Biochemical Composition of Six Native Seaweeds from Buarcos Bay, Central West Coast of Portugal

Abstract

Seaweeds have a great variety of compounds with different properties and benefits to human health. Marine macroalgae provide a high nutritional value along with low caloric value, poor in fat, and with the presence of polysaccharides that behave as fibers with no calories. This is not widespread, but some macroalgae and by-products are used in various applications, inclusively in food products. Under the project MENU - Marine Macroalgae: Alternative recipes for a daily nutritional diet, six native seaweed species were collected in Praia da Tamargueira, Buarcos, Figueira da Foz, Portugal: Ulva spp. (green seaweed), Chondrus crispus, Gracilaria gracilis, Mastocarpus stellatus, Porphyra umbilicalis (red seaweeds) and Bifurcaria bifurcata (brown seaweed) to further biochemical characterization. Polysaccharides’ monomeric composition was determined after sulphuric acid hydrolysis, derivatization to alditol acetates, then analyzed by gas chromatography with flame ionization detector (GC-FID), whereas protein content was quantified following colorimetric Bradford method. Results showed red seaweeds presenting the highest polysaccharide profile followed by the green macroalgae and then the brown seaweed species. In the case of protein content, Porphyra umbilicalis was the seaweed with the highest content, followed by Ulva spp., Gracilaria gracilis, Chondrus crispus and Mastocarpus stellatus. The brown seaweed Bifurcaria bifurcata presented the lowest protein content.