Optimization of ABTS radical cation assay specifically for determination of antioxidant capacity of intracellular extracts of microalgae and cyanobacteria

► Improved method for antioxidant assay in microalgal extracts for use as food additives. ► Optimization of whole sample preparation and assay. ► Response to complete antioxidant profile, including both hydrophilic and hydrophobic species. ► Validation with four representative strains of GRAS microalgae and cyanobacteria. ► Usefulness in design/processing of functional foods enriched in natural antioxidants.