Active lactobacillus fermented tea with enhanced flavor and preparation method thereof

Abstract

The invention provides flavor-enhanced active lactic acid bacteria fermented tea and a preparation method thereof, and the active lactic acid bacteria fermented tea comprises the following raw materials in percentage by mass: 0.2%-1% of tea leaves, 0.01%-0.05% of compound enzyme, 0.01%-0.05% of zymophyte, 1%-5% of a carbon source, 0.01%-0.1% of yeast powder and the balance of water, wherein the zymophyte is casei paracasei. By optimizing the formula and special process conditions, the problems that the existing tea beverage contains few tea leaves, the aroma of the beverage is lost after fermentation, the viable count in the finished product is small and the like are effectively avoided, so that the active lactobacillus fermented tea beverage which is balanced in nutrition, rich in aroma and good in stability is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of tea beverages, and in particular to active lactic acid bacteria fermented tea with enhanced flavor and a preparation method thereof. Background Art

[0002] Lactic acid bacteria, Gram-positive bacteria, have no spores, are non-motile or only a few are motile, and can be divided into two forms: rod-shaped and spherical. Lactic acid bacteria can produce a variety of lactic acid by fermenting carbohydrates in the body, thereby giving fermented products a special flavor and improving the nutritional value and health benefits of the products. Studies have shown that most lactic acid bacteria have important physiological functions. Lactic acid bacteria have beneficial effects in preventing and treating lactose intolerance, preventing diarrhea, preventing peptic ulcers, inhibiting other pathogens, enhancing the body's immunity, degrading cholesterol, and preventing cancer and tumors. With the strengthening of the understanding and research on the role and function of lactic acid bacteria, its unique nutritional effects and physiological activities have gradually been widely developed and utilized, and it has been widely used in major important fields such as food industry, pharmaceutical industry, agriculture and animal husbandry. Lactic acid bacteria are most widely used in the food fermentation industry, such as kimchi, yogurt, sausage, cheese, etc. in life. While giving food a special flavor, lactic acid bacteria can also degrade macromolecules in food, which is beneficial to the body's absorption and improves the body's nutrient absorption rate of food.

[0003] According to GB / T 30766 Tea Classification, tea can be divided into six categories: green tea, black tea, oolong tea, white tea, dark tea, and yellow tea. Black tea has a dark and glossy appearance, bright red soup color, high and sharp aroma, and a sweet and fresh taste. It is characterized by flower and fruit aroma. Famous black teas also have honey aroma, sweet potato aroma, and malt aroma. The taste is strong and fresh. Some black teas also have a refreshing taste. Representative categories include Keemun black tea, Dianhong tea, and Zhengshan Xiaozhong. Therefore, black tea as the base material of tea beverages has a unique taste and smell.

[0004] According to GB / T 21733-2008, tea beverages mainly refer to liquid beverages made from water extracts of tea leaves or their concentrates, tea powder, etc. as the main raw materials, and water, sugar, acidulants, edible flavors, fruit juices, dairy products, plant (grain) extracts, etc. can be added. According to the product flavor, tea beverages are mainly divided into tea soup, flavored tea beverages, compound tea beverages and tea concentrates, among which tea soup includes black tea beverages, green tea beverages, oolong tea beverages, etc. The fermented tea beverages obtained in the present invention are mainly black tea beverages. According to the national standard description, black tea beverage products should meet certain technical requirements, including that raw and auxiliary materials, food additives and hygiene indicators should meet the provisions of relevant standards; in terms of sensory aspects, they should have the color, aroma and taste that the product should have, and turbidity or precipitation caused by tea components is allowed, and there are no foreign impurities visible to normal vision; the tea polyphenol content of black tea beverages is ≥300mg / kg, and the caffeine content is ≥40mg / kg.

[0005] Although there are many varieties of pre-made bottled tea beverages on the market, there are fewer lactic acid bacteria fermented tea beverages, and there are not many related studies. Currently, most lactic acid bacteria fermented beverages use fresh milk, milk powder or fruit and vegetable juice as raw materials. There are relatively few beverages that are directly fermented with tea powder or tea concentrate as substrates. The content of tea ingredients in the few tea fermented beverages is generally low. Therefore, using tea as a substrate for lactic acid fermentation and retaining the active lactic acid bacteria therein, while giving full play to the functions of tea and lactic acid bacteria, a functional beverage with both flavor and nutrition will be obtained.

[0006] However, most of the current academic research focuses on mixed fermentation of multiple strains. The products developed are rich in nutrition and unique in flavor, but the process operation is complicated and easily contaminated by foreign bacteria during production, which requires strict control; in addition, studies have shown that tea polyphenols in tea have a certain antibacterial effect, which is not conducive to the growth and reproduction of microorganisms in fermented beverages and the retention of active lactic acid bacteria during the shelf life; nutrients such as carbon sources and nitrogen sources in tea are not sufficient for the growth and reproduction of microorganisms, and nutrients such as sugar need to be added; and in the processing of existing fermented tea beverages, the flavor substances in the tea are usually lost. Summary of the invention

[0007] In view of the problems existing in the production of existing fermented tea beverages, the object of the present invention is to provide an active lactic acid bacteria fermented tea with enhanced flavor and a preparation method thereof.

[0008] To achieve the above-mentioned object, the present invention provides an active lactic acid bacteria fermented tea with enhanced flavor. The raw materials thereof include, by mass percentage, 0.2%-1% of tea leaves, 0.01%-0.05% of complex enzyme, 0.01%-0.05% of fermentation bacteria, 1%-5% of carbon source, 0.01%-0.1% of yeast powder, and the balance of water; wherein the fermentation bacteria is Lactobacillus paracasei.

[0009] In the above-mentioned active lactic acid bacteria fermented tea with enhanced flavor, preferably, the fermenting bacteria is the strain Lactobacillus paracasei K56.

[0010] In the above-mentioned active lactic acid bacteria fermented tea with enhanced flavor, preferably, the carbon source includes at least one of glucose, sucrose and fructose.

[0011] In the above-mentioned active lactic acid bacteria fermented tea with enhanced flavor, preferably, the tea leaves are black tea.

[0012] In the above-mentioned active lactic acid bacteria fermented tea with enhanced flavor, preferably, the pH value of the active lactic acid bacteria fermented tea is 4.0-4.1.

[0013] In the present invention, all raw materials can be obtained commercially, and the performance indicators of each raw material meet the requirements of relevant quality standards.

[0014] The present invention also provides a method for preparing the above-mentioned flavor-enhanced active lactic acid bacteria fermented tea, which comprises the following steps:

[0015] Extracting tea leaves with water to obtain tea base;

[0016] Adding a carbon source and yeast powder to the tea base material, and then adding a composite enzyme for enzymolysis to obtain an enzymolysis solution;

[0017] The enzymolysis solution is sterilized and cooled, and then fermentation bacteria is added to perform fermentation to obtain the active lactic acid bacteria fermented tea.

[0018] After the tea base is enzymatically hydrolyzed, the content of catechin compounds is significantly reduced, thereby reducing its bitter taste, improving the taste of the tea beverage, and benefiting the fermentation of the bacteria. The obtained fermented tea beverage is rich in active lactic acid bacteria and has balanced nutrition.

[0019] In the method for preparing the above-mentioned active lactic acid bacteria fermented tea with enhanced flavor, preferably, the enzymolysis temperature is 25-60° C. and the enzymolysis time is 1-5 h.

[0020] In the method for preparing the above-mentioned flavor-enhanced active lactic acid bacteria fermented tea, preferably, the sterilization temperature is 75-95° C. and the sterilization time is 5-30 min.

[0021] In the method for preparing the above-mentioned flavor-enhanced active lactic acid bacteria fermented tea, preferably, the fermentation temperature is 30-45° C. and the fermentation time is 18-48 hours.

[0022] In the method for preparing the above-mentioned flavor-enhanced active lactic acid bacteria fermented tea, preferably, the extraction temperature is 60-90° C. and the extraction time is 5-30 min.

[0023] According to a specific embodiment of the present invention, preferably, the method for preparing the above-mentioned flavor-enhanced active lactic acid bacteria fermented tea comprises the following steps:

[0024] (1) Obtaining tea base material: weigh an appropriate amount of water, add a large amount of black tea leaves in proportion, soak at 80° C. for 10 min, filter the tea residue through a filter cloth, and cool to room temperature to obtain a tea base material;

[0025] (2) Enzymatic hydrolysis: add a carbon source and yeast powder to the tea base, then add a dissolved complex enzyme solution in a certain proportion, and perform enzymatic hydrolysis at 40° C. for 1 h to obtain an enzymatic hydrolyzate;

[0026] (3) Fermentation: sterilize the enzymatic hydrolyzate at 85° C. for 30 min, cool it, add Lactobacillus paracasei K56 to the sterilized and cooled liquid according to a certain proportion, and ferment it at 37° C. for 24 h to obtain the active lactic acid bacteria fermented tea with enhanced flavor.

[0027] In the present invention, the equipment used in the production process are all well-known equipment and related technologies in the field.

[0028] The present invention successfully proposes an active lactic acid bacteria fermented tea beverage with enhanced flavor from the perspectives of tea raw materials, beverage formula and production process.

[0029] The technical solution provided by the present invention has the following beneficial effects:

[0030] The present invention effectively avoids the problems of less tea ingredients in current tea beverages and loss of beverage aroma after fermentation through an optimal formula and special process conditions, thereby obtaining an active lactic acid bacteria fermented tea beverage with balanced nutrition, rich aroma and good stability.

[0031] Under the enzymatic hydrolysis and fermentation process provided by the present invention, the obtained fermented tea beverage has an enhanced flavor, rich tea aroma and fermentation aroma, and the obtained tea beverage retains the health benefits of tea and the efficacy of active lactic acid bacteria, making its flavor and nutrition balanced, providing a new idea for the research and development of tea beverages. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1a The taste sensory evaluation results of the tea beverage M of Example 1 during its shelf life;

[0033] Figure 1b The smell organoleptic evaluation results of the tea beverage M of Example 1 during its shelf life;

[0034] Figure 2 The pH value change of the tea beverage M of Example 1 during the shelf life;

[0035] Figure 3a The sensory evaluation results of the taste of tea beverages C1-C4 of Example 2 and Comparative Examples 1-3 are shown;

[0036] Figure 3b The sensory evaluation results of the odor of tea beverages C1-C4 of Example 2 and Comparative Examples 1-3 are shown;

[0037] Figure 4 The pH value of the tea beverages C1-C4 of Example 2 and Comparative Examples 1-3 during the fermentation process;

[0038] Figure 5a The sensory evaluation results of the taste of the tea beverage C5 of Comparative Example 4 during the enzymatic hydrolysis process;

[0039] Figure 5b The sensory evaluation results of the odor of the tea beverage C5 of Comparative Example 4 during the enzymatic hydrolysis process;

[0040] Figure 6 The pH value change of the tea beverage C5 of Comparative Example 4 during the enzymatic hydrolysis process;

[0041] Figure 7aThe sensory evaluation results of the taste of tea beverages C1 and C5 prepared in Example 2 and Comparative Example 4, respectively;

[0042] Figure 7b The sensory evaluation results of the odor of tea beverages C1 and C5 prepared in Example 2 and Comparative Example 4, respectively;

[0043] Figure 8 The pH values ​​of tea beverages C1 and C5 prepared in Example 2 and Comparative Example 4, respectively. DETAILED DESCRIPTION

[0044] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0045] The lactic acid bacteria used in the examples and comparative examples of the present invention are as follows:

[0046] Lactobacillus paracasei K56 (Inner Mongolia Yili Industrial Group Co., Ltd.), Lactobacillus paracasei ET22 (Inner Mongolia Yili Industrial Group Co., Ltd.), Lactobacillus paracasei 3.02AiBi (Mingfu Health Technology Co., Ltd.), Lactobacillus acidophilus 3.20 (Mingfu Health Technology Co., Ltd.).

[0047] Example 1

[0048] This embodiment provides a flavor-enhanced active lactic acid bacteria fermented tea, and the preparation method thereof is as follows:

[0049] 1. Raw materials

[0050] The raw materials of each 1000g fermented tea beverage include: 3g tea leaves, 0.1g complex enzyme, 0.2g Lactobacillus paracasei K56 bacterial powder, 20g sucrose, 10g glucose, 0.1g yeast powder, and the rest is water.

[0051] 2. Preparation method

[0052] (1) Obtaining tea base material: weighing an appropriate amount of water, soaking a large amount of black tea leaves at 80° C. for 10 min according to a certain proportion, filtering the tea residue through a filter cloth, and cooling to room temperature to obtain a tea base material;

[0053] (2) Adding auxiliary materials: adding sucrose, glucose and yeast powder according to the above proportions;

[0054] (3) Preparation of enzymatic hydrolysate: Add the complex enzyme according to the above ratio, stir evenly, and perform enzymatic hydrolysis at 40°C for 1 h to obtain an enzymatic hydrolysate;

[0055] (4) Preparation and fermentation of bacterial liquid: The enzymatic hydrolyzate was sterilized at 85°C for 30 min and cooled; Lactobacillus paracasei K56 (Inner Mongolia Yili Industrial Group Co., Ltd.) was added to the sterilized and cooled liquid and fermented at 37°C for 24 h to obtain active lactic acid bacteria fermented tea with enhanced flavor, namely, tea beverage M.

[0056] Example 2

[0057] This example provides a flavor-enhanced active lactic acid bacteria fermented tea, the preparation method of which is the same as that of Example 1, except that the amount of tea used in this example is 3 g. The fermented tea obtained in this example is recorded as tea beverage C1.

[0058] Comparative Example 1

[0059] This comparative example provides a lactic acid bacteria fermented tea, and its preparation method is the same as that of Example 2, except that the lactic acid bacteria used in this comparative example is Lactobacillus paracasei ET22 (Inner Mongolia Yili Industrial Group Co., Ltd.). The obtained fermented tea is recorded as tea beverage C2.

[0060] Comparative Example 2

[0061] This comparative example provides a lactic acid bacteria fermented tea, and its preparation method is the same as that of Example 2, except that the lactic acid bacteria used in this comparative example is Lactobacillus paracasei 3.02AiBi (Mingfu Health Technology Co., Ltd.). The obtained fermented tea is recorded as tea beverage C3.

[0062] Comparative Example 3

[0063] This comparative example provides a lactic acid bacteria fermented tea, and its preparation method is the same as that of Example 2, except that the lactic acid bacteria used in this comparative example is Lactobacillus acidophilus 3.20 (Mingfu Health Technology Co., Ltd.). The obtained fermented tea is recorded as tea beverage C4.

[0064] Comparative Example 4

[0065] This comparative example provides a tea beverage C5, and its preparation method is the same as that of Example 2, except that step (4) of Example 2 is omitted in this comparative example, and accordingly, its raw materials do not contain lactic acid bacteria.

[0066] The beneficial effects of the present invention are illustrated below by experimental examples. The methods and reagents used in the experimental examples, unless otherwise specified, are commonly used methods and reagents in the art.

[0067] The following are the detection and analysis methods used in the experimental examples:

[0068] 1. Sensory evaluation:

[0069] A sensory evaluation panel consisting of 6 trained members conducted sensory evaluation on the smell and taste of the fermented tea beverage samples.

[0070] 2. Determination of pH value:

[0071] The pH value of the obtained tea beverage was measured using a pH meter.

[0072] 3. Determination of odor substances:

[0073] Solid phase microextraction-gas chromatography-olfaction-mass spectrometry (SPME-GC-O-MS) was used to qualitatively analyze the main odor substances in fermented tea, and a semi-quantitative method was used to quantitatively analyze the content of the main odor substances. The specific operation is as follows:

[0074] 1. Solid phase microextraction: After shaking the fermented black tea beverage thoroughly, take 5 mL of the sample solution and put it into a clean and odorless headspace bottle (20 mL). At the same time, add 5 μL of 2-methyl-3-heptanone (1 mg / mL) as an internal standard compound to the headspace bottle; balance at a constant temperature of 55°C for 10 minutes, and insert the solid phase microextraction needle into the headspace bottle for adsorption for 40 minutes.

[0075] 2. Gas chromatography-olfaction-mass spectrometry: GC-O-MS is used to identify aroma compounds and aroma substances are separated on the polar chromatographic column DB-WAX. Helium is used as the carrier gas with a constant flow rate of 1.2 mL / min. The extracted volatile substances enter the GC injection port in a non-divided state.

[0076] The specific parameters are as follows:

[0077] GC parameters: The initial temperature of the temperature program was set at 40 °C and maintained for 3 min, then increased to 200 °C at 4 °C / min, maintained for 4 min, and increased to 230 °C at 10 °C / min, maintained for 3 min.

[0078] Sniffing detector parameters: The sniffing port temperature was set to 150°C. To prevent the experimenter's nasal cavity from drying out and affecting judgment, nitrogen was blown through ultrapure water to humidify the air during the test. During the sniffing process, the time when the aroma was smelled, the specific description and the intensity of the smell were recorded.

[0079] Mass spectrometry parameters: ion source temperature was set to 230°C, transfer line temperature was set to 250°C, quadrupole temperature was set to 150°C, electron impact (EI) ion source, electron energy was 70 eV, mass scan range m / z was set to 50-500, and solvent delay was set to 4 min.

[0080] Qualitative analysis: The odor compounds extracted from the obtained tea beverages were qualitatively analyzed by comparative analysis combining mass spectrometry detection (MS), retention index (RI) of standard compounds, and olfactory results (O). Mass spectrometry qualitative analysis compares the mass spectrum of the analyte with the mass spectrometry structure information of the standard compounds in the NIST 2017 library, and the compounds are compared and identified according to the degree of match.

[0081] Quantitative analysis: 2-methyl-3-heptanone (concentration of 1 mg / mL) was used as the internal standard compound to semi-quantitate the odor compounds in the sample using the internal standard method.

[0082] 4. Determination of flavor substances:

[0083] High performance liquid chromatography (HPLC), high performance liquid chromatography-mass spectrometry (HPLC-MS) and ultraviolet spectrophotometry were used to determine the main flavor substances in fermented tea beverages. The specific operations are as follows:

[0084] 1. Determination of phenolic substances:

[0085] HPLC-MS was used to qualitatively and semi-quantitatively analyze the phenolic substances in the fermented black tea beverage of the present invention. After the fermented black tea beverage was fully shaken, it was filtered through a 0.45 μm microporous filter membrane, 990 μL of the sample solution was taken into a 2 mL liquid phase vial, and 10 μL of ethyl gallate (0.1 mg / mL) was added as an internal standard compound.

[0086] The specific parameters are as follows:

[0087] HPLC parameters: Mobile phase A is acetonitrile. Mobile phase B is 0.1% formic acid in water. A Zorbax Eclipse SB-C18 column (4.6 mm × 150 mm, 5 μm) was used. The injection volume was 10 μL. The column temperature was set to 35 °C. The flow rate was set to 1 mL / min. The wavelength was 280 nm. Elution gradient: 10% solvent A, 0 min; 10% solvent A, 10 min; 40% solvent A, 25 min; 40% solvent A, 28 min; 10% solvent A, 30 min; 10% solvent A, 35 min.

[0088] MS parameters: The analytes were detected in negative ion mode, the capillary temperature was set to 300 °C, the capillary voltage was set to 4000 V, the drying gas temperature was 300 °C, the drying gas flow rate was 8 L / min, the nebulizer gas pressure was set to 40 psi, the scanning mode was full scan mode, and the mass scanning range m / z was set to 50-1000.

[0089] Qualitative analysis: Phenols were qualitatively analyzed by comparing the retention time of phenols in the reference and samples and by mass-to-charge ratio in mass spectrometry, with reference to the NIST 2017 library and related literature.

[0090] Quantitative analysis: The phenolic substances in the samples were semi-quantitated using the internal standard method with ethyl gallate (0.1 mg / mL) as the internal standard compound.

[0091] 2. Amino acid determination:

[0092] HPLC was used to determine the amino acid substances in the fermented black tea beverage of the present invention. The amino acids in the sample were analyzed using a Zorbax Eclipse-AAA column, and the sample was subjected to reversed-phase high performance liquid chromatography by pre-column derivatization. The HPLC conditions were: solution A, 0.04 mol / L NaH2PO4 (pH 7.8); solution B, methanol / acetonitrile / H2O (45 / 45 / 10, V / V / V); injection volume 1 μL, temperature 40°C, and ultraviolet detection wavelength 338 nm.

[0093] Qualitative analysis: Qualitative analysis is performed by comparing the retention time of amino acids in the reference and samples.

[0094] Quantitative analysis: The external standard method was used to quantitatively analyze amino acids.

[0095] Experimental Example 1 Determination of flavor components of the tea beverage M of Example 1 during shelf life

[0096] 1. Sensory evaluation results of tea beverages during shelf life

[0097] A sensory evaluation panel consisting of 6 trained members conducted sensory evaluation on the odor and taste of the fermented tea beverage samples obtained by the present invention. A 3-point system was used: 0 for no perception, 0.5-1.5 for weak, 1.5-2.5 for relatively strong, and 3 for strong. The sensory evaluation results of the taste and odor of the tea beverage M during the shelf life were as follows: Figure 1a and Figure 1b shown.

[0098] The taste sensory results showed that the sourness of the tea beverage increased during the shelf life, but the sourness weakened to a certain extent after 30 days of shelf life; the sweetness of the tea beverage weakened during the shelf life, and the bitterness and umami taste did not change significantly. The smell sensory results showed that the tea beverage had no odor during the shelf life, and the overall flavor remained good, with good flavors such as floral and honey aromas stable.

[0099] 2. Changes in pH value of tea beverages during shelf life

[0100] The pH value of the tea beverage M prepared in Example 1 was measured by a pH meter during the shelf life. The results are as follows: Figure 2As shown, it can be seen that within the shelf life of 0 - 20 days, the pH value of the tea beverage shows a downward trend, and it slowly increases within 20 - 30 days. The change in pH value is consistent with the sensory change of sour taste in the taste sensory results.

[0101] 3. Changes in the content of odor substances in the tea beverage during the shelf life

[0102] The main odor substances of the tea beverage M prepared in Example 1 were qualitatively analyzed by solid-phase microextraction - gas chromatography - olfactometry - mass spectrometry (SPME - GC - O - MS), and the content of its main odor substances was quantitatively analyzed by semi - quantitative method. Table 1 shows the types, aroma characteristics and semi - quantitative concentrations of the main odor substances of the tea beverage M prepared in Example 1 during the shelf life.

[0103] Table 1 Types, aroma characteristics and semi - quantitative concentrations of the main odor substances of the tea beverage M during the shelf life

[0104]

[0105]

[0106] After measurement, the content of most odor substances is relatively stable during the shelf life with little change. It can be seen that the tea beverage M in Example 1 of the present invention can maintain a good flavor during the shelf life. Among them, the content of acetic acid increases after fermentation, shows an obvious increase within 0 - 12 days of the shelf life, and the content of acetic acid is relatively stable within the later 12 - 30 days.

[0107] 4. Changes in the content of taste substances in the tea beverage during the shelf life

[0108] The main taste substances of the tea beverage M in Example 1 were determined by high - performance liquid chromatography (HPLC) and high - performance liquid chromatography - mass spectrometry (HPLC - MS). Table 2 shows the types and semi - quantitative or quantitative concentrations of the main taste substances of the tea beverage M in Example 1 during the shelf life.

[0109] Table 2 Types and (semi -) quantitative concentrations of the main taste substances of the tea beverage M in Example 1 during the shelf life

[0110]

[0111]

[0112] After measurement, the total amount of phenolic acid substances in the tea beverage shows a downward trend during the shelf life, but is relatively stable as a whole with no obvious change; the content of flavonol glycosides shows an upward trend; the total amount of catechins increases; the content of lactic acid remains stable in the early stage of the shelf life and shows a certain decline in the later stage; the content of theanine remains stable. Overall, the content of taste substances in the tea beverage during the shelf life is relatively stable with no obvious fluctuation and can maintain a good taste.

[0113] Experimental Example 2 Comparison of flavor components of tea beverages C1-C4 (Example 2, Comparative Examples 1-3)

[0114] 1. Sensory evaluation results of tea beverages C1-C4

[0115] A sensory evaluation panel consisting of 6 trained members conducted sensory evaluation on the odor and taste of the fermented tea beverage samples obtained by the present invention. A 3-point system was used: 0 for no perception, 0.5-1.5 for weak, 1.5-2.5 for relatively strong, and 3 for strong. The sensory evaluation results of the taste and odor of the tea beverages C1-C4 prepared in Example 2 and Comparative Examples 1-3 are shown in Figures 2 and 3. Figure 3a and Figure 3b shown.

[0116] The taste sensory results showed that the tea beverage C1 fermented by Lactobacillus paracasei K56 had moderate sweetness and sourness, almost no bitterness, and good taste. The tea beverages fermented by the other three strains tasted sour and had relatively weak sweetness.

[0117] The results of odor sensory analysis showed that tea beverage C1 had a balanced floral, fruity and honey aroma, especially a relatively strong fruity aroma. The other three tea beverages also had certain floral, fruity and honey aromas, but the honey aroma was heavier. From the overall sensory perspective, tea beverage C1 fermented with Lactobacillus paracasei K56 had a better taste and a balanced aroma.

[0118] 2. Comparison of pH values ​​of tea beverages C1-C4

[0119] The pH values ​​of the tea beverages C1-C4 prepared in Example 2 and Comparative Examples 1-3 respectively during the fermentation process were measured using a pH meter.

[0120] like Figure 4 As shown, the pH values ​​of tea beverages C1-C4 are not much different, among which the pH value of tea beverage C1 is higher, which is consistent with the sensory result of sour taste.

[0121] 3. Comparison of odor substances content in tea beverages C1-C4

[0122] The main odor substances of tea beverages C1-C4 were qualitatively analyzed by solid phase microextraction-gas chromatography-olfaction-mass spectrometry (SPME-GC-O-MS), and the contents of the main odor substances were quantitatively analyzed by semi-quantitative method. Table 3 shows the types, aroma characteristics and semi-quantitative concentrations of the main odor substances of tea beverages C1-C4.

[0123] Table 3 Main odor substances, aroma characteristics and semi-quantitative concentrations of tea beverages C1-C4

[0124]

[0125] It was determined that among the black tea beverages fermented by different strains, the tea beverage C1 fermented by Lactobacillus paracasei K56 had higher contents of α-ionone, β-ionone, damascenone, linalool and other odor substances than the tea beverages fermented by the other three strains, and the acetic acid content was lower, which was consistent with the odor sensory results. Overall, the tea beverage C1 fermented by Lactobacillus paracasei K56 had moderate sweetness and sourness and good taste; the good aromas such as floral, fruity and honey were balanced, and the corresponding odor substances were high in content. Therefore, Lactobacillus paracasei K56 was selected to ferment the tea soup in the subsequent fermentation process.

[0126] Experimental Example 3 Determination of flavor components of tea beverage C5 of Comparative Example 4 during enzymatic hydrolysis

[0127] 1. Sensory evaluation results of tea beverage C5 during enzymatic hydrolysis

[0128] A sensory evaluation panel consisting of 6 trained members conducted a sensory evaluation on the odor and taste of the fermented tea beverage samples obtained by the present invention using a 3-point system: 0 for no perception, 0.5-1.5 for weak, 1.5-2.5 for relatively strong, and 3 for strong. Figure 5a and Figure 5b They are respectively the sensory evaluation results of taste and smell of tea beverage C5 of comparative example 4 during the enzymatic hydrolysis process.

[0129] It was determined that the bitterness of the tea beverage C5 after enzymatic hydrolysis was significantly reduced, and the taste was better; in terms of smell, the resulting tea beverage exhibited a certain floral, fruity and honey aroma, without any unpleasant flavor. The sensory results showed that the aroma of the tea beverage was somewhat weakened after enzymatic hydrolysis.

[0130] 2. Changes in pH value of tea beverage C5 during enzymatic hydrolysis

[0131] The pH value change of the tea beverage C5 of Comparative Example 4 during the enzymatic hydrolysis process was measured using a pH meter. Figure 6 As shown, the obtained tea beverage is weakly acidic, and the pH value shows a downward trend after enzymatic hydrolysis and then tends to be stable, which is consistent with the change of sour taste in the taste sensory results.

[0132] 3. Changes in the content of odor substances in tea beverage C5 during enzymatic hydrolysis

[0133] The main odor substances of the tea beverage C5 of Comparative Example 4 were qualitatively analyzed by solid phase microextraction-gas chromatography-olfaction-mass spectrometry (SPME-GC-O-MS), and the content of the main odor substances was quantitatively analyzed by semi-quantitative method. Table 4 shows the types, aroma characteristics and semi-quantitative concentrations of the main odor substances of the tea beverage C5 of Comparative Example 4 during the enzymatic hydrolysis process.

[0134] Table 4 Main odor substances, aroma characteristics and semi-quantitative concentrations of tea beverage C5 during enzymatic hydrolysis

[0135]

[0136]

[0137] It has been determined that the main odor components in the fermented black tea beverage obtained by the present invention are alcohols, ketones, esters, etc., showing good flavors such as floral, fruity, and honey aromas, and the content of each odor component shows an upward trend after enzymatic hydrolysis.

[0138] 4. Changes in the content of flavor substances in tea beverage C5 during enzymatic hydrolysis

[0139] The main flavor substances of the tea beverage C5 of Comparative Example 4 were determined by high performance liquid chromatography (HPLC) and high performance liquid chromatography-mass spectrometry (HPLC-MS). Table 5 shows the types and semi-quantitative or quantitative concentrations of the main flavor substances of the tea beverage C5 of Comparative Example 4 during the enzymatic hydrolysis process.

[0140] Table 5 Main flavor substances and semi-quantitative or quantitative concentrations of tea beverage C5 during enzymatic hydrolysis

[0141]

[0142]

[0143] It has been determined that the tea beverage C5 of Comparative Example 4 is rich in tea polyphenols, amino acids and other substances. The content of ester catechins (epicatechin gallate, epigallocatechin gallate and epigallocatechin gallate) in the sample after enzymatic hydrolysis is significantly reduced. This type of substance mainly provides astringency to the tea soup. Correspondingly, the gallic acid content is increased, thereby reducing the bitterness of the beverage. The taste sensory evaluation results show that the bitterness of the tea beverage obtained after enzymatic hydrolysis is significantly reduced, thereby improving the taste of the beverage; the content of theanine in the tea beverage is increased after enzymatic hydrolysis, and this substance mainly provides sweetness and freshness to the tea soup.

[0144] Experimental Example 4 Comparison of flavor components of tea beverages C1 and C5 (Example 2, Comparative Example 4)

[0145] 1. Sensory evaluation results of tea beverages C1 and C5

[0146] A sensory evaluation panel consisting of 6 trained members conducted sensory evaluation on the odor and taste of the fermented tea beverage samples obtained in the present invention. A 3-point system was used: 0 for no perception, 0.5-1.5 for weak, 1.5-2.5 for relatively strong, and 3 for strong. The sensory evaluation results of the taste and odor of the tea beverages C1 and C5 prepared in Example 2 and Comparative Example 4, respectively, are shown in Table 1. Figure 7a and Figure 7b shown.

[0147] The taste sensory results showed that the unfermented tea beverage C5 had a slight bitter taste, a stronger sweetness and a less obvious sour taste; while the fermented tea beverage C1 had a significantly stronger sour taste, a weaker sweetness, and no obvious differences in other tastes.

[0148] The odor sensory results showed that the tea beverage C5 had a certain floral, fruity and honey aroma, without any unpleasant flavor; C1 had a stronger sour taste, and its good flavors such as floral, fruity and honey aroma were richer than C5, and its overall aroma was better.

[0149] 2. Comparison of pH values ​​of tea beverages C1 and C5

[0150] The pH values ​​of the tea beverages C1 and C5 prepared in Example 2 and Comparative Example 4, respectively, were measured using a pH meter.

[0151] like Figure 8 As shown, the pH value of tea beverage C1 is higher, which is caused by the fermentation process, which is consistent with the sensory result of sour taste.

[0152] 3. Comparison of odor substances content in tea beverages C1 and C5

[0153] The main odor substances of tea beverages C1 and C5 were qualitatively analyzed by solid phase microextraction-gas chromatography-olfaction-mass spectrometry (SPME-GC-O-MS), and the contents of their main odor substances were quantitatively analyzed by semi-quantitative method. Table 6 shows the types, aroma characteristics and semi-quantitative concentrations of the main odor substances of tea beverages C1-C4.

[0154] Table 6 Main odor substances, aroma characteristics and semi-quantitative concentrations of tea beverages C1 and C5

[0155]

[0156] It was determined that the main odor components in the tea beverages C1 and C5 obtained by the present invention are alcohols, ketones and esters, etc., showing good flavors such as floral, fruity and honey aromas. Compared with tea beverage C5, the acetic acid content in tea beverage C1 is higher, and the content of other odor components is relatively stable, with no significant difference.

[0157] 4. Comparison of flavor substances content in tea beverages C1 and C5

[0158] The main flavor substances in the tea beverages C1 and C5 of Example 2 and Comparative Example 4 were determined by high performance liquid chromatography (HPLC) and high performance liquid chromatography-mass spectrometry (HPLC-MS). Table 7 shows the types and semi-quantitative or quantitative concentrations of the main flavor substances in the tea beverages C1 and C5 of Example 2 and Comparative Example 4.

[0159] Table 7 Main flavor substances and semi-quantitative or quantitative concentrations in tea beverages C1 and C5

[0160]

[0161]

[0162] It has been determined that the tea beverage obtained by the present invention contains rich tea polyphenols and amino acids. Compared with the unfermented tea beverage C5, the enzymatically hydrolyzed and fermented tea beverage C1 has a higher content of tea polyphenols such as lactic acid, phenolic acid, and catechins. Tea polyphenols have antioxidant effects, so tea beverage C1 has better physiological activity.

[0163] In summary, the tea beverage C1 fermented by lactic acid bacteria showed certain advantages in the sensory evaluation results, with a stronger good aroma, a good overall smell, and more functional ingredients such as tea polyphenols. Therefore, it is believed that the fermentation process can improve the flavor quality and functional characteristics of tea beverages.

Claims

1. A flavor-enhanced active lactic acid bacteria fermented tea, wherein the raw materials are include: 0.2%-1% tea leaves, 0.01%-0.05% complex enzyme, 0.01%-0.05% fermentation bacteria, 1%-5% carbon source, 0.01%-0.1% yeast powder, and the balance water; wherein the fermentation bacteria is Lactobacillus paracasei.

2. The flavor-enhanced active lactic acid bacteria fermented tea according to claim 1, in, The fermentation bacteria is Lactobacillus paracasei K56.

3. The flavor-enhanced active lactic acid bacteria fermented tea according to claim 1, in, The carbon source includes at least one of glucose, sucrose and fructose.

4. The flavor-enhanced active lactic acid bacteria fermented tea according to claim 1, in, The tea leaves are black tea.

5. The flavor-enhanced active lactic acid bacteria fermented tea according to claim 1, in, The pH value of active lactic acid bacteria fermented tea is 4.0-4.

1.

6. A method for preparing the flavor-enhanced active lactic acid bacteria fermented tea according to any one of claims 1 to 5, comprising the following steps: Extracting tea leaves with water to obtain tea base; Adding a carbon source and yeast powder to the tea base material, and then adding a composite enzyme for enzymolysis to obtain an enzymolysis solution; The enzymolysis solution is sterilized and cooled, and then fermentation bacteria is added to perform fermentation to obtain the active lactic acid bacteria fermented tea.

7. The method for preparing flavor-enhanced active lactic acid bacteria fermented tea according to claim 6, in, The enzymolysis temperature is 25-60°C, and the enzymolysis time is 1-5h.

8. The method for preparing flavor-enhanced active lactic acid bacteria fermented tea according to claim 6, in, The sterilization temperature is 75-95℃ and the sterilization time is 5-30min.

9. The method for preparing flavor-enhanced active lactic acid bacteria fermented tea according to claim 6, in, The fermentation temperature is 30-45°C and the fermentation time is 18-48h.

10. The method for preparing flavor-enhanced active lactic acid bacteria fermented tea according to claim 6, in, The extraction temperature is 60-90°C, and the extraction time is 5-30min.

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