In contrast, when the parboiled polished grains were compared to
the polished grains, no significant difference was observed in the concentration
of TSPCs for most of the genotypes (Table 2). Most of the
polyphenols (62% to 97%) in the rice grains are in the external layers
of the grain that are removed during polishing, with a small concentration
of these compounds left in the polished grains, potentially
explaining the similar results. However, the exception was the genotype
with a black pericarp color (IAC 600), which presented a concentration
of phenolic compounds significantly higher in the parboiled
polished grains compared to the polished grains. This result, which
differs from the other genotypes, was obtained because during the
polishing of the parboiled grains with black pericarp color, it was
not possible to completely remove the external layer of the grain containing
the polyphenols. A light purple color remained in the grains
indicating the presence of polyphenols in the parboiled polished
grains.