Effect of high pressure homogenization on microstructural and rheological properties of A. platensis, Isochrysis, Nannochloropsis and Tetraselmis species

The rich nutritional profile of microalgae biomass has made it a promising clean label food ingredient that has the potential to fortify incorporated food with simultaneous modification of the structural properties. This work investigated the effect of high pressure homogenization (HPH) at 300, 600, and 900 bar on the microstructural and rheological properties of four microalgal suspensions, namely, Arthospira platensis, Isochrysis sp., Nannochloropsis sp., and Tetraselmis sp. HPH treatment resulted in the disintegration of microalgal cells, which altered the cell morphology, particle size, and rheological properties. A. platensis, Isochrysis sp., and Tetraselmis sp. showed a linear HPH intensity-dependent cell disintegration as evidenced by an increase in viscosity of the suspensions. While A. platensis exhibited the most pronounced effect of HPH treatment, Nannochloropsis sp. showed a minimal response that was attributable to its strong cell walls. The significant interspecies differences in the colloidal properties of the HPH-treated microagal suspensions coincided with the proportion of various nutrients where the fluctuation of lipids (between 8% and 17%) and proteins (between 10% and 57%) affected hydrophilic/hydrophobic interactions between the macromolecules. The findings demonstrate that HPH can be used to tailor microalgae biomass for specific food applications as potential structuring ingredients.

Automated summary

High pressure homogenization (HPH) has different effects on microalgal suspensions, with A. platensis, Isochrysis sp., and Tetraselmis sp. being more sensitive to HPH treatment while Nannochloropsis sp. is relatively insensitive. The colloidal properties of microalgal suspensions are influenced by the proportion of various nutrients, affecting hydrophilic/hydrophobic interactions between macromolecules.