阅读说明：本技术 一种碾茶及其加工工艺 (Ground tea and processing technology thereof ) 是由 许勇泉 毛雅琳 汪芳 尹军峰 胡美娟 胡振长 许心青 来水龙 于 2019-09-26 设计创作，主要内容包括：本发明提供一种碾茶及其加工工艺。一种碾茶加工工艺,包括鲜叶蒸汽杀青和烘干的步骤,在所述鲜叶蒸汽杀青和烘干的步骤之间,还包括：将经鲜叶蒸汽杀青得到的杀青叶在容器中进行搅拌处理,所述容器的内壁为铜质材料。本发明提供的碾茶加工工艺,通过将经鲜叶蒸汽杀青得到的杀青叶在内壁为铜质材料的容器中进行搅拌处理,然后再进行烘干,保留叶绿素含量更高,加工得到的碾茶成品颜色更绿；采用本发明方法得到的碾茶加工成抹茶,在光照处理下比现有抹茶颜色稳定性更好,光照处理12小时后,色差a值和b值的变化率不高于8％。(The invention provides ground tea and a processing technology thereof. A tea grinding processing technology comprises the steps of fresh leaf steam deactivation and drying, and further comprises the following steps between the steps of fresh leaf steam deactivation and drying: and (3) carrying out stirring treatment on the de-enzymed leaves obtained by steam de-enzyming the fresh leaves in a container, wherein the inner wall of the container is made of a copper material. According to the tea grinding processing technology provided by the invention, the de-enzymed leaves obtained by steam de-enzyming of the fresh leaves are stirred in the container with the inner wall made of copper material and then dried, so that the chlorophyll content is kept higher, and the finished product of the ground tea obtained by processing is greener in color; the green tea processed by the ground tea obtained by the method has better color stability under illumination treatment than the prior green tea, and the change rate of the color difference a value and the color difference b value is not higher than 8 percent after 12 hours of illumination treatment.)

1. the tea grinding processing technology comprises the steps of fresh leaf steam deactivation and drying, and is characterized by further comprising the following steps of between the steps of fresh leaf steam deactivation and drying:

And (3) carrying out stirring treatment on the de-enzymed leaves obtained by steam de-enzyming the fresh leaves in a container, wherein the inner wall of the container is made of a copper material.

2. a process for milling tea as claimed in claim 1, wherein the temperature of the agitation treatment is 20-40 ℃.

3. The process of claim 1, wherein the stirring speed is 90-300rpm and the stirring time is 5-30 min.

4. The tea milling process according to claim 1, further comprising a step of hot air dehumidifying the blanched leaves before the stirring treatment.

5. the tea milling process according to claim 1, wherein the hot air temperature in the hot air dehumidification step is 30 to 50 ℃.

6. The tea milling process according to claim 1, further comprising:

And performing dispersed cooling treatment on the stirred enzyme-deactivated leaves.

7. The tea grinding process as claimed in claim 1, wherein in the step of steam de-enzyming, the steam pressure is 0.01-0.05MPa, the temperature is 100-130 ℃, and the de-enzyming time is 5-30S.

8. The tea grinding processing technology according to claim 1, wherein in the drying step, the tea is dried until the water content of the blanched leaves is 8% -15%.

9. the tea milling process according to claim 1, further comprising, after the drying step: separating stems and leaves for the first time, drying for the second time and separating stems and leaves for the second time.

10. Milled tea, characterized in that it is obtained by the process of any one of claims 1 to 9.

Technical Field

The invention relates to the field of tea processing, in particular to ground tea and a processing technology thereof.

Background

The matcha (ancient Chinese called powder tea) originated from the last millennium of China, and the ancient times of the tea has been the history of thousands of years, and the ancient times of the matcha is that the tender leaves of the tea in spring are made into cake tea (tea roll) after being steamed, the cake tea is stored, the cake tea is baked and dried again on fire before being eaten, and the cake tea is directly brewed and drunk after being ground into powder by natural stone. Since Ming dynasty, tea leaves are used instead, soup is brewed and drunk, and tea dregs are discarded. Nowadays, as international food production enterprises put forward food with matcha taste in China, such as matcha ice cream, matcha milk and the like, the Chinese people have higher and higher interest in matcha. Modern matcha is prepared by grinding and sieving tea leaves, and is a refined tea product. The ground tea is raw tea of matcha, actually, the ground tea is primary steamed green tea, and the quality of the ground tea directly influences the quality of the matcha.

The processing technology of the ground tea generally comprises the steps of fresh leaf steam deactivation, cooling, drying, stem and leaf separation and the like. The tea leaves drunk by a direct brewing way generally have higher requirements on shape, color and luster, and the ground tea needs to be separated from stems and leaves, does not pursue the shape, pays attention to the color and the fragrance, and particularly has better quality as the color of the ground tea is greener, so the ground tea usually adopts fresh leaves with high chlorophyll content as a raw material. Chlorophyll is a green pigment contained in higher plants and other organisms capable of photosynthesis, is a magnesium porphyrin compound, has poor stability, can be decomposed by light, acid, alkali, oxygen, an oxidizing agent and the like, and is decomposed into pheophytin which is yellowish brown so as to influence the color of the chlorophyll. In the drying step of the tea grinding processing technology, the temperature in the tea grinding furnace is high, so that chlorophyll is easily decomposed, and in addition, the ground tea needs to be refrigerated or stored in a dark place after being processed, and the chlorophyll in the ground tea is unstable, so that the color of the ground tea finished product and the color of the ground tea processed to obtain the matcha are affected.

Disclosure of Invention

therefore, the invention aims to overcome the defect that the color of a finished product of ground tea is affected because chlorophyll is unstable and easy to decompose in the ground tea processing technology in the prior art, and provides ground tea and a processing technology thereof.

A tea grinding processing technology comprises the steps of fresh leaf steam deactivation and drying, and further comprises the following steps between the steps of fresh leaf steam deactivation and drying:

And (3) carrying out stirring treatment on the de-enzymed leaves obtained by steam de-enzyming the fresh leaves in a container, wherein the inner wall of the container is made of a copper material.

Further, the temperature of the stirring treatment is 20-40 ℃.

Further, the speed of the stirring treatment is 90-300rpm, and the stirring time is 3-12 min.

further, the method also comprises the step of carrying out hot air dehumidification on the fixation leaves before the stirring treatment.

Further, in the hot air dehumidification step, the temperature of the hot air is 30-50 ℃.

further, the water content of the enzyme-removed leaves after hot air dehumidification is 62-85%.

further, the tea grinding processing technology further comprises the following steps:

And performing dispersed cooling treatment on the stirred enzyme-deactivated leaves.

further, in the step of steam de-enzyming, the steam pressure is 0.01-0.05MPa, the temperature is 100-130 ℃, and the de-enzyming time is 5-30S.

Further, in the drying step, drying is carried out until the water content of the enzyme-deactivated leaves is 8% -15%.

further, a steam de-enzyming machine is adopted to carry out the steam de-enzyming step, the steam flow is 90-150kg/h, the inclination angle of the cylinder body is 8-14 degrees, the rotation speed of the cylinder body is 25-50rpm, and the stirring speed is 250-700 rpm.

further, a tea grinding furnace is adopted for carrying out the drying step, the enzyme-removed leaves sequentially pass through a first temperature zone, a second temperature zone, a third temperature zone and a fourth temperature zone, the temperature of the first temperature zone is 130-170 ℃, and the chain speed is 60 rpm; the temperature of the second temperature zone is 70-120 ℃, and the chain speed is 30 rpm; the temperature of the third temperature zone is 80-130 ℃, and the chain speed is 40 rpm; the temperature of the fourth temperature zone is 80-130 ℃, and the chain speed is 50 rpm.

Further, the water content of the dried enzyme-removed leaves is 10% -12%.

Further, the drying step is followed by: separating stems and leaves for the first time, drying for the second time and separating stems and leaves for the second time.

Further, the first stalk and leaf separation is carried out to obtain 4-20 meshes of crude ground tea.

Further, the secondary drying is carried out by adopting a chain plate type dryer, the drying temperature is 60-100 ℃, the chain speed is 40-60rpm, and the ground tea crude product with the water content of 2-5% is obtained.

further, the processing technology of the ground tea also comprises a step of air separation.

Further, the processing technology of the ground tea also comprises a step of color selection.

Further, the fresh leaves are subjected to fresh-keeping treatment before steam deactivation.

Further, 1 bud of 4-6 leaves of fresh tea tree is picked from the tea tree which is shaded and covered for 10-24 days, and the variety of the tea tree can be selected from: North, Oregan, Longjing 43, Zhongcha 108, Zhongcha 302, Zhangfuding, JIUJIU;

Further, the fresh leaves are cut into 5-10cm fragments before steam deactivation, and the fragments are screened by a vibrating screen to remove old stems and old leaves.

The invention also provides the ground tea which is obtained by adopting the ground tea processing technology.

the technical scheme of the invention has the following advantages:

1. According to the tea grinding processing technology provided by the invention, the de-enzymed leaves obtained by steam de-enzyming of the fresh leaves are stirred in the container with the inner wall made of copper material and then dried, so that the chlorophyll content is kept higher, and the finished product of the ground tea obtained by processing is greener in color; the green tea processed by the ground tea obtained by the method has better color stability under illumination treatment than the prior green tea, and the change rate of the color difference a value and the color difference b value is lower than 10 percent after 12 hours of illumination treatment.

2. according to the tea grinding processing technology provided by the invention, the fixation leaves are subjected to hot air dehumidification before stirring treatment, so that the fixation leaves in the stirring treatment are prevented from being adhered due to high water content, and the stirring treatment effect is poor; the fixation leaves are dried by hot air dehumidification in advance, so that the later drying step is facilitated, and the yield is increased.

3. The ground tea provided by the invention has high chlorophyll content and dark green color, and the green tea obtained by processing has bright green color, good stability and difficult color change under illumination.

Detailed Description

the following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.