Changes in Matcha Quality and Growth Characteristics from Cultivation under Different Shading

The term matcha means that tea leaves cultivated under shade are prepared by pulverizing the leaves with a grinding machine (such as a stone mill or a ball mill), turning the tea leaves into a fine powder. There is a great difference in quality depending on cultivation techniques such as the shading period and the type of shade. This study investigates the effect on growth and physiological changes of tea leaves for the production of high-quality green tea depending on the use of sequential double shading (SD-SD) and sequential single shading (S-SD). Leaf area, moisture content, photosynthetic capacity, and G-value increase based on the amount of shade in the following order: SD-SD > S-SD > no shade. Total phenolic compound and catechin content were highest in unshaded matcha. Antioxidant activity was highest in unshaded matcha, which also coincides with the highest phenolic compound content, such as catechins. Sugar content was highest from no shade, with leaves absorbing the most light energy, and the free amino acid content was highest under SD-SD. The results of taste analysis through an electronic tongue showed the highest sour taste and umami from S-SD, a salty taste from no shade, and sweet taste, bitter taste, astringent taste, and spicy taste from SD-SD. The overall physiological and growth status and beneficial ingredients showed that SD-SD increases the color of the tea leaves more than S-SD, and sequential double shading is effective in reducing stress on tea plants.