Quality constituents of high amino acid content tea cultivars with various leaf colors

Abstract

Green tea made from high amino acid content (HAAC) tea cultivars with different leaf colors exhibits many similarcharacteristics, such as slight bitterness, a rich aroma, and a refreshing and velvety taste. To determine differences in the key constituentsof five HAAC tea cultivars with various leaf colors, the cultivars quality constituents were systematically analyzed and compared with thatof a normal green tea cultivar. High theanine (Thea) content and the synthesis of Thea precursors are extremely important determinantsof the character of these HAAC tea cultivars. The levels of most catechins, carotenoids, and chlorophylls in the HAAC tea cultivarswere significantly lower than those in the normal tea cultivar, as was that of caffeine. The present study suggests that the inhibitionof catechins (particularly epicatechins; ECs), chlorophylls, carotenoids, and caffeine biosyntheses in HAAC tea cultivars directs themetabolic network toward amino acid biosynthesis, particularly Thea biosynthesis.