title: Determination of seleno-amino acids bound to proteins in extra virgin olive oils.
abstract: An analytical method has been developed to determine seleno-amino acids in proteins extracted from extra virgin olive oils (EVOOs). Different aqueous/organic solvents were tested to isolate proteins, an acetone:n-hexane combination being the best protein precipitant. In a first dimension chromatography, extracted proteins were analysed by size exclusion chromatography (SEC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) to identify S and Se associations as proteins marker. Two fractions of 66 kDa (A) and 443 kDa (B) were identified. These fractions were submitted to microwave-assisted acid hydrolysis (MAAH) to release seleno-amino acids. In a second dimension chromatography seleno-amino acids were determined by reversed-phase chromatography (RPC) coupled to ICP-MS. Seleno-methylselenocysteine was determined with values ranging from 1.03-2.03±0.2 μg kg(-1) and selenocysteine at a concentration of 1.47±0.1 μg kg(-1). Variations of protein and seleno-amino acid concentrations were observed between EVOO varieties, contributing to EVOO cultivar differentiation.
authors.affiliation: Instituto de Química de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, CP 5700 San Luis, Argentina.
authors.forename: Sabier
authors.initials: S
authors.lastname: Torres
authors.affiliation: Instituto de Química de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, CP 5700 San Luis, Argentina.
authors.forename: Raul
authors.initials: R
authors.lastname: Gil
authors.affiliation: Instituto de Biología Agrícola de Mendoza (IBAM-CONICET), Almirante Brown 500, Chacras de Coria CP 5505, Mendoza, Argentina. Electronic address: msilva@fca.uncu.edu.ar.
authors.forename: María Fernanda
authors.initials: MF
authors.lastname: Silva
authors.affiliation: Instituto de Química de San Luis (INQUISAL-CONICET), Chacabuco y Pedernera, CP 5700 San Luis, Argentina. Electronic address: ppacheco@unsl.edu.ar.
authors.forename: Pablo
authors.initials: P
authors.lastname: Pacheco
mesh_terms: D000069463:Olive Oil / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis*; D017279:Selenocysteine / Q000031:analogs & derivatives* / Q000032:analysis; D012997:Solvents / Q000737:chemistry
chemical_list: D000069463:Olive Oil; D010940:Plant Proteins; D012997:Solvents; D017279:Selenocysteine; C002979:selenomethylselenocysteine
keywords: LC–ICP MS; Olive oils; Proteins; Seleno-amino acids