Figure 1

Reference samples and chemical profiling scheme for the discovery of differential metabolic markers of chia, linseed and sesame seeds. (A) Reference seed batches (S_01 - S_28) that were marketed for human consumption were collected from local grocery stores (Berlin, Germany) with anonymized vendor information (Table S1). Note that two colour variants of each seed type were included. All seed batches except S_20 contained the seed coat. The colour code, chia (red), linseed (grey) and sesame (blue) is used throughout the study. (B) Chemical fractionation and chemical profiling scheme of reference seed material. Rapid direct profiling of volatile organic compounds (VOC) was performed by headspace solid phase micro-extraction gas chromatography – mass spectrometry (SPME-GC-MS). A solid fraction (SOL) was obtained after exhaustive extraction of soluble metabolites. Solids were hydrolyzed and components analyzed by chemical derivatization and GC-MS. A polar liquid extract (POL) that was enriched for primary and small specialized metabolites was analyzed by chemical derivatization and routine GC-MS profiling. Note that the lipophilic liquid extract was omitted, because seed processing for human consumption frequently involves seed defatting and/or addition of fats from other sources.