CN1262047A - Low-temp vacuum method for drying tea leaves - Google Patents

Abstract

A low-temp vacuum drying method for tea includes such steps as predrying tea leaves until its water content is lower than 20%, freezing, vaccumizing at temp lower than O deg.C, dewatering by sublimation, and condensating to capture water vapour until the tea leaves are dried to meet requirement. Its advantages are no variation in colour and shape, no loss of nutrients, and long storage period of tea (up to more than one year).

Description

The low-temp vacuum method for drying of tealeaves

The present invention relates to a kind of drying means of tealeaves.

Tealeaves is one of the three big beverages in the world, also be called the beverage of 21st century, various countries, the world today drink just flourish the popularization of tealeaves, especially in recent years about green tea, blue or green tea just deepens continuously to healthy and helpful research, the well-known tea of China has been extensively understanding of countries in the world consumer institute, but, the subject matter that processing of puzzlement Tea Production and storage at present preserved is how to reduce the water content of tealeaves, China standard GB/T14456-93, requirement is GB/8304-87 to the tealeaves water content≤7%, and the too high current production that is still of tealeaves water content is difficult to preserve and underproof principal element on production.

At present, the drying in the whole nation and even the whole world Tea Production process is still used the hyperthermia drying method, but the hyperthermia drying method has following shortcoming:

1. difficult control of temperature in producing easily causes degree of drying not enough, or Yin Wendu is too high, overlong time makes tealeaves produce the smell of burning;

2. hyperthermia drying easily makes the amino acid in the tealeaves change, and its nutrition is reduced;

3. easily produce harmful substance in the hyperthermia drying process;

4. hyperthermia drying easily makes the tealeaves color change, as makes tealeaves by green flavescence etc.;

5. it is impaired that hyperthermia drying makes the tealeaves profile, and producing fannings influences outward appearance;

6. the tealeaves storage life of hyperthermia drying, shelf-life lack, generally in 1 year.

The objective of the invention is: the low-temp vacuum method for drying that a kind of tealeaves is provided, this method can guarantee under the prerequisite that the tealeaves color is constant, profile is constant, nutrition is constant, moisture content in the tealeaves is reduced to below 6%, minimumly reduce to 0.3%, thereby make the tealeaves can long preservation, generally can reach more than 1 year.

Technical scheme of the present invention is: a kind of low-temp vacuum method for drying of tealeaves comprises the following steps:

(1) tealeaves is freezed, and make tealeaves dehydration distillation being lower than under 0 ℃ and the condition that vacuumizes;

(2) catch the steam of distillation with the method for condensation, until tea-drying to needed degree.

The further technical scheme of the present invention is: a kind of low-temp vacuum method for drying of tealeaves, comprise the following steps: that (1) carry out pre-dried with tealeaves, and the moisture content in the tealeaves is reduced to below 20%;

(2) tealeaves is freezed, and make tealeaves dehydration distillation being lower than under 0 ℃ and the condition that vacuumizes;

(3) catch the steam of distillation with the method for condensation, until tea-drying to needed degree.

Advantage of the present invention is:

1. the present invention can make the moisture content in the tealeaves drop to below 6%, minimumly reaches 0.3%;

2. because the present invention carries out, can not destroy the various nutritions in the tealeaves under the cryogenic vacuum condition;

3. the present invention can guarantee that the color of tealeaves is constant;

4. because the present invention need not to stir-fry, can keep the profile of tealeaves constant;

5. because the water content of the tealeaves that the present invention handles is lower, help the long preservation of tealeaves, generally can reach more than 1 year.

The present invention is further illustrated below in conjunction with embodiment;

Embodiment: a kind of low-temp vacuum method for drying of tealeaves comprises the following steps:

(1) tealeaves is carried out pre-dried, the moisture content in the tealeaves is reduced to below 20%;

(2) tealeaves is freezed, and make tealeaves dehydration distillation being lower than under 0 ℃ and the condition that vacuumizes;

(3) catch the steam of distillation with the method for condensation, until tea-drying to needed degree.

The present invention is the revolution on the tea-drying treatment process, changed original traditional handicraft that stir-fries of smoking, the profile and the color that can keep tealeaves keep the various nutritions in the tealeaves, and main is the shelf-life and the storage life that can prolong tealeaves greatly.

Claims (2)

1. the low-temp vacuum method for drying of a tealeaves comprises the following steps:

(1) tealeaves is freezed, and make tealeaves dehydration distillation being lower than under 0 ℃ and the condition that vacuumizes;

(2) catch the steam of distillation with the method for condensation, until tea-drying to needed degree.

2. the low-temp vacuum method for drying of tealeaves according to claim 1, it is characterized in that: described tealeaves can carry out predrying before freezing, and made the water content of tealeaves be lower than 20%.