To check the performance of the calibration model,
whose regression coefficient could be directly used in
prediction, 164 external validation samples were used.
The prediction results were almost of a similar nature to
the calibration results (Table 1). The calibration and
validation results show that the SEC, SEP andRvalues
are similar, with no significant bias in either case.
Similarities in these values also remove the probability
of overfitting of the model. A comparison of the scatter
plots of actual TSS valuesversus computed ones for
calibration (Fig. 2) and validation (Fig. 3) also showed
that the visual reflectance spectra and destructive
standard methods gave closer results. Malevskiet al.
(1977) also report that there is a relationship between
initial colourand TSS of mango while Medlicottet al.
(1992)said that changes in peel colouris slightly delayed
in relation to the changes in TSS of mango. Both
reported works for ripe mango only; support the result
of this paper, which includes both ripe and unripe
(freshly harvested matured as well as immature)
mangoes