The impact of degree of milling on the contents of rice bran lipids and gamma-tocotrienol
The purpose of this research was to study the impact of milling on total lipids and γ-tocotrienol concentrations in rice brans of Cheniere and Francis varieties. The brown rice obtained after dehulling was milled to 4%, 6%, 8% and 9% milling degrees. Total lipids were analyzed using AACC method and γ-tocotrienol was quantified by reverse phase HPLC. The results indicated that Cheniere had significantly higher contents of lipids and γ-tocotrienol than Francis at all degrees of milling (p≤0.05). It was also found that lipids and γ-tocotrienol content decreased with increasing milling degree from 4% to 9%. The lipid content of the bran at 4% milling was significantly higher than the bran at 9% milling. The lowest γ-tocotrienol content was found to be 344 μg/g bran in Cheniere and 331.1 μg/g bran in Francis. Thus, γ-tocotrienol rich bran could possibly be obtained by avoiding hard milling or 9% milling degree of brown rice.