Method for improving flavor of pear juice based on synergistic fermentation of compound lactic acid bacteria

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a pear juice flavor improvement method based on synergistic fermentation of compound lactic acid bacteria. The invention relates to a pear juice flavor improvement method based on synergistic fermentation of compound lactic acid bacteria. The method comprises the following steps: S1, cleaning Xueqing pears, dicing, juicing and filtering to obtain pear juice; s2, pectinase is added into the pear juice obtained in the S1 for enzymolysis, the pear juice after enzymolysis is obtained, and then the pear juice is heated, sterilized and cooled; s3, adding compound lactic acid bacteria freeze-dried powder into the fruit juice subjected to enzymolysis for strain inoculation, and then adding sugar to obtain pear juice with the sugar degree of 6-8%; and fermenting the pear juice to obtain the pear juice cooperatively fermented by the compound lactic acid bacteria. The method can improve flavor and viable organism survival rate, and compound fermentation enhances functionality and production efficiency and improves taste stability.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a method for improving the flavor of pear juice based on composite lactic acid bacteria synergistic fermentation. Background Art

[0002] Pear juice beverage is a natural juice beverage made from pear fruit. It is highly favored by consumers because it is rich in nutrients such as polyphenols, dietary fiber and minerals. However, traditional pear juice beverages have a single flavor, mainly relying on the aroma components of the pear fruit itself, lacking a sense of hierarchy, and are prone to produce a ripe taste after high-temperature sterilization, resulting in a decrease in taste quality. In addition, the bioavailability of polyphenols in the pear juice matrix is ​​low, and it lacks active ingredients such as probiotics, making it difficult to meet consumers' health needs for functional beverages.

[0003] Lactic acid bacteria are the most representative probiotics. They acidify food by rapidly synthesizing organic acids, thereby preventing contamination by harmful microorganisms and extending the storage time of food. Lactic acid bacteria have traditionally been widely used as natural food biological preservatives. Plant lactic acid bacteria beverages do not contain dairy ingredients, eliminating the risk of problems such as lactose intolerance. At the same time, plant lactic acid bacteria beverages can provide a variety of nutrients. Polyphenols in plants can act as prebiotics to promote the growth of human intestinal flora and their adhesion to intestinal cells. Lactic acid bacteria fermentation can also increase the physiological activity and absorption rate of polyphenols. Therefore, the development of functional lactic acid bacteria products has gradually become a research hotspot.

[0004] In recent years, pear lactobacillus beverages have gradually become a hot spot in the market, endowing pear juice with unique flavor and functional characteristics through lactobacillus metabolism. However, the prior art mostly uses a single lactobacillus (such as Lactobacillus bulgaricus or Streptococcus thermophilus) for fermentation, and its metabolic pathway is limited, resulting in a single flavor substance spectrum, obvious sourness and astringency of the product, and poor taste coordination. At the same time, single strain fermentation is difficult to balance the inherent fruity aroma of pear juice and fermented frankincense, and is prone to produce irritating flavor substances such as excessive acetic acid, and has limited biotransformation ability for components such as polyphenols and dietary fiber, making it difficult to give full play to the nutritional value of pear juice.

[0005] In view of the above problems, the present invention proposes a method for preparing a pear juice beverage based on the synergistic fermentation of composite lactic acid bacteria. Through the metabolic complementarity of Lactobacillus rhamnosus and Lactobacillus acidophilus, the generation efficiency of flavor substances and functional ingredients is significantly improved, the organic fusion of pear juice fruity aroma and fermented frankincense is achieved, and at the same time the bioavailability of polyphenols and the survival rate of live bacteria are improved, giving the product rich flavor levels and prebiotic functions. Summary of the invention

[0006] In view of the shortcomings and problems in the prior art, the present invention provides a method for improving the flavor of pear juice based on composite lactic acid bacteria synergistic fermentation, comprising the following steps:

[0007] S1: washing, cutting, and juicing snow green pears, and filtering to obtain pear juice;

[0008] S2: adding pectinase to the pear juice obtained in S1 for enzymolysis to obtain enzymolyzed pear juice, and then heating and sterilizing the juice and then cooling the juice;

[0009] S3: adding the compound lactic acid bacteria freeze-dried powder to the enzymatically hydrolyzed fruit juice for bacterial inoculation, and then adding sugar to obtain pear juice with a sugar content of 6% to 8%; and then fermenting the pear juice to obtain pear juice fermented by compound lactic acid bacteria.

[0010] Furthermore, the amount of pectinase added in S2 is 30 mL, and the time of the enzymatic hydrolysis process is 30 min.

[0011] Furthermore, the heating time described in S2 is 15 minutes and the heating temperature is 90°C.

[0012] Furthermore, the inoculation amount of the inoculation process described in S3 is 0.25 g / L, and the composite lactic acid bacteria includes Lactobacillus rhamnosus and Lactobacillus acidophilus in a mass ratio of 1:1 to 1:3.

[0013] Furthermore, the fermentation time in S3 is 24 to 48 hours, and the fermentation temperature is 30 to 40°C.

[0014] Furthermore, the sugar described in S3 is any one of white sugar and sucrose.

[0015] Beneficial Effects

[0016] Multi-factor orthogonal optimization: Through multi-dimensional orthogonal experiments on temperature (30℃~40℃), time (24~48h), strain ratio (1:1, 1:2, 1:3), and sugar content (6%~8%), the optimal combination of process parameters was screened out, which significantly improved the efficiency of flavor substance production and the survival rate of live bacteria.

[0017] Synergistic effect of bacterial strains: Through the combined use of Lactobacillus rhamnosus and Lactobacillus acidophilus, the complementarity and synergistic effect of metabolic pathways are achieved, which significantly improves the efficiency of flavor substance production and solves the technical problems of single flavor and insufficient functionality of single bacterial strain fermentation.

[0018] Rich flavor layers: By optimizing fermentation parameters (such as bacterial strain ratio, sugar content, pH value, temperature and time), the organic fusion of pear juice fruity aroma and fermented milk aroma is achieved, which significantly reduces the sourness and astringency produced by single bacterial strain fermentation and improves the product's taste coordination and flavor layers.

[0019] Nutritional function enhancement: The synergistic fermentation of compound lactic acid bacteria significantly improves the bioavailability of polyphenols in pear juice, while generating a variety of functional metabolites, giving the product stronger prebiotic function and health value.

[0020] Improved production efficiency: The combination of enzymatic hydrolysis and composite bacterial fermentation shortens the fermentation cycle, improves production efficiency, and improves product texture and stability. DETAILED DESCRIPTION

[0021] The following will be combined with Examples 1 to 9 of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The present invention provides a method for improving the flavor of pear juice based on composite lactic acid bacteria cooperative fermentation, comprising the following steps:

[0023] S1: Select fruits that are moderately mature, flawless in appearance, uniform in size and fresh, wash the pears, cut the pulp into cubes, add them into a spiral juicer to squeeze, and filter through gauze to obtain clarified pear juice;

[0024] S2: adding pectinase, performing enzymolysis at room temperature, pasteurizing the pear juice after enzymolysis, and rapidly cooling the juice to room temperature with running cold water;

[0025] S3: adding freeze-dried powder of composite lactic acid bacteria, wherein the composite lactic acid bacteria is a combination of Lactobacillus rhamnosus and Lactobacillus acidophilus, adding white sugar to the pear juice to adjust the sugar content of the pear juice; placing the pear juice in a constant temperature box for fermentation, taking out the fermentation tank after fermentation, and obtaining pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0026] Example 1

[0027] S1: Select fruits that are moderately mature, flawless in appearance, uniform in size and fresh, wash the pears, cut the pulp into cubes of about 3 cm, add them into a spiral juicer to squeeze, and filter through 200-mesh gauze to obtain clarified pear juice;

[0028] S2: adding pectinase and performing enzymolysis for 30 min at room temperature, with the amount of pectinase added being 30 mg / L; heating the enzymolyzed pear juice to 90°C for pasteurization for 15 min, and rapidly cooling it to room temperature with running cold water;

[0029] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus in a ratio of 1:1; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 7%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 35°C for 36 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0030] Example 2

[0031] S1: The same steps as in Example 1;

[0032] S2: The same steps as in Example 1;

[0033] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus in a ratio of 1:1; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 6%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 30°C for 24 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0034] Example 3

[0035] S1: The same steps as in Example 1;

[0036] S2: The same steps as in Example 1;

[0037] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus in a ratio of 1:2; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 7%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 30°C for 48 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0038] Example 4

[0039] S1: The same steps as in Example 1;

[0040] S2: The same steps as in Example 1;

[0041] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus at a ratio of 1:3; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 8%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 30°C for 36 hours to obtain pear juice based on the coordinated fermentation of composite lactic acid bacteria.

[0042] Example 5

[0043] S1: The same steps as in Example 1;

[0044] S2: The same steps as in Example 1;

[0045] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus at a ratio of 1:3; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 6%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 30°C for 36 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0046] Example 6

[0047] S1: The same steps as in Example 1;

[0048] S2: The same steps as in Example 1;

[0049] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus in a ratio of 1:2; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 8%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 35°C for 24 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0050] Example 7

[0051] S1: The same steps as in Example 1;

[0052] S2: The same steps as in Example 1;

[0053] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus in a ratio of 1:2; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 6%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 40°C for 36 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0054] Example 8

[0055] S1: The same steps as in Example 1;

[0056] S2: The same steps as in Example 1;

[0057] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus at a ratio of 1:3; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 7%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 40°C for 24 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0058] Example 9

[0059] S1: The same steps as in Example 1;

[0060] S2: The same steps as in Example 1;

[0061] S3: adding freeze-dried powder of composite lactic acid bacteria at an inoculation rate of 0.25 g / L, wherein the composite lactic acid bacteria is compounded by Lactobacillus rhamnosus and Lactobacillus acidophilus in a ratio of 1:1; adding sucrose to the pear juice to adjust the sugar content of the pear juice to 8%; placing the pear juice in a constant temperature box for fermentation, and taking out the fermentation tank after fermentation at 40°C for 48 hours to obtain pear juice based on the synergistic fermentation of composite lactic acid bacteria.

[0062] The pear juices obtained by composite lactic acid bacteria cooperative fermentation in Examples 1 to 9 were subjected to sensory evaluation.

[0063] Table 1 Sensory evaluation results of Examples 1 to 9

[0064]

[0065]

[0066] According to the test results in Table 1, it can be seen that the lactic acid bacteria fermented pear juice prepared by the present invention reduces the sourness of the drink through the complementary metabolism of the strains, and the sensory score reaches 95 points (out of 100). The generation efficiency of flavor substances and functional ingredients is significantly improved, the organic fusion of pear juice fruity aroma and fermented frankincense is achieved, and the product is given a richer flavor level and probiotic function.

[0067] Through multi-factor orthogonal optimization experiments (temperature, time, strain ratio and sugar content, etc.), we screened out a set of optimal process parameter combinations, which effectively improved the efficiency of flavor generation and the survival rate of live bacteria. In addition, the combined use of Lactobacillus rhamnosus and Lactobacillus acidophilus successfully achieved the complementarity and synergistic enhancement of metabolic pathways, significantly improved the efficiency of flavor generation, and solved the problems of single flavor and insufficient functionality caused by single strain fermentation. By optimizing the fermentation parameters, the fruity aroma of pear juice and the fermented frankincense were organically integrated, successfully reducing the sourness and astringency produced by single strain fermentation, and improving the product's taste coordination and flavor layering. At the same time, the synergistic fermentation of composite lactic acid bacteria not only improved the bioavailability of polyphenols in pear juice, but also generated a variety of functional metabolites, enhancing the product's probiotic function and health value. By combining enzymatic treatment with composite strain fermentation, the fermentation cycle was shortened, the production efficiency was improved, and the texture and stability of the product were improved.

Claims

1. A method for improving the flavor of pear juice based on composite lactic acid bacteria synergistic fermentation, characterized in that: The following steps are included S1: washing, cutting, and juicing snow green pears, and filtering to obtain pear juice; S2: adding pectinase to the pear juice obtained in S1 for enzymolysis to obtain enzymolyzed pear juice, and then heating and sterilizing the juice and then cooling the juice; S3: adding the compound lactic acid bacteria freeze-dried powder to the enzymatically hydrolyzed fruit juice for bacterial inoculation, and then adding sugar to obtain pear juice with a sugar content of 6% to 8%; and then fermenting the pear juice to obtain pear juice fermented by compound lactic acid bacteria.

2. A method for improving the flavor of pear juice based on composite lactic acid bacteria synergistic fermentation according to claim 1, characterized in that: The amount of pectinase added in S2 is 30 mL, and the time during the enzymatic hydrolysis process is 30 min.

3. A method for improving the flavor of pear juice based on composite lactic acid bacteria synergistic fermentation according to claim 1, characterized in that: The heating time described in S2 is 15 min and the heating temperature is 90°C.

4. A method for improving the flavor of pear juice based on composite lactic acid bacteria synergistic fermentation according to claim 1, characterized in that: The inoculation amount of the inoculation process described in S3 is 0.25 g / L, and the composite lactic acid bacteria includes Lactobacillus rhamnosus and Lactobacillus acidophilus in a mass ratio of 1:1 to 1:

3.

5. A method for improving the flavor of pear juice based on composite lactic acid bacteria synergistic fermentation according to claim 1, characterized in that: The fermentation time in S3 is 24 to 48 hours, and the fermentation temperature is 30 to 40°C.

6. A method for improving the flavor of pear juice by co-fermentation with composite lactic acid bacteria according to claim 1, characterized in that: The sugar described in S3 is any one of white sugar and sucrose.

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