The statistical results of PLS calibration models for the determination
of TPC, CV, CD and CT using transmission FTIR spectroscopy
are shown in Table 1. The analytical performance of FTIR method
with reference to reported method was found to be outstanding.
The number of factors used in the PLS calibration models were
automatically selected by the TQ analyst software to obtain the
lowest predicted residual error sum of square (PRESS) values. For
each PLS models relative to individual sample 11 calibration points
(o) and 2 validation points (+) were used to check the accuracy. The
low value of RMSECV for TPC, CV, CD and CT demonstrated the
suitability of the proposed method. FT-IR spectral pre-treatment
and data correction was carried out as per reported procedure
[44]. The predictability of the models was tested by computing
RMSEP according to reported studies [45,46].