Mastocarpus Stellatus Research Articles

Ireland on a Plate: Curating the 2011 State Banquet for Queen Elizabeth II

Ireland on a Plate: Curating the 2011 State Banquet for Queen Elizabeth II

Hybrid carrageenan‐based formulations for edible film preparation: Benchmarking with kappa carrageenan

ABSTRACTAn intense search for new renewable sources to produce natural polymers for edible and biodegradable packaging is observed as they offer lower environmental costs. The objective of this work is to investigate the use of hybrid carrageenan, extracted from Mastocarpus stellatus seaweeds, as an alternative to commercial kappa carrageenan in new edible film formulations. To this end, the production and characterization of biodegradable films obtained with mixtures of rice starch and hybrid carrageenan or commercial kappa carrageenan were carried out. Thin, flexible, and transparent films with attractive functional properties were obtained from rice starch–carrageenan mixtures. Films forming solutions produced with hybrid carrageenan showed rheological properties comparable to commercial kappa carrageenan‐based solutions. Films formulated with hybrid carrageenan show significantly enhanced UV barrier, oxygen barrier, and hydrophobic properties. Thus, hybrid carrageenan proved to be a promising material for the production of edible coatings and biodegradable films and a good alternative to kappa carrageenan for such application. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42263.

On the bioremediation efficiency of Mastocarpus stellatus (Stackhouse) Guiry, in an integrated multi-trophic aquaculture system

The potential of rearing the red seaweed Mastocarpus stellatus (Stackhouse) Guiry, a carrageenophyte, as a biofilter in a pilot-scale, integrated multi-trophic aquaculture (IMTA) system was investigated. From April to June, M. stellatus, collected from a population in the north of Portugal was cultivated in 1200-L tanks in two consecutive, 4-week experiments with nutrient-enriched waters derived from fish tanks. The stocking density of 3 kg m−2 provided the best yields, ranging from 29.6 g dw m−2 day−1 in April–May to 38.9 g dw m−2 day−1 in June. In the April–May period, a linear increase in the yields was found at higher densities. M. stellatus growth rates during April–May period did not diverge significantly between stocking densities and reached a mean relative growth rate of 3.09 ± 0.90 % day−1 in April–May and 4.02 ± 0.43 % day−1 in June at 3 kg m−2. In June, the increase in stocking density negatively affected the growth rates (3 < 2 < 1 kg m−2). M. stellatus used ammonium (TAN) as the main N source and the nutrient uptake efficiency was found to be similar between stocking densities, but highest in June. The seaweeds removed an average of 66.29 ± 3.57 μmol TAN L–1 in May and 84.49 ± 4.00 μmol TAN L–1 in June, which corresponded to the mitigation of 43.19 ± 1.61 and 49.00 ± 1.59 % of NH3 from the system, respectively. This study demonstrated the potential to effectively cultivate M. stellatus in an IMTA system.

Community composition of thePlanctomycetesassociated with different macroalgae

Insights into the diversity of marine natural microbial biofilms, as for example those developing at the surface of marine macroalgae, can be obtained by using molecular techniques based on 16S rRNA genes. We applied denaturing gradient gel electrophoresis (DGGE) with 16S rRNA genes-specific primers for Planctomycetes to compare the communities of these organisms developing on six different macroalgae (Chondrus crispus, Fucus spiralis, Mastocarpus stellatus, Porphyra dioica, Sargassum muticum, and Ulva sp.) sampled in spring 2012 in two rocky beaches in the north of Portugal. Planctomycetes can be one of the dominant organisms found in the epibacterial community of macroalgae, and we wanted to determine the degree of specificity and the spatial variation of these group. Shannon diversity indexes obtained from the comparison of DGGE profiles were similar in all the macroalgae, and in both sites, F. spiralis was the algae presenting lower Planctomycetes diversity, while M. stellatus and P. dioica from Porto showed the highest diversity. The analysis of DGGE profiles, including anosim statistics, indicate the existence of a specific Planctomycetes community associated with the algal host, likely independent of geographical variation. Sequencing of DGGE bands indicated that Planctomycetes communities were highly diverse, and some Operational Taxonomic Units seemed to be specifically associated with each macroalgae.

Impact of cultivation of Mastocarpus stellatus in IMTA on the seaweeds chemistry and hybrid carrageenan properties.

The biomass yield potential of Mastocarpus stellatus, a commercially attractive carrageenophyte for foods and pharmaceutics, was investigated by cultivating the seaweeds in the nutrient-rich outflow of a commercial fish farm. Results from two consecutive 4 weeks experiments indicate that the cultivation of this seaweed produces a mean biomass of 21 to 40.6 gDW m(-2) day(-1) depending on the time of the experiment. DRIFT and CP-MAS NMR analyses of seaweeds indicate that cultivation during May affected quantitatively the seaweeds chemistry, and thus the chemical and gelling properties of native extracts of kappa/iota-hybrid carrageenan (KI). Overall, algal growth leads to the production of more sulphated KI, the percentage increase varying between 27% and 44% for the two experiments. However, alkali treatment of seaweeds before extraction reduces the variations in gelling properties of KI induced by the algal growth. This study demonstrates the capacity of growing M. stellatus in an integrated multi-trophic aquaculture system for the sustainable production of high value polysaccharides.

Integral Mastocarpus stellatus use for antioxidant edible film development

Four sequential aqueous extracts (M1 to M4) were obtained from Mastocarpus stellatus at different temperatures. M1 (extracted at 3 °C overnight) showed higher extraction yield and antioxidant activity than M2 (extracted at 45 °C for 45 min). Extracts M3 and M4, obtained both at 91 °C, were composed predominantly of a κ/ι-hybrid carrageenan. M4 contained higher protein proportion. Based on compositional and structural properties, four films were developed: FM3, FM4, FM3 + M4 and FM3 + M4 + M1. FM4 was green colored, more opaque, and water resistant, stronger and slightly less stretchable than FM3. The mixture of M3 and M4 for film development resulted in a film with intermediate characteristics. The addition of M1 to FM3 + M4 provided mainly proteins and sulfated compounds, resulting in a more water resistant film, with suitable mechanical properties in both tensile and puncture test, and much higher antioxidant activity.

RETRACTED: Carrageenan: A natural seaweed polysaccharide and its applications

Polysaccharides have been gaining interesting and valuable applications in the food and pharmaceutical fields. As they are derived from the natural source, they are easily available, non-toxic, cheap, biodegradable and biocompatible. Carrageenan is one among them, which fulfills the criteria of polysaccharide; it is a natural carbohydrate (polysaccharide) obtained from edible red seaweeds. The name Carrageenan is derived from the Chondrus crispus species of seaweed (Rhodophyceace) known as Carrageen Moss or Irish Moss, and Carraigin. A demand based on its application has been widely increasing in food and pharmaceutical sectors. Carrageenan has gained wide applications in experimental medicine, pharmaceutical formulations, cosmetics, and food industries. Through keen references of the reported literature on carrageenan, in this review, we have described about carrageenan, its properties, extraction and refining, and its food and pharmaceutical applications.

Bioactivity of sulfated polysaccharides from the edible red seaweed Mastocarpus stellatus

Abstract Carrageenans are typical sulfated-galactans from red seaweeds. Their main biological properties as antioxidants and anticoagulants were studied in vitro in Mastocarpus stellatus . On sequential extraction with cold-water (F1), hot-water (F2), acid (F3) and alkali (F4), four soluble polysaccharide fractions plus an insoluble cellulose residue (F5) were obtained. Composition was assessed by gas–liquid chromatography, ion chromatography and Fourier Transform Infrared (FTIR-ATR) spectroscopy. Multifunctional antioxidant capacity was assayed by FRAP- reducing power, ABTS- and photochemiluminiscence (PCL)- radical scavenging methods. Heparin-like anticoagulant capacity was studied by intrinsic-APTT and extrinsic-PT pathways. Recovery of F1–F4 yielded almost 60%, which main components were: neutral sugar (21.2–34.7 g/100 g), sulfate (0.6–3.9 g/100 g), protein (0.1–3.4 g/100 g) and uronic acid (0.9–2.7 g/100 g). Galactose (70.2–95.2 mol/100 g) was the predominant sugar in F1–F4 and sulfate their main inorganic anion (75–80% of total). F1–F3 contained the bulk of carrageenans. Degree of sulfation ranged from 0.22 (F1) to 0.03 (F3), respectively. Typical absorption bands of kappa-/iota-carrageenans at 930, 845 and 805 cm −1 assigned respectively to 3,6-anhydro-galactose, galactose-4-sulfate and 3,6-anhydro-galactose-2-sulfate appeared in FTIR spectra. Upon extraction with acid and alkali polymerization degree decreased significantly meanwhile iota- versus kappa-carrageenan increased. The highest FRAP-reducing power (44.9 μmol Trolox equivalents/g) and ABTS-radical scavenging ability was shown for cold-water soluble F1. Regarding anti-coagulant capacity, again F1 showed the best values (28 mg heparin equivalents/g), suggesting that its higher sulfate content associated to its high MW might exert a positive effect. Sulfate played a determinant role as antioxidant and anticoagulant, but a high MW was also relevant for the anticoagulant capacity of M. stellatus carrageenans.

Enzyme-assisted extraction of κ/ι-hybrid carrageenan from Mastocarpus stellatus for obtaining bioactive ingredients and their application for edible active film development

Two hydrolysates were obtained from dried Mastocarpus stellatus using alcalase. The phenolic content was partially removed from one of them. The phenolic-partially-removed hydrolysate (H) was found to be a potent angiotensin-I converting enzyme (ACE) inhibitor. However, the phenolic-containing hydrolysate (Hp) showed a higher Folin-reactive substance content and antioxidant capacity (reducing power and radical scavenging capacity). Hp was therefore selected for the development of antioxidant Mastocarpus carrageenan-based films. F-Hp0 (without the hydrolysate), F-Hp15 (with 15% hydrolysate) and F-Hp30 (with 30% hydrolysate) films were developed. κ/ι-hybrid carrageenan was the main film constituent and hydrolysate addition resulted in an increased sulfated proportion, higher protein content and higher number of hydrogen bonds. Therefore interactions between carrageenan helices, plasticizers and peptides in the film-forming solution were enhanced, especially in F-Hp15, and consequently the water vapour permeability (WVP) of the resulting film decreased. Nevertheless, F-Hp30 considerably improved the transparency, UV/Vis light barrier, water resistance and elongation at break (EAB). The presence of Hp increased both puncture force (F) and puncture elongation (E), but not tensile strength (TS) or Young's modulus (Y). The addition of an increased concentration of hydrolysate to the films led to a considerable increase in the Folin-reactive substance content and the antioxidant activity, especially the radical scavenging capacity.

Behind the scenes of Scottish researches into agar supply during the 1940s

Attention is drawn to correspondence in the Sheina Marshall archive at Millport concerning wartime efforts, led by Andrew Picken Orr, to find a satisfactory substitute for Japanese agar for bacteriological and other strategic commercial uses. The practical difficulties of finding, collecting and drying the considerable quantities of red seaweed (notably Mastocarpus stellatus (syn. Gigartina stellata) and Chondrus crispus) needed for a range of applications are evident in the correspondence, as was the need for confidentiality. Research funding was also an issue. International rivalries (as between Eire and the United Kingdom) are apparent, as are inter-departmental and inter-personal frustrations at a time of national emergency. Commercial production of British agar from these seaweeds was to be undertaken by the manufacturing firm of Paines and Byrne in Middlesex. As a result of the experimental researches at Millport, royalties under that firm's protected patent for the agar production process were negotiated for Orr and Marshall.

Contribution of biofilm to ecosystem functioning in rock pools with different macroalgal assemblages

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 482:69-79 (2013) - DOI: https://doi.org/10.3354/meps10238 Contribution of biofilm to ecosystem functioning in rock pools with different macroalgal assemblages Claire Golléty1,2,*, Tasman P. Crowe1 1School of Biology and Environmental Science, Science Centre West, University College Dublin, Belfield, Dublin 4, Ireland 2Sediment Ecology Research Group, Scottish Oceans Institute, University of St. Andrews, East Sands KY16 8LB, UK *Email: cg91@st-andrews.ac.uk ABSTRACT: Research into the role of biodiversity in the functioning of rocky shore ecosystems has ignored the microscopic component of the biota, in particular the microbial films coating most marine surfaces. Yet in other habitats, biofilms are known to be major contributors to ecosystem functioning. The objective of the present study was thus to understand the contribution of epilithic biofilms to rock pool metabolism (oxygen fluxes) and to identify whether this varies under different macroalgal assemblages. A 2-way factorial experiment was run in artificial rock pools on a moderately exposed rocky shore, combining different macroalgal treatments with the presence/ absence of biofilm. Biofilm made significant contributions to rock pool community primary productivity and rock pool residual respiration (rock pool metabolism measured without the macroalgal treatment), independently of the composition of the overlying macroalgal treatment. In rock pools with no macroalgae, biofilm appeared to dominate community metabolism, while the planktonic community was a minor contributor. There was no evidence of any significant effect of the different macroalgal assemblages tested on the metabolism of the biofilm. The presence of both Mastocarpus stellatus and Fucus serratus in pools, however, resulted in a lower photosynthetic activity of the biofilm than any of the other macroalgal treatments. Our results suggest that biofilm is a compartment that contributes significantly to the functioning of rock pool ecosystems, whether in terms of its heterotrophic or autotrophic activity, and should thus be taken into account in future research on these ecosystems. KEY WORDS: Microbial film · Metabolism · Rock pool · Macroalgae · Oxygen fluxes · Photosynthetic efficiency Full text in pdf format PreviousNextCite this article as: Golléty C, Crowe TP (2013) Contribution of biofilm to ecosystem functioning in rock pools with different macroalgal assemblages. Mar Ecol Prog Ser 482:69-79. https://doi.org/10.3354/meps10238 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 482. Online publication date: May 22, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.

Carrageenan: a review

Carrageenan is a natural carbohydrate (polysaccharide) obtained from edible red seaweeds. The name Carrageenan is derived from the Chondrus crispus species of seaweed known as Carrageen Moss or Irish Moss in England, and Carraigin in Ireland. Carraigin has been used in Ireland since 400 AD as a gelatin and as a home remedy to cure coughs and colds. It grows along the coasts of North America and Europe. Carrageenans are used in a variety of commercial applications as gelling, thickening, and stabilising agents, especially in food products and sauces. Aside from these functions, carrageenans are used in experimental medicine, pharmaceutical formulations, cosmetics, and industrial applications. &amp;nbsp;

Tailoring kappa/iota-hybrid carrageenan from Mastocarpus stellatus with desired gel quality through pre-extraction alkali treatment

Mastocarpus stellatus seaweeds were subjected to different alkali pre-treatments to investigate the effect of alkali type, concentration and treatment duration on the chemical structure and the gelling properties of extracted kappa/iota-hybrid carrageenan (KI). Increasing the concentration in KOH and the pre-treatment time gives KI with lower amounts of nu-carrageenan units, which have a direct impact on the improved gelling properties. However, excessive KOH concentration and pre-treatment duration give KI with smaller molecular mass and depressed gel properties. NaOH is more efficient in converting nu-carrageenan to iota-carrageenan, but no correlation between the chemical structure and gel properties was found. An interaction between the alkali concentration and the pre-treatment duration complicates the rationalization of NaOH efficiency. A set of KI with 60–75 mol% kappa-carrageenan and tailored gelling properties for a wide range of applications is delivered.

Qualitative and quantitative analysis of carrageenan content in gametophytes of Mastocarpus stellatus (Stackhouse) Guiry along Galician coast (NW Spain)

Qualitative and quantitative differences in carrageenan composition of gametophytes of the rhodophyte Mastocarpus stellatus (Gigartinales) were observed in this study. Carrageenans in gametophytes belong to the kappa family (κ-, ι-, ν-, μ-carrageenan). The dominant fractions were κ- and ι-carrageenan (more than 80 % of the total carrageenans). Mean total carrageenan content in gametophytes was of 37.32 ± 1.21 % DW. Spatial and seasonal variations were observed, mainly related to changes on environmental and oceanographic factors and the role of carrageenans in adapting the fronds to these changes. Maximum values in carrageenan content were observed for San Roman (Biscay Bay) in May and for Laxe and Mougas (Atlantic coast) in June. The results of this study indicated that spatial differences in carrageenan content were due to interactions of different factors, rather than the effect of a single factor. Fronds from San Roman had higher carrageenan content (43.23 ± 1.87 % DW) than those collected at two sites of the Atlantic coast, Mougas and Laxe (32.20 ± 1.14 % DW). San Roman is exposed to the open sea, windy and oriented to the north, and the water temperature is higher in summer than in the Atlantic coast. However, seasonal variations in carrageenan content resulted to be more related to other factors directly correlated with the input of energy in the ecosystems (irradiance, sunshine hours and insolation). Thus, carrageenan content began to increase in early spring when the number of sunlight hours increased. Maximum values were reached in late spring or early summer, just before maximum values of irradiance and air temperature were achieved.

A physicochemical study of Al(+3) interactions with edible seaweed biomass in acidic waters.

In this article, a study of the Al(+3) interactions in acidic waters with biomass of different edible seaweeds: brown (Fucus vesiculosus, Saccorhiza polyschides), red (Mastocarpus stellatus, Gelidium sesquipedale, Chondrus crispus), and green (Ulva rigida, Codium tomentosum), has been performed. The influence of both, the initial concentration of metal and the solution pH, on the Al-uptake capacity of the biomass has been analyzed. From preliminary tests, species Fucus vesiculosus and Gelidium sesquipedale have been selected for a more exhaustive analysis. Sorption kinetic studies demonstrated that 60 min are enough to reach equilibrium. The intraparticle diffusion model has been used to describe kinetic data. Equilibrium studies have been carried out at pH values of 1, 2.5, and 4. Langmuir isotherms showed that the best uptake values, obtained at pH 4, were 33 mg/g for F. vesiculosus and 9.2 mg/g for G. sesquipedale. These edible seaweeds have been found particularly effective in binding aluminum metal ions for most of the conditions tested. Physicochemical data reported at these low pH values could be of interest, not only in modeling aluminum-containing antacids-food pharmacokinetic processes produced in the stomach (pH values 1 to 3) but in remediation studies in acidic waters. Aluminum is thought to be linked to neurological disruptions such as Alzheimer's disease. In this article, the adsorption ability of different types of edible seaweeds toward aluminum has been studied. The choice of low pH values is due to the fact that stomach region is acidic with a pH value between 1 and 3 as a consequence of hydrochloric secretion; so physicochemical data reported in this study could be of interest in modeling drug-food interactions, in particular those referring to aluminum-containing antacids-food pharmacokinetic processes produced in the gastrointestinal tract.

A MOLECULAR PHYLOGENY OF ACROCHAETE AND OTHER ENDOPHYTIC GREEN ALGAE (ULVALES, CHLOROPHYTA)(1).

A molecular phylogeny was reconstructed from a culture collection of >150 isolates of epi-endophytic and endophytic green algae, based on nucleotide sequences of the plastid tufA and nuclear ITS2 loci. The cultures were isolated from a variety of algal hosts, notably the red algae Chondrus crispus, Mastocarpus stellatus, and Osmundea species, and the brown algae Chorda filum and Fucus serratus. The phylogeny revealed that in the Ulvales the majority of isolates fell into Acrochaete (Ulvellaceae), Ulva (Ulvaceae), Bolbocoleon (Bolbocoleaceae), and at least two unknown genera provisionally assigned to the Kornmanniaceae. Acrochaete was monophyletic. The genus was also more specious than previously described with 12 species, including up to six new species awaiting formal description. Isolates identified as Acrochaete repens, the type species of the genus, were polyphyletic. The remainder of the isolates were placed in the Ulotrichales. The results confirm that the endophytic habit supports a broad diversity of algal taxa and suggest that blade formation is a relatively recent innovation within the green algae.

Effect of the red seaweed Mastocarpus stellatus intake on lipid metabolism and antioxidant status in healthy Wistar rats

Health-promoting effect of dietary supplementation with the red seaweed Mastocarpus stellatus was studied. Its major component is dietary fibre (31.7/100g dry weight), 72% as soluble fibre, mainly formed by carrageenans, sulphated-galactans of red seaweeds. Thus, rats were fed either a basal- or an algal-supplemented diet (10%). Then, lipid metabolism was assessed in serum, and reducing power measured in serum and caecum by FRAP method. Also, caecal pH was monitored and short chain fatty acids analysed by gas–liquid chromatography. Seaweed intake reduced significantly triglycerides and total cholesterol in healthy rats, but not atherogenic index. Also, a significant increase in caecal moisture and proportion of acetic and propionic acids was obtained but no clear prebiotic effect was shown. Sulphated-galactans seemed to be related to the antioxidant status improvement in caecum and also to the 1.7-fold increase in anticoagulant capacity of plasma. Therefore, Mastocarpus could be regarded as a source of functional ingredients but its health benefits need to be further explored depending on specific use.

Comparing the ability of a non-indigenous and a native seaweed to induce anti-herbivory defenses

Phenotypic plasticity could be a key mechanism of successful species invasion. Few studies, however, have evaluated whether a non-indigenous species induces anti-herbivore defenses after its introduction to new habitats. We tested how a non-indigenous (Mastocarpus stellatus) and a native red seaweed (Chondrus crispus) responded to grazing by a periwinkle (Littorina littorea) and an isopod (Idotea granulosa) in Helgoland, Germany. In the donor region of the Mastocarpus population, that is Iceland, the periwinkle is missing, whereas the isopod is present. Our results indicate that Mastocarpus experienced less consumption by Littorina (but not by Idotea) than Chondrus. Moreover, Mastocarpus induced defenses in response to Idotea (but not to Littorina) grazing, whereas Chondrus induced anti-herbivory responses to both species of herbivores. Grazed Mastocarpus grew equally to non-grazed conspecifics, while growth of grazed Chondrus was lower than of ungrazed conspecifics. Hence, the non-indigenous Mastocarpus responded differently to grazing stress than the native Chondrus with respect to anti-herbivory and compensatory responses, which perhaps supported the successful Mastocarpus establishment in a new range.

Population ecology of Palmaria palmata (Palmariales, Rhodophyta) from harvested and non-harvested shores on Digby Neck, Nova Scotia, Canada

Population ecology of Palmaria palmata is described from the intertidal zone of Digby Neck and adjacent islands of Nova Scotia. The primary objectives were: to evaluate the difference in habitat specialization and population structure of P. palmata between harvest and non-harvest shores, and to characterize differences in thallus structure and frond sizes between epilithic and epiphytic populations. Harvest shores were gently sloping boulder fields with boulders typically about 0.5-1.0 m with dense cover of P. palmata on many of the rocks. Non-harvest shores (with or without P. palmata) consisted of boulders that were smaller or larger than harvest shores, or bedrock; when P. palmata was present on nonharvest sites it was typically epiphytic on other algae (e.g., Fucus spp., Mastocarpus stellatus, Devaleraea ramentacea). Harvestable epiphytic populations occurred only in high current areas. While there was little difference in average cover of P. palmata harvest and non-harvest shores ( vs. , mean standard deviation [SD]), the cover of P. palmata on harvest shores was highly skewed such that individual boulders often had >90% cover while adjacent rocks had little. Frond length of large fronds was greater on harvested shores, and mean frond density () was three times higher than the mean density on the non-harvested shores. Frond lengths of entire epiphytic and epilithic frond complements of 119 thalli from harvest beaches showed no difference in mean size of the largest fronds, and no difference in frond number per holdfast when epiphytic and epilithic thalli were compared.

Molecular weight distribution of polysaccharides from edible seaweeds by high-performance size-exclusion chromatography (HPSEC)

Biological properties of polysaccharides from seaweeds are related to their composition and structure. Many factors such as the kind of sugar, type of linkage or sulfate content of algal biopolymers exert an influence in the relationship between structure and function. Besides, the molecular weight (MW) also plays an important role. Thus, a simple, reliable and fast HPSEC method with refractive index detection was developed and optimized for the MW estimation of soluble algal polysaccharides. Chromatogram shape and repeatability of retention time was considerably improved when sodium nitrate was used instead of ultrapure water as mobile phase. Pullulan and dextran standards of different MW were used for method calibration and validation. Also, main polysaccharide standards from brown (alginate, fucoidan, laminaran) and red seaweeds (kappa- and iota-carrageenan) were used for quantification and method precision and accuracy. Relative standard deviation (RSD) of repeatability for retention time, peak areas and inter-day precision was below 0.7%, 2.5% and 2.6%, respectively, which indicated good repeatability and precision. Recoveries (96.3–109.8%) also showed its fairly good accuracy. Regarding linearity, main polysaccharide standards from brown or red seaweeds showed a highly satisfactory correlation coefficient (r>0.999). Moreover, a good sensitivity was shown, with corresponding limits of detection and quantitation in mg/mL of 0.05–0.21 and 0.16–0.31, respectively. The method was applied to the MW estimation of standard algal polysaccharides, as well as to the soluble polysaccharide fractions from the brown seaweed Saccharina latissima and the red Mastocarpus stellatus, respectively. Although distribution of molecular weight was broad, the good repeatability for retention time provided a good precision in MW estimation of polysaccharides. Water- and alkali-soluble fractions from S. latissima ranged from very high (>2400kDa) to low MW compounds (<6kDa); this high heterogeneity could be attributable to the complex polysaccharide composition of brown algae. Regarding M. stellatus, sulfated galactans followed a descending order of MW (>1400kDa to <10kDa), related to the different solubility of carrageenans in red seaweeds. In summary, the method developed allows for the molecular weight analysis of seaweed polysaccharides with very good precision, accuracy, linearity and sensitivity within a short time.