Comparison of extraction methods for selected carotenoids from macroalgae and the assessment of their seasonal/spatial variation

•Comparison of extraction techniques for the recovery of carotenoids, xanthophylls and fucoxanthin from two brown macroalgae.•SLE produced the greatest yield of fucoxanthin.•Supercritical CO2 yielded extracts with the highest purity of fucoxanthin•Seasonal/spatial information on yields and purity for optimal harvest reported.

Natural bioactives are an excellent source of carotenoids for the production of nutraceuticals, functional foods and food additives. The extraction efficiencies of solid-liquid extraction (SLE), supercritical CO2, supercritical CO2 with ethanol as co-solvent for the recovery of the carotenoids, xanthophyll and fucoxanthin, from two brown macroalgae Fucus serratus and Laminaria digitata were explored. The extraction efficiency was measured using both purity and yield of target compounds. Solid liquid extraction (hexane/acetone (70:30) at 50 °C for 24 h produced the greatest yield of carotenoid rich extracts from F. serratus. Optimal conditions in terms of carotenoid yield using supercritical CO2 were 50 °C, 300 Atm with an extraction time of 60 min. SCO2 yielded a higher purity of fucoxanthin while SLE resulted in a higher purity of xanthophyll. Seasonal/spatial variation based on the purity and yield was also investigated to provide valuable information on optimal harvest time for these compounds.