Value-added processing with respect

Value-added processing with respect to rice milling has traditionally treated the rice bran layer as
a homogenous material that contains significant concentrations of high-value components of
interest for pharmaceutical and nutraceutical applications. Investigators have shown that high-value
components in the rice bran layer vary from differences in kernel-thickness, bran fraction, rice
variety, and environmental conditions during the growing season. The objectives of this study were
to quantify the amount of rice bran removed at pre-selected milling times and to correlate the
amount of rice bran removed at each milling time with the concentration of vitamin E, gammaoryzanol,
rice bran saccharide, and protein obtained. The ultimate goal of this research is to show
that rice bran fractionation is a useful method to obtain targeted, nutrient-rich bran samples for
value-added processing. Two long grain rice cultivars, Cheniere and Cypress, were milled at
discrete times between 3 and 40 seconds using a McGill mill to obtain bran samples for analysis.
Results showed that the highest oryzanol and protein concentrations were found in the outer
portion of the rice bran layer, while the highest rice bran saccharide concentration was found in
the inner portion of the bran layer. Vitamin E concentration showed no significant difference across
the bran layer within a variety, though the highest magnitude of concentration occurs within the
first 10 seconds of milling for both varieties. To extract the higher concentration of oryzanol and
protein only the outer portion of the bran layer requires processing, while to extract the higher
concentration of rice bran saccharide, only the inner portion of the bran layer requires processing.
Rice bran fractionation allows for the selective use of portions of the bran layer and is advantageous
for two reasons: (1) bran fractions contain higher concentrations of components of interest with
respect to the overall bran layer average, and (2) less bran needs to be processed to obtain
components of interest.