title: Characteristics and antioxidative activity of the acetone-soluble and -insoluble fractions of a defatted rice bran extract obtained by using an aqueous organic solvent under subcritical conditions.
abstract: The defatted rice bran extracts obtained by being treated with various subcritical aqueous fluids at 230 °C for 5 min were further subjected to an acetone-solubilization treatment. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity depended on the total phenolic content of a sample, the acetone-soluble fraction of the extract obtained with 40% (v/v) aqueous acetone showing the highest activity. Based on the UV spectrometric and HPLC analyses, the substances with higher absorbance around 280 nm and higher hydrophobicity were found solubilizing out from the extracts into the acetone during fractionation. A gel permeation chromatographic analysis suggested that the extracts comprised monomeric or oligomeric substances. The antioxidative activity was evaluated by a DPPH radical scavenging activity analysis, rancidity test, and autoxidation analysis, revealing that it would be most likely to exert a radical scavenging effect more effectively during the initial stage of lipid oxidation than during the propagation stage.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Japan.
authors.forename: Tai-Ying
authors.initials: TY
authors.lastname: Chiou
authors.forename: Takashi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Shuji
authors.initials: S
authors.lastname: Adachi
mesh_terms: D000096:Acetone / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry; D002241:Carbohydrates / Q000032:analysis; D005511:Food Handling; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000494:pharmacology; D012275:Oryza / Q000737:chemistry*; D010636:Phenols / Q000032:analysis; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology; D010938:Plant Oils / Q000302:isolation & purification*; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D001713:Biphenyl Compounds; D002241:Carbohydrates; D016166:Free Radical Scavengers; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D010938:Plant Oils; D012997:Solvents; D014867:Water; D000096:Acetone; C004931:1,1-diphenyl-2-picrylhydrazyl