A novel single-step low-volume solvent extraction method for quantification of bioactive compounds in different rice bran varieties

AbstractA novel single-step low-volume solvent extraction (SLSE) method was developed to quantify γ-oryzanol and ferulic acid in rice bran, reducing solvent consumption and processing time compared with conventional multi-step methods. Once the adsorption coefficients (K_d) were determined, rapid and accurate quantification and prediction of extractability were enabled. At 30 °C, the K_d values obtained with methanol were 2.34 for ferulic acid and 1.41 for γ-oryzanol in rice bran, and 2.26 and 1.66 in defatted rice bran. The SLSE method showed good agreement with the partial extraction method, with maximum deviations of 5.09% for ferulic acid and 5.65% for γ-oryzanol (p > 0.05). Based on the K_d values, 90.0–90.4% of ferulic acid and 84.9–86.9% of γ-oryzanol were extracted at a solvent-to-bran ratio of 4:1, while 94.8–94.9% of ferulic acid and 91.9–93.0% of γ-oryzanol were extracted at 8:1, consistent with the experimental results. The proposed method provides a convenient, economical, and environmentally friendly approach for routine analysis, with potential application to other plant-derived compounds.