CN1843144A - Method for eliminating caffeine from tea leaf - Google Patents

Abstract

The invention discloses a method for removing caffeine from tea, which comprises the following steps: (1) freezing deionized water to 0 deg C to obtain ice-water mixture, (2) charging green tea into ice-water mixture, placing in vacuum drying oven, vacuum-pumping for digestion, (3) filtering the leach to obtain high purity caffeine filtrate and filtering deposit of high purity tea polyphenol with caffeine removed.

Description

The method of eliminating caffeine from tealeaves

Technical field

The present invention relates to the method for eliminating caffeine from tealeaves.

Background technology

Because the medicinal efficacy and the health care of Tea Polyphenols or catechin more and more are subjected to people's attention, the technological process development in recent years of extracting Tea Polyphenols or catechin from tealeaves is very fast, but be difficult in Tea Polyphenols that obtains or the catechin product simultaneously caffeine be removed, and the content size of caffeine in product is very big to the application influence of product.At present industrial method for removal caffeine from Tea Polyphenols or catechin product mainly contains following several:

1. extract from tea extract with chlorides such as chloroform or carrene and remove caffeine, clearance is higher, but because chloride is poisonous, causes product to be affected as medicinal or health products raw material;

2. the extract with acid solution or weak lye washing ethyl acetate removes caffeine, this method acid solution or weak lye consumption are big, yield influence to product is bigger, its commercial Application is restricted, simultaneously again because organic solvent residue causes Tea Polyphenols or catechin to be subjected to certain confinement in the use of medicinal or health products raw material;

3. with ionizable metal salt such as Ca ²⁺, Al ³⁺, Zn ²⁺Deng removing the complexing Tea Polyphenols, change molten sediment with acid again, the extraction of ethyl acetate removes caffeine, should be similar to the 2nd kind of method, because a large amount of ionizable metal salt and organic solvents of using cause Tea Polyphenols or catechin to be severely limited in the use of medicinal or health products raw material;

4. use supercritical CO ₂Caffeine in the extraction extraction tealeaves or the caffeine technology in the Tea Polyphenols product, complicated operation, equipment investment is big, and the production cost height is difficult in the industrial production promote.

Summary of the invention

The purpose of this invention is to provide a kind of easy and simple to handlely, cost is low, and is pollution-free, be easy to industrialized from tealeaves the method for eliminating caffeine.

In order to achieve the above object, the present invention has following two kinds of technical solutions.

Scheme 1: frozen water extraction

The method of eliminating caffeine from tealeaves, its step is as follows:

1) deionized water frozen cause 0 ℃, mixture of ice and water;

2) by solid-to-liquid ratio, every 1g green tea adds 15～25ml mixture of ice and water in container, places vacuum drying chamber then, and suction is to-0.1, lixiviate;

3) filter leaching liquor, obtain high-purity caffeine filtrate, filter residue is the high-purity tea polypenols tealeaves of caffein-free.

Scheme 2: frozen water adjust pH extraction

The method of eliminating caffeine from tealeaves, its step is as follows:

1) the pH value with deionized water transfers to 3.0～4.00, freezes to cause 0 ℃, gets mixture of ice and water;

2) by solid-to-liquid ratio, every 1g green tea adds 15～25ml mixture of ice and water in container, places vacuum drying chamber then, and suction is to-0.1, lixiviate;

3) filter leaching liquor, obtain high-purity caffeine filtrate, filter residue is the high-purity tea polypenols tealeaves of caffein-free.

The present invention adopts the negative pressure low temperature method that caffeine is separated with Tea Polyphenols, mainly utilize in negative pressure low temperature system, the different solubility of caffeine and Tea Polyphenols again because the adhesion of caffeine and Tea Polyphenols and tealeaves tissue there are differences, causes the two can reach certain separation simultaneously.In the separated filtrate of the present invention, the purity of caffeine is up to 1.8g/L, and filter residue is the high-purity tea polypenols tealeaves of caffein-free.

If the pH value is taken in caffeine and Tea Polyphenols solubility influence factor, in pH value 3.0～4.0, caffeine is that the form with salt exists basically, solubility in frozen water strengthens, and Tea Polyphenols mainly exists with molecular state at this moment, solubility in frozen water is less, and character is more stable.According to the purposes of product, can select whether to use sour adjust pH, the acid that adjust pH is used can be hydrochloric acid, acetic acid or citric acid; Use for the product that can bring acid into, can obtain corresponding effect by prolongation extraction time, increase liquid-solid ratio.In above-mentioned two schemes, extraction time at least 1.5 hours.

The present invention is simple to operation, cost is low, small investment, pollution-free, Product Green safety, be easy to industrialization, compare with present production technology, not only need not to use in a large number environmental pollution and harmful production reagent, as chloride, ethyl acetate, ionizable metal salt etc., but also can obtain green natural high-purity caffeine product cheaply, can effectively alleviate in the green tea beverage difficult problem that occurs insoluble matter because of caffeine and Tea Polyphenols complexing.The green safety caffeine that separates is suitable for the production application of food, medicine, health products.

The instantiation mode

Example 1

With deionized water, place refrigerator-freezer to freeze and cause 0 ℃, get mixture of ice and water; 3 parts, every portion 100g green tea is placed plastic beaker respectively, by solid-to-liquid ratio, every 1g green tea adds the 20ml mixture of ice and water in container, be put in vacuum drying chamber, suction is distinguished lixiviate 1.5h, 2.0h, 2.5h to-0.1, take out leaching device, filter, obtain the filtrate of high-purity caffeine, filter residue is the high-purity tea polypenols tealeaves of caffein-free.Composition result of variations such as following table 1:

Table 1

Example 2

With hydrochloric acid the pH value of deionized water is transferred to 3.0, places refrigerator-freezer to freeze and cause 0 ℃, mixture of ice and water; 3 parts, every portion 100g green tea is placed plastic beaker respectively, by solid-to-liquid ratio, every 1g green tea adds the 25ml mixture of ice and water in container, be put in vacuum drying chamber, suction is distinguished lixiviate 1.5h, 2.0h, 2.5h to-0.1, take out leaching device, filter, obtain the filtrate of high-purity caffeine, filter residue is the high-purity tea polypenols tealeaves of caffein-free.Composition result of variations such as following table 2:

Table 2

Claims (2)

1. the method for eliminating caffeine from tealeaves, its step is as follows:

1) deionized water frozen cause 0 ℃, mixture of ice and water;

2) by solid-to-liquid ratio, every 1g green tea adds 15～25ml mixture of ice and water in container, places vacuum drying chamber then, and suction is to-0.1, lixiviate;

3) filter leaching liquor, obtain high-purity caffeine filtrate, filter residue is the high-purity tea polypenols tealeaves of caffein-free.

2. the method for eliminating caffeine from tealeaves, its step is as follows:

1) the pH value with deionized water transfers to 3.0～4.0, freezes to cause 0 ℃, gets mixture of ice and water;

2) by solid-to-liquid ratio, every 1g green tea adds 15～25ml mixture of ice and water in container, places vacuum drying chamber then, and suction is to-0.1, lixiviate;

3) filter leaching liquor, obtain high-purity caffeine filtrate, filter residue is the high-purity tea polypenols tealeaves of caffein-free.