Lipid oxidation induced protein scission in an oleogel as a model food.

[Display omitted] • Lipid induced scission peptides are located on the surface of the protein in random coil segments. • Scission is especially present at the N- and C-terminus of beta-lactoglobulin. • Cysteine and aliphatic amino acids were most important cleavage sites. • The α-amidation pathway was the predominant mechanism in this study. • The comparison of various oxidants of proteins are compared to their ability of protein scission and modification. Lipid oxidation induced protein scission was investigated in oleogel using beta-lactoglobulin (whey protein isolate) as gelator. Extracted cleaved peptides were measured using high resolution mass spectrometry (FT-ICR-MS), which was provided by an automatically generated annotation list approach to identify relevant masses and sum formula using the isotopic pattern. The identified oxidized peptides were then further evaluated using partial least squares regression to relevant lipid hydroperoxide formation data, which provide the significance and importance of the peptides toward lipid induced scission. Thereby, the most important peptides are located at the surface of the protein in random coil segments and especially at the ends of the protein sequence. The most important amino acids were cysteine and aliphatic amino acids, which undergo scission mostly by the α-amidation pathway. The findings compare well with studies investigating depletion of amino acids initiated by lipid oxidation in systems containing bovine albumin or gamma-globulin. [ABSTRACT FROM AUTHOR]