Instant active jasmine tea processing technology

Abstract

The invention relates to an instant active jasmine tea processing technology, and belongs to the technical field of tea processing. The jasmine tea and the water are subjected to ultrasonic treatment at room temperature, so that active ingredients of the jasmine tea can be activated, the activity during later extraction is improved, the active ingredients are easier to extract, and the catechin content, the amino acid content, the flavone content and the soluble sugar content in the instant jasmine tea are improved. According to the preparation method disclosed by the invention, the instant jasmine flower tea which is relatively high in brightness L value, light transmittance, dissolution rate, catechin content, amino acid content, flavone content and soluble sugar content and relatively low in caffeine content at the same time is obtained by optimizing the parameters of the processing technologies of all the steps, and the instant jasmine flower tea meets related national standard requirements.

Description

Technical Field

[0001] The invention relates to an instant processing technology for active jasmine tea, belonging to the technical field of tea processing. Background Art

[0002] Instant tea is an important deep-processed tea product. It refers to a new type of beverage in granular or powder form that is easily soluble in water and has no tea residues, made from finished tea, semi-finished tea, tea by-products or fresh leaves through extraction, filtration, concentration, drying and other processes. Compared with traditional brewing methods, instant tea has the advantages of a wide range of raw material sources, convenient and fast drinking methods, economy and environmental protection, high content of effective ingredients and reduced pesticide residues.

[0003] Jasmine tea is a reprocessed tea with a long history and is loved by consumers, especially those in the north. Jasmine tea is made by mixing jasmine flowers and tea leaves together. It not only maintains the freshness of green tea, but also has the fragrance of jasmine flowers. Special jasmine tea refers to jasmine tea made from famous green tea as the tea base and high-quality jasmine flowers. There are also jasmine instant teas on the market, but the effective ingredients of jasmine tea are lost during the processing process, and the brewed tea is mostly bland and tasteless.

[0004] Therefore, it is necessary to develop a jasmine instant tea with good water solubility and mouthfeel simultaneously. Summary of the invention

[0005] The invention aims to provide a processing technology for instant active jasmine tea to obtain instant active jasmine tea with good water solubility and taste.

[0006] The invention provides an active jasmine tea instant processing technology, comprising the following steps: subjecting a mixture consisting of jasmine tea and water to ultrasonic treatment, ultrasonic heating extraction, solid-liquid separation, and then concentrating the liquid obtained by solid-liquid separation to obtain a concentrated liquid, and then sterilizing, freezing, and crushing the concentrated liquid to obtain a frozen powder, and finally vacuum freeze-drying the frozen powder to obtain active jasmine instant tea; the ultrasonic frequency during the ultrasonic treatment is 25-35kHz, and the power density is 0.6-0.9W / cm 2 , the temperature is 25~30℃; the temperature during ultrasonic heating extraction is 60~70℃, and during ultrasonic heating extraction, periodic ultrasound is applied, each ultrasound is 5~8min, and ultrasound is stopped for 15~20min. The ultrasonic frequency is 40~50kHz, and the power density is 0.8~1.2W / cm 2 ; The freezing treatment temperature is -100~-80℃.

[0007] Preferably, the mass ratio of jasmine tea to water is 1:(20-30).

[0008] Preferably, the ultrasonic treatment time is 1.5 to 3 hours.

[0009] Preferably, the ultrasonic heating extraction time is 2 to 3 hours.

[0010] Preferably, the solid content of the concentrate is 25% to 35%.

[0011] Preferably, the freezing treatment time is 5 to 10 minutes.

[0012] Preferably, the average particle size of the frozen powder is 4 to 8 mm.

[0013] Preferably, the vacuum degree of vacuum freeze drying is 0.1~0.15Pa.

[0014] Preferably, the vacuum freeze-drying temperature is -80 to -75°C.

[0015] Preferably, the vacuum freeze-drying time is 25 to 32 hours.

[0016] The beneficial effects of the present invention are as follows: (1) The present invention can activate the effective components of jasmine tea by ultrasonically treating jasmine tea and water at room temperature, thereby improving the activity during subsequent extraction, making it easier to extract the effective components, and increasing the catechin content, amino acid content, flavonoid content and soluble sugar content in jasmine instant tea.

[0017] (2) The present invention achieves comprehensive optimization of the sensory indicators and physical and chemical indicators of jasmine instant tea by optimizing the ultrasonic frequency, power density, temperature and time during room temperature ultrasonic treatment, and optimizing the ultrasonic frequency, power density, temperature and time during ultrasonic extraction. It can simultaneously improve the brightness, light transmittance, solubility, catechin content, amino acid content, flavonoid content and soluble sugar content of jasmine tea, and reduce the caffeine content, so as to obtain high-quality jasmine instant tea.

[0018] (3) The present invention optimizes the concentration of the jasmine tea concentrate, pre-freezes the concentrate and crushes it into small particles, thereby promoting the sublimation of water during the subsequent freeze-drying process, while reducing excessive structural changes caused by the sublimation of water during the subsequent freeze-drying process, thereby improving the brightness L value, light transmittance and solubility rate of the jasmine instant tea.

[0019] (4) The present invention optimizes the parameters of each step of the processing technology to obtain jasmine instant tea with higher brightness L value, transmittance, solubility rate, catechin content, amino acid content, flavonoid content, soluble sugar content and lower caffeine content, which meets the requirements of relevant national standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a schematic diagram of the sensory score and brightness change curve of the active jasmine instant tea processed in each embodiment and comparative example of the present invention; Figure 2 It is a schematic diagram of the change curve of light transmittance and dissolution rate of active jasmine instant tea processed in various embodiments and comparative examples of the present invention; Figure 3 The present invention is a schematic diagram of the change curves of catechin content, caffeine content, amino acid content, flavonoid content and soluble sugar content of the active jasmine instant tea processed in various embodiments and comparative examples of the present invention. DETAILED DESCRIPTION

[0021] The following examples are intended to further illustrate the present invention rather than to limit the scope of protection of the present invention. Example

[0022] The instant active jasmine tea processing technology of this embodiment comprises the following steps: (1) Add jasmine tea and water into a mixing container, the mass ratio of jasmine tea to water is 1:20, and then place the mixing container in an ultrasonic water bath for ultrasonic treatment, the ultrasonic frequency is 25kHz, and the power density is 0.6W / cm 2 , temperature is 25℃, time is 1.5h.

[0023] (2) After the ultrasonic treatment, turn on the heating switch of the ultrasonic water bath, turn off the ultrasonic switch, heat the material in the mixing container to 60°C, and then turn on the ultrasonic switch to perform ultrasonic heating extraction. During ultrasonic heating extraction, apply periodic ultrasonic waves to the material in the mixing container, ultrasonically for 5 minutes, and stop ultrasonicating for 15 minutes. The ultrasonic frequency is 40 kHz and the power density is 0.8 W / cm 2 The ultrasonic heating extraction time was 2h.

[0024] (3) After the ultrasonic heating extraction is completed, the material in the mixing container is filtered through gauze, and the filtrate is collected, which is the extract; the extract is concentrated on a rotary evaporator to obtain a concentrated solution, and the solid content of the concentrated solution is 25%; the concentrated solution is sterilized at high temperature and poured into a culture dish, and the culture dish is placed in a freezer for freezing to obtain a frozen product, and then the frozen product is crushed to obtain frozen powder; the freezing temperature is -100°C, the time is 5 minutes, and the average particle size of the frozen powder is 4 mm.

[0025] (4) placing the frozen powder in a vacuum freeze dryer for vacuum freeze drying and then sealing and packaging to obtain active jasmine instant tea; wherein the vacuum degree of the vacuum freeze drying is 0.1 Pa, the temperature is -80°C, and the time is 25 hours. Example

[0026] The instant active jasmine tea processing technology of this embodiment comprises the following steps: (1) Jasmine tea and water were added into a mixing container, the mass ratio of jasmine tea to water was 1:30, and then the mixing container was placed in an ultrasonic water bath for ultrasonic treatment, the ultrasonic frequency was 35 kHz, and the power density was 0.9 W / cm 2 , temperature is 30℃, time is 3h.

[0027] (2) After the ultrasonic treatment, turn on the heating switch of the ultrasonic water bath, turn off the ultrasonic switch, heat the material in the mixing container to 70°C, and then turn on the ultrasonic switch to perform ultrasonic heating extraction. During ultrasonic heating extraction, apply periodic ultrasonic waves to the material in the mixing container, ultrasonically for 8 minutes, and stop ultrasonicating for 20 minutes. The ultrasonic frequency is 50 kHz and the power density is 1.2 W / cm 2 The ultrasonic heating extraction time was 3h.

[0028] (3) After the ultrasonic heating extraction is completed, the material in the mixing container is filtered through gauze, and the filtrate is collected to obtain the extract; the extract is concentrated on a rotary evaporator to obtain a concentrated solution, and the solid content of the concentrated solution is 35%; the concentrated solution is sterilized at high temperature and poured into a culture dish, and the culture dish is placed in a freezer for freezing to obtain a frozen product, and then the frozen product is crushed to obtain frozen powder; the freezing temperature is -80°C, the time is 10 min, and the average particle size of the frozen powder is 8 mm.

[0029] (4) placing the frozen powder in a vacuum freeze dryer for vacuum freeze drying and then sealing and packaging to obtain active jasmine instant tea; wherein the vacuum degree of the vacuum freeze drying is 0.15 Pa, the temperature is -75°C, and the time is 30 hours. Example

[0030] The instant active jasmine tea processing technology of this embodiment comprises the following steps: (1) Jasmine tea and water were added into a mixing container, the mass ratio of jasmine tea to water was 1:25, and then the mixing container was placed in an ultrasonic water bath for ultrasonic treatment, the ultrasonic frequency was 30 kHz, and the power density was 0.7 W / cm 2 , temperature is 28℃, time is 2h.

[0031] (2) After the ultrasonic treatment, turn on the heating switch of the ultrasonic water bath, turn off the ultrasonic switch, heat the material in the mixing container to 65°C, and then turn on the ultrasonic switch to perform ultrasonic heating extraction. During ultrasonic heating extraction, apply periodic ultrasonic waves to the material in the mixing container, and ultrasonic waves are applied for 6 minutes each time and stopped for 18 minutes. The ultrasonic frequency is 45kHz and the power density is 1W / cm 2 The ultrasonic heating extraction time was 2.5h.

[0032] (3) After the ultrasonic heating extraction is completed, the material in the mixing container is filtered through gauze, and the filtrate is collected, which is the extract; the extract is concentrated on a rotary evaporator to obtain a concentrated solution, and the solid content of the concentrated solution is 30%; the concentrated solution is sterilized at high temperature and poured into a culture dish, and the culture dish is placed in a freezer for freezing to obtain a frozen product, and then the frozen product is crushed to obtain frozen powder; the freezing temperature is -90°C, the time is 7 minutes, and the average particle size of the frozen powder is 6 mm.

[0033] (4) placing the frozen powder in a vacuum freeze dryer for vacuum freeze drying and then sealing and packaging to obtain active jasmine instant tea; wherein the vacuum degree of the vacuum freeze drying is 0.1 Pa, the temperature is -75°C, and the time is 32 hours.

[0034] Comparative Example 1 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that step (1) is omitted in the instant processing technology of active jasmine tea of ​​this comparative example.

[0035] Comparative Example 2 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the ultrasonic frequency in step (1) of the instant processing technology of active jasmine tea of ​​this comparative example is 20 kHz.

[0036] Comparative Example 3 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the ultrasonic frequency in step (1) of the instant processing technology of active jasmine tea of ​​this comparative example is 40 kHz.

[0037] Comparative Example 4 The difference between the instant processing technology of active jasmine tea in this comparative example and the instant processing technology of active jasmine tea in Example 1 is that the ultrasonic power density in step (1) of the instant processing technology of active jasmine tea in this comparative example is 0.4 W / cm 2 .

[0038] Comparative Example 5 The difference between the instant processing technology of active jasmine tea in this comparative example and the instant processing technology of active jasmine tea in Example 1 is that the ultrasonic power density in step (1) of the instant processing technology of active jasmine tea in this comparative example is 1 W / cm 2 .

[0039] Comparative Example 6 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the temperature of ultrasonic treatment in step (1) of the instant processing technology of active jasmine tea of ​​this comparative example is 20°C.

[0040] Comparative Example 7 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the temperature of ultrasonic treatment in step (1) of the instant active jasmine tea processing technology of this comparative example is 35°C.

[0041] Comparative Example 8 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the temperature of ultrasonic heating extraction in step (2) of the instant active jasmine tea processing technology of this comparative example is 55°C.

[0042] Comparative Example 9 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the temperature of ultrasonic heating extraction in step (2) of the instant active jasmine tea processing technology of this comparative example is 75°C.

[0043] Comparative Example 10 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the ultrasonic frequency in step (2) of the instant processing technology of active jasmine tea of ​​this comparative example is 35 kHz.

[0044] Comparative Example 11 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the ultrasonic frequency in step (2) of the instant processing technology of active jasmine tea of ​​this comparative example is 55 kHz.

[0045] Comparative Example 12 The difference between the instant processing technology of active jasmine tea in this comparative example and the instant processing technology of active jasmine tea in Example 1 is that the power density of the ultrasonic wave in step (2) of the instant processing technology of active jasmine tea in this comparative example is 0.6 W / cm 2 .

[0046] Comparative Example 13 The difference between the instant processing technology of active jasmine tea in this comparative example and the instant processing technology of active jasmine tea in Example 1 is that the power density of the ultrasonic wave in step (2) of the instant processing technology of active jasmine tea in this comparative example is 1.5 W / cm 2 .

[0047] Comparative Example 14 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the time of ultrasonic heating extraction in step (2) of the instant active jasmine tea processing technology of this comparative example is 1.5 hours.

[0048] Comparative Example 15 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the time of ultrasonic heating extraction in step (2) of the instant active jasmine tea processing technology of this comparative example is 3.5 hours.

[0049] Comparative Example 16 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the ultrasonic treatment for 5 minutes in step (2) of the instant processing technology of active jasmine tea of ​​this comparative example is adjusted to 3 minutes.

[0050] Comparative Example 17 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the ultrasonic treatment for 5 minutes in step (2) of the instant processing technology of active jasmine tea of ​​this comparative example is adjusted to 10 minutes.

[0051] Comparative Example 18 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the solid content of the concentrated solution in step (3) of the instant processing technology of active jasmine tea of ​​this comparative example is 20%.

[0052] Comparative Example 19 The difference between the instant processing technology of active jasmine tea of ​​this comparative example and the instant processing technology of active jasmine tea of ​​Example 1 is that the solid content of the concentrated solution in step (3) of the instant processing technology of active jasmine tea of ​​this comparative example is 40%.

[0053] Comparative Example 20 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the freezing temperature in step (3) of the instant active jasmine tea processing technology of this comparative example is -120°C.

[0054] Comparative Example 21 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the freezing temperature in step (3) of the instant active jasmine tea processing technology of this comparative example is -70°C.

[0055] Comparative Example 22 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the freezing time in step (3) of the instant active jasmine tea processing technology of this comparative example is 3 minutes.

[0056] Comparative Example 23 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the freezing time in step (3) of the instant active jasmine tea processing technology of this comparative example is 12 minutes.

[0057] Comparative Example 24 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the average particle size of the frozen powder in step (3) of the instant active jasmine tea processing technology of this comparative example is 3 mm.

[0058] Comparative Example 25 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the average particle size of the frozen powder in step (3) of the instant active jasmine tea processing technology of this comparative example is 10 mm.

[0059] Comparative Example 26 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the vacuum freeze-drying temperature in step (4) of the instant active jasmine tea processing technology of this comparative example is -85°C.

[0060] Comparative Example 27 The difference between the instant active jasmine tea processing technology of this comparative example and the instant active jasmine tea processing technology of Example 1 is that the vacuum freeze-drying temperature in step (4) of the instant active jasmine tea processing technology of this comparative example is -70°C.

[0061] Experimental example In this experimental example, sensory evaluation and physical and chemical composition analysis of the active jasmine instant tea processed in each embodiment and comparative example were carried out according to the method in the standard GB / T 31740.1-2015 "Tea Products Part 1: Solid Instant Tea". The sensory evaluation method is as follows: weigh 0.50g of the sample, put it in a 250mL transparent glass cup, brew it with 150mL of pure water with a water temperature of 85℃±5℃ to obtain tea liquid, and sensory evaluate the aroma, taste and soup color of the tea liquid. The evaluation results are scored in a percentage system, wherein the aroma, taste and soup color account for 20 points, 40 points and 40 points respectively in the total score of 100 points, and the scoring standards are shown in Table 1. At the same time, the brightness L value, light transmittance and solubility of the tea liquid are measured. The test method of dissolution rate is as follows: weigh 5.0g of sample, place it in a 25mL transparent glass cup, add 8g of water, stir the material in the transparent glass cup with a magnetic stirrer at 25℃, the speed is 100r / min, stir for 25min, filter, collect the filtrate, calculate the mass of sample dissolved in water, and calculate the sample dissolution rate by using the mass of sample dissolved and the total mass of sample. The physical and chemical component analysis includes the analysis of catechin content, caffeine content, amino acid content, flavonoid content and soluble sugar content of active jasmine instant tea. The catechin content is determined according to the method specified in standard GB / T21727. The caffeine content is determined according to the method specified in standard ISO10727:2002. The amino acid content is determined by ninhydrin colorimetry, the flavonoid content is determined by aluminum chloride colorimetry, and the soluble sugar content is determined by anthrone colorimetry. During the test, 5 samples are selected for each indicator, and the average value of the 3 test results is taken as the final test result. The sensory scores, brightness, light transmittance and dissolution rate test results of the active jasmine instant tea processed in each embodiment and comparative example are shown in Table 2. Figure 1 and Figure 2 The catechin content, caffeine content, amino acid content, flavonoid content and soluble sugar content are shown in Table 3 and Figure 3 shown.

[0062] Table 1 Sensory index scoring table

[0063] Table 2 Sensory scores, brightness, light transmittance and dissolution rate test results of active jasmine instant tea processed in various embodiments and comparative examples

[0064] Table 3 Catechin content, caffeine content, amino acid content, flavonoid content and soluble sugar content of active jasmine instant tea processed in various examples and comparative examples

[0065] As shown in Table 2 and Table 3, the ultrasonic frequency, power density, temperature and time during room temperature ultrasonic treatment, and the ultrasonic frequency, power density, temperature and time during ultrasonic extraction all have an impact on the brightness, light transmittance, dissolution rate, catechin content, amino acid content, flavonoid content and soluble sugar content of jasmine tea. In addition, the concentration of jasmine tea concentrate, the temperature of freezing treatment and the particle size of frozen powder also have an impact on the brightness, light transmittance, dissolution rate, catechin content, amino acid content, flavonoid content and soluble sugar content of jasmine tea. In summary, the present invention obtains jasmine instant tea with higher brightness L value, light transmittance, dissolution rate, catechin content, amino acid content, flavonoid content, soluble sugar content and lower caffeine content by optimizing the parameters of each step processing technology.

Claims

1. A process for instant active jasmine tea, characterized in that: The following steps are involved: The mixture of jasmine tea and water is subjected to ultrasonic treatment, ultrasonic heating extraction, solid-liquid separation in sequence, and the liquid obtained by solid-liquid separation is concentrated to obtain a concentrated liquid, and the concentrated liquid is sterilized, frozen, and crushed to obtain a frozen powder, and finally the frozen powder is vacuum freeze-dried to obtain active jasmine instant tea; the ultrasonic frequency during the ultrasonic treatment is 25-35kHz, and the power density is 0.6-0.9W / cm 2 , the temperature is 25~30℃; the temperature during ultrasonic heating extraction is 60~70℃, and during ultrasonic heating extraction, periodic ultrasound is applied, each ultrasound is 5~8min, and ultrasound is stopped for 15~20min. The ultrasonic frequency is 40~50kHz, and the power density is 0.8~1.2W / cm 2 ; The freezing treatment temperature is -100~-80℃.

2. The instant active jasmine tea processing technology according to claim 1, characterized in that: The mass ratio of jasmine tea to water is 1:(20~30).

3. The instant active jasmine tea processing technology according to claim 1 or 2, characterized in that: The ultrasonic treatment time is 1.5~3h.

4. The instant active jasmine tea processing technology according to claim 1, characterized in that: The ultrasonic heating extraction time is 2~3h.

5. The instant active jasmine tea processing technology according to claim 1 or 4, characterized in that: The solid content of the concentrate is 25%~35%.

6. The instant active jasmine tea processing technology according to claim 1, characterized in that: The freezing treatment time is 5 to 10 minutes.

7. The instant active jasmine tea processing technology according to claim 1 or 6, characterized in that: The average particle size of frozen powder is 4~8mm.

8. The instant active jasmine tea processing technology according to claim 1, characterized in that: The vacuum degree of vacuum freeze drying is 0.1~0.15Pa.

9. The instant active jasmine tea processing technology according to claim 1 or 8, characterized in that: The temperature of vacuum freeze drying is -80~-75℃.

10. The instant active jasmine tea processing technology according to claim 1 or 8, characterized in that: The vacuum freeze-drying time is 25~32h.

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