Analysis of carbonyl compounds in sea buckthorn for the evaluation of triglyceride oxidation, by enzymatic hydrolysis and derivatisation methodology

Carbonyl compounds formed in sea buckthorn berry (Hippophae rhamnoides) and oil samples as a result of lipid oxidation were determined by enzymatic hydrolysis followed by derivatisation with 2,4-dinitrophenylhydrazine and analysed by LC–UV and electrospray ionisation (ESI) tandem mass spectrometry (MS/MS). Several classes of carbonyl compounds such as saturated, unsaturated, linear and branched aldehydes and ketones, aromatic aldehyde, dicarbonyls and carboxy aldehydes were identified based on fragmentation pattern, molecular weight and retention time. The lower carbonyls such as formaldehyde, acetaldehyde and acetone were found to be predominant in the berry samples and acetaldehyde was found to be the most abundant carbonyl. In the sea buckthorn pulp oil sample, longer aldehydes and carboxy aldehydes dominated, thus clearly demonstrating the benefit of the enzymatic step when analysing oxidation products originating from triglycerides.