JPS59125843A - Preparation of instant green tea - Google Patents

Abstract

PURPOSE:To prepare an instant green tea having excellent taste and flavor, by heat-treating the instant green tea powder prepared by conventional method from the extract liquid of tea leaves. CONSTITUTION:The tea leaves processed with a conventional tea-processing apparatus, preferably the tea leaves prepared by steaming raw tea leaves to inactivate the enzymes, cooling, and preliminarily heating at 35-50 deg.C for 10- 30min, or the tea leaves processed to the rough rolling stage or medium rolling stage, are extracted by conventional method. The extract liquid is filtered, concentrated and dried to obtain instant green tea powder having a water content of <=5%, and then secondarily heated at 70-120 deg.C for 10-120min under atmospheric pressure.

Description

[Detailed description of the invention]

It is well known that in the production of instant green tea powder, the extracted liquid from the finished tea leaves is concentrated into a powder, which does not provide instant green tea with excellent aroma and taste. A number of methods are known, including a method in which raw tea leaves are steamed to inactivate enzymes and then extracted, but it is difficult to obtain instant green tea that has the aroma, taste, and color that should be titrated. That is, when instant green tea is compared with regular green tea, instant green tea is usually of a lower quality. The cause of this is the extraction that makes instant green tea,
During the concentration and drying process, active ingredients may be lost or unpolished.
It is also well known that this is due to the generation of components. Further, it was generally considered that it was not preferable to further heat the instant green tea powder once produced or to oxidize it by bringing it into contact with air, as this would deteriorate the quality of the instant green tea. The present inventors extracted, filtered, concentrated,
It has been found that, contrary to expectations, the quality of instant green tea can be significantly improved by further heating dried instant green tea powder under certain conditions. That is, the present invention provides instant green tea powder dried to a moisture content of 5% or less and then dried at a temperature of 70 to 120°C.
This is a method for producing instant green tea with excellent flavor, which is characterized by heating for 10 to 120 minutes. It is presumed that the excellent effects of the present invention are due to the results of various studies. Tea confectionery made using the normal method has a perfect aroma and taste, but some flavor components still remain. During the production of instant green tea, these unfinished components are also extracted from the tea leaves. When exposed to excessive heat during the extraction, concentration, and drying processes in a high-moisture state, any of the components transforms into components that cause instant green tea to deteriorate rapidly; however, in low-moisture conditions (i.e., in a dry state), proper heating removes unfinished components. scent,
It has been revealed that it changes into a substance that is effective in taste, and does not convert into Hf, a finished component. The tea leaves used in the present invention can be any of coarse tea, finished tea, powdered tea, and leaf tea, as long as they are finished using regular tea manufacturing equipment, and also second- and third-grade tea leaves can be used to improve the effect. In the case of instant green tea made from tea leaves, it is possible to rank it as a high-grade tea through an inventive secondary heating process. Tea leaves that are particularly preferred as tea confections for use in the present invention are obtained by steaming raw tea leaves to inactivate the fermented tea leaves and then cooling them.
! It is preheated at -35 to 50°C for 10 to 30 minutes. Furthermore, the effects of the present invention can be more clearly achieved by using, as raw material, cut tea leaves that have been finished to the coarse or medium rolling stage using a conventional manufacturing facility.Next, Embodiments of the present invention will be described. (1) The raw material may be tea leaves completed by a normal manufacturing method or tea leaves that have been roughly rolled or medium rolled as described above.Alternatively, fresh leaves are preferably steamed. After inactivating the enzyme, the tea cake is preheated at 35-50'C for 10-30 minutes.

[It's a tea cake. As for the production method of such steamed tea confectionery, it is desirable to proceed to the steaming process immediately after harvesting. However, if the air is replaced with an inert gas and stored at around o'c, fresh leaves can be stored for about a week. Steaming involves removing heat with steam for about 1 to 2 minutes. By performing heat removal l-, the yield in the next extraction step is improved, and
Best point when the raw material tea is lower grade tea: Astringency in the product can be reduced. Shred the steamed leaves. To preheat, heat tea at a temperature of 35 to 50℃ for 10 to 30 minutes.
Heat for 0 minutes until the characteristic grassy smell of fresh leaves has almost completely disappeared and a slight aroma has emerged. Through this preheating, tea confectionery,
If the amount is about 35 to 65 of the weight of the steamed leaves. This preheating is an effective step in ensuring that the final product has desirable aromas and no undesirable aromas. Excessive preheating may give rise to undesirable aroma and taste in the final product, so care must be taken. (2) To obtain the extract from the cut pieces of the tea confectionery mentioned above, 1
00℃ or less, preferably 10 to 40℃ with hot water of 40 to 75℃
Extraction can be done in one step or in multiple steps per minute. (3) Filter the above extract with a filter. This is a necessary step to obtain a clear liquid when the final product is reconstituted with water or hot water. It is also effective in removing excessive astringency and other undesirable taste components when used as a lower grade tea leaf f or JfC ingredient. Filter pore diameter H0.6~1.0μm
is appropriate. The filter filtrate is concentrated under reduced pressure using a conventional method. The vacuum concentrate is dried by freeze drying or a spray dryer to a moisture content of 1 to 5 parts. (4) When the dried product is reconstituted with warm water, the reconstituted product has a desired color tone, but also contains aroma and flavor components to a desired degree (2). 120
[°C] o~12o min 1 tJJ secondary heating temperature, it was possible to produce a desirable taste and aroma components in a well-balanced manner. This secondary heating does not necessarily need to be performed under atmospheric pressure, and the same effect as under atmospheric pressure can be obtained under increased pressure or under IVl element. Secondary heating is not preferable if the temperature exceeds 120°C, as the product may melt or change in quality, and heating for more than 120 minutes is likewise not preferable. The most important thing to add to the extract concentration step: This is preferable for improving the quality of the product. The aromatic component may be a fresh leaf distilled aroma prepared by a conventional method, a single distilled aroma of preheated tea leaves, a distilled aroma of rough tea, finished tea, powdered tea, or dried tea, and these can be used as a type or two types. Furthermore, conjugating the above-mentioned distilled aroma to cyclodextrin is effective in preventing aroma loss in the next inversion step. Next, the present invention will be explained by examples. Example】. Panelists compared the quality of instant green tea produced by conventional methods and instant green tea produced by secondary heating. Instant green tea made by conventional method is Sencha IK, 7
(dry weight) in warm water at 65°C 61! Extracted for 2θ. The extract from which the tea leaves were separated was filtered through an fO06 μm filter and concentrated under reduced pressure at 50°C to obtain a concentrated solution with a solid content of 20%. Next, freeze drying (final product temperature 50°C)
), instant green tea with a moisture content of 2% was obtained. The yield was 30% based on the starting dried tea leaves. Secondary heating was performed under atmospheric pressure on a heated stainless steel plate (100° C.) for 40 minutes. The above instant green tea was compared with untreated instant green tea. For comparison, the above instant green tea powder 0.5y was used at 7
The taste, aroma, and color of the tea poured into 140 me of 5°C warm water were evaluated by seven panelists who are experts in tea identification. The results are shown below. Reasons why the product of the present invention is superior: No difference in taste of Shimoda 7
Name: 0 people Aroma: 7 people: 0 people: Color: 5 people: 2 people
Steamed for seconds. After quenching, the leaves were chopped and preheated. Preheating was carried out for 20 minutes at a pot temperature of 60°C and a leaf temperature of approximately 45°C. Q on the weight of leaves at the end of preheating
, 6Kg. The green odor of the leaves had almost disappeared and there was a slight fragrance. Next, 65°C warm water 4I! Extracted for 25 minutes. The once-extracted leaves were re-extracted with another hot water 21. Extracts of both (41 in total) f/-Toyo Roshi Filter TM
100 was used for pressure filtration. Then, the filtrate was heated to 50°C.
It was concentrated under reduced pressure to a concentration of 0.41. The concentrate was freeze-dried (finished product temperature: 50°C) to obtain a dry product weighing about 60 years (about 28% in terms of dry raw material tea). Next, the product was heated at 80° C. for 70 minutes in a freeze-turner that was returned to normal pressure. The results of a comparison between the obtained product and a regular Sencha product made from the same raw materials by expert panelists in the same manner as in Example 1 are shown below. If the product of the present invention is superior, If there is no difference, if it is inferior. Taste 5 people 2 people 0 people Aroma 1 person 4 people 2 people Color 0 people 6 people 1 person Overall 1 person 5 people 1 person Example 450 tea leaves taken out from a 3° coarse rolling machine? C Fresh leaf equivalent I kg
) was shredded and extracted with hot water 41 at 70°C for 15 minutes.
After filtration with a 6ym filter, it was concentrated under reduced pressure at 40"C and freeze-dried to obtain dry instant green tea (yield: 7% in terms of fresh leaf weight). Then, it was heated on a heated stainless steel plate under atmospheric pressure. , secondary heating was carried out at a product temperature of 85°C for 50 minutes.The product of the present invention was prepared in the same manner as in Example 1 using Sencha's instant green tea powder (without secondary heating) made from the same raw materials and by an expert panelist. The results of comparison are shown below. Those who found the product of the present invention to be superior Those who found no difference Taste: 5 people 2 people Aroma: 6 people 1 person Color: 3 people 4 people Overall: 6 people 1 person After steaming S1.5h for 2 minutes, the tea leaves were shredded and preheated for 25 minutes at a temperature of 1, which is a 50% reduction in fresh leaf weight, at a leaf temperature of 40°C.
! , 75°C, solid content of first stage extract is 1%, second stage 1 liter
o, 6%). Both were combined, filtered under pressure through a 0.6 μm filter, and concentrated under reduced pressure at 50°C to reduce the solid content to 13
It was a long time ago. 2 for 100y of preheated tea leaves prepared separately.
From the addition of 00 cc of water, 50 cc of aroma components were obtained from a vacuum distillation section at 50°C. 0.1y of β-cyclotetradextrin was added to this aroma component, and the tea leaves were left overnight to extract the zero aroma. The tea leaves were extracted in two stages under the above-mentioned conditions and added to the above-mentioned extract. The vacuum concentrate was divided into two equal parts, 50 cc of aroma component was added to one part, and no aroma component was added to the other part, and the two parts were freeze-dried separately to obtain instant green tea with a concentration of 6% in terms of fresh leaf weight. . Both samples were subjected to secondary heating at 80° C. for 60 minutes on a heated stainless steel plate under normal pressure. Evaluation using the same method as in Example 1 is as follows. Those with added aroma ingredients are said to be superior; those with no difference in taste
0 people 7 people Fragrance 7 people 0 people Color 01 people 7 people Overall
7 people 0 people

Claims (3)

[Claims] (1) Instant green tea powder with a moisture content of 5% or less obtained by filtering, concentrating, and drying the tea confectionery extract at 70 to 120°C.
A method for producing instant green tea with excellent flavor characterized by heating for 0 to 120 minutes. (2) The instant green tea according to claim 1, wherein the tea leaves are tea leaves obtained by steaming raw tea leaves to inactivate enzymes, cooling them, and preheating the tea leaves at a temperature of 35 to 50°C for 10 to 30 minutes. manufacturing method. (3) The method for producing instant green tea according to claim 1, wherein the tea leaves are tea leaves that have been finished to the rough rolling stage or medium rolling stage by a conventional method.