γ-oryzanol, a phytochemical, has antioxidant activities and potential health benefits. In this study, we aimed to develop a method for extracting high amounts of γ-oryzanol from rice bran and for verifying its stability in different solvents. Of the 5 methods under investigation, the one that yielded the highest γ-oryzanol content was further improved by using a central composite rotational design (DCCR - 2(4), including 8 tests in axial conditions and 4 central points, totaling 28 trials). The parameters under study were temperature, time, volume, and the ratio of hexane:isopropanol. High γ-oryzanol content (13.98 mg.g-1) was obtained by using the following extraction conditions: 40° C, 40 min, and 75 mL hexane:isopropanol (1:3). The limits of detection and quantification of the method were 0.9 µg g-1 and 31 µg g-1, respectively. The instrumental precision was 0.004%, the repeatability (CVr) was 9.4%, and the recovery was 111.7 ± 17.7%. γ-oryzanol is more stable in isopropanol than in hexane, in which 100% concentration could be maintained after refrigeration for 72 days.
Antioxidant; spectrophotometer; stability; phytochemistry
