CN101874534A - Method of applying ultrasonic technology to the preparation of tea extract liquid film concentration - Google Patents

Abstract

The invention relates to a method for the concentrated preparation of a tea extract liquid film, and aims to provide a method in which ultrasonic technology is applied to the concentrated preparation of a tea extract liquid film. The method includes: (1) removing slag from the tea extract through gauze, and then pre-filtering through a sieve; (2) filtering and clarifying the tea juice through a membrane with a molecular weight of 50,000 to 250,000, and at the same time ultrasonically treating the tea juice. Control within 40°C; (3) Concentrate through the concentrated membrane, and at the same time ultrasonically treat the tea juice, the temperature is controlled within 40°C; when the flux of the membrane tends to zero, the concentrated tea juice is obtained. The invention applies ultrasonic technology to the preparation of tea extract liquid membrane concentration, applies the mechanical and cavitation effects of ultrasonic waves, and in the clarification of membrane ultrafiltration, while ensuring the clarification effect of tea juice, it can improve the preservation rate of active ingredients and membrane flux , improve the efficiency of filtration. In membrane concentration, the membrane flux of the concentrated membrane is increased to increase the concentration of the concentrated juice.

Description

Method of applying ultrasonic technology to the preparation of tea extract liquid film concentration

technical field

The invention relates to a method for the concentrated preparation of a tea extract liquid film, in particular to a method in which ultrasonic technology is applied to the concentrated preparation of a tea extract liquid film.

technical background

The production of concentrated tea juice has traditionally used the traditional thermal concentration process at home and abroad. However, because this method involves phase change, it not only consumes a lot of energy, but also tends to cause loss or deterioration of heat-sensitive substances due to oxidation and polymerization, making the product poor in cold solubility. , the tea fragrance is weak, the tea flavor loss is large, and the aroma is poor. In order to change this situation, the tea concentrate processing technology based on membrane technology has been systematically studied.

However, in the process of purely using membrane technology to process tea concentrate, a large amount of active ingredients will be lost during the filtration and clarification process, and the filtration efficiency needs to be improved. At the same time, the content concentration of the concentrated solution obtained by membrane technology is relatively low, because with the increase of the content of the concentrated solution, the macromolecular polymer body in the extract will also increase, and the pollution of the membrane will increase, thus speeding up the degradation of the membrane. Damage, resulting in a decrease in membrane flux, and the content of the liquid cannot be further increased.

Therefore, if the loss of active ingredients of tea juice can be reduced in the preparation of tea extract liquid membrane concentration, and the concentration and preparation efficiency of concentrated juice can be improved, then this will improve the utilization rate of tea resources, increase the content of the concentrated solution, and improve the preparation efficiency. efficiency.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a method for applying ultrasonic technology to the preparation of tea extract liquid film concentration.

Ultrasound refers to mechanical waves with a frequency of 20-106 kHz, which has the characteristics of high frequency, short wavelength, and strong penetrating power. When it propagates in the medium, it can produce cavitation and a series of special effects, such as stirring, dispersing into fog, agglomeration, impact crushing and fatigue damage, heating, promoting oxidation and reduction, and promoting the polymerization or depolymerization of polymer substances, etc. .

There are two applications of ultrasound in membrane technology: one is to use high-frequency and low-amplitude ultrasound to detect the pollution and cleaning status of the membrane surface online. The present invention utilizes ultrasound to strengthen the membrane separation process to increase membrane flux.

In order to solve technical problems, the method for applying ultrasonic technology to the preparation of tea extract liquid membrane concentration provided by the invention comprises steps:

(1) The tea extract is removed through gauze, and then pre-filtered through a sieve;

(2) The tea juice treated in the step (1) is clarified by membrane filtration with a molecular weight of 50000～250000, and at the same time, the tea juice is treated with an ultrasonic wave with a frequency of 20～50kHz and a power of 110～440W, and the temperature control of the tea juice Within 40°C;

(3) Concentrating the treated tea juice in step (2) through a concentrated membrane, and simultaneously adding ultrasonic treatment with a frequency of 20 to 50 kHz and a power of 110 to 440 W to the tea juice, so that the temperature of the tea juice is controlled within 40 ° C; When the membrane flux tends to zero, the concentrated tea juice is obtained.

In the present invention, the tea can be various types of teas such as green tea, black tea, and oolong tea.

In the present invention, the membrane for filtration and clarification may be an ultrafiltration membrane, a microfiltration membrane, a ceramic membrane, and the like.

In the present invention, the concentration membrane may be reverse osmosis membrane, nanofiltration membrane and the like.

The beneficial effects of the present invention are:

Applying ultrasonic technology to the preparation of tea extract liquid membrane concentration, using the mechanical and cavitation effects of ultrasonic waves, in the clarification of membrane ultrafiltration, while ensuring the clarification effect of tea juice, it can improve the preservation rate of active ingredients and membrane flux, and improve Filtration efficiency. In membrane concentration, the membrane flux of the concentrated membrane is increased to increase the concentration of the concentrated juice.

Detailed ways

The present invention will be further described below by specific examples of the present invention, but the examples are not limitations of the present invention.

Example 1:

(1) Add green crushed tea into water at 90°C according to the ratio of tea to water 1:20, extract for 10 minutes, remove residue with gauze, and pre-filter through a sieve.

(2) passing the filtrate in the step (1) through an ultrafiltration membrane with a molecular weight of 100000, and simultaneously adding ultrasonic treatment with a frequency of 27.5KHz and a power of 330W to the tea juice; the temperature of the tea juice is controlled within 40°C.

Results During the ultrafiltration process, the membrane flux increased by 28% to 33%, and the contents of tea polyphenols, amino acids, and caffeine in the obtained ultrafiltrate increased by 6.8%, 3.0%, and 5.0%, respectively, while protein, pectin The content of other macromolecular substances changes little.

(3) Concentrate the ultrafiltrate treated by step (2) through a reverse osmosis membrane, and simultaneously add ultrasonic treatment with a frequency of 27.5KHz and a power of 330W to the ultrafiltrate, and control the temperature of the tea juice within 40°C; The tea concentrate is ready when the flux tends to zero.

Results During the reverse osmosis process, the membrane flux increased by 21% to 28%, and the concentration of the obtained concentrated juice increased by 15%.

Example 2:

(1) Add green crushed tea into water at 90°C according to the ratio of tea to water 1:20, extract for 10 minutes, remove residue with gauze, and pre-filter through a sieve.

(2) passing the filtrate in the step (1) through an ultrafiltration membrane with a molecular weight of 50,000, and simultaneously adding ultrasonic treatment with a frequency of 27.5KHz and a power of 330W to the tea juice; the temperature of the tea juice is controlled within 40°C.

Results During the ultrafiltration process, the membrane flux increased by 40% to 250%, and the contents of tea polyphenols, amino acids, and caffeine in the obtained ultrafiltrate increased by 10.9%, 6.0%, and 3.1%, respectively, while protein, pectin The content of other macromolecular substances changes little.

(3) Concentrate the ultrafiltrate treated by step (2) through a reverse osmosis membrane, and simultaneously add ultrasonic treatment with a frequency of 27.5KHz and a power of 330W to the ultrafiltrate, and control the temperature of the tea juice within 40°C; The tea concentrate is ready when the flux tends to zero.

Results During the reverse osmosis process, the membrane flux increased by 15% to 22%, and the concentration of the obtained concentrated juice increased by 18%.

Example 3:

(1) use black tea as raw material;

(2) The membrane that is filtered and clarified is a microfiltration membrane, the molecular weight is 250,000, the frequency of the ultrasonic wave is 50kHz, and the power is 440W;

(3) The concentration membrane uses a nanofiltration membrane, the frequency of the ultrasonic wave is 50kHz, and the power is 440W.

All the other processing conditions are identical with embodiment 1.

Example 4:

(1) use oolong tea as raw material;

(2) The membrane that is filtered and clarified is a ceramic membrane, the molecular weight is 50000, the frequency of the ultrasonic wave is 20kHz, and the power is 110W;

(3) A nanofiltration membrane is used for the concentrated membrane, the frequency of the ultrasonic waves is 20 kHz, and the power is 110 W.

All the other processing conditions are identical with embodiment 1.

It should be understood that: the above-mentioned examples are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the invention.

Claims (4)

1. A method of applying ultrasonic technology to the preparation of tea extract liquid film concentration, comprising steps: (1) The tea extract is removed through gauze, and then pre-filtered through a sieve; (2) The tea juice treated in the step (1) is clarified by membrane filtration with a molecular weight of 50000～250000, and at the same time, the tea juice is treated with an ultrasonic wave with a frequency of 20～50kHz and a power of 110～440W, and the temperature control of the tea juice Within 40°C; (3) Concentrating the treated tea juice in step (2) through a concentrated membrane, and simultaneously adding ultrasonic treatment with a frequency of 20 to 50 kHz and a power of 110 to 440 W to the tea juice, so that the temperature of the tea juice is controlled within 40 ° C; When the membrane flux tends to zero, the concentrated tea juice is obtained. 2. The method according to claim 1, wherein the tea is any one of green tea, black tea or oolong tea. 3. The method according to claim 1, characterized in that, the membrane used for filtration and clarification in step (2) is any one of ultrafiltration membrane, microfiltration membrane or ceramic membrane. 4. The method according to claim 1, characterized in that, the concentrated membrane used in step (3) is a reverse osmosis membrane or a nanofiltration membrane.