Abstract: Taking the physicochemical characteristics as indicators, the tea was superfine grinding by a production type ball mill to obtain Matcha with medium particle size of 117.094, 60.176, 40.041, 30.646, 25.282, 21.090, 19.199 and 14.209 µm, and to explore the physicochemical characteristics of Matcha at different particle sizes. The results show that with the pulverization time prolonged, the particle size of the powder gradually decreased and the degree of cell breakage increased remarkably. However, the functional group structure of the main component of the tea powder did not change. When the particle size was refined to a certain extent, the specific surface area and surface energy increased, the particles were in an unstable energy state, and prone to adhesion and agglomeration. The bulk density of the powder reduced, which was related to the increase of the porosity of the powder. Due to the increased specific surface area of the tea sample, the internal substances of the powder exposed, so that the water content and total water content reduced. The brightness of tea powder gradually increased, and the greenness increased. With the pulverization time prolonged, the content of tea polyphenols, free amino acids and other substances increased first and then decreased, while the contents of ascorbic acid and EGCG tended to reduce. The above results show that the superfine grinding process had a significant impact on the physicochemical characteristics of Matcha.

Key words: Tencha, Matcha, superfine grinding, physicochemical characteristics