Domestication method of plant lactobacillus LP4 and hickory debittering processing method

Abstract

This invention discloses a method for the domestication of plant lactic acid bacteria LP4 and its de-astringency processing method for pecans. The invention involves dissolving plant lactic acid bacteria LP4 powder in water to activate the bacteria; initially propagating the bacteria using a liquid culture medium with shaking; and then inoculating the initially propagated bacteria into a domestication liquid culture medium for further propagation. After domestication, the plant lactic acid bacteria can significantly degrade the total flavonoids and condensed tannins in the inner seed coat of pecans, thereby reducing the astringency of the pecans. The plant lactic acid bacteria of this invention can grow using tannic acid in a glucose-free environment. After domestication, it can reproduce independently of glucose, using tannic acid as the sole carbon source, demonstrating a significant domestication effect.

Description

Technical Field

[0001] This invention relates to the field of pecan deastringency processing, specifically to a method for the domestication of plant lactic acid bacteria LP4 and its pecan deastringency processing method. Background Technology

[0002] Pecan (Caryacathayensis), belonging to the genus Carya Nutt. of the family Juglandaceae, is an economically unique tree species in China. Its kernels are rich in nutrients and highly valued by consumers. However, the seed coat, tightly bound to the pecan embryo, is rich in various astringent substances, such as phenolic compounds, flavonoids, and tannins. Therefore, pecans must be de-astringed before consumption. High-temperature boiling and high-pressure steaming are currently the most common methods for de-astringing pecan kernels. However, during this process, some high-nutrient substances dissolve in the boiling water and are lost, while high-concentration organic wastewater is generated, causing significant environmental pollution and significantly increasing processing costs. How to improve the de-astringency process for pecans is an urgent problem to be solved.

[0003] A method for removing astringency by co-fermenting plant lactic acid bacteria LP4 with pecan kernels has been proposed. However, most plant lactic acid bacteria cannot grow normally in solid tannic acid culture medium and require glucose as a carbon source, which is not efficient enough. This invention provides a method for domesticating plant lactic acid bacteria so that they can reproduce in liquid culture medium without glucose using tannic acid. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for the domestication of plant lactic acid bacteria LP4 and a method for deastringent processing of hickory nuts.

[0005] In a first aspect, the present invention provides a method for domesticating plant lactic acid bacteria LP4, wherein the method involves dissolving plant lactic acid bacteria LP4 powder in water to activate the plant lactic acid bacteria and awaken the strain;

[0006] The plant lactic acid bacteria were initially propagated by shaking a liquid culture medium; then the initially propagated plant lactic acid bacteria were inoculated into an acclimatized liquid culture medium for further propagation.

[0007] The acclimatization liquid culture medium comprises the following components: tannic acid, sodium nitrate, dipotassium hydrogen phosphate, magnesium sulfate, potassium chloride, ferrous sulfate, and graded glucose.

[0008] Preferably, the pH value of the acclimatization liquid culture medium is 7.

[0009] Preferably, the weight contents of each component in the acclimatization liquid culture medium are as follows: 1% tannic acid, 0.3% sodium nitrate, 0.1% dipotassium hydrogen phosphate, 0.05% magnesium sulfate, 0.05% potassium chloride, and 0.001% ferrous sulfate.

[0010] Preferably, the acclimatization liquid culture medium further includes glucose, wherein the glucose content is 0%-1% by weight.

[0011] Secondly, the present invention provides a method for removing astringency from hickory nuts, characterized in that the method involves thoroughly mixing and fermenting hickory nut kernels with plant lactic acid bacteria LP4 domesticated by the above method.

[0012] Preferably, the fermentation temperature is 37°C.

[0013] The beneficial effects of this invention are as follows:

[0014] The plant lactic acid bacteria of this invention can grow using tannic acid in a glucose-free environment. After domestication, they can reproduce without relying on glucose and using tannic acid as the sole carbon source, showing a significant domestication effect. Attached Figure Description

[0015] Figure 1 This is the result of the domestication of plant lactic acid bacteria LP4. Detailed Implementation

[0016] The following embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0017] The following examples use plant lactic acid bacteria LP4 as the reaction object. The 16S RNA sequencing sequence of the plant lactic acid bacteria is as follows:

[0018] CGCTGGCGGCGTGCCTAATACATGCAAGTCGAACGAACTCTGGTATTGATT

[0019] GGTGCTTGCATCATGATTTACATTTGAGTGAGTGGCGAACTGGTGAGTAAC

[0020] ACGTGGGAAACCTGCCCAGAAGCGGGGGATAACACCTGGAAACAGATGCT

[0021] AATACCGCATAACAACTTGGACCGCATGGTCCGAGTTTGAAAGATGGCTTC

[0022] GGCTATCACTTTTGGATGGTCCCGCGGCGTATTAGCTAGATGGTGAGGTAAC

[0023] GGCTCACCATGGCAATGATACGTAGCCGACCTGAGAGGGTAATCGGCCACA

[0024] TTGGGACTGAGACACGGCCCAAACTCCTACGGGAGGCAGCAGTAGGGAAT

[0025] CTTCCACAATGGACGAAAGTCTGATGGAGCAACGCCGCGTGAGTGAAGAA

[0026] GGGTTTCGGCTCGTAAAACTCTGTTGTTAAAGAAGAACATATCTGAGAGTA

[0027] ACTGTTCAGGTATTGACGGTATTTAACCAGAAAGCCACGGCTAACTACGTG

[0028] CCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTGTCCGGATTTATTGGG

[0029] CGTAAAGCGAGCGCAGGCGGTTTTTTAAGTCTGATGTGAAAGCCTTCGGCT

[0030] CAACCGAAGAAGTGCATCGGAAACTGGGAAACTTGAGTGCAGAAGAGGA

[0031] CAGTGGAACTCCATGTGTAGCGGTGAAATGCGTAGATATATGGAAGAACAC

[0032] CAGTGGCGAAGGCGGCTGTCTGGTCTGTAACTGACGCTGAGGCTCGAAAG

[0033] TATGGGTAGCAAACAGGATTAGATACCCTGGTAGTCCATACCGTAAACGATG

[0034] AATGCTAAGTGTTGGAGGGTTTCCGCCCTTCAGTGCTGCAGCTAACGCATT

[0035] AAGCATTCCGCCTGGGGAGTACGGCCGCAAGGCTGAAACTCAAAGGAATT

[0036] GACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCTACG

[0037] CGAAGAACCTTACCAGGTCTTGACATACTATGCAAATCTAAGAGATTAGAC

[0038] GTTCCCTTCGGGGACATGGATACAGGTGGTGCATGGTTGTCGTCAGCTCGT

[0039] GTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTATTATCAG

[0040] TTGCCAGCATTAAGTTGGGCACTCTGGTGAGACTGCCGGTGACAAACCGG

[0041] AGGAAGGTGGGGATGACGTCAAATCATCATGCCCCTTATGACCTGGGCTAC

[0042] ACACGTGCTACAATGGATGGTACAACGAGTTGCGAACTCGCGAGAGTAAG

[0043] CTAATCTCTTAAAGCCATTCTCAGTTCGGATTGTAGGCTGCAACTCGCCTAC

[0044] ATGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACG

[0045] TTCCCGGGCCTTGTACACACCGCCCGTCACACCATGAGAGTTTGTAACACC

[0046] CAAAGTCGGTGGGGTAACCTTTTAGGAACCAGCCGCCTAAGGTGGGACAG

[0047] ATGATTAGGGTGAAGTCGTACAG

[0048] Example 1: Domestication of plant-based lactic acid bacteria, including the following steps:

[0049] Step (1): The plant lactic acid bacteria LP4 powder of the present invention is dissolved in water at a ratio of 10wt%, coated on MRS solid culture medium plates and activated at 37°C to awaken the metabolic activity of the strain, repair cell damage, and restore its normal physiological function.

[0050] Step (2): Pick a single colony and place it in MRS liquid medium. Shake at 37°C and 200 rpm to propagate plant lactic acid bacteria. Incubate overnight to obtain seed culture.

[0051] Step (3): Inoculate the culture medium with 1% of the seed culture to further expand the propagation. Acclimate the culture at 37°C and 200 rpm for 24 hours. The culture medium formula is: 1% tannic acid, 0.3% sodium nitrate, 0.1% dipotassium hydrogen phosphate, 0.05% magnesium sulfate, 0.05% potassium chloride, 0.001% ferrous sulfate, and a gradient of glucose (0%-1%). The initial pH of the culture medium should be maintained at 7.

[0052] Step (4): After 24 hours, collect the domesticated plant lactic acid bacteria cells at the OD600 value and conduct post-domestication testing. Figure 1 This is the result of the domestication of plant lactic acid bacteria LP4. The plant lactic acid bacteria of this invention grow rapidly and have a long active period. The OD600 value measured after 24 hours of domestication culture was 1.66, indicating that the bacteria have been successfully domesticated and can grow in an environment of 1% tannic acid and 0% glucose. After domestication, plant lactic acid bacteria LP4 can reproduce independently of glucose, using tannic acid as the sole carbon source.

[0053] Example 2

[0054] The plant lactic acid bacteria domesticated in Example 1 were used to obtain a highly efficient deastringent plant lactic acid bacteria. When mixed with pecans and fermented overnight, the total flavonoids and condensed tannins in the pecan seed coat were effectively reduced.

Claims

1. A method for domesticating plant lactic acid bacteria LP4, characterized in that, The method involves dissolving plant lactic acid bacteria LP4 powder in water to activate the plant lactic acid bacteria; initially propagating the plant lactic acid bacteria by shaking a liquid culture medium; and then inoculating the initially propagated plant lactic acid bacteria into an acclimatization liquid culture medium for further propagation; the acclimatization liquid culture medium includes the following components: tannic acid, sodium nitrate, dipotassium hydrogen phosphate, magnesium sulfate, potassium chloride, ferrous sulfate, and gradient glucose.

2. The method according to claim 1, characterized in that, The pH value of the acclimatization liquid culture medium is 7.

3. The method according to claim 1, characterized in that, The weight contents of each component in the acclimatization liquid culture medium are as follows: 1% tannic acid, 0.3% sodium nitrate, 0.1% dipotassium hydrogen phosphate, 0.05% magnesium sulfate, 0.05% potassium chloride, and 0.001% ferrous sulfate.

4. The method according to claim 1, characterized in that, The acclimatization liquid culture medium also includes glucose, wherein the glucose content is 0%-1% by weight.

5. A method for removing astringency from hickory nuts, characterized in that, The method involves thoroughly mixing and fermenting plant lactic acid bacteria LP4, which has been domesticated according to any one of claims 1-4, with pecan kernels.

6. The method according to claim 5, characterized in that, The fermentation temperature is 37℃.

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