title: Changes in 4-vinylsyringol and other phenolics during rapeseed oil refining.
abstract: The aim of the present study was to examine changes in phenolic compounds during refining of rapeseed oil. In crude rapeseed oil, 4-vinylsyringol (canolol) is the dominant phenolic compound, accounting for 85% of total phenolics. Refining decreased the total amount of phenolic compounds by 90%. NMR and MS analyses of edible rapeseed oil phenolic extracts identified 4-vinylsyringol dimer as the dominant phenolic compound. This phenolic compound appears to form through acid-catalyzed dimerization-aromatic substitution of 4-vinylsyringol monomers. Analysis of rapeseed oils from different stages of the refining process suggest that 4-vinylsyringol dimer forms during the neutralization phase, when H3PO4 acts as a catalyst, or during bleaching, when acid-activated bleaching earth acts as the catalyst. Whether 4-vinylsyringol forms during one or the other phase appears to depend on the phospholipid content of the crude oil. These insights may be useful for designing rapeseed oil refining processes that maximize levels of 4-vinylsyringol dimer.
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia. Electronic address: kkraljic@pbf.hr.
authors.forename: Klara
authors.initials: K
authors.lastname: Kraljić
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia.
authors.forename: Dubravka
authors.initials: D
authors.lastname: Škevin
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia.
authors.forename: Lidija
authors.initials: L
authors.lastname: Barišić
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia.
authors.forename: Monika
authors.initials: M
authors.lastname: Kovačević
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia.
authors.forename: Marko
authors.initials: M
authors.lastname: Obranović
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Jurčević
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005229:Fatty Acids, Monounsaturated; D005504:Food Analysis; D005511:Food Handling / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D010938:Plant Oils / Q000737:chemistry*; D059808:Polyphenols / Q000032:analysis; D011748:Pyrogallol / Q000031:analogs & derivatives* / Q000032:analysis; D000074262:Rapeseed Oil; D053719:Tandem Mass Spectrometry
chemical_list: C509202:4-vinylsyringol; D005229:Fatty Acids, Monounsaturated; D010938:Plant Oils; D059808:Polyphenols; D000074262:Rapeseed Oil; D011748:Pyrogallol
keywords: 4-Vinylsyringol; 4-Vinylsyringol dimer; Phenolic compounds; Rapeseed oil; Refining