Bamboo shoot flavor sake and preparation method thereof

Abstract

The invention discloses bamboo shoot flavor sake and a preparation method thereof, and belongs to the technical field of food processing and brewing. The method comprises the following steps: blanching husked bamboo shoots, cooling, and crushing to prepare bamboo shoot pulp; adding water into the bamboo shoot pulp, carrying out primary enzymolysis by using cellulase and pectinase, then carrying out secondary enzymolysis by using neutral protease, then inactivating enzyme and centrifuging to obtain supernate, namely a bamboo shoot flavor precursor liquid; in the preparation process of the sake, 60%-70% of the total amount of the bamboo shoot flavor precursor liquid is added within 12-24 h after other fermentation raw materials except the bamboo shoot flavor precursor liquid are added, the remaining bamboo shoot flavor precursor liquid is added within 48-72 h after the bamboo shoot flavor precursor liquid is added for the first time, and the bamboo shoot flavor sake is obtained after fermentation is completed. The bamboo shoot flavor sake prepared by the invention has obvious bamboo shoot faint scent, mellow and sweet taste, harmonious wine body and excellent fusion degree of the bamboo shoot flavor and the sake.

Description

Technical Field

[0001] This invention belongs to the field of food processing and brewing technology, specifically relating to a bamboo shoot-flavored sake and its preparation method. Background Technology

[0002] Sake is a distinctive alcoholic beverage made from rice, rice koji (rice malt), and water through a parallel double fermentation process. Renowned for its refreshing taste, moderate alcohol content (typically 12%–18% vol%), and rich umami flavor, sake is often called "the sake that best complements food." It effectively neutralizes oils, enhances the sweetness of seafood, and preserves the original flavor of ingredients, making it suitable for a wide range of dishes, from fine dining to everyday izakaya snacks. With the rise of healthy eating trends, sake's low-purine properties (compared to beer) and high amino acid content are attracting a broader consumer base worldwide, especially women and younger consumers, who seek a pleasant buzz and a high-quality lifestyle. Traditional Ginjo sake emphasizes floral and fruity aromas, but its flavor profile is relatively understated. As the consumer market continues to demand more diversified, healthier, and flavorful alcoholic beverages, there is an urgent need to introduce distinctive natural plant flavors while retaining the elegant structure of sake, and to develop innovative categories with regional characteristics, storytelling, and added value to explore new consumption scenarios and market boundaries.

[0003] Bamboo shoots are a delicious forest ingredient produced from bamboo. Bamboo belongs to the Bambusoideae subfamily of the Poaceae family, and there are over 1,500 species worldwide, of which hundreds are edible bamboo shoot varieties. Widely distributed in East Asia and Southeast Asia, bamboo shoots are a signature ingredient deeply intertwined with the culinary cultures of these regions. Bamboo shoots are rich in dietary fiber, various amino acids (such as aspartic acid and glutamic acid), flavonoids, and minerals, possessing a unique aroma and potential antioxidant activity. Traditionally, bamboo shoots are primarily used in cooking, with their flavor compounds being less frequently used in winemaking.

[0004] Bamboo shoots possess a complex flavor profile. Their freshness primarily derives from abundant free amino acids (such as aspartic acid and glutamic acid), while their signature "fresh aroma" and "earthy aroma" originate from trace amounts of volatile substances, such as methoxyalkylpyrazine compounds. However, these characteristic flavor compounds are mostly bound within plant cells in the form of flavor precursors (such as glycoside-bound forms), and their "raw, green" components (such as certain aldehydes) can easily produce unpleasant aromas if not handled properly. The core challenge in flavor design is how to stably integrate the flavor of bamboo shoots into sake, rather than simply layering them.

[0005] Existing technologies include some blending processes that involve soaking fruits and vegetables in base liquor, or simple attempts to co-ferment the ingredients with grains. However, when using bamboo shoots as an ingredient, the following technical defects often exist: 1. Poor flavor integration: Simple soaking processes lead to flavor separation. The raw, green taste of bamboo shoots fails to organically combine with the richness of sake, and may even produce unpleasant off-flavors; 2. Unstable fermentation process: The addition of abundant soluble components (such as sugars and proteins) in bamboo shoots may interfere with the metabolic balance of the main fermentation system (yeast, Aspergillus oryzae) in sake, leading to abnormal fermentation, fluctuations in alcohol content, or the production of undesirable byproducts; 3. Poor product stability: Polyphenols and proteins in bamboo shoots can easily cause sedimentation, turbidity, or color deterioration in the finished sake during storage, affecting the product's appearance; 4. Low utilization rate of nutrients: Conventional processing methods cannot fully extract and transform the functional components in bamboo shoots, making it difficult for them to exist stably in the sake and exert their effects.

[0006] The fundamental flaw in existing technology lies in treating bamboo shoots as a passive flavor package placed into a closed, fragile fermentation black box, ignoring the sensitivity of the fermentation system as a dynamic and precise biochemical reactor to external interference, as well as the scientific principle that flavor substances need to undergo transformation rather than migration to truly integrate.

[0007] Therefore, there is an urgent need for an innovative integrated process that can systematically solve the technical challenges of efficient extraction, targeted conversion, flavor coupling, and product stabilization of bamboo shoot flavor substances while preserving the traditional essence of sake. Summary of the Invention

[0008] The purpose of this invention is to provide a bamboo shoot-flavored sake and its preparation method. A bamboo shoot aroma component, which can be recognized and utilized by the sake fermentation microbial community (Aspergillus oryzae-yeast), is extracted using bio-enzymatic hydrolysis technology and used as a flavor precursor library. This precursor is then introduced into the sake fermentation process. Through metabolic engineering, the timing and method of flavor precursor library input are precisely controlled based on the carbon and nitrogen flow dynamics during fermentation, guiding microbial metabolic flow towards the synthesis of target flavor compounds, ultimately yielding an innovative sake with a bamboo shoot aroma. The bamboo shoot-flavored sake provided by this invention represents a flavor innovation for the sake industry and possesses significant market potential and industrial value.

[0009] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention is to provide a method for preparing bamboo shoot-flavored sake, comprising the following steps: First, the peeled bamboo shoots are blanched, cooled, and crushed to prepare bamboo shoot pulp. Water is added to the bamboo shoot pulp and cellulase and pectinase are used for the first enzymatic hydrolysis, followed by neutral protease for the second enzymatic hydrolysis. Then, the enzymes are inactivated, centrifuged, and the resulting supernatant is the bamboo shoot flavor precursor liquid. In the sake preparation process, 60% to 70% of the total amount of bamboo shoot flavor precursor liquid is added within 12 to 24 hours after all other fermentation raw materials except the bamboo shoot flavor precursor liquid are added. The remaining bamboo shoot flavor precursor liquid is added within 48 to 72 hours after the first addition of the bamboo shoot flavor precursor liquid. After fermentation is completed, the bamboo shoot flavor sake is obtained.

[0010] The purpose of heat treatment of peeled bamboo shoots in this invention is to inactivate endogenous enzymes and remove some of the raw, grassy flavor substances. The first enzymatic hydrolysis of the crushed bamboo shoot pulp using cellulase and pectinase is to degrade cell walls, release intracellular soluble substances, and convert macromolecular polysaccharides into oligosaccharides or monosaccharides that are easily utilized by yeast. The second enzymatic hydrolysis using neutral protease is to release flavor-enhancing amino acids and small peptides from the bamboo shoots, forming flavor precursors. This stepwise enzymatic hydrolysis method can effectively break down large molecular proteins and polysaccharides that cause turbidity in wine.

[0011] This invention selects to add pre-prepared bamboo shoot flavor precursor liquid in stages during sake fermentation. The first addition is 12-24 hours after the start of saccharification in sake fermentation, when the initial sugar content of the mash reaches 12-15°Bx. The first addition provides sufficient nutrition for the yeast to multiply rapidly. The second addition occurs during the vigorous fermentation period, when the alcohol content of the mash reaches 6-8 vol%. The second addition mainly contributes characteristic flavor substances in the middle and late stages of fermentation and participates in secondary metabolism such as esterification, reducing the loss of volatile flavors.

[0012] Preferably, the temperature of the hot water scalding is 85-90℃ and the time is 2-3 minutes.

[0013] Preferably, the bamboo shoot particles in the bamboo shoot paste have a particle size of 50–150 μm.

[0014] Preferably, the mass ratio of the bamboo shoot pulp to water is 1:(1.5-2.5).

[0015] Preferably, the pH of the first enzymatic hydrolysis is 5.0-5.5, the temperature is 45-50℃, and the time is 1.5-2.5h.

[0016] Preferably, during the first enzymatic hydrolysis, 100,000 to 150,000 U of cellulase and 200,000 to 300,000 U of pectinase are added per gram of bamboo shoot.

[0017] Preferably, the second enzymatic hydrolysis is performed at a pH of 6.5–7.0, a temperature of 50–55°C, and a time of 1–1.5 h.

[0018] Preferably, during the second enzymatic hydrolysis, 150,000 to 250,000 U of the neutral protease are added per gram of bamboo shoot.

[0019] Optionally, the inactivation enzyme is inactivated at a temperature of 90°C for 10 minutes.

[0020] Optionally, the centrifugation speed is 4000-5000 rpm and the time is 15 min.

[0021] Preferably, in the sake preparation process, the mass ratio of peeled bamboo shoots used in the bamboo shoot flavor precursor liquid to rice used in fermentation is (0.4-0.6):1.

[0022] Preferably, the fermentation temperature of the sake is controlled as follows: 25-28°C for 0-3 days, 18-22°C for 4-10 days, and 15-18°C after 11 days, with a total fermentation time of 25-35 days.

[0023] The second technical solution of the present invention is to provide a bamboo shoot flavored sake prepared according to the above-mentioned method for preparing bamboo shoot flavored sake.

[0024] The beneficial technical effects of the present invention are as follows: This invention utilizes targeted enzymatic hydrolysis to transform macromolecular substances in bamboo shoots into flavor precursors that can be utilized and converted by yeast. This achieves flavor coupling at the microbial metabolic level during fermentation, avoiding the flavor stripping sensation associated with simple soaking methods. The resulting bamboo shoot-flavored sake possesses a distinct bamboo shoot aroma, the sweetness of rice wine, and an elegant fermentation ester aroma, exhibiting rich layers and a long-lasting aftertaste.

[0025] This invention uses bamboo shoot flavor precursor liquid instead of raw materials to participate in fermentation, which can eliminate the interference of fermentation inhibitors that may exist in bamboo shoot raw materials on the main fermentation system. The gradient addition strategy balances the carbon and nitrogen supply, avoids fermentation fluctuations caused by nutrient shock, and ensures the smoothness of the fermentation process and the stable achievement of alcohol content (the target alcohol content can be stabilized at 14-16 vol%).

[0026] The brewing process parameters provided by this invention are clear and the key control points are well-defined, making it easy to achieve standardized production. It has good potential for industrial scale-up and the resulting bamboo shoot flavored sake products have good batch consistency. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a process flow diagram for preparing bamboo shoot-flavored sake according to Example 1 of the present invention.

[0029] Figure 2 The image shows the gas phase-ion migration spectrum of the sake prepared in Example 1.

[0030] Figure 3 The gas phase-ion migration spectrum of the sake prepared in Comparative Example 1 is shown. Detailed Implementation

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0032] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0033] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] Unless otherwise specified, all raw materials and reagents used in the specific embodiments of this invention are commercially available products.

[0037] Unless otherwise specified, the room temperature mentioned in the specific embodiments of the present invention refers to a temperature of 20±10℃.

[0038] Example 1 1. Targeted preparation of bamboo shoot flavor precursor liquid 1) Raw material processing: Select fresh peeled bamboo shoots, wash them and blanch them in hot water at 85-90℃ for 3 minutes, then put them into cold water to cool them quickly. After taking them out, add water (200mL of water for every 500g of bamboo shoots) and use a high-speed blender to crush them into bamboo shoot paste with a particle size of 50-150μm.

[0039] 2) Compound enzymatic hydrolysis conversion: Add twice the weight of deionized water to the bamboo shoot pulp and inoculate with compound enzyme preparation for two-step enzymatic hydrolysis; Step 1 (polysaccharide conversion): Adjust the pH to 5.0, add cellulase (150,000 U / g bamboo shoot) and pectinase (205,000 U / g bamboo shoot), and enzymatically hydrolyze at 45℃ for 1.5 h; Step 2 (Protein / Flavor Precursor Release): Adjust pH to 7.0, add neutral protease (250,000 U / g bamboo shoots), and enzymatically hydrolyze at 55℃ for 1 hour.

[0040] 3) Enzyme inactivation and solid-liquid separation: After enzymatic hydrolysis, the temperature is rapidly raised to 90℃ and maintained for 10 minutes to inactivate the enzyme. Then, the mixture is centrifuged (5000 rpm, 15 minutes). The resulting supernatant is the bamboo shoot flavor precursor liquid, which is cooled to room temperature for later use.

[0041] 2. Step-by-step co-fermentation 1) Preparation of the main fermentation mash for sake: Following the traditional sake process, refined white rice is steamed, cooled, and then inoculated with Aspergillus oryzae (…). Aspergillus oryzae Prepare rice koji; mix rice koji, steamed rice and water in a mass ratio of 2:10:15 to begin the saccharification stage.

[0042] 2) Stepwise addition and co-fermentation: 18 hours after saccharification starts, bamboo shoot flavor precursor liquid is added to the fermentation mash for the first time; 60 hours after the first addition, the remaining bamboo shoot flavor precursor liquid is added; wherein, 500g of peeled bamboo shoots are used to make bamboo shoot flavor precursor liquid for every kilogram of white rice, and the initial addition amount of bamboo shoot flavor precursor liquid is 70%.

[0043] 3) Temperature-controlled fermentation: The entire fermentation process adopts dynamic temperature control, specifically the temperature control curve of 25℃ (3 days) → 19℃ (7 days) → 15℃ (15 days) for a total of 25 days.

[0044] 3. Post-processing and stability control 1) Filtration and clarification: After fermentation, filter the wine by pressing and add a composite clarifying agent consisting of modified diatomaceous earth (0.4g / L) and chitosan (0.1g / L) to the original wine. Let it stand at 0-4℃ for 7 days to clarify.

[0045] 2) Fine filtration and sterilization: Take the supernatant and pass it through filter cartridges with pore sizes of 1.0μm and 0.45μm for deep filtration in sequence, and finally use a microporous filter membrane with a pore size of 0.22μm for sterilization filtration.

[0046] 3) Stabilization treatment: First, perform instant pasteurization at 70℃ for 30 seconds, then immediately cool and age and store at 4-8℃ in the dark for 30 days to promote the fusion of flavors and physical stability of the sake, thus obtaining bamboo shoot flavored sake.

[0047] The process flow diagram for preparing bamboo shoot-flavored sake in Example 1 is shown below. Figure 1 .

[0048] The bamboo shoot flavored sake prepared in Example 1 is pale yellow in color and clear and transparent. According to the evaluation, it has a distinct bamboo shoot aroma, a mellow and sweet taste, and a harmonious body (characteristic flavor integration - excellent).

[0049] Example 2 1. Targeted preparation of bamboo shoot flavor precursor liquid 1) Raw material processing: Same as in Example 1.

[0050] 2) Compound enzymatic hydrolysis conversion: Add twice the weight of deionized water to the bamboo shoot pulp and inoculate with compound enzyme preparation for two-step enzymatic hydrolysis; Step 1 (polysaccharide conversion): Adjust the pH to 5.0, add cellulase (150,000 U / g bamboo shoot) and pectinase (205,000 U / g bamboo shoot), and enzymatically hydrolyze at 45℃ for 2.0 h; Step 2 (Protein / Flavor Precursor Release): Adjust pH to 7.0, add neutral protease (250,000 U / g bamboo shoots), and enzymatically hydrolyze at 55℃ for 1.2 h.

[0051] 3) Enzyme inactivation and solid-liquid separation: After enzymatic hydrolysis, the temperature is rapidly raised to 90℃ and maintained for 10 minutes to inactivate the enzyme. Then, the mixture is centrifuged (5000 rpm, 15 minutes). The resulting supernatant is the bamboo shoot flavor precursor liquid, which is cooled to room temperature for later use.

[0052] 2. Step-by-step co-fermentation 1) Preparation of the main fermentation mash for sake: Following the traditional sake process, refined white rice is steamed, cooled, and then inoculated with Aspergillus oryzae (…). Aspergillus oryzae Prepare rice koji; mix rice koji, steamed rice and water in a mass ratio of 2:10:15 to begin the saccharification stage.

[0053] 2) Stepwise addition and co-fermentation: 18 hours after saccharification starts, bamboo shoot flavor precursor liquid is added to the fermentation mash for the first time; 60 hours after the first addition, the remaining bamboo shoot flavor precursor liquid is added; wherein, each kilogram of polished white rice corresponds to 400g of peeled bamboo shoots to obtain bamboo shoot flavor precursor liquid, and the initial addition amount of bamboo shoot flavor precursor liquid is 60%.

[0054] 3) Temperature-controlled fermentation: The entire fermentation process adopts dynamic temperature control, specifically the temperature control curve of 25℃ (3 days) → 19℃ (7 days) → 15℃ (15 days) for a total of 25 days.

[0055] 3. Post-processing and stability control 1) Filtration and clarification: After fermentation, filter the wine by pressing and add a composite clarifying agent consisting of modified diatomaceous earth (0.4g / L) and chitosan (0.1g / L) to the original wine. Let it stand at 0-4℃ for 7 days to clarify.

[0056] 2) Fine filtration and sterilization: Take the supernatant and pass it through filter cartridges with pore sizes of 1.0μm and 0.45μm for deep filtration in sequence, and finally use a microporous filter membrane with a pore size of 0.22μm for sterilization filtration.

[0057] 3) Stabilization treatment: First, perform instant pasteurization at 70℃ for 30 seconds, then immediately cool and age and store at 4-8℃ in the dark for 30 days to promote the fusion of flavors and physical stability of the sake, thus obtaining bamboo shoot flavored sake.

[0058] The bamboo shoot flavored sake prepared in Example 2 is pale yellow in color and clear and transparent. According to the evaluation, it has a distinct bamboo shoot aroma, a mellow and sweet taste, and a harmonious body (characteristic flavor integration - excellent).

[0059] Example 3 1. Targeted preparation of bamboo shoot flavor precursor liquid 1) Raw material processing: Same as in Example 1.

[0060] 2) Compound enzymatic hydrolysis conversion: Add twice the weight of deionized water to the bamboo shoot pulp and inoculate with compound enzyme preparation for two-step enzymatic hydrolysis; Step 1 (polysaccharide conversion): Adjust the pH to 5.0, add cellulase (150,000 U / g bamboo shoot) and pectinase (205,000 U / g bamboo shoot), and enzymatically hydrolyze at 45℃ for 2.5 hours; Step 2 (Protein / Flavor Precursor Release): Adjust pH to 7.0, add neutral protease (250,000 U / g bamboo shoots), and enzymatically hydrolyze at 55℃ for 1.5 h.

[0061] 3) Enzyme inactivation and solid-liquid separation: After enzymatic hydrolysis, the temperature is rapidly raised to 90℃ and maintained for 10 minutes to inactivate the enzyme. Then, the mixture is centrifuged (5000 rpm, 15 minutes). The resulting supernatant is the bamboo shoot flavor precursor liquid, which is cooled to room temperature for later use.

[0062] 2. Step-by-step co-fermentation 1) Preparation of the main fermentation mash for sake: Following the traditional sake process, refined white rice is steamed, cooled, and then inoculated with Aspergillus oryzae (…). Aspergillus oryzae Prepare rice koji; mix rice koji, steamed rice and water in a mass ratio of 2:10:15 to begin the saccharification stage.

[0063] 2) Stepwise addition and co-fermentation: 18 hours after saccharification starts, bamboo shoot flavor precursor liquid is added to the fermentation mash for the first time; 60 hours after the first addition, the remaining bamboo shoot flavor precursor liquid is added; wherein, each kilogram of polished white rice corresponds to 600g of peeled bamboo shoots to obtain bamboo shoot flavor precursor liquid, and the initial addition amount of bamboo shoot flavor precursor liquid is 60%.

[0064] 3) Temperature-controlled fermentation: The entire fermentation process adopts dynamic temperature control, specifically the temperature control curve of 25℃ (3 days) → 19℃ (7 days) → 15℃ (15 days) for a total of 25 days.

[0065] 3. Post-processing and stability control 1) Filtration and clarification: After fermentation, filter the wine by pressing and add a composite clarifying agent consisting of modified diatomaceous earth (0.4g / L) and chitosan (0.1g / L) to the original wine. Let it stand at 0-4℃ for 7 days to clarify.

[0066] 2) Fine filtration and sterilization: Take the supernatant and pass it through filter cartridges with pore sizes of 1.0μm and 0.45μm for deep filtration in sequence, and finally use a microporous filter membrane with a pore size of 0.22μm for sterilization filtration.

[0067] 3) Stabilization treatment: First, perform instant pasteurization at 70℃ for 30 seconds, then immediately cool and age and store at 4-8℃ in the dark for 30 days to promote the fusion of flavors and physical stability of the sake, thus obtaining bamboo shoot flavored sake.

[0068] The bamboo shoot flavored sake prepared in Example 3 is pale yellow in color and clear and transparent. According to the evaluation, it has a distinct bamboo shoot aroma, a mellow and sweet taste, and a harmonious body (characteristic flavor integration - excellent).

[0069] Example 4 1. Targeted preparation of bamboo shoot flavor precursor liquid 1) Raw material processing: Same as in Example 1.

[0070] 2) Compound enzymatic hydrolysis conversion: Add twice the weight of deionized water to the bamboo shoot pulp and inoculate with compound enzyme preparation for two-step enzymatic hydrolysis; Step 1 (polysaccharide conversion): Adjust the pH to 5.0, add cellulase (150,000 U / g bamboo shoot) and pectinase (205,000 U / g bamboo shoot), and enzymatically hydrolyze at 45℃ for 2.5 hours; Step 2 (Protein / Flavor Precursor Release): Adjust pH to 7.0, add neutral protease (250,000 U / g bamboo shoots), and enzymatically hydrolyze at 55℃ for 1.5 h.

[0071] 3) Enzyme inactivation and solid-liquid separation: After enzymatic hydrolysis, the temperature is rapidly raised to 90℃ and maintained for 10 minutes to inactivate the enzyme. Then, the mixture is centrifuged (5000 rpm, 15 minutes). The resulting supernatant is the bamboo shoot flavor precursor liquid, which is cooled to room temperature for later use.

[0072] 2. Step-by-step co-fermentation 1) Preparation of the main fermentation mash for sake: Following the traditional sake process, refined white rice is steamed, cooled, and then inoculated with Aspergillus oryzae (…). Aspergillus oryzaePrepare rice koji; mix rice koji, steamed rice and water in a mass ratio of 2:10:15 to begin the saccharification stage.

[0073] 2) Stepwise addition and co-fermentation: 18 hours after saccharification starts, bamboo shoot flavor precursor liquid is added to the fermentation mash for the first time; 60 hours after the first addition, the remaining bamboo shoot flavor precursor liquid is added; wherein, each kilogram of polished white rice corresponds to 500g of peeled bamboo shoots to obtain bamboo shoot flavor precursor liquid, and the initial addition amount of bamboo shoot flavor precursor liquid is 60%.

[0074] 3) Temperature-controlled fermentation: The entire fermentation process adopts dynamic temperature control, specifically the temperature control curve of 25℃ (3 days) → 19℃ (7 days) → 15℃ (15 days) for a total of 25 days.

[0075] 3. Post-processing and stability control 1) Filtration and clarification: After fermentation, filter the wine by pressing and add a composite clarifying agent consisting of modified diatomaceous earth (0.4g / L) and chitosan (0.1g / L) to the original wine. Let it stand at 0-4℃ for 7 days to clarify.

[0076] 2) Fine filtration and sterilization: Take the supernatant and pass it through filter cartridges with pore sizes of 1.0μm and 0.45μm for deep filtration in sequence, and finally use a microporous filter membrane with a pore size of 0.22μm for sterilization filtration.

[0077] 3) Stabilization treatment: First, perform instant pasteurization at 70℃ for 30 seconds, then immediately cool and age and store at 4-8℃ in the dark for 30 days to promote the fusion of flavors and physical stability of the sake, thus obtaining bamboo shoot flavored sake.

[0078] The bamboo shoot flavored sake prepared in Example 4 is pale yellow in color and clear and transparent. According to the evaluation, it has a distinct bamboo shoot aroma, a mellow and sweet taste, and a harmonious body (characteristic flavor integration - excellent).

[0079] Comparative Example 1 Traditional soaking method: Sake base spirit was brewed using the method described in Example 1 without adding bamboo shoot flavor precursor liquid (parameters are shown in Table 1).

[0080] Equal amounts of peeled bamboo shoots are cut into thin slices of 3-7mm and then directly soaked in fermented sake base. After soaking for 30 days, the mixture is filtered to obtain bamboo shoot-flavored sake.

[0081] The bamboo shoot flavored sake prepared in Comparative Example 1 had a distinct "raw and green" bamboo shoot taste, which was poorly integrated with the sake body (characteristic flavor integration - poor); slight sedimentation appeared after 2 months of storage.

[0082] Comparative Example 2 Co-fermentation with raw materials: Compared with the brewing method in Example 1, an equal amount of peeled bamboo shoots are added simultaneously with the steamed rice for co-fermentation.

[0083] Comparative Example 2 showed obvious abnormal effervescence and a delayed phase during fermentation, resulting in a cloudy wine with an unpleasant off-flavor (poor integration of characteristic flavors).

[0084] Comparative Example 3 Compared to Example 1, the bamboo shoot flavor precursor liquid was added once 78 hours after saccharification initiation.

[0085] Comparative Example 3 produced a large amount of gas in the early stage of fermentation, and the pressure generated could easily force open the container lid, causing the liquid to spray out. The resulting bamboo shoot flavored sake had an unpleasant rotten smell, ammonia smell, and sulfide smell.

[0086] The physicochemical properties of Examples 1-4, Comparative Examples 1-3, and sake base liquor were measured, and the results are shown in Table 1.

[0087] Table 1 Physicochemical properties of various sakes As can be seen from Table 1, the alcohol content of each sake is similar. The sake produced in the example has a higher sugar content, a higher sugar-acid ratio, and a better taste, which is consistent with the taste. The high amino nitrogen content indicates that the content of amino acids or soluble proteins is high, and the nutritional quality is better.

[0088] The criteria for sensory evaluation are shown in Table 2, as described in Table 1.

[0089] Table 2 Sensory Evaluation Criteria (out of 100) The amino acid content of the bamboo shoot flavored sake prepared in Example 1 was determined, and the results are as follows: the total amino acid content was 193.6 mg / g, of which glutamic acid was 37 mg, aspartic acid was 21.32 mg / g, tyrosine was 16.13 mg / g, leucine was 13.34 mg / g, and the contents of threonine, serine, alanine, valine, etc. all exceeded 10 mg / g.

[0090] The flavor compounds of the bamboo shoot-flavored sake prepared in Example 1 were analyzed using HS-SPME-GCMS, and the results are shown in Table 3.

[0091] Table 3. Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued 1) Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued 2) Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued) Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued from 4) Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued from 5) Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued from 6) Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued from 7) Results of flavor compound analysis of bamboo shoot flavored sake Table 3 (Continued from 8) Results of flavor compound analysis of bamboo shoot flavored sake As shown in Table 3, a total of 121 compounds were detected using gas chromatography-mass spectrometry (GC-MS). The most abundant component in the sample was ethyl hexanoate (12.54%). Esters comprised 36 compounds, accounting for 47.03% of the total, making them the most abundant class. These included ethyl hexanoate, ethyl octanoate, ethyl palmitate, methyl salicylate, and diethyl succinate, which are the main aroma components of the wine. Alcohols comprised 12 compounds, accounting for 22.87% of the total, including linalool, benzyl alcohol, 2-octanol, 1-octanol, and citronellol, which are mostly aromatic alcohols and also the main aroma components of this product. Free acids were almost nonexistent (0.11% of the total), and did not contribute to any unpleasant taste.

[0092] The gas phase-ion migration spectrum of the sake prepared in Example 1 is shown below. Figure 2 The gas phase-ion migration spectrum of the sake prepared in Comparative Example 1 is shown below. Figure 3 .

[0093] from Figure 2 and Figure 3 As can be seen from this, the number of points in the spectrum is significantly higher. Figure 2 more than Figure 3 The number of dots represents the types of volatile flavor compounds detected under the given conditions, and the intensity of the color of the dots represents the relative content of that type of compound. This indicates that the flavor compounds in Example 1 are abundant and of high quality, and the flavor of the sake prepared in Example 1 is superior to that in Comparative Example 1.

[0094] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing bamboo shoot-flavored sake, characterized in that, Includes the following steps: First, the peeled bamboo shoots are blanched, cooled, and crushed to prepare bamboo shoot pulp. Water is added to the bamboo shoot pulp and cellulase and pectinase are used for the first enzymatic hydrolysis, followed by neutral protease for the second enzymatic hydrolysis. Then, the enzymes are inactivated, centrifuged, and the resulting supernatant is the bamboo shoot flavor precursor liquid. In the sake preparation process, 60% to 70% of the total amount of bamboo shoot flavor precursor liquid is added within 12 to 24 hours after all other fermentation raw materials except the bamboo shoot flavor precursor liquid are added. The remaining bamboo shoot flavor precursor liquid is added within 48 to 72 hours after the first addition of the bamboo shoot flavor precursor liquid. After fermentation is completed, the bamboo shoot flavor sake is obtained.

2. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, The blanching temperature is 85-90℃ and the time is 2-3 minutes; and / or, the particle size of the bamboo shoot particles in the bamboo shoot paste is 50-150 μm.

3. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, The mass ratio of bamboo shoot pulp to water is 1:(1.5~2.5).

4. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, The first enzymatic hydrolysis was performed at a pH of 5.0–5.5, a temperature of 45–50°C, and a time of 1.5–2.5 h.

5. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, During the first enzymatic hydrolysis, 100,000 to 150,000 U of cellulase and 200,000 to 300,000 U of pectinase are added per gram of bamboo shoots.

6. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, The second enzymatic hydrolysis was performed at a pH of 6.5–7.0, a temperature of 50–55°C, and a time of 1–1.5 h.

7. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, During the second enzymatic hydrolysis, 150,000 to 250,000 U of the neutral protease were added per gram of bamboo shoot.

8. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, In the sake preparation process, the mass ratio of peeled bamboo shoots used in the bamboo shoot flavor precursor liquid to rice used in fermentation is (0.4-0.6):

1.

9. The method for preparing bamboo shoot-flavored sake according to claim 1, characterized in that, The fermentation temperature of the sake is controlled as follows: 25-28℃ for 0-3 days, 18-22℃ for 4-10 days, and 15-18℃ after 11 days, with a total fermentation time of 25-35 days.

10. A bamboo shoot flavored sake prepared by the method of preparing bamboo shoot flavored sake according to any one of claims 1 to 9.

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