CN112401196A

CN112401196A - Low-salt, low-acid and low-water-activity pickled radish as well as preparation method and application thereof

Info

Publication number: CN112401196A
Application number: CN202010921314.0A
Authority: CN
Inventors: 彭灯水; 王文建; 汤春梅; 闵锡祥; 徐柯; 李兰英; 喻淋英; 贺德瑞; 徐明利; 丁文军; 王艳丽; 颜正财
Original assignee: Jixiangju Food Co Ltd
Current assignee: Jixiangju Food Co Ltd
Priority date: 2020-07-24
Filing date: 2020-09-04
Publication date: 2021-02-26

Abstract

The invention relates to the technical field of food processing, in particular to pickled radish with low salt, low acid and low water activity, a preparation method and application thereof, and the pickled radish is characterized in that: fermenting radix Raphani with low salinity of 3-5% for 15-30 days; after the acidity reaches 0.3-0.5%, opening the pool to clean the radish vegetable embryos, transferring the radish vegetable embryos into a subsequent process of a high-cleanness production area, shaping and shredding or slicing or dicing the vegetable embryos, pressing and dehydrating the vegetable embryos to obtain vegetable embryos with the salinity of 3-5%, the water content of 80-84% and the water activity of 0.89-0.92, putting the vegetable embryos into the pool to enter a two-stage fermentation storage stage, and enabling the acidity to tend to be stable after the two-stage fermentation is carried out for 2-3 months. Desalting wastewater is not generated, and the salt usage amount and the production water consumption amount are reduced; meanwhile, the turnover rate of the fermentation tank is improved, and the usage amount of the fermentation tank is reduced; the fermented mature vegetable embryo can be directly used for producing radish seasoning pickle, can be stored for more than one year, and meets the requirement of stable supply of production raw materials of enterprises.

Description

Low-salt, low-acid and low-water-activity pickled radish as well as preparation method and application thereof

Technical Field

The invention relates to the technical field of food processing, in particular to pickled radish with low salt, low acid and low water activity, a preparation method and application thereof.

Background

The pickle is a traditional fermented food, and the radish is one of the main raw materials for producing the pickle and is also an important raw material for industrialized pickle production. The fresh radish raw material for producing the pickle is collected from 12 months to 1 month in the second year every year, and enterprises need to purchase and store the raw material required for production in one year in a purchasing period. In the traditional radish fermentation and storage process, radish pickle embryos are soaked in medium-high concentration bittern, are fermented to be mature, and are subjected to cleaning, sizing, desalting, squeezing and dewatering, seasoning and material mixing, filling and sterilizing and other seasoning procedures to be processed into pickle products meeting the edible habits of consumers, for example, the pickled radish pickle products including table pickles have the salinity of 2-6%, the acidity of 0.2-0.9% and the pH of 4.0-4.7.

The traditional radish fermentation and storage process is a medium-high salt fermentation and storage process, and generally adopts a one-time medium-high salt fermentation and storage process or a two-section medium-high salt fermentation process of one-section low salt fermentation and two-section medium-high salt storage after turning over a pool. The once medium-high salt fermentation storage process is characterized in that 10-15% of salinity is added once when radish raw materials are fermented and stored, the radish is fermented and matured after 10-15% of fermentation for 5-6 months, and the total acid reaches 0.6-1.5%. The two-stage fermentation process is characterized in that 3-6% of salinity is adopted in the first stage, fermentation is carried out for 1-2 months, the pond is turned over after the acidity reaches 0.4-0.7%, and then the fermentation and storage are carried out on 10-15% of medium-high salt in the second stage; after the second stage of fermentation for 4-5 months, the vegetable embryo is fermented and matured, and the acidity reaches 0.6-1.5%. The radish can be dehydrated by 20-30% in the first low-salt fermentation stage, and then enters the middle-high salt second-stage fermentation through the turning pool. The radish is fermented and matured by the medium-high salt fermentation storage process for 6-8 months, the yield of the vegetable embryo is 0.6-0.8 percent of fresh vegetable, 0.6-1.5 percent of total acid, 10-15 percent of salinity and 85-90 percent of vegetable embryo water. Because of the high salt content, the vegetable embryo can be stored for more than one year.

The seasoning pickle production process is that the mature fermented pickle blank is cleaned, shaped, desalted to 3-5%, squeezed and dewatered to 80-85%, and then enters the pickle seasoning production process no matter the one-time medium-high salt fermentation storage process or the two-stage medium-high salt fermentation process. 3-4 tons of fresh radishes and 0.3-0.6 ton of salt are required for producing each ton of pickled radish product, 9-12 tons of desalination waste water are produced, a large amount of fermentation tanks are required for storing radish raw materials, a large amount of salt is consumed, production waste water is produced, and a large amount of sewage treatment cost is required for treating the production waste water to reach the national environmental protection discharge standard.

In the fermentation stage, the salinity has obvious influence on the early stage of the fermentation of the pickle, and the change of the mass concentration of the salt causes the osmotic pressure of brine and the water activity inside the pickle to change, so that the strain structures in the fermentation process are different. The lactobacillus in the pickle with the addition of 2 percent of salt has the fastest breeding metabolism, has homotype fermentation and heterotype fermentation, and the pH value is reduced when the fermentation is finished but the pickle is not durable for storage. The addition of 5 percent of salt can better inhibit the propagation of fungi and escherichia coli; the addition of 8 percent of salt slows down the propagation and metabolism of lactic acid bacteria in the pickle, and has the technical problems of obviously weakening the heterotypic fermentation stage of the pickle, delaying the maturation period of the pickle and minimizing the utilization rate of sucrose.

With the development of food or related research, the method for controlling the growth of microorganisms and calculating the shelf life of food and medicines by using the water activity test has gradually become an important index for inspection in the industries of food, medicine, biological products, food, feed, meat products and the like. The water activity of a food product is an important factor in determining shelf life when temperature, pH and several other factors influence the rapid growth of microorganisms in the product. The water activity refers to a state in which water is present in the system, i.e., the degree of binding (degree of liberation) of water. The water activity Aw is defined as the ratio of the water vapor pressure P exhibited by a food at a certain temperature to the pure water vapor pressure Po at the same temperature, i.e.: aw is P/Po. Foods containing water and the like have different shelf-life stabilities due to their different water activities. The Aw is reduced, and the water is removed (drying, namely, drying storage refers to removing water in the food, so that the water activity of the food is reduced, the microbial activity, the enzyme activity and the chemical reaction are limited, and the purpose of long-term storage is achieved), the osmotic pressure is improved (salting, sugar making, concentration and the like) or the water state is controlled (low-temperature storage or quick freezing) and the like. Common salt has good permeability and can be dissociated into Na + and C1-in water, and the water activity value in the food is reduced by combining with polar water molecules with coulomb force.

Generally, foods with water activities above 0.85 require refrigeration or other measures to control pathogen growth. The food with the water activity of 0.60-0.85 is medium-water food, and the food does not need refrigeration to control pathogens, but has limited shelf life due to the spoilage caused by main yeasts and molds. For most food products having a water activity below 0.6, which have a longer shelf life and do not require refrigeration, these food products are referred to as low moisture food products.

Each type of microorganism requires a certain water activity for growth, and a specific microorganism can grow only when the water activity of food is greater than a certain critical value. Each microorganism had the lowest, best, highest water activity for its growth, as shown in figure 1. The lactic acid bacteria and the yeast are facultative aerobic bacteria, the lactic acid bacteria are active under the anaerobic condition, but the water activity needs to be more than 0.94; the yeast can resist water activity of below 0.88-0.92, but is more actively metabolized under aerobic conditions; the mold resistance of rhizopus, mucor and the like is aerobic bacteria, and the mold can be metabolized and activated under aerobic conditions.

Yeasts and molds can grow at low moisture, but 0.85 is a safety margin for pathogen growth. When the water activity is less than 0.60, most microorganisms cannot grow. In addition, the water activity influences the mobility of the substrates of the enzymatic reaction on the one hand and the conformation of the enzyme on the other hand for the enzymatic reaction. When the water activity of most of the enzyme substances in the food system is less than 0.85, the activity is greatly reduced, such as amylase, phenol oxidase, polyphenol oxidase and the like. At lower water activities the water in the food combines with the hydroperoxide making it less prone to oxygen free radicals leading to chain oxidation termination, and when the water activity is increased above 0.4 the oxygen dissolution in the food is increased. Oxidation is accelerated and when the water activity is greater than 0.8 the reactants are diluted, oxidation is reduced. Maillard reaction: the substrate is diluted when the water activity is greater than 0.7. And (3) hydrolysis reaction: since water is a reactant of the hydrolysis reaction, the rate of the hydrolysis reaction increases as the water activity increases.

In the preservation method of the fresh dried beancurd sticks in the specification of the Chinese patent CN201510606249.1, the water activity of the preserved fresh dried beancurd sticks is 0.75-0.8, natamycin is used as a preservative, and vacuum packaging and microwave sterilization technology are adopted. The fresh dried beancurd sticks are prepared by the following steps: soaking soybeans in 4-6 times of water at normal temperature for 8-10 h, taking out the soybeans, draining, adding 4-6 times of water into the soybeans, and grinding the soybeans into thick liquid to obtain raw soybean milk, wherein the pH value of the raw soybean milk is 6.7-6.9; and boiling the soybean milk, keeping the soybean milk boiling for 2-4 min, adding a water activity reducing agent and natamycin in the boiling process, keeping the temperature of the soybean milk at 78-82 ℃, and uncovering the bamboo to obtain the fresh dried beancurd sticks. The water activity reducing agent is agar, gelatin and citric acid, the addition amount of the gelatin in the soybean milk is 0.4-0.6 g/100mL, the addition amount of the agar is 0.4-0.6 g/100mL, and the addition amount of the citric acid is 0.015-0.018 g/100 mL. By reducing the water activity of the fresh dried beancurd sticks and using proper packaging materials and sterilization technology, the fresh dried beancurd sticks can be preserved for 46-52 days at normal temperature, and have good taste, texture and smell except for slightly deepened color.

The method for improving the comprehensive performance of the vegetable paper in the specification of the Chinese patent CN201410634601.8 mainly comprises the steps of firstly carrying out pretreatment such as selection, washing, slicing, blanching, enzyme deactivation, curing (5-10 min), color protection and the like on vegetable raw materials, then draining until no obvious water drops exist on the surface, mixing with a precipitation activity regulator and a forming agent, pulping (3-5 min), degassing, drying until the moisture content is 20-30%, uncovering, cutting and continuously drying (40-60 ℃) until the moisture content is 10-20%. Due to the adoption of the water reducing and activity separating agent, the water content of the vegetable paper can be 10-20%, the water activity is 0.55-0.70, and the vegetable paper has good palatability and can ensure that the quality is not obviously deteriorated in a long time (6-12 months). The water content of the vegetable paper is improved, the water activity can be kept at a safe level, and the palatability and the safety of the vegetable paper are improved. The added water-reducing activity-reducing agent is salt, cane sugar, glucose, lactose, fructose-glucose syrup and trehalose which are used singly or in combination, and the addition amount of the water-reducing activity-reducing agent is 5-15% of the wet weight of fruits and vegetables.

However, the manufacturing technology of the pickled radish is different from that of the fresh bean curd sticks and the vegetable paper, and the two products have the defects of various types of added auxiliary materials and additives, no environmental protection during eating and complex process. Drying is also carried out in the modes of natural drying, drying by drying equipment and the like, and the energy consumption cost is high; the natural drying efficiency is low, and the method is not suitable for industrial production. The conditions influencing the taste and the storage period are more, and the taste and the original taste of the raw materials are difficult to store; it is not prepared and stored by simply utilizing the characteristic of water activity.

Disclosure of Invention

In order to solve the technical problems, the original thought and technology for making pickled vegetables are broken through, the invention provides pickled radish with low salt, low acid and low water activity and a preparation method thereof, and a brand-new pickled radish fermentation storage method in the field of pickled vegetables, namely pickled radish pickle, adopts two stages of fermentation processes with the same salinity of radish, does not generate desalting wastewater in the process, and reduces the use amount of salt and water for production; in the production process, only radish and salt are used as raw materials, and additives and auxiliary materials are not added, so that the radish and salt bread is environment-friendly and safe to eat; meanwhile, the turnover rate of the fermentation tank is improved, the usage amount of the fermentation tank is reduced, the production cost is greatly reduced, and the economic benefit is improved; the produced pickle can be stored for more than one year, and the requirement of stable supply of production raw materials of enterprises is met; can be directly used for the production of radish seasoning pickle, more flavor substances in the fermentation process of the pickle are reserved, and the taste is sour, fragrant, crisp and tasty.

The pickled radish with low salt, low acid and low water activity, which solves the technical problems, comprises radish embryos and is characterized in that: the vegetable germ has salinity of 3-5%, water content of 80-84%, water activity of 0.89-0.92, acidity of 0.4-0.7%, and pH of 3.8-4.4.

In the optimization scheme, the salinity is 4.1 percent, the water content is 83 percent, the water activity is 0.9, the acidity is 0.43 percent, and the pH value is 4.2-4.4.

In a further optimization scheme, the vegetable germ has the salinity of 4%, the water content of 82%, the water activity of 0.91, the acidity of 0.5% and the pH value of 4.1.

The putrefactive deterioration of food is usually caused by the action of microorganisms and biochemical reactions, and the growth and reproduction of any microorganism and most biochemical reactions require water as a solvent or medium. The invention utilizes multiple barriers of pH value and water activity to ensure stable and safe storage of the pickled radish.

The invention discloses a preparation method of pickled radish with low salt, low acid and low water activity, which comprises the following steps:

(1) preparing raw materials: selecting healthy fresh radish, cleaning, and removing putrefaction, impurities, etc.;

(2) one-stage fermentation: fermenting fresh radish 3-5% at low salinity for 15-30 days, pickling with low salt to make the radish rapidly ferment in saline water to produce acid, reduce pH in the fermentation system, and inhibit putrefactive flora such as Escherichia coli and Bacillus. The total acid content is 0.2-0.5%.

(3) After the acidity is 0.3-0.5% and the pH is 4.0-4.5, opening the pool to clean the radish vegetable embryo, and transferring to the subsequent process of the high-cleanness production area;

(4) shaping and dehydrating: shaping, shredding, slicing or dicing the vegetable embryos, and then squeezing and dehydrating the vegetable embryos;

(5) two-stage fermentation and storage: two-stage fermentation and storage: and (3) putting the dehydrated vegetable embryos into a pool, pressing and compacting, pressing and sealing the pool, entering a two-stage fermentation storage stage, and entering the next processing step after the second-stage fermentation time is 2-3 months.

And (4) putting the dehydrated vegetable embryos into a pool, and pressing and compacting the vegetable embryos to isolate oxygen in the external air. The pressing pool enters a two-stage fermentation storage stage, and the vegetable embryo tends to be stable in the acidity of 0.4-0.7% and the salinity of 3-5% after 2-3 months of the second-stage fermentation. Two-stage fermentation and storage, wherein the water content in a fermentation system is mainly reduced to form a dry state fermentation environment, the activity of functional microorganisms such as lactobacillus and saccharomycetes in the fermentation system is greatly inhibited at a low water activity of 0.89-0.92 and the pH of a vegetable embryo is 4.2-4.4, and the two-stage fermentation enters a low activity process, wherein the biochemical stale flavor reaction of the metabolic products of the functional microorganisms is carried out. The mature vegetable embryo obtained by the two-stage fermentation is directly used for the subsequent seasoning production of the pickle.

And (3) fermenting the fresh radish 5% in the step (2) at low salinity for 25 days.

In the step (4), the vegetable germ has the salinity of 3-5%, the acidity of 0.3-0.5%, the pH value of 4.0-4.5, the water content of 80-84% and the water activity of 0.89-0.92.

In the step (5), the acidity after the second stage of fermentation is 0.4-0.7%, the pH value is 3.8-4.4, and the salinity is 3-5%.

The first-stage fermentation and the second-stage fermentation are stored at normal temperature.

The pickled radish embryo is directly used for the production of pickled radish without desalting, and enters the subsequent seasoning or other processing steps.

The invention obtains the radish pickle needed correspondingly by integrally controlling the salinity, water activity and acidity of the pickle embryo, and each index and the corresponding value are supplemented with each other to play a role in synergism. When low salt is adopted in the prior art, high acid is utilized for fermentation, and the low salt fermentation of the pickle is beneficial to the metabolism and acid production of lactic acid bacteria in a fermentation system and has higher acidity. But the high-acidity environment is not beneficial to vegetable storage, vegetable fiber and pectin tissues are more dissolved and degraded in the high-acidity environment, and the taste brittleness of the pickled vegetables is reduced; on the other hand, the pickle with high acidity and suitable acidity has fewer consumer groups and is not easily accepted by most consumers. The specific analysis is as follows:

when the pickle is only low salt: the low-salt pickle fermentation can be carried out, a large amount of juice can be exuded from vegetables under the osmotic pressure of salt, and the vegetables can be immersed in the vegetable juice to form wet fermentation; with the lapse of fermentation time, the acidity of the vegetable embryo gradually rises, and when the pickled radish is fermented completely, the acidity can reach 2%, under the condition of high acidity, the brittleness of the vegetable embryo tissue can be reduced, and the low salt can not stabilize the fermentation quality of the pickled vegetable raw material. The food processing industry needs to pay attention to the stability of raw materials and price, and the seasonal nature of vegetable planting determines that enterprises need to purchase raw materials which are stored for one year production in the current season of vegetable planting. The vegetable fermentation low-salt process cannot meet the requirement of enterprises on storing raw materials.

When the kimchi is only of low water activity: storing vegetables at low water activity, such as traditional dried vegetables; the dried vegetables are obtained by natural drying, drying by drying equipment and the like, and the natural drying efficiency is low, so that the method is not suitable for industrial production; the drying equipment is used for drying, and the energy consumption and the cost are high. The low water activity of the pickle does not reflect the low salt characteristic thereof, and the characteristic of the invention is not highlighted. High salt and low water activity, and needs to be desalted by using production water in production, so that the salinity of the vegetable germ is reduced to meet the requirement of consumers.

When the kimchi is only of low acidity: the salty taste of the salt is one of the main characteristics of the flavor of the pickle. The low acidity fermentation of the pickle is also the shallow fermentation of the pickle, the acidity is lower, and the pickle meets the taste requirements of a part of consumers; the low-acid fermentation can be obtained by controlling the fermentation time, but the fermentation process of the vegetable embryo does not stop naturally.

When the kimchi is low-salt, low-moisture active: the pickle is a vegetable lactobacillus fermentation product, the lactobacillus fermentation makes the vegetable embryo acidic, and the important characteristic of the pickle is that the vegetable embryo is endowed with sourness and taste. The higher the acidity of the vegetable embryo, the safer the storage period of the vegetable embryo is under the premise of low salt and low water activity. However, the taste of the high-acidity vegetable germ is not the taste required by consumers, especially for table-meal seasoning pickles.

Effect when kimchi is low in acid, low in moisture activity: the pickle is in a low-acid state and can be obtained by fermenting pickle endosperm acidobacteria in a shallow layer, and the pickle is easier to realize low salt and low water activity in a high-salt state, but the pickle embryo stored in the mode needs to be desalted to low salt by using production water in the subsequent processing. A large amount of desalted wastewater is generated, which is not beneficial to the sustainable development of the pickle industry.

Effect when kimchi is low-salt, low-acid: production cannot be achieved. The low acidity fermentation of the pickle is also the shallow fermentation of the pickle, the acidity is lower, and the pickle meets the taste requirements of a part of consumers; the low-acid fermentation can be obtained by controlling the fermentation time, but the fermentation process of the vegetable embryo does not stop naturally.

The pickled radish provided by the invention has good effects by fully utilizing the integral coordination, interaction and promotion of salinity, water content, water activity, acidity and pH of the pickled radish embryo. In the whole process, only radish and salt are used, no additional auxiliary materials and additives are added, high-cost equipment is provided, and the radish and salt seasoning is safe and environment-friendly to eat.

The method of the invention needs 3 to 4 tons of fresh radish and only needs 0.09 to 0.2 ton of salt for producing each ton of radish seasoning pickle, and the salinity is basically the same in the two stages of fermentation, thereby not generating desalination waste water, reducing the salt usage amount and the production water usage amount, improving the turnover rate of the fermentation tank and reducing the usage amount of the fermentation tank. The radish pickle embryos are fermented for 3-4 months to be mature, the fermented pickle embryos can be directly used for producing radish seasoning pickle after being taken out of a pool, desalting is not needed, more flavor substances in the pickle fermentation process are reserved, and the radish pickle has sour, fragrant and crisp mouthfeel. The preparation method is very simple, strong in operability, low in cost and high in economic benefit.

The radish embryo fermented and matured in the invention has bright yellow color, uniform shape, strong fermentation smell, pleasant acid and fragrance and crisp mouthfeel. The content of acidovorax facilis in the vegetable endosperm of the radish reaches 1.6X107-8CFU/g and the content of yeast reaches 2.1X105-6CFU/g in the later stage of the first fermentation stage, and the content of lactic acid and yeast is greatly reduced through the procedures of cleaning, sizing, squeezing, dewatering and the like; the acid bacteria content of the endosperm of the vegetable at the initial stage of the secondary low-salt, low-moisture and low-acid fermentation is 106CFU/g, and the yeast content is 104 CFU/g. Fermenting and maturing radish vegetable embryos, and taking the radish vegetable embryos. The product can be stored for more than one year, meets the requirement of stable supply of production raw materials of enterprises, and can be used all year round.

Drawings

FIG. 1 minimum Water Activity Table necessary for growth of microorganisms in the present invention

FIG. 2 is a flow chart of the production process of the present invention

Detailed Description

The invention will be further illustrated with reference to specific embodiments:

example 1

A low-salt, low-acid and low-water-activity pickled radish comprises radish embryo with salinity of 3%, water content of 80%, water activity of 0.89, acidity of 0.4%, and pH of 4.4.

Example 2

A low-salt, low-acid and low-water-activity pickled radish comprises radish embryo with salinity of 5%, water content of 84%, water activity of 0.92, acidity of 0.7%, and pH of 3.9.

Example 3

A low-salt, low-acid and low-water-activity pickled radish comprises radish embryo with salinity of 3.8%, water content of 82%, water activity of 0.9, acidity of 0.55%, and pH of 4.1.

Example 4

A low-salt, low-acid and low-water-activity pickled radish comprises radish embryo with salinity of 4%, water content of 83%, water activity of 0.91, acidity of 0.5%, and pH of 4.1.

Example 5

A low-salt, low-acid and low-water-activity pickled radish comprises radish embryo with salinity of 4.5%, water content of 81%, water activity of 0.91, acidity of 0.45%, and pH of 4.2.

Example 6

A low-salt, low-acid and low-water-activity pickled radish comprises radish embryo with salinity of 3.5%, water content of 82%, water activity of 0.9, acidity of 0.6%, and pH of 4.0.

Example 7

A low-salt, low-acid and low-water-activity pickled radish comprises radish embryo with salinity of 4.1%, water content of 83%, water activity of 0.9, acidity of 0.43%, and pH of 4.3.

Example 8

The preparation method of the pickled radish with low salt, low acid and low water activity comprises the following specific steps:

(1) preparing raw materials: selecting healthy qualified fresh radishes, cleaning, and removing putrefaction, impurities and the like;

(2) one-stage fermentation: fermenting fresh radish at 3% low salinity for 30 days, and pickling with low salt to rapidly ferment the radish in saline water with lactobacillus to produce acid. The radish is fermented in the first stage, on one hand, the radish rapidly discharges water under the osmotic pressure of salt, and 3-5% of salinity can promote lactobacillus to rapidly grow, ferment and produce acid, and inhibit and kill other spoilage microorganisms; on the other hand, the short one-stage fermentation time and the low acidity are more sugar left by the fermentation of the lactic acid bacteria and the yeast in the fermentation system in the second fermentation storage stage. The total acid was 0.5%.

(3) After the acidity is 0.5%, opening the pool to clean the radish vegetable embryos, and transferring to the subsequent process of a high-cleanness production area; the acidic environment and the low water activity can prevent putrefactive microorganisms from growing and propagating in the radish, and the low water activity can enable lactic acid bacteria and saccharomycetes to become the dominant microbial flora in a radish fermentation system, thereby being beneficial to the formation of fragrant substances such as esters, aldehydes and the like.

(4) Shaping and dehydrating: shaping, shredding, slicing or dicing the vegetable embryo, and then squeezing and dehydrating the vegetable embryo, wherein the salinity of the vegetable embryo is 3%, the water content is 80%, the water activity is 0.89, the acidity is 0.5, and the pH is 4.0; the space ratio of the vegetable embryo from the fresh radish to the two-stage fermentation is 0.25-0.3, which can reduce the volume requirement of the fermentation tank by 60%.

(5) Two-stage fermentation and storage: and (3) putting the dehydrated vegetable embryos into a pool, pressing and compacting, sealing the pool by pressing, and entering a two-stage fermentation storage stage, wherein after 2-3 months of second-stage fermentation, the acidity is 0.4%, the salinity is 3%, and the pH is 3.8, and then entering the next processing step. Wherein the fermentation is carried out in a sealed tank with salt or water.

The stored or fermented mature vegetable embryo is directly used for the subsequent seasoning production of the pickle. Wherein the first-stage fermentation and the second-stage fermentation are carried out at normal temperature. The prepared radish pickle embryo is directly used for the production of radish pickle without desalting, and enters the subsequent seasoning or other processing steps. Such as opening a pool to take dishes, seasoning and filling in a workshop, sterilizing and cooling and the like.

And (2) putting the shaped and dehydrated vegetable embryos into a fermentation tank for two-stage fermentation and storage, wherein the vegetable embryos are not salted any more but are compacted layer by layer in the process of putting the vegetable embryos into the tank, flattening and compacting the surface of the tank after the vegetable filling amount of the fermentation tank reaches 0.9-0.95 volume, laying two layers of clean food-grade plastic films on the surface of the tank, wherein the periphery of each film is 40-60cm higher than the four sides of the fermentation tank, sealing the tank by salt squeezing or clean drinking water squeezing, and laying salt with the thickness of 20-35cm or injecting water with the depth of 30-50cm on the surface of the tank to achieve the purpose of compacting the surface of the tank. The surface of the water seal tank is covered with a layer of lightproof plastic film to protect the vegetable embryo from light.

Example 9

Selecting healthy qualified fresh radish, cleaning, removing putrefaction and impurities, fermenting at 5% salinity for 25 days, wherein the acidity of the vegetable embryo is 0.45%, and the salinity is 4.2%. The radish vegetable embryo is transferred into a high-cleanness production area for cleaning, shaping, squeezing and dehydrating, wherein the water content of the vegetable embryo is 83%, the salinity is 4.1%, the acidity is 0.43%, the water activity is 0.90, and the pH value is 4.2. And (2) putting the shaped and dehydrated vegetable embryos into a fermentation tank for two-stage fermentation and storage, wherein the vegetable embryos are not salted any more in the process of putting the vegetable embryos into the fermentation tank and are compacted layer by layer, after the vegetable filling amount of the fermentation tank reaches 0.9-0.95 volume, flattening and compacting the surface of the tank, laying two layers of clean food-grade plastic films on the surface of the tank, wherein the periphery of each film is 40-60cm higher than the four sides of the fermentation tank, and sealing the tank by salt squeezing, wherein the thickness of the salt is 20 cm. After the fermentation for 3 months, the vegetable embryo is fermented and matured, and can be directly used for seasoning production of the pickled vegetables.

After the two-stage fermentation is carried out for 2-3 months, the radish vegetable embryo is mature in fermentation, sour, fragrant, crisp, stable in acidity, and reaches 0.3-0.7%, the salinity is 3-5%, and the water content is 80-84%. The pickled radish blanks can be directly used for producing radish seasoning pickle after opening the tank, the radish blanks stored by two-stage fermentation can be stored for more than one year, water desalination is not needed in the production process of the radish pickle, and the use amount of salt, the volume requirement of the fermentation tank and the production water consumption are reduced.

Example 10

Otherwise, as in example 8, the fresh radish was fermented in a low salinity of 5% for 15 days at an acidity of 0.2% in one stage of fermentation. In the shaping and dehydrating step, the salinity of the vegetable embryo is 5 percent, the water content is 84 percent, the water activity is 0.92, the acidity is 0.5 percent, and the pH value is 4.2. The acidity, salinity and pH of the fermentation medium are respectively 0.7%, 5% and 4.0.

Example 11

The rest is as in example 8, wherein the fresh radish in the first stage of fermentation is fermented at 4% low salinity for 20 days and has 3% acidity. In the shaping and dehydrating step, the salinity of the vegetable embryo is 3.8 percent, the water content is 81 percent, the water activity is 0.91, the acidity is 0.4 percent, and the pH value is 4.1. The acidity, salinity and pH of the fermentation medium are respectively 0.5%, 3.8% and 3.9.

Example 12

Otherwise, as in example 8, the fresh radish in the first stage of fermentation was fermented at 3.5% low salinity for 18 days with 0.4% acidity. In the shaping and dehydrating step, the salinity of the vegetable embryo is 3.2 percent, the water content is 83 percent, the water activity is 0.92, the acidity is 0.35 percent, and the pH value is 4.1. The acidity, salinity and pH of the fermentation medium are respectively 0.5%, 3.2% and 3.9.

Example 13

Otherwise, as in example 8, the fresh radish in the first stage of fermentation was fermented at 4.5% low salinity for 28 days with acidity of 0.45%. In the shaping and dehydrating step, the salinity of the vegetable embryo is 3-5%, the water content is 80-84%, the water activity is 0.89-0.92, the acidity is 0.3-0.5%, and the pH value is 4.2. The acidity, salinity and pH of the fermentation medium are 0.55%, 3.8% and 4 respectively.

The indexes in the preparation method are slightly different from those of the final product, and the specific indexes are based on actual production and are all effective when finally falling into the given index range.

The radish embryo of the invention has good effects of fragrance, taste, brittleness, microorganism and the like after being stored for a certain time, and the table 1 is as follows:

TABLE 1 sensory evaluation and microbial changes of turnip dish embryos at various storage periods

Sensory evaluation was performed on 5 points: "very good" means 5 points, "better" means 4 points, and "general" means 3 points, and "bad" means 2 points or less. )

As can be seen from the above table 1, the flavor of the radish embryo tends to be stable from 3 months to 12 months, and the results are shown in that the dimensional sensory evaluation values of color, aroma, brittleness, comprehensive taste and the like are between 4.1 and 4.5, and are superior to the sensory evaluation values of 1 month in storage time. The lactobacillus content in the vegetable embryo fermentation system is 10 in order of magnitude within 1-6 months⁶CFU/g, reduced to 10 in 12 months⁵CFU/g; the yeast content is 10 in 1 month and 12 months⁴CFU/g, other intermediate storage period tests are of the order of 10⁴CFU/g. The change of the microorganisms in the vegetable embryo system in the storage and fermentation stage is a dynamic change process, and the fermentation activity of the lactobacillus in the storage period is stable on the whole.

Test No.)

1 ten thousand tons of radish seasoning pickle finished products are produced every year, and 3.5 ten thousand tons of fresh radishes are needed. The experimental group, the control group 1 and the control group 2 were set as follows:

control group 1: radish raw materials are fermented and stored at 12% salinity according to the traditional medium-high salinity fermentation and storage process, 4200 tons of salt is needed at the one-time 12% salinity, and 392 fermentation ponds with the volume of 100 tons are needed.

Control group 2: the traditional two-stage fermentation process of firstly fermenting with 5% salt and then fermenting with 12% high salt in two stages needs 3900 tons of salt and 300 fermentation tanks with the volume of 100 tons.

Experimental groups: in example 9, 1750 tons of salt are needed for one-stage fermentation, and the storage volume of the fermentation tank can be reduced to less than 200 for 100 tons.

TABLE 21 different fermentation storage process Material requirement and vegetable embryo sensory evaluation of ten thousand tons of pickled radish products

(note: the two-stage fermentation process is a fermentation storage process with 5% of salt and 12% of high salt in the two stages, and the yield of the primary low-salt fermented radish vegetable embryo is 0.7. the sensory evaluation includes comprehensive taste of the fermented radish vegetable embryo, 11 people participate in the process, and the sensory evaluation is a Sichuan pickled vegetable sensory evaluation committee which adopts 5 points, namely 'very good' takes 5 points, 'better' takes 4 points, 'general' takes 3 points, 'bad' takes 2 points and the following points.)

As can be seen from the table 2, compared with the traditional fermentation process, the method disclosed by the invention has the advantages that the use amount of the salt is reduced by more than 60%, the utilization rate of the fermentation tank is improved, the required volume of the fermentation tank is reduced by more than 40%, the desalted wastewater is not generated, the production water is reduced by more than 60%, and the comprehensive taste sensory evaluation of the vegetable embryo greatly exceeds the vegetable embryo flavor of the traditional fermentation mode, so that the method is an environment-friendly, energy-saving and efficient fermentation and storage process for the pickled radish.

In the control group 1 and the control group 2, the salinity of fermented mature vegetable embryo and the total acid are 12 percent, and the pickled vegetable is subjected to cleaning, sizing, desalting to 4 percent of salinity, squeezing and dehydrating to 85 percent of water, and then the pickled vegetable enters the seasoning process. 10 tons of water are consumed for the production of 10 ten thousand tons of desalination wastewater per ton of the produced pickle product. The pickled vegetable embryo which is fermented to be mature in high salt in radish can enter the pickled vegetable seasoning process after being cleaned, shaped, desalted and squeezed for dehydration, a large amount of desalted wastewater is generated, and the flavor substances such as acids, esters and the like generated in the pickled vegetable fermentation process are lost in the desalting process, so that similar flavor substances are required to be added in the pickled vegetable seasoning production process. The production process of the invention has no desalting process, does not produce desalting wastewater, furthest retains flavor substances such as ester flavor, aldehyde flavor and the like of the fermentation of the pickle lactobacillus and the later-stage composite fermentation of the saccharomycetes and the lactobacillus, and has sour, fragrant, crisp and tasty mouthfeel. The pickled vegetable embryo obtained by the radish low-salt, low-salt and low-water-activity fermentation process method can be directly used for workshop seasoning production, and no flavoring agent such as acid is required to be added, so that pickled vegetable fermented flavor substances are better preserved.

The method comprises the steps of producing acid by low-salt primary fermentation of radish, cleaning, shaping, squeezing and dewatering, and then putting the radish embryo into a pool for secondary fermentation, wherein the pool needs to be compacted and sealed. The secondary fermentation stage of radish vegetable embryo is that under anaerobic condition, the salinity of vegetable embryo is 3-5%, the acidity is 0.3-0.5, the pH is 4, 0-4.5, the water content is 80-84%, and the lower water activity is 0.89-0.92, so that the comprehensive hurdle effect for inhibiting the fermentation of lactobacillus and yeast is formed. The aerobic mould can not gather to grow and propagate.

Experiment three

After being fermented for 30 days at 5% salinity, fresh radish is cleaned, drawn, shaped, squeezed and dehydrated, and then enters a pool again to enter a secondary low-salt, low-acid and low-moisture fermentation pool.

TABLE 3 physicochemical data of the Secondary fermentation of turnip vegetable embryos into the tank

TABLE 4 physicochemical data of the secondary fermentation of radish embryos at different periods

From the physicochemical data of the radish vegetable embryos subjected to secondary fermentation in different periods in the tables 3 and 4, it can be seen that the acidity of the radish vegetable embryos reaches about 0.40% after fermentation for 90 days, and the acidity of the radish vegetable embryos is basically stable from 120 days to 360 days and is between 0.4% and 0.5%. The final fermentation acidity of the radish vegetable embryo by the process is obviously lower than that of the radish vegetable embryo by 0.6-1.5% by the traditional fermentation process. After the radish vegetable embryos are subjected to secondary fermentation for 90 days, the vegetable embryos tend to be mature through fermentation, and the vegetable embryos can be used for production.

While the foregoing shows and describes the fundamental principles and principal features of the invention, together with the advantages thereof, the foregoing embodiments and description are illustrative only of the principles of the invention, and various changes and modifications can be made therein without departing from the spirit and scope of the invention, which will fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A low-salt, low-acid and low-water-activity pickled radish comprises radish embryos, and is characterized in that: the vegetable germ has salinity of 3-5%, water content of 80-84%, water activity of 0.89-0.92, acidity of 0.4-0.7%, and pH of 3.8-4.4.

2. The method of claim 1, wherein the pickled radish with low salt, low acid and low water activity is prepared by the following steps: the salinity of the vegetable germ is 3.8 percent, the water content is 82 percent, the water activity is 0.9, the acidity is 0.55 percent, and the pH value is 4.2-4.4.

3. The method of claim 1, wherein the pickled radish with low salt, low acid and low water activity is prepared by the following steps: the vegetable germ has salinity of 4%, water content of 83%, water activity of 0.91, acidity of 0.5% and pH of 4.1.

4. The method for preparing a low-salt, low-acid, low-water-activity kimchi of radish according to any one of claims 1 to 3, comprising: the method comprises the following steps:

(1) preparing raw materials;

(2) one-stage fermentation: fermenting fresh radish 3-5% at low salinity for 15-30 days;

(3) opening the pool to clean the radish vegetable embryo after the acidity is 0.3-0.5%;

(4) shaping and dehydrating: shaping, shredding, slicing or dicing the vegetable embryos, and then squeezing and dehydrating;

(5) two-stage fermentation and storage: and (3) putting the dehydrated vegetable embryos into a pool, pressing and compacting, pressing and sealing the pool, entering a two-stage fermentation storage stage, and entering the next processing step after the second-stage fermentation time is 2-3 months.

5. The method of claim 4, wherein the pickled radish with low salt, low acid and low water activity is prepared by the following steps: and (3) fermenting the fresh radish 5% in the step (2) at low salinity for 25 days.

6. The method of claim 4, wherein the pickled radish with low salt, low acid and low water activity is prepared by the following steps: in the step (4), the vegetable germ has the salinity of 3-5%, the acidity of 0.3-0.5%, the pH value of 4.0-4.5, the water content of 80-84% and the water activity of 0.89-0.92.

7. The method of claim 4, wherein the pickled radish with low salt, low acid and low water activity is prepared by the following steps: in the step (5), the acidity after the second stage of fermentation is 0.4-0.7%, the pH value is 3.8-4.4, and the salinity is 3-5%.

8. The method for preparing a low-salt, low-acid, low-water-activity kimchi of radish according to any one of claims 4 to 7, wherein: the first-stage fermentation and the second-stage fermentation are stored at normal temperature.

9. The use of a low-salt, low-acid, low-water-activity kimchi of radish according to claim 1, wherein: the pickled radish embryo is directly used for the production of pickled radish without desalting, and enters the subsequent seasoning or other processing steps.