Changes in volatile and fatty acid compositions of selected microalgal suspensions with high pressure homogenization

This is the first report on the fatty acid and volatile analysis of high pressure homogenization (HPH)-treated microalgal suspensions using chemometrics methods to increase insight into the complex (bio)chemical changes. Four microalgal suspensions, namely Arthrospira, Isochrysis, Nannochloropsis, and Tetraselmis species, were pro-cessed by HPH at 300, 600, and 900 bar. While cell disruption due to HPH seemed to have a minimal impact on the fatty acid profile, the high number of discriminating volatiles suggest several (bio)chemical reactions that the treatment may have triggered. Alterations in terpene and ketones indicate the induction of carotenoid degra-dation. Lipid oxidation could also have occurred during HPH, as noted in the changes in furans in Arthrospira sp. and aldehydes in Nannochloropsis sp. and Tetraselmis sp. Maillard reaction may have likewise been triggered by HPH as shown by the pyrazines in Arthrospira sp. and Tetraselmis sp. Sulphur compounds were only significantly changing in Isochrysis sp. and are typically associated with the degradation of sulphur-containing amino acids. The abundance of hydrocarbons as discriminant volatiles suggests that HPH can induce the synthesis of long -chain fatty acids. This study provides insight into how the volatile profile of microalgae can potentially be manipulated by applying specific pressure levels of HPH.

Automated summary

This study presents the first report on the analysis of fatty acids and volatile compounds in high pressure homogenization (HPH)-treated microalgal suspensions using chemometrics methods. The findings indicate that HPH has minimal impact on the fatty acid profile but may trigger various (bio)chemical reactions such as carotenoid degradation, lipid oxidation, Maillard reaction, and synthesis of long-chain fatty acids. The results highlight the potential of manipulating the volatile profile of microalgae by controlling specific pressure levels of HPH.