CN113973955A

CN113973955A - Tea concentrated solution and preparation method thereof

Info

Publication number: CN113973955A
Application number: CN202111210784.7A
Authority: CN
Inventors: 胡玉荣; 张顶武; 陈家伯
Original assignee: Shanghai Kangshi Food Technology Co ltd
Current assignee: Shanghai Kangshi Food Technology Co ltd
Priority date: 2021-10-18
Filing date: 2021-10-18
Publication date: 2022-01-28

Abstract

The tea concentrate and the preparation method thereof according to the embodiment of the present invention are obtained by wetting finished tea leaves with water; and then, under the pressure condition of 0.011-0.057 MPa, introducing steam to treat the tea wetted by water, and then collecting steam condensate containing aroma components, which is beneficial to obtaining a tea aroma recovery liquid with higher natural tea aroma concentration, and meanwhile, under the pressure condition of 0.011-0.057 MPa, the temperature of the steam is lower, so that the green odor caused by decomposition of some heat-sensitive aromas due to overhigh temperature can be prevented, and the aroma flavor is more natural.

Description

Tea concentrated solution and preparation method thereof

Technical Field

The invention belongs to the field of food and beverage, and particularly relates to a tea concentrated solution and a preparation method thereof.

Background

The tea beverage market is rapidly developed in recent years, and with the improvement of living standard of people, the requirements of consumers on health, naturalness and taste quality of tea beverages are higher and higher. Pure tea beverage comes from birth, market share is gradually increased, no additive is added, pure nature is the main trend of future development of tea beverage, but the tea beverage without sugar and essence is difficult to meet the requirements on aroma and taste and flavor by extracting tea only and blending, so that the tea concentrated solution is added in the blending process to improve the product taste and increase the tea charm.

The concentrated tea liquid is prepared with tea or fresh tea leaf as main material and through water extraction or fresh tea leaf juice extraction, and may be added with food additive and food processing assistant to eliminate water in certain proportion physically and processed into liquid product as food, beverage and other supplementary material.

However, because tea aroma components are poor in thermal stability and volatile, most of tea aroma is lost in the processing processes of long-time extraction, concentration and the like in the production process of the traditional tea concentrated solution, and the tea beverage prepared by using the concentrated solution still needs to be added with aroma to supplement the tea aroma.

The method mainly comprises the step of recovering the aroma of the raw tea or finished tea by steam distillation, the method for distilling the raw tea by steam is favorable for recovering the aroma, but the requirement on the tea is higher, and domestic tea raw materials mainly comprise finished tea, so the application range of the method is limited to a great extent, and the current method for distilling the finished tea by steam has the problem of low aroma recovery content.

Disclosure of Invention

In order to solve the above problems in the conventional method of recycling aroma of tea leaves by using steam, a specific embodiment of the present invention provides a tea concentrate and a method for preparing the same, wherein the tea concentrate comprises:

a preparation method of tea concentrated solution comprises the following aroma extraction steps:

wetting the finished tea leaves with water;

and then, under the pressure condition of 0.011-0.057 MPa, introducing steam to treat the tea leaves wetted by water, and collecting steam condensate containing aroma components to obtain aroma condensate A.

Optionally, the finished tea is moistened with water at a temperature above 65 ℃.

Optionally, the length of the tea leaves is 1-5 mm.

Optionally, the preparation method further comprises the following extraction steps: and (3) treating the tea leaves treated by the water vapor according to the weight ratio of the tea leaves to the water of 1: 2-1: 10 extracting to obtain extract B, wherein the extraction temperature is 25-90 ℃, and the extraction time is 1-60 min.

Optionally, the preparation method further comprises the following enzymolysis and concentration steps: and (3) mixing the extracted tea leaves according to the weight ratio of the tea leaves to the water of 1: 5-1: 10, leaching at the temperature of 70-95 ℃ for 5-60 min, cooling to 40-50 ℃, adding enzyme for enzymolysis, filtering tea leaves after enzymolysis is finished to obtain tea soup, and concentrating the tea soup until the content of soluble solid solution accounts for 30-50 wt% to obtain concentrated solution C.

Optionally, the filtering is performed in the following manner: performing primary filtration by using a filter press, then performing centrifugal secondary filtration, and performing cross-flow filtration.

Optionally, the enzymolysis is performed in the following manner: firstly adding tannase for enzymolysis for 10 min-1 h, and then adding protease and pentosanase for enzymolysis for 0.5 h-3 h.

Optionally, the preparation method further comprises the following compounding steps: and mixing the aroma condensate A, the extract B and the concentrated solution C according to the weight ratio of 0.5-2: 1-4: 0.5-1.5 weight ratio.

A tea concentrate prepared by the above preparation method.

The tea concentrate and the preparation method thereof according to the embodiment of the present invention are obtained by wetting finished tea leaves with water; then, under the pressure condition of 0.011-0.057 MPa, introducing steam to treat the tea leaves wetted by water, and then collecting steam condensate containing aroma components, which is beneficial to obtaining tea aroma recovery liquid with higher natural tea aroma concentration, and meanwhile, under the pressure condition of 0.011-0.057 MPa, the temperature of the steam is lower, so that the green odor caused by decomposition of some heat-sensitive aromas due to overhigh temperature can be prevented, and the aroma flavor is more natural.

Detailed Description

The inventor of the application discovers that some heat-sensitive aroma components in the finished tea can cause structural change due to heating and have larger difference with the aroma characteristics of the tea raw materials to cause green odor because the process is in a high-temperature closed environment condition after the finished tea is treated by introducing steam, when the finished tea is wetted by water and the pressure in the process is controlled to be 0.011-0.057 MPa, the steam temperature of the steam corresponding to the pressure is 50-85 ℃, the low steam temperature can effectively prevent the decomposition of the heat-sensitive aroma components, and meanwhile, the combination of the wetting of the finished tea by water at low pressure is more beneficial to the escape and collection of the aroma components in the tea. Thus, a specific embodiment of the present invention provides a method for preparing a tea concentrate comprising the following aroma extraction steps: wetting the finished tea leaves with water; and then, under the pressure condition of 0.011-0.057 MPa, introducing steam to treat the tea leaves wetted by water, and collecting steam condensate containing aroma components to obtain aroma condensate A.

In some embodiments, the aroma extraction is performed by an aroma extraction system comprising a water vapor generator, a reactor, a condenser, a collector and a vacuum device, wherein the finished tea leaves are placed in the reactor, the reactor can be a cylindrical or barreled container, and the like, one end of the reactor is connected with the water vapor generator, the other end of the reactor is connected with the condenser, water vapor prepared by the water vapor generator enters the reactor and contacts with the finished tea leaves in the reactor to extract aroma components in the tea leaves, then the water vapor and the aroma components enter the condenser to be condensed and liquefied, and then the condensed and liquefied water vapor and aroma components are collected by the collector to obtain aroma condensate A, the pressure is controlled to be 0.011-0.057 MPa in the whole aroma extraction process. In some embodiments, the reactor is further provided with a stirring device for stirring the finished tea leaves during the treatment of the finished tea leaves with steam, in order to allow the finished tea leaves to be sufficiently contacted with the steam.

In some embodiments, the finished tea leaf is any one of green tea, oolong tea, black tea, and the like, wherein the green tea may be any one or a combination of two or more of steamed green tea, roasted green tea, sun-dried green tea, or roasted green tea, the oolong tea may be one or a mixture of two or more of north-minea oolong tea, south-minnan oolong tea, guangdong oolong tea, alpine oolong tea, and the like, and the black tea may be any one or a mixture of two or more of congou black tea, young black tea, broken black tea, and the like.

In some embodiments, the tea concentrate of the present invention is prepared by wetting 1 part by weight of the finished tea leaves with 0.1 to 10 parts by weight of water before the steam treatment, for example, by spraying 1 part by weight of the finished tea leaves with 0.1 part by weight, 0.5 part by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, or 10 parts by weight of purified water before the steam treatment.

In the preparation method of the tea concentrated solution of the embodiment of the invention, the finished tea leaves are wetted by water with the temperature of 25-95 ℃ in some embodiments, and are further wetted by water with the temperature of more than 65 ℃ and more than 90 ℃ in some embodiments, and the temperature is more favorable for recovering and extracting the aroma.

In some specific embodiments, the length of the finished tea leaves is 1-5 mm, and specifically, the tea leaves with the length can be obtained by chopping or crushing, and the finished tea leaves with the length can be adopted, so that the aroma recovery concentration is higher, and the higher aroma recovery efficiency is achieved.

In some embodiments, the flow rate of the water vapor is 4kg/h to 95kg/h, specifically, for example, 5kg/h, 10kg/h, 20kg/h, 30kg/h, 40kg/h, 60kg/h, 70kg/h, 80kg/h or 90kg/h, etc., based on 100kg of finished tea leaves, the recovery time is 0.5h to 2h, and the weight of the aroma condensate A is 50 kg to 200 kg.

In some embodiments, the method of making a tea concentrate of embodiments of the present invention further comprises the steps of: and (3) treating the finished tea leaves treated by the water vapor according to the weight ratio of the finished tea leaves to water of 1: 2-1: 10 extracting to obtain extract B, wherein the extraction temperature is 25-90 ℃, and the extraction time is 1-60 min. Through the extraction step, the finished tea after aroma recovery is subjected to one-time short-time extraction, and the obtained extract has more natural tea flavor.

In some embodiments, the method further comprises the following steps of performing enzymatic concentration: and (3) mixing the extracted tea leaves according to the weight ratio of finished tea leaves to water of 1: 5-1: 10, leaching at the temperature of 70-95 ℃ for 5-60 min, cooling to 40-50 ℃, adding enzyme for enzymolysis, filtering tea leaves after enzymolysis is finished to obtain tea soup, and concentrating the tea soup until the content of soluble solid solution accounts for 30-50 wt% to obtain concentrated solution C. In some embodiments, the enzyme is added in an amount of 1 wt% to 5 wt% based on the weight of the finished tea material. In some embodiments, the enzyme may be, for example, one or more of tannase, protease, pentosanase, pectinase, carbohydrase, or the like. In some specific embodiments, tannase is added for enzymolysis for 10min to 1h, and then protease and pentosanase are added for enzymolysis for 0.5h to 3 h. The addition amount of the protease is 1-5 wt% of the weight of finished tea, the addition amount of the pentosanase is 0.02-2 wt% of the weight of the finished tea, the addition amount of the tannase is 0.01-1 wt% of the weight of the finished tea, the protease decomposes protein in the tea into amino acid, the delicate flavor of the tea soup is improved, the pentosanase has pectinase and various diastase activities, multiple activities of complex enzymes of the pentosanase destroy cell walls, the content of soluble solids in the tea soup is increased, the sweet feeling of the tea soup is increased, the tannase can improve the muddy state of the tea soup after cooling, the clarity is improved, and the bitter taste is weakened.

In some embodiments, the filtration is performed by: the tea soup is filtered by a filter press for the first time, then is filtered by centrifugation for the second time, and then is filtered by cross flow, and the clarity of the tea soup can be obviously improved by adopting the mode for filtering.

In some embodiments, the step of performing enzymatic hydrolysis concentration further includes a sterilization step of sterilizing the filtered tea soup, and performing instantaneous heating and high temperature sterilization at a sterilization temperature: and (3) the temperature is 90-95 ℃ for 15-60 s, in some specific embodiments, the sterilization comprises two steps, wherein one step of sterilization is performed after one-time filtration, and one step of sterilization is performed after cross-flow filtration.

In some embodiments, the concentration is performed by a rotary thin film evaporator, and the concentration temperature is 30-70 ℃.

In some embodiments, the preparation method further comprises the following compounding step: and mixing the aroma condensate A, the extract B and the concentrated solution C according to the weight ratio of 0.5-2: 1-4: 0.5-1.5, and the obtained tea concentrated solution can achieve the best flavor effect by using the compounding way.

In some embodiments, the method further comprises the following steps of sterilizing the finished product: and (3) performing heat sterilization on the compounded tea concentrated solution, rapidly cooling to 60-70 ℃, performing heat canning, then cooling to normal temperature, or cooling to normal temperature and then performing aseptic canning, wherein the heat sterilization adopts a plate sterilizer or a tubular sterilizer, or the sterilization adopts a sterilization kettle after the canning of the product is finished.

The present invention is further illustrated by the following specific examples.

Examples

Sensory evaluation

The content of soluble solid solution in the concentrated tea solution is diluted to 0.3 wt%, and then 10 trained evaluators evaluate the aroma, sweetness, fullness, bitterness and overall sensory flavor of the tea, and record the average score. The scoring criteria were: very good, 8-10 minutes; good, 6-8 min; slightly better, 4-6 min; slightly worse, 2-4 minutes; the difference is 0-2 min; very poor, 0 min.

Example 1

Preparation of aroma condensate A

100kg of oolong tea leaves are put into a reactor, 100kg of RO water with the temperature of 25 +/-2 ℃, 65 +/-2 ℃ and 95 +/-2 ℃ is respectively sprayed to uniformly wet the tea leaves, fragrance recovery equipment is sealed and the pressure is adjusted to 0.024MPa, the steam temperature is 65 +/-2 ℃, the steam flow is 95kg/h, and fragrance is recovered for 2h to obtain fragrance condensate A.

Preparation of extract B

Extracting the oolong tea leaves with closed extraction equipment, recovering aroma, adding RO water of 85 + -2 deg.C 300kg, and extracting for 5 min. And separating the tea water after the extraction is finished to obtain extract B.

Preparation of concentrate C

Adding 1000kg of RO water with the temperature of 85 +/-2 ℃ into the extracted tea leaves, leaching for 15min, and cooling to 45 ℃ after the extraction is finished; firstly, 0.1kg of tannase is added, and the enzymolysis reaction is carried out for 1 h; then, 1.5kg of Protease (Protease A2SD, wild) and 0.6kg of pentosanase (Viscozyme L, Novoxil) were added, and the enzymatic reaction was continued for 3 hours. The temperature in the enzymolysis reaction process is controlled to be 45 +/-2 ℃. After the enzymolysis reaction is finished, a filter press is adopted for primary filtration, tea residues are separated to obtain tea soup, the tea soup is sterilized at high temperature by a plate type sterilizer for 60s at 90 ℃, then a disc centrifuge and a filter element filter are adopted for secondary filtration, then cross flow filtration is carried out for fine filtration, the fine filtration liquid is sterilized at high temperature by the plate type sterilizer for 15s at 95 ℃, then a rotary evaporator is used for concentration at 30 +/-2 ℃, and the concentration is adjusted to 20-30 wt% of soluble solid solution (Brix) to obtain concentrated solution C.

Compounding

Mixing the aroma condensate A, the extract B and the concentrated solution C according to the proportion of 1: 1.5: 1.5, compounding to obtain the high-aroma concentrated tea solution.

Sterilizing the finished product

Sterilizing the compounded high-aroma oolong tea concentrated solution at high temperature by adopting a plate sterilizer, sterilizing at 110 ℃ for 30s, quickly cooling, hot canning at 60 ℃, cooling to room temperature to finally prepare the high-aroma oolong tea concentrated solution, and evaluating the sensitivity of the high-aroma oolong tea concentrated solution, wherein the results are shown in the following table 1.

Comparative example 1

Comparative product 1 was prepared in exactly the same manner as in example 1 except that the tea leaves were not moistened in the aroma recovery stage, and the results of sensory evaluation are shown in table 1 below.

Table 1 table of sensory evaluation and evaluation results of the high-aroma oolong tea concentrated solution of example 1 and comparative product 1 of comparative example 1

As can be seen from the evaluation results in table 1 above, in comparative example 1, the tea leaves were not sufficiently moistened, and the aroma of the dried tea was recovered without any change, and the obtained aroma had a more noticeable dry tea flavor than in the examples, and was not natural enough. The oolong tea in example 1 has natural and strong fragrance after being fully wetted by water, wherein the oolong tea has better fragrance intensity and fragrance richness after being wetted by 65 ℃ water, particularly 95 ℃ water, and the higher temperature water wetting is more favorable for exciting the tea fragrance.

Example 2

Preparation of aroma condensate A

100kg of oolong tea leaves are put into a reactor, 100kg of RO water with the temperature of 95 +/-2 ℃ is respectively sprayed to uniformly wet the tea leaves, the pressure of aroma recovery equipment is respectively adjusted to 0.011MPa, 0.024MPa and 0.057MPa in a closed mode, the steam temperature is 50 +/-2 ℃, 65 +/-2 ℃ and 85 +/-2 ℃, the steam flow is 95kg/h, and the aroma is recovered for 2h to obtain aroma condensate A.

Preparation of extract B

Preparation of concentrate C

Adding 1000kg of RO water with the temperature of 95 +/-2 ℃ into the extracted tea leaves, leaching for 5min, and cooling to 45 ℃ after the extraction is finished; firstly, 0.03kg of tannase is added, and the enzymolysis reaction is carried out for 1 h; then, 1.5kg of Protease (Protease A2SD, wild) and 0.4kg of pentosanase (Viscozyme L, Novoxil) were added, and the enzymatic reaction was continued for 3 hours. The temperature in the enzymolysis reaction process is controlled to be 45 +/-2 ℃. After the enzymolysis reaction is finished, a filter press is adopted for primary filtration, tea residues are separated to obtain tea soup, the tea soup is sterilized at high temperature by a plate type sterilizer for 30s at 90 ℃, then a disc centrifuge and a filter element filter are adopted for secondary filtration, then cross flow filtration is carried out for fine filtration, the fine filtration liquid is sterilized at high temperature by the plate type sterilizer for 15s at 95 ℃, then a rotary evaporator is used for concentration at 60 +/-2 ℃, and the concentration is adjusted to 20-30 wt% of soluble solid solution (Brix) to obtain concentrated solution C.

Compounding

Mixing the aroma condensate A, the extract B and the concentrated solution C according to the proportion of 1: 1.5: 1, compounding to obtain the high-aroma concentrated tea solution.

Sterilizing the finished product

Sterilizing the compounded high-aroma oolong tea concentrated solution at high temperature by adopting a plate sterilizer, sterilizing at 115 ℃ for 20s, quickly cooling, hot canning at 70 ℃, cooling to room temperature to finally prepare the high-aroma oolong tea concentrated solution, and evaluating the sensitivity of the high-aroma oolong tea concentrated solution, wherein the results are shown in the following table 2.

Comparative example 2

Comparative product 2 was prepared in the same manner as in example 2 except that the aroma recovery apparatus was closed and the pressure was adjusted to 0.005MPa, 0.068MPa and 0.1MPa (atmospheric pressure) respectively at the aroma recovery stage corresponding to steam temperatures of 45 ℃ ± 2 ℃, 90 ± 2 ℃ or 100 ℃ ± 2 ℃, and sensory evaluation was performed, and the results are shown in table 2 below.

Table 2 table of sensory evaluation and evaluation results of the oolong tea concentrate having high fragrance of example 2 and comparative example 2

From the evaluation results in table 2 above, it can be seen that in example 2, after the oolong tea was sufficiently wetted with RO water at 95 ℃, aroma recovery was performed under pressure conditions of 0.011MPa, 0.024MPa, and 0.057MPa, and after the oolong tea was compounded with the flavor extract and the taste concentrate, the tea aroma of the obtained invention was natural and rich, the characteristic flavor of the oolong tea was significant, and high evaluation was obtained. The aroma of the oolong tea is recovered under the pressure conditions of 0.011MPa and 0.057MPa, the aroma is natural and strong, but the aroma intensity is slightly inferior to that of the aroma recovered under the pressure condition of 0.024MPa, and the aroma recovered under the pressure condition of 0.024MPa is optimal. In comparative example 2, the aroma recovery was carried out under normal pressure conditions or under pressure conditions adjusted to 0.068MPa, and the recovered aroma might have a green odor due to an excessively high steam temperature, and the tea leaves were seriously damaged due to an excessively high temperature, and the bitterness of the flavor extract and the concentrated solution was slightly stronger than that of the examples, whereas the tea aroma was natural when the aroma was recovered under 0.005MPa steam conditions, but the strength of the recovered aroma was weak, and had a certain influence on the characteristic aroma and flavor of oolong tea.

Example 3

The procedure of example 1 was completely the same as that of example 1 except that oolong tea leaves were replaced with green tea leaves, and the obtained high-aroma green tea concentrate was evaluated for sensory properties, and the results are shown in table 3 below.

Example 4

The same procedure as in example 1 was carried out except that oolong tea leaves were replaced with black tea leaves in example 1, and the obtained high-aroma black tea concentrate was evaluated for sensory properties, and the results are shown in table 3 below.

Table 3 table of sensory evaluation and evaluation results of the high aroma green tea concentrate of example 3 and the high aroma black tea concentrate of example 4

As can be seen from the evaluation results of table 3 above, in example 3, the tea aroma of the obtained concentrated solution was natural and rich after green tea was sufficiently wetted with water at 25 ℃, 65 ℃ and 95 ℃. The green tea is wetted by water at 25 ℃, the aroma is natural and strong, but the aroma intensity is slightly inferior to the aroma recovered after high-temperature water wetting, the aroma intensity after 95 ℃ water wetting is high, but the natural aroma sense, namely the coordination sense, is slightly inferior to the aroma recovered after low-temperature water wetting, and the aroma recovered after 65 ℃ water wetting is optimal. In example 4, the tea aroma of the concentrate obtained after thoroughly moistening black tea with water at 25 ℃, 65 ℃ and 95 ℃ was natural and strong. The black tea is wetted by water at 25 ℃ and 65 ℃, the fragrance is natural and strong, but the fragrance intensity and the richness are slightly inferior to the fragrance recovered after high-temperature water wetting treatment, and the fragrance and the flavor recovered after the high-temperature water wetting treatment are optimal.

Comparative example 3

In example 1, the oolong tea concentrate obtained was evaluated for sensory properties, except that extract B was not prepared and the tea leaves were sufficiently wetted with 95 ℃ water, in the same manner as in example 1, and the results are shown in Table 4 below.

Comparative example 4

In example 1, the oolong tea concentrate prepared in accordance with the procedure of example 1 was evaluated for sensory properties, except that 0.6kg of pentosanase (ViscozymeL) was not added and the tea leaves were sufficiently moistened with water at 95 ℃.

Table 4 table of sensory evaluation and evaluation results of oolong tea concentrates of comparative examples 3 and 4

As can be seen from the evaluation results in Table 4 above, in comparative example 4, extract B was not prepared, the natural flavor of oolong tea was not partially developed, the sweetness and aftertaste were slightly lower than those of the examples, the aroma was less intense than those of example 1, and the fullness of tea soup and the tea taste were both slightly lower. In comparative example 5, no pentosanase was used in the enzymatic hydrolysis stage, and the sweetness, aftertaste and fullness were slightly lower than those of example 1.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. The preparation method of the tea concentrated solution is characterized by comprising the following aroma extraction steps:

wetting the finished tea leaves with water;

2. A process according to claim 1, wherein the finished tea leaves are moistened with water at a temperature above 65 ℃.

3. The method according to claim 1, wherein the tea leaves have a length of 1 to 5 mm.

4. The method of claim 1, further comprising the steps of: and (3) treating the tea leaves treated by the water vapor according to the weight ratio of the tea leaves to the water of 1: 2-1: 10 extracting to obtain extract B, wherein the extraction temperature is 25-90 ℃, and the extraction time is 1-60 min.

5. The method of claim 4, further comprising the following steps of enzymatic concentration: and (3) mixing the extracted tea leaves according to the weight ratio of the tea leaves to the water of 1: 5-1: 10, leaching at the temperature of 70-95 ℃ for 5-60 min, cooling to 40-50 ℃, adding enzyme for enzymolysis, filtering tea leaves after enzymolysis is finished to obtain tea soup, and concentrating the tea soup until the content of soluble solid solution accounts for 30-50 wt% to obtain concentrated solution C.

6. The method of claim 5, wherein the filtering is performed by: performing primary filtration by using a filter press, then performing centrifugal secondary filtration, and performing cross-flow filtration.

7. The preparation method according to claim 5, wherein the enzymolysis is carried out by the following method: firstly adding tannase for enzymolysis for 10 min-1 h, and then adding protease and pentosanase for enzymolysis for 0.5 h-3 h.

8. The preparation method according to claim 5, further comprising the following compounding step: and mixing the aroma condensate A, the extract B and the concentrated solution C according to the weight ratio of 0.5-2: 1-4: 0.5-1.5 weight ratio.

9. A tea concentrate, characterized in that it is prepared by the preparation method according to any one of claims 1 to 8.