A Lactobacillus plantarum LP.1 and its applications

Abstract

The present invention belongs to the field of microbial technology, and particularly relates to a Lactobacillus plantarum LP.1 and its application. The present invention provides a Lactobacillus plantarum LP.1 strain, which has excellent color protection effect and strong tolerance, and can effectively solve the problems of dull color and easy browning of fermented chili peppers. When used for pickling and fermenting millet peppers, it can keep the millet peppers golden in color without adding color protectants such as sodium metabisulfite, improve the color of millet peppers, reduce potential food safety risks, and can play an obvious color protection effect throughout the shelf life of millet pepper products, maintain the quality stability of the product shelf life, improve the product quality, and has industrial application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbiology, and particularly relates to a Lactobacillus plantarum LP.1 and its application. Background Art

[0002] The fermentation and processing of vegetables can endow products with unique flavors and is a traditional method for vegetable processing and preservation. Among fermented vegetables, there are relatively many fermented pepper products, which are deeply loved and welcomed by people. Fermented peppers can be used as seasonings or directly as dishes. For traditional natural fermentation of millet peppers, the quality of batch fermentation is unstable, the color is dull, it is prone to browning, and the potential food safety risk is high. Currently, food additive - sodium metabisulfite is commonly used as an antioxidant in pickled millet pepper products, which can significantly improve the color of naturally fermented millet peppers, but it has certain carcinogenicity and there are certain food safety risks.

[0003] In recent years, studies have found that some microorganisms can play a good color protection effect in the food processing process. For example, patent CN202110597239.1 discloses a method for color protection of meat surface microorganisms. Red meat is soaked in a composite bacterial solution fermented by a mixture of Oceanobacillus sp. and Staphylococcus sp. for 10 - 20 min to stabilize the color on the surface of the red meat and prevent browning of the meat blocks due to the oxidation of surface hemoglobin during later storage, thereby achieving the effect of biological color protection on the surface of red meat. Patent CN201110090814.5 discloses a Lactobacillus salivarius for protecting the color of meat products. The strain is made into a color protection agent for meat products, which has strong color protection ability, can not only maintain the original flavor of the product but also keep the fresh or fermented meat bright in color. Currently, there is no research report on biological source color protection of lactic acid bacteria in the field of pickled vegetables. Summary of the Invention

[0004] Based on the above technical problems, the main object of the present invention is to overcome the deficiencies of the above background art, and a strain of Lactobacillus plantarum LP.1 is screened and obtained. This strain has excellent color protection effect and strong tolerance performance, and can effectively solve the problems of dull color and easy browning of fermented peppers. When used for pickling and fermenting millet peppers, it can keep the millet peppers golden in color without adding color protection agents such as sodium metabisulfite, improve the color of millet peppers, reduce potential food safety risks, and has industrial application value.

[0005] To achieve the above object, the inventors conducted in - depth research and completed the present invention through repeated research and demonstration. The specific content is as follows:

[0006] In a first aspect, an embodiment of the present application provides a strain of Lactobacillus plantarum LP.1, which was deposited with the China General Microbiological Culture Collection Center on May 6, 2024, and the deposit number is CGMCC No. 30505.

[0007] The colonies of Lactobacillus plantarum LP.1 strain on MRS medium are milky white, with neat and round edges, smooth surface, moist and shiny; after Gram staining and observing under a microscope, the cells of this strain are in the typical rod-shaped bacteria morphology, with a cell length of 0.5 - 0.8 μm and a width of 0.2 - 0.4 μm.

[0008] In a second aspect, the present invention also provides a fermentation inoculant, which contains the above-mentioned Lactobacillus plantarum LP.1.

[0009] In a third aspect, the present invention also provides the application of the above-mentioned Lactobacillus plantarum or fermentation inoculant in the fermentation of chili peppers, especially for maintaining the color of chili peppers, preferably fermenting millet chili peppers.

[0010] LP.1 is a facultative anaerobe. Using chili peppers as the fermentation substrate, LP.1 colonizes inside and on the surface of various tissues of chili peppers. On the one hand, it can consume part of the oxygen, forming a relatively anaerobic fermentation environment and weakening the oxidative browning of chili peppers; on the other hand, when LP.1 ferments chili peppers, it can quickly produce organic acids, causing the pH of the chili pepper fermentation system to drop rapidly. The low-pH environment inactivates the activities of phenolase, ascorbic acid oxidase, and peroxidase, thereby weakening enzymatic browning. It is also possible that the LP.1 strain can utilize the chili pepper raw materials to metabolize and produce color-protecting substances, achieving a color-protecting effect.

[0011] In a fourth aspect, the present invention also provides a method for fermenting millet chili peppers, which is a method of adding the above-mentioned Lactobacillus plantarum or fermentation inoculant to millet chili peppers for fermentation.

[0012] Further, the inoculation time of the Lactobacillus plantarum or fermentation inoculant is at the initial stage of fermentation.

[0013] Further, the inoculation amount of the Lactobacillus plantarum is 10 4 -10 8 CFU / g

[0014] Further, the salt concentration added during the fermentation process is 0% - 10% (w / w).

[0015] Further, the fermentation time is 30 - 90 days.

[0016] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0017] 1. The Lactobacillus plantarum LP.1 provided by the present invention has a remarkable color protection effect, and has the advantages of salt tolerance and acidophilia, which can effectively solve the problems of dull color and easy browning of fermented chili peppers.

[0018] 2. The Lactobacillus plantarum LP.1 strain provided by the present invention is used for pickling and fermenting millet peppers. Without adding color protectants such as sodium metabisulfite, it can keep the millet peppers in golden color, improve the color of millet peppers, and reduce potential food safety risks. Its color protection effect is equivalent to that of adding 500 ppm sodium metabisulfite (calculated by the residual amount of SO2) in the millet pepper product system, far superior to the color protection effect of the addition amount of 100 ppm sodium metabisulfite (calculated by the residual amount of SO2) specified in the "National Food Safety Standard - Standard for the Use of Food Additives" (GB 2760).

[0019] 3. The Lactobacillus plantarum LP.1 provided by the present invention can play an obvious color protection effect during the entire shelf life of millet pepper products, maintain the quality stability of the product shelf life, and improve the product quality.

[0020] 4. The Lactobacillus plantarum LP.1 provided by the present invention is derived from naturally fermented millet peppers and has no safety risks.

[0021] 5. The technical solution provided by the present invention adopts the direct-inoculation pure culture fermentation technology, which is simple in operation and convenient for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the colony morphology diagram of Lactobacillus plantarum LP.1;

[0023] Figure 2 It is the cell morphology diagram of Lactobacillus plantarum LP.1 under the microscope;

[0024] Figure 3 It is the growth curve of Lactobacillus plantarum LP.1 at different salt concentrations;

[0025] Figure 4 It is the growth curve of Lactobacillus plantarum LP.1 at different acid concentrations;

[0026] Figure 5 It is the browning degree of the accelerated test of millet pepper products;

[0027] The Lactobacillus plantarum LP.1 provided by the present invention was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on May 6, 2024. The address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit number is CGMCC No. 30505. The strain was received and registered by the deposit center on May 6, 2024, and was detected as a viable strain by the deposit center on May 6, 2024. DETAILED DESCRIPTION OF THE INVENTION

[0028] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains.

[0030] Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional food-grade reagents, methods, and equipment in the art.

[0031] The terms used herein in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0032] The terms and related measurement methods involved in the present invention are explained as follows:

[0033] 1. Method for isolating and determining lactic acid bacteria: Refer to "GB 4789.35-2023 National Food Safety Standard Microbiological Examination of Foods - Examination of Lactic Acid Bacteria".

[0034] 2. Sensory analysis method: Refer to GB / T 10221-2021 / ISO 5492:2008 "Sensory Analysis - Vocabulary".

[0035] 3. Color difference detection: Take the test pepper sample, discard the pepper seeds, pedicels, and pulp, and only keep the pepper skin. Grind the pepper skin into a uniformly colored test sample. Accurately weigh 5 g (accurate to 0.01 g) of the test sample into a special black test box. Cover the test box and the color difference meter with a black light-shielding cloth to achieve the effect of light filtering. Click the test button to test and record L*, a*, and b*. Calculate △E according to the formula.

[0036] 4. Browning degree detection: Take the test pepper sample, discard the pepper seeds, pedicels, and pulp, and only keep the pepper skin. Grind the pepper skin into a uniformly colored test sample. Accurately weigh 5 g (accurate to 0.01 g) of the test sample, make up the volume to 100 g with water, place it on a shaker at 200 r / min for extraction for 60 min, then take it out and centrifuge at 4000 r / min for 20 min. Take the supernatant and filter it through a medium-speed filter paper, and then take the filtrate for OD 420 absorbance measurement, and the browning degree is expressed by the absorbance value.

[0037] Example 1 Screening of Lactobacillus plantarum LP.1

[0038] 1. Treatment of raw materials:

[0039] Under aseptic operation conditions, weigh 25 g of millet peppers with good natural fermentation flavor, put them into 225 mL of sterile water, homogenize with a homogenizer for 30 min, and perform coating culture by the 10-fold serial dilution method. Dilute 10-fold with sterile water to 10 -1 -10 -6 Take 10 -4 、10 -5 、10 -6 , the bacterial suspensions of 3 dilution gradients, inoculate them onto the MRS solid medium by the pour plate method, inoculate 1 mL / dish for each dilution, place them in a constant temperature incubator at 30 °C, and culture anaerobically in an inverted position for 48 h.

[0040] Select the culture dishes with 30 - 300 CFU / dish, mark the colony morphology and describe the morphological differences, and perform microscopic morphological examination and description on the colonies with different colony morphologies. Select typical lactic acid bacteria for purification. After purification 3 times, prepare glycerol cryopreservation tubes and store them in a medical refrigerator at -80 °C for standby. A total of 3 test microorganisms were obtained and named LP.1, 1402, and 6011.

[0041] 2. Screening of color-protecting strains for millet pepper fermentation

[0042] Take 200 μL of the frozen bacterial liquid of each of the 3 test strains screened above and inoculate them into 100 mL of liquid medium (MRS medium) respectively, culture statically at 37 °C for 48 h, and adjust the bacterial liquid concentration to 1×10 8 CFU / mL to obtain the test bacterial suspension.

[0043] Take fresh millet peppers, wash them with clean water, neatly put them into a 2.5 kg jar, compact them with a pressing net, add 3% (w / w) edible salt to the total system, mix the test bacterial suspension evenly with water, inoculate at a rate of 1×10 6 CFU / g, add water to the mouth of the jar, seal the jar, make marks, place it in a dark place for fermentation, and do daily maintenance. Take samples for browning degree every 15 d. Use 500 ppm sodium metabisulfite (calculated based on the residual amount of SO2) as a food additive as the positive control. The negative control group is the same as the experimental group except that the test strain and sodium metabisulfite are not added. Screen the microorganisms with good color-protecting effects based on the browning degree of fermented millet peppers, and record the results in Table 1.

[0044] Table 1 Browning degree test of fermented millet peppers with different strains

[0045]

[0046] Analysis of the data in Table 1 shows that the browning degree of the positive control group with sodium metabisulfite added at the initial stage of fermented chili peppers was the lowest at 0.109 Abs. As the fermentation time extended, browning gradually occurred in the peppers. Analyzing the results at 60 days of fermentation, the browning degrees were ranked from largest to smallest as CK > 6011 > 1402 > sodium metabisulfite ≈ LP.1. The browning degree of 500 ppm sodium metabisulfite was the lowest at 0.276 Abs, and the browning degree of LP.1 was 0.278 Abs. The color protection effect of LP.1 was equivalent to that of 500 ppm sodium metabisulfite. The browning degree of CK was the largest at 0.412 Abs. Thus, strain LP.1 was preferably selected as the microorganism with the best color protection effect for chili peppers.

[0047] 3. Strain Identification and Preservation

[0048] The colony morphology of the tested LP.1 strain in pure culture on MRS medium was as Figure 1 shown. The colonies were milky white, with neat and round edges, smooth surfaces, moist and shiny; the cell morphology observed under a microscope after Gram staining was as Figure 2 shown. The cells of this strain were in the typical rod-shaped bacterium morphology, with a cell length of 0.5 - 0.8 μm and a width of 0.2 - 0.4 μm. This result was obtained at a magnification of 1000 times. It was identified as Lactobacillus plantarum by sequencing and was preserved in the China General Microbiological Culture Collection Center on May 6, 2023, with the preservation number CGMCC No. 30505.

[0049] Example 2 Performance Test of Lactobacillus plantarum LP.1

[0050] 1. Salt Tolerance Performance Test of Lactobacillus plantarum LP.1

[0051] The culture medium for testing salt tolerance: Select MSR as the basal medium without adding NaCl, and the natural pH value is the CK medium, with the salt content not exceeding 0.5% (calculated by the mass fraction of NaCl). Taking the preparation of 3% NaCl medium as an example: Take a 300 mL Erlenmeyer flask, accurately weigh 97 g of liquid medium (accuracy ±0.01 g), accurately weigh 3 g of NaCl (accuracy ±0.0001 g), add NaCl to the liquid medium and dissolve it, then make a mark and seal it. Package it and sterilize it at 121 °C for 15 min. After cooling, it is the liquid medium with a 3% NaCl concentration. Prepare MRS liquid test media with NaCl mass fraction concentrations of 6%, 8%, 10%, and 12% in the same way.

[0052] Under aseptic operation, take the freshly prepared activity of 1×10 7 CFU / mL - 5×10 7CFU / mL suspension of Lactobacillus plantarum LP.1 was inoculated into test media with different salt concentrations at an inoculation amount of 1%, and each test treatment had 2 replicates. During the constant temperature culture at 30°C ± 1°C, samples were taken aseptically every 4 h, and the corresponding fresh sterile MRS liquid medium with Nacl was used as the blank control for zero adjustment to measure OD 600 . With time as the abscissa and OD 600 absorbance value as the ordinate, a growth curve was plotted, and the results are as Figure 4 shown.

[0053] Analysis Figure 3 of the results showed that in the 12% salt hypertonic medium, the reproduction of strain LP.1 was completely inhibited and the strain did not grow. In the 10% hypertonic medium, the adjustment period of strain LP.1 was very long, about 24 h, and it entered the logarithmic phase from 24 h to 32 h, showing signs of growth and reproduction of the strain, and it could reproduce in the 10% salt hypertonic solution. In the 8% hypertonic medium, the adjustment period of strain LP.1 was 8 h, it entered the logarithmic phase from 8 h to 28 h, was in the stationary phase from 28 h to 48 h, and entered the stationary phase and the decline phase after 48 h, and its growth activity was significantly higher than that in the 10% salt medium. In the 6% hypertonic medium, the adjustment period was 4 h, the logarithmic phase was from 4 h to 36 h, it entered the stationary phase from 36 h to 48 h, and began to enter the decline phase after 48 h. The growth trends of the 3% salt and CK were similar. The first 4 h was the growth adjustment period, 4 - 32 h was the growth logarithmic phase, 32 - 48 h was the growth stationary phase, and it entered the decline phase after 48 h. It can be seen that Lactobacillus plantarum LP.1 can grow and reproduce in the hypertonic medium, has salt tolerance, and still has biological activity at a salt concentration of 10%.

[0054] 2. Acid tolerance test of Lactobacillus plantarum LP.1

[0055] Test media for acid tolerance: Prepare MRS liquid medium without adding citric acid as the CK medium. Taking the medium with 0.5% acid as an example: Take a 300 mL Erlenmeyer flask, accurately weigh 100 g of the liquid medium (accuracy 0.01 g), slowly add food-grade citric acid to dissolve it, let it stand for 30 mins, then measure the acid content until the acid content value reaches 0.5%, make a mark and seal it, package it and sterilize it at 121°C for 15 mins, and use it after cooling. Prepare MRS liquid test media with acid contents of 0.75%, 1%, 1.25%, and 1.5% in the same way.

[0056] Under aseptic operation, take the freshly prepared one with an activity of 1×10 7 CFU / mL to 5×10 7CFU / mL of the test bacterial suspension was inoculated into the test medium with different acid concentrations, and the inoculation amount was 1%. There were 2 replicates for each test treatment. During the constant temperature culture at 30°C ± 1°C, samples were taken aseptically every 4 h. Each test group was zeroed with the corresponding pH-value fresh sterile MRS liquid medium as the blank control, and OD was measured. 600 . With time as the abscissa and OD 600 absorbance value as the ordinate, a growth curve was plotted. The results are as Figure 5 shown.

[0057] Analysis Figure 4 of the results showed that strain LP.1 could grow and reproduce in the 1.5% high-acid medium. The adjustment period was 8 h, the logarithmic phase was from 8 h to 28 h, it entered the stationary phase after 28 h to 32 h, and entered the decline phase after 32 h. Its growth was significantly inhibited compared with CK. It could grow normally in the 1.25% high-acid medium. The adjustment period was 4 h, the logarithmic phase was from 4 h to 24 h, it entered the stationary phase after 24 h to 32 h, and entered the decline phase after 32 h. Its growth was inhibited compared with CK. The growth curve trend of the 1.0% acid strain was similar to that of CK. The adjustment period was 4 h, the logarithmic phase was from 4 h to 36 h, it entered the stationary phase after 36 h to 48 h, and entered the decline phase after 48 h. The growth trends of 0.75% and 0.5% acid were similar and better than the CK treatment. The adjustment period was 4 h, the logarithmic phase was from 4 h to 32 h, it entered the stationary phase after 32 h to 36 h, and entered the decline phase after 36 h. This indicated that acid at a certain concentration could promote the growth of strain LP.1. Lactobacillus plantarum LP.1 had acidophilia and strong acid tolerance and could still grow and reproduce in the 1.5% high-acid medium.

[0058] Example 3: Test on 600 kg fermentation vats of Lactobacillus plantarum LP.1 fermented chili peppers

[0059] 200 μL of the cryopreserved Lactobacillus plantarum LP.1 bacterial liquid was inoculated into 100 mL of liquid medium (MRS medium) and cultured statically at 37°C for 48 h. The bacterial liquid concentration was adjusted to 1×10 8 CFU / mL, which was the Lactobacillus plantarum LP.1 seed liquid.

[0060] Fresh chili peppers were washed with water and neatly placed into a 600 kg vat, compacted with a pressing net, 6% (w / w) edible salt of the total system was added, water was added to the vat mouth, the vat was sealed, and daily maintenance of the vat mouth was done well. The Lactobacillus plantarum LP.1 seed liquid was mixed evenly with water, and the inoculation amount was 1×10 of the total system 6CFU / g. Add water to the brim of the vat, seal the vat, make marks, and place it in a dark place for fermentation for 60 days while doing daily maintenance. Use 500 ppm of sodium metabisulfite (calculated based on the residual amount of SO2) as a food additive as the positive control. The negative control group is the same as the experimental group in other treatments except that the test strain and sodium metabisulfite are not added. The fermented mature chili peppers are subjected to sensory evaluation and browning degree determination according to GB / T 10221-2021 / ISO 5492:2008 "Terms of Sensory Analysis", and the results are recorded in Table 2.

[0061] Table 2 Sensory Analysis of 600 kg Fermentation Vat of Chili Peppers

[0062] Group CK LP.1 Sodium metabisulfite Color and luster Tan, tending to black Golden yellow Golden yellow Aroma Sour aroma Rich sour aroma, altar aroma Sour aroma, altar aroma Taste Sour aroma, crispy and refreshing Sour aroma, crispy and refreshing Sour aroma, crispy and refreshing Appearance Normal Normal Normal

[0063] The results in Table 2 show that the fermented mature chili peppers with exogenous addition of LP.1 and 500 ppm of sodium metabisulfite have better and similar colors, both being golden yellow. The fermented mature chili peppers with exogenous addition of LP.1 have rich and harmonious sour taste and strong aroma in the vat. In the CK treatment, since no color protection agent was added externally, after about 15 days of fermentation, the color was dull, the aroma in the vat was weak, the sour aroma was weak, and the retention time was short. The comprehensive sensory evaluation was LP.1 ≥ sodium metabisulfite > CK. It verified the color protection advantage presented by Lactobacillus plantarum LP.1 during the large-scale fermentation process of chili peppers, and it can achieve large-scale industrial production.

[0064] Example 4 Shelf Life Test of Chili Peppers Fermented by Lactobacillus plantarum LP.1

[0065] Take the chili peppers fermented in Example 3, package the fermented products of chili peppers without adding additional additives, with 40% solids, adjust the total system salt to 6% with the old soup as the stock solution, and vacuum package. The packaged chili pepper products are placed at room temperature, 30 °C and 50 °C for accelerated shelf life testing for a total of 60 days. Samples are taken every 15 days for browning degree determination, and samples are taken on the 60th day for color difference testing simultaneously to verify the differences in the color protection effects of each treatment on chili pepper products. The results are recorded in Figure 5 and Table 3.

[0066] Figure 3The results showed that after storage at room temperature for 60 days, the browning degree of LP.1 was 0.269 Abs, that of 500 ppm sodium metabisulfite was 0.393 Abs, and that of the CK treatment was 0.439 Abs. The browning degree of the CK treatment was about 1.632 times higher than that of LP.1, and the 500 ppm sodium metabisulfite treatment was about 1.461 times higher than the LP.1 treatment. After storage at 37 °C for 60 days, the browning degree of LP.1 was 0.375 Abs, that of 500 ppm sodium metabisulfite was 0.457 Abs, and that of the CK treatment was 0.736 Abs. The browning degree of the CK treatment was about 1.923 times higher than that of LP.1, and the 500 ppm sodium metabisulfite treatment was about 1.219 times higher than the LP.1 treatment. After storage at 50 °C for 60 days, the browning degree of LP.1 was 0.745 Abs, that of 500 ppm sodium metabisulfite was 0.956 Abs, and that of the CK treatment was 1.57 Abs. The browning degree of the CK treatment was about 2.107 times higher than that of LP.1, and the 500 ppm sodium metabisulfite treatment was about 1.283 times higher than the LP.1 treatment. Under the three conditions of room temperature, 37 °C, and 50 °C, the browning degree of LP.1 was the smallest, that of 500 ppm sodium metabisulfite was slightly larger, and that of the CK treatment was the largest. It can be seen that LP.1 has a better color protection effect under both room temperature and accelerated shelf-life conditions, and the color protection effect is better than that of 500 ppm sodium metabisulfite.

[0067] Table 3 Color difference analysis of Capsicum frutescens L. during accelerated shelf life under different treatments

[0068]

[0069]

[0070] Note: CK is the blank control; △L represents the difference in L* between two samples. If it is positive, it means the test sample is lighter (whiter / brighter) than the standard sample. If △L is negative, it means the test sample is darker (blacker / darker) than the standard sample; △a represents the difference in a* between two samples. If it is positive, it means the test sample is redder (more red) than the standard sample. If △a is negative, it means the test sample is greener (more green) than the standard sample; if △b is positive, it means the test sample is yellower (more yellow). △b represents the difference in b* between two samples. If it is negative, it means the test sample is bluer (more blue) than the standard sample; △E is the total color difference. It does not represent the direction of color difference deviation. The larger the value, the greater the color difference.

[0071] Table 3 data shows that under three conditions of normal temperature, 37 °C, and 50 °C, the CK group is darker than the LP.1 group. LP.1 is greener and yellower. ΔE (LP.1 compared to CK, normal temperature) is 7.89, and the color difference is strong. ΔE (LP.1 compared to CK, 37 °C) is 10.55, and the color difference is strong. ΔE (LP.1 compared to CK, 50 °C) is 12.11, and the color difference at 50 °C is extremely strong. When comparing the 500 ppm sodium metabisulfite group with the LP.1 treatment group, under three conditions of normal temperature, 37 °C, and 50 °C, the 500 ppm sodium metabisulfite treatment group is darker, while LP.1 is greener and yellower. ΔE (LP.1 compared to 500 ppm sodium metabisulfite, normal temperature) is 3.47, and the color difference is obvious. ΔE (LP.1 compared to 500 ppm sodium metabisulfite, 37 °C) is 3.00, and the color difference is obvious. ΔE (LP.1 compared to 500 ppm sodium metabisulfite, 50 °C) is 3.89, and the color difference at 50 °C is obvious. The b* color difference between LP.1 and 500 ppm sodium metabisulfite under normal temperature treatment is not obvious, indicating that the color protection effect of LP.1 can be comparable to that of 500 ppm sodium metabisulfite. Lactobacillus plantarum LP.1 has an antioxidant and color protection effect and can replace the use of the chemical antioxidant sodium metabisulfite in the fermentation application of chili peppers.

[0072] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A strain of Lactobacillus plantarum ( Lactobacillus plantarum ) LP.1, characterized in that, The deposit number of the Lactobacillus plantarum LP.1 is CGMCC No. 30505.

2. A fermentation agent, characterized in that: The fermentation agent comprises the Lactobacillus plantarum as claimed in claim 1.

3. Application of the plant lactobacillus according to claim 1 or the fermentation agent according to claim 2 in pepper fermentation, characterized in that: The pepper is chili pepper.

4. The use according to claim 3, characterized in that The application is to maintain the color of pepper.

5. A method for fermenting chili pepper, characterized in that: The method is a method for adding the plant lactobacillus described in claim 1 or the fermentation agent described in claim 2 to chili pepper for fermentation.

6. The method according to claim 5, characterized in that The inoculation time of the plant lactobacillus or fermentation bacteria agent is the initial stage of fermentation.

7. The method according to any one of claims 5 or 6, characterized in that: The inoculation amount of the plant lactobacillus is 10 4 -10 8 CFU / g.

8. The method according to any one of claims 5 or 6, characterized in that: The salt concentration added during the fermentation process is 0%-10% (w / w).

9. The method according to any one of claims 5 or 6, characterized in that: The fermentation time is 30-90 days.

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