Further, from the PCA scores scatter plot involving PC1 and PC2,
it can be seen that
though one cannot discriminate between different levels of gamma
irradiation, but it is clearly possible to distinguish between irradiated
and non-irradiated soybeans. The PCA scores scatter plot using
the three first principal components also indicates be possible to
separate the irradiated and non-irradiated samples only (data not
shown). Thus, considering that the irradiated samples form a
unique cluster, we grouped them into the namely irradiated samples,
for the PLS-DA analysis.