Preparation method of hulless oat vinegar rich in ligustrazine

Abstract

The invention provides a preparation method of hulless oat vinegar rich in ligustrazine, which comprises the following steps: controlling table vinegar to efficiently convert the ligustrazine through a solid-state fermentation process, carrying out alcoholic fermentation by taking high-protein plant hulless oat as a raw material and low-temperature yeast as a saccharifying agent, after the alcoholic fermentation is finished, adding bran and cavings, inoculating kindling materials, and carrying out acetic fermentation to obtain the hulless oat vinegar rich in the ligustrazine. In the acetic acid fermentation stage, the acetoin content is used as the judgment basis of the fermentation period, and after acetic acid fermentation is finished, smoking, vinegar spraying, sterilization, ageing and filling are conducted to obtain a finished product. In the whole vinegar fermentation process, the change rule of acetoin and ligustrazine in each stage is tracked, the acetoin content in the acetic acid fermentation stage is monitored, and the maximum accumulation of ligustrazine in the vinegar is realized through process control. The method is convenient to operate, the technology is easy to master, industrial operation is convenient to achieve, a new way for increasing the ligustrazine content in the table vinegar is provided for table vinegar enterprises, and the economic benefits of the enterprises are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of vinegar, and in particular to a method for preparing oat vinegar rich in ligustrazine. Background Art

[0002] Chuanxiongzine, also known as tetramethylpyrazine (TTMP), belongs to the pyrazine alkaloids and is an important bioactive substance in the traditional Chinese medicine Chuanxiong. It is widely present in many food raw materials, processed foods and alcoholic beverages. As a food flavoring agent, it can give food the aroma of baking, roasting and cocoa, and is widely used in food industrial production. In addition, tetramethylpyrazine also has a variety of clinical medicinal effects, such as lowering blood pressure, promoting blood circulation and removing blood stasis, improving coronary heart disease, dissolving thrombus and inhibiting thrombus, and scavenging free radicals, and it is relatively safe. Some people recommend its use in elderly health care drugs. With the development of detection technology, the discovery of Chuanxiongzine in Zhenjiang vinegar and liquor has further hints for people to fully understand the health care effects of Chuanxiongzine.

[0003] Acetoin (HB) is a precursor of tetramethylpyrazine, has a milky flavor, and is widely used in food, medicine, chemical, tobacco and other industries. In the food industry, acetoin is an important flavor substance in many fermented foods. When used in combination with diacetyl, it can make the wine full-bodied and have a mellow aftertaste. Acetoin is an important flavor substance in vinegar, and its content is an important indicator for controlling the quality of vinegar.

[0004] So far, there are two main mechanisms for the synthesis of pyrazines: (1) For baked goods, pyrazines are flavor substances, mainly formed by sugars and amino acids through the Maillard reaction. (2) The production mechanism of pyrazines synthesized by microorganisms is quite different due to the different fermentation states: for the production of pyrazines by liquid fermentation, microorganisms accumulate 3-hydroxybutanone and add ammonium salts through metabolic regulation to increase the content of tetramethylpyrazine. However, the research on the mechanism of producing tetramethylpyrazine by microbial solid fermentation has been slow.

[0005] As a traditional solid-state fermentation product in my country, tetramethylpyrazine was found in liquor as early as the 1980s when analyzing flavor substances in liquor. However, due to its low content, it did not attract much attention. In 2006, Wu Jianfeng first proposed that tetramethylpyrazine is one of the main functional ingredients in liquor. It is widely present in liquors of different flavors, which has attracted the attention of the industry. At the same time, Wu Jianfeng found that one of the main sources of TTMP in liquor is koji. The change pattern of pyrazine substances in koji is as follows: multi-grain koji is higher than pure wheat koji; high-temperature koji is higher than medium-temperature koji; the content of pyrazine substances in bacterial koji is the highest; the content of pyrazine compounds in yeast koji and white koji is very low. Xu Yan and others from Jiangnan University used a high-yield TTMP functional Bacillus isolated from high-temperature Daqu of Maotai-flavor liquor as the research object, and used substrate addition method and isotope tracing method to track the production process of tetramethylpyrazine, and proposed the view that the main generation pathway of TTMP in Chinese liquor comes from microbial metabolism. Gao Chuanqiang from Taizhou Meilanchun Liquor Factory studied the sources of TTMP in sesame-flavored liquor and preliminarily found that the sources of TTMP were different in different brewing stages of Meilanchun sesame-flavored liquor. In the fermentation stage, TTMP may come from microbial metabolism and Maillard reaction; in the distillation and storage stages, TTMP comes entirely from Maillard reaction. Chinese liquor is a distilled liquor, and the Maillard reaction in the distillation stage has limited effect on increasing the content of ligustrazine in liquor. Therefore, in existing studies, the accumulation of ligustrazine or acetoin is generally increased by strengthening the microorganisms that produce high levels of ligustrazine or acetoin in Daqu, and finally increasing the content of ligustrazine in liquor. Studies have shown that the content of ligustrazine in traditional Chinese liquor ranges from 500 to 6000 μg / L, which is a health function factor of traditional liquor and provides a scientific basis for the concept of "drinking in moderation is good for health".

[0006] In 2004, He Zhengyi first discovered that Zhenjiang vinegar contained ligustrazine. Later, Zhang Shaofei discovered that Shanxi aged vinegar contained ligustrazine. Huang Qun discovered that Xiangxi original vinegar also contained ligustrazine. However, the difference is that, for the formation of pyrazines in my country's vinegar brewing process, most scholars still believe that the Maillard reaction that occurs during heating, boiling and aging of vinegar is the main source of ligustrazine in vinegar. However, there are few reports on controlling the enrichment of ligustrazine in vinegar through fermentation technology during vinegar fermentation, and the regulation mechanism is still unclear.

[0007] Therefore, how to enrich ligustrazine in vinegar through fermentation technology has become an urgent problem to be solved. Summary of the invention

[0008] The present invention is to solve the problem of ligustrazine enrichment in vinegar, and provides a method for preparing naked oats vinegar rich in ligustrazine, wherein high-protein plant naked oats are used as raw materials, low-temperature Daqu is used as a saccharifying agent for alcohol fermentation, after the alcohol fermentation is completed, bran and rice bran are mixed, and then a fire is connected for acetic acid fermentation, and the acetic acid fermentation stage is based on the judgment basis of the fermentation cycle with the acetoin content, and the acetic acid fermentation is completed. Smoked mash, vinegar, sterilization, aging, and filling are performed, which is a finished product; during the whole vinegar fermentation process, the change law of acetoin and ligustrazine at each stage is tracked, the acetoin content at the acetic acid fermentation stage is monitored, and the maximum accumulation of ligustrazine in vinegar is achieved through process control. The present invention is easy to operate, the technology is easy to master, and it is easy to realize industrial operation, and provides a new way to increase the content of ligustrazine in vinegar for vinegar enterprises, and significantly improves the economic benefits of enterprises.

[0009] The present invention provides a method for preparing oat vinegar rich in ligustrazine, comprising the following steps:

[0010] S1, mixing cooked oatmeal powder with Daqu and water in a mass ratio of 10:4:35 and fermenting to obtain oatmeal wine, wherein the non-volatile acidity of the oatmeal wine is 2 degrees, and the non-volatile acid is lactic acid;

[0011] S2, mixing rice husk, rice bran and bran in a mass ratio of 7:3:2.5 to obtain auxiliary materials, and then adding 48% of oat wine in a mass ratio to the auxiliary materials to mix the mash to obtain vinegar mash;

[0012] S3, adding more than 5% of fire to the vinegar mash, starting a fire in one day, turning it over, and the temperature is above 40 degrees; measuring the acetoin content every day, when the acetoin content reaches more than 3000, entering step S4;

[0013] S4, fumigating the mash until the temperature reaches above 80 degrees for 8 hours and above 90 degrees for 24 hours. When the ratio of ligustrazine to acetoin is greater than or equal to 1:1, the fumigation is completed.

[0014] S5, pouring vinegar, pouring vinegar according to step 4, and when the acetic acid acidity is above 5 degrees, pouring vinegar is finished;

[0015] S6, performing aging, measuring the acidity, ligustrazine content, ligustrazine atmospheric volume ratio and acetoin atmospheric volume ratio during the aging process, and ending the aging when the ligustrazine content is greater than or equal to 100 mg / 1kg, and completing a method for preparing naked oats vinegar rich in ligustrazine.

[0016] The method for preparing oat vinegar rich in ligustrazine described in the present invention is, as a preferred embodiment, in step S1, the method for preparing cooked oat flour is: first fry the oat grains until they are 80% cooked and have a moisture content of less than 8%, then grind them into flour and sieve them through a 50-mesh sieve, and finally steam them in a steamer for more than 30 minutes, and break them up and cool them to room temperature.

[0017] The method for preparing oat vinegar rich in ligustrazine of the present invention is, as a preferred embodiment, in step S1, the Daqu includes peas with a mass content of 30% to 40%.

[0018] The method for preparing naked oat vinegar rich in ligustrazine of the present invention is, as a preferred embodiment, in step S1, after the cooked naked oat powder is mixed with Daqu and water, the mixture is raked 24 hours a day for the first three days, and after three days, the mixture is sealed in a vat for fermentation, and the alcohol content when the vat is sealed is 6 degrees; naked oat wine is obtained after 12 days of fermentation, and the alcohol content of the naked oat wine is 8 degrees.

[0019] The method for preparing oat vinegar rich in ligustrazine described in the present invention is, as a preferred embodiment, in step S2, measuring the water content, alcohol content and non-volatile acidity of the vinegar mash, and obtaining the vinegar mash after meeting the standard.

[0020] The method for preparing oat vinegar rich in ligustrazine of the present invention is as a preferred mode, the water content standard of the vinegar mash is 60% to 65%, the alcohol content standard is 4 to 5 degrees, and the non-volatile acidity standard is 0.8 to 1; water can be used to fine-tune the vinegar mash.

[0021] The method for preparing oat vinegar rich in ligustrazine described in the present invention is, as a preferred embodiment, in step S3, the oat vinegar is turned over every day from the 2nd to the 7th day, the temperature is maintained above 40 degrees, the acetoin content gradually increases, and the acetoin content is measured by the meteorological volume method.

[0022] The method for preparing oat vinegar rich in ligustrazine of the present invention is, as a preferred embodiment, in step S4, the fumigation time of the mash is 3 days, and during the fumigation of the mash, the acetoin content gradually decreases and the ligustrazine gradually increases.

[0023] The method for preparing oat vinegar rich in ligustrazine of the present invention is, as a preferred embodiment, in step S5, when the vinegar is produced, the non-volatile acidity is 1 degree, and the ligustrazine content is greater than the acetoin content.

[0024] The method for preparing oat vinegar rich in ligustrazine described in the present invention is, as a preferred embodiment, in step S6, during aging, lactic acid bacteria decompose lactic acid into acetoin, and acetoin is then converted into ligustrazine; the aging time is greater than or equal to 5 months, and during the aging process, the acidity is above 5 degrees, and the atmospheric volume ratio of acetoin and the atmospheric volume ratio of ligustrazine are gradually increased.

[0025] Naked oats are one of the most nutritious grains in the world, and their nutritional value ranks first among cereals. Among cereals, the protein content of naked oats is the highest.

[0026] The protein content of oat flour is 15.6%, while the protein content of wheat flour (standard flour) is 11.2%, that of japonica rice (standard one) is 7.7%, that of cornmeal (yellow) is 8.1%, that of sorghum rice (millet) is 13.0%, that of sorghum rice is 10.4%, and that of millet is 8.0%. In addition, it contains a full range of amino acids, and the eight essential amino acids for the human body are not only high in content but also balanced. The lysine content of oat is more than twice that of rice, wheat flour, cornmeal, sorghum rice, and millet, and about 1.8 times that of sorghum rice. The content of methionine, threonine, phenylalanine, valine, isoleucine, and tryptophan in oat is also higher than that of other cereals. Although the leucine content of oat is slightly lower than that of sorghum rice, millet, and sorghum rice, it is still significantly higher than that of rice, wheat flour, and cornmeal. In particular, the content of histidine, an essential amino acid for children, is also very rich. Zhao Suzhen et al. analyzed the relationship between eight essential amino acids in oats and the total amount of amino acids. The results showed that the total amount of amino acids was significantly positively correlated with leucine, threonine, lysine, phenylalanine, isoleucine and valine, with correlation coefficients of 0.959, 0.952, 0.942, 0.938, 0.847 and 0.826, respectively.

[0027] Therefore, using high-protein oats as raw material and adding pea daqu is beneficial to the enrichment of chuanxiongqin.

[0028] The present invention has the following advantages:

[0029] The present invention uses high-protein plant naked oats as raw materials, and low-temperature daqu including peas as saccharifying agents for alcohol fermentation. After the alcohol fermentation is completed, bran and rice bran are mixed in, and then a fire is connected to carry out acetic acid fermentation. The acetic acid fermentation stage uses the acetoin content as the judgment basis for the fermentation cycle. After the acetic acid fermentation is completed, smoked mash, vinegar is poured, sterilized, aged, and filled to obtain the finished product. During the entire vinegar fermentation process, the variation rules of acetoin and ligustrazine at each stage are tracked, the acetoin content at the acetic acid fermentation stage is monitored, and the maximum accumulation of ligustrazine in vinegar is achieved through process control. The present invention is easy to operate, the technology is easy to master, and it is easy to realize industrial operation, and provides a new way to increase the content of ligustrazine in vinegar for vinegar enterprises, which significantly improves the economic benefits of enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flow chart of a method for preparing oat vinegar rich in ligustrazine. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0032] Example 1

[0033] like Figure 1 As shown, a method for preparing oat vinegar rich in ligustrazine comprises the following steps:

[0034] S1. Select high-protein raw material - oats, use an electromagnetic roasting machine to fry the oats until they are 80% cooked and the moisture content is less than 8%, grind them into powder with a flour mill and sieve through 50 mesh, then use a steamer to steam the material, steam it for 30 minutes after steaming, and beat it until the noodles are no longer sticky and cool down to room temperature;

[0035] Mix one portion of cooked oatmeal powder, 40% Daqu (the staple food of Daqu: wheat (or barley), 60-70% by mass, pea (squash pea) 30%-40% by mass; auxiliary material: 40% of the total rice husk material (raw material ratio becomes mash)), and 3.5 times water, rake every 24 hours for 3 days, seal the vat after 3 days, and the alcohol content after 3 days is 6 degrees; ferment for 12 days, the alcohol content is 8 degrees, the non-volatile acid is 2 degrees, including 2 degrees of lactic acid.

[0036] S2. Mix the mash: Mix 70 kg rice husk, 30 kg rice bran and 25 kg bran, then add 60 kg oat wine and mix well. The moisture content of the mash is about 63%, the alcohol content is about 4.5% and the non-volatile acid is about 0.9. The indicators of the mash can be fine-tuned with water.

[0037] S3. When the fire source is more than 5%, the fire will start in one day and the temperature will be overturned. When the temperature is over 40 degrees, the second day is checked: overturned, over 40 degrees, and the acetylene can be detected; the third day is checked: overturned, over 40 degrees, and the acetylene is over 100; the fourth day is checked: overturned, over 40 degrees, and the acetylene is over 500; the fifth day is checked: overturned, over 40 degrees, and the acetylene is over 1000; the sixth day is checked: overturned, over 40 degrees, and the acetylene is over 2000; the seventh day is checked: overturned, over 40 degrees, and the acetylene is over 3000; turn the mash to smoke;

[0038] S4, the temperature of the smoked mash reaches above 80 degrees in 8 hours and above 90 degrees in 24 hours. For 3 consecutive days, the concentration of ligustrazine is about 1600 and that of acetoin is about 1600, both of which are meteorological volume ratios;

[0039] The dynamic equilibrium of the conversion of acetoin to ligustrazine in the solid state of vinegar mash is broken after pouring vinegar, and a new equilibrium will be established.

[0040] Acetic acid fermentation is the synergistic effect of multiple bacteria co-fermentation. The production of ligustrazine is the result of the interaction of multiple bacteria and multiple substances. First, lactic acid bacteria metabolize lactic acid into acetoin, and acetoin is normally metabolized into acetic acid. However, when acetic acid bacteria ferment, ethanol is converted into acetaldehyde. When the acetaldehyde content is very high, the dynamic balance of acetoin is broken, and acetoin cannot be converted into acetic acid. Acetoin passively accumulates very high. At this time, if there is thermal power, the thermal power of the smoked mash causes acetoin to continuously convert into ligustrazine.

[0041] S5, pour vinegar, pour vinegar according to 4, acetic acid 5 degrees, non-volatile acid 1 degree, ligustrazine 50mg / 1kg, acetoin 45mg / 1kg;

[0042] : After pouring vinegar, the acetic acid content is above 5 degrees. The converted ligustrazine cannot be reversely converted to acetoin, and the diluted acetoin is continuously decomposed by lactic acid bacteria to supplement the acetoin concentration (acetoin is measured to be above 3000). The high acidity prevents acetoin from being converted into acetic acid, and it can only accumulate concentration continuously and convert to ligustrazine under aging conditions.

[0043] S5, aged for more than half a year, ligustrazine 100mg / 1kg, acetoin 100mg / 1kg, acetic acid 5.5 degrees;

[0044] After aging for 1 month, the acidity is 5.0 degrees, ligustrazine is 50mg / 1kg, acetoin is above 100, and ligustrazine is undetectable. (The latter two indicators are atmospheric volume ratios)

[0045] After aging for 2 months, the acidity is 5.0 degrees, ligustrazine is 50mg / 1kg, acetoin is above 500, and ligustrazine is 100. (The latter two indicators are atmospheric volume ratios)

[0046] After aging for 3 months, the acidity is 5.2 degrees, ligustrazine is 50mg / 1kg, acetoin is more than 1000, and ligustrazine is 500. (The latter two indicators are atmospheric volume ratios)

[0047] After aging for 4 months, the acidity is 5.4 degrees, ligustrazine is 60mg / 1kg, acetoin is more than 2000, and ligustrazine is 1000. (The latter two indicators are atmospheric volume ratios)

[0048] After aging for 5 months, the acidity is 5.5 degrees, ligustrazine is 80mg / 1kg, acetoin is more than 3000, and ligustrazine is 2000. (The latter two indicators are the atmospheric volume ratio)

[0049] After aging for 6 months, the acidity is 5.6 degrees, ligustrazine is 100mg / 1kg, acetoin is more than 3000, and ligustrazine is 2500. (The latter two indicators are atmospheric volume ratios)

[0050] During the aging stage, the acetic acid content is above 5 degrees, and acetoin has lost the power to convert into acetic acid, while lactic acid bacteria continue to decompose lactic acid into acetoin. As the concentration of acetoin increases, acetoin also slowly converts into ligustrazine.

[0051] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing oat vinegar rich in ligustrazine, characterized in that: The following steps are involved: S1, mixing cooked naked oat flour with Daqu and water in a mass ratio of 10:4:35 and fermenting to obtain naked oat wine, wherein the naked oat wine has a non-volatile acidity of 2 degrees, and the non-volatile acid is lactic acid; S2, mixing rice husk, rice bran and bran in a mass ratio of 7:3:2.5 to obtain auxiliary materials, and then adding 48% of the naked oat wine in a mass ratio to the auxiliary materials to mix the mash to obtain vinegar mash; S3, adding more than 5% of fire to the vinegar mash, starting a fire in one day, turning it over, and the temperature is above 40 degrees; measuring the acetoin content every day, and when the acetoin content reaches more than 3000, entering step S4; S4, smoke the mash until the temperature reaches above 80 degrees for 8 hours and above 90 degrees for 24 hours. When the ratio of ligustrazine to acetoin is greater than or equal to 1:1, the smoked mash is finished; S5, pouring vinegar, pouring vinegar according to step 4, and when the acetic acid acidity is above 5 degrees, pouring vinegar is finished; S6, performing aging, measuring the acidity, ligustrazine content, ligustrazine atmospheric volume ratio and acetoin atmospheric volume ratio during the aging process, and ending the aging when the ligustrazine content is greater than or equal to 100 mg / 1kg, and completing a method for preparing naked oats vinegar rich in ligustrazine.

2. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S1, the method for preparing cooked oat flour is as follows: first, the oat grains are fried until 80% cooked and the moisture content is less than 8%, then ground into flour and sieved through a 50-mesh sieve, and finally steamed in a steamer for more than 30 minutes, and then crushed and cooled to room temperature.

3. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S1, the Daqu comprises peas in an amount of 30% to 40% by mass.

4. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S1, after the cooked oatmeal powder is mixed with Daqu and water, the oatmeal powder is raked 24 hours a day for the first three days, and the oatmeal is sealed for fermentation after three days, and the alcohol content when the oatmeal is sealed is 6 degrees; the oatmeal wine is obtained after 12 days of fermentation, and the alcohol content of the oatmeal wine is 8 degrees.

5. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S2, the moisture content, alcohol content and non-volatile acidity of the vinegar-grown mash are measured, and the vinegar-grown mash is obtained when the moisture content, alcohol content and non-volatile acidity of the vinegar-grown mash meet the standard.

6. The method for preparing oat vinegar rich in ligustrazine according to claim 5, characterized in that: The moisture content standard of the vinegar mash is 60% to 65%, the alcohol content standard is 4 to 5 degrees, and the non-volatile acidity standard is 0.8 to 1; water can be used to fine-tune the vinegar mash.

7. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S3, the soil is turned over every day from the 2nd to the 7th day, the temperature is kept above 40 degrees, and the acetoin content gradually increases. The acetoin content is measured by the meteorological volume method.

8. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S4, the mash is smoked for 3 days. During the smoked mash, the acetoin content gradually decreases and the ligustrazine content gradually increases.

9. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S5, when vinegar is produced, the non-volatile acidity is 1 degree, and the chuanxiongzine content is greater than the acetoin content.

10. The method for preparing oat vinegar rich in ligustrazine according to claim 1, characterized in that: In step S6, during aging, the lactic acid bacteria decompose lactic acid into acetoin, and the acetoin is converted into chuanxiongzine; the aging time is greater than or equal to 5 months, and during the aging process, the acidity is above 5 degrees, and the atmospheric volume ratio of acetoin and the atmospheric volume ratio of chuanxiongzine both gradually increase.

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