Brewing times
The effect of brewing time (1, 3, 5, 10, 15 and 20 min) upon TPC
and FRAP was further investigated using water at a temperature
of 100 ◦C (Fig. 3). The TPC and FRAP values of C. asiatica herbal
teas showed no specific trend after a brewing time of 10 min. The
TPC of CAFF increased continuously with infusion time, while the
CANF values increased continuously until a time of 15 min and
then decreased at 20 min. A similar trend was also observed in the
FRAP values of C. asiatica herbal teas after 10 min of infusion time.
Both the TPC and FRAP values increased rapidly with brewing
time and generally reached a constant value at a brewing time of
10 min, with prolonged extractions having no significant effect on
these values.