A natural ginger bubble flavor base and a method for preparing the same

Abstract

This invention relates to a natural pickled ginger flavor base and its preparation method. The preparation method includes the following steps: fermented and matured pickled ginger is washed, drained of surface moisture, first frozen at -18℃ to -20℃, then thawed at 4℃ to 10℃, and finally pulverized to obtain a pickled ginger slurry with uniform particle size; the pickled ginger slurry, water, and ethanol are mixed, the pH is adjusted to 4.5, pectinase and cellulase are added for the first enzymatic hydrolysis, and simultaneously, three-frequency ultrasound is performed with an ultrasonic power of 300W and a processing frequency of 2. The process involves a first enzymatic hydrolysis at 5 / 33 / 59 kHz, a treatment temperature of 40-60℃, and a treatment time of 20-30 min. Following this, a second enzymatic hydrolysis is performed by adding hemicellulase and β-glucosidase, simultaneously with dual-frequency ultrasound at a power of 300 W, a treatment frequency of 25 / 40 kHz, a treatment temperature of 40-60℃, and a treatment time of 20-30 min. The enzymes are then inactivated, and the solution is cooled to room temperature to obtain the enzymatic hydrolysate. The hydrolysate is then subjected to solid-liquid separation and concentration to obtain the natural pickled ginger flavor base. This invention significantly improves the extraction rate of flavor substances and maximizes the preservation of the natural flavor profile of pickled ginger through the synergistic effect of frequency-sweeping ultrasound and stepwise enzymatic hydrolysis.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology. Specifically, this invention relates to a natural pickled ginger flavor base and its preparation method. Background Technology

[0002] The food industry is rapidly developing towards "natural, nutritious, and healthy" products, with clean labeling becoming a core driver of product innovation. Natural flavor bases, offering authentic and full-bodied flavor experiences and meeting consumers' demands for safety and naturalness, are largely replacing artificial flavorings. Pickled ginger, a traditional fermented food, develops a mellow sour aroma, rich flavor, and abundant esters through microbial fermentation, resulting in a more complex flavor profile than fresh ginger. Efficiently and precisely extracting and enriching the characteristic flavors of pickled ginger to prepare high-quality natural flavor bases is of great significance for modernizing traditional foods and developing new healthy seasoning products.

[0003] Currently, techniques for extracting flavor compounds from ginger raw materials mainly employ steam distillation, organic solvent extraction, enzymatic hydrolysis, and conventional ultrasound-assisted extraction. These methods have certain drawbacks: steam distillation involves high temperatures, which may destroy or volatilize heat-sensitive flavor components, resulting in flavor distortion; organic solvent extraction may leave solvent residues, affecting the naturalness and safety of the product, and its extraction efficiency is limited; enzymatic hydrolysis offers mild conditions and high specificity, but suffers from low hydrolysis efficiency, long processing time, and incomplete destruction of cell structures, especially for plant raw materials with dense cell walls, resulting in limited dissolution of flavor compounds and low extraction efficiency. Therefore, developing a method that overcomes these shortcomings and efficiently and completely extracts the natural flavor components of pickled ginger is of great significance for improving the quality and added value of natural pickled ginger flavor base materials. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing natural pickled ginger flavor base material using a frequency-sweeping ultrasound-assisted enzymatic hydrolysis technique that achieves high extraction rate, realistic flavor, and high efficiency. This method significantly improves the extraction rate of flavor substances and maximizes the preservation of the natural flavor profile of pickled ginger through the synergistic effect of frequency-sweeping ultrasound and stepwise enzymatic hydrolysis.

[0005] The present invention adopts the following technical solution:

[0006] Firstly,

[0007] This invention provides a method for preparing a natural pickled ginger flavor base, comprising the following steps:

[0008] S1: After the fermented ginger is washed and drained, it is first frozen at -18℃~-20℃, then thawed at 4℃~10℃, and finally crushed to obtain pickled ginger slurry with uniform particle size.

[0009] S2: Mix the pickled ginger slurry, water, and ethanol, adjust the pH to 4.5, add pectinase and cellulase for the first enzymatic hydrolysis, and simultaneously perform tri-frequency ultrasound at a power of 300W, a frequency of 25 / 33 / 59kHz, a temperature of 40-60℃, and a treatment time of 20-30min. After the first enzymatic hydrolysis, add hemicellulase and β-glucosidase for the second enzymatic hydrolysis, and simultaneously perform dual-frequency ultrasound at a power of 300W, a frequency of 25 / 40kHz, a temperature of 40-60℃, and a treatment time of 20-30min. Then inactivate the enzymes, cool to room temperature, and obtain the enzymatic hydrolysate.

[0010] The amount of pectinase added is 0.01% to 0.5% of the weight of the pickled ginger slurry, the amount of cellulase added is 0.8% to 5% of the weight of the pickled ginger slurry, the amount of hemicellulase added is 0.4% to 2% of the weight of the pickled ginger slurry, and the amount of β-glucosidase added is 2% to 10% of the weight of the pickled ginger slurry.

[0011] S3: After solid-liquid separation and concentration of the enzymatic hydrolysate, a natural pickled ginger flavor base is obtained.

[0012] In some embodiments, in step S1, the freezing time is 12-24 hours and the thawing time is 6-12 hours. In one specific embodiment, the freezing time is 16 hours and the thawing time is 8 hours.

[0013] In some embodiments, in step S2, the mass ratio of ginger slurry, water, and ethanol is 1:(3~5):(1~2). In some preferred embodiments, the mass ratio is 1:3:1.

[0014] In some preferred embodiments, in step S2, the amount of pectinase added is 0.05% to 0.1% of the weight of the pickled ginger slurry, the amount of cellulase added is 2.5% to 3% of the weight of the pickled ginger slurry, the amount of hemicellulase added is 0.6% to 1% of the weight of the pickled ginger slurry, and the amount of β-glucosidase added is 6% to 7% of the weight of the pickled ginger slurry.

[0015] In some more preferred embodiments, in step S2, the amount of pectinase added is 0.09% of the mass of the pickled ginger slurry, the amount of cellulase added is 2.96% of the mass of the pickled ginger slurry, the amount of hemicellulase added is 0.80% of the mass of the pickled ginger slurry, and the amount of β-glucosidase added is 6.27% of the mass of the pickled ginger slurry.

[0016] In some embodiments, in step S2, the pH is adjusted using a citrate-sodium citrate buffer solution.

[0017] In some embodiments, in step S2, in tri-frequency ultrasound, the three frequencies cycle repeatedly, with a frequency sweep cycle period of 2 minutes; in dual-frequency ultrasound, the two frequencies cycle repeatedly, with a frequency sweep cycle period of 2 minutes.

[0018] In some embodiments, in step S2, the temperature of the first enzymatic hydrolysis is 50°C and the hydrolysis time is 25 min, and the temperature of the second enzymatic hydrolysis is 50°C and the hydrolysis time is 25 min.

[0019] In some embodiments, in step S2, enzyme inactivation refers to maintaining the temperature at 85-95°C for 5-10 minutes.

[0020] In some embodiments, in step S3, the solid-liquid separation involves cooling the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuging it at 3000-5000 rpm for 10-20 min, removing the residue precipitate, and collecting the clear extract.

[0021] In some embodiments, in step S3, the concentration refers to concentration under vacuum conditions of 0.06-0.09 MPa and 50-65°C until the solid content is 20%-30%, thereby obtaining a natural pickled ginger flavor base.

[0022] Secondly,

[0023] The present invention also provides a natural pickled ginger flavor base, which is prepared by the steps of the above preparation method.

[0024] The present invention has the following advantages and beneficial effects:

[0025] (1) The extraction rate of flavor substances is greatly improved by the synergistic effect of sweep frequency ultrasound and stepwise enzymatic hydrolysis, and the natural flavor profile of pickled ginger is preserved to the maximum extent.

[0026] (2) The method of the present invention adopts a freezing-thawing-crushing pretreatment method for pickled ginger raw materials, which can greatly improve the efficiency of subsequent coupled processing. After the pickled ginger is frozen, the ice crystals formed inside the cells will pierce the cell walls and cell membranes, and the cell contents are more easily released after thawing. On this basis, pulping is carried out, which can form a more uniform material system that is more conducive to the action of enzymes and ultrasound compared with direct pulping, thereby achieving efficient extraction.

[0027] (3) The method of the present invention performs stepwise enzymatic hydrolysis, which provides the enzyme with a substrate environment closer to its optimal function, avoids competitive inhibition between enzymes, and allows the enzyme's catalytic efficiency and specificity to be fully utilized, thus achieving the optimization of the enzymatic hydrolysis process.

[0028] (4) This invention uses frequency sweeping ultrasound coupled with enzymatic hydrolysis to improve extraction efficiency. First, pectinase and cellulase are used in the primary cell wall disruption stage, and high-intensity, wide-spectrum (e.g., 25 / 33 / 59kHz three-frequency) frequency sweeping ultrasound is used to more thoroughly break the cell wall. Then, hemicellulase and β-glucosidase are used in the secondary enzymatic hydrolysis, and 25 / 40kHz dual-frequency frequency sweeping ultrasound is matched for treatment, which accelerates the dissolution of flavor substances. This application produces a synergistic effect by real-time coupling of frequency sweeping ultrasound and enzymatic hydrolysis. Under the action of ultrasound, the enzyme is more likely to bind to the substrate, which greatly accelerates the dissolution of flavor substances, significantly shortens the processing time, and improves the overall extraction rate of the target flavor substances. Attached Figure Description

[0029] Figure 1 The graph shows the effect of the ratio of compound enzyme preparations on sensory scores.

[0030] Figure 2 Flavor radar charts for pickled ginger, Exploratory Example 32, and Exploratory Example 2.

[0031] Figure 3 Flavor radar charts for pickled ginger, Exploratory Example 32, and Example 1. Detailed Implementation

[0032] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0033] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0034] Unless otherwise stated, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art.

[0035] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0036] The terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only as non-exhaustive enumerations and should be understood not to constitute a closed-ended limitation on quantity.

[0037] In the exploratory and exemplary embodiments of this invention, the natural pickled ginger flavor base was tested through sensory evaluation. A panel of 12 professional evaluators was selected and trained in professional sensory evaluation. The natural pickled ginger flavor base from the exemplary and exploratory embodiments was evaluated using a water-based method. A 1% concentration solution of the flavor base prepared with water was provided for smelling and tasting. The sensory evaluators scored each flavor base, and the average value was taken.

[0038] The sources of raw materials involved in the exploratory examples and embodiments of the present invention are as follows:

[0039] Pectinase: Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd., 300,000 U / g;

[0040] Cellulase: Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd., SPE-017, 3500U / g;

[0041] Hemicellulase: Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd., 50000U / g;

[0042] β-glucosidase: Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd., 1000U / g;

[0043] The following are exploratory examples (comparative examples) and embodiments of the present invention.

[0044] Exploration Example 1

[0045] A method for preparing a natural pickled ginger flavoring base includes the following steps:

[0046] (1) Raw material pretreatment: Select fermented and mature pickled ginger (such as Yingpeng pickled ginger), wash and drain the surface water, crush it to obtain pickled ginger slurry with uniform particle size;

[0047] (2) Sweeping-frequency ultrasound-assisted enzymatic hydrolysis: The pickled ginger slurry, water, and ethanol were mixed at a mass ratio of 1:3:1. A citrate-sodium citrate buffer solution was added to adjust the pH to 5.0 and maintain stability. The mixture was then placed in a sweeping-frequency ultrasound extraction device. A compound enzyme preparation was added, comprising 0.05% pectinase, 4.0% cellulase, 0.4% hemicellulase, and 10.0% β-glucosidase by weight of the pickled ginger slurry. Simultaneously, the sweeping-frequency ultrasound device was activated, allowing the enzymatic hydrolysis reaction to proceed synchronously under the sweeping ultrasonic field. The ultrasonic power was set to 300W, the processing frequency to 40kHz, the processing temperature to 50℃, and the processing time to 50min.

[0048] (3) Enzyme inactivation treatment: After extraction, the mixture is rapidly heated to 90°C and kept for 10 minutes to inactivate the enzyme.

[0049] (4) Solid-liquid separation: Cool the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuge it for 15 min using a centrifuge (5000 rpm) to remove the residue and collect the clear extract.

[0050] (5) Concentration: The clarified extract is placed in a vacuum concentration device and concentrated under vacuum (0.06MPa) and 60℃ conditions until the solid content is about 25% to obtain liquid natural pickled ginger flavor base.

[0051] Exploration Example 2:

[0052] The difference from Exploratory Example 1 is that step (1) is different, while the other steps are the same as in Exploratory Example 1.

[0053] The steps of Exploration Example 2 (1), namely the raw material pretreatment steps, are as follows: Select fermented and mature pickled ginger, wash and drain the surface water, and adopt the pretreatment method of freezing-thawing-crushing: first freeze at -18℃ for 16 hours, then slowly thaw at 4℃ for 8 hours, and finally crush to obtain pickled ginger slurry with uniform particle size.

[0054] Characteristic flavor compounds (myrcene, phellandrene, gingerene, eucalyptol, geraniol, geranialdehyde, and geraniyl acetate) of pickled ginger were analyzed using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS). 1 g of pickled ginger slurry was weighed and placed in a 15 mL headspace extraction vial. The vial was sealed and placed in a constant temperature heater at 50 °C for 30 min to equilibrate. Then, a 50 / 30 μm DVB / CAR / PDMS extraction head was exposed to the headspace at 50 °C for 30 min. Subsequently, the adsorbed extraction head was removed and inserted into the gas chromatograph inlet for desorption at 250 °C for 10 min, while GC-MS was initiated to acquire data. GC-MS analysis conditions were as follows: chromatographic column: DB-5 MS quartz capillary column (30m × 0.25mm × 0.25 μm); carrier gas: helium; flow rate: 1 mL / min; temperature program: initial temperature 50℃, hold for 2 min, increase to 180℃ at 3℃ / min, then increase to 250℃ at 10℃ / min, hold for 10 min. Mass spectrometry conditions: electron impact ion source (EI), detection ion mass range: (m / z) 30~450 u; interface temperature: 280℃; ion source temperature: 230℃; NIST library was used for spectral library search. Results are shown in Table 1.

[0055] Table 1. Comparison of Characteristic Volatile Flavor Compounds in Pickled Ginger and Exploratory Examples 1-2

[0056] As shown in Table 1, the pretreatment method of freezing-thawing-crushing the raw material of pickled ginger increased the total relative content of characteristic flavor substances (myrcene, phellandrene, gingerene, eucalyptol, geraniol, geranialdehyde, and geraniyl acetate) from 11.932% to 15.901%, and the retention rate of characteristic flavor substances increased from 29.23% to 38.95%. This indicates that the pretreatment method of freezing-thawing-crushing can greatly improve the extraction efficiency. After light freezing, the ice crystals formed in the cells of fermented pickled ginger can pierce the cell walls and cell membranes, making it easier for the cell contents to flow out after thawing. On this basis, pulping can form a more uniform material system that is more conducive to the action of enzymes and ultrasound compared to direct pulping, thereby promoting the extraction of characteristic flavor substances and resulting in a higher retention rate of characteristic flavor substances.

[0057] Explore Example 3-31

[0058] A method for preparing a natural pickled ginger flavoring base includes the following steps:

[0059] 1. Raw material pretreatment: Select fermented and mature pickled ginger, wash and drain the surface water, and adopt the pretreatment method of freezing-thawing-crushing: first freeze at -18℃ for 16 hours, then slowly thaw at 4℃ for 8 hours, and finally crush to obtain pickled ginger slurry with uniform particle size.

[0060] 2. Sweeping-frequency ultrasound-assisted enzymatic hydrolysis: Ginger slurry, water, and ethanol were mixed at a mass ratio of 1:3:1. A citrate-sodium citrate buffer solution was added to adjust the pH to 5.0 and maintained stable. The mixture was then placed in a sweeping-frequency ultrasound extraction device. A compound enzyme preparation was added, comprising pectinase, cellulase, hemicellulase, and β-glucosidase, with the amount of each enzyme added ranging from 0.01% to 10% of the ginger slurry mass. Simultaneously, the sweeping-frequency ultrasound device was activated, allowing the enzymatic hydrolysis reaction to proceed synchronously under the sweeping ultrasonic field. The ultrasonic power was set to 300W, the processing frequency to 40kHz, the processing temperature to 50℃, and the processing time to 50min.

[0061] 3. Enzyme inactivation treatment: After extraction, the mixture is rapidly heated to 90°C and kept at that temperature for 10 minutes to inactivate the enzyme.

[0062] 4. Solid-liquid separation: Cool the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuge at 5000 rpm for 15 min, remove the residue and precipitate, and collect the clear extract.

[0063] 5. Concentration: Place the clarified extract in a vacuum concentration device and concentrate it under vacuum (0.06MPa) and 60℃ conditions until the solid content is about 25%, to obtain liquid natural pickled ginger flavor base.

[0064] Response surface optimization experiments were designed with different amounts of different enzymes, and the optimal ratio of the compound enzyme preparation was determined by sensory evaluation. The sensory evaluation criteria of pickled ginger flavor base are shown in Table 2, and the results of the orthogonal experimental design are shown in Table 3.

[0065] Table 2 Sensory Evaluation Criteria for Pickled Ginger Flavor Base

[0066]

[0067] Table 3. Response surface methodology and response value test results for compound enzyme formulation.

[0068]

[0069] Table 4. Analysis of Variance Table for Regression Model of Compound Enzyme Preparation Ratio

[0070]

[0071] Analysis of the data in Tables 3 and 4 leads to the following conclusions: the correlation coefficient R of the model... 2 =0.9015, indicating that the model fits the experiment well, and the optimal ratio of enzyme preparation can be determined using the regression equation of this model. Table 4 shows that the multiple regression model is highly significant (P<0.01), and the difference in the lack-of-fit terms is not significant (P>0.05), indicating that the multiple regression simulation equation can fit the changes in the actual predicted values ​​well, with a small theoretical error. From the F-values ​​of each factor, the order of influence of each factor on sensory scores is: pectinase addition (A) > β-glucosidase addition (D) > cellulase addition (B) > hemicellulase addition (C). Based on the response surface model (see... Figure 1 The predicted optimal process is: 0.09% pectinase, 2.96% cellulase, 0.80% hemicellulase, and 6.27% β-glucosidase. Under these conditions, the theoretical sensory score can reach 88.3 points.

[0072] Exploration Example 32

[0073] A method for preparing a natural pickled ginger flavoring base includes the following steps:

[0074] (1) Raw material pretreatment: Select fermented and mature pickled ginger, wash and drain the surface water, and adopt the pretreatment method of freezing-thawing-crushing: first freeze at -18℃ for 16 hours, then slowly thaw at 4℃ for 8 hours, and finally crush to obtain pickled ginger slurry with uniform particle size.

[0075] (2) Sweeping frequency ultrasound-assisted enzymatic hydrolysis: The pickled ginger slurry, water, and ethanol were mixed in a mass ratio of 1:3:1. The pH was adjusted to 5.0 and maintained stable by adding citrate-sodium citrate buffer solution, and then placed in a sweeping frequency ultrasound extraction device. A compound enzyme preparation was added, which included 0.09% pectinase, 2.96% cellulase, 0.80% hemicellulase, and 6.27% β-glucosidase. The sweeping frequency ultrasound device was started simultaneously so that the enzymatic hydrolysis reaction could proceed synchronously under the action of the sweeping frequency ultrasound field. The ultrasound power was set to 300W, the processing frequency to 40kHz, the processing temperature to 50℃, and the processing time to 50min.

[0076] (3) Enzyme inactivation treatment: After extraction, the mixture is rapidly heated to 90°C and kept for 10 minutes to inactivate the enzyme.

[0077] (4) Solid-liquid separation: Cool the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuge it for 15 min using a centrifuge (5000 rpm) to remove the residue and collect the clear extract.

[0078] (5) Concentration: The clarified extract is placed in a vacuum concentration device and concentrated under vacuum (0.06MPa) and 60℃ conditions until the solid content is about 25% to obtain liquid natural pickled ginger flavor base.

[0079] Table 5 Flavor Intensity Scoring Criteria

[0080]

[0081] Table 6. Flavor intensity scores for pickled ginger, Exploratory Example 32, and Exploratory Example 2.

[0082]

[0083] Flavor intensity was scored for pickled ginger, Exploratory Example 32, and Exploratory Example 2 (standards are shown in Table 5), and the results are as follows: Figure 2 As shown in Table 6, compared to the rich and distinctive flavor of pickled ginger, Exploratory Examples 32 and 2 showed significant reductions in core characteristic dimensions such as ginger aroma, fermentation aroma, and spiciness. Exploratory Example 2, in particular, exhibited significantly lower ginger aroma and spiciness intensity than pickled ginger. However, the overall flavor profile of Exploratory Example 32 was closer to that of pickled ginger than that of Exploratory Example 2. This indicates that optimizing the ratio of compound enzyme preparations can improve the realism of the pickled ginger flavor base, resulting in a more balanced and mellow flavor.

[0084] Exploration Example 33

[0085] The difference from Exploratory Example 32 is that in step (2) of Exploratory Example 33, the pH is controlled at 4.5, while the rest is the same as Exploratory Example 32.

[0086] Table 7 Comparison of Characteristic Volatile Flavor Compounds Composition of Pickled Ginger, Exploratory Example 33, and Exploratory Example 32

[0087]

[0088] As shown in Table 7, in order to fully utilize the optimal combination of enzyme preparations, the pH of the system was adjusted to 4.5 by adding a citrate-sodium citrate buffer solution. Compared with pH=5, the total relative content of characteristic flavor substances in pickled ginger (myrcene, phellandrene, gingerene, eucalyptol, geraniol, geranialdehyde, and geraniyl acetate) increased from 20.105% to 23.669%, and the retention rate of characteristic flavor substances increased from 49.25% to 57.98%. This indicates that the enzyme combination exhibits better enzyme activity at pH 4.5. Frequency sweeping ultrasound may cause slight fluctuations in local temperature, which in turn affects the pH value. A stable and suitable pH is crucial to ensuring enzyme activity and reaction consistency. Using an optimal pH buffer system to maintain a stable reaction environment can improve the extraction rate of flavor substances.

[0089] Exploration Example 34

[0090] A method for preparing a natural pickled ginger flavoring base includes the following steps:

[0091] (1) Raw material pretreatment: Select fermented and mature pickled ginger, wash and drain the surface water, and adopt the pretreatment method of freezing-thawing-crushing: first freeze at -18℃ for 16 hours, then slowly thaw at 4℃ for 8 hours, and finally crush to obtain pickled ginger slurry with uniform particle size.

[0092] (2) Sweeping-frequency ultrasound-assisted enzymatic hydrolysis: The pickled ginger slurry, water, and ethanol were mixed at a mass ratio of 1:3:1. A citrate-sodium citrate buffer solution was added to adjust the pH to 4.5 and maintain stability. The mixture was then placed in a sweeping-frequency ultrasound extraction device. A two-step enzymatic hydrolysis method was used. First, 0.09% pectinase and 2.96% cellulase were added, and the sweeping-frequency ultrasound device was started simultaneously to allow the enzymatic hydrolysis reaction to proceed synchronously under the sweeping ultrasonic field. The ultrasonic power was set to 300W, the treatment frequency to 40kHz, the treatment temperature to 50℃, and the treatment time to 25min. After one enzymatic hydrolysis step, 0.80% hemicellulase and 6.27% β-glucosidase were added, and the mixture was treated for another 25min under the same conditions.

[0093] (3) Enzyme inactivation treatment: After extraction, the mixture is rapidly heated to 90°C and kept for 10 minutes to inactivate the enzyme.

[0094] (4) Solid-liquid separation: Cool the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuge it for 15 min using a centrifuge (5000 rpm) to remove the residue and collect the clear extract.

[0095] (5) Concentration: The clarified extract is placed in a vacuum concentration device and concentrated under vacuum (0.06MPa) and 60℃ conditions until the solid content is about 25% to obtain liquid natural pickled ginger flavor base.

[0096] Exploration Example 35

[0097] A method for preparing a natural pickled ginger flavoring base includes the following steps:

[0098] (1) Raw material pretreatment: Select fermented and mature pickled ginger, wash and drain the surface water, and adopt the pretreatment method of freezing-thawing-crushing: first freeze at -18℃ for 16 hours, then slowly thaw at 4℃ for 8 hours, and finally crush to obtain pickled ginger slurry with uniform particle size.

[0099] (2) Sweeping-frequency ultrasound-assisted enzymatic hydrolysis: The pickled ginger slurry, water, and ethanol were mixed at a mass ratio of 1:3:1. A citrate-sodium citrate buffer solution was added to adjust the pH to 4.5 and maintain stability. The mixture was then placed in a sweeping-frequency ultrasound extraction device. A two-step enzymatic hydrolysis method was used. First, 0.09% pectinase and 2.96% cellulase were added, and the sweeping-frequency ultrasound device was started simultaneously to allow the enzymatic hydrolysis reaction to proceed synchronously under the action of the sweeping ultrasonic field. The ultrasonic power was set to 300W, the treatment frequency to 25 / 40kHz (sweeping cycle 2 min), the treatment temperature to 50℃, and the treatment time to 25 min. After one enzymatic hydrolysis, 0.80% hemicellulase and 6.27% β-glucosidase were added, and treatment continued for another 25 min under the same conditions.

[0100] (3) Enzyme inactivation treatment: After extraction, the mixture is rapidly heated to 90°C and kept for 10 minutes to inactivate the enzyme.

[0101] (4) Solid-liquid separation: Cool the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuge it for 15 min using a centrifuge (5000 rpm) to remove the residue and collect the clear extract.

[0102] (5) Concentration: The clarified extract is placed in a vacuum concentration device and concentrated under vacuum (0.06MPa) and 60℃ conditions until the solid content is about 25% to obtain liquid natural pickled ginger flavor base.

[0103] Example 1

[0104] A method for preparing a natural pickled ginger flavoring base includes the following steps:

[0105] (1) Raw material pretreatment: Select fermented and mature pickled ginger, wash and drain the surface water, and adopt the pretreatment method of freezing-thawing-crushing: first freeze at -18℃ for 16 hours, then slowly thaw at 4℃ for 8 hours, and finally crush to obtain pickled ginger slurry with uniform particle size.

[0106] (2) Sweeping-frequency ultrasound-assisted enzymatic hydrolysis: The pickled ginger slurry, water, and ethanol were mixed at a mass ratio of 1:3:1. A citrate-sodium citrate buffer solution was added to adjust the pH to 4.5 and maintain stability. The mixture was then placed in a sweeping-frequency ultrasound extraction device. A two-step enzymatic hydrolysis method was used. First, 0.09% pectinase and 2.96% cellulase were added, and the sweeping-frequency ultrasound device was started simultaneously to allow the enzymatic hydrolysis reaction to proceed synchronously under the sweeping ultrasonic field. The ultrasonic power was set to 300W, the processing frequency to 25 / 33 / 59kHz (sweeping cycle 2min), the processing temperature to 50℃, and the processing time to 25min. After one enzymatic hydrolysis step, 0.80% hemicellulase and 6.27% β-glucosidase were added, and the sweeping-frequency ultrasound device was started simultaneously to allow the enzymatic hydrolysis reaction to proceed synchronously under the sweeping ultrasonic field. The ultrasonic power was set to 300W, the processing frequency to 25 / 40kHz (sweeping cycle 2min), the processing temperature to 50℃, and the processing time to 25min.

[0107] (3) Enzyme inactivation treatment: After extraction, the mixture is rapidly heated to 90°C and kept for 10 minutes to inactivate the enzyme.

[0108] (4) Solid-liquid separation: Cool the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuge it for 15 min using a centrifuge (5000 rpm) to remove the residue and collect the clear extract.

[0109] (5) Concentration: The clarified extract is placed in a vacuum concentration device and concentrated under vacuum (0.06MPa) and 60℃ conditions until the solid content is about 25% to obtain liquid natural pickled ginger flavor base.

[0110] The samples obtained from Exploratory Examples 33-35 and Example 1 were pretreated using headspace solid-phase microextraction. The characteristic flavor compounds of pickled ginger, including myrcene, phellandrene, gingerene, eucalyptol, geraniol, geranialdehyde, and geraniyl acetate, were analyzed by GC-MS. The main characteristic flavor compounds in pickled ginger and pickled ginger flavor bases prepared by different sweep ultrasonic frequencies were compared. The results are shown in Table 8.

[0111] Table 8 Comparison of characteristic volatile flavor compounds in pickled ginger, exploratory examples 33-35, and example 1

[0112]

[0113] The results of Exploratory Examples 33 and 34 show that stepwise enzymatic hydrolysis can increase the total relative content of characteristic flavor compounds in pickled ginger from 23.669% to 26.606%. This may be because pectinase and cellulase are the main forces in destroying cell walls. Pectinase can decompose the pectin in the intercellular layer, and cellulase attacks the cellulose framework of the cell wall. This step can greatly increase the porosity of the cell wall. Then, the addition of hemicellulase and β-glucosidase can act more deeply on the exposed substrate, transform flavor precursors, and achieve higher extraction efficiency.

[0114] The results of Exploratory Examples 34 and 35 show that dual-frequency ultrasound can increase the total relative content of characteristic flavor substances in pickled ginger from 26.606% to 28.079%. This indicates that dual-frequency sweep ultrasound can produce a stronger cavitation effect than single-frequency ultrasound, making the cell structure of pickled ginger tissue looser and significantly increasing the enzyme action sites, thereby more effectively promoting the extraction of characteristic flavor substances.

[0115] Based on the results of Exploratory Example 35 and Example 1, the total relative content of characteristic flavor substances in pickled ginger can be increased from 28.079% to 31.247% by using a combination of different frequency sweeping ultrasound. In the first step of pectinase and cellulase hydrolysis, stronger high-frequency ultrasound can decompose the cell wall to a greater extent, providing a foundation for the subsequent conversion of flavor substances. After the main structure of the cell wall has been severely damaged, the second step uses a mature 25 / 40kHz dual-frequency sweep to efficiently assist in the conversion of flavor substances in the remaining enzymatic hydrolysis reaction.

[0116] Table 9. Flavor intensity scores for pickled ginger, Exploratory Example 32, and Example 1.

[0117]

[0118] Flavor intensity was scored for pickled ginger, Exploratory Example 32, and Example 1, and the results are as follows: Figure 3 As shown, compared to the rich and distinctive flavor of pickled ginger, Exploratory Example 32 and Example 1 show a significant reduction in core characteristic dimensions such as ginger aroma, fermentation aroma, and savory aroma. However, the overall flavor profile of Example 1 is closer to that of pickled ginger than that of Exploratory Example 32. This indicates that the combination of stepwise enzymatic hydrolysis and frequency sweeping ultrasound can improve the fidelity of the pickled ginger flavor base, making its flavor more balanced and mellow.

[0119] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0120] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a natural pickled ginger flavor base, characterized in that, Includes the following steps: S1: After the fermented ginger is washed and drained, it is first frozen at -18℃~-20℃, then thawed at 4℃~10℃, and finally crushed to obtain pickled ginger slurry with uniform particle size. S2: Mix the pickled ginger slurry, water, and ethanol, adjust the pH to 4.5, add pectinase and cellulase for the first enzymatic hydrolysis, and simultaneously perform tri-frequency ultrasound at a power of 300W, a frequency of 25 / 33 / 59kHz, a temperature of 40-60℃, and a treatment time of 20-30min. After the first enzymatic hydrolysis, add hemicellulase and β-glucosidase for the second enzymatic hydrolysis, and simultaneously perform dual-frequency ultrasound at a power of 300W, a frequency of 25 / 40kHz, a temperature of 40-60℃, and a treatment time of 20-30min. Then inactivate the enzymes, cool to room temperature, and obtain the enzymatic hydrolysate. The amount of pectinase added is 0.01%~0.5% of the weight of the pickled ginger slurry, the amount of cellulase added is 0.8%~5% of the weight of the pickled ginger slurry, the amount of hemicellulase added is 0.4%~2% of the weight of the pickled ginger slurry, and the amount of β-glucosidase added is 2%~10% of the weight of the pickled ginger slurry. S3: After solid-liquid separation and concentration of the enzymatic hydrolysate, a natural pickled ginger flavor base is obtained.

2. The method for preparing a natural pickled ginger flavor base according to claim 1, characterized in that, In step S1, the freezing time is 12-24 hours and the thawing time is 6-12 hours.

3. The method for preparing a natural pickled ginger flavor base according to claim 1, characterized in that, In step S2, the mass ratio of ginger slurry, water, and ethanol is 1:(3~5):(1~2), preferably 1:3:

1.

4. The method for preparing a natural pickled ginger flavor base according to claim 1, characterized in that, In step S2, the amount of pectinase added is 0.05%~0.1% of the weight of the pickled ginger slurry, the amount of cellulase added is 2.5%~3% of the weight of the pickled ginger slurry, the amount of hemicellulase added is 0.6%~1% of the weight of the pickled ginger slurry, and the amount of β-glucosidase added is 6%~7% of the weight of the pickled ginger slurry.

5. The method for preparing a natural pickled ginger flavor base according to claim 4, characterized in that, In step S2, the amount of pectinase added is 0.09% of the mass of the pickled ginger slurry, the amount of cellulase added is 2.96% of the mass of the pickled ginger slurry, the amount of hemicellulase added is 0.80% of the mass of the pickled ginger slurry, and the amount of β-glucosidase added is 6.27% of the mass of the pickled ginger slurry.

6. The method for preparing a natural pickled ginger flavor base according to claim 1, characterized in that, In step S2, during tri-frequency ultrasound, the three frequencies cycle repeatedly, with a sweep cycle period of 2 minutes; during dual-frequency ultrasound, the two frequencies cycle repeatedly, with a sweep cycle period of 2 minutes.

7. The method for preparing a natural pickled ginger flavor base according to claim 1, characterized in that, In step S2, the temperature of the first enzymatic hydrolysis is 50℃ and the time is 25 min. The temperature of the second enzymatic hydrolysis is 50℃ and the time is 25 min.

8. The method for preparing a natural pickled ginger flavor base according to claim 1, characterized in that, In step S3, the solid-liquid separation involves cooling the enzyme hydrolysate after enzyme inactivation to room temperature, centrifuging it at 3000-5000 rpm for 10-20 min, removing the residue precipitate, and collecting the clear extract.

9. The method for preparing a natural pickled ginger flavor base according to claim 1, characterized in that, In step S3, the concentration refers to concentration under vacuum conditions of 0.06-0.09 MPa and 50-65°C until the solid content is 20%-30%, thus obtaining a natural pickled ginger flavor base.

10. A natural pickled ginger flavoring base, characterized in that, It is prepared by the steps of the preparation method according to any one of claims 1-9.

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