ADVANTAGEOUS EFFECTS OF INVENTION
[0011] The การประดิษฐ์นี้ enables reduction of กลิ่นใบที่แก่เกินไป in tea leaves of green tea and reduction of กลิ่นใบที่แก่เกินไป in refined tea or green tea beverage.
BRIEF DESCRIPTION OF DRAWINGS
[0012] The การประดิษฐ์นี้ relates to a production method of tea leaves having reduced
กลิ่นใบที่แก่เกินไป. The production method of the การประดิษฐ์นี้ is based on a
finding that the กลิ่นใบที่แก่เกินไป, which is an aroma component belonging to the water soluble fraction, may be efficiently reduced by adding water to อะราชะ and/or refined tea and drying the same until the moisture approximates to that before adding water. The common idea behind green tea beverages is that aroma is an important factor of quality, and as much aroma as possible should be allowed to seep out from tea leaves into water for people to
enjoy. Under such circumstances, a person skilled in the art would commonly not think of adding water to the tea leaves to reduce or remove the water soluble fraction.
[0013] The "กลิ่นใบที่แก่เกินไป" in the present specification is a type of aroma of
green tea, particularly an aroma existing in a majority of low class goods below a certain
standard, which is a greenish, unpleasant smell that stands out. Also, "อะราชะ" in the
การประดิษฐ์นี้ is a product processed from tea obtained by subjecting fresh leaves plucked from a tea plant (nomenclature: Camellia sinensis) to the tea manufacturing step, and the "refined tea" is tea leaves obtained by subjecting อะราชะ to the refining process step, such as roasting or selection.
[0014] The embodiment of the การประดิษฐ์นี้ is described in more detail below. [0015]
The production process of the การประดิษฐ์นี้ includes a step of adding an
appropriate amount of moisture to tea leaves having an กลิ่นใบที่แก่เกินไป (hereinafter referred to as "the subject tea leaves") (water-adding treatment) and a step of drying and
removing the added moisture (drying treatment). The กลิ่นใบที่แก่เกินไป would not change at all just by applying conventionally known aroma component separation and
removal technology (e.g. decompression by an evaporator) to the subject tea leaves, and such technology cannot reduce the กลิ่นใบที่แก่เกินไป in the subject tea leaves. However, through an incorporation of an appropriate amount of water in the subject tea leaves having an กลิ่นใบที่แก่เกินไป, the การประดิษฐ์นี้ can easily separate and remove the กลิ่นใบที่แก่เกินไป by using the affinity between a causative component of the กลิ่นใบที่แก่เกินไป (may be referred to hereinafter as the กลิ่นใบที่แก่เกินไป component) and
water (refer to the Examples provided below).
[0016] The water to be added in the การประดิษฐ์นี้ is a simple tap water, deionized water, distilled water, natural water, etc., and it does not contain components other than water, such as amino acid or tea leaf extract. The การประดิษฐ์นี้ is expected to remove the over
matured leaf smell component, which is in a water soluble fraction, along with the water loss in the drying treatment. The presence of components other than water may bring about
unexpected reactions, such as a change in the affinity of the กลิ่นใบที่แก่เกินไป to water, or a change in the preferred aroma balance of the tea leaves. As long as the effect of the การประดิษฐ์นี้ is not lost, it is possible to appropriately add sugar, emulsifiers, acids such as hydrochloric acid or acetic acid, alkalis such as baking soda, anti oxidants such as ascorbic acid, or liquids that are easily mixed with water (e.g. acetic acid, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, glycerin, etc).
[0017] When the temperature of the added water is too high, it facilitates elution of soluble components in the tea leaves, and it facilitates scattering of preferred aroma components of tea leaves other than the กลิ่นใบที่แก่เกินไป component, so the water added in the water-
adding treatment should be 40°C or lower, ที่ควรใช้คือ 30°C or lower.
[0018] The การประดิษฐ์นี้ removes the over matured tea leaf component that is a water soluble fraction by adding water to tea leaves then drying that water, and water needs to be added in an amount that can sufficiently moisturize the entire tea leaves. Hence, the amount of water to be added is appropriate at 5 to 120 wt%, ที่ควรใช้คือ about 10 to 110 wt%, and
ที่ควรใช้กว่าคือ 20 to 100 wt% against the subject tea leaves. When the addition of water is in an amount smaller than 5 wt% against the subject tea leaves, removal of the กลิ่นใบที่แก่เกินไป component may not be effectively removed. When the addition of water is in an amount greater than 120 wt% against the subject tea leaves, the desired tea leaf flavor may not be obtained since the soluble component in the subject tea leaves may solve out to water or flavor loss may occur.
[0019] The method of adding water is not particularly limited, but possible options include methods of dropping water on to the subject leaves by using spraying or sprinkling means,
such as a spray, a funnel or a dropper, while mixing and absorbing water in the process.
Various mixing devices such as a container rotation mixer, a stirring mixer and a drum mixer may be used as means for mixing the subject tea leaves and added water.
[0020] When the amount of water to be added at once during the water-adding treatment of the การประดิษฐ์นี้ is large, the soluble component in the subject tea leaves may
undesirably solve out into water. It may also lead to the added water attaching to the drum wall to decrease the temperature of the drum instead of playing the expected role of attaching to the tea leaves and removing the กลิ่นใบที่แก่เกินไป as it evaporates. There are also possibilities of the water concentrating in one section and providing an uneven quality, the added water causing a decrease in the yield or a bum by attaching to the wall of the device as the leaves dry, the subject tea leaves sticking to each other and their surfaces drying up so that moisture is trapped inside, which results in decay, and the like. The appropriate amount of water to be added at once is about 5 to 20 wt against the subject tea leaves, and a more preferable amount of water to be added at once is about 5 to 15 wt% against the subject tea leaves. In other words, water of 5 to 20 wt% (ที่ควรใช้คือ 5 to 15 wt%) against the subject tea leaves should ที่ควรใช้คือ be added in stages divided into multiple timings to achieve a total amount of water added of about 10 to 120 wt% against the subject tea leaves, and
ที่ควรใช้คือ the step of adding water and mixing should be repeated or water should be added under mixing so that the entire subject tea leaves are moisturized uniformly.
[0021] The การประดิษฐ์นี้ ประกอบรวมด้วย removing moisture added to the subject tea leaves by the drying treatment to separate and remove the กลิ่นใบที่แก่เกินไป along with the moisture. The กลิ่นใบที่แก่เกินไป can be effectively reduced and removed by
performing the drying treatment under a mild, low temperature condition, and not a high
temperature condition such as roasting (firing). A given refining process may be performed after the treatments of the การประดิษฐ์นี้ with a given roasting intensity.
[0022] The drying treatment device may be any of decompression drying device, freeze drying device, drum-type food drying device, etc. It is particularly preferable to use the drum-type food drying device, since the water-added subject tea leaves are likely to contact
hot air in the rotation, and the entire tea leaves would be dried uniformly in a relatively short time. A commercialized drum type roasting device equipped with a nozzle to sprinkle or spray a predetermined amount of water may be used in place of the drying treatment device of the การประดิษฐ์นี้.
[0023] The drying treatment is ที่ควรใช้คือ performed under a low temperature to maintain the fine aroma or color tone of the tea leaves. Specifically, a drying condition in which the temperature of the subject tea leaves is 85°C or lower, ที่ควรใช้คือ 80°C or lower is preferred. When a temperature of the tea leaves is mentioned in the present specification, it is referring to the surface temperature of the tea leaves. When using a decompression drying device such as an evaporator, for example, the temperature of the hot water bath to heat the
container containing the sample, which differs by the degree of vacuum, should be heated to about 40 to 80°C, ที่ควรใช้คือ to about 50+10°C. Care should be taken when elevating the temperature of the hot water bath, since the drying rate generally rises with the temperature of the hot water bath, but when the degree of vacuum is low at that time, the tea leaf
temperature rises and causes browning of the tea leaves or deterioration of aroma. When using a device that dries the tea leaves by heating with hot air, etc., such as the drum type drying device, the temperature in the drum or the surface temperature of the tank of the drum should be set to make the temperature of the subject tea leaves, an achieved temperature of 85°C, or ที่ควรใช้คือ 80°C.
[0024] The drying treatment in the การประดิษฐ์นี้ is performed until the moisture con