There is enough evidence
(p < 0.05) that the beans with shell have greater concentrations
of water and VFA than the beans without shell, which is expected
because shell is in contact with the mucilage where the main fermentation
changes occurs. The drying kinetics for water and VFAs
are plotted in Fig. 4–8. It can be observed that the kinetic of water,
acetic, propionic and butyric acids represented in a semi-log scale
show an approximate linear trend one hour after of the drying
beginning. Iso-butyric acid kinetic has the greatest dispersion
probably because that this component concentration in beans
was at the limits of detection.The linear behavior was confirmed by fitting the experimental
drying kinetics, at t > 1 h, to a linear model in semi-log scale,
which results in the continuous lines plotted in Figs. 4–8.
The slopes of these lines ðm) and their 95% interval confidence limits
(calculated with Eq. (17)) were applied in Eq. (15) jointly with their
characteristic length ðl ¼ lz) listed in Table 1, for the calculation of
average diffusivities, and their confidence interval. The whole set
of the results are listed in Table 3.