parboiled polished grains. This reduction in the concentration of polyphenols
after cooking is related to the thermal decomposition, because
phenolic compounds are affected by high temperatures
(Larrauri et al., 1997; Piga et al., 2003), as previously discussed. The
reduction in polyphenol concentration after cooking was not as
great in the parboiled grains as in the brown and polished grains because
those grains had already been through a hydrothermal process
(parboiling) before cooking with the loss of part of the phenolic compounds.
The effect of cooking was also reported by Pérez-Jiménez and
Saura-Calixto (2005). Evaluating a single sample of rice, they observed
a reduction of 84.16% in the total phenolic content after
cooking.