Control method and controller based on tea leaf flavor in production of black tea and oolong tea

Abstract

To produce fermented tea in stable quality while grasping a state of processed tea leaves regardless of processing time in production of fermented tea such as black tea and oolong tea.SOLUTION: A numerical value measured by a device capable of measuring flavor of tea leaves is taken into a flavor measurement controller constituted of a display device connected to a CPU, an operation end and control output, and is comparison-operated with a previously set numerical value. Thus, the values are used for control of processes and appropriate period termination determination of the processes in withering, rolling, fermentation and drying processes in production of fermented tea.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a control method and a control device for the production of fermented tea such as black tea and oolong tea. [Background technology]

[0002] Approximately 75% of the world's tea production is black tea, and the remaining 25% is semi-fermented tea and green tea. Green tea, which is well known in Japan, is produced by steaming fresh tea leaves as soon as possible after picking, and then going through several rolling and drying processes. The steaming process also plays a role in deactivating the oxidizing enzymes contained in the tea leaves. Compared to fermented or semi-fermented teas such as black tea and oolong tea, green tea has less aroma.

[0003] Black tea is produced through a withering process, in which freshly picked tea leaves wither, followed by rolling, fermentation, and drying. Black tea is produced by utilizing the activity of oxidizing enzymes in the tea leaves, and therefore does not require the steaming process of green tea. Oolong tea is produced by withering freshly picked tea leaves, roasting them to inactivate the oxidizing enzymes in the tea leaves, and then undergoing multiple rolling and drying processes. Black tea and oolong tea are produced through a process that utilizes the activity of oxidizing enzymes in the tea leaves, which gives them their characteristic floral or fruity aroma. Therefore, particular attention is paid to the aroma of the tea leaves when producing black tea and oolong tea. The release of aroma by the oxidizing enzymes contained in the tea leaves is affected by ambient temperature and humidity, the moisture content of the tea leaves, and other factors, and production conditions must be adjusted accordingly. Each process has been controlled primarily by the worker's visual, olfactory, and tactile judgments, and is controlled primarily by time, rolling pressure, and temperature.

[0004] There are time-independent methods, such as a method for determining the optimum time by focusing on the temperature of the tea leaves during fermentation, but these are limited to the fermentation process and cannot be used for processes other than fermentation, such as withering and rolling. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-153503 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem we were trying to solve was that it was difficult to judge whether the aroma was being developed based on time alone; sometimes the aroma was not fully developed, or conversely, the reaction of the oxidizing enzymes was too long, causing the aroma to weaken or change to an undesirable aroma, so an experienced worker had to carefully assess the state of the aroma. Furthermore, the withering and fermentation processes took a long time, from several hours to over a dozen hours, which placed a great burden on the workers, and because the aroma was a sensory evaluation, it required experience, so it was not something that anyone could easily judge whether the state was good or bad. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a control method based on the aroma of tea leaves, which is characterized by using a device capable of measuring the aroma of tea leaves in the production of fermented tea such as black tea and oolong tea, measuring the aroma of tea leaves at a predetermined location and at a predetermined timing in the tea production process, controlling the tea production machine in that process based on the measured value, measuring the aroma of tea leaves at the specified timing again, and when the measured value reaches a predetermined value, determining that the process is appropriate, terminating that process and moving on to the next process, and

[0008] We provide a control device for a tea-making machine for fermented teas such as black tea and oolong tea, which is equipped with an aroma measuring device that can quantify the aroma of tea leaves, a CPU that can obtain measurements from the aroma measuring device and calculate these values, an operating terminal for inputting necessary items and values ​​such as setting values, a display that shows the calculation results and the status of the process, and a signal line for controlling the aroma measuring device and the tea-making machine, and which measures the aroma of the tea leaves at pre-specified times and adjusts the control amount of items related to the aroma development of the tea-making machine based on the measured value, and also measures the aroma of the tea leaves at pre-specified times and, when the measured value reaches a pre-set value, ends the process and transports the tea leaves to the next process.This control device for a tea-making machine based on tea aroma is characterized by the following: an aroma measuring device that can quantify the aroma of tea leaves, a CPU that can obtain measurements from the aroma measuring device and calculate these values, an operating terminal for inputting necessary items and values ​​such as setting values ​​and [Effects of the Invention]

[0009] Until now, aroma quality has been judged based on time and experience, but now it will be possible to judge whether something is good or bad based on objective numerical values, making it possible to consistently produce tea with a consistent aroma quality.

[0010] Control based on scent measurements allows optimal conditions to be determined regardless of time, automating process control and timely determination, reducing the burden on workers.

[0011] Since the control is based on measured aroma values, it is possible to adjust the control end to suit the condition of the tea leaves, resulting in improved and stable quality. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram of the device configuration. [Figure 2] FIG. 2 shows an example of the device according to the present invention installed in a withering device. [Figure 3-1] Figure 3-1 shows an example of a measurement method using an air collection hood. [Figure 3-2] Figure 3-2 is an example of a sampling measurement method. [Figure 4] Figure 4 is a graph of tea aroma measurements during withering. [Figure 5] Figure 5 is a graph showing the measured values ​​of tea aroma during rolling. [Figure 6] Figure 6 is a graph of tea aroma measurements during fermentation. DETAILED DESCRIPTION OF THE INVENTION

[0013] The main black tea producing regions are India, Kenya, Sri Lanka, and Turkey. While production in Japan is small, it has been increasing in recent years. The aroma-based technology of this invention can also be exported overseas. The globally standardized method of producing black tea consists of four main steps: withering, rolling, fermentation, and drying. The rolling process can sometimes be replaced by CTC.

[0014] An embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of the device of the present invention. An aroma measuring device a is connected to a CPU b, and control signals from the CPU are used to arbitrarily control measurement and stop of the aroma measuring device, and the CPU acquires measured values ​​from the aroma measuring device. The CPU has aroma measurement memory and calculation functions, and is equipped with a display c and an input terminal d that display settings entered by the operator, control variables, etc. The input terminal may be a touch panel display integrated with the display. Furthermore, it is equipped with a signal line e that transmits control variables to the tea manufacturing machine, and a buzzer output (not shown) for indicating the end of the process or for alarms, etc.

[0015] This will be explained using the withering process in black tea production as an example. Figure 2 shows an example of installation in the withering process. The withering container shown in the figure is composed of a single layer laid flat, but some containers are stacked multiple times. In the withering process, it is important to agitate the tea leaves appropriately so that they are exposed to sufficient air to promote the activity of oxidizing enzymes, and withering containers stacked in multiple layers are agitated as the tea leaves fall to the lower layers. Withering containers composed of a single layer are equipped with a conveyor that transfers the removed tea leaves to the container itself or to other empty containers, and are agitated as the tea leaves are transferred and dropped during transport.

[0016] The withering container f is equipped with a ventilation system and a heating system to accelerate withering. To measure the aroma of the tea leaves stored in the withering container f, an aroma measurement hood h is installed on top of the container, to which an aroma measurement device a is connected. The aroma measurement device's intake port is preferably equipped with a control device such as a solenoid valve l to appropriately shut off the aroma from the hood. Furthermore, since the aroma measurement device requires periodic calibration using odorless air, it is preferable to attach a separate bifurcated hose to the intake port for air intake, and control the intake path with a solenoid valve or similar device to appropriately allocate the air collection path for measurement and calibration (not shown). The aroma measurement control device g is connected to the aroma measurement control device g, which consists of a CPU b, a display c, an input terminal d, and a signal line e (see Figure 1). Wiring is provided to acquire measurements from the aroma measurement device and control the withering container. The figure shows a case where there is one withering container, but if there are multiple containers, the configuration shown in Figure 2 can be increased by the number of containers, or one aroma measurement control device can be used for several containers.

[0017] As shown in Figure 3-1, the measurement method involves installing a hood on top of the container to suck in the tea leaf aroma. In the rolling machine m, tea leaves are placed in a horizontally rotating bowl, and rolling pressure is applied from above using rolling plates, rolling the tea leaves as they rotate. The rolling plates move up and down as a process control element, and there are times when the tea leaves are not being rolled, so some ingenuity is required, such as synchronizing the measurement so that the aroma is measured when rolling pressure is being applied. As shown in Figure 3-2, when the tea leaves are being rolled, the tea leaf aroma is collected from an intake pipe installed on rolling plate m'.

[0018] The air collection hood h does not necessarily have to be a hollowed-out hemisphere. For example, a CTC (an acronym for Crush, Tear, and Curl) machine is a cylinder approximately 1 m long and 30 cm in diameter, equipped with fine sawtooth blades on its surface. Two of these cylinders rotate at different speeds adjacent to each other, and the tea leaves are processed by passing between them. When collecting tea leaf aroma using a tea processing machine like a CTC, the aroma is collected from the top of the two adjacent cylinders, so an air collection hood shaped like a hollowed-out rectangular parallelepiped or semi-cylindrical cylinder is appropriate. While we have provided examples of air collection methods for measuring tea leaf aroma, any method is acceptable as long as it reliably measures the tea leaf aroma. [Example]

[0019] Figure 4 is a graph of the aroma measurements of tea leaves during the withering process. Looking at it broadly, the measurements increase once after 4-5 hours, then decrease, reaching a maximum after 22 hours. Generally, the withering process takes between 10 and 20 hours. It can be seen that the optimum time for withering in this case was around 22 hours.

[0020] Figure 5 is a graph of the aroma measurements of tea leaves during rolling. The aroma measurements increased rapidly after 10 minutes, peaked at 20 minutes, and then reached a maximum at 50 minutes. This suggests that the optimum time for the rolling process was around 50 minutes.

[0021] Figure 6 shows a graph of the aroma measurements of tea leaves during fermentation. The aroma measurements remained high from the beginning of the fermentation process, with peaks observed at 30 and 120 minutes.

[0022] Examples of control include controlling the temperature and airflow of the tea processing machine, as well as other factors that affect aroma development in each process, depending on the difference between the aroma measurement value at a set time and the preset aroma target value at that time. More specifically, if the aroma measurement value at a set time is lower than the target value at that time, in the withering process, the temperature is increased by a predetermined amount or the airflow is increased. In the rolling process, the rolling time is extended to promote aroma development. In the fermentation process, the temperature is increased, humidity is increased, etc.

[0023] Conversely, if the value is greater than the target value, the control amount is adjusted to delay the release of the aroma. This is the opposite of the control operations exemplified in the previous paragraphs. In addition to active control, it is also possible to measure at predetermined times or intervals during the process and monitor changes in the values.

[0024] It is also possible to use aroma measurements to determine the appropriate timing for each process. In the case of Figure 4, when the aroma measurement exceeds 140 (after 22 hours), it can be determined that it is the appropriate time to start the withering process, and when a peak is detected after 50 minutes in the rolling process, a buzzer can be sounded to indicate the end of the process or a control signal can be output to send the product to the next process.

[0025] The optimum time does not necessarily have to be the maximum measured value, but can be set as appropriate. The optimum time can be determined not simply by reaching a certain value, but also by comparing the value after a preset time has elapsed, or by determining the peak itself, as long as the aroma measurement value is used. In Figure 6, the peak is detected 30 minutes after the start of the process, but since changes in tea polyphenols due to fermentation are also important in addition to aroma enhancement, the optimum time can also be determined by detecting the peak 60 minutes or later after the start of the process. The present invention can be applied not only to black tea production, but also to the withering process in oolong tea production, where aroma enhancement is an important factor. [Industrial Applicability]

[0026] By directly measuring the aroma of tea leaves, it becomes possible to control and judge the quality of tea leaves in accordance with their condition, enabling the production of tea with a stable aroma quality. In addition, workers can easily know the condition of the tea leaves, reducing their workload. [Explanation of symbols]

[0027] a. Aroma measurement device b CPU c Display d Input terminal e Signal line f Wilting container g. Aroma measurement and control device h Air collection hood i Tea leaf sampling box j Air cylinder k Sampling conveyor Solenoid valve m rolling machine m'Kneading press

Claims

1. This method for controlling a tea-making machine based on the aroma of tea leaves is characterized in that, in the production of fermented tea such as black tea and oolong tea, the aroma of tea leaves is measured at a pre-specified location and a pre-specified timing in the tea-making process using a device capable of measuring the aroma of tea leaves, and the tea-making machine in the process is controlled based on the measured value.

2. This control method is characterized in that in the production of fermented tea such as black tea and oolong tea, an apparatus capable of measuring the aroma of tea leaves is used to measure the aroma of tea leaves at a predetermined location and at a predetermined timing in the tea production process, and when the measured value reaches a predetermined value, it is determined that the process is at an appropriate time, the process is terminated, and the process proceeds to the next process.

3. 3. The control method according to claim 1 or 2, which is used in at least one of the tea processing steps in the production of fermented tea: withering, rolling, fermentation and drying.

4. A control device for a tea-making machine for fermented teas such as black tea and oolong tea, comprising: an aroma measuring device that can quantify the aroma of tea leaves; a CPU that can obtain measurements from the aroma measuring device and calculate these values; an operating terminal for inputting necessary items and values ​​such as setting values; a display that displays the calculation results and the status of the process; and a signal line for controlling the aroma measuring device and the tea-making machine, characterized in that the control device measures the aroma of tea leaves at pre-specified times and adjusts the control amount of items related to the aroma enhancement of the tea-making machine based on the measured values.

5. A control device for a tea-making machine for fermented teas such as black tea and oolong tea, comprising: an aroma measuring device that can quantify the aroma of tea leaves; a CPU that can obtain measurements from the aroma measuring device and calculate those values; an operating terminal for inputting necessary items and values ​​such as setting values; a display that displays the calculation results and the status of the process; and a signal line for controlling the aroma measuring device and a device for transporting the tea leaves to the next process, characterized in that the control device measures the aroma of the tea leaves at pre-specified times, and when the measured value reaches a pre-set value, the process is terminated and the tea leaves are transported to the next process.

6. 6. The control device according to claim 4 or 5, wherein the control device is provided in at least one tea-processing machine for a withering process, a rolling process, a fermentation process, and a drying process among the tea-processing processes in the production of fermented tea.

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