Lactic acid bacterium agent for selenium-rich fermentation of rape bee pollen as well as preparation method and application of lactic acid bacterium agent
By fermenting rapeseed bee pollen with a mixed inoculum of selenium-enriched lactic acid bacteria, the problems of insufficient release of nutrients and poor taste of bee pollen have been solved. This has achieved efficient selenium-enriched fermentation of bee pollen, improved the nutritional and functional activity of the product, and expanded its market applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHWEST UNIV
- Filing Date
- 2026-02-25
- Publication Date
- 2026-05-26
AI Technical Summary
Existing bee pollen fermentation methods suffer from low nutrient utilization, poor taste, and insufficient functional activity. In particular, the release of nutrients from bee pollen is insufficient under liquid fermentation conditions, and there is a lack of selenium-enriched probiotic products on the market.
A mixed inoculum of Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus rhamnosus was used to ferment rapeseed bee pollen. By adding sodium selenite during the fermentation process to convert inorganic selenium into organic selenium, a selenium-enriched lactic acid bacteria inoculum was prepared. Fermentation conditions such as temperature, time, and water volume were optimized to increase the organic selenium content.
It improves the utilization rate and functional activity of bee pollen nutrients, enhances the antioxidant capacity and immune function of bee pollen, and increases the added value and market appeal of the product.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of fermentation engineering technology, and in particular to a lactic acid bacteria agent for selenium-enriched fermentation of rapeseed bee pollen, its preparation method, and its application. Background Technology
[0002] Currently, there are two ways to ferment bee pollen: solid-state fermentation and liquid fermentation. Solid-state fermentation is more common in nature, but under solid-state conditions, biological fermentation can only occur on the surface of bee pollen grains and cannot react with the contents of the pollen wall. Under liquid fermentation conditions, the pollen will be suspended in the solution, which allows for more thorough contact with microorganisms and better fermentation. In addition, microbial proliferation is relatively faster under liquid conditions, and the fermentation cycle is shorter. Studies have shown that bee pollen products fermented under liquid conditions are richer in nutrients and contain more live bacteria. The effects and advantages of bee pollen fermented by probiotics: (1) Improved taste: During the formation of bee pollen, some fine sand, broken plant tissues, etc. will be wrapped inside the pollen grains, which are not easy to remove during processing. At the same time, some bee pollen has a distinct fishy smell, which will have a sandy taste and unpleasant flavor when consumers chew it directly. Before fermentation, bee pollen should be washed with sterile water to remove some of the sand. Microbial fermentation can increase the content of flavor substances such as tyrosine, phenylalanine and aromatic hydrocarbons, thus improving the taste. Liu Daiyao et al. used pomelo and bee pollen as the main raw materials and fermented them with lactic acid bacteria to make fermented bee pollen sauce with a unique bee pollen aroma and improved the original taste of bee pollen, making it more flavorful. (2) Improve nutritional value: The main component of the outer wall of bee pollen is sporogenin, which is strong and elastic and is a natural protective barrier, thus hindering the release of nutrients inside bee pollen, resulting in a nutrient digestibility and utilization rate of only 10% to 15%. However, the enzymes produced by microbial fermentation can destroy the outer wall of bee pollen, thereby improving the absorption and utilization rate of nutrients. Li Yongcheng used oyster mushrooms, shiitake mushrooms, Aspergillus oryzae and yeast to ferment and break the cell wall of mixed pollen, and found that the cell wall breaking rate of oyster mushrooms was 90.9%, that of shiitake mushrooms was 58.8%, that of Aspergillus oryzae was 89.3%, and that of yeast was 61.5%. (3) Enhance functional activity: Through the metabolism of microorganisms, not only can the content of the original nutrients in pollen be increased, but nutrients that the pollen itself does not have can also be produced. Some microorganisms can also secrete active substances such as polysaccharides and flavonoids. These active substances typically possess anti-aging, antioxidant, and immune-enhancing functions. Organically combining bee pollen with microorganisms can both preserve the nutritional value of the bee pollen and add the special effects of beneficial microorganisms to the product. Kaškoniene et al. fermented bee pollen using *Lactobacillus rhamnosus* and found that the total flavonoid content in the fermented bee pollen was 2.6–3.4 times higher than before fermentation, and the total phenolic content also increased by 1.1–1.4 times. Studies have found that pollen fermentation increases the content of essential amino acids and generates a new fermentation product, vitamin K, making nutrients easier for the human body to absorb and utilize.Duan Qianqian et al. used rapeseed bee pollen as raw material, selected Lactobacillus plantarum and Lactobacillus rhamnosus for mixed fermentation, and optimized the fermentation process. Compared with before and after fermentation, the total phenol and total flavonoid content of bee pollen increased by 16.09% and 51.02% respectively, the reducing sugar content and protein content decreased significantly, the total antioxidant capacity increased by 1.26 times, and the DPPH free radical scavenging rate and Fe were also improved. 2+ The chelation rates increased by 10.49% and 23.19%, respectively; the hyaluronidase activity inhibition rate reached 46.08%, and the ability to inhibit protein denaturation increased by 24.65%. The increase in polyphenolic flavonoids indicates that probiotic fermentation disrupted the cell walls of bee pollen, releasing nutritionally active substances.
[0003] Selenium is an essential trace element for the human body, possessing various biological activities such as antioxidant, immunomodulatory, cardiovascular protection, and anti-cancer effects. Diet is considered the primary source of selenium. However, selenium in nature mainly exists in the form of inorganic selenium, which is highly toxic. In contrast, organic selenium has a higher absorption and utilization rate, is easily absorbed by the body, and has relatively lower toxicity. Selenium-enriched probiotics convert inorganic selenium into organic selenium, which not only increases selenium intake and utilization but also avoids toxic reactions. Organic selenium mainly consists of selenocysteine and selenomethionine, which can be further synthesized into selenoproteins, enhancing the activity of enzymes such as superoxide dismutase (SOD) and glutathione peroxidase. Therefore, various selenium-enriched foods are widely developed to meet the body's nutritional needs for selenium. Rapeseed bee pollen was listed as a new resource food as early as 2004, but it has not yet been utilized for high-value purposes.
[0004] Currently, selenium-enriched probiotics remain in the laboratory stage, and few selenium-enriched probiotic products are available on the market. Although the functional activity of fermented pollen products has been improved at present, their taste needs further improvement. Summary of the Invention
[0005] The purpose of this invention is to provide a lactic acid bacteria agent for selenium-enriched fermentation of rapeseed bee pollen, its preparation method, and its application, in order to solve the problems existing in the prior art. By using the lactic acid bacteria agent provided by this invention for the fermentation of rapeseed bee pollen, selenium-enriched fermented rapeseed bee pollen with new health benefits can be prepared.
[0006] To achieve the above objectives, the present invention provides the following solution:
[0007] This invention provides a lactic acid bacteria agent for selenium-enriched fermentation of rapeseed bee pollen, wherein the lactic acid bacteria include one or a mixture of several of the following: selenium-enriched Lactobacillus acidophilus, selenium-enriched Lactobacillus plantarum, and selenium-enriched Lactobacillus rhamnosus.
[0008] Preferably, the *Lactobacillus plantarum* is *Lactobacillus plantarum* JYLP-326; the *Lactobacillus acidophilus* is *Lactobacillus acidophilus* JYLA-191; and the *Lactobacillus rhamnosus* is *Lactobacillus rhamnosus* CRL1505.
[0009] Preferably, the lactic acid bacteria are a mixture of Lactobacillus plantarum cultured in selenium enrichment and Lactobacillus acidophilus cultured in selenium enrichment at a mass ratio of 1:2.
[0010] The present invention also provides a method for preparing the lactic acid bacteria inoculant, including the step of adding sodium selenite 2-12 hours after inoculating a lactic acid bacteria to ferment and obtain selenium-enriched lactic acid bacteria, which is the lactic acid bacteria inoculant.
[0011] Alternatively, the process may include inoculating lactic acid bacteria separately, adding sodium selenite 2-12 hours after inoculation for fermentation to obtain selenium-enriched lactic acid bacteria, and mixing the selenium-enriched lactic acid bacteria to obtain the lactic acid bacteria inoculum; wherein the amount of sodium selenite added is 2-10 mg / L.
[0012] Preferably, the process includes the steps of adding sodium selenite for fermentation 2-12 hours after inoculation with Lactobacillus plantarum or Lactobacillus acidophilus to obtain selenium-enriched Lactobacillus plantarum or selenium-enriched Lactobacillus acidophilus, and mixing the selenium-enriched Lactobacillus plantarum and the selenium-enriched Lactobacillus acidophilus to obtain the lactic acid bacteria inoculum.
[0013] Preferably, the sodium selenite is added at the 8th hour after inoculation.
[0014] The present invention also provides a fermentation method for selenium-enriched fermented rapeseed bee pollen, including the step of fermenting rapeseed bee pollen using the aforementioned lactic acid bacteria agent.
[0015] Preferably, the fermentation process conditions are: 3% lactic acid bacteria inoculation, 35°C fermentation temperature, 60h fermentation time, and 100% water addition.
[0016] The present invention also provides selenium-enriched fermented rapeseed bee pollen obtained by the fermentation method described above, wherein the total selenium content of the selenium-enriched fermented rapeseed bee pollen is 9.84 mg / kg and the organic selenium content is 8.41 mg / kg.
[0017] The present invention discloses the following technical effects:
[0018] This invention involves cultivating probiotics in selenium-enriched form to improve the efficiency of converting inorganic selenium into organic selenium, and then processing the resulting freeze-dried powder for use in actual production.
[0019] This invention endows fermented pollen with new health benefits—selenium-enriched fermented bee pollen. It stimulates consumer purchasing desire, significantly increases the added value of pollen products, and further expands the pollen product market. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 The effect of the ratio of bacterial strains on the number of viable bacteria in fermented rapeseed bee pollen;
[0022] Figure 2 The effect of water addition on the number of viable bacteria in fermented rapeseed bee pollen;
[0023] Figure 3 The effect of time on the number of viable bacteria in fermented rapeseed bee pollen;
[0024] Figure 4 The effect of temperature on the number of viable bacteria in fermented rapeseed bee pollen;
[0025] Figure 5 The effect of inoculum size on the number of viable bacteria in fermented rapeseed bee pollen. Detailed Implementation
[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0029] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0030] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0031] Example 1
[0032] To obtain selenium-enriched probiotics suitable for industrial production, a selenium-tolerant method and shake-flask fermentation were used to screen lactic acid bacteria strains with strong selenium enrichment capacity and high biomass from *Lactobacillus acidophilus*, *Lactobacillus plantarum*, and *Lactobacillus rhamnosus*. Orthogonal experiments were conducted to optimize the strains, selenium addition time, and selenium concentration, using selenium conversion rate and the number of viable bacteria after 24 hours of selenium enrichment as indicators.
[0033] I. Experimental Methods
[0034] 1. Activation of lactic acid bacteria
[0035] The freeze-dried bacterial powders (including Lactobacillus plantarum JYLP-326, Lactobacillus acidophilus JYLA-191, and Lactobacillus rhamnosus CRL1505, all of which are commercial strains purchased from Minsheng Zhongke Jiayi (Shandong) Biotechnology Co., Ltd.) were aseptically inoculated into MRS liquid medium and cultured at 37°C for 12-24 hours. After activating for 2-3 generations, they were ready for strain screening.
[0036] 2. Screening of selenium-enriched lactic acid bacteria
[0037] The activated bacterial culture was inoculated into MRS liquid medium containing sodium selenite at a ratio of 1% and cultured at 37°C until the logarithmic growth phase (10-12 h). 10 mL of the bacterial culture that had reached the logarithmic growth phase was taken and centrifuged at 12000 r / min for 10 min. The total selenium content in the culture medium and the bacterial supernatant was determined by the first method, hydride atomic fluorescence spectrometry, in the National Food Safety Standard GB5009.93-2017, "Determination of Selenium in Food".
[0038] The inorganic selenium content in the culture medium was determined according to the method of Zhang Ying et al. (Zhang Ying, Yang Qingqing, Song Yi, et al. Determination of inorganic and organic selenium content in selenium-enriched foods by high performance liquid chromatography-inductively coupled plasma mass spectrometry [J]. Chinese Journal of Food Hygiene, 2017(2).DOI:10.13590 / j.cjfh.2017.02.014.). 5 mL of culture medium supernatant and 20 mL of ultrapure water were accurately transferred to a 50 mL centrifuge tube and extracted by shaking in a 70℃ water bath for 1 h. After cooling, the mixture was ultrasonically extracted for 20 min, centrifuged at 4℃ and 8500 rpm for 10 min, and the supernatant was transferred. The solid-phase extraction column was activated with 10 mL of 3 mol / L hydrochloric acid solution and 20 mL of ultrapure water, 5 mL of sample was loaded, 10 mL of ultrapure water was added for rinsing, and then eluted with 10 mL of 3 mol / L hydrochloric acid solution. The eluent was collected. The inorganic selenium content in the eluent was determined using the total selenium method, with a blank test performed simultaneously. The organic selenium content was obtained by the difference method, i.e., the difference between the total selenium content and the inorganic selenium content. The selenium conversion rate of each strain was calculated based on the test results.
[0039] 3. Orthogonal design experiment for the preparation process of selenium-enriched lactic acid bacteria
[0040] The orthogonal design experiment for the preparation process of selenium-enriched lactic acid bacteria, and the orthogonal factor levels of the preparation conditions are shown in Table 1.
[0041] Table 1. Orthogonal factor levels for preparation conditions
[0042]
[0043] 4. Determination of weighting coefficients
[0044] Based on experience and the magnitude of their role in practical applications, the weighting coefficients for selenium conversion rate and viable bacteria count were determined to be 0.75 and 0.25, respectively, using the analytic hierarchy process (AHP) (i.e., overall score = selenium conversion rate × 75% + viable bacteria count × 25%).
[0045] 5. Orthogonal experiment
[0046] Single-factor experiments were conducted on the strains (Lactobacillus acidophilus JYLA-191, Lactobacillus plantarum JYLP-326, and Lactobacillus rhamnosus CRL1505), selenium addition time (2h, 4h, 6h, 8h, 10h), and selenium concentration (2mg / L, 4mg / L, 6mg / L, 8mg / L, 10mg / L). Based on the single-factor experiments, the preparation process was optimized using an Lg(35) orthogonal array. The combined index of selenium conversion rate and viable bacteria count was calculated using a multi-index weighted scoring method and statistically analyzed. The results are shown in Table 2.
[0047] Table 2. Intuitive Analysis of Orthogonal Experiment for the Preparation Process of Selenium-Enriched Lactic Acid Bacteria
[0048]
[0049]
[0050] As shown in Table 2, Lactobacillus acidophilus JYLA-191 and Lactobacillus plantarum JYLP-326, when selenium was added at 8h with a sodium selenite addition of 2 mg / L, exhibited high selenium conversion rate, high viable bacterial count, and high overall score.
[0051] Therefore, this invention selects Lactobacillus acidophilus JYLA-191 and Lactobacillus plantarum JYLP-326 as the main components of the selenium-enriched bacterial agent. Next, the process of these two selenium-enriched lactic acid bacteria in rapeseed bee pollen fermentation was studied.
[0052] The general method for fermenting rapeseed bee pollen using selenium-enriched lactic acid bacteria is as follows: Water is added to bee pollen that has been sterilized with edible alcohol, stirred evenly, then selenium-enriched lactic acid bacteria are added and mixed thoroughly. The mixture is then placed in a constant temperature incubator for cultivation. The parameters in this process are now optimized as follows:
[0053] (1) Selection of strains
[0054] Selenium-enriched *Lactobacillus plantarum* JYLP-326 and selenium-enriched *Lactobacillus acidophilus* were prepared according to the above-mentioned preferred conditions. Then, the culture medium was washed away, and 5% sodium alginate, 0.8% sodium bicarbonate, 12% xylooligosaccharides, and 3% sucrose were added. The mixture was then freeze-dried to obtain *Lactobacillus plantarum* JYLP-326 bacterial powder (bacterial concentration 2.3 × 10⁻⁶). 9 CFU / g) and selenium-enriched Lactobacillus acidophilus JYLA-191 bacterial powder (concentration of 1.5×10⁻⁶ CFU / g) 9 CFU / g).
[0055] The total inoculum was kept at 5% of the bee pollen mass, water was added at 100%, and fermentation time was 72 hours. The effects of selenium-enriched Lactobacillus plantarum powder and selenium-enriched Lactobacillus acidophilus powder mass ratios of 1:1, 1:2, 1:3, 1:4, and 1:5 on the viable bacteria count in rapeseed bee pollen were studied to evaluate the fermentation effect of rapeseed bee pollen.
[0056] (2) Selection of water volume
[0057] The bacterial strains were kept at a mass ratio of 1:2 of selenium-enriched Lactobacillus plantarum and selenium-enriched Lactobacillus acidophilus, with a total inoculum of 5% and a fermentation time of 72 h. The effects of adding water at concentrations of 80%, 90%, 100%, 110%, and 120% on the number of viable bacteria in rapeseed bee pollen were studied to evaluate the fermentation effect of rapeseed bee pollen.
[0058] (3) Selection of fermentation time
[0059] The bacterial strain was kept at a mass ratio of selenium-enriched Lactobacillus plantarum to selenium-enriched Lactobacillus acidophilus of 1:2, with a total inoculum of 5% and 100% water added. The effects of fermentation times of 24h, 36h, 48h, 60h and 72h on the number of viable bacteria in rapeseed bee pollen were studied to evaluate the fermentation effect of rapeseed bee pollen.
[0060] (4) Selection of fermentation temperature
[0061] The bacterial strain was maintained at a mass ratio of selenium-enriched Lactobacillus plantarum to selenium-enriched Lactobacillus acidophilus of 1:2, with a total inoculum of 5% and 100% water added. The effects of fermentation times of 31℃, 33℃, 35℃, 37℃ and 39℃ on the number of viable bacteria in rapeseed bee pollen were studied to evaluate the fermentation effect of rapeseed bee pollen.
[0062] (5) Selection of inoculum size
[0063] The bacterial strain was maintained at a mass ratio of selenium-enriched Lactobacillus plantarum to selenium-enriched Lactobacillus acidophilus of 1:2, with 100% water added. The fermentation time was 60 h and the fermentation temperature was 35℃. The effect of inoculum concentrations of 1%, 3%, 5%, 7%, and 9% on the number of viable bacteria in rapeseed bee pollen was studied to evaluate the fermentation effect of rapeseed bee pollen.
[0064] Experimental results show that ( Figures 1-5 The highest viable cell count was observed when the mass ratio of *Lactobacillus plantarum* to *Lactobacillus acidophilus* was 1:2. Therefore, when studying the amount of water added, fermentation time, fermentation temperature, and inoculum size, a compound strain with a mass ratio of *Lactobacillus plantarum* to *Lactobacillus acidophilus* of 1:2 was selected. The results showed that the highest viable cell count and best fermentation effect were achieved when the water content was 100%, the fermentation time was 60 h, the fermentation temperature was 35℃, and the inoculum size was 3%. At this point, the total selenium content was 9.84 mg / kg, and the organic selenium content was 8.41 mg / kg.
[0065] Example 2
[0066] Based on the results of the orthogonal experiment in Example 1, a compound strain of Lactobacillus plantarum and Lactobacillus acidophilus with a mass ratio of 1:2 was selected for the preparation of selenium-enriched lactic acid bacteria inoculum.
[0067] Bacterial strains: Lactobacillus acidophilus JYLA-191, Lactobacillus plantarum JYLP-326.
[0068] Preparation of selenium-enriched culture medium: Add 2 mg / L sodium selenite to MRS culture medium.
[0069] Seed culture: Lactobacillus acidophilus and Lactobacillus plantarum were inoculated into MRS medium and cultured at 37°C for 6 hours.
[0070] Selenium-enriched fermentation: The seed liquid was inoculated into the selenium-enriched culture medium at an inoculation rate of 3%, and sodium selenite was added at 8 h. Fermentation was carried out at 37℃ for 30 h.
[0071] Collection of selenium-enriched lactic acid bacteria: After fermentation, the culture medium was washed away, and 5% sodium alginate, 0.8% sodium bicarbonate, 12% xylooligosaccharides, and 3% sucrose were added. The mixture was then freeze-dried to obtain selenium-enriched *Lactobacillus plantarum* JYLP-326 bacterial powder (concentration 2.3 × 10⁻⁶). 9 CFU / g) and selenium-enriched Lactobacillus acidophilus JYLA-191 bacterial powder (concentration of 1.5×10⁻⁶ CFU / g) 9 The lactic acid bacteria agent was obtained by mixing selenium-enriched Lactobacillus plantarum JYLP-326 powder and selenium-enriched Lactobacillus acidophilus JYLA-191 powder at a mass ratio of 1:2, washing with physiological saline, and then freeze-drying.
[0072] Application Example 1
[0073] 40% sterile water was added to bee pollen sterilized with edible alcohol, and after stirring evenly, the lactic acid bacteria inoculum prepared in Example 2 (inoculation amount of 0.3% of pollen mass) was added, mixed evenly, and placed in a constant temperature incubator (35℃) for 48 hours. Changes in bioactive substances before and after fermentation were measured, with fermentation without added bacteria and fermentation using unenriched lactic acid bacteria inoculum serving as controls. The results are shown in Table 3. The results showed that the total antioxidant capacity of rapeseed bee pollen fermented with selenium-enriched lactic acid bacteria inoculum was 105% higher than that fermented with ordinary unenriched lactic acid bacteria inoculum, and 161% higher than that of unfermented bee pollen; the DPPH free radical scavenging ability of rapeseed bee pollen fermented with selenium-enriched lactic acid bacteria inoculum was enhanced by 88.4% compared to rapeseed bee pollen fermented with ordinary unenriched lactic acid bacteria inoculum, and enhanced by 187% compared to unfermented bee pollen. These results provide a theoretical basis for the market launch of selenium-enriched fermented bee pollen products.
[0074] Table 3. Changes in antioxidant activity of rapeseed bee pollen before and after fermentation
[0075]
[0076] Example 3
[0077] Strain screening: Lactobacillus plantarum was isolated from yogurt and designated as Lb. plantarum ST-III.
[0078] Culture medium preparation: Add 8 mg / L sodium selenite to MRS medium.
[0079] Seed culture: Lactobacillus plantarum was inoculated into MRS medium and cultured at 37°C for 6 hours.
[0080] Selenium-enriched fermentation: The seed liquid was inoculated into the selenium-enriched culture medium at an inoculation rate of 3%, and fermented at 37°C for 30 hours.
[0081] Collection of selenium-enriched lactic acid bacteria: After fermentation, the bacterial cells are collected by centrifugation, washed with physiological saline, and then freeze-dried to obtain selenium-enriched lactic acid bacteria powder.
[0082] Example 4
[0083] Strain screening: Lactobacillus delbrueckii subsp. bulgaricus was isolated from kimchi, with the identification number Lactobacillus delbrueckii subsp. bulgaricus CICC6045.
[0084] Culture medium preparation: Add 10 mg / mL sodium selenite to MRS medium.
[0085] Seed culture: Lactobacillus delbrueckii subsp. bulgaricus was inoculated into MRS medium and cultured at 37°C for 8 hours.
[0086] Selenium-enriched fermentation: Inoculate the seed liquid into the selenium-enriched culture medium at an inoculation rate of 5% and ferment at 37°C for 24 hours.
[0087] Collection of selenium-enriched lactic acid bacteria: After fermentation, the bacterial cells are collected by centrifugation, washed with physiological saline, and then freeze-dried to obtain selenium-enriched lactic acid bacteria powder.
[0088] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A lactic acid bacteria agent for selenium-enriched fermentation of rapeseed bee pollen, characterized in that, The lactic acid bacteria include one or a mixture of several of the following: Lactobacillus acidophilus cultured in selenium-enriched medium, Lactobacillus plantarum cultured in selenium-enriched medium, and Lactobacillus rhamnosus cultured in selenium-enriched medium.
2. The lactic acid bacteria agent as described in claim 1, characterized in that, The *Lactobacillus plantarum* is *Lactobacillus plantarum* JYLP-326; the *Lactobacillus acidophilus* is *Lactobacillus acidophilus* JYLA-191; and the *Lactobacillus rhamnosus* is *Lactobacillus rhamnosus* CRL1505.
3. The lactic acid bacteria agent as described in claim 1, characterized in that, The lactic acid bacteria are a mixture of Lactobacillus plantarum cultured in selenium and Lactobacillus acidophilus cultured in selenium at a mass ratio of 1:
2.
4. The method for preparing the lactic acid bacteria inoculant according to any one of claims 1-3, characterized in that, The process includes adding sodium selenite 2-12 hours after inoculation with a type of lactic acid bacteria to ferment and obtain selenium-enriched lactic acid bacteria, which is the lactic acid bacteria inoculum. Alternatively, the process may include inoculating lactic acid bacteria separately, adding sodium selenite 2-12 hours after inoculation for fermentation to obtain selenium-enriched lactic acid bacteria, and mixing the selenium-enriched lactic acid bacteria to obtain the lactic acid bacteria inoculum; wherein the amount of sodium selenite added is 2-10 mg / L.
5. The preparation method according to claim 4, characterized in that, The process includes the steps of adding sodium selenite for fermentation 2-12 hours after inoculation with Lactobacillus plantarum or Lactobacillus acidophilus to obtain selenium-enriched Lactobacillus plantarum or selenium-enriched Lactobacillus acidophilus, and mixing the selenium-enriched Lactobacillus plantarum and the selenium-enriched Lactobacillus acidophilus to obtain the lactic acid bacteria inoculum.
6. The preparation method according to claim 4, characterized in that, The sodium selenite was added at 8 hours after inoculation.
7. A fermentation method for selenium-enriched fermented rapeseed bee pollen, characterized in that, The method includes the step of fermenting rapeseed bee pollen using the lactic acid bacteria agent described in any one of claims 1-3.
8. The fermentation method as described in claim 7, characterized in that, The fermentation process conditions are as follows: 100% water added, 60 hours of fermentation, 35°C of fermentation temperature, and 3% of the rapeseed bee pollen inoculum amount of lactic acid bacteria.
9. A type of selenium-enriched fermented rapeseed bee pollen obtained by the fermentation method as described in claim 7 or 8, characterized in that, The total selenium content of the selenium-enriched fermented rapeseed bee pollen is 9.84 mg / kg, and the organic selenium content is 8.41 mg / kg.