Volatile Flavor Compositions and the Odorant Feature Analysis of Four Microalgae

Objective: Spirulina platensis, Neochloris oleoabundans, Phaeodactylum tricornutum and Isochrysis zhanjiangensis are common microalgae for food and feed. Their odors can affect the flavor of foods made from the aquaculture and farm animals through the food-chain transfer. This study aimed at analyzing the flavor characteristics of these four microalgae to provide fundamental data for the further researches of the relative foods. Methods: HS-SPME-GC-MS and electronic nose techniques were applied to identify the volatile compounds and the flavor profiles of the microalgae were analyzed thereafter. Results: In the four microalgae mentioned above, 33, 35, 23 and 29 volatile compounds were identified respectively. The results showed that hexanol, 1-octen-3-ol, (E,Z)-2,4-decadienal, (E)-2-nonenal and hexanal were the main compounds in S. platensis contributing to its grassy, earthy and fatty odor; (E,Z)-2,4-decadienal, (E,E)-2,4-decadienal, octanal, 1-octen-3-ol, hexanal and hexanol were the key volatile compounds in N. oleoabundans and gave it a flavor feature of fatty, earthy, fishy and grassy note; heptanal, naphthalene, octanal, hexanal and 1-octen-3-ol were the main volatile compounds in P. tricornutum contributing to its fatty odor; (E,Z)-2,4-decadienal, (E,E)-2,4-decadienal, 1-octen-3-ol, hexanol, hexanal and (E,E)-2,4-heptadienal were the primary volatile substances in I. zhanjiangensis giving it fatty, grassy and fishy odor. Conclusion: Hexanal, hexanol, 1-octen-3-ol and olefin/diolefin aldehyde with 7~10 carbon atoms are the main odorous compounds in the four microalgae, contributing to their grassy, earthy, fishy and fatty odorous feature.