Making method of sour bamboo shoots for river snail rice noodles

Abstract

The invention discloses a making method of margarya melanioides rice noodles and sour bamboo shoots, and relates to the technical field of food fermentation. The making method of the margarya melanioides rice noodle sour bamboo shoots comprises the following steps: (1) preparing materials: washing, dicing, boiling and cooling fresh bamboo shoots, and putting the bamboo shoots into a clean container; (2) primary fermentation: adding water into a container to submerge the bamboo shoots, inoculating optimized lactobacillus plantarum, optimized leuconostoc citreum and optimized lactococcus lactis, sealing, and fermenting in a dark place to obtain a primary fermentation material; and (3) secondary fermentation: adding the fruit fermentation liquid into the primary fermentation material, sealing, and continuously fermenting in a dark place, thereby obtaining the product. According to the method, the strains are subjected to fermentation environment adaptability domestication firstly, the adaptability of the strains to the fermentation environment is improved, then the strains are used for fermentation, the stability of a fermentation system is enhanced through the fruit fermentation liquid, the problem that the quality of the sour bamboo shoots fermented through mixed bacteria is unstable is solved, growth of the strains can be promoted, and the yield of the sour bamboo shoots is increased. Furthermore, enrichment of various flavor substances is promoted, and the quality of the sour bamboo shoots is improved.

Description

Technical Field

[0001] The invention relates to the technical field of food fermentation, and in particular to a method for preparing snail rice noodle and sour bamboo shoots. Background Art

[0002] Sour bamboo shoots are an important side dish for all kinds of rice noodles, especially Liuzhou snail noodles. They can add a unique flavor to Liuzhou snail noodles and are deeply loved by the public. As the popularity of Liuzhou snail noodles continues to increase, the demand for sour bamboo shoots has also continued to rise in recent years. The existing fermentation methods for sour bamboo shoots are natural fermentation and inoculation fermentation. Natural fermentation is to wash the bamboo shoots with water, slice them, and then put them into salt water for natural fermentation. Usually, no external bacteria are added, and fermentation relies on microorganisms in the natural environment. The advantages are simple process, no need to add additional bacteria, and low cost. The disadvantages are that the fermentation process is difficult to control, the product quality is unstable, and there may be safety hazards such as contamination by harmful bacteria. Inoculation fermentation is to add specific fermentation bacteria to the bamboo shoots for fermentation. The fermentation process is controllable, the product is not easily contaminated by miscellaneous bacteria, and it is safer.

[0003] Existing large-scale sour bamboo shoots mainly adopt inoculation fermentation as the main method, and the fermentation bacteria inoculated can be a single strain or a mixed strain of multiple bacteria. Single strain fermentation has a relatively stable fermentation result due to the lack of competition or antagonism from other bacteria, that is, the sensory quality (such as taste, aroma) and texture of the fermented final product do not change much, but the flavor substances of single strain fermentation are not rich enough and the flavor is monotonous. There are also studies on the use of mixed strains of multiple bacteria for fermentation, such as patent CN 103445124 B, which is a method for making sour bamboo shoots by fermenting Lactobacillus delbrueckii and Lactobacillus pentosus together, and patent CN109275878 A, which is a method for making sour bamboo shoots by fermenting bifidobacterium, Lactococcus lactis and Lactobacillus plantarum to produce sour bamboo shoots. Although these can increase the flavor of sour bamboo shoots, different strains may compete with each other for nutrients (such as sugars), space and other growth factors in the same environment, resulting in unstable fermentation results. At the same time, the metabolites produced by different strains may affect the growth of other bacteria, destroy the balance of the bacterial community, affect the stability and fermentation effect of the entire fermentation system, and cause changes in the taste, aroma and texture of the final sour bamboo shoots. Existing studies have also confirmed this view, such as "Lin Lihua, Lu Anping, Chen Jing. Research progress on flavor substances and fermentation technology of sour bamboo shoots [J]. Journal of Food Safety and Quality, 2025, 16(3): 147–153". The study believes that the fermentation process of mixed strains may cause fluctuations in product quality due to the interaction between strains, making it difficult to achieve consistency. Therefore, mixed strain fermentation of sour bamboo shoots can sometimes produce a product with good flavor, but sometimes the flavor is insufficient, which needs further improvement. Summary of the Invention

[0004] In response to the above shortcomings, the present invention provides a method for producing sour bamboo shoots in snail rice noodle. First, each strain is individually acclimated to the fermentation environment to improve its adaptability to the fermentation environment before being used for fermentation. In the middle and late stages of fermentation, fruit fermentation liquid is used to enhance the stability of the fermentation system, thereby solving the problem of unstable quality of sour bamboo shoots fermented with mixed bacteria. The method of the present invention can achieve good synergy between the various strains, and each strain grows well, promoting the enrichment of various flavor substances, and achieving good quality stability of the sour bamboo shoots. The specific technical solution is as follows:

[0005] A method for preparing snail rice noodle and sour bamboo shoots, characterized by comprising the following steps:

[0006] (1) Preparation: Wash fresh bamboo shoots, cut into desired sizes, and blanch in boiling water for 3-5 minutes. Remove from heat, cool to room temperature, and place in a clean, sealed container.

[0007] (2) Primary fermentation: first, add sterilized water to the container to cover the bamboo shoots, then add 2-5% of the weight of the bamboo shoots after optimized Lactobacillus plantarum, 0.5-2% of the optimized Leuconostoc citrifolia, and 1-3% of the optimized Lactococcus lactis. The mixture is sealed and protected from light, and fermented at 28-35° C. for 5-7 days to obtain a primary fermentation material.

[0008] (3) Secondary fermentation: adding fruit fermentation liquid to the primary fermentation material, sealing, protecting from light, and continuing to ferment at 28-35° C. for 5-7 days to obtain the sour bamboo shoots.

[0009] Preferably, in step (2), the preparation method of the optimized Lactobacillus plantarum is:

[0010] S1. Inoculate Lactobacillus plantarum into MRS liquid culture medium and culture for 3-5 days, sterilize, filter, and collect the filtrate to obtain Lactobacillus plantarum metabolites; adopt the same method as that of Lactobacillus plantarum to culture Leuconostoc citrifolia and Lactococcus lactis to obtain Leuconostoc citrifolia metabolites and Lactococcus lactis metabolites, respectively;

[0011] S2. preparing an MRS solid culture medium A, wherein the MRS solid culture medium A is prepared by adding 5-10% of the metabolites of Leuconostoc citraceus and 10-15% of the metabolites of Lactococcus lactis to the MRS solid culture medium;

[0012] preparing an MRS solid culture medium B, wherein the MRS solid culture medium B is prepared by adding 15-20% of the metabolites of Leuconostoc citrina and 20-30% of the metabolites of Lactococcus lactis to the MRS solid culture medium;

[0013] S3, inoculating plant lactobacillus into the MRS solid culture medium A, culturing for 3-5 days, selecting bacterium colonies with good growth, inoculating into the MRS solid culture medium B, culturing for 3-5 days, selecting bacterium colonies with good growth, which are the optimized plant lactobacillus.

[0014] Preferably, in step (2), the preparation method of the optimized Leuconostoc citrinum is:

[0015] S1. Inoculating Leuconostoc citriodora into MRS liquid culture medium and culturing for 3-5 days, sterilizing, filtering, and collecting the filtrate to obtain Leuconostoc citriodora metabolites; culturing Lactobacillus plantarum and Lactococcus lactis respectively using the same method as that for Leuconostoc citriodora to obtain Lactobacillus plantarum metabolites and Lactococcus lactis metabolites, respectively;

[0016] S2. preparing an MRS solid culture medium C, wherein the MRS solid culture medium C is prepared by adding 20-25% of the metabolites of Lactobacillus plantarum and 10-15% of the metabolites of Lactococcus lactis to the MRS solid culture medium;

[0017] preparing an MRS solid culture medium D, wherein the MRS solid culture medium D is prepared by adding 30-40% of the metabolites of Lactobacillus plantarum and 20-30% of the metabolites of Lactococcus lactis to the MRS solid culture medium;

[0018] S3. Inoculate Leuconostoc citraceus into the MRS solid culture medium C, culture for 3-5 days, select colonies with good growth, and inoculate into the MRS solid culture medium D. After culturing for 3-5 days, select colonies with good growth, which are the optimized Leuconostoc citraceus.

[0019] Preferably, in step (2), the optimized method for preparing Lactococcus lactis is:

[0020] S1. Inoculating Lactococcus lactis into MRS liquid culture medium and culturing for 3-5 days, sterilizing, filtering, and collecting the filtrate to obtain Lactococcus lactis metabolites; culturing Lactobacillus plantarum and Leuconostoc citrinum by the same method as that for Lactococcus lactis to obtain Lactobacillus plantarum metabolites and Leuconostoc citrinum metabolites, respectively;

[0021] S2. preparing an MRS solid culture medium E, wherein the MRS solid culture medium E is prepared by adding 20-25% of the metabolite of Lactobacillus plantarum and 5-10% of the metabolite of Leuconostoc citraceus to the MRS solid culture medium;

[0022] preparing an MRS solid culture medium F, wherein the MRS solid culture medium F is prepared by adding 30-40% of the metabolites of Lactobacillus plantarum and 15-20% of the metabolites of Leuconostoc citrina to the MRS solid culture medium;

[0023] S3. Inoculate Lactococcus lactis into the MRS solid medium E, culture for 3-5 days, select the colonies with good growth, and inoculate into the MRS solid medium F. After culture for 3-5 days, select the colonies with good growth, which are the optimized Lactococcus lactis.

[0024] Preferably, the culture temperature is 28-35°C.

[0025] Preferably, in step (3), the preparation method of the fruit fermentation liquid is as follows: taking 20-25 parts of pineapple, 10-18 parts of dragon fruit, 5-17 parts of apple, 3-8 parts of sugar and 80-120 parts of water by weight; mixing the pulp of pineapple, dragon fruit and apple with sugar and water and crushing them, adding lactic acid bacteria and fermenting them naturally at room temperature for 3-6 days, stirring and ventilating for 10-20 minutes every 1-2 days during the fermentation period, and filtering after the fermentation is completed to obtain the fruit fermentation liquid.

[0026] Preferably, the added amount of the lactic acid bacteria is 0.2-0.5% of the weight of the mixed and crushed materials.

[0027] Preferably, in step (3), the amount of the fruit fermentation liquid added is 30-45% of the weight of the primary fermentation material.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention selects Lactobacillus plantarum, Leuconostoc citrifolia and Lactococcus lactis as bamboo shoot fermentation strains, first acclimates each strain to the fermentation environment to improve its adaptability to the fermentation environment, and then uses it for fermentation. In the middle and late stages of fermentation, fruit fermentation liquid is used to enhance the stability of the fermentation system, thereby solving the problem of unstable quality of sour bamboo shoots fermented by mixed bacteria. The method of the present invention can ensure good synergy between the strains, ensure good growth of the strains, promote the enrichment of various flavor substances, and ensure good quality stability of the sour bamboo shoots.

[0030] 2. The present invention adopts the method of progressively increasing the metabolites of the other two bacteria in the culture medium of one bacterium to carry out the adaptability domestication of the bacterial classification to the fermentation environment. For example, when optimizing plant lactobacillus, a small amount of metabolites of lemon leuconostoc and lactococcus lactis are first added to the plant lactobacillus culture medium, and a well-grown bacterium colony is preliminarily screened out. Then, the addition amount of the metabolites of lemon leuconostoc and lactococcus lactis is increased and the culture is continued. Thus, a highly adaptable bacterium colony is screened out as the final fermentation bacterium of the sour bamboo shoot. The adaptability of each bacterium to the fermentation environment can be improved, and good synergy is achieved between each bacterial classification. Each bacterial classification is well grown, and the flavor substances produced are rich in variety, thereby promoting the enrichment of multiple flavor substances and improving the quality of the sour bamboo shoot.

[0031] 3. fruit fermented liquid of the present invention is mainly obtained by lactic acid bacteria fermentation of pineapple, dragon fruit and apple, containing abundant vitamins, organic acid, antioxidant enzyme and protease, vitamin C wherein, vitamin E, coenzyme, organic acid can maintain the pH value stable in the fermentation process, avoid causing pH value violent change to affect microbial growth because of metabolite accumulation, simultaneously, catalase and superoxide dismutase can also alleviate the oxidative stress in the fermentation process, protect microbial cells from free radical damage, thereby improve fermentation efficiency and product quality, in addition, protease wherein can also improve protein conversion into various amino acids in the reaction system, has increased the generation of sour bamboo shoot flavor substances. Therefore, fruit fermented liquid can enhance the stability of fermentation system, thereby enhances the stability of fermentation process, improves fermentation efficiency, increases sour bamboo shoot flavor.

[0032] 4. The interaction between different strains of the present invention makes the fermentation process more efficient, reduces the competition of harmful microorganisms, shortens the fermentation time, reduces the production of black matter, and makes the sour bamboo shoots have a good color, do not turn black, and have high quality. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0034] Example 1

[0035] A method for preparing snail rice noodle and sour bamboo shoots, characterized by comprising the following steps:

[0036] (1) Preparation: Wash fresh bamboo shoots, cut into desired sizes, and blanch in boiling water for 3 min. Remove from heat, cool to room temperature, and place in a clean, sealed container.

[0037] (2) Optimizing bacterial strains: Lactobacillus plantarum, Leuconostoc citrinum, and Lactococcus lactis were selected as fermentation strains, and each strain was optimized as follows:

[0038] The optimization method of Lactobacillus plantarum is:

[0039] S1. Inoculate Lactobacillus plantarum into MRS liquid culture medium and culture for 3 days, sterilize, filter, and collect the filtrate to obtain Lactobacillus plantarum metabolites; culture Leuconostoc citrifolia and Lactococcus lactis using the same method as Lactobacillus plantarum to obtain Leuconostoc citrifolia metabolites and Lactococcus lactis metabolites, respectively; the inoculation amounts of Lactobacillus plantarum, Leuconostoc citrifolia, and Lactococcus lactis are all the same, namely 0.1% of the weight of the MRS liquid culture medium;

[0040] The formula of MRS liquid medium is: peptone 10.0 g / L, beef extract powder 10.0 g / L, yeast extract powder 5.0 g / L, glucose 20.0 g / L, Tween 80 1.0 mL / L, dipotassium hydrogen phosphate 2.0 g / L, sodium acetate 5.0 g / L, triammonium citrate 2.0 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.05 g / L, ferrous sulfate 0.05 g / L;

[0041] S2. Prepare MRS solid culture medium A, wherein 5% of a metabolite of Leuconostoc citraceus and 10% of a metabolite of Lactococcus lactis are added to MRS solid culture medium; and 15 g / L of agar is added to the above-mentioned MRS liquid culture medium.

[0042] Prepare MRS solid culture medium B, which is prepared by adding 15% of Leuconostoc citraceus metabolites and 20% of Lactococcus lactis metabolites to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0043] S3. Inoculate plant lactobacillus into the MRS solid culture medium A, culture for 3 days, select the bacterium with good growth, and inoculate into the MRS solid culture medium B. After culture for 3 days, select the bacterium with good growth to obtain the optimized plant lactobacillus.

[0044] The optimization method of Leuconostoc citrinum is:

[0045] S1. Inoculate Leuconostoc citriodora into MRS liquid culture medium and culture for 3 days, sterilize, filter, and collect the filtrate to obtain Leuconostoc citriodora metabolites; culture Lactobacillus plantarum and Lactococcus lactis respectively using the same method as Leuconostoc citriodora to obtain Lactobacillus plantarum metabolites and Lactococcus lactis metabolites, respectively; the formula of MRS liquid culture medium and the inoculation amount of each bacteria are the same as above;

[0046] S2. Prepare MRS solid culture medium C, which is prepared by adding 20% of Lactobacillus plantarum metabolites and 10% of Lactococcus lactis metabolites to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0047] Prepare MRS solid culture medium D, wherein 30% of Lactobacillus plantarum metabolites and 20% of Lactococcus lactis metabolites are added to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0048] S3. Inoculate Leuconostoc citraceus into MRS solid medium C, culture for 3 days, select colonies with good growth, and inoculate into MRS solid medium D. After culturing for 3 days, select colonies with good growth to obtain optimized Leuconostoc citraceus.

[0049] The optimization method for Lactococcus lactis is:

[0050] S1. Lactococcus lactis was inoculated into MRS liquid medium and cultured for 3 days, sterilized, filtered, and the filtrate was collected to obtain Lactococcus lactis metabolites; Lactobacillus plantarum and Leuconostoc citriodora were cultured using the same method as for Lactococcus lactis to obtain Lactobacillus plantarum metabolites and Leuconostoc citriodora metabolites, respectively; the formula of the MRS liquid medium and the inoculum amount of each bacterium were the same as above;

[0051] S2. Prepare MRS solid culture medium E, which is prepared by adding 20% of Lactobacillus plantarum metabolites and 5% of Leuconostoc citraceus metabolites to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0052] Prepare MRS solid culture medium F, wherein 30% of Lactobacillus plantarum metabolites and 15% of Leuconostoc citraceus metabolites are added to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0053] S3. Inoculate Lactococcus lactis into the MRS solid medium E, culture for 3 days, select colonies with good growth, and inoculate into the MRS solid medium F. After culturing for 3 days, select colonies with good growth to obtain optimized Lactococcus lactis.

[0054] The culture temperature involved in the above optimization process was 28°C.

[0055] (3) Primary fermentation: first, add sterilized water to the container to cover the bamboo shoots, then add 2% of the weight of the bamboo shoots after optimized Lactobacillus plantarum, 0.5% of the optimized Leuconostoc citrifolia, and 1% of the optimized Lactococcus lactis. The mixture is sealed and protected from light, and fermented at 28° C. for 5 days to obtain a primary fermentation material.

[0056] (4) Secondary fermentation: adding fruit fermentation liquid to the primary fermentation material in an amount of 30% by weight of the primary fermentation material, sealing, protecting from light, and continuing to ferment at 28°C for 5 days to obtain the sour bamboo shoots. The preparation method of the fruit fermentation liquid is as follows: taking 20 parts of pineapple, 10 parts of dragon fruit, 5 parts of apple, 3 parts of sugar and 80 parts of water by weight; mixing the pulp of pineapple, dragon fruit and apple with sugar and water and crushing them, adding lactic acid bacteria and fermenting them naturally at room temperature for 3 days, the amount of lactic acid bacteria added being 0.2% by weight of the mixed and crushed materials, stirring and ventilating for 10 minutes every other day during the fermentation period, and filtering after the fermentation is completed to obtain the fruit fermentation liquid.

[0057] Example 2

[0058] A method for preparing snail rice noodle and sour bamboo shoots, characterized by comprising the following steps:

[0059] (1) Preparation: Wash fresh bamboo shoots, cut into desired sizes, and blanch in boiling water for 5 min. Remove from heat, cool to room temperature, and place in a clean, sealed container.

[0060] (2) Optimizing bacterial strains: Lactobacillus plantarum, Leuconostoc citrinum, and Lactococcus lactis were selected as fermentation strains, and each strain was optimized as follows:

[0061] The optimization method of Lactobacillus plantarum is:

[0062] S1. Inoculating Lactobacillus plantarum into MRS liquid culture medium and culturing for 5 days, sterilizing, filtering, and collecting the filtrate to obtain Lactobacillus plantarum metabolites; culturing Leuconostoc citrinum and Lactococcus lactis respectively by the same method as that of Lactobacillus plantarum to obtain Leuconostoc citrinum metabolites and Lactococcus lactis metabolites, respectively; the inoculation amounts of Lactobacillus plantarum, Leuconostoc citrinum, and Lactococcus lactis were all the same, i.e., 0.3% of the weight of the MRS liquid culture medium;

[0063] The formula of MRS liquid medium is: peptone 10.0 g / L, beef extract powder 10.0 g / L, yeast extract powder 5.0 g / L, glucose 20.0 g / L, Tween 80 1.0 mL / L, dipotassium hydrogen phosphate 2.0 g / L, sodium acetate 5.0 g / L, triammonium citrate 2.0 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.05 g / L, ferrous sulfate 0.05 g / L;

[0064] S2. Prepare MRS solid culture medium A, wherein 10% of the metabolites of Leuconostoc citraceus and 15% of the metabolites of Lactococcus lactis are added to the MRS solid culture medium; the MRS solid culture medium is prepared by adding 15 g / L agar to the above-mentioned MRS liquid culture medium;

[0065] Prepare MRS solid culture medium B, wherein the MRS solid culture medium B is prepared by adding 20% of the metabolites of Leuconostoc citraceus and 30% of the metabolites of Lactococcus lactis to the MRS solid culture medium; the MRS solid culture medium is the same as above;

[0066] S3. Inoculate plant lactobacillus into the MRS solid culture medium A, culture for 5 days, select the bacterium with good growth, and inoculate into the MRS solid culture medium B. After culture for 5 days, select the bacterium with good growth to obtain the optimized plant lactobacillus.

[0067] The optimization method of Leuconostoc citrinum is:

[0068] S1. Inoculate Leuconostoc lemon into MRS liquid culture medium and culture for 5 days, sterilize, filter, and collect the filtrate to obtain Leuconostoc lemon metabolites; adopt the same method as described in Leuconostoc lemon to culture Lactobacillus plantarum and Lactococcus lactis, respectively, to obtain Lactobacillus plantarum metabolites and Lactococcus lactis metabolites; the formula of MRS liquid culture medium and the inoculation amount of each bacteria are the same as above;

[0069] S2. Prepare MRS solid culture medium C, wherein 25% of the metabolites of Lactobacillus plantarum and 15% of the metabolites of Lactococcus lactis are added to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0070] Prepare MRS solid culture medium D, wherein 40% of the metabolites of Lactobacillus plantarum and 30% of the metabolites of Lactococcus lactis are added to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0071] S3. Inoculate Leuconostoc citraceus into the MRS solid culture medium C, culture for 5 days, select colonies with good growth, and inoculate into the MRS solid culture medium D. After culturing for 5 days, select colonies with good growth to obtain optimized Leuconostoc citraceus.

[0072] The optimization method for Lactococcus lactis is:

[0073] S1, inoculating Lactococcus lactis into MRS liquid culture medium and culturing for 5 days, sterilizing, filtering, and collecting the filtrate to obtain Lactococcus lactis metabolites; adopting the same method as described in Lactococcus lactis to cultivate Lactobacillus plantarum and Leuconostoc citrinum, respectively, to obtain Lactobacillus plantarum metabolites and Leuconostoc citrinum metabolites, respectively; the formula of MRS liquid culture medium and the inoculation amount of each bacteria are the same as above;

[0074] S2. Prepare MRS solid culture medium E, wherein 25% of the metabolites of Lactobacillus plantarum and 10% of the metabolites of Leuconostoc citrina are added to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0075] Prepare MRS solid culture medium F, wherein 40% of the metabolites of Lactobacillus plantarum and 20% of the metabolites of Leuconostoc citrina are added to the MRS solid culture medium; the MRS solid culture medium is the same as above;

[0076] S3. Inoculate Lactococcus lactis into the MRS solid medium E, culture for 5 days, select colonies with good growth, and inoculate into the MRS solid medium F. After 5 days of culture, select colonies with good growth to obtain optimized Lactococcus lactis.

[0077] The culture temperature involved in the above optimization process was 35°C.

[0078] (3) Primary fermentation: first, add sterilized water to the container to cover the bamboo shoots, then add 5% of the weight of the bamboo shoots after optimized Lactobacillus plantarum, 2% of the optimized Leuconostoc citrifolia, and 3% of the optimized Lactococcus lactis. The mixture is sealed and protected from light, and fermented at 35° C. for 7 days to obtain a primary fermentation material.

[0079] (4) Secondary fermentation: adding fruit fermentation liquid to the primary fermentation material in an amount of 45% by weight of the primary fermentation material, sealing, protecting from light, and continuing to ferment at 35°C for 7 days to obtain the sour bamboo shoots. The preparation method of the fruit fermentation liquid is as follows: taking 25 parts of pineapple, 18 parts of dragon fruit, 17 parts of apple, 8 parts of sugar and 120 parts of water by weight; mixing the pulp of pineapple, dragon fruit and apple with sugar and water and crushing them, adding lactic acid bacteria and fermenting them naturally at room temperature for 6 days, the amount of lactic acid bacteria added being 0.5% by weight of the mixed and crushed materials, stirring and ventilating for 20 minutes every 2 days during the fermentation period, and filtering after the fermentation is completed to obtain the fruit fermentation liquid.

[0080] Example 3

[0081] A method for preparing snail rice noodle and sour bamboo shoots, characterized by comprising the following steps:

[0082] (1) Preparation: Wash fresh bamboo shoots, cut into desired sizes, and blanch in boiling water for 4 min. Remove from heat, cool to room temperature, and place in a clean, sealed container.

[0083] (2) Optimizing bacterial strains: Lactobacillus plantarum, Leuconostoc citrinum, and Lactococcus lactis were selected as fermentation strains, and each strain was optimized as follows:

[0084] The optimization method of Lactobacillus plantarum is:

[0085] S1. Inoculating Lactobacillus plantarum into MRS liquid culture medium and culturing for 4 days, sterilizing, filtering, and collecting the filtrate to obtain Lactobacillus plantarum metabolites; culturing Leuconostoc citrinum and Lactococcus lactis respectively by the same method as that of Lactobacillus plantarum to obtain Leuconostoc citrinum metabolites and Lactococcus lactis metabolites, respectively; the inoculation amounts of Lactobacillus plantarum, Leuconostoc citrinum, and Lactococcus lactis were all the same, i.e., 0.2% by weight of the MRS liquid culture medium;

[0086] The formula of MRS liquid medium is: peptone 10.0 g / L, beef extract powder 10.0 g / L, yeast extract powder 5.0 g / L, glucose 20.0 g / L, Tween 80 1.0 mL / L, dipotassium hydrogen phosphate 2.0 g / L, sodium acetate 5.0 g / L, triammonium citrate 2.0 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.05 g / L, ferrous sulfate 0.05 g / L;

[0087] S2. Prepare MRS solid culture medium A, wherein 7% of the metabolites of Leuconostoc citraceus and 12% of the metabolites of Lactococcus lactis are added to MRS solid culture medium; and 15 g / L of agar is added to the above-mentioned MRS liquid culture medium.

[0088] Prepare MRS solid culture medium B, wherein the MRS solid culture medium B is prepared by adding 18% of the metabolites of Leuconostoc citraceus and 25% of the metabolites of Lactococcus lactis to the MRS solid culture medium; the MRS solid culture medium is the same as above;

[0089] S3. Inoculate plant lactobacillus into the MRS solid culture medium A, culture for 4 days, select the bacterium colonies with good growth, and inoculate into the MRS solid culture medium B. After culture for 4 days, select the bacterium colonies with good growth to obtain the optimized plant lactobacillus.

[0090] The optimization method of Leuconostoc citrinum is:

[0091] S1. Inoculate Leuconostoc lemon into MRS liquid culture medium and culture for 4 days, sterilize, filter, and collect the filtrate to obtain Leuconostoc lemon metabolites; adopt the same method as described in Leuconostoc lemon to culture Lactobacillus plantarum and Lactococcus lactis, respectively, to obtain Lactobacillus plantarum metabolites and Lactococcus lactis metabolites; the formula of MRS liquid culture medium and the inoculation amount of each bacteria are the same as above;

[0092] S2. Prepare MRS solid culture medium C, wherein 22% of the metabolites of Lactobacillus plantarum and 12% of the metabolites of Lactococcus lactis are added to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0093] Prepare MRS solid culture medium D, wherein the MRS solid culture medium D is prepared by adding 35% of the metabolites of Lactobacillus plantarum and 25% of the metabolites of Lactococcus lactis to the MRS solid culture medium; the MRS solid culture medium is the same as above;

[0094] S3. Inoculate Leuconostoc citraceus into the MRS solid culture medium C, culture for 4 days, select colonies with good growth, and inoculate into the MRS solid culture medium D. After culturing for 4 days, select colonies with good growth to obtain optimized Leuconostoc citraceus.

[0095] The optimization method for Lactococcus lactis is:

[0096] S1, inoculating Lactococcus lactis into MRS liquid culture medium and culturing for 4 days, sterilizing, filtering, and collecting the filtrate to obtain Lactococcus lactis metabolites; adopting the same method as described in Lactococcus lactis to cultivate Lactobacillus plantarum and Leuconostoc citrinum, respectively, to obtain Lactobacillus plantarum metabolites and Leuconostoc citrinum metabolites, respectively; the formula of MRS liquid culture medium and the inoculation amount of each bacteria are the same as above;

[0097] S2. Prepare MRS solid culture medium E, wherein 22% of the metabolites of Lactobacillus plantarum and 8% of the metabolites of Leuconostoc citrina are added to MRS solid culture medium; the MRS solid culture medium is the same as above;

[0098] Prepare MRS solid culture medium F, wherein 35% of the metabolites of Lactobacillus plantarum and 18% of the metabolites of Leuconostoc citrina are added to the MRS solid culture medium; the MRS solid culture medium is the same as above;

[0099] S3. Inoculate Lactococcus lactis into the MRS solid medium E, culture for 4 days, select colonies with good growth, and inoculate into the MRS solid medium F. After 4 days of culture, select colonies with good growth to obtain optimized Lactococcus lactis.

[0100] The culture temperature involved in the above optimization process was 32°C.

[0101] (3) Primary fermentation: first, add sterilized water to the container to cover the bamboo shoots, then add 3% of the weight of the bamboo shoots after optimized Lactobacillus plantarum, 1% of the optimized Leuconostoc citrifolia, and 2% of the optimized Lactococcus lactis. The mixture is sealed and protected from light, and fermented at 32° C. for 6 days to obtain a primary fermentation material.

[0102] (4) Secondary fermentation: adding fruit fermentation liquid to the primary fermentation material in an amount of 40% by weight of the primary fermentation material, sealing, protecting from light, and continuing to ferment at 32°C for 6 days to obtain the sour bamboo shoots. The preparation method of the fruit fermentation liquid is as follows: taking 22 parts of pineapple, 15 parts of dragon fruit, 13 parts of apple, 6 parts of sugar and 100 parts of water by weight; mixing the pulp of pineapple, dragon fruit and apple with sugar and water and crushing them, adding lactic acid bacteria and fermenting them naturally at room temperature for 5 days, the amount of lactic acid bacteria added being 0.4% by weight of the mixed and crushed materials, stirring and ventilating for 15 minutes every 2 days during the fermentation period, and filtering after the fermentation is completed to obtain the fruit fermentation liquid.

[0103] Comparative Example 1: without step (2), that is, without optimizing Lactobacillus plantarum, Leuconostoc citrinum and Lactococcus lactis, and other steps are the same as those in Example 1.

[0104] Comparative Example 2: In step (4), no fruit fermentation liquid was added, and the other steps were the same as in Example 1.

[0105] Comparative Example 3: In step (4), the fruit fermentation liquid was not fermented by lactic acid bacteria, but was naturally fermented. The other steps were the same as those in Example 1.

[0106] After the fermentation was completed, the total acid, amino nitrogen content and nitrite content of the sour bamboo shoots of each embodiment and each comparative example were detected, wherein the total acid of the sour bamboo shoots was determined with reference to GB 12456-2021 "National Food Safety Standard Determination of Total Acid in Food", the nitrite of the sour bamboo shoots was determined with reference to GB 5009.33-2016 "National Food Safety Standard Determination of Nitrite and Nitrate in Food", and the amino nitrogen of the sour bamboo shoots was determined with reference to GB 5009.235-2016 "National Food Safety Standard Determination of Amino Acid Nitrogen in Food", and a sensory evaluation was performed. The results are shown in Table 1:

[0107] Table 1

[0108]

[0109] Table 1 shows that the sour bamboo shoots prepared by the method of the present invention have high total acid and amino nitrogen contents, low nitrite content, and high sensory evaluation, indicating that the optimized mixed bacteria and fruit fermentation liquid can increase the acidity and amino acid content of the sour bamboo shoots and reduce the nitrite content. At the same time, the same color and smell can be obtained each time the preparation is carried out under the same conditions, indicating stability. The quality of the sour bamboo shoots after fermentation by the method of the present invention does not fluctuate much and has good stability.

[0110] The volatile components in the sour bamboo shoots after fermentation (10 days) were determined by SPME-GC-MS technology. The results are shown in Table 2:

[0111] Table 2

[0112]

[0113]

[0114] Note: - indicates not detected, + indicates detected.

[0115] Table 2 shows that the types of volatile substances detected in the sour bamboo shoots prepared by the method of the present invention are more than those in the comparative examples, indicating that the present invention can promote the enrichment of various flavor substances in the sour bamboo shoots.

[0116] In summary, the present invention selects Lactobacillus plantarum, Leuconostoc citrifolia and Lactococcus lactis as bamboo shoot fermentation strains, first performs adaptability acclimation on each strain to the fermentation environment to improve its adaptability to the fermentation environment, and then uses it for fermentation, and adopts fruit fermentation liquid to enhance the stability of the fermentation system in the middle and late stages of fermentation, thereby solving the problem of unstable quality of sour bamboo shoots fermented by mixed bacteria. The method of the present invention can achieve good synergistic effect between the strains, and each strain grows well, thereby promoting the enrichment of multiple flavor substances and achieving good quality stability of the sour bamboo shoots.

[0117] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for making snail rice noodle and sour bamboo shoots, characterized in that: The following steps are involved: (1) Preparation: Wash fresh bamboo shoots, cut into desired sizes, blanch in boiling water, remove from heat, cool to room temperature, and place in a clean, sealed container; (2) Primary fermentation: first, add sterilized water to the container to cover the bamboo shoots, then add 2-5% of the weight of the bamboo shoots after optimized Lactobacillus plantarum, 0.5-2% of the optimized Leuconostoc citrifolia, and 1-3% of the optimized Lactococcus lactis. The mixture is sealed and protected from light, and fermented at 28-35° C. for 5-7 days to obtain a primary fermentation material. (3) Secondary fermentation: adding fruit fermentation liquid to the primary fermentation material, sealing, protecting from light, and continuing to ferment at 28-35° C. for 5-7 days to obtain the sour bamboo shoots.

2. The method for making snail rice noodle and sour bamboo shoots according to claim 1, wherein: In step (2), the preparation method of the optimized plant lactobacillus is: S1. Inoculate Lactobacillus plantarum into MRS liquid culture medium and culture for 3-5 days, sterilize, filter, and collect the filtrate to obtain Lactobacillus plantarum metabolites; adopt the same method as that of Lactobacillus plantarum to culture Leuconostoc citrifolia and Lactococcus lactis to obtain Leuconostoc citrifolia metabolites and Lactococcus lactis metabolites, respectively; S2. preparing an MRS solid culture medium A, wherein the MRS solid culture medium A contains 5-10% of the metabolites of Leuconostoc citrina and 10-15% of the metabolites of Lactococcus lactis; preparing an MRS solid culture medium B, wherein the MRS solid culture medium B contains 15-20% of the metabolites of Leuconostoc citrina and 20-30% of the metabolites of Lactococcus lactis; S3, inoculating plant lactobacillus into the MRS solid culture medium A, culturing for 3-5 days, selecting bacterium colonies with good growth, inoculating into the MRS solid culture medium B, culturing for 3-5 days, selecting bacterium colonies with good growth, which are the optimized plant lactobacillus.

3. The method for making snail rice noodle and sour bamboo shoots according to claim 1, wherein: In step (2), the preparation method of the optimized Leuconostoc citrinum is as follows: S1. Inoculating Leuconostoc citriodora into MRS liquid culture medium and culturing for 3-5 days, sterilizing, filtering, and collecting the filtrate to obtain Leuconostoc citriodora metabolites; culturing Lactobacillus plantarum and Lactococcus lactis respectively using the same method as that for Leuconostoc citriodora to obtain Lactobacillus plantarum metabolites and Lactococcus lactis metabolites, respectively; S2. preparing an MRS solid culture medium C containing 20-25% of the metabolites of Lactobacillus plantarum and 10-15% of the metabolites of Lactococcus lactis; preparing an MRS solid culture medium D containing 30-40% of the metabolites of Lactobacillus plantarum and 20-30% of the metabolites of Lactococcus lactis; S3. Inoculate Leuconostoc citraceus into the MRS solid culture medium C, culture for 3-5 days, select colonies with good growth, and inoculate into the MRS solid culture medium D. After culturing for 3-5 days, select colonies with good growth, which are the optimized Leuconostoc citraceus.

4. The method for making snail rice noodle and sour bamboo shoots according to claim 1, wherein: In step (2), the preparation method of the optimized Lactococcus lactis is: S1. Inoculating Lactococcus lactis into MRS liquid culture medium and culturing for 3-5 days, sterilizing, filtering, and collecting the filtrate to obtain Lactococcus lactis metabolites; culturing Lactobacillus plantarum and Leuconostoc citrinum by the same method as that for Lactococcus lactis to obtain Lactobacillus plantarum metabolites and Leuconostoc citrinum metabolites, respectively; S2. preparing an MRS solid culture medium E containing 20-25% of the metabolites of Lactobacillus plantarum and 5-10% of the metabolites of Leuconostoc citrea; preparing an MRS solid culture medium F, wherein the MRS solid culture medium F contains 30-40% of the metabolites of Lactobacillus plantarum and 15-20% of the metabolites of Leuconostoc citrina; S3. Inoculate Lactococcus lactis into the MRS solid medium E, culture for 3-5 days, select the colonies with good growth, and inoculate into the MRS solid medium F. After culture for 3-5 days, select the colonies with good growth, which are the optimized Lactococcus lactis.

5. The method for making snail rice noodle and sour bamboo shoots according to claim 2, 3 or 4, characterized in that: The culture temperature is 28-35°C.

6. The method for making snail rice noodle and sour bamboo shoots according to claim 1, characterized in that: In step (3), the preparation method of the fruit fermentation liquid is as follows: taking 20-25 parts of pineapple, 10-18 parts of dragon fruit, 5-17 parts of apple, 3-8 parts of sugar and 80-120 parts of water by weight; mixing the pulp of pineapple, dragon fruit and apple with sugar and water and crushing them, adding lactic acid bacteria and fermenting them naturally at room temperature for 3-6 days, stirring and ventilating for 10-20 minutes every 1-2 days during the fermentation period, and filtering after the fermentation is completed to obtain the fruit fermentation liquid.

7. The method for making snail rice noodle and sour bamboo shoots according to claim 6, characterized in that: The added amount of the lactic acid bacteria is 0.2-0.5% of the weight of the mixed and crushed materials.

8. The method for making snail rice noodle and sour bamboo shoots according to claim 1, characterized in that: In step (3), the added amount of the fruit fermentation liquid is 30-45% of the weight of the primary fermentation material.

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