JP4606960B2 - Tea beverage sterilization method - Google Patents

Description

  The present invention relates to a method for sterilizing tea beverages. According to the present invention, since heat-resistant spore bacteria that could not be sterilized conventionally can be easily sterilized, the present invention can be applied to tea beverages (hereinafter sometimes referred to as liquid foods). It is particularly useful for further enhancing safety and storage.

  Conventionally, in the industry, in order to sterilize microorganisms, it is common to sterilize by heating an object to be processed. From the viewpoint of controlling microorganisms, microorganisms are controlled by using antibacterial agents, bacteriostatic agents, etc., or adjusting pH. Moreover, in recent years when the use of food additives is not preferred, interest in physical or electrical sterilization methods has increased, and for example, a method using a high voltage pulse has been proposed (see Non-Patent Document 1). .

Surely, this high voltage pulse method is an excellent method, but since it is necessary to store the sterilization target in the tank once, it is a batch type process and cannot be continuously processed, and the sterilization time is long. Deterioration of flavor and quality is inevitable, and it is hard to say that it is fully satisfactory.
Journal of Japan Society for Food Engineering, Vol. 4, no. 2, p47-51 (June 15, 2003)

  The present invention effectively sterilizes microorganisms (including heat-resistant spore bacteria) that cause problems such as spoilage and deterioration in liquid foods, improves the storage stability of liquid foods, and is used for controlling microorganisms. The purpose is to reduce the amount of additives and prevent or suppress heat deterioration associated with heat sterilization, for example, prevent or suppress decomposition of active ingredients (catechin and the like). Furthermore, it aims at the efficiency improvement of sterilization.

  The present invention has been made to achieve the above object, and as a result of examination from various directions, attention has been paid to an electrical method, not a chemical method, and prevention of changes in active ingredients associated with heating of food. When an electric field is generated by applying a voltage using an AC power source, aiming at prevention and control of changes in fragrance components, control, fragrance components, and reduction of various additives for microbial control, changes in the above effective components and fragrance components For the first time, it has been found that heat-resistant spore bacteria that can effectively sterilize microorganisms more effectively and can be sterilized more effectively in a short time can be sterilized more effectively. And based on this useful new knowledge, the invention regarding an alternating current high electric field sterilization processing system was completed, and the result was previously applied for a patent as Japanese Patent Application No. 2005-61139.

  This AC high electric field sterilization treatment system is a very good system, but the present inventors are not satisfied with this, and intend to improve it further. At that time, the demand has rapidly increased in recent years. In particular, the goal was to develop a system suitable for sterilization of tea beverages.

  Therefore, we examined from various directions and focused on filtration. Therefore, when the tea beverage was sterilized by providing a filtration step (step for removing insoluble solids) before the AC high electric field sterilization treatment, scale adhesion to the pipes and electrodes was prevented and suppressed, and the voltage was constant. As a result, the sterilization is stably performed, and the occurrence of secondary aggregation is suppressed even after long-term storage, and further, not only the discoloration such as browning of tea is prevented and suppressed, but also catechin is useful. It was discovered for the first time that it was effective in preventing or suppressing the alteration and decomposition of ingredients, and particularly useful in tea beverages. Normally, the case of “suppressed” completely is “prevented”, but in this specification, “prevented” may mean incomplete “suppressed”.

  The present invention has been made on the basis of these useful new findings, and is a basic technique of a tea beverage sterilization method characterized in that the filtration step is performed once or more before the AC high electric field sterilization is performed. It is an idea. The AC high electric field sterilization is performed in accordance with the previously filed Japanese Patent Application No. 2005-61139 (filed on Mar. 4, 2005).

  That is, the present invention is a method for sterilizing a tea beverage, which is a liquid food having electrical conductivity, using an energization unit sandwiched between one or more pairs of metal electrodes, and the energization unit is a sealed system, Prior to this AC high electric field sterilization treatment, an AC power source is connected to the electrode of the energization unit, and microorganisms are sterilized by continuously passing an unsterilized tea beverage through the energized unit to which a voltage is applied. The present invention provides a method for sterilizing a tea beverage characterized by filtering the sterilized tea beverage one or more times.

  More preferably, the filtration step is performed before the AC high electric field sterilization and before passing through the pump, and the type of filtration is filter cloth, metal filter exceeding 200 mesh, centrifugal separation, precision It is at least one of filtration, and removal of particles having a filtration size of 75 μm or more is included as one embodiment.

  In addition, when a high electric field treatment of 60 L per hour is applied, a voltage of 2.5 kV / cm or more is applied to the electrode, and the product temperature is 120 ° C. or more. Within one second is also included as one embodiment.

  The present invention also provides a sterilization method characterized by preventing or suppressing browning of tea and preventing or suppressing decomposition of an active ingredient (for example, catechin), and a sterilization method under deoxygenated conditions.

  Furthermore, this invention provides the method of disinfecting tea beverages including black tea, barley tea, oolong tea, and various blended teas in addition to green tea.

  According to the present invention, the liquid food can be sterilized continuously by passing the liquid food through the electric field in the energization unit. In addition, at least the inside of the current-carrying unit can be pressurized to sterilize not only ordinary microorganisms but also heat-resistant microorganisms, especially heat-resistant spore bacteria within 1 second, so that the flavor and quality of liquid foods can be reduced. It is possible to prevent the deterioration of the active ingredient, the decrease in the active ingredient, and the alteration, and it is particularly suitable as a liquid food sterilization system.

  In addition, from the standpoint of the device, each device and means in addition to the current-carrying unit are connected by pipes and become a sealed system, so that their interior is pressurized by the pressure of the liquid food itself fed by the pump. It is not necessary to house the entire apparatus in a pressure vessel, the apparatus is compact, the operation is greatly simplified, and sterilization can be achieved very efficiently.

  Liquid foods, especially liquid foods in containers such as tea filled in PET bottles, are often sold in vending machines and are consumed after a certain period of time. If heat-resistant spore bacteria remain, they propagate during this period, resulting in spoilage and quality degradation. However, in order to completely sterilize such microorganisms, they must be treated at a high temperature and a high pressure for a long time, and an increase in cost, flavor of liquid food, and deterioration of quality are inevitable.

  The present invention has been successful for the first time to solve these problems all at once, and is a sterilization method particularly suited to the technical field of food and drink. In addition, since it is not necessary to use a large and complicated pressurizing device, it is excellent in terms of cost, operation and work safety, and it is liquid in that a very high sterilizing effect can be obtained with a small device. It is particularly outstanding as a food and beverage sterilization system.

  And in the present invention, since the filtration treatment is organically combined with the alternating current high electric field sterilization treatment, in addition to the above-mentioned remarkable effect by the alternating current high electric field sterilization treatment, A remarkable effect is produced.

  That is, since scale can be prevented or adhered to pipes, electrodes, device walls, etc., the voltage is constant and sterilization is performed stably. In addition, since the scale is prevented or suppressed from adhering to the electrode, the electrode replacement frequency or cleaning frequency is reduced, and the efficiency can be improved within a range where the flavor is not impaired.

  Moreover, when it preserve | saves for a long term, although secondary aggregation generate | occur | produces, according to this invention, generation | occurrence | production of this secondary aggregation is suppressed. Furthermore, according to the sterilization method according to the present invention, browning and / or component change (quality deterioration) of tea is prevented or suppressed, and a color closer to untreated than UHT sterilization can be maintained, such as catechin. The remarkable effect that change (deterioration) of useful components can be prevented or suppressed is also exhibited.

  In the present invention, an electric field is generated between electrodes by passing liquid food after filtration through an energization unit to which a voltage is applied, and microorganisms are continuously sterilized. By applying further pressure inside the energizing unit as desired, heat-resistant spore bacteria that were difficult to sterilize in liquid can be sterilized in a very short time, and the original flavor and quality of tea beverages are impaired. Without a significant increase in efficiency.

  In order to carry out the present invention, the liquid food after filtration (unsterilized tea beverage) may be processed by the AC high electric field sterilization system according to the prior application. The filtration treatment may be performed separately, or as shown in FIG. 1, it is possible to provide a filtration step before the pump and continuously sterilize.

  In the filtration process, at least one of filtration cloth, metal filter with mesh exceeding 200 mesh, Tyler standard sieve with mesh exceeding 200 mesh and narrow opening, centrifugal separation, and microfiltration is used. Is done. Moreover, as a filtration size, it is less than 75 micrometers, Preferably it is 50 micrometers or less, Comprising: A suitable range is 0.1-45 micrometers, and a more suitable range is 1-30 micrometers.

  The filtration treatment may be performed once, or may be performed twice or more, or three or more times, or four or more times if necessary. In that case, the same kind of filtration and the filtration size may be used, or different kinds of filtration may be combined.

What is necessary is just to process the unsterilized liquid (unsterilized tea drink) which complete | finished the filtration process in the alternating current high electric field sterilization system which concerns on a prior application.
That is, the unsterilized liquid after the filtration treatment can be continuously sterilized using an apparatus as exemplified below.

  The liquid supply port and the liquid discharge port are connected to an energization unit, and a pair of metal electrodes are arranged on the energization unit, and an AC power source is connected to these electrodes to generate an electric field between the electrodes. A continuous sterilization apparatus for liquid food, characterized in that the inside of the energizing unit can be pressurized.

  The inside of the energizing unit may be an open system, but the inside of the energizing unit can be pressurized by using a sealed system. The energization unit can be pressurized without accommodating the energization unit in a pressurized container by making itself a sealed system. For example, since the energization unit is hermetically sealed, a pressurized gas may be supplied into the energization unit, or the pressurized state can be achieved only by the pressure of the liquid that is passed through the energization unit by a pump.

  Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings.

  FIG. 1 illustrates an embodiment of a liquid food sterilization apparatus according to the present invention. The upper part is a first example, the middle part is a second example, and the lower part is a third example. In FIG. 1, the apparatus excluding the filtration step is a liquid food continuous sterilization apparatus according to the prior application, that is, an AC high electric field sterilization apparatus. Note that the present invention can be implemented in whole or in part in a deoxygenated state (in an inert gas atmosphere, inert gas replacement, etc.).

  As shown in FIG. 1, the liquid food continuous sterilization apparatus according to the present invention includes a liquid feeding means, a (preheating device), an energizing unit, a cooling device, and a pressure holding valve in addition to the filtering means. One or more pairs of metal electrodes are arranged, and an AC power supply is connected to these electrodes, and at least a preheating device, a power supply unit, a cooling device, and a pressure holding valve are connected to form an internal closed system. is there. When heating is necessary in advance for sterilization, a preheating device may be used.

  Specifically, the filtering means is as described above. More specifically, for example, a pump is used as the liquid feeding means, and from a commonly used plunger pump, cylinder pump, rotary pump, etc. In addition to using a heat exchange plate (for heating) as a preheating device (second embodiment: middle stage), as in the third embodiment (lower stage), an energization unit is provided and used as a preheating device. Joule heat may be used. The upper stage is the first embodiment, in which no preheating is performed.

  The energization unit (indicated as a high electric field electrode in the drawing) is formed with a channel through which the liquid supplied from the liquid supply port flows, and this channel is at least connected to an AC power source (high frequency AC power source). It has a configuration with a pair of electrodes facing it. Specifically, an AC power source is connected to the electrodes of the energization unit, and the electrodes to be connected can be sterilized by adopting a configuration in which at least one pair of metal electrodes covered with an insulator is faced. Further, the insulator covering the electrode is in a sealed state so that it can be pressurized.

  As the type of electrode, there is no problem as long as it is a metal having electrical conductivity, but in order to prevent deterioration such as corrosion of the electrode, titanium, platinum or stainless steel is desirable. In addition, a plurality of electrodes can be stacked by stacking a plurality of insulators on the electrodes of the energization unit.

  Since the liquid food is heated by the Joule heat by performing the energization process in the energization unit, flavor and quality deterioration occur. Therefore, if it is not desired, a cooling means may be provided, for example, a heat exchange plate (cooling plate) Can be used.

  The liquid food sterilized in this way is taken out of the system through a pressure holding valve (pressure regulating valve). The pressure adjustment is adjusted by the liquid feeding means and the pressure holding valve to maintain an appropriate state in the energizing unit.

  The continuous sterilization apparatus according to the present invention is thus connected by piping (pipe: indicated by a black arrow in the figure) from the filtration step and the pump to the pressure holding valve, and constitutes a sealed system itself. . Therefore, the preheating means to the pressure holding valve, at least the energizing unit, can be pressurized by itself without being arranged in the pressurized container, so this apparatus is installed in an open space. However, it is very characteristic and efficient in that the high pressure electric field sterilization treatment under pressure can be performed. That is, this is fundamentally different from the case where the energization unit is housed in the pressurization container and the energization unit is pressurized from the outside.

  Unlike the case where this device is newly housed in a pressurized container by adopting such a configuration, each device and means are connected by a pipe, so that pressure control is easy. Fine adjustment is also possible. As the pressurizing means, pressurized gas may be used, and the water pressure (hydraulic pressure) of the liquid food itself can be used. Therefore, by controlling the pump (and holding valve if necessary), it is exceptional. Without providing a separate pressurizing means, the pressurized state can be obtained by utilizing the water pressure of the liquid food, and this apparatus can be said to be a self-contained apparatus. The pressurizing means is preferably water pressure (hydraulic pressure), and when a pressurized gas is used, the pressure during the treatment can be kept constant.

  In order to sterilize liquid food, first, liquid food (unsterilized product) is filtered in a filtration step, then passed through a pump, preheated, cooled in a current-carrying unit, and then cooled. Although it may be taken out of the system as a sterilized product through a pressure holding valve, the present invention will be described in detail below with an example in which the inside is pressurized.

  Liquid food (after preheating if necessary) is energized under pressure in the energizing unit, but the pressure in the energizing unit is 40 ° C when the voltage is applied to the liquid food. It is desirable that the pressure be equal to or higher than the saturated water vapor pressure when added. The reason for this is to prevent the deterioration of the electrode by suppressing sparks (a phenomenon in which discharge is temporarily generated) on the electrode side, efficiently achieving microbial sterilization, and preventing minute sparks. The pressure is 0.6 MPa or more, preferably 0.8 MPa or more, and more preferably 0.9 MPa or more at 120 ° C., and the addition value may be determined according to this.

  The voltage application time of the electrodes in the energization unit is very short and is preferably within 1 second. This is because if the voltage application time is too long, a sufficient applied voltage cannot be secured. Thus, the application time is within 1 second, preferably within 0.5 seconds, and in the examples, it is exemplified within 0.05 seconds, such as 0.006 to 0.044 seconds. Thus, in the present invention, the voltage application time is within 1 second, for example, within 0.1 second, which is very characteristic in that it is extremely short.

  Regarding the relationship between the distance between electrodes, applied voltage, and voltage application time, the applied voltage (V / cm) to the electrode per 1 cm distance between the electrodes and the voltage application time to the liquid food (the passage time of the liquid food) It is desirable that the integration coefficient of (seconds) is 50 or more. This relationship is because when the coefficient is 50 or more, sterilization of microorganisms can be achieved more than normal heat sterilization (such as UHT sterilization and retort sterilization). This coefficient may be 50 or more, and there is no particular limit, but usually 60 to 200 is exemplified. These relationships are represented by mathematical formulas as follows.

Applied voltage per electrode distance (V / cm) × application time (seconds) ≧ 50
(In the formula, V represents voltage, and cm represents the distance between the electrodes.)

  Further, in the present invention, there is no problem even if the energization unit is passed through the energization unit twice or more, or a preheated plate using a heat exchange plate or the like is passed through the energization unit. In FIG. 1, the apparatus of the present invention is shown as a horizontal type, but a saddle type can also be used.

  The frequency of the power source is 50 kHz or less, preferably 20 kHz or less, preferably 10 to 20 kHz from the viewpoint of energy efficiency and corrosion resistance with respect to the electrode, and 5 kHz or less can also be used.

  The microorganisms that can be sterilized by the present invention are microorganisms that require heat sterilization, and are particularly suitable for microorganisms that cause deterioration or decay. Furthermore, sterilization by the method of the present invention is effective for heat-resistant microorganisms that require sufficient sterilization even by heat sterilization and microorganisms that form spores. For example, Bacillus genus, Geobacillus genus, Alicyclobacillus genus, Morella genus, Clostridium genus, Thermoanaerobacter genus and the like centering on Gram-positive bacteria are exemplified.

  Furthermore, since the liquid food is heated by generating resistance heating (Joule heat) when energized, the liquid food is immediately passed through the energizing unit so that excessive heat is not applied. It is desirable that the structure be cooled.

In the present invention, tea drinks are widely treated, and the following tea drinks are exemplified.
Tea leaves: Green tea, black tea, barley tea, oolong tea and various blended teas can be used.
Extraction method: No problem if it is a general extraction condition.
Kneader extraction, immersion extraction, and the like can be selected as appropriate.
Extraction condition: No problem if it is a general extraction condition.
60-95 degreeC is suitable temperature for extraction, but it does not need to be limited to this.
Auxiliary raw materials: Additives such as milk raw materials such as milk, sugars, acidulants, fragrances and emulsifiers, and pH adjusters can be used.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
Preparation of microorganisms Spore formation was performed in a normal bouillon medium manufactured by Eiken Equipment Co., Ltd. using thermostable microorganism spores Bacillus subtilis JCM2477, and the formed spores were stored in 0.85% physiological saline containing 10% glycerol, and kept at −85 ° C. The frozen product was used as a microorganism.

Effect of pressure Using the device shown in Fig. 1 (excluding the filtration step), pressurize the inside of the current-carrying unit to 0.4, 0.6, 0.8, 0.95 MPa using the above microorganisms to give electrical conductivity. For this purpose, a suspension of microorganisms in 0.01% saline was passed through. The electrodes used were 6 mm (width) x 32 mm (height) x 1 mm gap between electrodes and 6 mm (width) x 16 mm (height) x 1 mm gap between electrodes, and using a pump, the flow rate was 1 L / min. Liquid. The AC electric field application time of each electrode was 0.011 seconds and 0.006 seconds, and the applied electric field was 8000 V / cm and 8500 V / cm (frequency 20 kHz). The product temperature at that time was 115 ° C. It cools to normal temperature within 1 second after a process, and it shows by the number of surviving bacteria (logarithm)-initial spore bacteria number (logarithm) (FIG. 2). The positive value of this value indicates the number of dead sterilizations.

  The number of remaining microbial spores was measured by counting the number of colonies on a standard agar medium made by Eiken Equipment. From the above results, it is possible to increase the pressure by adding 40 ° C. to 115 ° C. (vapor pressure 0.7 MPa) to 0.45 MPa or higher. It has been found that subtilis spores can be efficiently sterilized.

(Example 2)
Effect of applied electric field time and applied voltage The inside of the energizing unit was pressurized to 0.9 MPa using the microorganism used in Example 1, and the electrodes used were 6 mm (width) × 32 mm (height) × interelectrode spacing 1 mm, 2 mm, and The liquid was passed at a frequency of 20 kHz and a flow rate of 1 L / min using 4 mm and 6 mm (width) × 24 mm (height) × interelectrode spacing of 2 mm and 4 mm. The AC electric field application time for each electrode is shown in Table 1 below.

* Applied voltage () indicates the applied voltage (V / mm) per mm
Figures in parentheses are applied voltages (V) during actual testing.

  Moreover, in order to change the applied electric field strength, the treatment was performed while changing the saline concentration when passing through the solution to 0.01 to 0.2%. The product temperature at that time was 115 ° C. It cools to normal temperature within 1 second after a process, and shows by the numerical value which deducted the number of initial spore bacteria from the number of survival bacteria (FIG. 3). In Table 1 and FIG. 3, the circled numbers correspond to each other.

  The number of remaining microbial spores was measured by counting the number of colonies on a standard agar medium made by Eiken Equipment. In addition, the B. Since D115 ° C. = 0.029 in a subtilis bath (ie, Death Value (D value) at 115 ° C. is 0.029 minutes), the number of bacteria that can be sterilized in 1 second (logarithm) is 0.57. Therefore, by setting the coefficient to 50 or more, It has been found that subtilis spores can be effectively sterilized.

(Example 3)
Green tea was produced according to the tea production flow shown in FIG. 4, and the obtained filtered green tea was compared for bactericidal effect, color change, and catechin content for different methods.

(1) Comparison of bactericidal effect The bactericidal effect was compared by the method of high electric field sterilization (Example) and UHT sterilization (comparative example). The sterilization techniques and results are shown in Table 2 and Table 3, respectively. As the indicator bacterium, Bacillus subtilis JCM2744 was used. As the UHT model, a Model 25HV Hybrid UHT / LTST sterilizer manufactured by Micro Thermics was used.

  As is clear from the above results, the high electric field sterilization effect is in the order of round numbers 1> 2> 3> 4, and the UHT sterilization effect is in the order of round numbers 5> 6> 7> 8.

  As a result of comparison between high electric field sterilization and UHT sterilization, high electric field 1 and UHT 5 have the same degree of sterilization efficiency, high electric field 3 and UHT 6 have similar sterilization efficiency, and high electric field 4 and UHT 7 are Both were found to be close sterilization efficiencies (note that each number represents a round number).

(2) Comparison of color change The results shown in Table 4 were obtained by comparing the color change caused by the difference in sterilization conditions and sterilization methods at the same level of sterilization effect. As a color difference analyzer, NIPPON DENSHOKU Color Meter ZE-2000 was used.

<Comparison with Lab>
L is brightness, a is red-green, and b is yellow. From the above results, especially as the value of b increases, yellow becomes stronger, that is, UHT sterilization is stronger in yellow than high electric field sterilization, and the tea color is slightly bluish (untreated color) It is clear that the high electric field sterilization is more suitable for close to.

<Comparison with YI>
The color shift in the yellow direction from white (O) is shown as a positive value. Yellow increases as the value increases, and high electric field sterilization is more yellow than the original tea color (untreated color) than UHT sterilization. It became clear that it was not strong, that is, discoloration (brown change) by heat was suppressed by high electric field sterilization.

(3) Comparison of catechins In the same level of bactericidal effect, changes in the catechin content caused by differences in bactericidal conditions and bactericidal techniques were compared. The analysis of catechin was measured by the HPLC method.

That is, the reagent (A liquid, B liquid) was prepared as follows.
Liquid A Water: acetonitrile: 85% phosphoric acid = 95.45: 4.50: 0.05 (v / v / v) = 2.8635 L: 0.135 L: 0.0015 L
Liquid B Water: acetonitrile: 85% phosphoric acid = 49.95: 50.0: 0.05 (v / v / v) = 1.485L: 1.5L: 0.0015L

The analysis conditions were as follows.
Column: Develosil ODS-HG (4.6 mm × 150 mm)
-Column temperature: 40 ° C
・ Flow rate: 1.0ml / min
・ Detection wavelength: UV 231nm
Details are shown in Table 5.

The results obtained are shown in Table 6. The abbreviations in the table represent the following substances, respectively.
Epigallocatechin gallate (EGCg), epicatechin gallate (ECg), epigallocatechin (EGC), epicatechin (EC). The unit of catechin content is expressed in ppm.

  EGCg and ECg, which are easily decomposed by heat, are clear from the above-mentioned catechin content comparison results, when compared with high electric field and UHT sterilization, overall, high electric field sterilization remains without being decomposed. It became clear that. (High electric field sterilization is closer to the untreated value)

Example 4
According to the tea production flow (Example) shown in FIG. 5 and the tea production flow (Comparative Example) shown in FIG. 6, green tea was produced, and the obtained filtered green tea was different depending on the filtration process. The high electric field sterilization effect was compared.

  The sterilization methods and results are shown in Tables 7 and 8. In addition, Bacillus subtilis JCM2744 was used as the indicator bacteria.

  As is clear from the above results, as a result of examination from the aspect of sterilization efficiency, in the comparative example, the voltage is likely to be low, the sterilization efficiency is lowered, and the scale is easily accumulated on the electrode. ) Is necessary to increase.

It is an apparatus block diagram which shows the continuous sterilization apparatus which concerns on this invention. The relationship between processing pressure and the number of germicidal bacteria is shown. The relationship between the electrode used and the number of germicidal bacteria is shown. The tea production flow is shown. The tea production flow (Example) is shown. The tea production flow (comparative example) is shown.

Claims (9)

  A method of sterilizing a tea beverage, which is a liquid food having electrical conductivity, using an energization unit sandwiched between one or more pairs of metal electrodes, wherein the energization unit is a sealed system and is used as an electrode of the energization unit. Sterilizes microorganisms by connecting an AC power supply and continuously passing the unsterilized tea beverage through an energized unit to which a voltage is applied, and prior to this AC high electric field sterilization treatment, Or a tea beverage sterilization method, characterized by performing filtration treatment more times.   The method according to claim 1, wherein the inside of the energizing unit is pressurized by the tea beverage itself that passes through the energizing unit.   The method according to claim 1, wherein particles having a size of 75 μm or more are removed in the filtration treatment.   The method according to claim 3, wherein the filtration treatment is at least one selected from filtration with a filter cloth, filtration with a metal filter having a pore size exceeding 200 mesh, centrifugation, and microfiltration.   The voltage of 2.5 kV / cm or more is applied to the electrode when the high electric field treatment is performed at 60 L per hour, and the product temperature is 120 ° C. or more. 5. the method of.   6. The method according to any one of claims 1 to 5, wherein the applied electric field time is within 1 second.   The method according to any one of claims 1 to 6, which prevents or suppresses browning of tea and / or prevents or suppresses decomposition of catechin.   The method according to claim 1, wherein the method is performed under deoxygenation conditions.   The method according to any one of claims 1 to 8, wherein the tea beverage is at least one selected from green tea, black tea, barley tea, oolong tea, and blended tea.

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