Comparative antioxidant potential, proximal biochemical composition, and pigment content of 11 brown seaweeds from the West of Ireland

The biorefinery and valorisation of sustainable bioresources such as seaweeds have increased in response to global circular economy initiatives. Several seaweed species are exploited worldwide in the biofertilizer, nutrition, bioenergy, cosmetics, or pharmaceutical sectors. Brown seaweeds are widespread, easily accessible, and abundant in northwest Europe regions, with some species being commercially harvested and processed. Here, both commercially exploited, and less studied brown seaweeds (n = 11) were collected from Irelands Atlantic coast and analysed for soluble carbohydrates, lipids, proteins, fatty acid, and pigment profiles as well as antioxidant potential. Soluble carbohydrates (62.7 µg glucose eq mg⁻¹ DW) were highest in Saccharina latissima while lipids (148.2 mg L g⁻¹ DW), fucoxanthin (1.35 mg g⁻¹) and β-carotene (4.10 mg g⁻¹) were greater in Dictyota dichotoma. The highest antioxidant activity (456.3 µmol Trolox eq mg⁻¹ DW with TEAC assay) and soluble protein content (562.5 µg BSA eq mg⁻¹ DW) were in Halidrys siliquosa extracts. Data matrix multivariate ordination indicated that some less studied brown seaweeds have further valorisation potential owing to their biochemical composition and bioactivity. The development of species-specific tailored cultivation strategies as part of integrated multi-trophic aquaculture systems has potential to contribute to environmental sustainability while introducing new natural bioactive products to markets.