3.2.2. Effect of extraction time
Fig. 3 shows the effect of extraction time on the yield at 50 and
70 C.
An increasing trend of extract yield with time was observed
from 0.25 to 2 h. This is expected given that sufficient extraction
time is needed for the liquid to penetrate into the plant material
and dissolve the active components, and for the dissolved active
components diffuse out from the plant materials (Samavati, 2013;
Ye and Jiang, 2011). The maximum yield was observed at 2 h, and
decreased from 2 to 5 h. This supports the observations and hypothesis
derived from Fig. 1, whereby prolonged exposure at high
temperatures may cause decomposition or hydrolysis of the target
compounds and thus decrease the extract yield (Chemat and
Cravotto, 2013)