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LC–MS investigations on interactions between isolated β-lactoglobulin peptides and lipid oxidation product malondialdehyde
- Gürbüz, Göker, Heinonen, Marina
- Food chemistry 2015 v.175 pp. 300-305
- beta-lactoglobulin, detectors, electrospray ionization mass spectrometry, fluorescence, lipid peroxidation, liquid chromatography, malondialdehyde, peptides, schiff bases
- Interactions between secondary lipid oxidation product malondialdehyde (MDA) and selected β-lactoglobulin (β-Lg) peptides were investigated. Selected tryptic peptides of β-Lg (ALPMHIR, LIVTQTMK and VLVLDTDYK) were fractionated via preparative-HPLC and incubated with MDA at 37°C and 60°C for 7days. Changes in samples were monitored with LC-ESI-MS coupled with UV and fluorescence detectors. Prominent modifications in peptide samples included formation of two distinct types of MDA adducts observed with mass increments of 54 and 134amu, corresponding to Schiff base and dihydropyridine (DHP)-type adducts, respectively. Modified peptides with m/z +54amu were more stable at 37°C than at 60°C but showed more rapid formation than compounds with m/z +134amu. MDA-peptide adducts resulting in +134amu mass increment displayed strong fluorescent characteristics and they were more stable than Schiff base adducts at 60°C.