0054] In one embodiment, the autolysis time of the endogenous enzyme is 4 to 8 hours. Controlling the appropriate autolysis time can achieve sufficient autolysis of the yeast cell wall and help control equipment energy consumption and utilize it rationally. It is understood that the autolysis time of the endogenous enzyme can be, but is not limited to, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc.

[0055] In one embodiment, the amount of papain added is 0.01% to 0.5% of the dry weight of the yeast cell wall. The appropriate amount of papain added can fully hydrolyze the protein in the yeast cell wall into short peptides. It is understood that the amount of papain added can be, for example, but not limited to, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc. of the dry weight of the yeast cell wall.

[0056] In one embodiment, the amount of aminopeptidase added is 0.01% to 0.5% of the dry weight of the yeast cell wall. An appropriate amount of aminopeptidase added can promote the further hydrolysis of small peptide chains into free amino acids. It is understood that the amount of aminopeptidase added can be, for example, but not limited to, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc., of the dry weight of the yeast cell wall.

[0057] In one embodiment, the flavor neutral protease is added in an amount of 0.01% to 0.5% of the dry weight of the yeast cell walls. A suitable combination of flavor neutral protease with aminopeptidase and papain can provide sufficient endo- and exo-proteases to fully promote the hydrolysis of small peptide chains into free amino acids. It is understood that the amount of flavor neutral protease added can be, but is not limited to, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc., of the dry weight of the yeast cell walls.

[0058] In one embodiment, the temperature of the exogenous enzyme hydrolysis is 50°C to 65°C. A suitable hydrolysis temperature can enable papain, aminopeptidase, and flavor neutral protease to have relatively suitable enzymatic activities, which is conducive to improving the efficiency of the exogenous enzyme hydrolysis. It is understood that the temperature of the exogenous enzyme hydrolysis can be, but is not limited to, 50°C, 53°C, 55°C, 58°C, 60°C, 62°C, 65°C, etc.

[0059] In one embodiment, the exogenous enzyme hydrolysis time is 16 hours to 20 hours. An appropriate enzymatic hydrolysis time can ensure sufficient enzymatic hydrolysis, allowing the protein to be fully hydrolyzed into small amino acids, while also avoiding risks such as microbial contamination of the hydrolyzate and low equipment utilization caused by the enzymatic hydrolysis time. It is understood that the exogenous enzyme hydrolysis time can be, but is not limited to, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, etc.

[0060] In one embodiment, after the exogenous enzyme hydrolysis is completed, an enzyme inactivation step is further included. The enzyme inactivation conditions include: a temperature of 80°C to 90°C for 25 minutes to 35 minutes. Preferably, the enzyme inactivation conditions include: a temperature of 85°C for 30 minutes.

[0061] In one embodiment, the method further comprises the steps of: evaporating and concentrating the enzymatic hydrolysis supernatant and spray drying the enzymatic hydrolysis supernatant. The combination of evaporating and concentrating and spray drying can fully dry the enzymatic hydrolysis supernatant, resulting in a product with low water content.

[0062] Furthermore, the evaporation and concentration temperature is 50°C to 80°C. Within this temperature range, the evaporation and concentration efficiency is high and can effectively avoid the product from being burnt due to excessively high temperatures. It is understood that the evaporation and concentration temperature can be, for example, but not limited to, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.

[0063] Furthermore, the solid content of the product obtained after evaporation and concentration is 30% to 35%. Evaporation and concentration to a high concentration as much as possible facilitates faster completion of the subsequent spray drying process and helps save energy. It is understood that the solid content of the product obtained after evaporation and concentration can be, for example, but not limited to, 30%, 31%, 32%, 33%, 34%, 35%, etc.

[0064] Furthermore, the inlet air temperature of the spray drying is 150°C to 200°C, and the outlet air temperature is 95°C to 105°C. Appropriate inlet and outlet air temperatures can help improve drying efficiency, make drying more thorough, reduce product moisture content, and minimize the impact of the drying process on the flavor of the product, avoiding a burnt feeling. It is understandable that the inlet air temperature can be, but is not limited to, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C, and the outlet air temperature can be, but is not limited to, 95°C, 100°C, or 105°C, etc.

[0065] An embodiment of the present application further provides a moisture-resistant yeast extract, which is prepared by the method of any of the above embodiments.

[0066] The following specific examples further illustrate the moisture-resistant yeast extract and its preparation method of the present application. While the following examples are relatively specific, it is understood that other examples are not limited thereto. Unless otherwise specified, the instruments, reagents, and materials used in the following specific examples are all conventional instruments, reagents, and materials available in the prior art and can be obtained through reputable commercial channels. The experimental methods and detection methods used in the following examples are all conventional experimental methods and detection methods available in the prior art, unless otherwise specified.

[0067] Active yeast, commercially available, specifications are low-sugar active dry yeast, yeast viability ≥ 75%.

[0068] Papain is commercially available with a specification of 500,000 U / g.

[0069] Aminopeptidase, commercially available, with a specification of 60,000 U / g.

[0070] Flavor neutral protease, commercially available, specification is 150,000 U / g.

[0071] Example 1

[0072] The preparation of yeast extract includes the following steps:

[0073] 1. Prepare yeast suspension with a concentration of 100 g / L. Heat the yeast suspension to 90°C and keep it warm for 5 hours.

[0074] 2. After heating, cool the yeast suspension to 60°C and centrifuge to collect the solid phase to prepare yeast cell walls;

[0075] 3. The yeast cell walls prepared in step (2) are prepared into a yeast cell wall suspension with a concentration of 150 g / L;

[0076] 4. Add active yeast at a rate of 0.5% of the dry weight of yeast cell walls to the yeast cell wall suspension prepared in step (3), and autolyze at 45° C. for 8 h to prepare an autolyzed product;

[0077] 5. Add papain, aminopeptidase, and flavor neutral protease to the autolyzed product prepared in step (4), wherein the addition amounts of papain, aminopeptidase, and flavor neutral protease are 0.5%, 0.5%, and 0.5% of the dry weight of the yeast cell wall, respectively. Perform enzymolysis at 65° C. for 20 h. After the enzymolysis is completed, treat at 85° C. for 30 min to inactivate the enzymes to prepare an enzymolysis product.

[0078] 6. After the enzymatic hydrolysis product prepared in step (5) is cooled to 60° C., it is centrifuged and the enzymatic hydrolysis supernatant is collected;

[0079] 7. The enzymatic supernatant collected in step (6) was subjected to vacuum evaporation and concentration at 80° C. until the solid content was 35%;

[0080] 8. The product after evaporation and concentration in step (7) was spray-dried using a spray dryer to obtain a powdered yeast extract. The inlet air temperature of the spray dryer was 150° C. and the outlet air temperature was 95° C.

[0081] Example 2

[0082] The preparation of yeast extract includes the following steps:

[0083] 1. Prepare yeast suspension with a concentration of 150g / L. Heat the yeast suspension to 95°C and let it stand for 2 hours.

[0084] 2. After heating, cool the yeast suspension to 60°C and centrifuge to collect the solid phase to prepare yeast cell walls;

[0085] 3. The yeast cell wall prepared in step (2) was prepared into a yeast cell wall suspension with a concentration of 100 g / L;

[0086] 4. Add active yeast at a rate of 2% of the dry weight of yeast cell walls to the yeast cell wall suspension prepared in step (3), and autolyze at 60° C. for 4 h to prepare an autolyzed product;

[0087] 5. Add papain, aminopeptidase, and flavor neutral protease to the autolyzed product prepared in step (4), wherein the addition amounts of papain, aminopeptidase, and flavor neutral protease are 0.05%, 0.05%, and 0.05% of the dry weight of the yeast cell wall, respectively. Perform enzymolysis at 50° C. for 16 h. After the enzymolysis is completed, treat at 85° C. for 30 min to inactivate the enzymes to prepare an enzymolysis product.

[0088] 6. After the enzymatic hydrolysis product prepared in step (5) is cooled to 60° C., it is centrifuged and the enzymatic hydrolysis supernatant is collected;

[0089] 7. The enzymatic supernatant collected in step (6) was subjected to vacuum evaporation and concentration at 50° C. until the solid content was 30%;

[0090] 8. The product after evaporation and concentration in step (7) was spray-dried using a spray dryer to obtain a powdered yeast extract. The inlet air temperature of the spray dryer was 200°C and the outlet air temperature was 105°C.

[0091] Example 3

[0092] The preparation of yeast extract includes the following steps:

[0093] 1. Prepare yeast suspension with a concentration of 130g / L. Heat the yeast suspension to 93°C and let it stand for 3 hours.

[0094] 2. After heating, cool the yeast suspension to 60°C and centrifuge to collect the solid phase to prepare yeast cell walls;

[0095] 3. The yeast cell walls prepared in step (2) were prepared into a yeast cell wall suspension with a concentration of 130 g / L;

[0096] 4. Add active yeast at 1% of the dry weight of yeast cell walls to the yeast cell wall suspension prepared in step (3), and autolyze at 55° C. for 6 h to prepare an autolyzed product;

[0097] 5. Add papain, aminopeptidase, and flavor neutral protease to the autolyzed product prepared in step (4), wherein the addition amounts of papain, aminopeptidase, and flavor neutral protease are 0.2%, 0.2%, and 0.1% of the dry weight of the yeast cell wall, respectively. Enzyme hydrolysis is carried out at 55° C. for 18 h. After the enzymatic hydrolysis, the enzyme is inactivated at 85° C. for 30 min to prepare an enzymatic hydrolysis product.

[0098] 6. After the enzymatic hydrolysis product prepared in step (5) is cooled to 60° C., it is centrifuged and the enzymatic hydrolysis supernatant is collected;

[0099] 7. The enzymatic supernatant collected in step (6) was subjected to vacuum evaporation and concentration at 65°C until the solid content was 33%;

[0100] 8. The product after evaporation and concentration in step (7) was spray-dried using a spray dryer to obtain a powdered yeast extract. The inlet air temperature of the spray dryer was 180° C., and the outlet air temperature was 100° C.

[0101] Comparative Example 1

[0102] The preparation of yeast extract includes the following steps:

[0103] 1. Prepare yeast suspension with a concentration of 130g / L. Heat the yeast suspension to 93°C and let it stand for 3 hours.

[0104] 2. After heating is completed and the temperature is lowered to 55°C, active yeast is added to the yeast suspension prepared in step (1) at a rate of 1% of the dry weight of the yeast, and the mixture is autolyzed at 55°C for 6 hours to prepare an autolyzed product;

[0105] 3. Add papain, aminopeptidase and flavor neutral protease to the autolyzed product after the treatment in step (2), wherein the addition amounts of papain, aminopeptidase and flavor neutral protease are 0.2%, 0.2% and 0.1% of the dry weight of the yeast, respectively, and perform enzymolysis at 55° C. for 18 h. After the enzymolysis is completed, treat at 85° C. for 30 min to inactivate the enzymes to prepare an enzymolysis product;

[0106] 4. After the enzymatic hydrolysis product prepared in step (3) is cooled to 60°C, it is centrifuged and the enzymatic hydrolysis supernatant is collected;

[0107] 5. The enzymatic supernatant collected in step (4) was subjected to vacuum evaporation and concentration at 65°C until the solid content was 33%;

[0108] 6. The product after evaporation and concentration in step (5) was spray-dried using a spray dryer to obtain a powdered yeast extract. The inlet air temperature of the spray dryer was 180° C. and the outlet air temperature was 100° C.

[0109] Comparative Example 2

[0110] The preparation of yeast extract includes the following steps:

[0111] 1. Prepare yeast suspension with a concentration of 130g / L. Heat the yeast suspension to 93°C and let it stand for 3 hours.

[0112] 2. After heating, cool the yeast suspension to 60°C and centrifuge to collect the solid phase to prepare yeast cell walls;

[0113] 3. The yeast cell walls prepared in step (2) were prepared into a yeast cell wall suspension with a concentration of 130 g / L;

[0114] 4. Add papain, aminopeptidase, and flavor neutral protease to the yeast cell wall suspension prepared in step (3), wherein the addition amounts of papain, aminopeptidase, and flavor neutral protease are 0.2%, 0.2%, and 0.1% of the dry weight of the yeast cell wall, respectively. Enzyme hydrolysis is carried out at 55° C. for 18 h. After the enzymatic hydrolysis, the enzyme is inactivated at 85° C. for 30 min to prepare an enzymatic hydrolysis product.

[0115] 5. After the enzymatic hydrolysis product prepared in step (4) is cooled to 60°C, it is centrifuged and the enzymatic hydrolysis supernatant is collected;

[0116] 6. The supernatant collected in step (5) was concentrated by vacuum evaporation at 65°C until the solid content was 33%;

[0117] 7. The product after evaporation and concentration in step (6) was spray-dried using a spray dryer to obtain a powdered yeast extract. The inlet air temperature of the spray dryer was 180° C. and the outlet air temperature was 100° C.

[0118] Comparative Example 3

[0119] The preparation of yeast extract includes the following steps:

[0120] 1. Prepare yeast suspension with a concentration of 130g / L. Heat the yeast suspension to 93°C and let it stand for 3 hours.

[0121] 2. After heating, cool the yeast suspension to 60°C and centrifuge to collect the solid phase to prepare yeast cell walls;

[0122] 3. The yeast cell walls prepared in step (2) were prepared into a yeast cell wall suspension with a concentration of 130 g / L;

[0123] 4. Add active yeast at 1% of the dry weight of yeast cell walls to the yeast cell wall suspension prepared in step (3), and autolyze at 55° C. for 6 h to prepare an autolyzed product;

[0124] 5. Add aminopeptidase and flavor neutral protease to the autolyzed product prepared in step (4), wherein the amount of aminopeptidase and flavor neutral protease added is 0.3% and 0.2% of the dry weight of the yeast cell wall, respectively. Enzyme hydrolysis is carried out at 55° C. for 18 h. After the enzymatic hydrolysis, the enzyme is inactivated at 85° C. for 30 min to prepare an enzymatic hydrolysis product;

[0125] 6. After the enzymatic hydrolysis product prepared in step (5) is cooled to 60° C., it is centrifuged and the enzymatic hydrolysis supernatant is collected;

[0126] 7. The enzymatic supernatant collected in step (6) was subjected to vacuum evaporation and concentration at 65°C until the solid content was 33%;

[0127] 8. The product after evaporation and concentration in step (7) was spray-dried using a spray dryer to obtain a powdered yeast extract. The inlet air temperature of the spray dryer was 180° C., and the outlet air temperature was 100° C.

[0128] The yeast extracts prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to physical and chemical index tests and moisture absorption resistance tests. The test results are shown in Table 1 below.

[0129] The test method for moisture absorption resistance is as follows: yeast extract is placed in an open environment at 25°C and 50% humidity for 2 hours, and the changes in the appearance of the yeast extract are observed.

[0130] Figure 1 The comparison of the yeast extracts prepared in Example 3 and Comparative Example 1 after being left open for 1 hour in an environment of 25°C and 50% humidity is shown. Figure 1 It can be seen that after standing for 1 hour, the yeast extract prepared in Example 3 is still in a dry powdery state without any agglomeration and has good fluidity, while the yeast extract prepared in Comparative Example 1 has already absorbed moisture and agglomerated and has no fluidity.

[0131] Table 1 Physical and chemical indicators and moisture absorption resistance of yeast extract

[0132]

[0133] As can be seen from Table 1, the yeast extracts prepared in Examples 1 to 3 and Comparative Examples 1 to 3 all have good physical and chemical properties. However, in comparison, the yeast extracts prepared in Examples 1 to 3 have better moisture absorption resistance.

[0134] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments 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.

[0135] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the scope of the present invention, all of which fall within the scope of protection of this application. Therefore, the scope of protection of this patent application shall be determined by the appended claims.

Claims

1. A method for preparing a moisture-resistant yeast extract, characterized in that: The steps include: The yeast suspension is heated to 90°C to 95°C, kept warm for 2 hours to 5 hours, solid-liquid separation is performed, and the solid phase is collected to obtain yeast cell walls; preparing the yeast cell walls into a yeast cell wall suspension; Active yeast is added to the yeast cell wall suspension to perform endogenous enzyme autolysis to prepare an autolysis product; the amount of active yeast added is 0.5% to 2% of the dry weight of the yeast cell wall; the temperature for endogenous enzyme autolysis is 45° C. to 60° C., and the time is 4 hours to 8 hours; Adding papain, aminopeptidase and flavor neutral protease to the autolysis product for exogenous enzyme hydrolysis to prepare an enzymatic hydrolysis product; the amount of papain added is 0.01% to 0.5% of the dry weight of the yeast cell wall; the amount of aminopeptidase added is 0.01% to 0.5% of the dry weight of the yeast cell wall; the amount of flavor neutral protease added is 0.01% to 0.5% of the dry weight of the yeast cell wall; the temperature of the exogenous enzyme hydrolysis is 50° C. to 65° C., and the time is 16 hours to 20 hours; and The enzymatic supernatant is separated from the enzymatic hydrolysis product to prepare a moisture absorption resistant yeast extract.

2. The method for preparing the moisture-resistant yeast extract according to claim 1, wherein The yeast concentration in the yeast suspension is 100 g / L to 150 g / L.

3. The method for preparing the moisture absorption resistant yeast extract according to claim 1 or 2, characterized in that: The yeast cell wall concentration in the yeast cell wall suspension is 100 g / L to 150 g / L.

4. The method for preparing the moisture-resistant yeast extract according to claim 1 or 2, characterized in that: The following steps are also included: The enzymatic hydrolysis supernatant is evaporated, concentrated and spray-dried.

5. The method for preparing the moisture-resistant yeast extract according to claim 4, wherein: The steps of evaporating, concentrating and spray-drying the enzymatic supernatant satisfy at least one of the following conditions: (A) The temperature of evaporation and concentration is 50℃~80℃; (B) the solid content of the product obtained after evaporation and concentration is 30% to 35%; and (C) The inlet air temperature of the spray drying is 150℃~200℃, and the outlet air temperature is 95℃~105℃.

6. A moisture-resistant yeast extract, characterized in that: It is prepared by the method described in any one of claims 1 to 5.

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