Determination of lipophilic and hydrophilic bioactive compounds in raw and parboiled rice bran

Abstract

Rice bran is one of the most important rice by-products and represents about 10% of rice production. This rice fraction contains large amounts of bioactive compounds; because of that, the aim of this study was to investigate the impact of parboiling on the concentration of lipophilic bioactive compounds (fatty acids, tocols, γ-oryzanol and, free + esterified and bound sterols and triterpenic alcohols) and free and cell wall-bound phenolic compounds. Parboiling treatment caused changes in fatty acid composition and increased the total tocols and γ-oryzanol content. GC-qTOF-MS analysis of phytosterol and triterpenic alcohols allowed the determination of 14 compounds that were quantified in free and bound form; free phytosterol and triterpenic alcohol compounds represented 10 and 43% of the total fraction in raw and parboiled rice bran, respectively. The analysis of free and bound phenolic compounds was carried out by HPLC-DAD-TOF-MS. The TOF analyzer permitted the determination of 24 free and 27 bound phenolic compounds and, to our knowledge, some of them have been quantified for the first time in rice.