Method for brewing Guizhou sun-dried vinegar by using high-temperature Daqu to ferment wine mash

Abstract

The present application relates to the technical field of vinegar brewing, and discloses a method for brewing Guizhou sun-dried vinegar by using high-temperature Daqu to ferment wine mash, which relies on the unique microbial ecological advantages of the Chishui River basin, and comprises the following steps: firstly, pretreating glutinous rice, then adding the pretreated glutinous rice into local sauce-flavor high-temperature Daqu to prepare wine mash through alcohol fermentation; secondly, mixing the wine mash with bran and chaff at a ratio of 3L:1kg:0.125kg, and inoculating the mixture with traditional sun-dried vinegar seed koji; thirdly, completing vinegar koji fermentation by following the solid-state layered fermentation process of vinegar koji; and finally, obtaining finished sun-dried vinegar through three sets of circulating vinegar spraying, pasteurization, daily sunning and night airing aging. The present application optimizes the flavor basis of wine mash from the source, increases the total content of esters in vinegar koji by 22.1% and the total content of acids by 28.1%, introduces three kinds of volatile flavor substances unique to high-temperature Daqu, shortens the sunning aging period from 1-3 years to 6-8 months, and forms a differentiated flavor with both sauce-flavor heritage and sun-dried vinegar original flavor, thereby providing a new path for the quality upgrading and characteristic development of Guizhou sun-dried vinegar industry.

Description

Technical Field

[0001] This invention relates to the field of vinegar brewing technology, specifically to a method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash. Background Technology

[0002] Guizhou sun-dried vinegar, with Chishui sun-dried vinegar as its core representative, is produced in the same core brewing area of ​​the Chishui River basin as Maotai liquor. Its brewing history can be traced back to the Wanli period of the Ming Dynasty. After salt merchants from Sichuan brought Sichuan vinegar-making techniques to Guizhou, it gradually evolved by integrating with the local climate, water source, and microbial ecology, and has a history of more than 400 years. In 2021, the brewing technique of Chishui sun-dried vinegar was listed as a national intangible cultural heritage representative project, and is a landmark product of Guizhou's distinctive fermented foods.

[0003] Traditional Guizhou sun-dried vinegar uses high-quality glutinous rice and regular rice from the Chishui River basin as its main raw materials, employing locally made wheat koji as a saccharification and fermentation agent. After processes such as steaming, alcoholic fermentation, solid-state layered fermentation, and vinegar extraction, the core process relies on natural aging in open-air ceramic jars under the sun and dew for 1-3 years, with some high-end products aged for over 5 years. This long-term sun-drying aging process causes complex Maillard and esterification reactions in the vinegar, resulting in a unique quality characterized by a bright reddish-brown color, a mellow and rich acidity, a blend of soy sauce and ester aromas, and a long shelf life that improves with age, making it highly popular among consumers in Southwest China.

[0004] However, the development of Guizhou's sun-dried vinegar industry currently faces three major bottlenecks: First, the microbial community structure of traditional wheat koji is relatively simple, mainly consisting of Aspergillus and brewing yeast, with limited ester and aroma production capabilities, resulting in a thin basic flavor in the vinegar mash. It is necessary to rely on long-term sun-drying and aging to compensate for the lack of flavor, which leads to long production cycles, large capital occupation, and difficulty in rapidly increasing production capacity. Second, product homogenization is serious. The vast majority of enterprises use traditional wheat koji technology, resulting in minimal differences in the flavor of finished products and a lack of distinctive high-end products. Third, the unique advantages of the microbial resources in the Chishui River Basin have not been fully utilized, especially the mature high-temperature koji industry and rich aroma-producing microbial system in the region, which have not yet been effectively integrated with sun-dried vinegar brewing technology.

[0005] Existing technological improvements for Guizhou sun-dried vinegar mainly focus on optimizing the aging process, upgrading automated equipment, and selecting single-function strains of microorganisms. For example, artificial temperature control can accelerate the aging reaction, and mechanized turning of the mash can reduce labor intensity. However, these improvements have not fundamentally changed the flavor base of the mash and cannot fundamentally solve the problems of long production cycles and homogenized flavors in traditional processes. Summary of the Invention

[0006] The present invention aims to provide a method for brewing Guizhou sun-dried vinegar using high-temperature fermentation mash, in order to solve the problems of long production cycle and homogeneous flavor in traditional processes.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash, comprising the following steps: After washing, soaking, steaming and cooling the glutinous rice, it is added to the high-temperature koji for alcoholic fermentation to obtain high-temperature koji mash. High-temperature Daqu liquor mash is mixed evenly with wheat bran and rice husks, inoculated with traditional Guizhou sun-dried vinegar mash, and piled up. The mash is then fermented in stages according to the layered fermentation process of vinegar mash to obtain mature vinegar mash. The mature vinegar mash undergoes three cycles of vinegar extraction. After collecting the first vinegar, it is pasteurized and aged by sun and dew in sequence to obtain the finished Guizhou sun-dried vinegar.

[0008] Preferably, as an improvement, the volume-to-mass ratio of the high-temperature Daqu liquor mash to wheat bran is 3L:1kg, and the volume-to-mass ratio of the high-temperature Daqu liquor mash to total rice husks is 6L:0.75kg.

[0009] Preferably, as an improvement, the solid-state layered fermentation turning process is as follows: 12 hours after inoculation, the seed mash is turned over to form a top layer; 24 hours later, the first layer of mash with raw material is turned over thinly; 36 hours later, the turning depth is two fingers deep; 48 hours later, the turning depth is half a palm deep; 60 hours later, the turning depth is half a palm deep; 72 hours later, the turning depth is half a finger deep; 84 hours later, the bottom layer is exposed; and 96 hours and 108 hours later, a full turning is performed respectively.

[0010] Preferably, as an improvement, after the alcoholic fermentation is completed, the alcohol content of the high-temperature Daqu liquor mash is controlled at 9.2%-9.5% vol.

[0011] Preferably, as an improvement, during the solid-state fermentation process, the maximum temperature of the vinegar mash is controlled at 43℃-46℃, and the pH value of the vinegar mash at the end of fermentation is 3.6-3.9.

[0012] Preferably, as an improvement, in the initial stage of solid-state fermentation, the moisture content of the vinegar mash is controlled at 67%-70%, and after fermentation for 2-3 days, the moisture content drops to 63%-66% and then tends to stabilize.

[0013] Preferably, as an improvement, the total duration of the solid-state fermentation is 6-7 days.

[0014] Preferably, as an improvement, the finished Guizhou sun-dried vinegar contains three volatile flavor substances unique to high-temperature koji for soy sauce aroma: diethyl azelaate, 3-methylvaleric acid, and 2-octanone.

[0015] The beneficial effects of this plan are: 1. It makes full use of the advantages of regional resources and applies the characteristic high-temperature koji of the Chishui River Basin to the brewing of sun-dried vinegar, realizing the cross-border utilization of local microbial resources and forming a sun-dried vinegar brewing technology with Guizhou regional characteristics.

[0016] 2. Enhancing the flavor base from the source: The complex microbial community of high-temperature Daqu makes the mash contain richer aroma precursors. The total ester content of vinegar mash is increased by 22.1% and the total acid content is increased by 28.1% compared with the traditional wheat koji process, which greatly enhances the basic flavor of sun-dried vinegar.

[0017] 3. Significantly shortens the production cycle. Due to the richer basic flavor of the vinegar mash, the aging cycle of sun-drying and dew-drying can be shortened from the traditional 1-3 years to 6-8 months, and the quality of the finished product reaches the level of traditional aging process of more than 1 year, effectively reducing production costs.

[0018] 4. To create differentiated flavor characteristics, the finished sun-dried vinegar not only retains the mellow and rich sour taste of traditional sun-dried vinegar, but also introduces three volatile flavor substances unique to high-temperature Daqu: diethyl azelaate, 3-methylvaleric acid, and 2-octanone, forming a unique medicinal aroma, soy sauce aroma, and ketone aroma, thus solving the problem of product homogenization.

[0019] 5. It has strong process compatibility. The basic fermentation indicators of high-temperature Daqu liquor mash and traditional wheat liquor mash show the same trend. It can be directly adapted to the existing production equipment and process flow of Guizhou sun-dried vinegar without the need for large-scale technical transformation, which makes it easy for enterprises to quickly promote and apply it. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the brewing process of a method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash according to an embodiment of the present invention. Figure 2 This is a comparison curve of the fermentation temperature of vinegar mash in the present invention and the traditional wheat koji process; Figure 3 This is a curve comparing the pH changes of vinegar mash in the present invention and the traditional wheat koji process; Figure 4 This is a comparison chart of the changes in moisture content of vinegar mash in the present invention and the traditional wheat koji process; Figure 5 This is a comparison chart of the changes in total acid content of vinegar mash in the present invention and the traditional wheat koji process; Figure 6 This is a comparison chart of the changes in lactic acid content in vinegar mash produced by the present invention and by the traditional wheat koji process; Figure 7 This is a comparison chart of the changes in acetic acid content in vinegar mash produced by the present invention and by the traditional wheat koji process; Figure 8 This is a comparison chart of the changes in alcohol content in vinegar mash produced by the present invention and by the traditional wheat koji process; Figure 9 This is a comparison chart of the changes in the content of ester compounds in the acetic acid mash produced by the present invention and by the traditional wheat koji process; Figure 10This is a comparison chart showing the changes in the content of acidic compounds in the vinegar mash produced by the present invention and the traditional wheat koji process; Figure 11 This is a comparison chart of the changes in aldehyde content in acetic acid mash produced by the present invention and by the traditional wheat koji process; Figure 12 This is a comparison chart of the changes in the content of ketone compounds in the acetic mash produced by the present invention and the traditional wheat koji process; Figure 13 This is a comparison chart showing the changes in the content of phenolic compounds in vinegar mash produced by the present invention and by the traditional wheat koji process. Detailed Implementation

[0021] The following detailed description illustrates the specific implementation method: Example I. A method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash. The overall process flow is as follows Figure 1 As shown, the specific operation process is as follows: First, select plump, mold-free, high-quality glutinous rice from Chishui as raw material. Wash the glutinous rice 2-3 times in clean water to remove impurities and dust, then soak it for 14 hours until the glutinous rice has fully absorbed water, can be easily crushed by fingers, and has no hard core. Drain the soaked glutinous rice and steam it in a steamer over high heat for 25 minutes, until the glutinous rice is fully cooked, has no white core, and is not sticky. After removing it, spread it evenly on a clean bamboo mat and cool it to 28℃ for later use. Add high-temperature koji (a type of starter culture) to the cooled glutinous rice at a ratio of 10:1 (glutinous rice to koji by weight). Stir well and transfer it to a sterile fermentation tank. Seal the tank and place it in a constant temperature environment of 30℃ for alcoholic fermentation. Stir once a day during fermentation. Stop fermentation after 7 days, filter to remove residue, and obtain high-temperature koji mash. Testing revealed that the alcohol content of the high-temperature Daqu liquor mash in this embodiment was 9.4% vol, while the alcohol content of the traditional wheat liquor mash under the same conditions was 9.2% vol. The difference between the two was minimal, ensuring complete compatibility with the subsequent vinegar mash fermentation process.

[0022] Take 6L of the above-mentioned high-temperature Daqu liquor mash, mix it evenly with 2kg of wheat bran and 500g of rice husk in a mixer, and spread 100g of rice husk evenly at the bottom of the fermentation tank as a base. Transfer the mixed material to the fermentation tank, inoculate it with 100g of Guizhou sun-dried vinegar traditional seed mash, and pile it into a cone shape. Add the remaining 150g of rice husk in small amounts every day during the subsequent fermentation process and cover the tank. 12 hours after inoculating the seed mash, observe that the temperature of the vinegar mash has not risen significantly, and then perform the turning and piling of the seed mash. After 24 hours, turn the first layer of mash with raw material in a thin layer. After 36 hours, turn the mash to a depth of about two fingers. After 48 hours, turn the mash to a depth of about half a palm. After 60 hours, turn the mash to a depth of only the bottom layer of mash, about half a palm. After 72 hours, turn the mash to a depth of only the bottom layer of mash, about half a finger. After 84 hours, turn the bottom layer of vinegar mash to expose the bottom. After 96 hours and 108 hours, perform a full turning operation on all the vinegar mash.

[0023] During fermentation, the temperature of the vinegar mash was monitored every 12 hours, and the pH value, moisture content, and total acid content were monitored daily. The changes in various basic physicochemical indicators are as follows: Temperature changes such as Figure 2 As shown: at 0h, the temperature of the high-temperature Daqu vinegar mash was 25.2℃, and that of the wheat koji vinegar mash was 24.8℃; at 24h, they rose to 38.5℃ and 36.7℃ respectively; at 48h, they reached their peak, with the high-temperature Daqu vinegar mash at 43.8℃ and the wheat koji vinegar mash at 42.1℃; at 72h, they dropped to 39.2℃ and 45.1℃ respectively; at the end of fermentation at 144h (6 days), the temperature of the high-temperature Daqu vinegar mash dropped to 30.9℃, and that of the wheat koji vinegar mash dropped to 35.1℃.

[0024] pH changes as follows Figure 3 As shown: at 0 days, the pH value of high-temperature Daqu vinegar mash was 4.58, and that of wheat koji vinegar mash was 4.78; at 1 day, they were 4.32 and 4.51 respectively; at 2 days, they were 4.08 and 4.35 respectively; at 3 days, they were 4.00 and 4.27 respectively; at 4 days, they were 3.95 and 4.02 respectively; at 5 days, they were 3.89 and 3.81 respectively; at the end of fermentation on 6 days, the pH value of high-temperature Daqu vinegar mash was 3.83, and that of wheat koji vinegar mash was 3.66.

[0025] Changes in water content, such as Figure 4 As shown: at 0 days, the moisture content of high-temperature Daqu vinegar mash was 67.32%, and that of wheat Daqu vinegar mash was 69.75%; at 1 day, they were 66.15% and 65.82% respectively; at 2 days, they were 65.78% and 63.91% respectively; at 3 days, they were 65.35% and 64.23% respectively; the moisture content remained basically stable from 4 to 6 days, with fluctuations not exceeding 0.5%.

[0026] Changes in total acid content as follows Figure 5 As shown: at day 0, the total acidity of high-temperature Daqu vinegar mash was 1.7g / 100g dry mash, and that of wheat koji vinegar mash was 2.15g / 100g dry mash; at day 1, the values ​​were 1.92g / 100g dry mash and 2.37g / 100g dry mash, respectively; at day 2, the values ​​were 2.35g / 100g dry mash and 2.81g / 100g dry mash, respectively; and at day 3, the values ​​were 2.89g / 100g dry mash and 3.24g / 100g dry mash, respectively. At 4 days, the total acid content was 3.36g / 100g dry mash and 3.58g / 100g dry mash, respectively; at 5 days, it was 3.71g / 100g dry mash and 3.80g / 100g dry mash, respectively; at 6 days, it was 4.02g / 100g dry mash and 3.52g / 100g dry mash, respectively; at 7 days, the total acid content of high-temperature Daqu vinegar mash still rose to 4.15g / 100g dry mash, while that of wheat koji vinegar mash dropped to 3.0g / 100g dry mash.

[0027] Changes in lactic acid content as follows Figure 6As shown: at day 0, the lactic acid content of high-temperature Daqu vinegar mash was 0.84 g / 100 g, and that of wheat koji vinegar mash was 1.26 g / 100 g; at day 1, they were 0.67 g / 100 g and 0.42 g / 100 g respectively; at day 2, they dropped to the lowest values ​​of 0.54 g / 100 g and 0.18 g / 100 g respectively; at day 3, they were 0.61 g / 100 g and 0.25 g / 100 g respectively; at day 4, they were 0.73 g / 100 g and 0.51 g / 100 g respectively; at day 5, they were 0.89 g / 100 g and 0.47 g / 100 g respectively; at the end of fermentation on day 6, the lactic acid content of high-temperature Daqu vinegar mash was 0.92 g / 100 g, and that of wheat koji vinegar mash was 0.49 g / 100 g.

[0028] Changes in acetic acid content, such as Figure 7 As shown: at day 0, the acetic acid content in the high-temperature Daqu vinegar mash was 1.15 g / 100 g, and in the wheat koji vinegar mash it was 1.39 g / 100 g; at day 1, they were 2.37 g / 100 g and 2.12 g / 100 g respectively; at day 2, they were 4.52 g / 100 g and 3.86 g / 100 g respectively; at day 3, they were 6.78 g / 100 g and 5.43 g / 100 g respectively; at day 4, they were 8.91 g / 100 g and 7.25 g / 100 g respectively; at day 5, they were 10.26 g / 100 g and 8.57 g / 100 g respectively; at the end of fermentation on day 6, the acetic acid content in the high-temperature Daqu vinegar mash was 11.43 g / 100 g, and in the wheat koji vinegar mash it was 9.68 g / 100 g.

[0029] The total fermentation time is 6 days, resulting in mature vinegar mash. The mature vinegar mash is then subjected to a three-stage leaching process. First, the mature vinegar mash is soaked in second vinegar for 5 hours to extract the first vinegar. Then, third vinegar is added and soaked for 2.5 hours to extract the second vinegar. Finally, water is added and soaked for 1.5 hours to extract the third vinegar. The collected first vinegars are combined and then pasteurized at 68°C for 18 minutes. The mixture is then placed in sterile ceramic jars and aged in an open-air drying yard for 6 months under the sun and dew to obtain the finished Guizhou sun-dried vinegar.

[0030] The Guizhou sun-dried vinegar brewed using the method described in this embodiment was analyzed by gas chromatography-mass spectrometry combined with solid-phase microextraction. A total of 64 volatile flavor compounds were detected, including 29 esters, 15 alcohols, 7 acids, 5 ketones, 4 aldehydes, and 4 phenols. The content variations of each volatile flavor compound are as follows: Changes in alcohol content, such as Figure 8As shown: In the early stage of fermentation (0d), the total alcohol content of high-temperature Daqu vinegar mash was 6604.11μg / 100g dry mash, and that of wheat koji vinegar mash was 6055.84μg / 100g dry mash; at the end of fermentation (6d), the total alcohol content of high-temperature Daqu vinegar mash decreased to 2224.78μg / 100g dry mash, and that of wheat koji vinegar mash decreased to 1917.52μg / 100g dry mash, while that of high-temperature Daqu vinegar mash was 307.26μg / 100g dry mash higher. Among them, phenylethanol is the most abundant alcohol, with 1165.62 μg / 100g dry mash in high-temperature Daqu vinegar mash and 1378.72 μg / 100g dry mash in wheat koji vinegar mash; isoamyl alcohol content is 553.48 μg / 100g dry mash in high-temperature Daqu vinegar mash and 226.44 μg / 100g dry mash in wheat koji vinegar mash; ethanol content is 56.91 μg / 100g dry mash in high-temperature Daqu vinegar mash and 73.44 μg / 100g dry mash in wheat koji vinegar mash.

[0031] Changes in ester compound content, such as Figure 9 As shown: In the early stage of fermentation (0d), the total ester content of high-temperature Daqu vinegar mash was 3567.24μg / 100g dry mash, and that of wheat koji vinegar mash was 1289.57μg / 100g dry mash; at the end of fermentation (6d), the total ester content of high-temperature Daqu vinegar mash increased to 8351.23μg / 100g dry mash, and that of wheat koji vinegar mash increased to 6839.15μg / 100g dry mash, with the high-temperature Daqu vinegar mash being 1512.08μg / 100g dry mash higher. Among them, ethyl acetate had the highest content, at 4014.25 μg / 100g dry mash in high-temperature Daqu vinegar mash and 1741.58 μg / 100g dry mash in wheat koji vinegar mash; phenethyl acetate content was 1465.82 μg / 100g dry mash in high-temperature Daqu vinegar mash and 1736.69 μg / 100g dry mash in wheat koji vinegar mash; diethyl azelaate was only detected in high-temperature Daqu vinegar mash, with a content of 5.11 μg / 100g dry mash.

[0032] Changes in the content of acid compounds, such as Figure 10 As shown: In the early stage of fermentation (0d), the total acid content of high-temperature Daqu vinegar mash was 264.94μg / 100g dry mash, and that of wheat koji vinegar mash was 31.33μg / 100g dry mash; at the end of fermentation (6d), the total acid content of high-temperature Daqu vinegar mash increased to 3672.37μg / 100g dry mash, and that of wheat koji vinegar mash increased to 2866.65μg / 100g dry mash, with the high-temperature Daqu vinegar mash being 805.72μg / 100g higher than that of dry mash. Acetic acid had the highest content, at 3578.20 μg / 100g dry mash in high-temperature Daqu vinegar mash and 2271.04 μg / 100g dry mash in wheat koji vinegar mash; 3-methylvaleric acid was only detected in high-temperature Daqu vinegar mash, at 36.58 μg / 100g dry mash, and has a unique herbal aroma; isovaleric acid was only detected in wheat koji vinegar mash, at 58.50 μg / 100g dry mash, and has a fruity flavor.

[0033] Changes in aldehyde content, such as Figure 11 As shown: In the early stage of fermentation (0d), the total aldehyde content of high-temperature Daqu vinegar mash was 205.35μg / 100g dry mash, and that of wheat koji vinegar mash was 157.63μg / 100g dry mash; at the end of fermentation (6d), the total aldehyde content of high-temperature Daqu vinegar mash decreased to 45.97μg / 100g dry mash, and that of wheat koji vinegar mash decreased to 111.68μg / 100g dry mash, with the wheat koji vinegar mash being 65.71μg / 100g higher than that of dry mash. Among them, the phenylacetaldehyde content of high-temperature Daqu vinegar mash is 30.20 μg / 100g dry mash, and that of wheat koji vinegar mash is 40.67 μg / 100g dry mash; the trans-2,4-decadienal content of high-temperature Daqu vinegar mash is 10.65 μg / 100g dry mash, and that of wheat koji vinegar mash is 3.11 μg / 100g dry mash, and it has a chicken fat aroma.

[0034] Changes in ketone content, such as Figure 12 As shown: In the early stage of fermentation (0d), the total ketone content of high-temperature Daqu vinegar mash was 52.11μg / 100g dry mash, and that of wheat koji vinegar mash was 15.66μg / 100g dry mash; at the end of fermentation (6d), the total ketone content of high-temperature Daqu vinegar mash decreased to 41.56μg / 100g dry mash, while that of wheat koji vinegar mash increased to 29.43μg / 100g dry mash, with the high-temperature Daqu vinegar mash being 12.13μg / 100g higher than that of dry mash. Among them, 2-octanone was only detected in high-temperature Daqu vinegar mash, with a content of 5.99 μg / 100g dry mash, and has a musty aroma, ketone aroma, and flavors of milk, cheese, and mushroom; the content of 3-hydroxy-2-butanone in high-temperature Daqu vinegar mash was 14.73 μg / 100g dry mash, and in wheat Daqu vinegar mash it was 11.94 μg / 100g dry mash, and has a buttery flavor.

[0035] Changes in phenolic compound content, such as Figure 13 As shown: In the initial stage of fermentation (0d), the total phenolic content of high-temperature Daqu vinegar mash was 51.65μg / 100g dry mash, and that of wheat koji vinegar mash was 20.96μg / 100g dry mash; at the end of fermentation (6d), the total phenolic content of high-temperature Daqu vinegar mash decreased to 10.04μg / 100g dry mash, while that of wheat koji vinegar mash increased to 38.15μg / 100g dry mash, exceeding that of wheat koji vinegar mash by 28.11μg / 100g dry mash. Among these, the phenol content was 2.99μg / 100g dry mash in high-temperature Daqu vinegar mash and 34.24μg / 100g dry mash in wheat koji vinegar mash.

[0036] II. Determination and analysis of volatile flavor components and sensory evaluation The vinegar mash produced by microbial fermentation using high-temperature Daqu and wheat koji blocks was sampled, and the types and contents of volatile flavor compounds during the fermentation stage were detected and analyzed using gas chromatography-mass spectrometry combined with solid-phase microextraction. The CAS numbers were searched and analyzed using the iChem.net website to determine the types and characteristics of the compounds. Six major volatile flavor compounds were detected: alcohols, esters, acids, aldehydes, ketones, and phenols. Among them, there were 29 esters, 15 alcohols, 7 acids, 5 ketones, 4 phenols, and 4 aldehydes, for a total of 64 volatile flavor compounds.

[0037]

[0038] Table 1. Volatile flavor compounds of two types of vinegar mash during fermentation. Table 1 shows that in high-temperature Daqu vinegar mash, alcohols were most abundant on day 0, followed by esters, acids, and aldehydes, with phenols being the least abundant. After fermentation, on day 6 (the end of day), esters were most abundant, followed by acids, alcohols, and aldehydes, with phenols still being the least abundant. In wheat Daqu vinegar mash, alcohols were most abundant on day 0, followed by esters, acids, and aldehydes, with ketones being the least abundant. After fermentation, on day 6 (the end of day), esters were most abundant, followed by acids, alcohols, and aldehydes, with phenols being the least abundant. Diethyl azelaate, 3-methylvaleric acid, and 2-octanone were only detected in high-temperature Daqu vinegar mash, while isovaleric acid was only detected in wheat Daqu vinegar mash. Other volatile components were detected in both types of vinegar mash at the beginning or end of fermentation.

[0039]

[0040] Table 2 Sensory Evaluation Standards for Vinegar Made from High-Temperature Daqu Liquor Mash and Vinegar Made from Wheat Flour Mash The evaluation results show that the finished product of this embodiment is reddish-brown and bright with a glossy appearance. It is clear and free of suspended matter and sediment. The aroma is mellow and rich, with prominent ester aroma and a faint aroma of soy sauce and medicine. The acidity is mild and harmonious, with a slight sweetness. There are no unpleasant off-flavors. The overall sensory quality is significantly better than that of products aged for 6 months using the traditional wheat koji process and is comparable to that of products aged for 12 months using the traditional wheat koji process.

[0041] In summary, this embodiment fully verifies the feasibility and superiority of the method of brewing Guizhou sun-dried vinegar using high-temperature fermentation mash with soy sauce aroma. Based on complete adaptation to the existing production equipment and process flow of Guizhou sun-dried vinegar, this method significantly improves the ester and acid production capacity of vinegar mash through optimization of the microorganisms and flavor base of the source mash. It introduces three unique volatile flavor substances with regional characteristics, enabling the finished sun-dried vinegar to achieve the sensory quality of traditional wheat koji aging process of 12 months under only 6 months of sun-drying and night-dew aging. It effectively solves the industry pain points of long production cycle, large capital occupation and serious product homogenization of traditional Guizhou sun-dried vinegar, and provides practical technical support for the characteristic and high-end development of Guizhou sun-dried vinegar industry, with broad prospects for industrial application.

[0042] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash, characterized in that: Includes the following steps: After washing, soaking, steaming and cooling the glutinous rice, it is added to the high-temperature koji for alcoholic fermentation to obtain high-temperature koji mash. The high-temperature Daqu liquor mash is mixed evenly with wheat bran and rice husks, inoculated with traditional Guizhou sun-dried vinegar mash, and piled up. The mash is then fermented in stages according to the solid-state layered fermentation process of vinegar mash to obtain mature vinegar mash. The mature vinegar mash undergoes three cycles of vinegar extraction. After collecting the first vinegar, it is pasteurized and aged by sun and dew in sequence to obtain the finished Guizhou sun-dried vinegar.

2. The method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash as described in claim 1, characterized in that: The volume-to-mass ratio of the high-temperature Daqu liquor mash to wheat bran is 3L:1kg, and the volume-to-mass ratio of the high-temperature Daqu liquor mash to total rice husks is 6L:0.75kg.

3. The method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash as described in claim 2, characterized in that: The solid-state layered fermentation turning process is as follows: 12 hours after inoculation, the seed mash is turned over and piled up; 24 hours later, the first layer of mash with raw material is turned over thinly; 36 hours later, the turning depth is two fingers deep; 48 hours later, the turning depth is half a palm deep; 60 hours later, the turning depth is half a palm deep; 72 hours later, the turning depth is half a finger deep; 84 hours later, the bottom layer is exposed; and 96 hours and 108 hours later, a full turning is performed respectively.

4. The method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash as described in claim 3, characterized in that: After the alcoholic fermentation is completed, the alcohol content of the high-temperature Daqu liquor mash is controlled at 9.2%-9.5% vol.

5. The method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash according to claim 4, characterized in that: During the solid-state fermentation process, the maximum temperature of the vinegar mash is controlled at 43℃-46℃, and the pH value of the vinegar mash at the end of fermentation is 3.6-3.

9.

6. The method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash according to claim 5, characterized in that: In the initial stage of solid-state fermentation, the moisture content of the vinegar mash is controlled at 67%-70%, and after fermentation for 2-3 days, the moisture content drops to 63%-66% and then tends to stabilize.

7. A method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash according to claim 6, characterized in that: The total duration of the solid-state fermentation is 6-7 days.

8. A method for brewing Guizhou sun-dried vinegar using high-temperature Daqu fermentation mash according to claim 7, characterized in that: The finished Guizhou sun-dried vinegar contains three volatile flavor compounds unique to high-temperature koji for soy sauce aroma: diethyl azelaate, 3-methylvaleric acid, and 2-octanone.

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