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United States Department of Agriculture

Agricultural Research Service

Title: Tocopherol and Tocotrienol Content in Crude and Processed Rice Bran Oils

Authors
item Rennick, Kathy
item Abidi, Sharon

Submitted to: Pittsburgh Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 22, 2002
Publication Date: October 20, 2002
Citation: RENNICK, K.A., ABIDI, S.L. TOCOPHEROL AND TOCOTRIENOL CONTENT IN CRUDE AND PROCESSED RICE BRAN OILS. PITTSBURGH CONFERENCE. 2002. Abstracts p. 1574.

Technical Abstract: Tocol(vitamin E) is a fat-soluble vitamin naturally occurring in grains, vegetable seeds and oils. This complex includes the compounds: tocopherol(T), containing a saturated side chain and tocotrienol(T3), containing an unsaturated side chain. Tocols have gained importance due to their antioxidative properties(T) and cholesterol lowering(T3) health benefits. Therefore, chromatographic resolution and quantitation of tocols from natural sources has gained interest. Common sources include corn, wheat, soy and peanut(higher in T), and, palm, rice bran, oat, coconut, and barley(higher in T3). Rice bran, a by-product of rice milling, is reported to be 18-22% oil content. This makes it one of the richest oil sources from grain products. Normal(NP) and reversed- phase(RP) high-performance liquid chromatography separations(HPLC) of tocols, although well established, have unique problems. While RP has greater reproducibility of retention times, quicker equilibration, and higher column stability than NP, RPHPLC with an octadecysilica column cannot resolve the beta and gamma isomers. However, RPHPLC with a modified phenyl phase column results in the separation of these isomeric compounds. The mobile phase consists of methanol/water(90:10), with a flow rate of 0.5ml/min. Separation of standard T and T3 was achieved with fluorescence detection. The order of separation is T3(delta>beta>gamma>alpha)>T(delta>beta>gamma>alpha). The evaluation of T and T3 content in eight(8) crude and refined, bleached, and deodorized(RBD) rice bran oil samples is presented. The major compounds in all samples were gammaT3(~50%) and alphaT(~20%). The processing of the crude to RBD oil results in the loss of T and T3 by 30-50%.

Last Modified: 11/22/2014
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