JP3157504B1 - Method for producing versatile tea - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To incorporate a sterilization process into a tea manufacturing process to simplify the process, and to be taken out as a product in a powdered state suitable for tea for various purposes, and further to a certain degree for drying purposes. Provided is a method for producing tea. SOLUTION: Steamed tea leaves are dried, and then the steamed tea leaves are dried to obtain an intermediate raw material M having a predetermined moisture content.
Thereafter, the intermediate raw material M was supplied to the screw extruder 1, and the intermediate raw material M was subjected to a heat treatment while passing through the screw extruder 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing versatile tea which is suitable for blending tea leaves such as Japanese tea into confectionery and the like other than drinking.

[0002]

2. Description of the Related Art Tea leaves such as Japanese tea are poured into hot water for drinking. In recent years, more and more cases have been used in which finely ground powdered tea is blended with confectionery, ice cream and the like. . Here, when pouring hot water and drinking, it is sterilized by the heat of hot water, but if it is used as it is near normal temperature in confectionery etc., there is no sanitary difficulty if nothing is done, and sterilization processing is important Has become. In recent years, with the boom in tea, the number of tea leaves used in various food fields such as confectionery and ice cream (herein referred to as multipurpose tea) has increased. There is a need to reduce the number. As a disinfection method, a method using microwaves or steam has been known.
Sterilization method using pressurized unsaturated steam or saturated steam on a finished tea leaf having a water content of about 4% (Japanese Patent Laid-Open No. 10-1086)
No. 21, etc.), and a sterilization method of irradiating the finished tea leaves with microwaves.

[0003]

However, since the above-mentioned sterilization method is intended for low-moisture tea leaves which are difficult to sterilize, the discoloration and fragrance of the product are liable to accompany, and it is difficult to sterilize the product with high strength. In addition, in order to process the finished product again, for example, a processing step different from the tea manufacturing step in which the finished product was made through the rough kneading step → kneading step → medium kneading step → fine kneading step → drying step in the green tea manufacturing method, Processing equipment was required. Equipment costs increased, and product costs increased due to increased working hours. In addition, since tea for many uses is often used in the final pulverized form, a product that has been pulverized to some extent is required, but in order to meet this demand, further processing steps and processing equipment are required. Was needed.

[0004] The present invention solves the above problems,
Providing a method for producing versatile tea, which can simplify the process by incorporating the sterilization process into the tea-making process, can be taken out as a product in a powdered state suitable for versatile tea, and can be dried to some extent. The purpose is to do.

[0005]

In order to achieve the above-mentioned object, the gist of the invention according to claim 1 is to steam the plucked tea leaves, and then to process the steamed and heat-treated tea leaves at least in a coarse kneading step and a kneading step. After the middle rubbing process, the moisture percentage of tea leaves is 10-3
And intermediate material to fall in the range of 0%, after which the intermediate material is fed to a twin-type screw extruder, 該Su
The screw of the screw extruder plays a major role in feeding
A feed pattern part consisting of a thread forming part and a screw
A stirring pattern formed and meshed with the feed
Make the powder of the intermediate raw material denser than the screw pitch of the pattern part.
Crushing and atomization pattern section
The tea leaves as raw materials are discharged at the screw feed pattern
Transported in the direction
Is performed and the tea leaves are finely crushed in the crushing pattern portion.
And further while passing through the screw extruder.
Heat treatment is applied to the intermediate raw material by setting the temperature of the inner wall portion of the heating cylinder related to the screw extruder to 100 to 200 ° C.
In the manufacturing method of the multi-applications tea, characterized in that it is.
Here, the “intermediate raw material” includes a finished product that has been commercialized.
"The temperature of the inner wall portion of the cylinder is set to 100 to 200C"
It is preferable that the temperature be in the range of 100 to 200 ° C. over the entire inner wall portion of the cylinder.

[0006] As in the first aspect of the present invention, when the intermediate material is passed through a screw extruder, the kneading action of the screw extruder causes the pulverization and atomization of the intermediate material to proceed. In particular, two
With a screw extruder of the shaft type, one screw
The thread of the screw meshes with the groove of the other screw and crushes
Increase productivity not only by improving power but also by forced extrusion
Also improve. In addition, the screw of the screw extruder
Is a feed putter consisting of a thread forming part that plays a large role in feeding
A stirrer formed by forming a flange on the screw
The pitch of the screw in the stirring pattern and the feed pattern
Pulverizing putter for pulverizing and atomizing intermediate raw materials
And the intermediate raw material is a screw,
Is transported toward the outlet at the feed pattern section of the
A certain amount of stagnation and agitation are performed in the
Proceed. Furthermore, the tea leaves are finely crushed in the crushing pattern part.
To obtain a crushed form of versatile tea
You. Further, if the cylinder, the screw, and the like are heated by the heating means of the screw extruder, heat sterilization and deaeration drying at the discharge port can be performed. Thus, the process can be simplified by inserting an operation process using the present screw extruder instead of the fine rubbing process of the conventional green tea manufacturing method.
When an intermediate raw material having a water content within the range of 10 to 30% is used, the drying step after the product is taken out can be promptly performed, and in some cases, can be omitted. When the temperature of the inner wall portion of the cylinder is set to 100 to 200 ° C., discoloration of the product and deterioration of the fragrance can be suppressed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a method for producing multipurpose tea according to the present invention will be described in detail. 1 to 3 show an embodiment of a method for producing tea for multi-purpose use according to the present invention. FIG. 1 is a schematic cross-sectional view of a screw extruder used for this, FIG. 2 is a front view of the screw of FIG. FIG. 2 shows a partial perspective view of the screw.

The method for producing multipurpose tea of the present invention is carried out, for example, as follows. First, the plucked tea leaves are steamed, and then the steam-heat treated tea leaves are dried to produce an intermediate raw material M having a predetermined moisture content. The intermediate material M
Is made through a rough kneading step, a kneading step, and a middle kneading step in a known sencha manufacturing method. After the picked tea leaves are heated by steam at about 100 ° C. in the steaming step to complete the steaming heat treatment, the tea leaves are cooled in a cooling step with air and moisture on the tea leaf surface is removed. Then, in the next rough rubbing step, the water content is dried to about 50% by rubbing and hot air. The water content refers to the weight% of the water relative to the total weight of the tea leaf (including the intermediate raw material M and the multipurpose tea) including the water. Then knead in the kneading process,
Then, in the middle rubbing step, a product having a further reduced moisture content is produced by rubbing and hot air, and this is used as the intermediate raw material M of the present invention. Finish the middle rubbing process at least and reduce the water content to 10-30%
It is more preferable to set the intermediate raw material M in the range described above because a drying step (described later) is not required or is performed promptly. If necessary, add a fine rubbing step after the middle rubbing step of the sencha process to reduce the moisture content to less than 20% (usually about 12 to 13%)
The raw material M may be used as the intermediate raw material M. This is even more preferable, since the drying step can be surely omitted after passing through the screw extruder 1 of the present invention.

Here, in the method for producing green tea, the steaming step,
The intermediate raw material M after the cooling step, the coarse kneading step, the kneading step, and the middle kneading step is appropriately kneaded in the fine kneading step and dried to about 12% of moisture by heating on a metal plate. Although hot water is used to dry the water to about 4% to produce needle-like or fragment-like finished products, it is difficult to reduce the viable count of tea leaves in the process. Although it undergoes strong sterilization in the steaming process and decreases to about 300 pieces / g, it increases in the cooling and rough rubbing process, is almost constant in the kneading, medium rubbing, and fine rubbing processes, and slightly decreases in the drying process. Generally shown. The temperature of the tea leaves from the cooling step to the fine kneading step is in the range from room temperature to 40 ° C., and is about 70 ° C. in the drying step. It has a bactericidal effect in the drying process, but its ability is 1/10 of the viable count of tea leaves after fine or medium rubbing.
It is only reduced to about 1/100. Therefore, in order to always control the number of viable bacteria in the finished product of the sencha process, it is necessary to always control the number of viable bacteria before drying.
It was difficult with the traditional green tea manufacturing method.

[0010] In the Tencha method of producing the unpolished raw material of matcha, the picked tea leaves are heated in a steaming process, spread thinly on a belt conveyor in a cooling and dispersing process, and sent into a Tencha machine. After the tea leaves are dried by hot air at 150 to 180 ° C, the temperature is gradually lowered, and the tea leaves are discharged from the tea machine. After the stem and leaves are separated, a fragmentary finished product is produced by the same drying process as the sencha method. Is done. The number of viable bacteria by the Tencha manufacturing method is subject to strong heat sterilization in the process using the Tencha machine.
Moreover, since the tea leaves discharged from the tea machine have been reduced to a moisture content close to that of the finished product, the viable cell count of the finished product is generally kept low. However, the drying efficiency per plant facility area is remarkably low compared to the sencha manufacturing method, and a facility having several times the area is required to process the same raw tea leaves. Further, it is disadvantageous that the machinery and facilities are expensive and the production cost is very high.

Therefore, in the present invention, while utilizing the high drying ability of the sencha process, a part of the sencha process is replaced to control the number of viable bacteria at all times, and the crushing process is carried out so as to make it easy to use for versatile tea. , And a drying process can be performed at the same time. That is, the intermediate raw material M is supplied to the screw extruder 1
(Screw extruder).

After forming the intermediate raw material M, it is passed through a screw extruder 1. More specifically, the intermediate raw material M is supplied to the screw extruder 1 and the screw extruder 1
During the heating, the temperature of the heating cylinder 2 of the extruder (the temperature of the inner wall portion 21 of the heating cylinder 2) is set to 100 to 200 ° C. so that the intermediate raw material M is subjected to the heat treatment. The temperature of the cylinder inner wall portion 21 is 100 to 200
The reason why the temperature is in the range of ° C. is that if the temperature is lower than 100 ° C., the sterilizing effect is sharply reduced, while if the temperature exceeds 200 ° C., a problem such as discoloration of the finished product P occurs. The heat treatment during the passage through the screw extruder 1 reduces the viable cell count to a number less than the required level of 300 / g. Further, the pulverization process proceeds simultaneously.

The aforementioned screw extruder 1 used in the present embodiment is shown in FIGS. The screw extruder 1 is a device that is often used when melting, kneading, and extruding a material such as plastic. Screw extruder 1
Usually comprises a cylinder 2 composed of a fixed cylinder, an axial screw 3 rotating in the cylinder, a hopper 5 capable of supplying a raw material to the cylinder 22, and an extrusion die. In the present invention, the screw extruder 1 It has been removed (Fig. 1). The intermediate raw material M is supplied to the inside of the cylinder 22 and flows to the right by being dispensed to the hopper 5 as indicated by the white arrow in FIG. 1, but the wall temperature of the cylinder 2 is adjusted independently of the cylinder 2 in the flow direction. A possible heating means 6 is provided. The intermediate raw material M supplied from the hopper 5 into the cylinder 22 is heat-sterilized while being transported under pressure by the screw 3, subjected to kneading and pulverization, and subjected to a discharge port 29.
From the product P. As shown in FIGS. 2 and 3, in the present embodiment, a twin-screw extruder 1 is used. A single axis type may be used, but if it is a biaxial type,
The threaded portion 31a of one screw 3 and the groove 31b of the other screw 3 mesh with each other, so that not only the crushing force is improved but also the productivity is improved by the forced extrusion force. The screw 3 used here has a shape as shown in FIG.
And a stirring pattern section 32 formed by meshing the screw 3 with a flange, and a pulverizing pattern section 33 for pulverizing and atomizing the intermediate raw material M by making the pitch of the screw of the feed pattern section 31 denser. Become. Reference numeral 4 denotes a motor with a speed reducer for rotating the screw 3, and reference numeral 8 denotes a conveyor for receiving and transferring the product P from the discharge port 29.

When the motor 4 is rotated, the tea leaves as the intermediate material M supplied into the cylinder 22 are bitten by the two spiral screws 3 meshing with each other. Heating means 6 such as a heater (or pressurized steam) is guided into the cylinder 2 to heat and control the inner wall portion 21 and the vicinity of the screw 3 to a predetermined temperature. The tea leaves of the intermediate raw material M are transported in the feed pattern section 31 of the screw 3 in the direction of the discharge port, and in the stirring pattern section 32, a certain amount of stagnation and stirring are performed to promote uniform sterilization. In addition, a compression action is generated by the stay. In the crushing pattern section 33, the tea leaves are finely crushed because the spiral interval of the screw 3 is narrow. Thus, the intermediate raw material M supplied to the screw extruder 1 is heated, compressed, agitated, sterilized and dried by evaporation of water at the discharge port 29 while being passed through the cylinder 2, and is taken out to be a product P. At the discharge port 29, the state changes from a high-temperature compression state in the cylinder 22 to a sharply open state to the atmosphere at the discharge port 29, so that moisture evaporates from the tea leaf surface and drying proceeds. The time from when the intermediate material M enters the cylinder 22 to the time when the screw 3 enters the cylinder 3 and is discharged can be arbitrarily changed by changing the rotation speed of the screw.
Within a minute, a desired product P sterilized, crushed and dried with water is obtained in this time.

With respect to the sterilization, in addition to the action of contact heating from the screw 3 and the cylinder 2, there is a method in which moisture contained in tea leaves evaporates and acts as pressurized steam in the cylinder 22. The heating temperature, which is an important factor for improving the sterilizing effect, can be arbitrarily set depending on the intermediate material M, but as described above, the temperature of the inner wall portion 21 of the heating cylinder 2 should be set in the range of 100 to 200 ° C. preferable. When set in the range of 140 to 180 ° C, the product P
In addition, the disinfecting effect required for the quality (the number of viable bacteria is less than 300 / g) can be obtained in a short time while avoiding problems such as discoloration. In addition, the moisture content is 10 to 30%.
Of the intermediate raw material M in the range of (2), when the product P (the product at the outlet 29) is reduced to a moisture content of about 4 to 15%.
In consideration of the storability of the finished product, it is necessary to reduce the moisture content to 5% or less. Therefore, for a product P exceeding 5% moisture content, the moisture content is appropriately adjusted using a dryer or the like used in the green tea manufacturing method. . According to the experimental results, when the moisture content of the intermediate raw material M supplied to the screw extruder 1 exceeds 20%, the moisture content of the product P exceeds 5%, and drying is required. When the moisture content of the intermediate raw material M is 20% or less, the moisture content of the product P at the outlet 29 can be reduced to about 5%, and the discharged product P can be used as a finished product. I am sure that If the moisture content of the intermediate raw material M is less than 10%, the germicidal activity on tea leaves is reduced even if the heating means 6 is set at a predetermined temperature. The tea leaves are not only heat-sterilized by the contact heating from the screw 3 and the cylinder 2, but also the steam generated from the heated tea leaves has a sterilizing effect on the tea leaves in the vicinity thereof. Is reduced (less than 10%), the sterilization ability by this steam starts to decrease. In addition, there is a problem that the disinfection distribution is locally formed, and if the moisture content is too low, the tea leaves are burnt. On the other hand, in the case of raw tea leaves or tea leaves having an excessively high moisture content, the amount of water that can be removed by the screw extruder is almost fixed, so that a burden is imposed on the subsequent drying treatment. Then, a problem that the number of viable bacteria increases during the process is caused.

The product P taken out from the discharge port 29 is often in the form of a powder or an aggregate that can be easily opened with a finger. The higher the moisture content of the intermediate raw material M, the stronger the tendency to aggregate. Immediately after the product P has exited from the outlet 29, the product temperature is high and the product is in the process of evaporating water. Therefore, it is effective to spread the product P to prevent quality deterioration and further reduce the moisture content.

Next, a performance comparison test according to the method for producing multi-purpose tea of the present invention was conducted, and the results are shown in Table 1.

[0018]

[Table 1]

Table 1 shows an example of processing using tea leaves after the middle rubbing step as an intermediate raw material M (a method for producing multipurpose tea). In Table 1, the present apparatus under the processing conditions is the screw extruder 1 described above, and the numerical values in the horizontal row are those when the screw extruder 1 is used. The green tea dryer is a general green tea dryer used in place of the screw extruder 1,
The numerical values in the row indicate the case where the dryer was used. The temperature 170 ° C. below the apparatus is the temperature of the inner wall portion 21 of the heating cylinder 2, and the temperature 80 ° C. below the green tea dryer indicates the temperature inside the dryer. The 18 seconds below the apparatus are the time required to pass through the screw extruder 1, and the 50 minutes below the green tea dryer are the time for the drying process. Since the moisture content of the intermediate raw material M used in the test is preferably lower in the moisture content of the product P after the processing, a material obtained by extending the drying process by making the middle rubbing process longer than usual was prepared. The viable cell count of this intermediate raw material M was 3.3 × 10 ⁴ cells / g. Furthermore, in order to more clearly investigate the bactericidal activity of the present invention, the tea leaves after the coarse kneading step were left at room temperature of about 30 ° C. for 24 hours, and the tea leaves after the middle kneading step were adjusted to increase the number of viable bacteria. The treated tea leaves after the middle rubbing step were also used as the intermediate raw material M. The viable cell count of the intermediate raw material M was 7.9 × 10 ⁶ / g. Processing conditions are
The temperature was set to 170 ° C. and 18 seconds when this apparatus was used, and to 80 ° C. and 50 minutes for a sencha dryer for comparison and comparison. Under such conditions, the intermediate material M was processed.

The moisture content of the product P after the processing is 9.4 in the case of the present apparatus, compared to the case of using a sencha dryer.
%, 6.7%. However, even when the original viable cell count of the intermediate raw material M is 7.9 × 10 ⁶ cells / g, the viable cell count is less than the lower limit of quantification of 300 cells / g (<300 cells) after the treatment with this apparatus. / G), which proves that the production method has a strong sterilizing power. The surface color measured by making the product P processed by this apparatus into powder and almost the same particle size is as follows:
Compared with the one using a sencha dryer, the color tone was slightly darker as indicated by the L value and slightly increased reddish as indicated by the a value, but was acceptable without any problem as the product P.

According to the method for producing a versatile tea having such a constitution, it has an excellent bactericidal action as apparent from the performance comparison test, and is extremely useful for versatile tea which is used at room temperature. In addition, since a certain degree of drying treatment can be performed, the process can be simplified unlike the conventional manufacturing method using steam, microwaves, or the like by replacing and incorporating it into the fine rubbing process of the green tea manufacturing method. Unlike the production method using steam or microwaves after the product is completed, it does not cause any trouble such as discoloration or fragrance deterioration of the product P. Furthermore, since the screw extruder 1 that exerts power in kneading and kneading is used, the product P coming out of the outlet 29 is powdered, so that the product P can be processed without using a separate crushing device. A powdered product P suitable for tea for use has been completed. In addition, the area occupied by the screw extruder 1 used in the method for producing versatile tea of the present invention is almost the same as the area occupied by the processing power of the fine mulling machine in the method for producing green tea. Can be easily introduced. Also, as can be seen from the performance comparison test, the method for producing multi-purpose tea of the present invention has excellent productivity.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention depending on the purpose, application, and the like. Cylinder 2 of screw extruder 1
The shape, size, number, material, etc. of the screw 3, hopper 5, heating means 6, etc. can be appropriately selected according to the application. As the intermediate raw material of the present invention, the final rubbing process in the green tea manufacturing process,
It is also possible to use a finished product after a drying step or the like, which is also within the scope of the present invention. In the case where the number of viable bacteria is large even for a finished product for some reason, sterilization can be performed by implementing the present invention.

[0023]

As described above, the method for producing versatile tea according to the present invention makes it possible to obtain a product capable of controlling the number of viable bacteria while simplifying the process using the drying ability of the sencha production process. In addition, a great effect is obtained, such as simultaneous drying and powdering effective for multipurpose tea.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a screw extruder used in the method for producing multipurpose tea according to the present invention.

FIG. 2 is a front view of the screw of FIG. 1;

FIG. 3 is a partial perspective view of a screw in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Screw extruder 2 Heating cylinder 21 Cylinder inner wall part 3 Screw 31 Feeding pattern part 32 Stirring pattern part 33 Crushing pattern part M Intermediate raw material P Product

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A23F 3/12

Claims (1)

(57) [Claims] 1. An intermediate raw material in which the plucked tea leaves are steamed, and then the steamed and heat-treated tea leaves are subjected to at least a coarse kneading step, a kneading step, and a middle kneading step, so that the water content of the tea leaves falls within a range of 10 to 30%. Thereafter, the intermediate raw material is supplied to a twin- screw extruder, and the screw extruder
Clew is a screw feed part that plays a large role in feeding.
Forming a flange on the screw with the pattern part and meshing
Stir pattern part, and the screw of the feed pattern part
A powder that is denser than the pitch to pulverize and atomize intermediate raw materials
Crushed pattern part, and the tea leaves as the intermediate material
Transported in the direction of the outlet at the Liu's feed pattern and agitated
A certain amount of stagnation and stirring are performed in the pattern section,
The tea leaves are finely crushed in the screw extruder , and while passing through the screw extruder, the temperature of the inner wall portion of the heating cylinder of the screw extruder is set to 100 to 200.
Versatile for manufacturing process of tea characterized in that the heat treatment to the intermediate material is applied as ° C..