[0042] Also prepared as a comparative product was a product which was subjected only to a decompression and degasification treatment without performing any water-adding treatment (Comparative Product 1). Using a product that was not subjected to a water-adding
treatment and a decompression and degasification treatment as a control, the reduction of the กลิ่นใบที่แก่เกินไป of the การประดิษฐ์นี้ Products 1 to 3 and that of the Comparative Product was compared. Specifically, a variety of obtained tea leaves (อะราชะ) were
measured off at 2.0 g each, extracted for 5 mins. with 200 g of hot water to obtain tea leaf
extracts, and the extracts were subjected to sensory tests based on the following standard. ++++ : กลิ่นใบที่แก่เกินไป is felt very strongly.
+++ : กลิ่นใบที่แก่เกินไป is felt strongly. ++ : กลิ่นใบที่แก่เกินไป is felt.
+ : กลิ่นใบที่แก่เกินไป is felt weakly.
- : No กลิ่นใบที่แก่เกินไป is felt.
[0043] Table 1 shows the results. A very strong กลิ่นใบที่แก่เกินไป was felt for the อะราชะ that has not been subjected to the water-adding treatment and the drying treatment (control). Also, when subjected only to the drying treatment without performing the water-
adding treatment, no change occurred in the กลิ่นใบที่แก่เกินไป even after 120 mins of the drying treatment at a decompressed pressure of 20 hPa or lower (Comparative Example
1). On the other hand, the กลิ่นใบที่แก่เกินไป of the อะราชะ that was subjected to a
water-adding treatment and a drying treatment (การประดิษฐ์นี้ Products 1 to 3) was
reduced largely compared to the control. This result suggests that subjecting tea leaves with an กลิ่นใบที่แก่เกินไป to a water-adding treatment, and subsequently to a drying
treatment until the added moisture is dried, would effectively and efficiently remove the กลิ่นใบที่แก่เกินไป. Note that the กลิ่นใบที่แก่เกินไป level of "++" is the desirable level of quality.
[0044] [Table 1]
Control
Tea leaf amt. g 100
Added water amt. g 0 performance of
decompression and No degasification
hot water bath temp. °C -
level of over matured leaf ++++
smell
[0045]
Tea leaves were produced by using the same tea leaves as Example 1 in an amount of 100 g as the subject tea leaves, and the drying treatment device was changed to a drum-
type drier (compact roasting device "Meika" manufactured by Terada Seisakusho., Ltd.) with the fan set to rotate at 20 rpm. Specifically, the following products were produced: tea leaf product produced by adding 20 g of water (ion exchange water) a little at a time using a
commercially available atomizer while mixing the tea leaves similarly to Example 1, then putting them into a drum-type drier (surface temperature of the kiln: 120°C) to be subjected to a drying treatment until the moisture content of the tea leaves reach about 4 to 5% (การประดิษฐ์นี้ Product 4); a tea leaf product produced by using a dropper instead of an atomizer and dripping 20 g of water to the subject tea leaves at a stationary state, then putting the tea leaves into the drum-type drier (surface temperature of the kiln: 120°C) after letting the tea leaves sufficiently absorb moisture to subject the tea leaves to a drying treatment until the moisture content of the tea leaves reaches about 4 to 5% (การประดิษฐ์นี้ Product 5); a tea leaf product produced by first putting the subject tea leaves into the drum-type drier (surface temperature of the kiln: 120°C) and immediately dropping 20 g of water with a dropper, then subjecting them to a drying treatment until the moisture content of the tea leaves reach about
4 to 5% (การประดิษฐ์นี้ Product 6). In addition, tea leaves similar to การประดิษฐ์นี้ Product 6 except that the water to be dropped, divided to 10 g + 5 g + 5 g, were added at three separate timings (the second addition and after were performed at the time the tea leaf temperature rose to about 65°C) (การประดิษฐ์นี้ Product 7). In all cases, the drying treatment was terminated when the tea leaf temperature reached 75°C, afterwhich the tea leaves were taken out of the drum. The obtained tea leaves (control and การประดิษฐ์นี้ Products 4 to 7) were subjected to a sensory test concerning the level of กลิ่นใบที่แก่เกินไป similar to Example 1.
[0046] Table 2 shows the results. The กลิ่นใบที่แก่เกินไป of the การประดิษฐ์นี้ products subjected to water-adding treatment and drying treatment is reduced compared to อะราชะ that was subjected to neither a water-adding treatment nor a drying treatment
(control). The reduction of กลิ่นใบที่แก่เกินไป was small in tea leaves that did not have moisture uniformly attached over their entirety (การประดิษฐ์นี้ Product 5). Also, the reduction of กลิ่นใบที่แก่เกินไป was small tea leaves for which water-adding was
-16-
performed only once (การประดิษฐ์นี้ Product 6). On the other hand, when water was
added in portions to the subject tea leaves rotating (mixed) in the heated drum-type drier,
there was an effective reduction of the กลิ่นใบที่แก่เกินไป (การประดิษฐ์นี้ Product 7). The result suggests that it is preferable to add moisture under mixing so that moisture will attach uniformly to the subject tea leaves, and it is preferable to repeat the water-adding
treatment and the drying treatment.