Phytochemical characterization of defatted rice bran and optimization of a process for their extraction and enrichment

The aim of this study was to characterize the defatted rice bran (DRB) employing HPLC for identifying the major phytochemicals in DRB and to examine its commercial potential as a source of bioactive phytochemicals leading to value addition of DRB otherwise used as cattle feed. Various solvent extracts showed the presence of oryzanols, tocols, and ferulic acid. Methanol was the most effective extractant under the optimized conditions of a material–solvent ratio of 1:15 (wt./vol.) and a time of extraction of 10 h. The yields of total phenols, oryzanols and ferulic acid from DRB with methanol were 2204, 316, and 233 ppm, respectively. Enrichment of antioxidants in the crude methanolic extract (CME) was achieved by sequential extraction and fractionation, resulting in three enriched fractions, viz., acetone extract (AE), acetone extract-lipophilic fraction (AE-LP) and acetone extract-polar fraction (AE-PP). While AE-LP was enriched in oryzanols and tocols by about 65 times, AE-PP was enriched in ferulic acid by 70 times as compared to their contents in DRB.