JPS6348498B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing instant tea, particularly instant tea such as green tea, hojicha, and black tea. The conventional manufacturing method for instant tea, including green tea, hojicha, black tea, etc., uses a large amount of hot water to elute the tea components from the raw tea leaves, and then concentrates this eluate. It is dried to obtain powdered instant tea, and even if it is eluted with hot water, the concentration of tea components in the eluate is extremely low, with a solid content of less than a few percent. Because of the elution, the aromatic components of the tea tend to volatilize and dissipate, and the amount of water removed during concentrated drying reaches approximately 95% or more, which requires a large amount of heat and cost. As the water evaporates, most of the tea flavor components present in the eluate are dissipated, and the resulting dry powdered tea products usually have extremely low flavor and poor color tone. In addition, a method of extracting tea components using a solvent has been used, but at present only a product that is not much different from that obtained by elution with hot water is obtained. The purpose of the instant tea manufacturing method of the present invention is to press and exude tea components from raw tea leaves at low temperatures without eluting them with hot water, thereby making it possible to obtain a concentrated liquid of tea components. Prevents components, especially flavor components, from dissipating due to heat during conventional elution, and significantly reduces the amount of water removed during the concentration or drying process to obtain tea extract or dry powder, resulting in loss of tea flavor components. The purpose of this invention is to obtain instant tea in the form of a concentrated tea extract or dry powder with excellent flavor and color, and which has excellent solubility in both hot and cold water for tea drinking. The purpose is to obtain instant tea that does not require a teapot or the like and has a flavor and color tone equal to or better than that of a tea liquid obtained by dissolving high-quality tea leaves in hot water at an appropriate temperature using a teapot. The method for producing instant tea of the present invention involves compressing a mixture of crushed and humidified dried tea leaves and adding crushed volcanic rock powder to exude mainly water-soluble components of the tea leaves and to transform the volcanic rock powder into Then, the volcanic rock powder is separated from the mixture, and water at a temperature of 40°C or less is added to elute the mainly water-soluble components of the tea leaves absorbed into the volcanic rock powder as a concentrated tea liquid. After the tea liquid is filtered, it is dried to obtain instant tea powder. The instant tea of the present application is a general term for the dry powder or concentrated extract of green tea, hojicha, black tea, and other ordinary teas that can be easily consumed by pouring hot or cold water. In addition, exudation in this application means that tea components and the like exude together with water from raw tea leaves, and absorption includes not only water absorption but also adsorption. The raw material tea leaves to be used may be dried tea leaves selected according to the desired type of instant tea; for example, in the case of instant green tea, dried green tea leaves are used as the raw material tea leaves. In this case, according to the manufacturing method of the present application, if the raw material tea leaves are of high quality, higher quality instant tea can be obtained, but it is also possible to obtain instant tea with excellent flavor even if raw material tea leaves that are not of high quality are used. It is. The raw material tea leaves are pre-pulverized into a powder in order to uniformly humidify the tea leaves and to facilitate exudation of the mainly water-soluble components of the tea leaves during compression.
The degree of pulverization is 60 mesh or less, preferably 80 mesh or less. During this pulverization and all subsequent steps, it is necessary to pay attention to preventing the aroma components from dissipating due to temperature rise, and preferable results can be obtained by keeping the temperature of the raw tea leaves at 40°C or lower, preferably 35°C or lower. The pulverized raw tea leaves are humidified during compression using pressure, mainly to facilitate the exudation of water-soluble components, but also to reduce the subsequent concentration of the exuded tea liquid and the loss of tea flavor components during drying. Since it is necessary for the tea liquid to be exuded to be thick, the degree of humidification is reduced as much as possible to obtain the tea liquid to be exuded. The moisture content of raw tea leaves after humidification is preferably 40% by weight or less.
25% by weight or less, and the temperature of the water for humidification is
The temperature is 40°C or lower, preferably 35°C or lower. Pulverized rock powder is added to humidified raw tea leaf powder to form a nearly homogeneous mixture. The rocks used mainly belong to the volcanic rocks such as rhyolite, andesite, and basalt, and should preferably contain no components harmful to hygiene and contain little iron, etc., which would harm the flavor of the tea, and should preferably be porous. . The particle size of the crushed rock used is 100 mesh or less, preferably 140 mesh or less. The amount of rock powder used is usually 1 to 2 times the weight of the raw tea leaves. The mixture of rock powder and raw tea leaf powder is pressed and squeezed by a conventional method to exude mainly water-soluble components in the raw tea leaves and absorb the exudate into the rock powder to be mixed. The pressure for squeezing varies greatly depending on the type and condition of the raw tea leaves, but is usually in the range of 2Kg/cm ² to 200Kg/cm ² , and it affects the flavor of the final product and the yield of tea components. It is desirable to establish the standard experimentally. Following the pressurization, the residue of the raw tea leaves is separated and removed. Separation of the rock powder that has absorbed mainly the water-soluble components of the tea leaves from the residue of the raw tea leaves can be carried out by a conventional method, such as a centrifugation method. Next, 0.5 to 2 times the weight of the original raw tea leaves with water at a temperature of about 40°C or less is added to the separated rock powder to elute mainly water-soluble components of the absorbed raw tea leaves, and then the rock powder is dissolved. A concentrated tea liquid stock solution can be obtained by separating and removing the powder, and a purified concentrated tea liquid can be further obtained by over-separating water-insoluble components. The obtained concentrated tea liquid is concentrated or dried by a conventional method to obtain the desired concentrated instant tea or powdered instant tea. Furthermore, the relationship between raw material tea leaf powder and volcanic rock powder will be explained in detail. Dry powder of raw tea leaves usually contains 5 to 6% by weight of water, and when it is humidified, the state is generally as follows. For example, when stirring to homogeneously humidify, the moisture content is approximately 25
Up to about 30% by weight, powder particles almost maintain a non-adhesive state even when pressurized, but when the water content exceeds about 30% by weight, they tend to stick together when pressurized, and the water content is about 40% by weight. When the water content exceeds about 70% by weight, it easily becomes a mochi-like shape when pressurized, and when the water content exceeds about 50% by weight, the fluidity gradually increases from a soft mochi-like shape to a paste-like shape when the water content is about 70% by weight. . On the other hand, volcanic rock powder not only has a large surface area, but is often porous to some extent, although it varies greatly depending on the type, and pumice such as rhyolite is particularly porous. Therefore, even if the porosity of volcanic rock powder is small, the amount of water adsorbed on the surface increases significantly due to the increase in surface area due to fine grain size, and when the porosity is large, the surface area increases due to fine grain size. Not only the increase, but also the increase in water absorption due to the pores is extremely large. For example, in the case of ordinary volcanic rock pumice, it is possible to absorb approximately 20 to 40% or more of water by weight. For tea leaf powder after humidification, such as one with a moisture content of up to about 30% by weight, when an appropriate amount of volcanic rock powder, for example 1 to 2 times the weight ratio, is added to the raw tea leaves and stirred, the volcanic rock powder and tea leaf powder are simply mixed. It doesn't stick at all just by applying it. In this case, the results are almost the same even if the porosity of the volcanic rock powder is small. When this mixture is squeezed under pressure to exude the tea ingredients together with water, if the porosity of the volcanic rock powder is small, the volcanic rock powder and the tea leaf residue tend to stick together to some extent; It can be easily crushed and separated using a machine. On the other hand, when using pumice powder, which is highly porous, for example, the pumice powder and tea leaf residue hardly stick together, and even if they do stick together, they can be easily separated into separate powders by stirring with a stirrer. This is to the extent that it is possible. In addition, when the moisture content of tea leaf powder exceeds about 30% and reaches about 50% and becomes sticky after humidification, the porous nature of the volcanic rock powder mixed with it is extremely advantageous. It is. When the porosity of the volcanic rock powder is small, the rock powder and tea leaf powder tend to stick together as the water content increases, especially after pressing. To avoid this, it is necessary to increase the amount of volcanic rock powder used, which is likely to result in a decrease in the yield of the final tea component. On the other hand, in the case of pumice powder, which is highly porous, even if the tea leaf powder sticks to each other after humidification, if you mix and stir the pumice powder, it will become an almost dry powder, and after the subsequent compression. Also, the pumice powder and the tea leaf residue can maintain the state of separate particles without sticking to each other, as in the case where the water content is about 30% or less. The above-mentioned difference in porosity of volcanic rock powder is that when the porosity is small, water is mainly absorbed as adsorbed water on the surface of the rock powder, whereas when the porosity is large, water is mainly absorbed by the large number of pores. It is presumed that water absorption is greatly increased by
The tea leaf powder that has become sticky due to humidification is mixed with pumice powder to dehydrate the tea leaf powder (at this point, most of the water-soluble components in the tea ingredients have already been eluted into the water). It can be said that the tea leaves have been dehydrated to such an extent that neither the tea leaf particles nor the rock powder stick to each other. Furthermore, when the moisture content of tea leaf powder is humidified to about 60% or more, it is usually necessary to use pumice powder as volcanic rock powder in an amount more than three times the amount of raw tea leaves. The behavior of tea components in tea leaf powder is estimated as follows. After adding water to the tea leaf powder and humidifying it evenly,
It is thought that most of the water-soluble components in the tea components are dissolved in the water contained therein. In addition, after mixing with volcanic rock powder, water on the particle surface and near the surface of the tea leaf powder (in both cases, the tea ingredients have already been dissolved)
is absorbed into volcanic rock powder. When a mixture of tea leaf powder and volcanic rock powder is pressed, the tea leaf powder is compressed between the volcanic rock powder, and soluble components dissolved therein are exuded together with the water contained therein. This exuded water is
It is immediately absorbed by volcanic rock powder that comes into contact with it.
At that time, components other than fibers among the tea leaf components are squeezed out from the tea leaf powder particles even if they are water-insoluble components or soluble components and are not dissolved in water at that time. It is considered that a part of the exudate is absorbed into the volcanic rock powder along with water, and the remaining tea leaf residue is dehydrated to the extent that it can be easily separated from the volcanic rock powder. This will be explained in more detail below with reference to Examples. In this example, 10 kg of green tea powder was used as a raw material, and % means % by weight, parts means parts by weight, and 10 parts corresponds to 1 kg. The raw material tea leaves used were powdered products equivalent to sencha green tea, and the properties such as quality and ingredients are shown in Table 1. Table 1 Properties and quality of raw tea leaf powder: Powder equivalent to medium sencha Green tea Approximate value of particle size distribution: Under 80 mesh sieve Particle size range (unit: microns) 100 fraction (%) 177-149 7 149-125 21 125 ~105 28 105~ 88 20 88 or less 24 Components; 100% ratio Moisture 6.1 Protein 24.2 Lipid 4.5 Carbohydrate 44.5 Sugar 30.3 Fiber, etc. 14.2 Ash 5.4 Caffene 2.4 Tannin 12.9 However, among the above components, the target component to be exuded as tea liquid is water. , the active ingredients of tea excluding lipids, fiber, etc., and the total is 75.2%. The raw material tea leaf powder is made by grinding tea leaves equivalent to sencha in a short time using a conventional method such as an impact grinder, keeping the temperature below 40℃, and then 80 mesh (aperture size).
Items listed in Table 1 that have passed through a sieve (177 microns)
After using 100 parts and charging the entire amount into a spiral blade stirrer (capacity 150, variable speed), the temperature is about 30℃.
After spraying and adding about 18.1 parts of water, stirring and evenly humidifying, to obtain about 118.1 parts of water with a water content of about 20.5%,
Next, 200 parts of separately prepared rhyolitic pumice powder belonging to volcanic rock that passed through a 140-mesh sieve (openings 105 microns) were gradually added and stirred thoroughly so that it was almost evenly distributed. and make a mixture. Table 2 shows the properties of the volcanic pumice powder used. Table 2 Properties and quality of volcanic pumice: Dried rhyolitic pumice powder Approximate value of particle size distribution: Particle size range under 140 mesh sieve (unit: microns) 100 part ratio (%) 105 to 88 160 88 to 74 29 76 - 63 27 63 or less 28 Density: approx. 2.6 g/cm ³ Bulk: approx. 1.0 g/cm ³ Porosity: approx. 0.38 Approximate values of components 100% ratio (%) SiO ₂ 74 Al ₂ O ₃ 14 Others 12 Next, this mixture is pressurized by a conventional method, for example, the entire amount is charged into a compression cylinder consisting of a bottomed cylinder and a piston with an inner diameter of 30 cm, and a water pressure machine with a pressurizing capacity of 150 tons is used to produce approximately 106 tons (approximately 150 Kg/cm ³ ). While maintaining the temperature, pressure is pressed for about 10 minutes to exude mainly water-soluble tea components from the raw tea leaf powder and absorb them into the pumice powder to be mixed. Next, the pressurized mixture is separated into pumice powder that has absorbed tea components and tea leaf residue using a conventional centrifugal separation method, such as a centrifugal air classifier consisting of a single cyclone, and only the former is collected, and 225.1 parts are collected. Obtained. Next, the pumice powder that has absorbed the tea components is heated to a temperature of approximately 30℃.
92 parts of water was added to make 317.1 parts, and the absorbed tea components were eluted by stirring thoroughly. Next, the entire volume is centrifuged using a conventional method, such as a bucket-type centrifugal dehydrator, to separate only the liquid.
After obtaining 136 parts of the concentrated tea liquid, the insoluble components are further removed from the mixed water to create a green and transparent concentrated tea liquid.
Obtained 133 copies. Concentrated tea liquid contains approximately 34% solids,
Its solids weight is approximately 45 parts. Therefore, this concentrated tea liquid has a tea composition of 93.9% after removing the moisture from the raw tea leaf powder.
It contains tea ingredients equivalent to about 48% of the active ingredients of tea, and about 60% of the active ingredients of tea, which are 75.2%. The composition of the concentrated tea liquid is shown in Table 3. Table 3 100% ratio (%) of the composition of concentrated tea liquid Moisture; 66.1 Protein; 12.3 Carbohydrate; 14.4 Ash; 2.9 Caffeine; 1.2 Tannin;
It is frozen to around -30°C on a tray, water is sublimated under a high vacuum of about 1 torr, dried, and then ground to obtain instant green tea powder. The resulting instant green tea powder has a moisture content of approximately 5%.
The amount is about 44 parts, and the tea component contains about 56% of the active ingredients compared to about 75% of the raw tea leaf powder. Its composition is shown in Table 4. Table 4 Composition of instant green tea 100% ratio (%) Moisture; 4.9 Protein; 34.5 Carbohydrate; 40.4 Ash; 8.2 Caffeine; 3.4 Tannin; 8.6 In this example, the unit of amount of raw material tea leaf powder used is weight. However, as long as this ratio is maintained, there is no problem in using other units such as Kg.
Further, the actual weight of the raw material tea leaf powder is preferably 5 kg or more. Further, the same procedure can be applied to black tea other than green tea. As mentioned above, the instant tea manufacturing method of the present invention uses inexpensive volcanic rock powder and takes advantage of its porous water absorbency, without using large amounts of hot water or solvents as in conventional methods. By having a structure in which the tea components of the raw tea leaf powder are once absorbed into the volcanic rock powder, it is possible to easily obtain a concentrated tea liquid. In addition, the temperature of the raw tea leaves and their exudate is kept below 40℃ throughout the entire process, so there is almost no dissipation of the flavor components of the tea due to temperature, and a large amount of tannins leaches out because they are leached out with low-temperature water. There is no bitterness, and since only a small amount of water is added to exude the tea ingredients, the resulting tea liquid has a concentration of more than 30%, which is extremely concentrated, compared to several percent when using conventional methods. Not only can it greatly reduce the amount of water removed during the concentration or drying process, which is the main cause of quality deterioration and cost increase, but it also greatly reduces the yield of tea components. As a result, it is possible to produce high-quality instant tea at a low price. Furthermore, the instant tea obtained has good flavor and color, is easily dissolved in water, warm water, or boiling water, and can yield a tea liquid with excellent flavor and color. Method: For example, if you use a teapot or the like to dissolve the first tea with water at an appropriate temperature, you can instantly prepare tea that has a flavor and light color that is equal to or better than freshly brewed tea by simply pouring water or hot water into it. It is something that can be obtained. Table 5 shows 6g of the instant green tea powder of the present application,
Using 30g of the unpowdered Sencha raw material used in the examples, each tea liquid was adjusted using 1000g of water at a temperature of 90℃, each made 10 cups of tea liquid, and 10 people tasted the average. The results and composition of The tea liquid of this application is light blue, compared to the tea liquid used as a control.
The taste was excellent, and the aroma was almost the same. In terms of component composition, the amount of protein and carbohydrates is almost twice that of the control tea liquid, which explains the excellent taste. The amounts of caffeine and tannins are about half, but the amounts can be increased or decreased as desired to suit your preferences.

[Table] Note: The control tea liquid was obtained after pouring hot water onto tea leaves and leaving it for 2 minutes.

Claims (1)

[Claims] 1 A mixture of crushed and humidified dry tea leaves added with crushed volcanic rock powder is pressed to exude mainly water-soluble components of the tea leaves and absorbed into the volcanic rock powder, and then extracted from the mixture. The volcanic rock powder is separated and water at a temperature of 40°C or less is added to elute the mainly water-soluble components of the tea leaves absorbed by the volcanic rock powder as a thick tea liquid, which is then filtered and dried. Instant tea manufacturing method to obtain tea powder.