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Characterization and complete separation of major cyclolinopeptides in flaxseed oil by reversed‐phase chromatography
Author(s) -
Lao Ying W.,
Mackenzie Kim,
Vincent William,
Krokhin Oleg V.
Publication year - 2014
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201400193
Subject(s) - diastereomer , chemistry , chromatography , organoleptic , mass spectrometry , resolution (logic) , high performance liquid chromatography , phase (matter) , analytical chemistry (journal) , organic chemistry , food science , artificial intelligence , computer science
Organoleptic properties of flaxseed oil deteriorate during storage due to methionine oxidation in its major cyclolinopeptides. Cyclolinopeptide E was previously identified as being responsible for the manifestation of bitter taste with flaxseed oil ageing. We developed a chromatographic procedure to monitor the oxidation of major cyclic peptides in flaxseed oil. We also used liquid chromatography with mass spectrometry and high‐efficiency core–shell reversed‐phase sorbents to study the separation of cyclolinopeptides in detail. The Kinetex TM family of stationary phases (C 8 , C 18 , phenyl‐hexyl) was tested, along with the standard porous Luna TM C 18 (2) media. We found that only the phenyl‐hexyl stationary phase allows for complete resolution of major cyclolinopeptides, thus permitting direct UV monitoring of degree of conversion for cyclolinopeptide B into C and L into E. We also report, for the first time, a significant effect of peak splitting for some methionine S ‐oxide (Mso) containing cyclolinopeptides, which most likely appear due to diastereomerization. This results in poor separation efficiency for cyclolinopeptides F, G, and E, and gives baseline resolution of diastereomeric pairs for cyclolinopeptides I and P. Thus, a single oxidation of cyclolinopeptide N yields three distinct chromatographic peaks corresponding to cyclolinopeptide T (cyclo‐MsoLMPFFWV, reported for the first time) and pair of cyclolinopeptide I (cyclo‐MLMsoPFFWV) diastereomers.