Similar to other cereal grains, the phenolic compounds in rice exist
in the soluble and insoluble (bound) form, with the soluble form
representing 38% (Adom & Liu, 2002) to 60% (Mira, de Massaretto,
Pascual, & Lanfer-Marquez, 2009) of the total polyphenols content
in light brown rice grains, and around 81% in red and black pericarp
color grains (Mira et al., 2009).