CN112300891A

CN112300891A - Method for preparing raw rice wine by using high-voltage pulse electric field sterilization

Info

Publication number: CN112300891A
Application number: CN201910669588.2A
Authority: CN
Inventors: 徐春
Original assignee: Ningbo Chenshi Biotechnology Co ltd
Current assignee: Ningbo Chenshi Biotechnology Co ltd
Priority date: 2019-07-24
Filing date: 2019-07-24
Publication date: 2021-02-02

Abstract

The invention discloses a method for preparing raw rice wine by utilizing high-voltage pulse electric field sterilization, which comprises the following steps: 1) processing glutinous rice to obtain cooked glutinous rice; 2) uniformly mixing the cooked glutinous rice and distiller's yeast accounting for 0.1-0.3% of the weight of the glutinous rice, fermenting for 2-3 days at 28-30 ℃, adding water accounting for 1-4 times of the weight of the glutinous rice, uniformly stirring, continuing fermenting for 2-7 days, stopping fermentation, and separating to obtain fermented wine liquid; 3) and (3) placing the fermented wine liquid in a high-voltage pulse electric field for sterilization treatment to obtain the raw fresh rice wine, wherein the strength of the pulse electric field is 30-40 kV/cm, the number of pulses is 50-100, the pulse width is 10-40 mu s, the pulse frequency is 500-1000 Hz, and the treatment time is 100-150 mu s. The invention adopts high-voltage pulse electric field sterilization to avoid the inactivation of sucrose invertase by heating, the prepared rice wine has fresh taste, delicious taste and rich nutrition, solves the long-term contradiction that the rice wine has no fresh taste and can not be preserved for a long time after the taste is fresh, and provides a novel rice wine category which accords with the health concept of modern consumers.

Description

Method for preparing raw rice wine by using high-voltage pulse electric field sterilization

Technical Field

The invention belongs to the technical field of wine preparation, particularly relates to a fresh rice wine and a preparation method thereof, and more particularly relates to a method for preparing the fresh rice wine by utilizing high-voltage pulse electric field sterilization.

Background

Rice wine, also known as sweet wine, fermented glutinous rice or fermented glutinous rice, is a traditional characteristic low-alcohol brewed wine in China, belongs to yellow wine, is mainly prepared by taking rice, long-shaped rice, red rice, black rice or glutinous rice and other grain rice as raw materials and fermenting the raw materials by microorganisms, is rich in glucose, maltose, amino acid, vitamin, organic acid, polysaccharide and other components, has the effects of stimulating appetite and removing greasiness, promoting the production of body fluid to quench thirst, activating qi and nourishing blood, relaxing muscles and tendons and activating blood circulation, nourishing yin and tonifying kidney and the like, and has huge market potential and development prospect.

The prior rice wine in the market mainly comprises rice wine in Zhejiang area, Xiaogan rice wine in Hubei area and the like, and the brewing process mainly comprises the following steps: selecting rice → washing rice → soaking rice → steaming → cooling → mixing with yeast → placing in a vat nest → preserving heat and saccharifying → fermenting → squeezing → filtering → sterilizing → filling → finished product, wherein the sterilizing process mostly adopts a heat sterilization mode. The heat sterilization technology is an important control technology in the technical field of food processing, and mainly kills microorganisms in food and inactivates enzymes in the food through high temperature and high heat, so as to achieve the purposes of improving the quality of the food, prolonging the storage period of the food and ensuring the safety of the food, wherein the heat sterilization mode mainly comprises pasteurization and high-temperature instantaneous sterilization. However, both of these processes have inherent defects, such as insensitivity to heat-resistant microorganisms, high energy consumption and fixed investment, difficulty in precise control, frequent overheating, and the like, and more importantly, the high temperature effect in the heat sterilization process tends to result in the deterioration of the quality of food, mainly including color change, taste change, aroma loss, nutrient component damage, texture change, and the like.

Along with the continuous improvement of living standard, the consciousness of people on healthy drinking is gradually enhanced, and a brand-new drinking concept of low-alcohol health, nutrition and health care is formed. The nutrient components and flavor of the rice wine brewed at home are far higher than those of the rice wine brewed at market because the rice wine is not pasteurized, however, the home brewing is greatly influenced by climate and environment, the yield of fermented wine is low, and in addition, the rice wine contains more mixed bacteria because of no sterilization treatment, so that the rice wine is easy to be rancid due to more mixed bacteria after fermentation, and the brewed rice wine has the defects of short preservation time, easy aging, incapability of commercial production and the like.

Disclosure of Invention

The invention discovers that the traditional heat sterilization process can destroy the flavor of the rice wine in the rice wine preparation process, can cause the loss of the natural fragrance of the rice wine, can also cause the loss of the natural delicate flavor of the rice wine, can generate bitter miscellaneous flavor and can cause the loss of nutritional ingredients. The invention aims to provide a fresh rice wine and a preparation method thereof, which adopts a specific sterilization mode to keep sucrose invertase in the rice wine positive and reduce the loss of bad flavor or nutrition, thereby providing a novel rice wine with rich nutrition and delicious taste.

Based on the above description, as a first aspect of the present invention, the present invention provides a method for preparing raw rice wine.

Preferably, the preparation method of the raw fresh rice wine comprises the following steps:

1) processing glutinous rice to obtain cooked glutinous rice;

2) uniformly mixing the cooked glutinous rice and distiller's yeast accounting for 0.1-0.3% of the weight of the glutinous rice, fermenting for 2-3 days at 28-30 ℃, adding water accounting for 1-4 times of the weight of the glutinous rice, uniformly stirring, continuing fermenting for 2-7 days, stopping fermentation, and separating to obtain fermented wine liquid;

3) and placing the fermented wine liquid in a high-voltage pulse electric field for sterilization treatment to obtain the raw fresh rice wine.

Preferably, the parameters in the sterilization process in the step 3) are set as follows: the electric field intensity is 30-40 kV/cm, the number of pulses is 50-100, the pulse width is 10-40 mu s, the pulse frequency is 500-1000 Hz, and the processing time is 100-150 mu s.

Preferably, the preparation method of the cooked glutinous rice in the step 1) comprises the following steps: cleaning the sticky rice, soaking the sticky rice for 10-18h at room temperature, cooking the soaked sticky rice for 20-30min, and then showering and cooling the sticky rice to 30-35 ℃.

Wherein, when the sticky rice is soaked in water, the mass ratio of the rice to the water is 1:2 to 3.5; wherein, the cooked glutinous rice is required to have complete particles, hard outside and soft inside, and loose and unbreakable grains; and (3) spraying the steamed glutinous rice with tap water to separate and cool rice grains, wherein the spraying time is properly prolonged or shortened according to the amount, season and temperature of the glutinous rice.

Preferably, in the step 2), the fermentation is stopped when the alcoholic strength of the fermented wine is 6-14% vol, the total sugar content is 10-160g/L, and the total acid content is 0.5-10 g/L.

Preferably, the method for separating and obtaining the fermented wine liquid in the step 2) comprises the following steps: and carrying out filter pressing or centrifugal separation on the fermentation liquor to obtain fermented liquor, and filtering the fermented liquor.

Wherein, the fermented wine liquid can be separated by a squeezer, a plate-and-frame filter press, a butterfly centrifuge and the like.

Preferably, the filtration is performed by using a microporous membrane with a pore size of 0.30 to 0.50 μm. Wherein, the pore size of the membrane in the membrane filtration can be adjusted by the technicians in the field according to the needs.

In the present invention, the amount of the koji, which is conventionally used by those skilled in the art, may be adjusted as needed by those skilled in the art, and as a preferred embodiment of the present invention, in the step 1), the amount of the koji is 0.1 to 0.3% by weight of the glutinous rice, which is one of the advantages that the glutinous rice can be sufficiently fermented, and the wine can be prevented from having bitterness due to an excessively large amount of the koji.

As a second aspect of the present invention, the present invention provides a method for preparing aerated raw rice wine by aerating gas during the rice wine preparation process to prepare a gas-containing rice wine.

Preferably, the preparation method of the aerated fresh rice wine comprises the following steps:

1) processing glutinous rice to obtain cooked glutinous rice;

3) placing the fermented wine liquid in a high-voltage pulse electric field for sterilization treatment;

4) and (3) filling gas into the sterilized fermented wine liquid to ensure that the concentration of the gas in the fermented wine liquid reaches 2-6g/L, thus obtaining the aerated fresh rice wine.

Preferably, the gas is food grade CO₂、N₂Or CO₂And N₂Gas obtained by mixing according to a certain proportion.

Wherein, CO is contained in the mixed gas₂And N₂The volume ratio of (1-100): the ratio of (1 to 100) may be, for example, 1:1, 1:2, 2:1, 5:95, or the like.

Preferably, the filtration is performed by using a microporous membrane with a pore size of 0.30 to 0.50 μm.

As a third aspect of the invention, the invention aims to provide a fresh rice wine, which is prepared by sterilizing the rice wine by using a non-thermal sterilization technology instead of thermal sterilization, so that sucrose invertase in the rice wine is not inactivated due to high temperature, the fresh flavor of the rice wine is kept, and the microbial residual quantity in the rice wine reaches the national standard requirement by non-thermal sterilization, so that the shelf life is prolonged, and the novel rice wine with rich nutritional value and fresh and delicious taste is provided.

Preferably, the alcohol content of the raw fresh rice wine is 6-14% vol, and the sucrose invertase is positive.

Preferably, the total sugar content of the raw fresh rice wine is 10-160g/L, and the total acid content is 0.5-10 g/L.

Preferably, the raw rice wine includes both non-aerated and aerated types, i.e., both non-aerated and aerated rice wine can be prepared by controlling whether or not gas is aerated during the preparation of rice wine.

1) processing glutinous rice to obtain cooked glutinous rice;

Preferably, the method further comprises the step of aerating the fermented wine liquid after the high-voltage pulse electric field sterilization treatment so that the gas concentration in the fermented wine liquid reaches 2-6 g/L.

As a fourth aspect of the invention, the invention provides the use of high-voltage pulse electric field sterilization for improving the delicate flavor of rice wine.

The invention group surprisingly finds that the rice wine prepared by adopting the high-voltage pulse electric field sterilization method has the fresh taste obviously superior to that prepared by adopting pasteurization, high-temperature instantaneous sterilization and other heat sterilization, and the physical and chemical indexes of the rice wine prepared by different sterilization methods are analyzed and determined, so that the content of the fresh taste substances in the rice wine can be improved by adopting the high-voltage pulse electric field sterilization.

Therefore, the invention discloses the application of high-voltage pulse electric field sterilization in improving the delicate flavor of rice wine.

Preferably, the rice wine umami taste is increased by increasing the content of umami substances in the rice wine.

Preferably, the umami taste substance is aspartic acid.

The invention has the beneficial effects that:

(1) the rice wine preparation method adopts the high-voltage pulse electric field for sterilization treatment, so that the prepared rice wine sucrose invertase is positive, compared with the existing rice wine in the market, the rice wine has the advantages of fresh taste, delicious taste and rich nutrition, and the contradiction that the rice wine is not fresh in taste and cannot be stored for a long time after the taste is fresh is thoroughly solved, so that a novel rice wine class conforming to the health concept of modern consumers is provided, and the rice wine has good market development value.

(2) The invention prepares the aerated fresh rice wine by filling gas into the rice wine, further enriches the types of the rice wine, and the aerated fresh rice wine containing the gas can give people a feeling of refreshing and stopping the mouth when drinking, and can obtain the favor of young consumers.

(3) The content of the umami amino acid aspartic acid in the fresh rice wine prepared by the preparation process is obviously higher than that of the rice wine prepared by adopting heat sterilization and the rice wine not subjected to sterilization, so that the prepared fresh rice wine has fresh and aromatic taste and better mouthfeel compared with the rice wine prepared by the traditional process.

(4) The preparation process of the invention only adds water but not fermentation microorganisms after 2-3 days of fermentation, and promotes saccharification and fermentation by controlling the fermentation process, thereby avoiding the increase of bitter taste caused by the increase of alcoholic strength due to excessive fermentation and the increase of sour taste caused by the reproduction of acetic acid bacteria, and ensuring that the rice wine obtained by fermentation is fresh, sweet, delicious, unique in flavor and rich in nutrition.

Drawings

FIG. 1 is a process flow chart of the raw fresh rice wine of the present invention.

Detailed Description

Fresh rice wine

The fresh wine is wine prepared without pasteurization and other heat sterilization processes, for example, fresh beer, which completely preserves the original components of the wine without heat sterilization, has the advantages of rich nutrition, delicious and thick taste, strong aroma and the like, and becomes a healthy drink favored by consumers. Wherein, the sucrose invertase is positive as the characteristic mark of the fresh wine, and the authenticity of the fresh wine is identified by detecting the activity of the sucrose invertase in the wine. Sucrose invertase is extremely easy to be inactivated by heat, and is inactivated when the temperature is higher than 60 ℃, and the wine liquid generates undesirable color change, so the temperature control in the wine production process is very important for preparing fresh wine.

In the present invention, the raw rice wine refers to rice wine prepared without heat treatment such as pasteurization. After the conventional rice wine in the market is fermented, the conventional rice wine can meet the requirement of stable preservation only by pasteurization or high-temperature instant sterilization, but the taste and the nutrition of the rice wine are greatly damaged. The invention provides a novel rice wine product, which does not undergo heat sterilization processes such as pasteurization and the like in the preparation process, adopts a low-heat or non-heat sterilization process, ensures that the microbial indexes in the wine liquor meet the national standard, greatly keeps the freshness and nutrition of the rice wine, and ensures that the sucrose invertase in the wine liquor is positive, so that the flavor and the nutrition of the prepared rice wine are similar to those of the freshly brewed non-sterilized rice wine.

Flavour material

In the present invention, the flavor substance of sake refers to a substance that causes sake to exhibit its peculiar umami taste and/or aroma. After glutinous rice is cooked and gelatinized, the glutinous rice is converted into fermentable saccharides under the action of enzyme in a saccharifying agent, the fermentable saccharides are converted into alcohol and carbon dioxide under the anaerobic condition through the fermentation action of yeast, organic acid, alcohol, ester, ketone, phenol and free amino acid are generated under the enzymatic reaction and the chemical reaction of microorganisms along with the lapse of fermentation time, and meanwhile, various substances are dissolved out by cells due to the death of the microorganisms to jointly form the flavor substance of the wine body. The flavor substances in the rice wine mainly comprise saccharides, amino acids and polypeptides, organic acids, fatty acids, polyphenols, mineral elements, vitamins, alcohols, esters, aldehydes, acids, ketones and the like, wherein the flavor substances can be divided into two categories of nonvolatile flavor substances and volatile flavor substances.

The wine is rich in nitrogen-containing substances, and the wine is fragrant, delicious and mellow when the nitrogen-containing substances in the wine are high. The amino acids have various tastes such as fresh, sweet, bitter and astringent tastes, and endow rice wine with rich taste hierarchy, so that the rice wine has delicious, mellow, rich, soft and moist and harmonious taste characteristics, wherein the taste development amino acids in the rice wine comprise sweet amino acids (such as threonine Thr, serine Ser, glycine Gly, alanine Ala and proline Pro), bitter amino acids (such as valine Val, cysteine Cys, isoleucine Ile, leucine Leu, methionine Met, lysine Lys, histidine His, arginine Arg and phenylalanine Phe) and fresh amino acids (such as aspartic acid Asp and glutamic acid Glu).

The organic acid in the rice wine mainly comprises lactic acid, acetic acid, tartaric acid, oxalic acid, fumaric acid, succinic acid, malic acid, etc. The organic acid is not only aroma but also flavor-developing substances in the rice wine, and the organic acid and other flavor-developing and flavor-developing substances form the special taste and aromatic smell of the rice wine; in addition, the organic acid can enhance the thickness of the rice wine, reduce the sweetness, and has the functions of buffering and coordinating other fragrant components. The rice wine with less acid content has light taste and inconsistent wine body; if the acid content is too high, the sour taste will affect the whole flavor of the wine, and the content ratio of various acids will also have a great influence on the wine. Among the organic acids, acetic acid is a volatile acid, and for the volatile acid, the smaller the molecular weight, the softer the taste, and the larger the molecular weight, the stronger the irritation; lactic acid, succinic acid, malic acid, tartaric acid, oxalic acid, etc. are non-volatile acids, and they can increase the richness of the wine.

The volatile flavor substances in the rice wine are main substances forming the aroma of the rice wine, and comprise alcohol, ester, acid/aldehyde, alkane/olefin and the like, and the aroma components belong to trace components in the rice wine, but the components have great influence on the flavor of the rice wine, wherein the volatile aroma components have higher contents of higher alcohol and ester, account for more than 60 percent of the aroma components, and have lower contents of aldehyde, ketone, acid and other phenolic substances.

Low heat or non-heat sterilization

The low heat sterilization refers to the food is treated at a relatively low temperature so as to achieve the purpose of killing microorganisms in the food, and in the invention, the low heat sterilization refers to the temperature of the sterilization treatment which is less than 60 ℃.

The non-heat sterilization, namely cold sterilization, is a novel sterilization technology which does not use heat energy to kill microorganisms, can ensure the safety of food in the aspect of microorganisms, can better keep the inherent nutrient components, the texture, the color and the freshness of the food, and meets the requirements of consumers on the nutrition and the original taste and flavor of the food. The low heat and non-heat sterilization methods suitable for the present invention are mainly as follows.

1. Microwave sterilization

The microwave radiation belongs to low-energy electromagnetic radiation and has thermal effect and electromagnetic effect on organisms, wherein the thermal effect refers to that under the action of a strong microwave magnetic field, the space structure of microorganisms is changed or destroyed due to the temperature rise of cells of the microorganisms, so that protein is denatured and bioactivity is lost; the electromagnetic effect means that high-frequency electromagnetic field radiation generated by microwave penetrates the cell wall of the microorganism to destroy the molecular structure of DNA and protein in the cell of the microorganism, so that the microorganism is killed; of the two effects, the electromagnetic effect plays a dominant role and can achieve the killing of microorganisms at lower temperatures. In the invention, the device adopted for microwave sterilization is a YQ36S-05 microwave sterilization machine, the microwave working frequency is 2450MHz, the microwave power is 36 +/-5% kW, and the real-time measurement and control of the temperature of the equipment are carried out through an infrared temperature control system in the whole process; the parameters in the sterilization process are set to be that the microwave energy received by the fermented wine liquid is 84-124 kilojoules/L, the sterilization temperature is 45-58 ℃, in the invention, the microwave sterilization process is divided into two stages, including a temperature rise sterilization stage and a constant temperature sterilization stage, the temperature of the fermented wine liquid detected by a microwave sterilization machine is controlled to rise to the set temperature through a program in the temperature rise sterilization stage, even if the temperature rises to 45-58 ℃, the temperature rise sterilization time is 2-10 min; keeping the temperature of the fermented liquor at 45-58 deg.C in constant temperature sterilization stage, and sterilizing at constant temperature for 10-20 min.

2. High voltage Pulsed Electric Field (PEF)

The high-voltage pulse electric field is characterized in that under the high-voltage pulse electric field, a negative pulse wave crest forms rapidly-changed pressure on a cell membrane, so that the structure of the high-voltage pulse electric field is loose, the permeability of the cell membrane is rapidly damaged under the synergistic effect of the negative pulse wave crest and the positive pulse wave crest, and the high-voltage pulse electric field has an inhibiting effect on microorganisms. In the invention, the used high-voltage pulse electric field device is OSU-4L, and the pulse parameters are as follows: the electric field intensity is 30-40 kV/cm, the number of pulses is 50-100, the pulse width is 10-40 mu s, the pulse frequency is 500-1000 Hz, and the processing time is 100-150 mu s.

3. Plasma sterilization technique

Plasma is an ionized gaseous substance consisting of atoms with some electrons being deprived and positive and negative electrons generated after the atoms are ionized, and is divided into high-temperature plasma and low-temperature plasma, and various assumptions exist about the sterilization mechanism of plasma, and it may be that cell membranes are damaged due to charge discharge, or a large amount of ultraviolet rays generated in the plasma forming process destroy the genetic substances of microorganisms, resulting in the death of the microorganisms. The plasma sterilization has the advantages of low sterilization temperature, high sterilization speed and simple and convenient operation. The low-temperature plasma device used in the invention is dielectric barrier discharge low-temperature plasma (Nanjing Suman plasma technology Co., Ltd.), the processing frequency is 5-10 kHz, the processing air gap distance is 5-15 nm, the processing power is 30-50W, the processing time is 5-15 min, and the processing temperature is room temperature.

4. Radiation sterilization (radiation sterilization)

The radiation sterilization technique uses electron rays, X rays, gamma rays and radioactive isotopes in electromagnetic waves⁶⁰Co and³⁷the method for killing the microorganisms by the Cs rays basically has the functions of destroying DNA or cell membranes of the microorganisms, achieving the sterilization effect by interfering the metabolism of the microorganisms, and has the advantages of high sterilization efficiency, wide application range, time saving and cost saving. In the present invention, use is made of⁶⁰And (3) performing sterilization treatment by using a Co radiation sterilizer (Yunnan Huayuan nuclear radiation technology limited company), wherein the radiation dose is 5-20 kGy, and the irradiation time is 15-30 min.

5. Ultrasonic sterilization

Ultrasonic sterilization refers to the treatment of food with sound waves with frequency greater than 20kHz, which leads to bacterial death, virus inactivation and enzyme activity inhibition through the mechanical effect and chemical effect of ultrasonic waves. In the invention, the ultrasonic sterilization device is an SB-5200-DTD ultrasonic sterilizer, Ningbo Xinzhi Biotechnology GmbH, the ultrasonic power is 40-200W, the treatment temperature is 20-40 deg.C, and the treatment time is 5-20 min.

6. Ultraviolet sterilization

The DNA of the microorganism is crosslinked by ultraviolet irradiation, so that the DNA unwinding and replication are prevented, and the propagation of the microorganism is inhibited. The ultraviolet sterilization device used in the invention is an MRC-250B intelligent artificial ultraviolet climatic chamber (Philips low-pressure ultraviolet lamp, Shanghai Baidian instruments and equipments Co., Ltd.), the radiation power is 10-40W, the radiation distance is 5-10cm, and the radiation time is 10-30 min.

7. Ultra-high pressure (UHP) sterilization

The ultra-high pressure technology is to treat food under the pressure of 100-1000MPa by using water or other fluid medium as a pressure transmission medium under the condition of room temperature or mild heating, so as to inactivate high molecular substances such as enzyme, protein, starch and the like in the food and kill microorganisms such as bacteria and the like in the food. The model of the ultra-high pressure sterilization equipment used in the invention is HPP600MPA/3L, and the parameters of Baotou Kogyo high-voltage technology Limited liability company are as follows: the treatment temperature is 20-35 ℃, the treatment pressure is 300-450MPa, and the pressure maintaining time is 5-25 min.

8. Pulsed magnetic field sterilization

The pulsed magnetic field sterilization is to sterilize by strong magnetism at normal temperature, the device mainly comprises an infusion tube and a spiral coil arranged outside the infusion tube, and when a material passes through the infusion tube, microorganisms in the material are killed by the generated magnetic induction intensity of 2-10T. The pulse magnetic field sterilization device used in the invention is an HSM-S20 type pulse strong magnetic field device, the voltage range is 0-2.0kV, the magnetic flux range is 0-4.22T, the time interval between two pulses is 15S, and the parameters are as follows: the number of the pulses is 5-25, the magnetic field intensity is 2-10T, and the pulse width is 5-25 ms.

When the raw and fresh rice wine is prepared by adopting the different sterilization modes, the different sterilization modes are unexpectedly found to have different influences on different flavor substances in the rice wine, so that certain influences are generated on the flavor and the taste of the rice wine.

Detailed Description

The present invention will be described in more detail with reference to examples. It is to be understood that the practice of the invention is not limited to the following examples, and that any variations and/or modifications may be made thereto without departing from the scope of the invention.

In the invention, all parts and percentages are weight units, and all equipment, raw materials and the like can be purchased from the market or are commonly used in the industry, if not specified. Unless otherwise indicated, the examples employ methods that are within the ordinary skill in the art. SA 402B electronic tongue (equipped with 2 reference electrodes and 5 taste sensors, japan instrument company), and internal solution, reference solution, anionic solution, cationic solution and pretreatment solution were purchased from japan instrument company.

Example 1

A preparation method of raw rice wine mainly comprises the following steps:

(1) rice soaking: selecting fresh glutinous rice without mildewing, removing dust, bran shells and impurities attached to the surfaces of rice grains, adding water into the glutinous rice to ensure that the mass ratio of the glutinous rice to the water is 1:2, and soaking for 10 hours at room temperature;

(2) and (3) cooking: cooking the soaked glutinous rice for 20 min;

(3) flushing: spraying the steamed glutinous rice with tap water to separate and cool the rice grains, and keeping the temperature of the glutinous rice at 30 ℃;

(4) fermentation: sequentially adding glutinous rice and distiller's yeast into a fermentation tank, stirring uniformly, wherein the addition amount of the distiller's yeast is 0.1% of the weight of the glutinous rice, stacking and fermenting at 28 deg.C for 2 days, adding water 1 times the weight of the glutinous rice, stirring uniformly, continuing to ferment at 28 deg.C for 2 days, and terminating fermentation;

(5) squeezing: squeezing fermented wine mash by a squeezer, separating wine liquid and wine lees, and filtering the wine liquid obtained after squeezing by a microporous membrane with the aperture of 0.30 mu m;

(6) and (3) sterilization: placing the filtered fermented wine liquid in a high-voltage pulse electric field, setting the electric field intensity to be 30kV/cm, the number of pulses to be 50, the pulse width to be 10 mus, the pulse frequency to be 500Hz, and the processing time to be 100 mus;

(7) filling: and (5) carrying out low-temperature pressure-maintaining filling on the sterilized wine liquid by adopting a negative pressure type filling machine to obtain a finished product.

Example 2

A preparation method of raw rice wine mainly comprises the following steps:

(1) rice soaking: selecting fresh glutinous rice without mildewing, removing dust, bran shells and impurities attached to the surfaces of rice grains, adding water into the glutinous rice to enable the mass ratio of the glutinous rice to the water to be 1:3, and soaking for 15 hours at room temperature;

(2) and (3) cooking: cooking the soaked glutinous rice for 25 min;

(3) flushing: spraying the steamed glutinous rice with tap water to separate rice grains and cooling, and keeping the temperature of the glutinous rice after being sprayed with rice at 32 ℃;

(4) fermentation: sequentially adding glutinous rice and distiller's yeast into a fermentation tank, stirring uniformly, wherein the addition amount of the distiller's yeast is 0.2% of the weight of the glutinous rice, performing stacking fermentation at 30 ℃ for 3 days, adding water 2 times the weight of the glutinous rice as a raw material, stirring uniformly, continuing to perform heat preservation fermentation at 30 ℃ for 5 days, and stopping fermentation;

(5) squeezing: squeezing fermented wine mash by a squeezer, separating wine liquid and wine lees, and filtering the wine liquid obtained after squeezing by a microporous membrane with the aperture of 0.35 mu m;

(6) and (3) sterilization: placing the filtered fermented wine liquid in a high-voltage pulse electric field, setting the electric field intensity to be 40kV/cm, the number of pulses to be 100, the pulse width to be 40 mus, the pulse frequency to be 1000Hz, and the processing time to be 120 mus;

Example 3

A preparation method of aerated fresh rice wine mainly comprises the following steps:

(1) rice soaking: selecting fresh glutinous rice without mildewing, removing dust, bran shells and impurities attached to the surfaces of rice grains, adding water into the glutinous rice to ensure that the mass ratio of the glutinous rice to the water is 1:2, and soaking for 12 hours at room temperature;

(2) and (3) cooking: cooking the soaked glutinous rice for 20 min;

(4) fermentation: sequentially adding glutinous rice and distiller's yeast into a fermentation tank, stirring uniformly, wherein the addition amount of the distiller's yeast is 0.1% of the weight of the glutinous rice, performing stacking fermentation at 28 deg.C for 2 days, adding water 4 times the weight of the glutinous rice, stirring uniformly, continuing fermentation at 28 deg.C for 5 days, and terminating fermentation;

(5) squeezing: squeezing fermented wine mash by a squeezer, separating wine liquid and wine lees, and filtering the wine liquid obtained after squeezing by a microporous membrane with the aperture of 0.40 mu m;

(6) and (3) sterilization: placing the filtered fermented wine liquid in a high-voltage pulse electric field, setting the electric field intensity to be 30kV/cm, the number of pulses to be 50, the pulse width to be 10 mus, the pulse frequency to be 500Hz, and the processing time to be 140 mus;

(7) filling and inflating: filling the sterilized wine liquid with a negative pressure type filling machine at low temperature under pressure, and filling purified food-grade CO₂Gas, so that the gas concentration in the fermented wine liquid reaches 2g/L, wherein CO is generated during aeration₂Controlling the pressure to be 0.05-0.08 MPa, and obtaining the finished product.

Example 4

(1) rice soaking: selecting fresh glutinous rice without mildew phenomenon, removing dust, bran shells and impurities attached to the surfaces of rice grains, adding water into the glutinous rice to ensure that the mass ratio of the glutinous rice to the water is 1:3.5, and soaking for 18 hours at room temperature;

(2) and (3) cooking: cooking the soaked glutinous rice for 30 min;

(3) flushing: spraying the steamed glutinous rice with tap water to separate rice grains and cooling, and keeping the temperature of the glutinous rice after being sprayed with rice at 35 ℃;

(4) fermentation: sequentially adding glutinous rice and distiller's yeast into a fermentation tank, stirring uniformly, wherein the addition amount of the distiller's yeast is 0.3% of the weight of the glutinous rice, performing stacking fermentation at 30 ℃ for 3 days, adding water 3 times the weight of the glutinous rice as a raw material, stirring uniformly, continuing to perform heat preservation fermentation at 30 ℃ for 7 days, and stopping fermentation;

(5) squeezing: squeezing fermented wine mash by a squeezer, separating wine liquid and wine lees, and filtering the wine liquid obtained after squeezing by a microporous membrane with the aperture of 0.50 mu m;

(6) and (3) sterilization: placing the filtered fermented wine liquid in a high-voltage pulse electric field, setting the electric field intensity to be 35kV/cm, the number of pulses to be 80, the pulse width to be 25 mu s, the pulse frequency to be 800Hz, and the processing time to be 150 mu s;

(7) filling and inflating: filling the sterilized wine liquid with a negative pressure type filling machine at low temperature under pressure, and filling purified food-grade N₂To make the gas in the fermented wine liquidThe volume concentration reaches 6g/L, wherein N is generated during inflation₂Controlling the pressure to be 0.05-0.08 MPa, and obtaining the finished product.

Comparative example 1

In this comparative example, the obtained liquor was sterilized by pasteurization at 65 ℃ for 30min, and the other procedures were as described in example 1.

Comparative example 2

In this comparative example, the obtained wine was sterilized by high temperature instantaneous sterilization at 130 ℃ for 5 seconds, and the other procedures were as described in example 1.

Comparative example 3

In this comparative example, the fermented liquor was not sterilized, and the other procedures were the same as those described in example 1.

The physical and chemical indexes, hygienic indexes and sensory quality of the samples obtained in the examples and the comparative examples are detected.

The amino acid state ammonia content and the free amino acid content of the samples obtained in the examples and the comparative examples are carried out Measurement of

Amino acid nitrogen: amino acid nitrogen was determined with reference to GB/T5009.235-2016.

Determination of free amino acids: the content of free amino acid is determined by reference to GB/T5009.124-2016.

The results of the experiment are shown in tables 1 and 2.

TABLE 1 determination of amino acid nitrogen content in different samples

	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2	Comparative example 3
								Amino acid nitrogen g/L	1.357	1.406	1.375	1.413	1.029	1.107	1.401

The experimental results show that the content of amino acid nitrogen in the glutinous rice wine obtained by adopting high-voltage pulse electric field sterilization is obviously higher than that of heat sterilization, on one hand, substances such as amino acid, polyphenol and the like in the wine are oxidized and browned due to high temperature to reduce free amino acid, and on the other hand, the heating can damage the structure of the amino acid to cause partial amino acid loss, so that the nutritive value is reduced.

TABLE 2 determination of the free amino acid content in the different samples

The content of bitter amino acid and astringent amino group in the rice wine is relatively high by measuring the content of free amino acid, which may have a certain relation with the taste of the rice wine, such as bitter taste and astringent taste. The invention unexpectedly discovers that the content of the aspartic acid in the rice wine prepared by the method is obviously higher than that in comparative examples 1 and 2 and also higher than that in comparative example 3. And the aspartic acid is used as the umami amino acid, the content of the aspartic acid is increased, so that the prepared rice wine is likely to have stronger umami taste and more delicious taste.

The content of amino acid is different depending on various elements, and different sterilization modes can be due to different action mechanisms, so that the synthesis of certain amino acid is promoted, or certain amino acid is decomposed, and the specific mechanism is needed to be further researched.

(II) measurement of organic acid content of samples obtained in examples and comparative examples

Total acid was determined with reference to GB/T13662-2018.

The contents of acetic acid, malic acid, lactic acid, succinic acid and citric acid in the glutinous rice wine are determined by referring to the GB/T5009.157-2016 method.

TABLE 3 determination of the organic acid content in the different samples

Components	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2	Comparative example 3
								Total acid (g/L)	2.58	4.14	6.77	7.13	2.65	2.50	2.36
Acetic acid (mg/L)	2.95	3.02	3.04	3.20	3.25	3.57	3.11
								Malic acid (mg/L)	2.51	2.55	2.60	2.49	2.25	2.39	2.50
Lactic acid (mg/L)	7.39	7.87	7.87	7.52	6.54	6.68	6.72
								Succinic acid (mg/L)	14.25	13.95	15.07	14.86	15.23	15.74	16.14
Citric acid (mg/L)	3.85	3.61	3.76	3.99	3.75	3.82	3.78

As can be seen from the experimental results, the organic acid content in the rice wine is relatively high in succinic acid and lactic acid, and the organic acid content in the examples and the comparative examples is relatively similar. In the organic acid of the rice wine, the lactic acid is softer, so that the good flavor can be brought to the rice wine, and the mellow feeling of the rice wine is enhanced. However, the acetic acid taste in the rice wine is not favored by people, and most of the acetic acid taste is too high due to the introduction of excessive mixed bacteria in the brewing process, so that a feeling of rancidity can be brought to drinkers.

(III) measurement of alcohol content, sugar content and sucrose invertase Activity of samples obtained in examples and comparative examples

And (3) detecting the alcoholic strength: the measurement was carried out by distillation specific gravity method.

Total sugars (in glucose): total sugars were determined with reference to GB/T13662-2018.

The sucrose invertase activity was measured using sucrose invertase test paper.

TABLE 4 determination of alcohol content, Total sugar and sucrose invertase Activity in different samples

	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2	Comparative example 3
								Alcohol content: % (v/v)	13.0	9.1	6.7	7.5	12.0	12.6	13.2
Total sugar g/L	104.1	120.7	137.5	148.2	103.5	104.3	109.5
								Sucrose invertase Activity	Positive for	Positive for	Positive for	Positive for	Negative of	Negative of	Positive for

According to the experimental result, the alcohol content of the rice wine prepared by the method is 6-14%, the total sugar is more than 100g/L, and the sucrose invertase is positive and meets the judgment standard of the fresh wine.

(IV) measurement of taste indexes of samples obtained in examples and comparative examples

The acid, sweet, bitter, astringent, salty and umami taste of rice wine was determined using an SA 402 electronic tongue equipped with 6 test sensors and 2 reference sensors, wherein CAO was used to test sour taste, GL1 was used to test sweet taste, COO was used to test bitter taste, AE1 was used to test astringent taste, CTO was used to test salty taste and AEE was used to test umami taste.

After the sensor is activated and self-balanced, soaking the sensor in a reference solution for 30s to measure a reference potential Vr, then soaking the sensor in a sample solution to be measured for 30s to measure a sample solution potential Vs, wherein the Vs-Vr is the relative strength value of the sample in sour, sweet, bitter, astringent, salty and delicate flavor; each sample was assayed in triplicate and the average was taken. The results of the experiments are shown in the following table:

TABLE 5 relative intensity values of taste indices

The electronic tongue measurement result shows that the rice wine is mainly astringent and bitter. The samples of comparative example 1 and comparative example 2 had a large relative intensity value of bitterness and astringency and a small relative intensity value of umami, indicating that the taste of the samples was dominated by astringency and bitterness and the umami was weak. Although the samples of examples 1-4 are mainly astringent and bitter, the relative strength values of astringent and bitter are obviously reduced compared with comparative examples 1 and 2, and the relative strength value of umami is obviously increased compared with comparative examples 1 and 2, which shows that the rice wine prepared by the invention has weaker astringent taste, stronger umami and more harmonious taste. Moreover, by measuring the relative strength values of the taste indexes of the rice wine in the comparison example 3, the taste indexes of the rice wine are close to those of the comparison example 3, which shows that the high-voltage pulse electric field sterilization mode of the invention leads the prepared rice wine to have better delicate flavor compared with the heat sterilization mode, the delicate flavor is equivalent to that of the fresh rice wine which is not sterilized, and the increased delicate flavor is probably caused by the increased content of aspartic acid in the rice wine.

The rice wine is made through a complex fermentation process involving several kinds of microbes, including saccharifying enzyme to hydrolyze starch and dextrin to increase saccharide favorable to the growth of microbes in distiller's yeast, and alcohol fermentation with saccharomycete and mycete to form special flavor of rice wine. The inventor guesses that different sterilization methods have different effects on metabolites of microorganisms and complex reactions among components in the wine, such as ammonia carbonyl reaction, condensation reaction, decomposition reaction and the like, so as to generate a plurality of different flavor development substances, and the effects of the different flavor development substances on the flavor of the rice wine, which have synergistic effect and antagonistic effect or masking effect, are still needed to be further researched.

(V) samples obtained in examples and comparative examplesSensory evaluation

The evaluation group consisted of 10 members, and evaluated the appearance, aroma, taste and overall harmony of the glutinous rice wine, and the wine was rinsed with cold boiled water before tasting and tasted at a small mouth, and the evaluation criteria are shown in the following table.

TABLE 6 organoleptic evaluation standard table for glutinous rice wine

Sensory evaluation results are shown in the following table:

TABLE 7 sensory evaluation results

Item	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2	Comparative example 3
								Form and color	23.0	23.0	22.0	23.0	23.0	22.5	23.5
Fragrance and aroma	23.0	23.0	23.0	23.5	13.5	11.5	23.5
								Taste of the product	23.5	23.5	23.5	23.0	13.5	12.5	21.5
Wine body style	23.0	22.5	24.0	24.0	14.0	12.0	22.5
								Total score	92.5	92.0	92.5	93.5	64.0	58.5	91.0

As can be seen from the sensory evaluation results, the rice wine of the invention is obviously superior to the comparative example 1 and the comparative example 2 in terms of color, aroma, flavor and wine body style, and is close to the comparative example 3.

Sixthly, the samples obtained in the examples and the comparative examples are subjected to the detection of the sanitation indexes

TABLE 8 hygiene index test results

The total number of colonies was measured by GB4789.2-2016, and the number of coliforms was measured by GB 4789.3-2016. It can be seen that the rice wine obtained by the high-voltage pulse electric field sterilization treatment of the invention has the health index meeting the national standard and has the same effect as the heat sterilization, while the rice wine of the comparative example 3 has no sterilization and the health index does not meet the requirements.

(VII) detection of quality change in Normal temperature storage

The rice wine stored at normal temperature for a certain period of time is subjected to sensory evaluation by a professional evaluation panel, the sensory evaluation comprises changes in the aspects of shape, color, smell, taste and the like, if the color of the rice wine changes and the smell of the rice wine appears ozone taste, the quality of the rice wine is deteriorated, and the quality changes of the rice wine stored for different standing times are shown in the following table. And the physical and chemical properties of the rice wine stored for a certain time are detected, and the results show that the amino acid nitrogen, the organic acid, the total sugar, the amino acid content and the like in the rice wine prepared by the invention are relatively stable, and the organic acid content and the amino acid content in the heat-sterilized rice wine are obviously reduced after the rice wine is stored for 6 months because various components of the rice wine are subjected to complex changes during the storage period, and possibly high alcohol in the wine reacts with the organic acid to reduce the organic acid content.

TABLE 9 variation of Rice wine quality with storage time

Storage time

Example 1

Example 2

Example 3

Example 4

Comparative example 1

Comparative example 2

Comparative example 3

Storing for 10 days

Is normal

Begin to deteriorate

Storing for 30 days

Is normal

Deterioration of the surface

Storing for 3 months

Is normal

－

Storing for 6 months

Is normal

－

Storing for 12 months

Is normal

－

The invention discloses a novel rice wine product by optimizing a sterilization mode in a rice wine preparation process. The invention adopts high-voltage pulse electric field sterilization to sterilize wine, the pulse electric field can act on cell membranes of microorganisms to cause polarization perforation or direct discharge breakdown, thereby causing the cell contents of the microorganisms to seep out and die, effectively killing the microorganisms and simultaneously ensuring that the activity of sucrose invertase in the rice wine is not influenced, and the fresh rice wine meeting the standard of the fresh rice wine is prepared, thereby providing a new rice wine variety which can prolong shelf life and ensure fresh taste and rich nutritive value.

The above description is only exemplary of the invention and should not be taken as limiting, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the invention should be included in the scope of the invention.

Claims

1. A method for preparing raw rice wine by utilizing high-voltage pulse electric field sterilization is characterized by comprising the following steps:

1) processing glutinous rice to obtain cooked glutinous rice;

2. The method according to claim 1, wherein the parameters during sterilization in step 3) are set as follows: the electric field intensity is 30-40 kV/cm, the number of pulses is 50-100, the pulse width is 10-40 mu s, the pulse frequency is 500-1000 Hz, and the processing time is 100-150 mu s.

3. The method according to claim 1, further comprising the step of aerating the fermented wine after the sterilization treatment so that the concentration of the gas in the fermented wine is 2-6 g/L.

4. The method of claim 3, wherein the gas is CO₂、N₂Or CO₂And N₂Gas obtained by mixing according to a certain proportion.

5. The method as claimed in claim 1, wherein the cooked glutinous rice in the step 1) is prepared by: cleaning the sticky rice, soaking the sticky rice for 10-18h at room temperature, cooking the soaked sticky rice for 20-30min, and then showering and cooling the sticky rice to 30-35 ℃.

6. The method as claimed in claim 1, wherein the fermentation is terminated in step 2) when the alcoholic strength of the fermented wine is 6-14% vol, the total sugar content is 10-160g/L and the total acid content is 0.5-10 g/L.

7. The method according to claim 1, wherein the method for separating the fermented wine liquid in the step 2) comprises the following steps: and carrying out filter pressing or centrifugal separation on the fermentation liquor to obtain fermented liquor, and filtering the fermented liquor.

8. The method of claim 7, wherein the filtration is performed using a microporous membrane having a pore size of 0.30 to 0.50 μm.

9. A raw rice wine prepared by the method of any one of claims 1 to 8.

10. The raw rice wine of claim 10, wherein the raw rice wine has an alcohol content of 6 to 14% vol and sucrose invertase is positive.