Determination of seleno-amino acids bound to proteins in extra virgin olive oils

Food Chem. 2016 Apr 15;197(Pt A):400-5. doi: 10.1016/j.foodchem.2015.10.008. Epub 2015 Oct 9.

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.

Keywords: LC–ICP MS; Olive oils; Proteins; Seleno-amino acids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Olive Oil / chemistry*
  • Plant Proteins / analysis*
  • Selenocysteine / analogs & derivatives*
  • Selenocysteine / analysis
  • Solvents / chemistry

Substances

  • Olive Oil
  • Plant Proteins
  • Solvents
  • Selenocysteine
  • selenomethylselenocysteine