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Rice bran was extruded at 110, 120, 130, and 140℃ with post extrusion holding times of 0, 3, and 6 min to stabilize rice bran. The kinetic parameters for the degradation of tocopherols, tocotrienols, and oryzanol were determined during extrusion processing to be a first-order reaction. The degradation rate constants increased 1.3-2.1 fold with an increase in extrusion temperature from 110 to 140℃. The ranges of activation energies (E_a) of vitamin E vitamers and oryzanol were 3.1-7.3 and 7.9 ㎉/㏖, respectively. Total tocotrienols had higher a E_a value than that of total tocopherols. Oryzanol had the highest E_a value of the antioxidants. The order of E,, values of vitamin E vitamers during extrusion processing was β-T>δ-T>γ-T>α-T3>δ-T3>γ-T3>α-T. The order of degradation of vitamin E vitamers in extruded rice bran for all extrusion temperatures was γ-T3>α-T>α-T3>γ-T>α-T3>β-T>δ-T. Q_(10) values of vitamin E vitamers and oryzanol were 1.12-1.28 and 1.30, respectively.
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