Secondary fermentation process of preserved szechuan pickle

Abstract

The invention relates to the technical field of preserved szechuan pickle pickling, and discloses a preserved szechuan pickle secondary fermentation process which comprises the following steps: S1, primary fermentation of mustard: laying mustard and table salt in layers, sealing, compacting and pickling to obtain primary fermented mustard for later use; s2, extracting lactic acid bacteria: taking pickled Chinese cabbage juice generated during primary fermentation of leaf mustard, inoculating the pickled Chinese cabbage juice into a culture medium, and selecting purified strains; s3, screening lactic acid bacteria: inoculating and culturing the purified strains, selecting the strains which grow vigorously and are high in acid production capacity, then inoculating the strains to a mustard sample, carrying out a secondary fermentation test, and selecting the strains which are high in sensory evaluation and are used for the mustard; and S4, secondary fermentation of the mustard: inoculating strains with high sensory evaluation to the primarily fermented mustard, adding a sugar aqueous solution, sealing, and carrying out secondary fermentation at normal temperature to obtain the preserved szechuan preserved szechuan preserved szechuan preserved szechuan preserved szechuan preserved szechuan preserved szechuan preserved szechuan. The prepared preserved szechuan pickle is bright in dish color, golden yellow, good in crispness and tenderness, rich in fragrance, pure in flavor, sour, sweet and delicious.

Description

Technical Field

[0001] The invention relates to the technical field of pickled mustard tuber, in particular to a secondary fermentation process of mustard tuber. Background Art

[0002] Zhacai has a special sour and salty taste, is crisp and refreshing, and can be used as a side dish, stir-fry, and soup. It can promote digestion and increase appetite, and is deeply loved by people. Among them, mustard is named for its pungent smell. Mustard contains glucosinolates, which produce volatile isothiocyanate compounds, thiocyanate compounds and their derivatives after hydrolysis, and have a special flavor and spicy taste. Mustard has the effects of improving constipation and refreshing the mind, but mustard usually needs to be pickled and fermented before it can enter the dining tables of thousands of households.

[0003] A Chinese patent discloses a pickling process for fresh and fragrant mustard greens (Announcement No. CN104996944A). The patented technology involves washing fresh mustard greens, exposing them to the sun, and initially pickling them to remove moisture and spicy flavorings; turning the dehydrated mustard greens into a jar, and re-stacking them in layers at a mass ratio of mustard greens to salt of 100:20; then pouring in seasoning water and soy sauce for pickling; turning the pickled mustard greens into a jar, pouring out the water, dissolving the salt at the bottom of the jar with cold boiled water, placing the mustard greens into the jar, filling the jar with cold boiled water, and pickling for 60 days; during the pickling process, opening the jar cover during the day and exposing them to the sun; sealing the jar cover at night; then turning the jar over for the third time, and then turning the jar over once every 10 days, for a total of 10-14 times, to obtain fresh and fragrant mustard greens, but their smell and taste are not good. Summary of the invention

[0004] The purpose of the present invention is to provide a secondary fermentation process of mustard tuber so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A secondary fermentation process of mustard tuber, comprising the following steps:

[0007] S1. Primary fermentation of mustard: fresh mustard is selected, and a layer of mustard and a layer of salt are spread in a fermentation tank, which is sealed and compacted. After pickling for 45 to 60 days, the mustard is rinsed, desalted, squeezed and dehydrated to obtain primary fermented mustard for use;

[0008] S2. Lactic acid bacteria extraction: Take the sauerkraut juice produced by the first fermentation of mustard, inoculate it into MRS liquid culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 36-48h, centrifuge it, and take the suspended bacteria; dilute the suspended bacteria 100 times, and then inoculate it into CaCO at a volume ratio of 1:10. 3-MRS medium, mix thoroughly and culture at 37°C for 36-48h, select the larger colonies and streak them on MRS solid medium until colonies with uniform morphology and size are cultured, thus obtaining the purified strain;

[0009] S3. Screening of lactic acid bacteria: After diluting the purified strain 100 times, inoculate it into MRS liquid culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 36-48h, select strains with strong growth and acid production ability, and measure the optimal pH value for strain growth; then take mustard samples from the first fermented mustard, inoculate the strains with strong growth and acid production ability into the mustard samples at a mass ratio of 2%-3%, seal them, ferment them for 5-7d, obtain mustard samples after the second fermentation, perform sensory evaluation on them, and select strains for mustard with high sensory evaluation;

[0010] S4, secondary fermentation of mustard: dissolve sucrose in water at a mass ratio of (1-3):100 to obtain a sugar solution, add the sugar solution to the primary fermented mustard at a volume ratio of (1-1.5):1, and adjust the solution to the optimal pH value determined in step S2; then, inoculate the strain with high sensory evaluation onto the primary fermented mustard obtained in step S1 at a mass ratio of 2% to 3%, seal it, and perform secondary fermentation at room temperature to obtain mustard.

[0011] As a further solution of the present invention: in the step S1, the mass ratio of salt to mustard is 12% to 14%; the salt content of mustard after rinsing, desalting and squeezing and dehydrating is controlled at 7% to 8%, and the water content is controlled at 70% to 75%.

[0012] As a further scheme of the present invention: in the S2 step, the components of the MRS liquid culture medium are as follows in parts by mass: 8 to 12 parts of beef extract, 8 to 12 parts of peptone, 4 to 6 parts of yeast extract, 18 to 24 parts of glucose, 4 to 6 parts of sodium acetate, 1 to 2 parts of diammonium hydrogen citrate, 1 to 2 parts of dipotassium hydrogen phosphate, 0.2 to 0.3 parts of magnesium sulfate, 0.04 to 0.06 parts of manganese sulfate, 1 to 2 parts of anhydrous sorbitan monooleate polyoxyethylene ether and 800 to 1000 parts of distilled water; the pH of the MRS liquid culture medium is controlled between 6.2 and 6.6, and is sterilized at 121° C. under high pressure for 20 to 25 minutes.

[0013] As a further solution of the present invention: in the step S2, the MRS solid culture medium is prepared by adding 18 to 24 parts of agar to the MRS liquid culture medium.

[0014] As a further solution of the present invention: in the step S2, the MRS-CaCO3 medium is prepared by adding 18 to 24 parts of calcium carbonate to the MRS solid medium.

[0015] As a further solution of the present invention: in the S3 step, when the purified strain is cultured in the MRS liquid culture medium, the pH value of the fermentation broth is measured by sampling every 4 hours, and the pH value of the fermentation broth when a strain with vigorous growth and strong acid production ability appears is determined to obtain the optimal pH value of the fermentation broth.

[0016] As a further solution of the present invention: in the step S4, during the secondary fermentation, the total acid content and pH value are measured every day, and the fermentation is stopped when the pH value is between 3.2 and 3.8 and the total acid content is between 8 and 12 mg / g.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The invention provides the method of obtaining primary fermented mustard by laying mustard and salt separately and fermenting them; then extracting purified lactic acid bacteria strains from pickled mustard juice produced during the primary fermentation of mustard; then selecting strains with vigorous growth and strong acid production ability, conducting secondary fermentation test on the primary fermented mustard, and selecting strains used for mustard with high sensory evaluation; then inoculating the strains with high sensory evaluation into the primary fermented mustard, adding sugar solution, and conducting secondary fermentation to obtain mustard; the mustard prepared by the process has bright and golden color, good crispness, strong aroma, pure flavor, and sweet and sour taste. DETAILED DESCRIPTION

[0019] Example 1

[0020] In an embodiment of the present invention, a secondary fermentation process of mustard tuber comprises the following steps:

[0021] S1. Primary fermentation of mustard: fresh mustard is selected and spread in a fermentation tank in a manner of a layer of mustard and a layer of salt, wherein the mass ratio of salt to mustard is 12%; a plastic film is covered and sealed, and compacted; after pickling for 45 days, the mustard is rinsed and desalted, and squeezed and dehydrated, so that the salt content in the mustard is controlled at 7%, and the water content is controlled at 70%, to obtain primary fermented mustard for use;

[0022] S2, lactic acid bacteria extraction: take 8 parts of beef extract, 8 parts of peptone, 4 parts of yeast extract, 18 parts of glucose, 4 parts of sodium acetate, 1 part of diammonium hydrogen citrate, 1 part of dipotassium hydrogen phosphate, 0.2 parts of magnesium sulfate, 0.04 parts of manganese sulfate, 1 part of dehydrated sorbitan monooleate polyoxyethylene ether and 800 parts of distilled water according to mass parts, mix, adjust the pH value to 6.2, and sterilize under high pressure at 121°C for 20 min to obtain MRS liquid culture medium for standby use;

[0023] Add 18 parts of agar to the MRS liquid medium to obtain an MRS solid medium for later use;

[0024] Add 18 parts of calcium carbonate to the MRS solid medium to obtain MRS-CaCO3 medium for later use;

[0025] The sauerkraut juice produced during the first fermentation of mustard was inoculated into MRS liquid culture medium at a volume ratio of 1:10, mixed thoroughly and cultured at 37°C for 36 h. After centrifugation, the suspended bacteria were obtained. The suspended bacteria were diluted 100 times and then inoculated into CaCO at a volume ratio of 1:10. 3 -MRS medium, mix thoroughly and culture at 37°C for 36 hours, select the larger colonies and separate them by streaking on MRS solid medium until colonies with uniform morphology and size are cultured, thus obtaining the purified strain;

[0026] S3. Screening of lactic acid bacteria: After diluting the purified strain 100 times, inoculate it into MRS liquid culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 36 hours, select strains with vigorous growth and strong acid production ability, wherein the pH value of the fermentation liquid is measured every 4 hours, and the pH value of the fermentation liquid when the strain with vigorous growth and strong acid production ability appears is determined to obtain the optimal pH value of the fermentation liquid; then take mustard samples from the first fermentation mustard, inoculate the strains with vigorous growth and strong acid production ability into the mustard samples at a mass ratio of 2%, seal them, ferment them for 5 days, obtain mustard samples after secondary fermentation, and perform sensory evaluation on them, and select strains used for mustard with high sensory evaluation;

[0027] S4. Secondary fermentation of mustard: dissolve sucrose in water at a mass ratio of 1:100 to obtain a sugar solution, add the sugar solution to the primary fermented mustard at a volume ratio of 1:1, and adjust the solution to an optimal pH value; then, inoculate the primary fermented mustard with a strain with high sensory evaluation at a mass ratio of 2%, seal it, and carry out secondary fermentation at room temperature, measure the total acid content and pH value every day, and stop the fermentation when the pH value is 3.2 and the total acid content is 8 mg / g to obtain mustard.

[0028] Example 2

[0029] In an embodiment of the present invention, a secondary fermentation process of mustard tuber comprises the following steps:

[0030] S1. Primary fermentation of mustard: fresh mustard is selected and spread in a fermentation tank in a manner of a layer of mustard and a layer of salt, wherein the mass ratio of salt to mustard is 13%; a plastic film is covered and sealed, and compacted; after pickling for 52 days, the mustard is rinsed and desalted and squeezed to dehydrate, so that the salt content in the mustard is controlled at 7.5% and the water content is controlled at 72%, and primary fermented mustard is obtained for use;

[0031] S2, lactic acid bacteria extraction: take 10 parts of beef extract, 10 parts of peptone, 5 parts of yeast extract, 21 parts of glucose, 5 parts of sodium acetate, 1.5 parts of diammonium hydrogen citrate, 1.5 parts of dipotassium hydrogen phosphate, 0.25 parts of magnesium sulfate, 0.05 parts of manganese sulfate, 1.5 parts of sorbitan monooleate polyoxyethylene ether and 900 parts of distilled water according to mass parts, mix, adjust the pH value to between 6.4, and sterilize at 121 ° C. for 22 minutes to obtain MRS liquid culture medium for standby use;

[0032] Add 21 parts of agar to the MRS liquid medium to obtain an MRS solid medium for later use;

[0033] Add 21 parts of calcium carbonate to the MRS solid medium to obtain MRS-CaCO3 medium for later use;

[0034] The sauerkraut juice produced during the first fermentation of mustard was inoculated into MRS liquid culture medium at a volume ratio of 1:10, mixed thoroughly and cultured at 37°C for 40 h. After centrifugation, the suspended bacteria were obtained. The suspended bacteria were diluted 100 times and then inoculated into CaCO at a volume ratio of 1:10. 3 -MRS medium, mix thoroughly and culture at 37°C for 40h, select the larger colonies and separate them by streaking on MRS solid medium until colonies with uniform morphology and size are cultured, thus obtaining the purified strain;

[0035] S3, screening of lactic acid bacteria: after diluting the purified strain 100 times, inoculate it into MRS liquid culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 40 hours, select the strain with strong growth and acid production ability, wherein, sample and measure the pH value of the fermentation liquid every 4 hours, and determine the pH value of the fermentation liquid when the strain with strong growth and acid production ability appears, and obtain the optimal pH value of the fermentation liquid; then take mustard samples from the first fermentation mustard, inoculate the strain with strong growth and acid production ability into the mustard samples at a mass ratio of 2.5%, seal it, ferment it for 6 days, obtain the mustard samples after the second fermentation, and perform sensory evaluation on it, and select the strain used for mustard with high sensory evaluation;

[0036] S4. Secondary fermentation of mustard: sucrose is dissolved in water at a mass ratio of 2:100 to obtain a sugar solution, and the sugar solution is added to the primary fermented mustard at a volume ratio of 1.2:1, and the solution is adjusted to an optimal pH value; then, a strain with a high sensory evaluation is inoculated into the primary fermented mustard at a mass ratio of 2.5%, and after sealing, a secondary fermentation is carried out at room temperature. The total acid content and pH value are measured every day. When the pH value is 3.5 and the total acid content is 10 mg / g, the fermentation is stopped to obtain mustard.

[0037] Example 3

[0038] In an embodiment of the present invention, a secondary fermentation process of mustard tuber comprises the following steps:

[0039] S1. Primary fermentation of mustard: fresh mustard is selected and spread in a fermentation tank in a manner of a layer of mustard and a layer of salt, wherein the mass ratio of salt to mustard is 14%; a plastic film is covered and sealed, and compacted; after pickling for 60 days, the mustard is rinsed and desalted and squeezed to dehydrate, so that the salt content in the mustard is controlled at 8% and the water content is controlled at 75%, and primary fermented mustard is obtained for use;

[0040] S2, lactic acid bacteria extraction: according to mass parts, take 12 parts of beef extract, 12 parts of peptone, 6 parts of yeast extract, 24 parts of glucose, 6 parts of sodium acetate, 2 parts of diammonium hydrogen citrate, 2 parts of dipotassium hydrogen phosphate, 0.3 parts of magnesium sulfate, 0.06 parts of manganese sulfate, 2 parts of anhydrous sorbitan monooleate polyoxyethylene ether and 1000 parts of distilled water, mix, adjust the pH value to 6.6, and sterilize at 121 ° C. for 25 minutes to obtain MRS liquid culture medium for standby use;

[0041] Add 24 parts of agar to the MRS liquid medium to obtain an MRS solid medium for later use;

[0042] Add 24 parts of calcium carbonate to MRS solid medium to obtain MRS-CaCO3 medium for later use;

[0043] The sauerkraut juice produced during the first fermentation of mustard was inoculated into MRS liquid culture medium at a volume ratio of 1:10, mixed thoroughly and cultured at 37°C for 48 h. After centrifugation, the suspended bacteria were obtained. The suspended bacteria were diluted 100 times and then inoculated into CaCO at a volume ratio of 1:10. 3 -MRS medium, mix thoroughly and culture at 37°C for 48h, select the larger colonies and streak them on MRS solid medium until colonies with uniform morphology and size are cultured, thus obtaining the purified strain;

[0044] S3, screening of lactic acid bacteria: after diluting the purified strain 100 times, inoculate it into MRS liquid culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 48 hours, select the strain with strong growth and acid production ability, wherein, sample and measure the pH value of the fermentation liquid every 4 hours, and determine the pH value of the fermentation liquid when the strain with strong growth and acid production ability appears, and obtain the optimal pH value of the fermentation liquid; then take mustard samples from the first fermentation mustard, inoculate the strain with strong growth and acid production ability into the mustard samples at a mass ratio of 3%, seal it, ferment it for 7 days, obtain the mustard samples after the second fermentation, and conduct sensory evaluation on it, and select the strain used for mustard with high sensory evaluation;

[0045] S4. Secondary fermentation of mustard: sucrose is dissolved in water at a mass ratio of 3:100 to obtain a sugar solution, and the sugar solution is added to the primary fermented mustard at a volume ratio of 1.5:1, and the solution is adjusted to an optimal pH value; then, a strain with a high sensory evaluation is inoculated into the primary fermented mustard at a mass ratio of 3%, and after sealing, a secondary fermentation is carried out at room temperature. The total acid content and pH value are measured every day. When the pH value is 3.8 and the total acid content is 12 mg / g, the fermentation is stopped to obtain mustard.

[0046] In order to better illustrate the technical effect of the present invention, the following experiments are used to illustrate:

[0047] Example 1 of the secondary fermentation process of mustard tuber disclosed in the patent website (publication number CN102987306A) was used as comparative example 1, and Example 1 of the pickling process of fresh mustard tuber disclosed in the patent website (publication number CN104996944A) was used as comparative example 2.

[0048] The samples of mustard tuber prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were respectively selected and cleaned, and 10 professional assessors in the food industry were randomly selected to conduct sensory evaluation and scoring of the mustard tuber from four aspects: color, smell, taste, and texture; each item was scored 20 points, with a full score of 80 points; the assessors were required to be in good physical condition and not to eat irritating food within 24 hours; the scoring rules for color, smell, taste, and texture were as follows:

[0049] Color: Bright, golden color, 16-20 points; bright, grayish yellow color, 11-15 points; average, dark yellow color, 6-10 points; dark, dark brown color, 0-5 points;

[0050] Smell: Strong fragrance, 16-20 points; Strong fragrance, 11-15 points; Average fragrance, 6-10 points; Strange smell, 0-5 points;

[0051] Taste: If the pickled cabbage tastes pure, it will get 16 to 20 points; if the pickled cabbage tastes relatively pure, it will get 11 to 15 points; if the pickled cabbage tastes average, it will get 6 to 10 points; if the pickled cabbage tastes poor and has a foreign smell, it will get 0 to 5 points;

[0052] Texture: Good tenderness, 16-20 points; good tenderness, 11-15 points; average tenderness, 6-10 points; no tenderness, 0-5 points;

[0053] The average scores of color, smell, taste and texture, as well as the total score, are recorded in Table 1 below. Table 1 Sensory evaluation analysis table

[0054]

[0055] It can be seen from Table 1 above that the color and texture scores of the pickled mustard tubers prepared in Examples 1 to 3 and Comparative Examples 1 and 2 are significantly different; and the smell and taste scores of the pickled mustard tubers prepared in Examples 1 to 3 are significantly greater than those of Comparative Examples 1 and 2; thus, it can be concluded that the pickled mustard tubers prepared in Examples 1 to 3 and Comparative Examples 1 and 2 are bright and golden in color and have good crispness and tenderness; the pickled mustard tubers prepared in Examples 1 to 3 also have the characteristics of rich aroma and pure sauerkraut flavor; further, it can be concluded that the pickled mustard tubers prepared in the present invention are bright and golden in color, have good crispness and tenderness, have rich aroma, have pure flavor, and are sweet and sour.

[0056] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A secondary fermentation process for mustard tuber, characterized in that: The following steps are involved: S1. Primary fermentation of mustard: fresh mustard is selected, and a layer of mustard and a layer of salt are spread in a fermentation tank, which is sealed and compacted. After pickling for 45 to 60 days, the mustard is rinsed, desalted, squeezed and dehydrated to obtain primary fermented mustard for later use; S2. Lactic acid bacteria extraction: Take the sauerkraut juice produced during the first fermentation of mustard, inoculate it into MRS liquid culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 36-48h, and take the suspended bacteria after centrifugation; dilute the suspended bacteria 100 times, and then inoculate it into CaCO3-MRS culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 36-48h, select the larger colonies and separate them by streaking on MRS solid culture medium, until colonies with uniform colony morphology and size are cultured, thus obtaining the purified strain; S3. Screening of lactic acid bacteria: After diluting the purified strain 100 times, inoculate it into MRS liquid culture medium at a volume ratio of 1:10, mix it thoroughly and culture it at 37°C for 36-48h, select strains with strong growth and acid production ability, and measure the optimal pH value for strain growth; then take mustard samples from the first fermented mustard, inoculate the strains with strong growth and acid production ability into the mustard samples at a mass ratio of 2%-3%, seal them, ferment them for 5-7d, obtain mustard samples after the second fermentation, perform sensory evaluation on them, and select strains for mustard with high sensory evaluation; S4, secondary fermentation of mustard: dissolve sucrose in water at a mass ratio of (1-3):100 to obtain a sugar solution, add the sugar solution to the primary fermented mustard at a volume ratio of (1-1.5):1, and adjust the solution to the optimal pH value determined in step S2; then, inoculate the strain with high sensory evaluation onto the primary fermented mustard obtained in step S1 at a mass ratio of 2% to 3%, seal it, and perform secondary fermentation at room temperature to obtain mustard.

2. The secondary fermentation process of mustard tuber according to claim 1, characterized in that: In the step S1, the mass ratio of salt to mustard is 12% to 14%; the salt content of mustard after rinsing, desalting and squeezing and dehydrating is controlled at 7% to 8%, and the water content is controlled at 70% to 75%.

3. The secondary fermentation process of mustard tuber according to claim 1, characterized in that: In the S2 step, the components of the MRS liquid culture medium are as follows in parts by mass: 8 to 12 parts of beef extract, 8 to 12 parts of peptone, 4 to 6 parts of yeast extract, 18 to 24 parts of glucose, 4 to 6 parts of sodium acetate, 1 to 2 parts of diammonium hydrogen citrate, 1 to 2 parts of dipotassium hydrogen phosphate, 0.2 to 0.3 parts of magnesium sulfate, 0.04 to 0.06 parts of manganese sulfate, 1 to 2 parts of anhydrous sorbitan monooleate polyoxyethylene ether and 800 to 1000 parts of distilled water; the pH of the MRS liquid culture medium is controlled between 6.2 and 6.6, and is sterilized at 121° C. under high pressure for 20 to 25 minutes.

4. A secondary fermentation process of mustard tuber according to claim 3, characterized in that: In the step S2, the MRS solid culture medium is prepared by adding 18 to 24 parts of agar to the MRS liquid culture medium.

5. A secondary fermentation process of mustard tuber according to claim 4, characterized in that: In the step S2, the MRS-CaCO3 medium is prepared by adding 18 to 24 parts of calcium carbonate to the MRS solid medium.

6. The secondary fermentation process of mustard tuber according to claim 1, characterized in that: In the step S3, when the purified strain is cultured in the MRS liquid culture medium, the pH value of the fermentation broth is measured by sampling every 4 hours, and the pH value of the fermentation broth when the strain with vigorous growth and strong acid production ability appears is determined to obtain the optimal pH value of the fermentation broth.

7. The secondary fermentation process of mustard tuber according to claim 1, characterized in that: In the step S4, during the secondary fermentation, the total acid content and pH value are measured every day, and the fermentation is stopped when the pH value is between 3.2 and 3.8 and the total acid content is between 8 and 12 mg / g.

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