Characterizing and decoding the key odor compounds of Spirulina platensis at different processing stages by sensomics

Processing is an indispensable technology in the preparation of Spirulina platensis ( S. platensis ). The key odorants in liquids, muds, and powders from S. platensis (NM and GZ) were characterized. A total of 90 odorants were identified and 41 odorants were sniffed with the flavor dilution (FD) factors ranging from 1 to 729. Among them, nonanal, decanal, d -limonene, β -cyclocitral, and β -ionone with FD factors ≥1 were detected in S. platensis during the whole processing stages. In addition, heptanal, ( E , E )-2,4-nonadienal, trans -4,5-epoxy-( E )-2-decenal, 1-hepten-3-one, isophorone, 3-ethyl-2,5-dimethylpyrazine, and α -ionone exhibited higher odor activity values in powders; β -myrcene, methional, and S -methyl methanethiosulphonate were key odorants in muds; while trans -3-penten-2-ol was key odorant in liquids. Besides, the GZ-mud presented stronger earthy and fishy odor than NM - mud. S. platensis powders have the stronger grassy odor, roasted odor, and marine odor than S. platensis muds. Overall, drying process promotes the formation of aldehydes, heterocyclic compounds, and terpenoids.