Preparation method of Liupao tea cream

Abstract

The invention discloses a preparation method of Liupao tea cream. The preparation method comprises the following specific steps: (1) adding nano silicon dioxide powder into a buffer solution to prepare a nano silicon dioxide particle suspension; (2) adding a bio-enzyme solution into the nano silicon dioxide particle suspension, then adding a chitosan solution, and carrying out a constant-temperature oscillation reaction to prepare a silicon dioxide-chitosan loaded bio-enzyme; (3) adding the clean Liupao tea into water, heating and extracting to prepare a Liupao tea extracting solution; (4) adding a silicon dioxide-chitosan loaded bio-enzyme into the Liupao tea extracting solution, and carrying out hydrolysis reaction; (5) filtering the hydrolyzed Liupao tea extracting solution, decocting, concentrating and drying to obtain Liupao tea powder; and (6) adding water into the Liupu tea powder, and carrying out low-temperature heating and paste refining. According to the preparation method of the Liupao tea cream, provided by the invention, the Liupao tea extracting solution is subjected to enzymatic reaction by mainly utilizing the loaded biological enzyme, so that the obtained Liupao tea cream has richer aroma substances and nutrient substances.

Description

Technical Field

[0001] The invention belongs to the field of tea products, and in particular relates to a preparation method of Liubao tea paste. Background Art

[0002] Liubao tea, which originated from Liubao Town, Cangwu County, Wuzhou City, Guangxi Province, has a place in the Chinese tea market with its profound cultural heritage and unique flavor. During the Jiaqing period of the Qing Dynasty (1796-1820 AD), due to its unique betel nut aroma, Liubao tea was honored as one of the twenty-four famous teas in China and was selected as a precious gift to the court (Liao Fangzheng, Li Chaoyu. Research on the historical and cultural inheritance and innovative development of Wuzhou Liubao tea [J]. Tea, 2023, 49(3): 179-182.). Modern research shows that Liubao tea has many health benefits, which mainly come from its unique fermentation process and rich chemical composition. For example, the various polyphenols contained in Liubao tea help lower the level of bad cholesterol in the blood, prevent atherosclerosis, and thus protect the cardiovascular system. The flavonoids contained in Liubao tea can remove free radicals in the human body, reduce oxidative stress, and help delay the aging process. In addition, the nutrients such as catechins, amino acids and soluble tea polysaccharides contained in Liubao tea also have the effects of improving the body's anti-fatigue ability and enhancing immunity (Ma Wanjun, Ma Shicheng, Liu Chunmei, Long Zhirong, Tang Baojun, Lin Zhi, Lv Haipeng. Research progress on the chemical composition and biological activity of Liubao tea [J]. Tea Science, 2020, 40(3): 289-304.).

[0003] At present, the daily drinking method of Liubao tea is still mainly brewed with boiling water, which is not only troublesome to operate but also cannot fully release the nutrients in Liubao tea. With the changes in modern consumption patterns, making Liubao tea into tea paste has become an emerging trend. However, the existing Liubao tea paste on the market is mainly made according to the traditional method: grind Liubao tea into tea powder and then boil it, then boil the filtered tea soup to collect the juice and refine the paste to shape it. The Liubao tea paste made by the traditional method has many impurities and serious loss of flavor substances in the tea paste due to its rough process. The brewed tea soup often has a light musty smell, and the drinking taste and nutritional value are low, so it has not been popular with the public. Therefore, it is meaningful and has broad application prospects to develop a new preparation method of Liubao tea paste. Summary of the invention

[0004] In view of the shortcomings in the existing process for preparing Liubao tea paste, the object of the present invention is to provide a method for preparing Liubao tea paste.

[0005] In order to achieve the above object, the solution of the present invention is:

[0006] A method for preparing Liubao tea paste comprises the following steps:

[0007] (1) adding nano-silica powder into a buffer solution and preparing a nano-silica particle suspension after ultrasonic dispersion;

[0008] (2) adding the bio-enzyme solution to the nano-silica particle suspension obtained in step (1), shaking the resulting mixture on a shaker, adding the chitosan solution and continuing to shake the mixture on a shaker, filtering and collecting the solid, and purifying the solid to obtain a bio-enzyme loaded with silica-chitosan;

[0009] (3) adding clean Liubao tea to water for heating extraction to prepare Liubao tea extract;

[0010] (4) adding the silica-chitosan-loaded biological enzyme prepared in step (2) to the Liubao tea extract prepared in step (3) to carry out a hydrolysis reaction to obtain a hydrolyzed Liubao tea extract;

[0011] (5) filtering the hydrolyzed Liubao tea extract obtained in step (4), adding the extract to a paste making machine, boiling and concentrating the extract, and then drying the extract to obtain Liubao tea powder;

[0012] (6) Add water to the Liubao tea powder prepared in step (5) and heat at low temperature to make the Liubao tea paste.

[0013] Furthermore, the particle size of the nano-silicon dioxide powder described in step (1) is 100 to 200 nm.

[0014] Furthermore, the buffer described in step (1) is Tris-HCl buffer.

[0015] Furthermore, the biological enzyme solution in step (2) is a mixture of one or two of plant proteases or plant hydrolases.

[0016] Furthermore, the shaking reaction conditions in step (2) are: shaking speed of 100 to 300 r / min; reaction temperature of 37° C.; reaction time of 0.5 to 2 h.

[0017] Furthermore, the heating extraction method described in step (3) is ultrasonic heating extraction, the heating extraction temperature is 80-95° C., and the heating extraction time is 0.5-1.5 h.

[0018] Furthermore, the hydrolysis reaction conditions in step (4) are: hydrolysis temperature is 30 to 55° C.; and hydrolysis time is 2 to 6 hours.

[0019] Furthermore, the decoction time in step (5) is 3 to 5 hours, and the decoction temperature is 50 to 65°C.

[0020] Furthermore, the concentration and drying method described in step (5) is spray drying.

[0021] Furthermore, the low-temperature heating refining temperature in step (6) is 50-65°C.

[0022] The main principles of the preparation method of Liubao tea paste provided by the present invention are as follows:

[0023] The preparation method of Liubao tea paste provided by the present invention first uses silicon dioxide powder to react with biological enzymes and modified chitosan solution to prepare biological enzymes loaded with silicon dioxide-chitosan; wherein, the silicon dioxide nanoparticles have unique surface and interface reaction properties, which can not only load a high amount of biological enzymes but also keep the biological enzyme configuration relatively stable; the organic-inorganic nanocomposite carrier prepared by adding modified chitosan can effectively solve the problem of difficulty in separating and recovering the loaded biological enzymes caused by the small particle size of silicon dioxide nanomaterials. Then, the prepared biological enzyme loaded with silicon dioxide-chitosan can be used for enzymatic fermentation treatment of Liubao tea extract, the selected plant hydrolase can decompose the carbohydrates contained in the Liubao tea extract, thereby increasing the content of soluble tea polysaccharides in the extract, and the selected plant protease can hydrolyze the protein in the Liubao tea extract into small molecular amino acids, which can effectively improve the freshness of the tea soup and increase the mellowness of the obtained tea soup. Therefore, the Liubao tea paste prepared by enzymatic fermentation treatment with silica-chitosan loaded bio-enzymes has richer aroma substances and nutrients.

[0024] Compared with the existing preparation method of Liubao tea paste, the invention has the following advantages:

[0025] 1. The preparation method of Liubao tea paste provided by the present invention uses a loaded biological enzyme to perform enzymatic fermentation treatment on the Liubao tea extract during the preparation of the Liubao tea extract. After the treatment, the loaded biological enzyme can be removed by simple filtration, thereby effectively avoiding the influence of the residual biological enzyme on the flavor of the Liubao tea paste.

[0026] 2. The preparation method of Liubao tea paste provided by the present invention dries the Liubao tea concentrate by spray drying during the preparation of the tea paste. Compared with the traditional high-temperature heating drying method, it not only shortens the drying time, but also can further effectively avoid the destruction of nutrients and flavor substances contained in the tea extract.

[0027] 3. The preparation method of Liubao tea paste provided by the present invention also has the advantages of simple process, mild conditions, energy saving and environmental protection, etc., which provides a new idea for the preparation of Liubao tea paste.

[0028] 4. The Liubao tea paste prepared by the preparation method of the Liubao tea paste provided by the present invention has the advantages of small size, light weight and easy to carry; the prepared tea paste can be quickly dissolved in water without waiting for the tea leaves to be soaked, and is very suitable for the quick drinking needs in fast-paced life. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a picture of the finished product of Liubao tea paste provided by the present invention.

[0030] Figure 2 This is a diagram of the Liubao tea paste provided by the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the embodiments. It should also be understood that the following embodiments are only used to further illustrate the present invention and cannot be construed as limiting the scope of protection of the present invention. The specific quality, reaction time and temperature, process parameters, etc. in the examples are only examples within the appropriate ranges. Some non-essential improvements and adjustments made by those skilled in the art according to the above content of the present invention all belong to the scope of protection of the present invention.

[0032] All reagents used were commercial reagents unless otherwise specified and were not further purified before use.

[0033] The particle size of the nano-silicon dioxide powder used in the examples of the present invention is 100-200 nm and needs to be dried at 120° C. for more than 12 hours before use.

[0034] The chitosan used in the examples of the present invention needs to be modified before use. The specific steps are as follows: 5 g of chitosan is added to 100 mL of 2% acetic acid solution. After fully dissolved, the obtained chitosan solution is added dropwise to 20 mL of 1 mol / L sodium hydroxide solution. The obtained mixture is stirred for reaction for 30 minutes and then filtered to collect the obtained white precipitate. The white precipitate is washed with distilled water until neutral and then placed in a vacuum drying oven at 30°C for 12 hours. The dried solid is placed in 15 mL of 50 mmol / L citric acid solution and soaked for 12 hours, then vacuum filtered, and the obtained solid is dried to obtain citric acid pretreated chitosan. The obtained chitosan carrier pretreated with citric acid was added to 5 mL of 1.25% glutaraldehyde solution. The obtained mixture was oscillated in a water bath at room temperature for 10 min and then allowed to stand for 5 h. It was then centrifuged and the obtained solid was washed three times with 5 mL of 50 mmol / L citric acid solution and placed in a vacuum drying oven and dried at 35°C to obtain a glutaraldehyde-modified chitosan carrier, totaling 4.2 g.

[0035] Embodiment 1:

[0036] The preparation steps of Liubao tea paste are as follows:

[0037] (1) 6 g of nano-silica powder was added to 10 mL of Tris-HCl buffer (pH = 8.0) and ultrasonically dispersed for 30 min to obtain a nano-silica particle suspension;

[0038] (2) Add 15 mL of a 20 mg / mL papain solution to the nano-silica particle suspension prepared in step (1), shake the resulting mixture on a shaker at a speed of 180 r / min and a temperature of 37° C. for 35 min, then add 1.5 mL of a 0.5% glutaraldehyde-modified chitosan carrier solution, then continue to shake on the shaker for 45 min while keeping the temperature and speed unchanged, centrifuge, and wash the resulting solid three times with 5 ml of distilled water to obtain silica-glutaraldehyde-modified chitosan-loaded papain, a total of 5.8 g, which is stored in a refrigerator at 4° C. for later use;

[0039] (3) 1 kg of clean Liubao tea was added to an extraction tank, and then 5 L of water was added. The extraction tank was placed in an ultrasonic generator with a constant temperature function, and the extraction time was 45 min under the conditions of ultrasonic power of 800 W and temperature of 60° C. After filtering, Liubao tea extract was obtained;

[0040] (4) adding 1.5 g of papain loaded with silica-chitosan-modified chitosan loaded with glutaraldehyde prepared in step (2) to the Liubao tea extract prepared in step (3), and hydrolyzing the mixture at 50° C. for 3 h, filtering out insoluble matter, and obtaining a hydrolyzed Liubao tea extract;

[0041] (5) adding the hydrolyzed Liubao tea extract obtained in step (4) into a paste making machine and boiling it at 60° C. and a vacuum degree of 3 kPa for 50 min to obtain a Liubao tea concentrate; then passing the Liubao tea concentrate into a spray dryer for spray drying, setting the inlet air temperature to 120° C. and the outlet air temperature to 60° C., and the obtained powder is Liubao tea powder;

[0042] (6) Add the Liubao tea powder prepared in step (5) into a ceramic pot and then add about 20 g of water, heat at 55° C. and stir to refine the paste until the paste is difficult to stir and can be drawn into a thread without breaking. After cooling to room temperature, the Liubao tea paste can be obtained. Figure 1 shown.

[0043] The prepared Liubao tea paste was characterized for the content of tea polyphenols, total flavonoids, soluble polysaccharides and free amino acids and other physicochemical properties. Among them, the free amino acid content was tested by preparing the test solution according to Appendix A.4.1 of QBT4067-2010 Food Industry Instant Tea, and then tested with reference to GB8314-2002 Tea Total Free Amino Acid Determination; the tea polyphenol content was determined by referring to the detection method of tea polyphenols in instant tea in Appendix A of QBT4067-2010 Food Industry Instant Tea; the total flavonoids were detected by HPLC-MS; the soluble total sugar was determined by anthrone colorimetry; the characterization results are shown in Table 1.

[0044] The aroma components of the prepared Liubao tea paste were detected. The specific detection method was carried out according to the reference (Ma Shicheng, Wang Mengqi, Liu Chunmei, Long Zhirong, Ma Wanjun, Zhu Yin, Lin Zhi, Lv Haipeng. Analysis of key aroma components in the volatile components of Liubao tea [J]. Food Science, 2020, 41(20): 191-197.), and the characterization results are shown in Tables 2 and 3.

[0045] Embodiment 2:

[0046] The preparation of Liubao tea paste is based on Example 1, except that the papain in step (2) is replaced with ficin, and the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 2.

[0047] Embodiment 3:

[0048] The preparation of Liubao tea paste is based on Example 1, except that the papain in step (2) is replaced with neutral protease, and the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 2.

[0049] Embodiment 4:

[0050] The preparation of Liubao tea paste is based on Example 1, except that the papain in step (2) is replaced with bromelain, and the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 2.

[0051] Embodiment 5:

[0052] The preparation of Liubao tea paste refers to Example 1, except that the papain in step (2) is replaced with pectinase, and the remaining steps are the same as Example 1; the characterization of the prepared Liubao tea paste is the same as Example 1; the characterization results are shown in Tables 1 and 2.

[0053] Embodiment 6:

[0054] The preparation of Liubao tea paste is based on Example 1, except that the papain in step (2) is replaced with galactosidase, and the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 2.

[0055] Embodiment 7:

[0056] The preparation of Liubao tea paste is based on Example 1, except that the papain in step (2) is replaced with xylanase, and the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 2.

[0057] Embodiment 8:

[0058] The preparation of Liubao tea paste is based on Example 1, except that the papain in step (2) is replaced with cellulase, and the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 2.

[0059] Embodiment 9:

[0060] The preparation of Liubao tea paste is based on Example 1, except that the hydrolysis temperature in step (4) is increased to 55°C and the hydrolysis time is changed to 2h; the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 3.

[0061] Embodiment 10:

[0062] The preparation of Liubao tea paste refers to Example 1, except that the hydrolysis temperature in step (4) is reduced to 45°C and the hydrolysis time is changed to 4h; the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 3.

[0063] Embodiment 11:

[0064] The preparation of Liubao tea paste refers to Example 1, except that the hydrolysis temperature in step (4) is reduced to 40°C and the hydrolysis time is changed to 5 hours; the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 3.

[0065] Embodiment 12:

[0066] The preparation of Liubao tea paste refers to Example 1, except that the inlet air temperature of the spray drying in step (5) is changed to 150°C and the outlet air temperature is changed to 90°C; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 3.

[0067] Table 1 Characterization of Liubao tea paste ingredients

[0068] Amino Acid Content Tea polyphenols content Total flavonoids content Soluble sugar content Example 1 9.4％ 32.1％ 8.4％ 4.9％ Example 2 9.1％ 31.9％ 8.3％ 4.8％ Example 3 8.7％ 32.0％ 8.3％ 4.9％ Example 4 8.9％ 32.2％ 8.8％ 4.6％ Example 5 8.1％ 32.5％ 8.2％ 5.4％ Example 6 8.0％ 32.2％ 8.3％ 5.2％ Example 7 8.3％ 32.7％ 8.5％ 6.1％ Example 8 8.2％ 32.8％ 8.4％ 5.7％ Example 9 8.7％ 31.9％ 8.3％ 4.7％ Example 10 9.3％ 32.4％ 8.4％ 5.1％ Embodiment 11 9.7％ 32.9％ 8.5％ 5.2％ Example 12 9.2％ 32.0％ 8.3％ 4.8％ Embodiment 13 10.3％ 33.2％ 8.6％ 6.3％ Comparative Example 1 8.8％ 31.8％ 8.4％ 4.5％ Comparative Example 2 8.5％ 31.3％ 8.2％ 4.2％ Comparative Example 3 10.8％ 33.9％ 8.7％ 4.9％ Comparative Example 4 7.7％ 30.9％ 7.8％ 3.4％

[0069] Embodiment 13:

[0070] The preparation of Liubao tea paste is based on Example 1, except that the papain in step (2) is replaced by a mixture of papain and xylanase, both of which are used in an amount of 15 ml; the hydrolysis temperature in step (4) is reduced to 40°C and the hydrolysis time is changed to 5 hours; the remaining steps are the same as in Example 1; the characterization of the prepared Liubao tea paste is the same as in Example 1; the characterization results are shown in Tables 1 and 3.

[0071] Comparative Example 1

[0072] The preparation of Liubao tea paste refers to Example 1, except that the glutaraldehyde-modified chitosan carrier solution in step (2) is replaced with a chitosan carrier solution, and the remaining steps are the same as Example 1; the characterization of the prepared Liubao tea paste is the same as Example 1; the characterization results are shown in Tables 1 and 3.

[0073] Comparative Example 2

[0074] The preparation of Liubao tea paste refers to Example 1, except that the amount of glutaraldehyde-modified chitosan carrier solution in step (2) is changed to 0, and the remaining steps are the same as Example 1; the characterization of the prepared Liubao tea paste is the same as Example 1; the characterization results are shown in Tables 1 and 3.

[0075] Comparative Example 3

[0076] The preparation steps of Liubao tea paste are as follows:

[0077] (1) Add 1 kg of clean Liubao tea into an extraction tank, then add 5 L of water, place the extraction tank in an ultrasonic generator with a constant temperature function, extract for 45 min at 60° C. and an ultrasonic power of 800 W, and obtain a Liubao tea extract after filtering;

[0078] (2) adding 15 mL of a 20 mg / mL papain solution to the Liubao tea extract obtained in step (1), hydrolyzing the resulting solution at 50° C. for 3 h, and then filtering out insoluble matter to obtain a hydrolyzed Liubao tea extract;

[0079] (3) adding the hydrolyzed Liubao tea extract obtained in step (2) into a paste making machine and boiling it at 60° C. and a vacuum degree of 3 kPa for 50 min to obtain a Liubao tea concentrate; then passing the Liubao tea concentrate into a spray dryer for spray drying, setting the inlet air temperature to 120° C. and the outlet air temperature to 60° C., and the obtained powder is Liubao tea powder;

[0080] (4) Add the Liubao tea powder prepared in step (3) into a ceramic pot and then add about 20 g of water, heat at a low temperature of 55° C. and stir to refine the paste until the paste is difficult to stir and can be drawn into threads without breaking. After cooling to room temperature, the Liubao tea paste can be obtained. The characterization of the prepared Liubao tea paste is the same as that in Example 1. The characterization results are shown in Tables 1 and 3.

[0081] Comparative Example 4

[0082] The preparation of Liubao tea paste refers to comparative example 3, except that step (2) is omitted, and the remaining steps are the same as those in Example 1; the characterization of the prepared Liubao tea paste is the same as that in Example 1; the characterization results are shown in Tables 1 and 3.

[0083] Table 2 Detection table of aroma substances in Liubao tea paste

[0084]

[0085] *Indicates that the substance was detected in Liubao tea paste; ND indicates that the substance was not detected.

[0086] Table 3 Liubao tea paste aroma substance detection table 2

[0087]

[0088] *Indicates that the substance was detected in Liubao tea paste; ND indicates that the substance was not detected.

[0089] In addition, we also conducted a sensory evaluation after brewing the prepared Liubao tea paste. The brewing steps are as follows: dissolve 2g of tea paste in 500ml of boiling water and let it stand for a while. Figure 2 The specific method of sensory evaluation is as follows: the tea soup color, aroma and taste are scored on a 100-point scale, with each part accounting for 30 points, 30 points and 40 points respectively. Professional tea tasters conduct sensory evaluation and give corresponding comments based on the quality characteristics. The results are shown in Table 4.

[0090] Table 4 Sensory evaluation results of Liubao tea paste

[0091]

Claims

1. A method for preparing Liubao tea paste, characterized in that: The steps include: (1) adding nano-silica powder into a buffer solution and preparing a nano-silica particle suspension after ultrasonic dispersion; (2) adding the bio-enzyme solution to the nano-silica particle suspension obtained in step (1), shaking the resulting mixture on a shaker, adding the chitosan solution and continuing to shake the mixture on a shaker, filtering and collecting the solid, and purifying the solid to obtain a bio-enzyme loaded with silica-chitosan; (3) adding clean Liubao tea to water for heating extraction to prepare Liubao tea extract; (4) adding the silica-chitosan-loaded biological enzyme prepared in step (2) to the Liubao tea extract prepared in step (3) to carry out a hydrolysis reaction to obtain a hydrolyzed Liubao tea extract; (5) filtering the hydrolyzed Liubao tea extract obtained in step (4), adding the extract to a paste making machine, boiling and concentrating the extract, and then drying the extract to obtain Liubao tea powder; (6) Add water to the Liubao tea powder prepared in step (5) and heat at low temperature to make the Liubao tea paste.

2. The method for preparing Liubao tea paste according to claim 1, characterized in that: The particle size of the nano silicon dioxide powder described in step (1) is 100 to 200 nm.

3. The method for preparing Liubao tea cream according to claim 1, characterized in that: The buffer described in step (1) is Tris-HCl buffer.

4. The method for preparing Liubao tea paste according to claim 1, characterized in that: The biological enzyme solution in step (2) is a mixture of one or two of plant proteases or plant hydrolases.

5. The method for preparing Liubao tea cream according to claim 1, characterized in that: The shaking reaction conditions described in step (2) are: shaking speed of 100-300 r / min; reaction temperature of 37° C.; reaction time of 0.5-2 h.

6. The method for preparing Liubao tea cream according to claim 1, characterized in that: The heating extraction method described in step (3) is ultrasonic heating extraction, the heating extraction temperature is 80-95° C., and the heating extraction time is 0.5-1.5 h.

7. The method for preparing Liubao tea cream according to claim 1, characterized in that: The hydrolysis reaction conditions described in step (4) are: hydrolysis temperature is 30-55° C.; and hydrolysis time is 2-6 h.

8. The method for preparing Liubao tea cream according to claim 1, characterized in that: The decoction time in step (5) is 3 to 5 hours, and the decoction temperature is 50 to 65°C.

9. The method for preparing Liubao tea cream according to claim 1, characterized in that: The drying method described in step (5) is spray drying.

10. The method for preparing Liubao tea paste according to claim 1, characterized in that: The low-temperature heating refining temperature described in step (6) is 50-65°C.

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