Deciphering the proteome profile of rice (Oryza sativa) bran: a pilot study.

The exact knowledge of the qualitative and quantitative protein components of rice bran
is an essential aspect to be considered for a better understanding of the functional
properties of this resource. Aim of the present investigation was to extract the largest
number of rice bran proteins and to obtain their qualitative characterization. For this
purpose, three different extraction protocols have been applied either on full-fat or on
defatted rice bran. Likewise, to identify the highest number of proteins, MS data collected
from 1-DE, 2-DE and gel-free procedures have been combined. These approaches allowed
to unambiguously identify 43 proteins that were classified as signalling/regulation
proteins (30%), proteins with enzymatic activity (30%), storage proteins (30%), transfer
(5%) and structural (5%) proteins. The fact that all extraction and identification procedures
have been performed in triplicate with an excellent reproducibility provides a
rationale for considering the platform of proteins shown in this study as the potential
proteome profile of rice bran. It also represents a source of information to evaluate better
the qualities of rice bran as food resource.