JPH0360467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing cold water soluble tea products and more particularly to powdered tea extracts that are easily and completely soluble in cold water.

Conventional instant tea production methods, which usually consist of extraction, aromatization, haze removal and drying steps, do not provide cold water soluble powders. Achieving cold water solubilization requires some additional processing of the brewed tea, which contains significant amounts of cold water insoluble materials formed by tea cream and polyphenol polymers. This additional method cools the hot water tea extract and
It involves precipitating cold water insoluble substances, or it involves solubilizing cold water insoluble substances with chemicals or enzymes. However, in the former method there is a loss of up to about 10% of total tea solids when the sediment part is discarded, and in the latter method the reconstituted beverage is very foamy and has poor stability, edibility and potability. Sexuality is extremely inadequate.

One method for producing cold water soluble tea extracts that does not involve the use of any additives is described in British Patent No. 559,758. In this method, a cold water extract of dried tea is produced at a temperature of 10-25°C, and then the same tea leaves are used again for the production of a hot infusion with boiling or almost boiling water, and both extracts are mixed in the desired proportions. The extract is dehydrated to produce a semi-liquid or solid extract that is mixed with the extract. However, the disadvantage of such a method is that the time required for cold water extraction is quite long, e.g.
~24 hours is what is stated. Such extraction times are not economically viable.

It has been found that cold water soluble tea powder can be produced from tea leaves by a very simple method without the use of chemicals or enzymes. This method involves macerating, cold water extraction and then hot water extraction, in which 4
Longer cold water extraction times are unnecessary and neither tea cream formation nor polyphenol polymerization occurs.

Therefore, the present invention provides a powder in which black tea leaves are macerated with water, the macerated leaves are first extracted with cold water and then with hot water, and after this the cold water and hot water extracts are mixed before concentration and drying. A method for producing a tea extract is provided.

The method of the invention can be applied to all types of black tea and mixtures thereof.

To soften tea leaves, use cold or hot water, e.g. 15-40℃,
Preferably, it can be carried out at 20 to 35°C. The swelling time should be sufficient to obtain good wetting of the tea leaves and is usually at least 20 minutes, such as 40 to 150 minutes, advantageously 50 to 130 minutes. Times longer than 150 minutes can be used, but are unnecessary as they do not result in any improvement in the final product. Advantageously, the macerating process can be carried out at ambient temperature, for example 20-30°C. The macerating process softens and swells the tea leaves, facilitating cold water extraction and increasing productivity. The water is advantageously deionized water. The amount of water used for swelling is from 0.5 to 10 parts by weight, advantageously from 1 to 5 parts by weight, preferably from 1.5 to 3.5 parts by weight, based on the weight of the tea leaves.

The macerated soft tea is then extracted in batches or countercurrently.
Batch extraction is preferably carried out in a container containing water and tea leaves while stirring.
In the countercurrent method, water flows countercurrently through a number of cells containing tea leaves.

For extraction with cold water, the water temperature is between 10 and 40 °C, preferably
The temperature is between 15 and 35°C, especially between 20 and 30°C. The cold water extraction time is up to 2 hours, for example 2.5 to 90 minutes, advantageously 4 to 80 minutes. For both countercurrent and batch methods, extraction times of 5 to 45 minutes are suitable, preferably 7.5 minutes.
~35 minutes, although in batch processes the extraction time may be extended to 50-75 minutes if desired. The water is advantageously deionized water. The amount of water used for cold water extraction is between 2 and 50 parts by weight, preferably between 5 and 30 parts by weight of the tea leaves.
Preferably it is 7.5 to 25 parts by weight. After extraction, the cold water extract is separated from the tea leaves.

In hot water extraction, the water is at a temperature of 60-100°C, preferably 65-97.5°C, especially 70-95°C. Hot water extraction time up to 15 minutes, advantageously from 2.5 to 12.5 minutes,
Preferably it is 5 to 11 minutes. The amount of water used for hot water extraction is between 2 and 50 parts by weight, preferably between 5 and 30 parts by weight of tea leaves.
parts by weight, preferably 7.5 to 25 parts by weight. Advantageously, the amount of water used for hot water extraction is approximately the same as the amount of water used for cold water extraction. In the batch process the hot water is advantageously poured over the tea leaves, while in the unidirectional flow process the hot water advantageously flows through a number of cells containing tea leaves previously extracted with cold water. After hot water extraction, the extract is separated from the tea leaves.

After both cold water and hot water extraction, the method for separating the extract from the tea leaves is either a batch method or a countercurrent method. In batch processes, separation is suitably carried out by filtration or centrifugation; in unidirectional flow processes, separation is achieved by draining the extract from the cell containing the least extracted tea leaves.

Advantageously, the separated hot water extract is treated with activated carbon before being mixed with the cold water extract. For example, activated carbon is 2 to 50% by weight, preferably 5% by weight, based on the weight of dry tea leaves.
It is added to the extract in an amount of ~30% by weight, especially 10-20% by weight. The mixture is stirred for a suitable period of time, preferably from 5 to 20 minutes, before separating the hot water extract from the activated carbon, for example by filtration or centrifugation. Alternatively, the hot water extract is forced through a column containing activated carbon. The amount of activated carbon is, for example, 1 to 60 minutes, preferably 5 to 60 minutes.
The amount is sufficient to guarantee a contact time with the hot water extract of 30 minutes, especially 10-15 minutes.

This treatment with activated carbon further improves the inhibition of the formation of cold water insoluble substances formed by tea cream and polyphenol polymers.

The activated carbon is washed with hot water to minimize solids loss and regenerated, for example by heating or solvent washing.

The cold water and hot water extracts are then mixed and the extract is generally concentrated to the desired solids content before drying, for example by freeze drying or spray drying.

The powder extract contains any ingredients normally used in tea products, such as sucrose, glucose, citric acid, tartaric acid,
Mixed with flavor and anti-caking agent.

The powder extract obtained according to the invention then dissolves instantly in cold water at 15-20°C, which can be ice-cooled, providing a beverage with good stability, eating and drinking quality.

The following examples further illustrate the invention.

Example 1 20 kg of deionized water at 25°C was poured into a container containing 10 kg of black tea leaves and allowed to swell and soften for 60 minutes. Thereafter, 200 g of deionized water at 25° C. was poured over the expanded soft tea leaves, and the mixture was extracted for 10 minutes with stirring. The cold water extract was then separated by centrifugation.

Then 85°C deionized 200 ml of cold water extract was poured onto the separated spent tea leaves and the mixture was extracted for 10 minutes. The hot water extract was then separated by centrifugation.
The cold and hot water extracts were mixed together and passed to the evaporator. The mixed extract was then concentrated and finally spray dried to obtain a powder extract that was instantly soluble in cold water.

Example 2 By the same procedure as described in Example 1, but with 20
By using 30Kg of deionized water instead of Kg and macerating 10Kg of tea leaves for 120 minutes instead of 60 minutes,
A powder extract was obtained which dissolved instantly in cold water.

Example 3 By the same procedure as described in Example 1, but by extracting with cold water for 60 minutes instead of 10 minutes, a powdered extract was prepared that was instantly soluble in cold water.

Example 4 By the same procedure as described in Example 1, but by using 100 of water in both the cold and hot water extractions instead of the 200 used therein, a powdered extract was produced that was immediately soluble in cold water. .

Example 5 25Kg of deionized water at 25°C was poured into a container containing 10Kg of black tea leaves and then left to soften for 90 minutes. then 25℃
150 ml of deionized water was poured over the softened tea leaves and the mixture was stirred for 30 minutes before being extracted. The cold water extract was then separated by filtration.

Then 150 g of boiling deionized water was poured over the spent leaves from which the cold water extract had been separated, and the mixture was extracted for 10 minutes. Next, the hot water extract was separated by filtration, and 15% by weight of activated carbon was added to the hot water extract based on the weight of dry tea leaves. The mixture was stirred for 10 minutes and then filtered. The cold water extract was mixed with the hot water extract separated from the activated carbon, concentrated to a suitable solids content, and finally spray dried to obtain a powder extract that was instantly soluble in cold water.

Comparative Example A 10 kg of black tea leaves that were not softened were extracted with 200 ml of deionized water at 25° C. while stirring for 10 minutes. The cold water extract was separated by filtration. Then 200 mL of deionized water at 85°C was poured over the spent leaves and the mixture was extracted for 10 minutes, after which the hot water extract was separated by filtration.
The two extracts were dehydrated to a powder and then mixed, but the resulting mixture did not completely dissolve in cold water.

Comparative Example B The same procedure as described in Comparative Example A was followed, but
The hot and cold water extracts were mixed before being dehydrated and powdered. The resulting powder did not completely dissolve in cold water.

Comparative Example C The same procedure as described in Comparative Example A was followed, but
Cold water extraction time was 4 hours instead of 10 minutes. The product mixture did not completely dissolve in cold water.

Claims (1)

[Claims] 1. In a method for producing powdered tea extract, black tea leaves are swollen and softened with water, the swollen soft leaves are first extracted with cold water, then with hot water, and then extracted with cold water and hot water before concentration and drying. The above-mentioned manufacturing method, which comprises mixing a hot water extract. 2. The method according to claim 1, wherein the swelling time is 40 to 150 minutes. 3 The amount of water used for swelling is 1.5 per part by weight of tea leaves.
3. A method according to claim 1, characterized in that the amount is ~3.5 parts by weight. 4. The method according to claim 1, characterized in that the cold water extraction time is 7.5 to 35 minutes. 5 The amount of water used for cold water extraction is per part by weight of tea leaves.
Process according to claim 1, characterized in that the amount is 7.5 to 25 parts by weight. 6. The method according to claim 1, characterized in that the water temperature for hot water extraction is 60 to 100°C. 7. The method according to claim 1, characterized in that the hot water extraction time is 5 to 11 minutes. 8 The amount of water used for hot water extraction is per part by weight of tea leaves.
Process according to claim 1, characterized in that the amount is 7.5 to 25 parts by weight. 9. Process according to claim 1, characterized in that the hot water extract is treated with activated carbon after separation from the tea leaves and before mixing with the cold water extract. 10. The method according to claim 1, characterized in that the cold water and hot water extracts are mixed immediately before concentration. 11 Claim 1, characterized in that the water used for both swelling and extraction is deionized water.
The method described in section.