JP4598669B2 - Process for producing processed tea leaves using an extruder and an aqueous sugar solution - Google Patents

Description

  The present invention relates to a tea leaf processing method using an extruder and a processed tea leaf product. More specifically, the present invention relates to a technique for adding a sugar aqueous solution composed of water and sugar to tea leaves to make water-insoluble components of tea leaves water-soluble, thereby improving the natural natural flavor components of tea leaves in tea leaf extracts.

Conventionally, the technology for improving the natural umami component of tea beverages is described in Patent Documents 1 and 2, when the tea leaves are immersed in water, the temperature, pressure and time are controlled, and the water-soluble natural nature contained in tea leaves The extraction efficiency of umami components was optimized. However, according to Non-Patent Document 1, the water-soluble component contained in tea leaves is limited to around 40%, and thus there is a limit to the natural umami component obtained by the above method. Therefore, recently, as described in Patent Document 3, for example, by mixing finely ground tea leaves with the tea extract, a natural umami component of tea leaves that were not originally used for water-insoluble components was added. There is also a way to do it. However, since the natural umami component does not dissolve and is ingested as a solid, there is a drawback that it feels powdery and heavy due to fine pulverization and the refreshing feeling is impaired.
Patent No. 3447191 JP2001-286260 PCT / JP2004 / 008349 New tea industry book 8th edition, 1988 (Shizuoka Prefectural Tea Chamber)

  In such a background, the present inventors usually use an extruder that is used for the expansion and molding of cereals, and in addition to the hydrolysis reaction at high temperature and high pressure, is accompanied by pulverization and kneading action, and is water-insoluble. We paid attention to the point that the effect of lowering the molecular weight and water-solubility of the component could be obtained. According to the results of basic component analysis according to “Food of Japanese Food Standards, 5th edition, Science and Technology Agency, Resource Survey Committee, 2000”, tea leaves have a higher proportion of starch and fiber than grains such as brown rice and wheat. It is significantly different. Due to its characteristics, steam and raw materials usually squirt without being sufficiently kneaded and gelatinized. If a temperature condition that gives a sufficient reaction effect is given, the original damage of the tea leaves is significantly caused by heat damage. Extruder processing of tea leaves was considered unsuitable to reduce flavor quality. However, as a result of intensive studies to solve the above problems, the present inventors have relaxed the temperature condition rather than the processing condition for normal cereals, while increasing the pressure, thereby abundant in fiber. Even with tea leaves, it is possible to process the extruder, and it is possible to extract the natural umami ingredients inherent to tea leaves without causing heat damage to the tea leaves. Completed the invention.

  The subject of this invention is providing the technique which water-solubilizes the water-insoluble component of a tea leaf, and further improves the original natural umami component of the tea leaf in an extract, in order to further strengthen previous invention.

  For example, for tea leaves such as black tea, where it is customary to add sugar to the extract after drinking it and drink it, there is a problem as a manufacturing method even if the sugar is added together with water and processed by the extruder. Absent. Therefore, the present inventors have come to consider that by using an aqueous sugar solution instead of water in the previous invention, for example, a sugar-amino reaction or the like acts and further enhancement of the effect is expected.

  The present inventors have found that by adding an aqueous sugar solution at the time of extruder processing, it is possible to extract the natural umami component inherent to tea leaves more than the previous invention in which only water was added. The inventors have found that the effect depends on the concentration and type of sugar and completed the present invention.

  That is, in the method of the present invention, the tea leaves are extruded under conditions of 80 to 150 ° C., 0.2 to 30 MPa, and 5 to 600 seconds, while supplying an aqueous sugar solution at 1 to 100 weights with respect to 100 weights of tea leaves, The present invention relates to obtaining a processed tea leaf stably without being ejected from an outlet.

  In general, tea leaves refer to general tea leaves including unfermented tea (green tea), semi-fermented tea (oolong tea), fermented tea (black tea), etc. As green tea, sencha, stem tea, bancha, Gyokuro, mochi tea, kettle roasted tea and the like. Here, strictly speaking, stem tea does not use leaves as raw materials, but tea beverage raw materials are treated as raw materials equivalent to tea leaves and are therefore included in tea leaves in this specification. However, grain tea containing a large amount of starch, such as pearl barley tea, is excluded from the tea leaves of the present invention.

  Furthermore, the tea leaves in the present invention are not only those dried as normal tea leaves, but are defined in any state from the fresh leaves picked in the tea plantation to the finished tea leaves as described above. is there. Specifically, tea leaves immediately before plucking that have not undergone the enzyme deactivation process by steaming or kettle roasting, or after the steaming or kettle roasting process, before and after the process of evaporating moisture while smoldering called koji Even so, it is a tea leaf as defined in the present invention. These can be used alone or in admixture of two or more in the method of the present invention.

  Of the above raw materials, green tea or black tea is more preferable in the present invention. Since the processed tea leaf product obtained by the method of the present invention retains sugar as it is after drying, tea leaves such as black tea that have a custom of adding sugar when drinking are the most preferred raw materials, but when drinking Even for tea leaves that do not have the custom of adding sugar, it will be possible to provide a new type of processed tea leaves by using it as a raw material for the method of the present invention. As an application of the present invention, the use of tea leaves with improved natural umami ingredients, such as strawberry tea and gyokuro, creates a processed tea leaf product with further improved natural umami ingredients due to the combination effect. You can also Conversely, by using this technology for tea leaves with few natural umami ingredients, such as sencha using Nibancha and Sanbancha, and stem tea, it is possible to create tea leaves that are excellent in natural umami ingredients at low cost. Is possible.

  In the present invention, the state of the tea leaves before being supplied to the extruder is not particularly limited, and it may be in a raw state, a dried state, a pulverized state, or an unpulverized state. Good. When pulverized, the degree of pulverization is not particularly limited, and it may be coarsely pulverized or finely pulverized by a roller mill or the like.

  In the present invention, an extruder is usually a cylinder called a cylinder, which is used for the purpose of expanding and molding cereals, etc., and is usually equipped with a rotating screw. At the same time, the raw material is supplied, pulverized and mixed, and then discharged from the other hole. The starch that has been gelatinized due to the pressure difference before and after the discharged hole expands, producing a food-rich snack, etc. To get. From the viewpoint of workability and operability, for example, a twin screw extruder for food (TEX30FC-18.5PW-V) manufactured by Nippon Steel Co., Ltd. is preferable, but it is limited to this. Instead, a normal 2-axis type extruder and a 1-axis type extruder can be used as well. That is, the parameters of the extruder, such as the screw structure and the rotation speed thereof, are not particularly limited as long as the temperature, pressure, time, and water addition amount described in detail below are satisfied.

  In the present invention, the term “extruder processing” means that the raw material is supplied together with water from one of the cylinders using the above-mentioned extruder, pulverized and mixed, and discharged from the other hole.

  The processing temperature is not particularly limited as long as the maximum temperature inside the cylinder is 80 to 150 ° C. In the present invention, the temperature is preferably 80 to 130 ° C, and particularly preferably 85 to 120 ° C. If it is less than 80 ° C., the effect of solubilizing the natural umami component is small, and if it exceeds 150 ° C., the water-soluble natural umami component may be lost due to heat damage.

  The processing pressure is not particularly limited as long as the maximum pressure inside the cylinder is 0.2 to 30 MPa. In the present invention, the pressure is preferably 0.2 to 20 MPa, and particularly preferably 0.6 to 15 MPa. If it is less than 0.2 MPa, the effect is small, and a pressure exceeding 30 MPa is not preferable from the viewpoint of workability and operability.

  The processing time is not particularly limited as long as the residence time in all cylinders is 5 to 600 seconds. In the present invention, it is preferably 10 to 120 seconds, and particularly preferably 20 to 60 seconds. If it is less than 5 seconds, there is little water-soluble effect of the natural umami component, and if it is longer than 600 seconds, the natural umami component extracted when the temperature is high may be lost due to heat damage. Absent.

  In the present invention, the aqueous sugar solution is a mixed solution of sugar and water, and the sugar does not have to be dissolved in water at room temperature in consideration of mixing with tea leaves under high temperature and high pressure conditions in extruder processing. The water here will be described in detail below. The sugar as used herein refers to a polyhydric alcohol having an aldehyde group (—CHO) or a ketone group (C═O). Regardless of the number of carbons that form the member ring or the total number of carbons that make up the molecule, deoxy sugars in which the hydroxyl group of the sugar is replaced with hydrogen, uronic acid in which the aldose terminal carbon is replaced with a carboxyl group, and the hydroxyl group as an amino group Substituted amino sugars, sugar alcohols in which ketone groups or aldehyde groups have been reduced to alcohol are also included in the sugar of the present invention. The sugars of the present invention include all optical isomers such as D-type and L-type, sugars having a chain structure and a cyclic structure, and sugars such as α-type and β-type classified in the cyclic structure.

  Representative monosaccharides include glucose, fructose, galactose and the like. A disaccharide is a monosaccharide resulting from two monosaccharide molecules resulting from a glycosidic bond. Examples of typical disaccharides include maltose, lactose, and sucrose. A combination of 3 to 10 monosaccharides is called an oligosaccharide. Typical oligosaccharides include fructooligosaccharides, galactooligosaccharides, palatinose, kestose, raffinose, maltotriose, etc. Including those marketed under the name Further, a combination of many monosaccharides is called a polysaccharide, and typical polysaccharides include starch, cellulose, pectin and the like. Moreover, what is generally called a water-soluble dietary fiber, such as dextrin, is also contained in the polysaccharide here. The sugar used in the present invention may be any of the sugars described above, but is preferably a disaccharide or a monosaccharide, and more preferably a monosaccharide. These sugars can be used alone or in admixture of two or more.

  The water solubility of the sugar used in the present invention is not particularly limited, but from the viewpoint of preventing the extruder from being clogged, a sugar that is water soluble under the conditions of the extruder processing in the method of the present invention is preferred.

  In consideration of extracting and drinking the processed tea leaf product obtained by the method of the present invention, the sugar used in the present invention is generally a edible sugar. In addition, when it is desired to impart sweetness to the processed tea leaf product, a desired tea leaf processed product can be easily obtained by using a sugar that exhibits sweetness.

  In addition, the water used for processing in the present invention does not contain any water or impurities normally used in food processing from the viewpoint of dehydrating water-insoluble components and extracting natural umami components without adding an enzyme agent or the like. Pure water is preferred, but if necessary, if there are substances that are effective for extracting the natural umami ingredients of tea leaves, such as alcohol and salts, it may be added, especially for pure water. It is not something.

  The mixing ratio of sugar and water in preparing the aqueous sugar solution is not particularly limited, but the concentration of the aqueous sugar solution is 0.01% to 38%, preferably 2 to 35%, more preferably 10 to 30%. In this specification, the concentration of the aqueous sugar solution is expressed by weight%. For example, a 20% aqueous sugar solution is prepared from 20 parts by weight of sugar as described above and 80 parts by weight of water as described above. Refers to the solution.

  The addition amount of the aqueous sugar solution in the method of the present invention is not particularly limited as long as it is 1 to 100 wt. In the present invention, the weight is preferably 3 to 80 weights, more preferably 5 to 65 weights, and particularly preferably 10 to 40 weights. If it is less than 1 weight with respect to 100 weight of tea leaves, sufficient natural umami component water-solubilizing effect will not be obtained, and if it exceeds 100 weight, the fluidity of the tea leaves supplied into the cylinder will increase. This is too much and causes troubles in extruder processing, such as intense eruption.

  The present invention also has a water-soluble protein content of 0.1% or more, preferably 1% or more, more preferably 4%, compared to a processed tea leaf product that has been subjected to extruder processing by adding water that does not contain sugar to tea leaves. As described above, a method for producing a processed tea leaf product by extruding the tea leaf by adding 1 to 100% of an aqueous sugar solution to 100 wt. provide.

In the present specification, “compared with processed tea leaves obtained by adding water that does not contain sugar to tea leaves” is used in the method of the present invention to use an aqueous sugar solution at the time of extruder processing. Instead, it means that a processed tea leaf product obtained by making all the processing conditions other than the use of a solution containing no sugar is compared with the processed tea leaf product obtained by the method of the present invention.

The present invention also increases the amount of water-soluble protein contained in tea leaves by kneading an aqueous sugar solution and tea leaves at a temperature of 80 to 150 ° C. and a pressure of 0.2 to 30 MPa, and thereafter By extracting tea from a tea leaf with a solvent such as water, there is provided a method for producing a tea extract having an improved taste compared to extraction from tea leaves obtained by kneading sugar-free water and tea leaves during the kneading.

  Here, “tea leaves obtained by kneading water and tea leaves that do not contain sugar during the kneading” means conditions for kneading other than using water that does not contain sugar instead of using an aqueous sugar solution during the kneading. Refers to tea leaves obtained by equalizing all. The solvent such as water is any solvent suitable for tea extraction, preferably an aqueous solvent. The temperature may be any temperature as long as tea extraction is possible.

  In the present specification, the water-soluble protein content is one that can be measured by a technique known to those skilled in the art, more specifically, one that can be measured using the technique described in Example 1. Point to. If the water-soluble protein content is high, natural umami components drawn into the extract increase, and it is considered that the processed tea leaf product is preferable in terms of taste. Note that the composition of the water-soluble component also affects the taste.

  According to the method of the present invention, the processed tea leaves discharged from the extruder outlet are not in a swollen state as in the case of foods containing a large amount of starch, and are typically continuously connected smaller than the volume before processing. Discharged in a state. The thickness of the processed product at the time of discharge depends on the diameter of the extruder outlet hole, but there is no special restriction. For example, it is preferable to use an outlet hole with a diameter of 2 mm or more. In that case, considering the slight expansion when discharged from the outlet hole due to the presence of starch contained in tea leaves, Thickness can be greater than 2mm. This may be cut at an arbitrary length and taken out as a stick-like processed product, or may be taken out as a granular processed product by means such as a rotary blade attached to the outlet, and the shape of the tea leaf processed product is not particularly limited . In particular, when producing a tea bag or a liquid tea extract, a granular processed product is preferable from the viewpoint of facilitating extraction.

  In this way, the processed tea leaf product of the present invention from which the natural umami component inherent to the tea leaf is extracted can be stored in a silo or the like after cooling and drying (vacuum drying, hot air drying, etc.). it can. The moisture content of the dried tea leaf product after drying is preferably 10% or less, more preferably 5% or less.

  The tea leaf processed product from which the natural umami component originally derived from tea leaves in the present invention is extracted can be used with tea leaves, liquid tea extract, etc. as one of the tea ingredients of tea beverages, and is manufactured at a tea beverage manufacturing factory by a conventional method. can do. For example, taking a tea beverage can manufacturing process as an example, it can be manufactured through the steps of “extraction”, “filtration”, “preparation”, “filling”, “clamping”, “sterilization”, “cooling”, and “boxing”. For those which cannot be sterilized by retort, such as PET bottles and paper containers, after sterilization in advance under the same sterilization conditions as above, a method such as cooling to a certain temperature and filling the container is adopted.

  As a suitable embodiment in the practice of the present invention, a tea bag or a liquid tea extract may be prepared using the processed tea leaf product of the present invention. Sugar will adhere to the processed tea leaves processed from the method of the present invention. Therefore, for example, using a processed tea leaf product obtained by processing black tea by the method of the present invention, it is possible to produce a unique tea tea bag that has sweetness without adding sugar such as sugar after extraction. It becomes.

  According to the method of the present invention, it is possible to provide a processed tea leaf product having an improved water-soluble protein content, and to extract a natural umami component more than the processed tea leaf product by the extruder processing using water not containing sugar. Was suggested. In addition, since the processed tea leaf product obtained by the method of the present invention retains the added sugar as it is after drying, the tea leaf processed product extract contains not only the natural natural umami components inherent in tea leaves but also moderate sugar-derived ingredients. You can also feel the sweetness.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these.

Example 1
Extruder processing of the present invention was performed using Sri Lankan black tea as raw tea leaves. Specifically, as extruder processing, tea leaves were supplied from the raw material hopper at the top of the cylinder and supplied to the cylinder at a constant rate of 40 kg / H. On the other hand, monosaccharides [fructose butter sugar liquid sugar (fructose + glucose), "F55 (fructoca)" Kato Chemical Co., Ltd.], disaccharides [sugar (sucrose), "granulated sugar CIM2" ITOCHU Sugar Co., Ltd.], Oligosaccharides [fructo-oligosaccharides, “Mayoligo P (Liquid)” Food Materia Co., Ltd.], water-soluble dietary fiber [digestible dextrin, “Pine Fiber” Matsutani Chemical Co., Ltd.], dissolved in pure water The prepared sugar aqueous solution having a concentration of 20% was supplied to the same cylinder at a constant rate of 10 kg / H from another supply port. The electric heater attached to the outside of the cylinder was controlled so that the maximum temperature inside the cylinder would be 95 ° C, and the screw structure and rotation speed were adjusted so that the maximum pressure inside the cylinder would be 1.5 MPa. Furthermore, when the residence time in a cylinder was measured using the red coloring agent which is a food additive, it was 45 seconds. When the above processing conditions are continuously operated for several hours, the dispersion of each measured value becomes constant, and when the steady operation state is reached, the blade attached to the outlet is rotated at 1000 rpm, the outlet workpiece is cut, and the granular tea leaves are processed. I got a product.

  Extract the processed tea leaves and the processed processed tea leaves under the same conditions by adding pure water, and extract and filter 1g each with 100ml of pure water at 80 ° C for 30 minutes. An extract was obtained. As an evaluation method, the water-soluble protein content (mg / g-raw material) in each extract was measured by the Coomassie method (wavelength 595 nm). FIG. 1 shows a comparison of the results with the control product extract as 100.

  As is clear from FIG. 1, the water-soluble protein in the processed product extract increased with the exception of the water-soluble dietary fiber, compared to the control product extract. And it was found that the smaller the number of sugar bonds, the higher the rate of increase. In addition, since this processed product is considered to be different in the principle of obtaining water-soluble protein from the method of the control product, the type and composition of the water-soluble protein in the extract of this processed product are also different. Even so, it is thought that the influence on sensory evaluation will increase.

Example 2
Extruder processing of the present invention was performed using green tea from Shizuoka as raw tea leaves. Specifically, as extruder processing, tea leaves were supplied from the raw material hopper at the top of the cylinder and supplied to the cylinder at a constant rate of 40 kg / H. On the other hand, a sugar solution having a glucose concentration of 20%, 40%, and 60% was supplied to the same cylinder at a constant rate of 10 kg / H from another supply port. The electric heater attached to the outside of the cylinder was controlled so that the maximum temperature inside the cylinder would be 95 ° C, and the screw structure and rotation speed were adjusted so that the maximum pressure inside the cylinder would be 1.5 MPa. Furthermore, when the residence time in a cylinder was measured using the red coloring agent which is a food additive, it was 45 seconds. When the above processing conditions are continuously operated for several hours, the dispersion of each measured value becomes constant, and when the steady operation state is reached, the blade attached to the outlet is rotated at 1000 rpm, the outlet workpiece is cut, and the granular tea leaves are processed. I got a product.

  Extract the processed tea leaves and the processed processed tea leaves under the same conditions by adding pure water, and extract and filter 1g each with 100ml of pure water at 80 ° C for 30 minutes. An extract was obtained. As an evaluation method, the water-soluble protein content (mg / g-raw material) in the extract was measured by the Coomassie method (wavelength 595 nm). FIG. 2 shows a comparison of the results with the control product extract as 100.

  As is clear from FIG. 2, the amount of water-soluble protein in the processed product extract obtained using a 20% glucose aqueous solution increased compared to the control product extract. And it was found that the numerical value decreased as the concentration of sugar in the sugar solution increased to 40% and 60%.

Example 3
Extruder processing of the present invention was performed in the same manner as in Example 1 using Assam black tea leaves as raw tea leaves, and tea bags in tea bags were produced from the obtained tea leaf processed products. Specifically, a CTC machine (a tea leaf passes through the gap between two stainless steel rollers, the tea leaf is crushed by the rotation of the roller, it is crushed, the tea leaf is split by the protrusions attached to the roller surface, and it is engraved diagonally Machined using a machine in which the tea leaves are rounded and shaped into a spherical shape in a groove, and then wrapped in a fine paper bag. The tea bag using the processed tea leaf product of the present invention is put in a tea cup, extracted by pouring hot water, and the resulting tea is tasted. As a characteristic of the tea with a normal tea bag, it is relative to the overall balance. Ingredients such as bitterness, tannins, and caffeine, which tend to be felt strongly, were felt relatively mellow, giving the impression that the overall balance was well-balanced.

In Example 1, it is a graph which shows the result of having examined the kind of sugar in the sugar aqueous solution in the extruder process of a tea leaf. In Example 2, it is a graph which shows the result of having examined the density | concentration of glucose in the sugar aqueous solution in the extruder process of a tea leaf.

Claims (8)

The maximum temperature in the cylinder during extruder processing is 80 ℃ ~ 150 ℃,
The maximum pressure in the cylinder during extruder processing is 0.2 MPa to 30 MPa,
A method for producing a processed tea leaf product by adding 1 to 100 weight sugar aqueous solution to 100 weight tea leaf and extruding the tea leaf. To tea by adding water to a sugar-free as compared to the tea leaves workpiece subjected to extruder processing, characterized in that the water-soluble protein content obtained 0.1% or more higher have tea workpiece, tea leaves 100 wt On the other hand, a method for producing a processed tea leaf product by adding 1 to 100 wt. The method according to claim 1 or 2, wherein the concentration of the aqueous sugar solution is 0.01% to 38 % . Sugar wherein the sugar in the aqueous solution, a monosaccharide, disaccharide or oligosaccharide, the method according to any one of claims 1 to 3.   A processed tea leaf product produced by the method according to any one of claims 1 to 4.   6. A tea beverage produced by extracting the processed tea leaf product of claim 5 with a solvent.   6. A food or drink containing the processed tea leaf product of claim 5 or a solvent extract thereof. By kneading the aqueous sugar solution and tea leaves at a temperature of 80 to 150 ° C. and a pressure of 0.2 to 30 MPa, the amount of water-soluble protein contained in the tea leaves is increased compared to before kneading,
Then, by extracting tea from the tea leaves with a solvent such as water,
A method for producing a tea extract having an improved taste compared to extraction from tea leaves kneaded with sugar-free water and tea leaves during the kneading.

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