Method for increasing non-volatile acid content of glutinous rice vinegar

Abstract

The application discloses a method for increasing non-volatile acid content of glutinous rice vinegar, and relates to the technical field of vinegar brewing. The glutinous rice is used as raw material to prepare glutinous rice vinegar through alcohol fermentation and acetic acid fermentation processes. The glutinous rice vinegar not only contains rich nutritional components, but also has soft acid gas, long aftertaste, high quality, total acid content (calculated by acetic acid) greater than 5.3 g / 100mL, and non-volatile acid content (calculated by lactic acid) greater than 1.5 g / 100mL, which meets the requirements of GB 18187-2000 "Brewed Vinegar". The unique taste and flavor of the glutinous rice vinegar are beneficial to improving market competitiveness of the product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vinegar brewing, in particular to a method for increasing the non-volatile acid content of glutinous rice vinegar. BACKGROUND

[0002] Glutinous rice vinegar is made from glutinous rice as the main raw material through fermentation. Glutinous rice vinegar is a very good condiment, containing a small amount of acetic acid, pure aroma, mellow sour taste, and is suitable for dipping or stir-frying. Glutinous rice vinegar contains rich alkaline amino acids, sugar substances, organic acids, vitamin B1, vitamin B2, vitamin C, inorganic salts, minerals, etc., and can also reduce fat, lower blood pressure, lower cholesterol, detoxify, relieve alcohol, digest food, lose weight, calm the nerves, prevent cardiovascular and cerebrovascular diseases.

[0003] The production of vinegar includes three processes of starch hydrolysis into sugar, sugar fermentation into alcohol, and alcohol oxidation into acetic acid. Total acid is an important quality index of vinegar. For brewing vinegar, the higher the acidity, the higher the fermentation degree, and the more sour the vinegar. The total acid in vinegar includes volatile acid and non-volatile acid. Volatile acid includes formic acid, acetic acid, propionic acid, butyric acid, etc., mainly acetic acid; non-volatile acid includes lactic acid, succinic acid, gluconic acid, etc., mainly lactic acid. Studies have shown that the percentage content of volatile acid and non-volatile acid in vinegar is closely related to the flavor of vinegar. If the volatile acid content of vinegar is high and the non-volatile acid content is low, the sour taste is irritating and the aftertaste is short; on the contrary, the sour smell is soft and the aftertaste is long. The glutinous rice vinegar brewed by the traditional industrialized fermentation process has the defects of low non-volatile acid content, irritating sour taste and short aftertaste, so the brewing process needs to be adjusted and optimized to produce high-quality glutinous rice vinegar. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for increasing the non-volatile acid content of glutinous rice vinegar by adjusting the brewing process. The glutinous rice vinegar brewed has rich aroma, soft sour smell, long aftertaste, good taste, and rich nutritional ingredients, and high health value.

[0005] The technical problem to be solved by the present application is solved by the following technical solution:

[0006] A method for increasing the non-volatile acid content of glutinous rice vinegar, comprising the following steps:

[0007] (1) Soak the glutinous rice in water, then cook, cool, add Daqu, stir evenly, then perform alcohol fermentation, filter, and obtain a wine mash with an alcohol content of not less than 10%vol;

[0008] (2) Add bran and traditional Chinese medicine extract to the wine mash, and inoculate acetic acid bacteria, stir evenly, then perform acetic acid fermentation, filter, and obtain a vinegar dregs with an alcohol content of less than 0.5%vol;

[0009] (3) adding salt into the vinegar dregs, sealing, post-ripening, spraying vinegar, aging, filtering, sterilizing, filling, and obtaining the glutinous rice vinegar.

[0010] Further, the adding amount of the Daqu is 1-2% of the mass of the glutinous rice. The microorganisms in the Daqu include molds, yeasts, lactic acid bacteria, etc. The molds play a role in saccharification, hydrolyzing starch in the glutinous rice into sugar. The yeasts play a role in decomposing sugar into alcohol and carbon dioxide.

[0011] Further, the temperature of the alcohol fermentation is 25-30℃. The time of the alcohol fermentation is determined according to the temperature and alcohol content, and the starch contained in the glutinous rice is converted into alcohol as much as possible.

[0012] Further, the adding amount of the bran is 100-150% of the mass of the glutinous rice. The bran can provide sufficient carbon source, nitrogen source, phosphorus source and other nutrients for microorganisms, increase the content of sugar and amino acid in the vinegar, and also play a role in loosening the vinegar dregs, absorbing moisture and storing air, which is beneficial to the aerobic fermentation of acetic acid bacteria.

[0013] Further, the traditional Chinese medicine extract is fresh rehmannia alcohol extract, and the adding amount of the fresh rehmannia alcohol extract is 0.2-0.5% of the mass of the glutinous rice. The fresh rehmannia alcohol extract plays a role in promoting acetic acid fermentation, increasing the content of non-volatile acid in total acid, and obtaining glutinous rice vinegar with soft acid gas and long aftertaste.

[0014] Preferably, the preparation method of the fresh rehmannia alcohol extract is that the fresh rehmannia is sliced, mixed and beaten with ethanol with a volume concentration of 75-85%, the obtained slurry is extracted by heating to 50-60℃, centrifuged, the supernatant is taken, the supernatant is evaporated and concentrated until the solvent is dried, and then freeze-dried to obtain the fresh rehmannia alcohol extract.

[0015] Further, the inoculation amount of the acetic acid bacteria is 5-10% of the mass of the wine mash. The acetic acid bacteria play a role in oxidizing alcohol into acetic acid in the fermentation process.

[0016] Further, the temperature of the acetic acid fermentation is 30-35℃. The time of the acetic acid fermentation is determined according to the temperature and acidity, and the taste is also considered.

[0017] Further, the adding amount of the salt is 1-3% of the mass of the vinegar dregs. Adding salt after the acetic acid fermentation ends can inhibit the oxidation of acetic acid bacteria, prevent the further decomposition of acetic acid, and improve the taste of the glutinous rice vinegar.

[0018] The post-ripening, spraying vinegar, aging, filtering and sterilizing operations in the above technical solution all adopt common methods in the field, which not only can improve the taste and flavor of the glutinous rice vinegar, but also can ensure the edible safety of the glutinous rice vinegar.

[0019] The invention has the beneficial effects of preparing glutinous rice vinegar by using glutinous rice as a raw material through alcohol fermentation and acetic acid fermentation processes. The glutinous rice vinegar not only contains rich nutrients, but also has a mild sour smell, a long aftertaste, and high quality. The total acid content (calculated as acetic acid) is greater than 5.3 g / 100 mL, and the non-volatile acid content (calculated as lactic acid) is greater than 1.5 g / 100 mL, meeting the requirements of GB 18187-2000 "Brewed Vinegar". The unique taste and flavor of the glutinous rice vinegar are conducive to improving the market competitiveness of the product. Specific implementation method:

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific embodiments.

[0021] The following examples and comparative examples are provided with the following raw materials:

[0022] Daqu comes from Shandong Xufang Biotechnology Co., Ltd.

[0023] Acetic acid bacteria were sourced from Shanghai Baiyi Biotechnology Co., Ltd.

[0024] Preparation method of fresh Rehmannia glutinosa ethanol extract: slice 1 kg of fresh Rehmannia glutinosa, add the same weight of 80% ethanol by volume concentration, mix and pulp, heat the resulting pulp to reflux state and extract for 12 hours, centrifuge, take the supernatant, evaporate and concentrate the supernatant until the solvent is evaporated, and freeze-dry to obtain the fresh Rehmannia glutinosa ethanol extract.

[0025] Preparation method of fresh Rehmannia root aqueous extract: slice 1 kg of fresh Rehmannia root, add the same weight of water, mix and slurry, heat the obtained slurry to reflux state and extract for 12 hours, centrifuge, take the supernatant, evaporate and concentrate the supernatant until the water is evaporated, and freeze-dry to obtain fresh Rehmannia root aqueous extract.

[0026] The following examples and comparative examples, which are not described in detail, all use the same process conditions and parameters for the after-ripening, vinegar pouring, aging, filtration, sterilization and filling processes.

[0027] Example 1

[0028] (1) Soak glutinous rice in water for 12 hours and then steam it, cool it to below 30°C, then add 1% Daqu (amount by weight of the glutinous rice) and stir it evenly before fermenting it with alcohol at a temperature of 25-30°C for 10 days. Filter it to obtain a wine mash with an alcohol content of not less than 10% vol.

[0029] (2) adding 120% of the weight of glutinous rice bran and 0.2% of fresh Rehmannia glutinosa alcohol extract to the wine mash, and inoculating 5% of the weight of acetic acid bacteria to the wine mash, stirring evenly and performing acetic acid fermentation at a fermentation temperature of 30-35°C for 9 days, filtering, and obtaining a vinegar mash with an alcohol content of less than 0.5%vol.

[0030] (3) Adding 2% salt of the mass of the vinegar dregs to the vinegar dregs, sealing, post-ripening, drenching, aging, filtering, sterilizing, and filling to obtain the glutinous rice vinegar.

[0031] Example 2

[0032] (1) Steaming the glutinous rice after soaking in water for 12 hours, cooling to below 30℃, then adding 1% Daqu of the mass of the glutinous rice, stirring uniformly, and then performing alcohol fermentation at a fermentation temperature of 25-30℃ for 10 days to obtain a wine mash with an alcohol content of not less than 10%vol.

[0033] (2) Adding 150% bran of the mass of the glutinous rice and 0.3% fresh rehmannia alcohol extract to the wine mash, and then inoculating 5% acetic acid bacteria of the mass of the wine mash, stirring uniformly, and then performing acetic acid fermentation at a fermentation temperature of 30-35℃ for 8 days to obtain vinegar dregs with an alcohol content of less than 0.5%vol.

[0034] (3) Adding 1% salt of the mass of the vinegar dregs to the vinegar dregs, sealing, post-ripening, drenching, aging, filtering, sterilizing, and filling to obtain the glutinous rice vinegar.

[0035] Example 3

[0036] (1) Steaming the glutinous rice after soaking in water for 12 hours, cooling to below 30℃, then adding 1.5% Daqu of the mass of the glutinous rice, stirring uniformly, and then performing alcohol fermentation at a fermentation temperature of 25-30℃ for 9 days to obtain a wine mash with an alcohol content of not less than 10%vol.

[0037] (2) Adding 100% bran of the mass of the glutinous rice and 0.3% fresh rehmannia alcohol extract to the wine mash, and then inoculating 8% acetic acid bacteria of the mass of the wine mash, stirring uniformly, and then performing acetic acid fermentation at a fermentation temperature of 30-35℃ for 10 days to obtain vinegar dregs with an alcohol content of less than 0.5%vol.

[0038] (3) Adding 3% salt of the mass of the vinegar dregs to the vinegar dregs, sealing, post-ripening, drenching, aging, filtering, sterilizing, and filling to obtain the glutinous rice vinegar.

[0039] Example 4

[0040] (1) Steaming the glutinous rice after soaking in water for 12 hours, cooling to below 30℃, then adding 2% Daqu of the mass of the glutinous rice, stirring uniformly, and then performing alcohol fermentation at a fermentation temperature of 25-30℃ for 8 days to obtain a wine mash with an alcohol content of not less than 10%vol.

[0041] (2) adding 120% of the weight of glutinous rice bran and 0.4% of fresh Rehmannia glutinosa alcohol extract to the wine mash, and inoculating 8% of the weight of acetic acid bacteria to the wine mash, stirring evenly and performing acetic acid fermentation at a fermentation temperature of 30-35°C for 8 days, filtering, and obtaining a vinegar mash with an alcohol content of less than 0.5%vol.

[0042] (3) adding 2% of the mass of salt to the vinegar mash, sealing, post-ripening, pouring vinegar, aging, filtering, sterilizing, and filling to obtain glutinous rice vinegar.

[0043] Example 5

[0044] (1) Glutinous rice is soaked in water for 12 hours and then steamed and cooled to below 30° C., and then 2% of the mass of the glutinous rice is added to the glutinous rice. After stirring evenly, the mixture is fermented at a temperature of 25 to 30° C. for 10 days, and filtered to obtain a wine mash with an alcohol content of not less than 10% vol.

[0045] (2) adding 150% of the weight of glutinous rice bran and 0.5% of fresh Rehmannia glutinosa alcohol extract to the wine mash, and inoculating 10% of the weight of acetic acid bacteria to the wine mash, stirring evenly and performing acetic acid fermentation at a fermentation temperature of 30-35°C for 10 days, filtering, and obtaining a vinegar mash with an alcohol content of less than 0.5%vol.

[0046] (3) adding 2% of the mass of salt to the vinegar mash, sealing, post-ripening, pouring vinegar, aging, filtering, sterilizing, and filling to obtain glutinous rice vinegar.

[0047] Comparative Example 1 (adding fresh Rehmannia root water extract)

[0048] (1) Glutinous rice is soaked in water for 12 hours and then steamed and cooled to below 30° C., and then 2% of the mass of the glutinous rice is added to the glutinous rice. After stirring evenly, the mixture is fermented at a temperature of 25 to 30° C. for 10 days, and filtered to obtain a wine mash with an alcohol content of not less than 10% vol.

[0049] (2) adding 150% of the weight of glutinous rice bran and 0.5% of fresh Rehmannia root aqueous extract to the wine mash, and inoculating 10% of the weight of acetic acid bacteria to the wine mash, stirring evenly and performing acetic acid fermentation at a temperature of 30-35° C. for 10 days, filtering, and obtaining a vinegar mash with an alcohol content of less than 0.5% vol.

[0050] (3) adding 2% of the mass of salt to the vinegar mash, sealing, post-ripening, pouring vinegar, aging, filtering, sterilizing, and filling to obtain glutinous rice vinegar.

[0051] Comparative Example 2 (without adding fresh Rehmannia glutinosa ethanol extract)

[0052] (1) soak the waxy rice in water for 12 hours, then steam and cook, cool to below 30℃, then add 2% of the mass of the waxy rice of Daqu, stir to mix, then perform alcohol fermentation, the fermentation temperature is 25-30℃, the fermentation time is 10 days, filter, to obtain a wine mash with an alcohol content of no less than 10%vol.

[0053] (2) add 150% of the mass of the waxy rice of bran to the wine mash, and inoculate 10% of the mass of the wine mash of acetic acid bacteria, stir to mix, then perform acetic acid fermentation, the fermentation temperature is 30-35℃, the fermentation time is 10 days, filter, to obtain a vinegar dregs with an alcohol content of less than 0.5%vol.

[0054] (3) add 2% of the mass of the vinegar dregs of salt to the vinegar dregs, seal, then perform post-ripening, drenching, aging, filtering, sterilizing, and filling, to obtain the waxy rice vinegar.

[0055] The total acid content and non-volatile acid content of the waxy rice vinegar prepared in the above examples and comparative examples are determined respectively, the total acid content is determined according to the standard GB / T 5009.41-2003, and the non-volatile acid content is determined according to the standard GB / T 18187-2000, and the determination results are shown in Table 1.

[0056] Table 1 Total acid content and non-volatile acid content of waxy rice vinegar

[0057]

[0058] As can be seen from the data in Table 1, the total acid content and non-volatile acid content of the waxy rice vinegar prepared in Examples 1-5 of the present application all meet the requirements of GB 18187-2000 “Brewed Vinegar”, and the appropriate addition of the fresh rehmannia alcohol extract during acetic acid fermentation can further improve the total acid content and non-volatile acid content of the prepared waxy rice vinegar, and the acute toxicity test result of the fresh rehmannia alcohol extract is LD 50 >2000mg / kg, and does not affect the edible safety of the waxy rice vinegar.

[0059] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for increasing the non-volatile acid content of glutinous rice vinegar, characterized in that: The following steps are involved: (1) soaking glutinous rice in water and then steaming it, cooling it, then adding Daqu, stirring it evenly, and then fermenting it with alcohol, filtering it, and obtaining a mash with an alcohol content of not less than 10%vol; (2) adding bran and Chinese herbal extract to the mash, inoculating acetic acid bacteria, stirring evenly, performing acetic acid fermentation, and filtering to obtain a mash with an alcohol content of less than 0.5% vol. (3) adding salt to the vinegar mash, sealing, post-ripening, pouring vinegar, aging, filtering, sterilizing, and filling to obtain glutinous rice vinegar; The Chinese medicinal extract is fresh Rehmannia glutinosa ethanol extract, and the amount of fresh Rehmannia glutinosa ethanol extract added is 0.2-0.5% of the mass of glutinous rice; The preparation method of the fresh Rehmannia glutinosa alcohol extract comprises the following steps: slicing the fresh Rehmannia glutinosa, adding ethanol with a volume concentration of 75-85%, mixing and beating the mixture, heating the obtained slurry to 50-60° C. for extraction, centrifuging, taking the supernatant, evaporating and concentrating the supernatant until the solvent is evaporated, and freeze-drying to obtain the fresh Rehmannia glutinosa alcohol extract.

2. The method according to claim 1, wherein: The added amount of the Daqu is 1-2% of the mass of the glutinous rice.

3. The method according to claim 1, wherein: The temperature of the alcohol fermentation is 25-30°C.

4. The method according to claim 1, wherein: The added amount of the bran is 100-150% of the mass of the glutinous rice.

5. The method according to claim 1, wherein: The inoculation amount of the acetic acid bacteria is 5-10% of the quality of the mash.

6. The method according to claim 1, wherein: The temperature of the acetic acid fermentation is 30-35°C.

7. The method according to claim 1, wherein: The amount of salt added is 1-3% of the mass of the vinegar mash.

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