Binary Solvent Extraction of Tocols, γ-Oryzanol, and Ferulic Acid from Rice Bran Using Alkaline Treatment Combined with Ultrasonication

Alkaline treatment (Alk) combined with ultrasound-assisted extraction (UAE) (Alk+UAE) was examined as a means of extracting tocols and gamma-oryzanol from rice bran into an organic phase while simultaneously recovering ferulic acid into an aqueous phase:The tocols and gamma-oryzanol/ferulic acid yields were determined using high-performance liquid chromatography with fluorescence and UV detection. The effects of extraction conditions were evaluated by varying the Alk treatment temperature and extraction duration. The maximum yields of tocols and gamma-oryzanol were obtained at 25 degrees C over a time span of 30 min. When the temperature was increased to 80 degrees C, the yield of ferulic acid increased dramatically, whereas the recovery of gamma-oryzanol slightly decreased. Employing the Alk+UAE procedure, the recovered concentrations of tocols, gamma-oryzanol, and ferulic acid were in the ranges of 146-518, 1591-3629, and 352-970 mu g/g, respectively. These results are in good agreement with those reported for rice bran samples from Thailand.