Celery seriflux fermented by compound bacteria and preparation method of celery seriflux

Abstract

The invention belongs to the technical field of fermented food, and relates to compound bacteria fermented celery slurry and a preparation method thereof. The invention provides a preparation method of compound bacteria fermented celery seriflux, which comprises the following steps: adding flour into boiling water, gelatinizing to obtain noodle soup, mixing the noodle soup with celery, and cooling to obtain a seed culture medium; and adding compound bacteria into the seed culture medium, and fermenting to obtain the celery slurry. According to the present invention, the compound bacteria composed of Lactobacillus paracasei and Hansenula anomala are adopted to perform fermentation to prepare the celery slurry, such that the problem of high nitrite content of the celery slurry is solved;

Description

Technical Field

[0001] The invention belongs to the technical field of fermented foods and relates to celery pulp water fermented by composite bacteria and a preparation method thereof. Background Art

[0002] Jiangshui is a fermented vegetable product, mainly made from seasonal vegetables or wild vegetables. It is usually started with noodle soup or the traditional "pickled vegetable starter" of farmers. The fermentation process includes acetic acid fermentation, alcohol fermentation and lactic acid fermentation, with lactic acid fermentation being the main one. During the fermentation of vegetables, lactic acid bacteria mainly use the soluble nutrients in vegetables for metabolism. They do not have the enzyme system to decompose cellulose and hydrolyze protein. The entire fermentation process neither destroys the existing protein and amino acids in vegetables nor destroys the cell tissue of vegetables. Jiangshui is a fermented vegetable. Nitrite will be produced during the fermentation process. A large amount of nitrite intake at one time can cause acute poisoning in the human body. At the same time, nitrite is also a precursor of nitrosamine, a carcinogen and teratogen. Jiangshui has a wide range of consumers, so its safety is very important. Summary of the invention

[0003] The purpose of the invention is to solve the technical problem of high nitrite content in pulp water.

[0004] Based on the above purpose, the present invention provides a composite bacteria fermented celery pulp water and a preparation method thereof to meet the needs in the art.

[0005] On the one hand, the present invention relates to a method for preparing celery slurry fermented by composite bacteria, which comprises: adding flour to boiling water for gelatinization to obtain noodle soup, mixing the noodle soup with celery, and cooling to obtain a seed culture medium;

[0006] Adding composite bacteria to the seed culture medium for fermentation to obtain celery pulp water;

[0007] The composite bacteria consists of Lactobacillus paracasei and Hansenula anomala.

[0008] Further, in the preparation method of celery slurry fermented by composite bacteria provided by the present invention, the ratio of Lactobacillus paracasei to Hansenula anomala is 2:1 to 1:5 in terms of bacterial colony count. The present invention verifies through experiments that when the ratio of Lactobacillus paracasei to Hansenula anomala is within this range, the color of the slurry is off-white, light yellow or light green, and the color state is good; when the ratio of Lactobacillus paracasei to Hansenula anomala is not within this range, the color of the slurry is yellow-green, gray-green, yellow, green, etc., and the color state is poor.

[0009] The present invention has been verified through experiments that, under a certain substrate concentration, as the strain ratio continues to increase, the pH value of the fermentation liquid slightly increases, the total acid continues to decrease, but the reducing sugar content has a tendency to remain basically stable after a slight decrease, and the strain ratio within this range is more conducive to the production of organic acids and flavor substances.

[0010] Furthermore, in the method for preparing celery slurry fermented by composite bacteria provided by the present invention, the absorbance of the inoculum of Lactobacillus paracasei and the inoculum of Hansenula anomala diluted 100 times is 0.50±0.02 in terms of OD600.

[0011] Preferably, in the method for preparing celery slurry fermented by composite bacteria provided by the present invention, the inoculation ratio of the Lactobacillus paracasei and Hansenula anomala inoculation solutions is 1:1, calculated by bacterial colony count.

[0012] Further, in the preparation method of celery slurry fermented by composite bacteria provided by the present invention, the concentration of flour in the noodle soup is 10-20g / L. The invention verified through experiments that with the increase of flour concentration, the pH value of the slurry gradually decreased, the acidity gradually increased, and the reducing sugar content first decreased and then gradually increased, indicating that although the increase of flour concentration increased the reducing sugar content, it was not further utilized by fermentation. The sensory evaluation results showed that when the flour concentration was less than 10g / L, the sour taste of the slurry was very light; when the flour concentration was 10g / L, the color of the slurry was pale and the sour taste was moderate; as the amount of flour increased, when it was greater than 30g / L, because there was more unused flour in the slurry, the color of the slurry was white and opaque, there were more flocculent precipitations and the sensory perception was poor, and the score gradually decreased. It can be seen that the sensory score of the slurry at a flour concentration of 10-20g / L is high, the cost is relatively low, and the proportion is appropriate.

[0013] Furthermore, in the method for preparing celery slurry fermented by composite bacteria provided by the present invention, the inoculation amount is 1% to 5% based on the volume ratio of the composite bacteria inoculation liquid to the seed culture medium.

[0014] Furthermore, in the method for preparing celery slurry fermented by composite bacteria provided by the present invention, the celery is cut into segments of 2 to 5 cm.

[0015] Furthermore, in the method for preparing celery pulp water fermented by composite bacteria provided by the present invention, the fermentation temperature is 30-40° C. and the fermentation time is 48-55 hours.

[0016] On the other hand, the present invention relates to a celery pulp water, which is prepared by the preparation method of the celery pulp water fermented by the composite bacteria.

[0017] On the other hand, the present invention relates to the use of a composite bacteria composed of Lactobacillus paracasei and Hansenulax abnormalis in preparing pulp water, wherein the ratio of the Lactobacillus paracasei and Hansenulax abnormalis is 2:1 to 1:5 in terms of bacterial colony count. The present invention verifies through experiments that, compared with commercially available pulp water or lactic acid bacteria fermented pulp water, when the composite bacteria composed of Lactobacillus paracasei and Hansenulax abnormalis are used to prepare pulp water, the nitrite content is not detected according to the second method in GB5009.33-2016 "Determination of Nitrite and Nitrate in Food", and the pulp water is more suitable for food production.

[0018] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects or advantages:

[0019] The invention verifies that when Lactobacillus paracasei and Hansenula anomala are used to ferment noodle soup containing vegetables, the content of nitrite in slurry can be effectively reduced. It is unexpectedly found that when Lactobacillus paracasei and Hansenula anomala perform composite fermentation on noodle soup containing vegetables, the content of nitrite in the obtained slurry is undetectable according to the determination result of the second method in GB5009.33-2016 "Determination of Nitrite and Nitrate in Foods". The optimal fermentation conditions are determined through further experiments, and good sensory evaluation is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a graph showing the results of a single-factor test of the inoculation ratio of composite bacteria.

[0022] Figure 2 This is the result of a single factor test on inoculum size.

[0023] Figure 3 This is the single factor test result graph of flour concentration.

[0024] Figure 4 This is the single factor test result chart of wheat and celery ratio.

[0025] Figure 5 This is a graph showing the test results of various parameters changing during the fermentation process.

[0026] Figure 6 This is a graph showing the test results of various parameters under different fermentation temperatures. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described below in conjunction with embodiments; however, the present invention is not limited to the following embodiments.

[0028] The experimental methods and detection methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0029] Example 1

[0030] This example provides a single factor experiment on preparing celery syrup by combined fermentation of composite bacteria.

[0031] Lactobacillus paracasei used in this example was purchased from Shanghai Beinuo Biotechnology Co., Ltd., with the item number CICC 20262. Hansenula anomala was purchased from Beinachuanglian Biotechnology Co., Ltd., with the item number BNCC 336003.

[0032] The pH value of the slurry is directly determined by a pH meter; the total acid content refers to GB 12456-2021 "National Food Safety Standard Determination of Total Acid in Food"; the reducing sugar content is based on GB5009.7-2016 "National Food Safety Standard Determination of Reducing Sugar in Food"; the lactic acid content is determined by high performance liquid chromatography; the volatile components are determined by gas chromatography-mass spectrometry; the nitrite content is determined by the second method in GB5009.33-2016 "Determination of Nitrite and Nitrate in Food"; the total flavonoids content is determined by the NaNO2-Al(NO3)3-NaOH method.

[0033] The sensory evaluation indexes refer to Table 1, and the number of evaluators is 10.

[0034] Table 1 Sensory evaluation index reference table

[0035]

[0036]

[0037] Preparation process: (1) Raw material pretreatment: Pick fresh celery (variety is wheat celery), clean it, wipe the surface moisture of the tender shoots with gauze, cut it into 2-5 cm segments, and take a total weight of 2 kg of the processed celery and put it directly into a 50 L fermentation container;

[0038] (2) Preparation of noodle soup: Measure 35 L of water, heat it to boiling, add 3500 g of flour, the flour is in a fine paste state without flour particles, and gelatinize for 30 min after slightly boiling to obtain noodle soup;

[0039] (3) inoculation fermentation: directly adding the noodle soup of step (2) into the fermentation container of step (1) and blanching for 2 hours, wherein the amount of noodle soup added is 25 times the mass of celery, cooling to 35° C. to prepare a fermentation medium, and then inoculating a fermentation bacterial solution, wherein the absorbance of the inoculation solution of Lactobacillus paracasei and the inoculation solution of Hansenula anomala diluted 100 times is 0.50±0.02 in terms of OD600; inoculating according to the ratio of bacterial concentration (OD600) of Lactobacillus paracasei: Hansenula anomala = 1:1, the inoculation amount of the mixed bacterial solution per liter of the fermentation medium is 1%, the fermentation temperature is 35° C., the fermentation time is 48 hours, and filtering with 400 mesh gauze after the fermentation is completed;

[0040] (4) Storage: Boil the slurry described in step (3) for 5 minutes for sterilization, cool and seal, and store in a refrigerator.

[0041] 1. Effect of the inoculation ratio of Lactobacillus paracasei and Hansenula anomala on the color of celery pulp water.

[0042] Referring to the above preparation process, the ratio of Lactobacillus paracasei: Hansenula anomala was set to 2:1, 1:1, 1:2, 1:3, 1:4, and 1:5, respectively. The test results are as follows: Figure 1 shown.

[0043] Depend on Figure 1 It can be known that under the determined substrate concentration, along with the continuous increase of the strain ratio, the pH value of the fermented liquid is slightly increased, and the total acid continuously decreases, but the reducing sugar content has a trend of substantially maintaining stability after a slight decrease. When the proportioning of Lactobacillus paracasei and abnormal Hansenula is 1:1, 1:2, 1:3, 1:4, 1:5, the celery slurry is off-white, light yellow or light green. When the present embodiment also tests the proportioning of Lactobacillus paracasei and abnormal Hansenula is 3:1, 2:1, 1:6, the color of the celery slurry is yellow-green, gray-green, yellow, green, etc., and the color and luster state is poor. Single factor test shows that the strain ratio is 1:1, which is more conducive to the generation of organic acids and flavor substances.

[0044] 2. Single factor test of inoculum size.

[0045] Referring to the above preparation process, different inoculation amounts were set. The test results are as follows: Figure 2 shown.

[0046] Depend on Figure 2 It can be seen that under a certain substrate concentration, as the inoculation amount continues to increase, the pH value of the fermentation broth decreases slightly, the total acid increases continuously, but the reducing sugar content has a tendency to remain stable after a slight decrease. According to sensory evaluation, when the inoculation amount is less than 1%, the larger the inoculation amount, the better the flavor of the slurry; when the inoculation amount is greater than 3%, the larger the inoculation amount, the lower the sensory score of the slurry. The main reason is that when the inoculation amount is too high, the slurry tastes too sour and the drinkability decreases. Therefore, the inoculation amount is preliminarily determined to be 1% to 5%.

[0047] 3. Single factor test of flour concentration

[0048] Referring to the above preparation process, the flour concentration (g / L) was set to 5, 10, 20, 30, and 40 respectively. The test results are as follows: Figure 3 shown.

[0049] Depend on Figure 3 It can be seen that in the experiment, with the increase of flour concentration, the pH value of the slurry gradually decreased, the acidity gradually increased, and the reducing sugar content first decreased and then gradually increased, indicating that although the increase in flour concentration increased the reducing sugar content, it was not further utilized by fermentation. The sensory evaluation results showed that when the flour concentration was less than 10g / L, the sour taste of the slurry was very light; when the flour concentration was 10g / L, the color of the slurry was pale and the sour taste was moderate; with the increase of flour dosage, when it was greater than 30g / L, because there was more unused flour in the slurry, the color of the slurry was white and opaque, there were more flocculent precipitations and the sensory perception was poor, and the score gradually decreased. It can be seen that the sensory score of the slurry when the flour concentration was 10-20g / L was higher, the cost was relatively low, and the proportion was appropriate.

[0050] Example 2

[0051] This embodiment provides a four-factor three-level orthogonal optimization experiment.

[0052] The preparation process is as shown in Example 1, and the experimental settings are shown in Table 2.

[0053] Table 2 Orthogonal optimization test settings

[0054]

[0055] Table 3 Orthogonal optimization test results

[0056]

[0057] Table 4 Results of physical and chemical and sensory indexes of orthogonal test samples

[0058]

[0059] Tables 3 and 4 are the results of the four-factor three-level orthogonal optimization test based on the single-factor test results. The physical and chemical index determination results, sensory evaluation and total score of the slurry samples of each test group are shown in Table 4. The experimental analysis shows that the influence of the four factors on the flavor of the slurry is B (flour ratio) > A (inoculation amount) > C (celery ratio) > D (fermentation time). The optimal process parameters are A2B3C3D3, that is, the slurry obtained when the inoculation amount is 400OD / L, flour is 16g / L, celery is 55g / L, and fermentation is 35℃ for 55h has a higher comprehensive evaluation and better overall quality. In addition, the present invention finds through experiments that when preparing pulp water using a composite bacteria composed of Lactobacillus paracasei and Hansenula anomala, the second method in GB5009.33-2016 "Determination of Nitrite and Nitrate in Food" is used to measure the nitrite content and show that no detection is found, indicating that the combined use of Lactobacillus paracasei and Hansenula anomala is beneficial to solving the problem of nitrite in pulp water. Finally, Lactobacillus paracasei or Hansenula anomala are fermented separately to prepare pulp water, although the nitrite content can be reduced relative to the conventional pulp water preparation method, its sensory evaluation is not ideal, resulting in difficulty in direct sale, and there is still a certain nitrite content.

[0060] As described above, the basic principle, main features and advantages of the present invention are well described. The above embodiments and descriptions are only descriptions of the preferred embodiments of the present invention, and the present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, various changes and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the protection scope determined by the present invention.

Claims

1. A method for preparing celery slurry fermented by composite bacteria, characterized in that: include: Adding flour to boiling water to gelatinize to obtain noodle soup, mixing the noodle soup with celery, and cooling to obtain a seed culture medium; Adding composite bacteria to the seed culture medium for fermentation to obtain celery pulp water; The composite bacteria consists of Lactobacillus paracasei and Hansenula anomala.

2. The method for preparing celery slurry fermented by composite bacteria according to claim 1, characterized in that: Calculated by bacterial colony count, the ratio of Lactobacillus paracasei to Hansenula anomala is 2:1 to 1:

5.

3. The method for preparing celery pulp water fermented by composite bacteria according to claim 1, characterized in that: In terms of OD600, the absorbance of the inoculum of Lactobacillus paracasei and the inoculum of Hansenula anomala diluted 100 times is 0.50±0.

02.

4. The method for preparing celery slurry fermented by composite bacteria according to claim 3, characterized in that: The inoculation ratio of the Lactobacillus paracasei and Hansenula anomala inoculation solutions is 1:1, based on the number of bacterial colonies.

5. The method for preparing celery slurry fermented by composite bacteria according to claim 1, characterized in that: The concentration of flour in the noodle soup is 10-20 g / L.

6. The method for preparing celery pulp water fermented by composite bacteria according to claim 1, characterized in that: Calculated by the volume ratio of the composite bacteria inoculation solution to the seed culture medium, the inoculation amount is 1% to 5%.

7. The method for preparing celery pulp water fermented by composite bacteria according to claim 1, characterized in that: The celery is cut into segments of 2 to 5 cm.

8. The method for preparing celery pulp water fermented by composite bacteria according to claim 1, characterized in that: The fermentation temperature is 30-40°C and the fermentation time is 48-55h.

9. A celery pulp water, characterized in that: The celery pulp water is prepared by the method for preparing celery pulp water fermented by composite bacteria according to any one of claims 1 to 8.

10. Use of a composite bacteria consisting of Lactobacillus paracasei and Hansenula anomala in preparing slurry, characterized in that: Calculated by bacterial colony count, the ratio of Lactobacillus paracasei to Hansenula anomala is 2:1 to 1:5.

Images