Changes in Morphological and Functional Characteristics of Tea Leaves During Japanese Green Tea (Sencha) Manufacturing Process
Changes in Morphological and Functional Characteristics of Tea Leaves During Japanese Green Tea (Sencha) Manufacturing Process
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DOI：
10.1007/s11947-021-02735-7
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发表时间：
2021-11-24
影响因子：
5.6
通讯作者：
Ogawa, Yukiharu
中科院分区：
文献类型：
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作者：
Qin, Wei;Yamada, Ryutaro;Ogawa, Yukiharu
日本绿茶（煎茶）主要由蒸、初滚、滚、二次滚、末滚、末晒六个加工步骤制成。观察茶叶的形态和微观结构，评价茶叶和冲剂在加工过程中的总多酚含量（TPC）和FRAP和DPPH指标的总抗氧化活性。在加工过程中，茶叶表面褶皱或褶皱状微结构增加，特别是在初级轧制（PR）阶段。叶片形态在PR阶段也以塌陷为主。茶叶中TPC、DPPH和FRAP在处理过程中分别为189 ~ 283 mg GAE/g DM、2670 ~ 4363 μ mol FeSO4/g DM和1519 ~ 2327 μ mol TE/g DM，而热水浸提过程中则分别为14 ~ 135 mg GAE/g、391 ~ 2961 μ mol FeSO4/g DM和219 ~ 1049 μ mol TE/g DM。这些功能属性主要从蒸（ST）到滚（RL）阶段增加。结果表明，各工序的工艺条件，特别是ST、PR和RL工序的工艺条件，影响了最终茶叶产品的表观质量以及茶叶和冲剂的功能特性。
Japanese green tea (Sencha) is mainly manufactured by six processing steps: steaming, primary rolling, rolling, secondary rolling, final rolling, and final drying. The morphology and microstructure of tea leaves were observed, and total polyphenol content (TPC) and total antioxidant activity indexed by FRAP and DPPH were evaluated in tea leaves and infusions during processing. Folds or wrinkle-like microstructures on the tea leaf surface increased during processing, particularly during the primary rolling (PR) step. Leaf shape also mainly collapsed during the PR step. In tea leaves, the values of TPC, DPPH, and FRAP during processing ranged from 189 to 283 mg GAE/g dry matter (DM), 2670-4363 mu mol FeSO4/g DM, and 1519-2327 mu mol TE/g DM, respectively, whereas in the hot water extraction as a tea infusion decreased and ranged from 14 to 135 mg GAE/g, 391-2961 mu mol FeSO4/g DM, and 219-1049 mu mol TE/g DM, respectively. These functional attributes increased mainly from steaming (ST) to rolling (RL) steps. The results indicated that the processing conditions at each step, especially at the steps for ST, PR, and RL, influenced the apparent quality of the final tea leaf products and the functional properties of tea leaves and infusions.