JPS62272940A - Method for heat-treating tea leaf and device therefor - Google Patents

Abstract

PURPOSE:To stop activity of oxidase and to contrive to improve qualities such as color, taste, etc., by thinly spreading raw tea leaves or steamed tea leaves on an endless conveyor belt and passing the conveyor through a heating chamber heated to a specific temperature. CONSTITUTION:Raw tea leaves or steamed raw tea leaves are thinly spread on an endless conveyor belt and passed through a heating chamber heated at 150-500 deg.C. A device constructed as in the following is used in order to heat-treat the tea leaves in this way. Namely, the device consists of (1) an endless conveyor belt 1 made of metal equipped with a tea leaf receiver port (hopper 10) at one end and an outlet (port connected to a transporting device 9) at the other end, respectively, (2) heaters 2 and 4 set at the top and the bottom of the endless conveyor belt 1 made of metal and (3) a heating chamber wherein the upper parts and the lower parts of the heaters 2 and 4 are surrounded by a heat insulating material 6, wherein the temperature in the heating chamber can be set at high temperature of about 150-500 deg.C and the traveling speed of the conveyor belt 1 can be regulated (controlled by a variable speed motor 8).

Description

Detailed Description of the Invention 3. Detailed Description of the Invention A) Field of Industrial Application This invention is directed to the step of stopping the activity of oxidizing enzymes in tea leaves, which is the first step in the tea manufacturing process.

0) Conventional technology Most green tea processing involves steaming in the first heat treatment process.In some cases, instead of steaming, there is a method of roasting the leaves in a roasting machine made of a thick iron plate, but only a few It has only been done in English.

8) Problems that the invention aims to solve The steam heat treatment process requires the installation of a boiler that generates steam, which increases equipment costs, and the leaked steam falls as water droplets, causing damage to the surroundings of the machine. Tea leaves tend to become unclean, and water droplets adhere to the steamed tea leaves, reducing the efficiency of the next step, the rough rolling step.

In addition, in the roasting process, uneven heating tends to occur where the tea leaves touch the iron plate and where they do not, and there remain areas where the activity of oxidizing enzymes cannot be stopped. Moreover, the working time is very long and the efficiency is low.

This invention aims to stop the activation of oxidizing enzymes by directly exposing tea leaves to a high temperature atmosphere without using steam or roasting them on an iron plate like in a pastry machine, and to stop the activation of steam-treated tea leaves. The purpose of this project is to eliminate uneven steaming by further heating the tea leaves, and to improve the quality of the aroma, color, etc. that results from subjecting the tea leaves to high temperatures that cannot be obtained by steaming, and to develop a device for this purpose.

2) Means for solving the problem This invention will be explained based on the drawings. 1 is a metal endless transport belt for spreading the tea leaves thinly and sending them, 2 is a lower heater using a gas burner, and 3 is a large shield to prevent the burner's flame from coming into contact with Ir.

4 is an upper heater using an infrared burner, and 5 is a reflecting plate that reflects heat onto the transport zone 1. Reference numeral 8 denotes a heat insulating material, which constitutes a heating chamber that is tm wide around the heater 2.4. 7 is a damper that adjusts the ventilation of the heating chamber, 8 is a variable speed motor that drives the transport belt, 9 is a transporter connected to the delivery end, 10 is a hopper provided at the tea leaf receiving port, and 11 is a paddle for flattening the tea leaves. 12 is a steamer, and 13 is a steam exhaust fan. 12
．． No. 13 is unnecessary when heat-treating iii occipital leaves. The heater 4 may be an electric heater, a heat exchange pipe through which heavy oil combustion gas, etc. passes, or the like.

(Act) First, the heater 2.4 heats the inside of the heating chamber surrounded by the heat insulating material 6 to an atmosphere of 150°C to 500°C. The fresh leaves put into the hopper 10 at the intake port are passed through the taming device 1.
11 onto the metallic transport band 1, transported into a heating chamber, and directly exposed to a high temperature atmosphere. The activity of the oxidase in fresh leaves can be stopped when exposed to a temperature of 100°C for about 30 seconds, so the speed of the transport zone can be adjusted by adjusting the driving motor 8, and the time it takes for fresh leaves to pass through the heating chamber can be adjusted. The degree of heating can be adjusted as appropriate. By adjusting the damper 7 provided in the heating chamber, the bad odor generated from the heated fresh leaves can be efficiently removed.

A similar action is applied when heating the tea leaves after steaming, but the exhaust fan 13 installed in the receiving hopper
It is better to suck the steam generated from the fresh leaves after steaming and then send it to the heating chamber.

f) Effects of the invention The main effects of directly heating S are that, compared to using steam heat, it is economical because a boiler is not required to generate steam, and water droplets due to condensation of leaked steam are It is clean because the surrounding area does not get wet.

Compared to leaf roasting machines, it has a simpler structure and is more efficient as it can evenly heat a large amount of fresh leaves.

If this heat treatment is applied to tea leaves after steaming, for tea leaves that require a short heating time, such as wakamushi, this heat treatment will eliminate uneven steaming and will maintain a fresh green color by completely killing oxidizing enzymes. I can do it.

Furthermore, for products that require a long steaming time, such as deep steaming, steaming W can be removed by this heat treatment, which can be expected to shorten the time for the rough rolling process in the subsequent process.

Furthermore, by exposing the tea leaves to high temperatures that cannot be obtained with steam, the endogenous components of the tea leaves can be changed and quality such as color and taste can be improved. In addition, since the tea leaves can be softened by this high heat, the edges of the tea leaves can be rubbed very easily, thus increasing the drying efficiency and improving the shape of the product.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the apparatus of the present invention. 1...... Endless transport belt 2.4... Heating* (WL) 6...
...Insulation material

Claims (1)

[Claims] 1) Fresh tea leaves are spread thinly on an endless transport zone and heated at 150°C to 50°C.
A method of heat treatment of tea leaves by passing them through a heating chamber heated to 0°C. 2) Spread the steam-treated tea leaves thinly on an endless transport belt,
A method of heat treatment of tea leaves by passing them through a heating chamber heated to 50°C to 500°C. 3) In a device consisting of a metal endless transport belt with a tea leaf inlet at one end and a tea leaf outlet at the other end, a heating device is provided on the lower and upper surfaces of the metal endless transport belt, and the top and bottom of the heating device are This tea leaf heat treatment device has a heating chamber surrounded by a heat insulating material, the temperature inside the heating chamber can be set to a high temperature of about 150°C to 500°C, and the feeding speed of the transport zone can be adjusted.