Method for preparing radius camellia cream by utilizing variable-voltage magnetic induction electric field-enzyme coupling method

Abstract

The invention relates to the field of preparation of tea extractum, in particular to a method for preparing camellia cream by utilizing a variable-voltage magnetic induction electric field-enzyme coupling method. The method mainly comprises the following steps: under the protection of inert gases such as nitrogen, performing coupling extraction on a mixture of camellia japonica powder and water and hydrolase for a certain time under the magnetic induction of lower voltage, then increasing the voltage of the magnetic induction, performing extraction for a certain time under the magnetic induction of higher voltage, releasing nitrogen, performing centrifugation, and performing reduced-pressure low-temperature rotary evaporation on supernate to obtain the camellia japonica powder. And drying to obtain the Japanese camellia cream. The method disclosed by the invention is high in extraction rate, and the flavor of the obtained extract is closer to the aroma and taste of freshly processed camellia japonica.

Description

Technical Field

[0001] The invention relates to the field of tea extract preparation, and in particular to a method for preparing Jingshan camellia extract by utilizing a transformer-type magnetic induction electric field-enzyme coupling method. Background Art

[0002] The characteristic aroma of tea extract is an important quality factor, and tea extract is an important form of tea extract.

[0003] At present, the main preparation methods of tea extract are organic solvent extraction, supercritical carbon dioxide extraction, boiling water extraction, etc., each of which has its own advantages and disadvantages. For example, boiling water extraction has a high temperature and a long extraction time, and is prone to oxidation, condensation, polymerization and other reactions, resulting in a large difference between the aroma and the actual aroma of tea leaves; organic solvent extraction may leave residual organic solvents, and organic solvent extraction also needs to be carried out at a higher temperature, and is prone to oxidation, condensation, polymerization and other reactions at high temperatures, resulting in a difference between the aroma and the actual aroma of tea leaves. In addition, when removing the organic solvent, it will cause the loss of volatile components and distort the aroma; supercritical carbon dioxide extraction is a better method for essential oil extraction developed in the past 10 to 20 years, with advantages such as low extraction temperature, high extraction rate, and no solvent residue, but it also has disadvantages such as the need for high-pressure equipment, high cost, and incomplete extraction components, which distorts the aroma.

[0004] The tea leaves of Jianshan are delicate and fine in appearance, emerald green in color, with a refreshing aroma, bright green tea soup and a tender and fresh taste.

[0005] There have been reports on the application of magnetic induction electric field technology in the extraction of bioactive substances, such as polysaccharides and pectin, but there is still a lack of application in the preparation of Jingshan camellia paste. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing Jingshan camellia paste by using a transformer-type magnetic induction electric field-enzyme coupling method, thereby improving the flavor, taste and extraction yield of the Jingshan camellia paste.

[0007] In order to solve the above technical problems, the present invention provides a method for preparing Jingshan Camellia Extract by using a variable voltage magnetic induction electric field-enzyme coupling method, comprising the following steps:

[0008] 1) Adjust the pH of pure water (deionized water) to 5.0-6.5 to obtain acid-adjusted pure water;

[0009] Then, according to the material-liquid ratio of 1g:20-30ml (preferably 1g:25ml), weigh the camellia sinensis powder and add it to the above-mentioned acid-adjusted pure water to allow the camellia sinensis powder to absorb water and swell for 0.5-1.5h (preferably 1h);

[0010] 2) Add chitosan-immobilized hydrolase to the liquid obtained in step 1) at a dosage ratio of 100-1500U (preferably 1000-1500U) of hydrolase per 1g of camellia powder, mix well and load into a magnetic induction device;

[0011] 3) First, evacuate the magnetic induction device, and then fill it with inert gas to normal pressure;

[0012] 4) Adjust the magnetic induction voltage to 400-600V and extract for 35-45min under stirring;

[0013] 5) Adjust the magnetic induction voltage to 900-1100V and extract for 15-25min under stirring;

[0014] 6) Turn off the magnetic induction, release the inert gas, centrifuge the liquid obtained in step 5), and concentrate the obtained supernatant by vacuum rotary evaporation to a paste to obtain Jingshan Camellia Paste.

[0015] As an improvement of the method for preparing camellia paste using a variable voltage magnetic induction electric field-enzyme coupling method of the present invention, in the step 2), the hydrolase is at least any one of the following: β-glucosidase, α-glucosidase, β-galactosidase, cellulase.

[0016] As a further improvement of the method for preparing Jingshan Camellia Extract by using the variable voltage magnetic induction electric field-enzyme coupling method of the present invention, the step 6):

[0017] Centrifugation is 4500-5500 rpm for 8-12 min (preferably 5000 rpm for 10 min);

[0018] The evaporation temperature is 45-55°C;

[0019] The solid content of Jingshan Camellia Extract is 60-70% (weight %).

[0020] As a further improvement of the method for preparing Jingshan camellia paste by utilizing the transformer-type magnetic induction electric field-enzyme coupling method of the present invention: the Jingshan camellia is crushed and passed through a 60±10 mesh sieve to obtain the Jingshan camellia powder.

[0021] Jianshan tea is generally selected within 2 months from the date of processing.

[0022] As a further improvement of the method for preparing camellia paste using a variable voltage magnetic induction electric field-enzyme coupling method of the present invention, the inert gas in step 3) is nitrogen or argon.

[0023] As a further improvement of the method for preparing Jingshan Camellia Extract by using the variable voltage magnetic induction electric field-enzyme coupling method of the present invention:

[0024] The step 4) is: adjusting the magnetic induction voltage to 500V and extracting for 40 minutes;

[0025] The step 5) is: adjusting the magnetic induction voltage to 1000 V and extracting for 20 minutes.

[0026] The invention mainly adopts the following steps: extracting a mixture of Jingshan camellia powder and water for a certain period of time by coupling magnetic induction with hydrolase at a relatively low voltage under the protection condition of inert gas such as nitrogen, then increasing the voltage of magnetic induction, extracting for a certain period of time under magnetic induction at a relatively high voltage, releasing nitrogen, centrifuging, and then reducing the pressure and low-temperature rotary evaporation of the supernatant to obtain Jingshan camellia paste.

[0027] In the present invention:

[0028] Hydrolases are used to hydrolyze flavor precursors in the glycosidic bond state in tea, thereby releasing the flavor substances, which is beneficial to improving the flavor of the product; the use of chitosan-immobilized hydrolases can enhance the hydrolysis effect.

[0029] The extraction is carried out under the protection of inert gas; the inert gas protects the easily oxidizable components in the tea to prevent them from being oxidized due to the increase in temperature under the subsequent magnetic induction electric field, thus avoiding the oxidation of the components and causing changes in flavor.

[0030] The present invention adjusts the first magnetic induction voltage to 400-600V (preferably 500V) and the second magnetic induction voltage to 900-1100V (preferably 1000V), thereby ensuring that the hydrolase works at a suitable temperature and that the extraction efficiency is ensured.

[0031] Step 6 of the present invention is to concentrate the mixture into a paste by vacuum rotary evaporation at 45-55° C. Concentrating the mixture under relatively low temperature and vacuum conditions can effectively protect the oxidative components, thereby avoiding significant changes in flavor.

[0032] The present invention has the following technical advantages:

[0033] The method adopts a variable voltage magnetic induction electric field, which is coupled with a hydrolase at a lower magnetic voltage in the first stage to improve the flavor of the Jingshan tea paste. The higher magnetic voltage in the subsequent stage can improve the extraction rate of the target substance of the Jingshan tea. All operation processes are carried out at normal pressure to avoid excessive requirements on equipment. Compared with boiling water extraction, it is carried out at a lower temperature and is protected by an inert gas, which can avoid the destruction of easily oxidized components in the flavor substances and cause flavor changes. The β-glucosidase, α-glucosidase, β-galactosidase, cellulase, etc. used can release non-volatile flavor precursors in a glycosidic bond state, thereby enhancing the final aroma of the Jingshan tea paste.

[0034] In summary, the present invention adopts a method for preparing Jingshan camellia paste by utilizing a variable voltage magnetic induction electric field-enzyme coupling method. Compared with traditional boiling water extraction method, organic solvent extraction method, supercritical carbon dioxide extraction method, etc., the present invention does not use organic solvents, extracts at a lower temperature, is carried out under normal pressure conditions, and has a high extraction rate. The flavor of the obtained extract is closer to the aroma and taste of freshly processed Jingshan tea. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0036] 1. Jingshan tea is purchased from the market. Freshly processed Jingshan tea (within 2 months from the date of processing) is crushed and passed through a 60-mesh sieve to obtain Jingshan tea powder for later use.

[0037] 2. Preparation of chitosan-immobilized hydrolase according to conventional techniques, for example, can be specifically as follows:

[0038] Chitosan was added to a 1% (volume %) acetic acid aqueous solution at a solid-liquid ratio of 1.5 g / 100 ml and dissolved in a 40° C. water bath to form a colloidal solution, which was named chitosan solution;

[0039] Take 100 mL of hydrolase solution, adjust the pH to 6.0, balance in a 40°C water bath for 20 minutes, add 100 mL of chitosan solution while stirring, let stand for 2.5 hours, filter out the precipitate, make it into granules (particle size is about 1-2 mm), blow dry with cold air, and then place it in 100 ml of 0.25% (volume %) glutaraldehyde aqueous solution and let stand for 8 hours. After filtering, rinse with water, and dry at room temperature to obtain immobilized hydrolase (about 500-1500 U / g).

[0040] Its activity is measured according to a conventional hydrolase activity test method, and the amount of enzyme required to release 1 μg of glucose or galactose or cellobiose per gram of immobilized hydrolase per hour is defined as one enzyme activity unit (U / g).

[0041] The hydrolase may be any one of the following: β-glucosidase, α-glucosidase, β-galactosidase, and cellulase.

[0042] The Jingshan tea powder used in all the following cases is from the same batch.

[0043] Example 1: A method for preparing Jingshan Camellia Extract by using a variable voltage magnetic induction electric field-enzyme coupling method, comprising the following steps:

[0044] 1) Weigh 100g of Camellia sinensis powder, add it to 2500mL of pure water (deionized water) adjusted to pH 5.0-6.5 with saturated aqueous solution of citric acid, and mix well, allowing the powder to absorb water and swell for 1h;

[0045] 2) Add chitosan-immobilized β-glucosidase to the liquid obtained in step 1) according to the dosage ratio of 1000U β-glucosidase per 1g of camellia powder, mix well and load into the magnetic induction device;

[0046] 3) First, evacuate the magnetic induction device, and then fill it with inert gas nitrogen to normal pressure;

[0047] 4) Adjust the magnetic induction voltage to 500V and extract for 40 minutes under stirring; at this time, the material temperature is about 50°C;

[0048] 5) Adjust the magnetic induction voltage to 1000V and extract for 20 minutes; at this time, the material temperature is about 85°C;

[0049] 6) Turn off the magnetic induction, release the nitrogen, centrifuge the obtained liquid (5000rpm, 10min), and concentrate the supernatant by vacuum rotary evaporation at 50°C to remove most of the water until it becomes a paste, to obtain 6.8g of Jingshan camellia paste sample #1; then the solid content in the tea paste was determined to be 62.6%, so the extraction rate was 4.26%.

[0050] Extraction rate = 100 * solid content in tea paste (%) * tea paste sample weight (g) / tea powder weight (g)

[0051] Comparative Example 1: The conventional boiling water extraction method was used to prepare the camellia paste, and the main steps were:

[0052] Weigh 100g of Jingshan tea powder, mix it with 2500mL of pure water, let the tea powder absorb water and swell for 1h, then place it in an extraction tank (equipped with corresponding heating device and condensing water device), heat it to boiling state and reflux extract for 4h, stop extraction, cool it to room temperature, centrifuge the liquid (5000rpm, 10min), and concentrate the supernatant by 50℃ vacuum rotary evaporation to paste, and obtain 5.9g of Jingshan tea paste sample #2. The solid content in the tea paste was determined to be 63.4%, so the extraction rate was 3.74%.

[0053] Experiment 1:

[0054] In order to evaluate the aroma and taste of the Jingshan tea paste obtained by the two methods of Example 1 and Comparative Example 1, the evaluation was carried out according to GB / T23776-2018 "Tea Sensory Evaluation Method". Since the extract does not have the appearance and leaf bottom indicators, the proportion of each indicator is adjusted to 50% for aroma, 40% for flavor, and 10% for soup color. The score of the original tea sample is used as the comparison object, with a 10-point system.

[0055] Weigh 2.00g of the original tea powder sample, place it in a 150mL tea evaluation cup, fill it with boiling water, cover it, and brew it for 5 minutes. Then drain the tea soup into the tea evaluation bowl and evaluate its aroma and taste.

[0056] At the same time, take 0.2g of camellia paste sample and place it in a 150mL tea evaluation cup, fill it with boiling water, and stir it with a glass rod to make it completely dissolved. After 1min to 2min, evaluate it and compare it with the original tea.

[0057] Nine tasters who had undergone training and preliminary screening and had strong tea flavor recognition capabilities were selected to score the aroma, tea soup color, and taste (flavor) characteristics of the Jingshan tea paste and original tea samples. The results (average scores) are shown in Table 1.

[0058] From the extraction rate point of view, the yield of the Jingshan camellia paste obtained by the preparation method of the present invention is higher than that of the Jingshan camellia paste obtained by the boiling water bath preparation method as a control.

[0059] From the perspective of sensory evaluation, the comprehensive score of the Jingshan tea paste prepared by the present invention has no significant difference with the original tea in terms of aroma, taste, soup color and overall sensory evaluation, but the overall evaluation, aroma and taste are higher than the Jingshan tea paste sample prepared by boiling water bath as the control, while there is no significant difference in soup color among the three samples. In terms of aroma and taste, the tea paste #1 prepared by the present invention method is significantly better than the tea paste #2 prepared by the control method, but has no significant difference with the original tea, which is largely related to the high extraction rate, nitrogen protection and glycosidase treatment of the present invention method.

[0060] Table 1. Comparison of yield and sensory evaluation of several Jingshan tea extracts

[0061]

[0062] Notes: 1. Tea paste #1 is the Jingshan tea paste sample prepared by the method of the present invention, and Tea paste #2 is the Jingshan tea paste sample prepared by the boiling water bath method; 2. Different lowercase letters represent significant differences in the sensory evaluation of the same column (p<0.05).

[0063] Embodiment 2:

[0064] Change step 2) of Example 1 into:

[0065] According to the dosage ratio of 1000U β-glucosidase + 500U β-galactosidase per 1g of Camellia sinensis powder, chitosan-immobilized β-glucosidase and chitosan-immobilized β-galactosidase were added to the liquid in step 1), mixed and loaded into the magnetic induction device;

[0066] The rest is the same as Example 1.

[0067] 6.5 g of Jingshan Camellia Extract Sample #3 was obtained. The solid content was determined to be 66%, and the extraction rate was calculated to be 4.29% (as shown in Table 2).

[0068] Comparative Example 2: With respect to Example 1, the following changes were made:

[0069] The chitosan-immobilized β-glucosidase in step 2) was eliminated; the rest was the same as in Example 1.

[0070] Comparative Example 3-1, relative to Example 1, made the following changes:

[0071] Steps 4) and 5) were unified as follows: the magnetic induction voltage was adjusted to 1000 V and the extraction was performed for 60 min;

[0072] The rest is the same as Example 1.

[0073] Comparative Example 3-2, relative to Example 1, made the following changes:

[0074] Step 4) and step 5) are unified as follows: the magnetic induction voltage is adjusted to 500 V, and the extraction is performed for 60 min; the rest is the same as in Example 1.

[0075] Comparative Example 3-3, relative to Example 1, made the following changes:

[0076] The “500 V, extraction 40 min” in step 4) was changed to “700 V, extraction 30 min”; the rest was the same as in Example 1.

[0077] Comparative Example 3-4, relative to Example 1, made the following changes:

[0078] The “500 V, extraction 40 min” in step 4) was changed to “300 V, extraction 70 min”; the rest was the same as in Example 1.

[0079] Comparative Examples 3-5, relative to Example 1, make the following changes:

[0080] The “1000 V, extraction for 20 min” in step 5) was changed to “700 V, extraction for 30 min”; the rest was the same as in Example 1.

[0081] Comparative Examples 3-6, relative to Example 1, make the following changes:

[0082] The “1000 V, extraction for 20 min” in step 5) was changed to “1500 V, extraction for 15 min”; the rest was the same as in Example 1.

[0083] Comparative Example 4: The step 3) of "evacuating the air and then filling the air with inert nitrogen to normal pressure" is cancelled, that is, the step 4) is directly performed after the step 2) is completed, that is, magnetic induction is performed in an air atmosphere. The rest is the same as in Example 1.

[0084] The sensory evaluation method was the same as in Experiment 1. The results are shown in Table 2.

[0085] Table 2. Comparison of yield and sensory evaluation of Jingshan tea extract

[0086]

[0087] According to Table 2, the extraction using a continuous magnetic induction voltage of 1000V (Comparative Example 3-1) has a higher extraction rate than Example 2, probably because the continuous high magnetic induction voltage keeps the material temperature high and causes greater cell damage, but the aroma and taste scores are significantly lower than Example 1.

[0088] Experiment 2: The Jingshan tea cream obtained in Example 1, Example 2 and Comparative Example 1 was tested by headspace solid phase microextraction-gas chromatography-mass spectrometry to determine the volatile aroma components. The contents of several important aroma contributing components of the Jingshan tea cream were compared.

[0089] Table 3. Comparison of the contents of several important aroma-contributing components in the prepared Jingshan tea paste

[0090]

[0091] Geraniol, methyl dihydrojasmonate, cis-jasmone, linalool, dimethyl sulfide, N-ethylpyrrole, 3-ethyl-2,5-dimethylpyrazine, etc. are characteristic aroma components of Jianshan tea. The contents of 22 characteristic aroma components in the volatile components of the Jianshan tea paste (Examples 1 and 3) prepared by the present invention and the Jianshan tea paste (Comparative Example 1) prepared by the boiling water bath method are compared, and the results are shown in Table 3. The total amount of these 22 characteristic aroma components in the Jianshan tea paste prepared by the present invention is significantly higher than that of the Jianshan tea paste prepared by the boiling water bath method, and the content of key aroma components such as geraniol, linalool, indole, cis-jasmone, dimethyl sulfide, N-ethylpyrrole, 3-ethyl-2,5-dimethylpyrazine is also higher than that of the tea paste prepared by the boiling water bath. These differences may be one of the important reasons for the significant difference in the sensory evaluation of aroma.

[0092] Experiment 3: The contents of catechins, tea polyphenols and caffeine in the Jingshan tea extract obtained in Example 1, Example 2 and Comparative Example 1 were determined according to GB / T 8318-2018 "Test Method for Tea Polyphenols and Catechins in Tea". The total amount of free amino acids was determined according to GB / T8314-2013 "Determination of the Total Amount of Free Amino Acids in Tea". The results are shown in Table 4.

[0093] Table 4. Comparison of the contents of several main flavor components in the prepared Jingshan tea paste

[0094]

[0095] Caffeine, catechins, tea polyphenols, free amino acids, etc. are the main flavor components of tea extracts including tea extracts. The differences in these flavor components between the Jingshan tea extracts obtained by the preparation method of the present invention (Examples 1 and 2) and the Jingshan tea extracts prepared by the boiling water bath method for comparison (Comparative Example 1) are compared, and the results are shown in Table 4. The total catechins, tea polyphenols and free amino acid contents of the tea extract obtained by the present invention are higher than those of the tea extract prepared by the traditional boiling water bath method, and the caffeine content is relatively close. The difference in these components is one of the important reasons for the significant difference in their sensory evaluation taste.

[0096] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A method for preparing Jingshan Camellia Extract by using a transformer-type magnetic induction electric field-enzyme coupling method, Features The following steps are involved: 1) Adjust the pH of pure water to 5.0-6.5 to obtain acid-adjusted pure water; Then, according to the material-liquid ratio of 1g:20-30ml, weigh the camellia sinensis powder and add it into the above-mentioned acid-adjusted pure water to allow the camellia sinensis powder to absorb water and swell for 0.5-1.5h; 2) Add chitosan-immobilized hydrolase to the liquid obtained in step 1) at a dosage ratio of 100 to 1500 U of hydrolase per 1 g of camellia powder, mix well and load into a magnetic induction device; 3) First, evacuate the magnetic induction device, and then fill it with inert gas to normal pressure; 4) Adjust the magnetic induction voltage to 400-600V and extract for 35-45min under stirring; 5) Adjust the magnetic induction voltage to 900-1100V and extract for 15-25min under stirring; 6) Turn off the magnetic induction, release the inert gas, centrifuge the liquid obtained in step 5), and concentrate the obtained supernatant by vacuum rotary evaporation to a paste to obtain Jingshan Camellia Paste.

2. The method for preparing Jingshan Camellia Extract by using a transformer-type magnetic induction electric field-enzyme coupling method according to claim 1, Features In the step 2), the hydrolase is at least any one of the following: β-glucosidase, α-glucosidase, β-galactosidase, cellulase.

3. The method for preparing Jingshan Camellia Extract by using a transformer-type magnetic induction electric field-enzyme coupling method according to claim 2, Features Step 6): Centrifugation is 4500-5500 rpm for 8-12 minutes; The evaporation temperature is 45-55°C; The solid content of Jingshan camellia paste is 60-70%.

4. The method for preparing Jingshan Camellia Extract by using a transformer-type magnetic induction electric field-enzyme coupling method according to claim 3, Features: The Jingshan tea was crushed and passed through a 60±10 mesh sieve to obtain the Jingshan tea powder.

5. The method for preparing Jingshan Camellia Extract by using a transformer-type magnetic induction electric field-enzyme coupling method according to claim 4, Features: The inert gas in step 3) is nitrogen or argon.

6. The method for preparing Jingshan Camellia Extract by using a variable voltage magnetic induction electric field-enzyme coupling method according to any one of claims 1 to 5, Features: The step 4) is: adjusting the magnetic induction voltage to 500V and extracting for 40 minutes; The step 5) is: adjusting the magnetic induction voltage to 1000 V and extracting for 20 minutes.

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