CN102178012B - Method for preparing low-caffeine tea leaves - Google Patents

Abstract

A method for preparing low-caffeine tea leaves. The method is to use tea polyphenols or low-caffeine instant tea powder solution to extract and remove caffeine in fresh tea leaves or dry tea leaves. or instant tea powder, add water to prepare a solution of tea polyphenols or instant tea powder with a concentration of 2% to 20%, put fresh tea leaves or dry tea leaves into the above tea polyphenols or instant tea powder solution to impregnate decaffeline, wherein the fresh tea leaves The weight-volume ratio of the dry tea leaves to the above-mentioned solution is 1:4-1:8, and the weight-volume ratio of the dry tea leaves to the above-mentioned solution is 1:10-1:20, and then the tea leaves are taken out, centrifugally dehydrated, dried, and refined to obtain low-caffeine tea. The invention can make the removal rate of caffeine in tea leaves reach 95%, no loss of tea polyphenols, more than 90% of other active ingredients can be retained, no pollution in the preparation process, and at the same time, the equipment used in the invention is simple, the investment is small, the operation is convenient and convenient Industrialized mass production.

Description

A kind of preparation method of low caffeine tealeaves

technical field

The invention relates to a method for preparing low-caffeine tea leaves, which belongs to the technical field of tea deep processing.

Background technique

Tea has many health functions such as anti-aging, anti-tumor, anti-radiation, anti-fatigue, lowering cholesterol, preventing arteriosclerosis, etc., and is one of the most popular beverages for consumers. However, because tea contains caffeine that excites the brain and the heart, some people with neurasthenia, pregnant women, children, and people with weakened heart function may experience physical discomfort or other side effects after drinking tea with high caffeine content for a long time. Low-caffeine tea can not only meet the needs of these consumer groups for drinking tea, but also can segment the tea market and improve the refinement level of tea processing, which has a good market prospect.

At present, the technology of low-caffeine tea beverage and instant tea powder has matured and entered the stage of industrial production. However, the research on low-caffeine traditional tea is not deep enough, and there is no simple and effective production method. There are mainly the following methods:

1. Hot water extraction method. According to the property that caffeine is easily soluble in hot water, hot water leaching is used to remove caffeine in the initial stage of tea production and complete the greening at the same time. The manufacturing method of patent CN200610097734.1 low-caffeine green tea is the patent about this method. Although this method is relatively simple and easy to implement, the removal rate of caffeine is not high. It can only make the removal rate of caffeine in tea leaves reach about 65%, and the content of caffeine is reduced to about 1% of the dry matter of tea leaves. It is only suitable for producing green tea. Wastewater treatment load is heavy, and

At the same time as caffeine, it also causes a large loss of functional ingredients such as tea polyphenols.

2. The decompression sublimation method is to use the sublimable property of caffeine to reduce the sublimation temperature of caffeine under reduced pressure, thereby selectively removing caffeine from tea leaves. There are few studies on this method, and the results of existing studies show that the removal rate of caffeine is low, only about 50%.

3. Supercritical CO2 _extraction method, this method can effectively remove the caffeine in the tea leaves, so that the content of caffeine in the finished tea is lower than 0.5% of the dry matter of the tea leaves. There are many patents on this method, but the aroma loss of finished tea is serious, and the current supercritical _CO2 extraction equipment is expensive and the processing capacity is small, so it is difficult to apply it in domestic small and medium-sized enterprises.

Contents of the invention

The object of the present invention is to provide a low-caffeine tea that is easy to operate, low in cost, non-polluting and easy to industrialize for the above situations where the caffeine removal rate of the finished tea leaves is not high and the loss of other functional components of the tea leaves is serious. method of preparation.

To achieve the above object, the present invention adopts the following technical solutions:

The preparation method of the low-caffeine tea is to remove the caffeine in fresh tea leaves or dry tea leaves by tea polyphenols or low-caffeine instant tea powder aqueous solution extraction method, and the steps are as follows:

(1) Preparation of tea polyphenols or instant tea powder solution

Use tea polyphenols or instant tea powder with a caffeine content of less than 1.0%, and add water to prepare a solution of tea polyphenols or instant tea powder with a mass fraction of 2% to 20%;

(2) Finishing and decaffeination

Put fresh tea leaves or dry tea leaves into the above tea polyphenols or instant tea powder solution, the treatment requirements are: temperature 90°C-100°C, time 2min-15min, the weight-volume ratio of fresh tea leaves to the above solution is 1:4-1 : 8, dipping and fixing, decaffeination; the weight volume ratio of dry tea leaves to the above solution is 1:10～1:20, steeping, decaffeination;

(3) Dehydration and drying

The extracted tea leaves are taken out, centrifuged or drained, dehydrated, dried, and refined to obtain low-caffeine tea.

In the above steps, when the content of caffeine in the tea polyphenols or instant tea powder solution is greater than 3 mg/ml, use lignocellulose or macroporous resin chromatographic column to remove the caffeine and then recycle it.

The technological conditions of dehydration and drying are: vacuum degree is -0.08Mpa～-0.1Mpa, temperature is below 60°C.

The low-caffeine tea prepared by the present invention can remove 95% of the caffeine in the tea leaves, without loss of tea polyphenols, retain more than 90% of other active ingredients, and the low-caffeine tea leaves still have the style of traditional tea leaves; More importantly, there is no pollution during the preparation process, which ensures the safety of the finished tea. The equipment used in the invention is simple, the investment is small, the operation is convenient and the application range is wide, and it is a new method for producing low-caffeine tea.

Detailed ways

The technical solutions of the present invention and the effects achieved are further described below through specific examples.

Example 1

1) Preparation of tea polyphenol solution: use tea polyphenol with a caffeine content of less than 0.5% and a purity greater than 98% to prepare an aqueous solution of tea polyphenol with a mass fraction of 5%.

2) Deenzyming and decaffeination: put 1Kg of fresh tea leaves into 8L of the above-mentioned tea polyphenol solution for immersion and deenzyming. The treatment conditions are temperature 95° C. and time 4 minutes. Take out the tea leaves after centrifugation or draining. The treated solution is 7.8L. The content of caffeine in the solution is 1.52mg/ml. Add 0.9Kg fresh tea leaves again. The treatment conditions are temperature 100°C and time 5min. After the treatment, the solution The content of caffeine in the solution is 3.21mg/ml (the solution can be recycled after being decafified by lignocellulose or macroporous resin chromatographic column).

3) The above-mentioned extracted tea leaves are centrifugally dehydrated or drained, followed by traditional tea making methods, kneading, drying, and refining to obtain finished tea.

4) In order to illustrate the superiority of this method, deionized water was used instead of tea polyphenol solution, and other conditions were the same as a control treatment. The test results are shown in Table 1

Table 1 Contents of ingredients in tea samples (on a dry basis)

Embodiment 2,

1) Preparation of instant tea powder solution: use instant tea powder with a caffeine content of less than 0.5% to prepare an aqueous solution of instant tea powder with a mass fraction of 15%.

2) Decaffeination: Put 0.5Kg of fried green tea into 10L of the above-mentioned instant tea powder solution, the treatment conditions are temperature 95°C, time 7min, and the tea leaves are taken out after centrifugation or draining. The filtered solution can be used again, and when the content of caffeine in it is greater than 3.0 mg/ml, it can be recycled after being removed from the caffeine through a lignocellulose or macroporous resin chromatographic column.

3) Centrifuge and dehydrate the extracted tea leaves, and dry them at -0.98MPa and 60°C to obtain low-caffeine tea.

4) In order to illustrate the superiority of this method, deionized water was used instead of low-caffeine instant tea powder solution, and other conditions were the same as a control treatment. The test results are shown in Table 2

Table 2 Contents of ingredients in tea samples (on a dry basis)

Embodiment 3,

1) Preparation of tea polyphenol solution: use tea polyphenols with a caffeine content of less than 1.0% and a purity greater than 95% to prepare a tea polyphenol solution with a mass fraction of 15%.

2) Put 0.5Kg of fried green tea into 10L of the above-mentioned instant tea powder solution, the treatment conditions are: temperature 100°C, time 5min.

3) The extracted tea leaves are centrifuged and dehydrated, and dried at -0.98Mpa at 60°C to obtain low-caffeine tea.

4) The solution can be used again after the tea leaves are processed, and when the content of caffeine in it is greater than 3.0 mg/ml, it can be recycled after the caffeine is removed through the lignocellulose or macroporous resin chromatographic column.

5) The treated solution is 9.5 L, and 0.45 Kg of fried green tea is put into it, and treated at 100° C. for 7 minutes.

6) Take out the tea leaves and dehydrate them by centrifugation, and dry them at -0.98Mpa at 60°C to obtain low-caffeine tea 2. The test results are shown in Table 3.

Table 3 Contents of ingredients in tea samples (on a dry basis)

Claims (3)

1. A preparation method for low-caffeine tealeaves, characterized in that: the method is to remove caffeine in fresh tea leaves or dry tea leaves with tea polyphenols or low-caffeine instant tea powder aqueous solution extraction method, and the steps are as follows: (1) Preparation of tea polyphenols or instant tea powder solution Use tea polyphenols or instant tea powder with a caffeine content of less than 1.0%, and add water to prepare a solution of tea polyphenols or instant tea powder with a mass fraction of 2% to 20%; (2) Finishing and decaffeination Put fresh tea leaves or dry tea leaves into the above tea polyphenols or instant tea powder solution, the treatment requirements are: temperature 90°C-100°C, time 2min-15min, the weight-volume ratio of fresh tea leaves to the above solution is 1:4-1 : 8, dipping and finishing, decaffeination; the weight-volume ratio of dry tea leaves to the above solution is 1:10～1:20, steeping, decaffeination, and the units of weight and volume in the weight-volume ratio are Kg and L respectively; (3) Dehydration and drying The extracted tea leaves are taken out, centrifuged or drained, dehydrated, dried, and refined to obtain low-caffeine tea. the 2. The preparation method of low caffeine tealeaves according to claim 1 is characterized in that: when the caffeine content in tea polyphenols or instant tea powder solution is greater than 3mg/ml, remove wherein with lignocellulose or macroporous resin chromatographic column After the caffeine is recycled. the 3. The method for preparing low-caffeine tea leaves according to claim 1, characterized in that: the process conditions for dehydration and drying are as follows: the degree of vacuum is -0.08MPa to -0.1MPa, and the temperature is below 60°C. the