• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.719-722
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• 2011

The Daecha-12 and Yabukita varieties of powdered green teas were grown under 85% shade-cultivated condition, and their physicochemical properties were analyzed. Total catechin content was not significantly different but, non-gallated catechin content in Daecha-12 was significantly higher than that in Yabukita. Theanine (32%), caffeine (14%), lutein (15%) and total chlorophyll (28%) levels were significantly higher in Daecha-12 than those in Yabukita. The results of a color analysis showed that the lightness L-value of Yabukita was higher than that of Daecha-12 but, that the greenness negative a-value and b-values of Daecha-12 were higher than those of Yabukita. The Daecha-12 cultivar had lower catechin content but higher content of theanine, caffeine, theobromine, lutein, chlorophyll, and a negative a-value than those of the Yabukita cultivar. Thus, the Daecha-12 cultivar is suitable to prepare a high-quality powdered green tea product.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.21-26
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• 2010

Microbial-fermented tea (MFT), which is made by microorganisms through fermentation, is a popular beverage in Asia, especially in the Yunnam province, China. In this study, changes of the chemical constituents and antioxidant activity during the manufacturing process of MFT were investigated. MFT were respectively prepared from fresh leaves of three different tea species (Yabukita, Daecha, and Korean wild cultivar) and a processed green tea (Korean wild cultivar). The color of the tea infusions gradually changed to red and yellow as a function of fermentation time. Total nitrogen and caffeine contents were not significantly changed. Whereas, the chlorophyll, tannin, and total catechins contents gradually decreased. Interestingly, the epicatechin and epigallocatechin contents increased up to 25 days of fermentation and then decreased. Change of the chemical constituents of all samples showed the same patterns. The antioxidant activity of MFT from Daecha and Yabukita slightly decreased as increasing fermentation time. However, the range over which the antioxidant activity of MFT from Korean wild cultivar and green tea were not changed. This research suggests that it may be possible to manufacturing possibility of MFT using Korean wild cultivar and processed green tea.