A suitable Xp/Xo ratio resulted to be 0.2 and the optimal kYA and
kXA were adjusted to each kinetic data set. The values are given
in Table 4 together with the average absolute relative deviation
between calculated and experimental caffeine yield.
The optimal Xp/Xo ratio represents a Xk (amount of caffeine
inside cell walls) around 4 times higher than Xp (readily accessible
caffeine), denoting that caffeine is strongly bond in the vegetal.