A comparative study on the metabolites profiling of linseed cakes from Egyptian cultivars and antioxidant activity applying mass spectrometry-based analysis and chemometrics.

Linseed (Linum usitatissimum L.) is an economically important crop worldwide. After the oil extraction, the cake is generated as a by-product. This study addresses an untargeted profiling of the cakes of four Egyptian cultivars of linseed via RP-HPLC-DAD-QTOF-MS and MS/MS. Totally, 162 metabolites were detected in the samples, being classified into hydroxybenzoic acids (20), hydroxycinnamic acids (20), flavonoids (59), lignans (9), coumarins (1), amino acids (8), peptides (3), cyanogenic glycosides (6), jasmonates (15), nucleosides (2), organic acids (16), and sugars (3). Upon employing principal component analysis and hierarchical cluster analysis, the cultivars were adequately grouped, suggesting that this approach can serve for origin traceability. Besides, the total phenol content and antioxidant activity were determined and in the same line with the previous results. As far as we know, this is the first comprehensive metabolic profiling of linseed cakes that gives a prospect of its relevance for the food industry.