title: Synthesis of steryl ferulates with various sterol structures and comparison of their antioxidant activity.
abstract: Steryl ferulates synthesised from commercial sterols as well as commercial oryzanol were used to better understand how structural features affect antioxidant activity in vitro by the ABTS(+) radical decolorization assay, by oxidative stability index (OSI) of soybean oil, and by analysis of antioxidant activity during frying. Steryl ferulates inhibited the ABTS(+) radical by 6.5-56.6%, depending on their concentration, but were less effective, especially at lower concentrations, than ferulic acid. Ferulic acid and steryl ferulates had either no effect, or lowered the OSI of soybean oil by up to 25%, depending on the concentration. In their evaluation as frying oil antioxidants, steryl ferulates with a saturated sterol group had the best antioxidant activity, followed by sterols with one double bond in the C5 position. The results indicate that a dimethyl group at C4 as well as a C9,C19 cyclopropane group, as found in oryzanol, negatively affects antioxidant activity in frying oils.
authors.affiliation: United States Department of Agriculture,(1) Agricultural Research Service, National Center for Agricultural Utilization Research, Functional Foods Research, 1815 N University Street, Peoria, IL 61604, United States. Electronic address: Jill.Moser@ars.usda.gov.
authors.forename: Jill K
authors.initials: JK
authors.lastname: Winkler-Moser
authors.affiliation: United States Department of Agriculture,(1) Agricultural Research Service, National Center for Agricultural Utilization Research, Functional Foods Research, 1815 N University Street, Peoria, IL 61604, United States.
authors.forename: Hong-Sik
authors.initials: HS
authors.lastname: Hwang
authors.affiliation: United States Department of Agriculture,(1) Agricultural Research Service, National Center for Agricultural Utilization Research, Functional Foods Research, 1815 N University Street, Peoria, IL 61604, United States.
authors.forename: Erica L
authors.initials: EL
authors.lastname: Bakota
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Midwest Area, 1815 N University Street, Peoria, IL 61604, United States.
authors.forename: Debra A
authors.initials: DA
authors.lastname: Palmquist
mesh_terms: D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry*; D003373:Coumaric Acids / Q000737:chemistry; D015394:Molecular Structure; D010666:Phenylpropionates / Q000737:chemistry; D010840:Phytosterols / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D003373:Coumaric Acids; D010666:Phenylpropionates; D010840:Phytosterols; C004999:ferulic acid; C013172:gamma-oryzanol
keywords: Antioxidant activity; Antipolymerisation activity; Frying; Phytosterols; Soybean oil; Steryl ferulates