JPS6048138B2 - Instant green tea manufacturing method - Google Patents

Description

[Detailed Description of the Invention] It is well known that in the production of In-Stat green tea powder, converting the extracted liquid from the tea manufacturing industry into a concentrated powder does not produce In-Stat green tea with excellent aroma and taste. For this reason, various methods are known, such as directly extracting from raw tea leaves and extracting after steaming raw tea leaves to inactivate the enzymes. is difficult to obtain.

That is, when In-Stat green tea is compared with regular green tea products, In-Stat green tea is usually of a lower quality. It is well known that the cause of this is that active ingredients are lost or unnecessary ingredients are produced during the extraction, concentration, and drying processes that make In-Stat green tea. Further, it was generally considered that it was not desirable to further heat the In-Stat green tea powder once produced or to oxidize it by bringing it into contact with air, as this would deteriorate the quality of the In-Stat green tea. The present inventors unexpectedly improved the quality of in-situ green tea by further heating soluble powder tea extracted, filtered, concentrated, and dried from raw tea leaves processed under certain conditions. We have found that this can be significantly improved.

That is, the present invention steams raw tea leaves to inactivate the enzymes, cools them, preheats the tea leaves at a temperature of 35 to 500C for 10 to 3 minutes, and filters, concentrates, and dries the extract with hot water. Soluble powdered tea with a water content of 5% or less at 70-120°C for 10 minutes.
There is a method for producing in-stat green tea with excellent flavor, which is characterized by heating for ~120 minutes. As a result of various studies, it is estimated that the excellent effects of the present invention are due to the following reasons. Tea leaves finished using the normal method have a perfect aroma and taste, but some flavor components still remain. During the production of In-Stat green tea, these unfinished components are also extracted from the tea leaves.
In high moisture conditions, i.e., when subjected to excessive heat during the extraction, concentration, and drying processes, both components turn into components that make In-Stat green tea a nuisance, but in low moisture conditions, i.e., in dry conditions, proper heating can remove any of the components. It has become clear that the finished ingredients change into substances that are effective for aroma and taste, while the finished ingredients do not change. Next, embodiments of the present invention will be described. (1)
The raw material is tea leaves prepared by steaming fresh leaves to inactivate enzymes, cooling them, and preheating the tea leaves at 35 to 500 C for 10 to 30 minutes.

As for the production method of such steamed tea leaves, it is desirable to proceed to the steaming process immediately after picking. However, if the air is replaced with an inert gas and stored at around 0°C, fresh leaves can be stored for about a week. Steaming is done by deep steaming with steam for about 1 to 2 minutes. By performing deep steaming, it is possible to improve the yield in the next extraction step and to reduce the astringency in the final product when the raw material tea is a lower grade tea. To preheat the steamed leaves by shredding them, heat the tea leaves at a temperature of 35 to 50°C for 10 to 3 minutes, until the grassy odor peculiar to fresh leaves has almost disappeared and a slight aroma appears. By this preheating, the weight of the tea leaves becomes 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 cause undesirable aromas and tastes in the final product.
Caution must be taken. (2) To obtain an extract from the cut tea leaves mentioned above, the temperature should be 100'C or less, preferably 40-75C.
It may be extracted in one stage or in multiple stages for 10 to 4 minutes with warm water at ℃.

(3) Filter the above extract using 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 lower-grade tea leaves are used as raw materials. Filter pore size is 0.6-1.0
A value of μm is suitable. The filter filtrate is concentrated under reduced pressure using a conventional method. The vacuum concentrate is dried to a moisture content of 1 to 5% using freeze drying or a spray dryer. (4) When the dried product is reconstituted with hot water, the reconstituted product either has the desired color tone or lacks aroma and taste components to the desired extent.

The dried product is further heated to 70-1200C10-12 under atmospheric pressure.
By performing secondary heating, it was possible to produce desirable taste and aroma components in a well-balanced manner. This secondary heating does not necessarily have to be performed under atmospheric pressure, and the same effect as under atmospheric pressure can be obtained under pressurized conditions or oxygen. In addition, secondary heating is 120
If the temperature exceeds 12°C, the product may melt or change in quality, which is undesirable, and heating above 12 gin is also undesirable. (5) Furthermore, it is preferable to add an aroma component, which is a fragrance component, to the extraction liquid concentration step, if necessary, in order to improve the quality of the final product.

The aroma component may be a produced distilled aroma made by a conventional method, a distilled aroma of preheated tea leaves, a distilled aroma of coarse tea, finished tea, powdered tea, or violet tea, and one or two of these may be added. Furthermore, conjugating the distilled aroma to cyclodextrin is effective in preventing aroma loss in the subsequent drying process. Next, the present invention will be explained with reference to Examples.

Example 1 Second tea production 1 kg (wet weight) was heated with steam at 10@
Steamed for a while.

After quenching, the leaves were chopped and preheated. Preheating is at pot 60
The temperature of the leaves was kept at about 45°C for 2 minutes. The weight of the leaves at the end of preheating was 0.6 kg. The green smell of the leaves has almost disappeared and there is a slight fragrance. Then 6
Extraction was carried out for 25 minutes with 5°C warm water 4e. The once-extracted leaves were re-extracted with another hot water 2e. Both extracts (total 4'
) was filtered under pressure using Toyo Roshi Filter TMlOO. The filtrate was then concentrated under reduced pressure at 50'C to 0.4e. Freeze-dry the concentrate (final product temperature 50'C), approximately 6
A dried product of 0y was obtained (approximately 28% in terms of dry raw material tea). Next, at a product temperature of 80°C in a freeze dryer returned to normal pressure,
It was heated for 7 minutes. The obtained product was compared with a regular product of Tasencha made from the same raw materials by a specialist panelist in the same manner as in Example 1, and the results are shown below. Comparative Example 1 When the steamed tea leaves in Example 1 were preheated at a tea leaf temperature of 30°C for 2 minutes or 50°C for 5 minutes, the respective extracts with boiling water contained no tea aroma components. The soluble powder tea obtained by filtering, concentrating and drying these in the same manner as in Example 1 was unsuitable for use as instant green tea even after heating for 80'Cl7 minutes.

That is, the soluble powdered tea after heating was blue in color, had a strong grassy taste and odor, and had no tea aroma. Comparative Example 2 When the steamed tea leaves in Example 1 were preheated to 4 powders at a tea leaf temperature of 35°C or 2 powders at 60°C, each extract with hot water contained tea aroma components. However, the soluble powder tea obtained by filtering, concentrating, and drying these in the same manner as in Example 1 has a decrease in the original flavor of green tea and is not satisfactory. Ginma Netsusure is,
It had a burnt taste and a heated odor, and was ocher in color, which was not satisfactory as an instant green tea.

Example 2 After steaming 1.5k9 fresh green tea leaves for 2 minutes, the tea leaves were shredded and preheated at a leaf temperature of 40° C. until the weight of the fresh leaves was reduced by 50%.

Claims (1)

[Claims] 1 Steam the raw tea leaves to inactivate the enzymes, cool them, preheat the tea leaves at a temperature of 35 to 50°C for 10 to 30 minutes, filter the extracted liquid with warm water, concentrate, and dry the water 5 %
A method for producing instant green tea with excellent flavor, which comprises heating the following soluble powdered tea at 70 to 120°C for 10 to 120 minutes.