Mineral Contents of Green Tea Grown at Various Places of Japan

Abstract

Content of several minerals (sodium (Na), magnesium (Mg), aluminum (Al), calcium (Ca), manganese (Mn), iron (Fe), nickel (Ni) and zinc (Zn)) in 27 samples of Japanese green tea leaves were determined by inductively coupled plasma spectrometry. The 27 samples were consisted of ones cultivated at Nan-sei islands (n = 3), Kyushu island (n = 8) , Shizuoka Prefecture (n = 10) and other places (n = 6) in Japan. Median value of the content of each mineral was as follows (mg/ 100 g dry leaf) : Na, 1.7; Mg, 141.6; Al, 33.9; Ca, 228.3; Mn, 50.2: Fe, 7.0; Ni, 0.4; Zn, 2.1. A regional variation was observed in Na, Mg, Ca and Zn contents. Infusion rates of Ca, Fe, Mn and Mg were 6.9, 10.9, 16.5, 23.9 and 33.4% respectively. These results indicate that an intake of green tea drink highly contributes the daily intakes of Mn and Al in Japanese population.