JP2540719B2 - Tea leaves - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to tea leaves which can withstand long-term storage by spraying or applying a water-soluble compound derived from chitin.

[0002]

2. Description of the Related Art Conventional tea leaves that are commercially available in the past have been dried to a water content of 3.5% or less, and after purchase, such tea leaves are damp. Had to save so as not to.

[0003]

However, when the storage condition is bad, the tea leaves are rapidly humidified,
Tea extracted using dried tea leaves has a fragrance,
It was inferior in taste and the like, and even if it was stored in a good environment, it gradually absorbed moisture, and it was difficult to store it for a long period of time.

Further, if it is difficult to store for a long period of time as described above, it is impossible to make a bulk purchase, and a plurality of purchases are forced in a short period of time, which is troublesome.

Further, recently, vacuum packaging and packaging bags having excellent airtightness have been developed, and although these bags are kept dry until they are opened, they are opened. Depending on the storage condition or storage period after that, it absorbs moisture as described above.

The present invention has been made in view of the above points, and an object of the present invention is to provide a tea leaf which can withstand long-term storage.

[0007]

In order to achieve the above-mentioned object, the present invention is characterized in that a water-soluble compound derived from chitin is attached to the surface by spraying or coating. Leaves are the gist.

[0008]

[Effect] As described above, since the water-soluble compound derived from chitin has a chemical structure similar to cellulose, spraying this compound on tea leaves covers the tea leaves with a transparent film. Like For this reason, it is possible to prevent the moisture absorption of the tea leaves, and it is possible to prevent the tea leaves from getting wet and deteriorating in flavor even after being stored for a long period of time.

Further, the water-soluble compound derived from chitin, when added to foods, not only harms the health, but also has an excellent antibacterial action against food poisoning pathogenic bacteria and is stored for a long time. Is the best one.
Furthermore, it is also added to other foods, such as caries,
Since it is actively ingested for the purpose of preventing periodontal disease, etc., or for beauty reasons, if the above-mentioned effects are given, it is routinely taken. Since it can be ingested, it is more effective than other foods.

[0010]

EXAMPLES Examples of the present invention and experimental results will be described below.

The present invention uses a water-soluble compound derived from chitin, in which chitin is deacetylated with caustic soda and deacetylated chitin (hereinafter referred to as chitosan) is used as an organic acid. There is something dissolved in. Since chitosan is insoluble in water by itself, once it is dissolved in an organic acid, it becomes a water-soluble compound. Therefore, in the present invention, it is optimal to dissolve chitosan in an organic acid that is relatively inexpensive and has little irritation as a food. Therefore, acetic acid is used in this example.

Next, a method for producing tea leaves sprayed with an aqueous chitosan solution will be described.

As is well known, tea leaves are steamed from collected fresh leaves at 100 ° C. for 5 to 10 minutes, and after cooling,
It is thoroughly kneaded, dried and then cut. Therefore, in the middle of such a series of manufacturing steps, if the chitosan aqueous solution is sprayed, at the time of cooling after steaming, or
Optimal during the rubbing process. This is because the chitosan aqueous solution naturally contains water in that state, and if the dried tea leaves are sprayed with the chitosan aqueous solution, they must be dried again. Moreover, before the rubbing step is completed, the aqueous solution of chitosan permeates into the whole by the subsequent rubbing step, so that chitosan can be more effectively applied to the tea leaves.

When the chitosan aqueous solution is sprayed on tea leaves that have been dried up to the time immediately before bagging, or tea leaves that have already been marketed, such tea leaves are chitosan. The same state as described above can be obtained by spraying the aqueous solution, thoroughly kneading and then drying. After spraying the chitosan aqueous solution, if the chitosan aqueous solution penetrates into the entire tea leaves without rubbing, it may be used.

Since the chitosan aqueous solution can be atomized relatively easily, it can be sprayed reasonably and easily. However, before the drying step, the leaves are open, It is also possible to apply.

Next, the contents of the experiment and the results thereof will be described.

As the chitosan aqueous solution used here, a chitosan aqueous solution was prepared by dissolving chitosan in a fixed amount of acetic acid to prepare a stock solution, and adding water to the stock solution. The concentration of the chitosan aqueous solution was calculated with the above stock solution as 100%.
Further, the chitosan used in the test is one of the three types manufactured by Kimitsu Chemical Co., Ltd. as shown in Table 1 below.

[0018]

[Table 1]

1. Moisture Absorption Test The moisture absorption test was carried out by placing 25 g of each tea leaf in a petri dish and leaving it without a lid. The place to be left was carried out under two kinds of conditions, that is, a normal living room and a laboratory room where temperature and humidity were kept constant. Chitosan aqueous solution sprayed and not sprayed, chitosan aqueous solution sprayed chitosan aqueous solution concentration of 0.5% to 5.0 so that the difference in the concentration of the sprayed chitosan aqueous solution can be compared. What was sprayed up to 4% was observed at the same time in four steps. In addition, in order to remove the water contained in this aqueous solution, the one sprayed with the chitosan aqueous solution was dried at 80 degrees Celsius for about 30 minutes to remove the water contained in this aqueous solution, and the tea leaves contained on the first day of the test. Taking the amount of water remaining as 100, the increase in the amount of water over the number of days was calculated. In addition, the chitosan to be sprayed is LL in Table 1.
WP (Deacetylation degree 75-85%, viscosity 5-20c
p) was used. The experiment period was 30 days from June 20, 1993 to July 20, 1993, and the daytime temperature during this period was 23 degrees Celsius to 28 degrees Celsius, and
Humidity during the day was 72% to 85%.

The results of the test in the living room are shown in Table 2.

[0021]

[Table 2]

The results of the test under the conditions of constant temperature and humidity are shown in Table 3.

[0023]

[Table 3]

As shown in the above test results, the hygroscopicity of tea leaves decreased as the concentration of the chitosan aqueous solution increased. That is, it can be known that the dry state can be maintained for a long period of time by spraying the chitosan aqueous solution. Particularly noteworthy is that if a chitosan aqueous solution having a concentration of 1.0% or more is sprayed, the moisture absorption after 30 days is less than that after 10 days of non-sprayed tea leaves. That is, it can be said that about three times or more can be stored when observed for several days.

Next, since a chitosan aqueous solution can have a difference in viscosity, in order to investigate the relationship between this viscosity and moisture absorption, three types of chitosan aqueous solutions having the same deacetylation degree as shown in Table 1 above are used. The test was conducted in the same manner as the above test. Tea leaves have a room temperature of 30 degrees Celsius and a humidity of 90%.
It was carried out only in an environment in which the above condition was kept constant. Table 4 shows the results
It is as follows.

[0026]

[Table 4]

As can be seen from the above results, the higher the viscosity, the lower the moisture absorption. However, during the test,
It has been found that those having a viscosity of more than 20 cp are hard to become an aqueous solution. Moreover, although the high viscosity lowers the moisture absorption, the difference is small, and chitosan having a viscosity of 5 to 20 cp is most suitable for spraying tea.

2. Decomposition test of vitamins It is known that tea extract is rich in catechins and vitamins. Therefore, since it is not preferable that these decompose during storage of tea leaves, it was decided to test the degree of decomposition. In determining the degree of decomposition by the test, only the most easily decomposed vitamin C was inspected. In the test, 50 g of green tea was placed in a vinyl bag, hermetically sealed, and left indoors. At this time, the temperature was 23 to 32 degrees Celsius and the humidity was 72 to 93%.
Moreover, the chitosan aqueous solution to be sprayed has a deacetylation degree of 75.
Only a solution of ˜85% chitosan in 2.5% aqueous solution was used, and the method for quantifying vitamin C was according to the Japanese Pharmacopoeia.

The results of the test are shown in Table 5.

[0030]

[Table 5]

As shown in the above results, the residual ratio of vitamin C exceeds 90% even after 45 days, and the components contained in tea do not change due to long-term storage. I can understand that.

3. Antibacterial activity test As described above, the tea extract contains catechin, and it is known that this catechin has an antibacterial action. Therefore, by spraying a chitosan aqueous solution,
Reducing this antibacterial effect is not good when storing tea leaves, and conversely, if the antibacterial effect can be increased by spraying an aqueous solution of chitosan, the above results should be included. It can be said that it is in an optimal state. In the test, green tea leaves that were sprayed with a 2.5% aqueous solution of chitosan and then dried for about 30 minutes, and green tea leaves that had not been prepared were prepared. Warm water at 50 degrees Celsius 10
The extract is collected by immersing in 0 ml for 30 minutes and then filtering. Bacillus subtilis (Bacillus subtilu) previously cultivated at 30 degrees Celsius for 2 days was added to this extract.
s) and Staphylococcus aureus
aureus) 5 ml of the bacterial cell culture solution is dispensed and left at 30 ° C. for 24 hours to prepare a test solution. Further, 1 ml of the test solution was injected into a test tube containing 10 ml of Bouillon culture solution, and the degree of growth thereafter was visually observed. The criterion for this was the degree of turbidity of the solution in the test tube. The test results are shown in Table 6, but no difference appeared between the sprayed chitosan aqueous solution and the non-sprayed chitosan aqueous solution with the above-mentioned extract alone. A test similar to that of the extract was carried out using the diluted ones.

[0033]

[Table 6]

From the above results, it can be understood that the tea leaf extract sprayed with the chitosan aqueous solution has excellent antibacterial activity. Therefore, it can be said that the tea leaves sprayed with the chitosan aqueous solution are suitable for long-term storage.

4. Sensory test As a final test, a sensory test for flavor was performed. In the test, 10 g of tea leaf was first dipped in 400 ml of hot water to collect the extract, which eight people drank and evaluated by a three-level scale for aroma, bitterness and astringency. The result was The chitosan aqueous solution to be sprayed was 2.5%, and the tea leaves were stored in a vinyl bag, sealed and left indoors.

The results are shown in Table 7.

[0037]

[Table 7]

As shown in the above results, tea which has a slight astringency on the first day of storage and which is not sprayed with the chitosan aqueous solution is superior, but after 15 days, tea which is sprayed with chitosan due to its aroma and bitterness is better. Are better. Here, it seems that chitosan itself has astringency, which can be said to be reflected in the above results. However,
Originally, tea (particularly green tea) has some astringency, and the astringency of the above results is a little bit astringent. When drinking tea, such astringency may not be very noticeable.

As described above, the tea leaves sprayed with the chitosan aqueous solution have some astringency, but are superior to the ordinary tea leaves in terms of moisture absorption, degree of decomposition of vitamins, and antibacterial activity. This makes it possible to store tea leaves for a long period of time. In the above description, only tea leaves are described, but this tea leaf is not limited to include green tea leaves, but is not limited to green tea, and various types of tea such as black tea, Tochu tea, or oolong tea are also included. It is clear from the gist of the present invention that the same effect can be obtained by the action of chitosan even if it contains tea leaves, and that the above various tea leaves are mixed.

Claims (2)

(57) [Claims] 1. A tea leaf characterized by being attached to the surface by spraying or applying a water-soluble compound derived from chitin. 2. The tea leaf according to claim 1, wherein the water-soluble compound derived from chitin is dealkylated chitin.