Seaweed Species Research Articles

Bioactive nanoparticles derived from marine brown seaweeds and their biological applications: a review.

The biosynthesis of novel nanoparticles with varied morphologies, which has good implications for their biological capabilities, has attracted increasing attention in the field of nanotechnology. Bioactive compounds present in the extract of fungi, bacteria, plants and algae are responsible for nanoparticle synthesis. In comparison to other biological resources, brown seaweeds can also be useful to convert metal ions to metal nanoparticles because of the presence of richer bioactive chemicals. Carbohydrates, proteins, polysaccharides, vitamins, enzymes, pigments, and secondary metabolites in brown seaweeds act as natural reducing, capping, and stabilizing agents in the nanoparticle's synthesis. There are around 2000 species of seaweed that dominate marine resources, but only a few have been reported for nanoparticle synthesis. The presence of bioactive chemicals in the biosynthesized metal nanoparticles confers biological activity. The biosynthesized metal and non-metal nanoparticles from brown seaweeds possess different biological activities because of their different physiochemical properties. Compared with terrestrial resources, marine resources are not much explored for nanoparticle synthesis. To confirm their morphology, characterization methods are used, such as absorption spectrophotometer, X-ray diffraction, Fourier transforms infrared spectroscopy, scanning electron microscope, and transmission electron microscopy. This review attempts to include the vital role of brown seaweed in the synthesis of metal and non-metal nanoparticles, as well as the method of synthesis and biological applications such as anticancer, antibacterial, antioxidant, anti-diabetic, and other functions.

Lipid Characterization of Beach-Cast Seaweeds from Gran Canaria Island: Potential Use in Human and Animal Nutrition

Macroalgal wracks can be considered unpleasant for beach users and, consequently, they are usually collected from most touristic beaches and discarded. However, seaweeds are an important source of bioactive lipid compounds, such as phospholipids, glycolipids, and n-3 polyunsaturated fatty acids (n-3 PUFA), displaying multiple health-promoting properties, including antioxidant and antimicrobial activities. The aim of this study is to characterize the lipid composition of twelve marine seaweed species (two green, six red, and four brown species) from macroalgal wracks of Gran Canaria Island, and to evaluate their potential use for several purposes, including human and animal nutrition. Lipid content, lipid classes, and fatty acid profiles of isolated specimens from the macroalgal wracks were determined. Lipid contents ranged between 0.27 and 3.17% of dry weight, with all species showing high phytosterols proportions and balanced omega-6/omega-3 (n-6/n-3) ratios. In addition, Cymopolia barbata, Asparagopsis sp., and Hypnea spinella seem to be an attractive source of both mono- and di-galactosyl-diacylglycerols, while A. stellata, Jania sp., and Lobophora sp. are relatively rich in n-3 LC−PUFA. Finally, both green algae showed the most favorable values for the nutritional indicators of cardiovascular health promotion. Overall, the macroalgal species analyzed could be considered as interesting sources for human and animal nutrition.

Seaweed Extract for Sustainable Rice Production- A Review

Seaweed extract is a bio-simulant that obtain from seaweeds like Agar, and Alginate and many more species of seaweed. By application of seaweed extract in rice crop (Oryza sativa L.) can increase the growth, grain yield, biological yield and improves the nutrient content in grain. Seaweed extract application also reduces the biotic and abiotic stress on crops. This seaweed extract can be applied in many ways to crop plants like foliar spray, soil incorporation, etc., based on crop type. It can impact the cellular respiration of plants and incorporates many enzymes like NAA, auxins, vitamins, cytokinin’s and many other growths promoting hormones in plants. This extract also has growth stimulating properties. It can increase nutrient absorption capacity by increasing root growth. Most of the marine algae are rich in auxins that increase root growth. The application of seaweed extract in soil can improve the physical, chemical, and biological properties of the soil. It can improve Arbuscular mycorrhiza by providing potassium to plant. Application of seaweed extract to soil can improve the availability of nutrients like calcium, nitrogen, phosphorus, potassium, and magnesium. Moreover, foliar spray of seaweed extract in rice crop increases crop growth, yield, nutrient uptake, water uptake, increases photosynthesis, and stomatal conductance. So, seaweed extract incorporation in rice cultivation could be a better approach to gain long-term sustainable production.

COMPLEX RESEARCH EXPEDITION “CRILLON 2023”: FIRST FINDINGS AND PRELIMINARY RESULTS

In August 2023, a comprehensive expedition “Crillon 2023” was performed, covering both terrestrial and marine biotopes in the southeastern part of the Crillon Peninsula (Sakhalin Island, Russia). A group of specialists carried out field work in ichthyology, invertebrate zoology, entomology, botany, lichenology, bryology, mycology, parasitology, microbiology and marine biology. In the scarcely studied territory of the southeastern part of the peninsula, a notable amount of data on species diversity was collected, including more than 200 species of plants, 101 species of lichens, 74 species of mosses, 117 species of basidial macromycetes were recorded. Marine coastal communities of the littoral and sublittoral zones were studied, and diving methods were exploited. As many as 119 species of invertebrates and 20 species of seaweed have been recorded. Information was collected on 20 species of fish, including data on helminth infestation. Parasitological studies included the search for microsporidia in all available animal hosts, as well as the search for root crayfish - parasites of arthropods. Among the animals and plants found, there are rare and endangered species included in the regional and federal Red Books, as well as those previously not recorded for Sakhalin. The preliminary results obtained indicate great potential for further study of the eastern part of the peninsula from the standpoint of biological sciences, as well as the prospects for establishment a biological station in this area for long-term research and development.

Methane gas production and phenolic compound of two species in tropical brown seaweeds

Abstract A study has indicated that the metabolites found in seaweed can lower methane emissions from ruminants, especially the phenolic compound. Indonesia is a tropical nation where seaweed variety is abundant, but it has not been widely reported to be used to reduce ruminant methane emissions. The research aims to measure the methane gas production and phenolic compound of two species in tropical brown seaweeds (Laminaria Sp. and Padina australis) from Tuban, East Java, in Kelapa Beach, Indonesia. The treatments were completely randomized with four replications and t test for the differences among treatment means. After a 24-hour incubation period, 10 mL samples used for the analysis of methane gas production were taken from the aliquot, preserved in a vacuum tube, and measured using gas chromatography (GC). The phenolic compound analysis included phenol, tannin, and flavonoid with a spectrophotometer according to Makkar (2003) and Arvouet-Grand et al. (1994) method. The result showed that Padina australis (2.47 mL and 13.00 mL/g DM) is lower in methane than Laminaria sp. (3.41 mL and 18.41 mL/g DM). Meanwhile, Padina australis is higher in flavonoid, phenol, and tannin (3.99, 0.88, 0.87 mg/g DM respectively) than Laminaria sp. (2.73, 0.63, 0.61 mg/g DM respectively). It was concluded that from two species of tropical brown seaweed, Padina australis had more potential to reduce methane emission than Laminaria sp. due to higher phenolic compounds (flavonoid, phenol, and tannin).

Rapid and portable microfluidic chip-based qPCR for quality assurance of commercial seaweeds (lavers) in the supply chain

Lavers, an important type of seaweed rich in health-promoting substances, have seen a surge in global demand. However, their similar morphological characteristics among different species make them vulnerable to food fraud. To address this issue and ensure quality assurance, we developed a portable microfluidic quantitative polymerase chain reaction (qPCR) method to monitor six laver species, comparing its effectiveness with conventional qPCR. Our portable microfluidic qPCR system used a plate-shaped heat block for rapid heat transfer, combined with a microfluidic-based biochip for quick detection. The primers were specifically designed to target the chloroplast genes rbcL and rbcS. Specificity using 17 seaweed species showed no cross-reactivity, and the sensitivity of the assay was 1 × 10−4 ng. Furthermore, we enhanced the portable microfluidic qPCR for field applications by integrating it with a simple DNA extraction method. To validate the on-site rapid identification of laver species, we evaluated 79 laver samples collected from fish farms in Korea and commercially available laver products. We discovered instances where products were adulterated with cheaper species or replaced with others that resemble them. This method proves to be rapid, sensitive, reliable, and applicable for effectively managing and monitoring lavers in the supply chain.

Insights into the structuring ability of two brown seaweeds (Laminaria digitata and Saccharina latissima) for applications as natural texturisers

Seaweeds represent a potential source of new food products with enhanced sustainability. However, in order to use seaweeds as ingredients more knowledge is needed regarding the impact of processing on their structuring ability and functionality. We report on the structure and rheology of aqueous dispersions of two species of brown seaweed, namely: Laminaria digitata and Saccharina latissima, prepared by different food processing techniques. High pressure homogenisation disrupted seaweed cell walls, leading to stable weak gels characterised by smaller particle size compared to untreated samples. Thermal treatment (70 °C 1 h), applied prior or during shear treatment, did not impact the particle size, however, it led to serum phases with higher viscosities. This was related to an increased solubilisation of polysaccharides from the cell walls into the serum, as reflected by chemical analysis and small angle X-ray scattering (SAXS). Furthermore, although in terms of rheological behaviour and particle size, both species showed similar response to food processing conditions, the cell wall nanostructure of L. digitata was modified to a larger extent compared to S. latissima, which was linked to a higher solubilisation of polysaccharides. These insights regarding functionalisation of brown seaweed dispersions provide the scientific knowledge to use whole seaweed as natural structurants for future food and other technological applications.

Identification of orange color-related gene, PhcpcC, in Pyropia haitanensis

Pigmentation-related mutations can be utilized to distinguish between differentially colored sectors of chimeric thalli, thereby facilitating the efficient breeding of economically valuable Pyropia/Porphyra seaweed species. However, the specific trait loci and alleles responsible for Pyropia/Porphyra coloration have yet to be identified, which limits the applicability of coloration mutants for breeding and genetic analyses. In this study, to preserve the genetic integrity of the population, only four-colored thalli were considered when constructing the doubled haploid (DH) Pyropia haitanensis population, which consisted of 480 homozygous offspring lines (representing the largest DH Pyropia/Porphyra population). The offspring lines in the DH population exhibited both wild-type colored and orange sectors, with a segregation ratio of approximately 1:1, indicating that the orange coloration was controlled by a single nuclear gene. Through BSA-seq analysis (99% confidence interval), a candidate region of 0.5 Mb was identified in the P. haitanensis genome. Additionally, a non-synonymous SNP [A/G] was detected at base-pair position 481 in the coding region of PhcpcC, which encodes a phycocyanin-associated rod linker protein. This SNP locus was verified in both DH and natural populations, with the wild-type colored lines having an A base and the orange lines having a G base at this locus. Therefore, PhcpcC may be the gene associated with the orange coloration of P. haitanensis. The molecular marker developed in this study can be employed to exploit pigmentation mutants for breeding and genetic analyses of Pyropia/Porphyra species.

Current biodiversity status, distribution, and prospects of seaweed in Indonesia: A systematic review

Seaweeds are a valuable component of marine biodiversity that play multiple essential roles in Indonesia's coastal ecology and economy. This systematic review (1993–2023) aimed to provide an updated overview of seaweed distribution, biodiversity, cultivation, and industry in Indonesia. The literature search derived from major databases, Scopus, Web of Science (WoS) and ResearchGate (RG), and Google Scholar (GS) retrieved 794 studies, after removing 80 duplicates, identified 646 studies passed title and abstract screening that satisfied all criteria: Indonesia, seaweed, seaweed biodiversity and composition, which consisted of 80 exclusion studies. Full text screening decided 194 studies were selected based on the specific inclusion criteria (at least two criteria passed: seaweed distribution site, species, cultivation, and habitat). After additional filtering, 137 studies were included for extraction and analysis. We found that Indonesia is rich in seaweed biodiversity, with at least 325 identified species consisting of 103 Chlorophyceae (green algae), 167 Rhodophyceae (red algae), and 55 Phaeophyceae (brown algae), respectively. Seaweed distribution and abundance in Indonesia are influenced by environmental factors, including nutrients, grazing, competition, physical tolerance, light intensity, and degree of water circulation. Seaweed species are predominantly found in mangrove forests and coral reefs on the islands of Sumatra, Java, Kalimantan, and Sulawesi. This review provides an up-to-date and comprehensive overview of the distribution and biodiversity of seaweeds in Indonesia, highlighting the ecological, economic, and cultivation of marine resources. In addition, we identify knowledge gaps and areas for further research, which can inform sustainable seaweed management and utilization in Indonesia. This review also emphasizes the significance of this marine resource to Indonesia's environment and economy.

Nutritional composition and phenolic contents of Gracilariopsis longissima, Padina tetrastromatica and Ulva intestinalis from the Bay of Bengal, Bangladesh coast

Seaweeds have become the focus of experts in recent years due to their biological characteristics and the variety of uses they have for both humans and animals. Biochemical composition, amino acids, fatty acids, and phenolic components were analyzed to explore the nutritive value of Gracilariopsis longissima, Padina tetrastromatica, and Ulva intestinalis from the Bay of Bengal, Bangladesh coast. Proximate composition and mineral content were determined according to the AOAC method. The high-performance liquid chromatography amino acid analysis system was used for the amino acid analysis and the fatty acid profile of the extracted oils was assessed as their methyl esters. The Folin–Ciocalteu technique was used to estimate the phenolic content and the aluminum chloride colorimetric technique was used to calculate the total flavonoid content. The three different species of seaweed had significantly different proximate compositions (P < 0.05), with G. longissima having the highest protein content. Except for sulfur, the mineral contents were likewise considerably higher (P < 0.05) in G. longissima. Although the amounts of the essential amino acids were greater than 50 % of the total amino acids in the three studied seaweed species, the total amino acid composition of these three species differed significantly (P < 0.05). The findings indicated that lipid levels were low in all the assessed species, but unsaturated fatty acid levels were high, with G. longissima exhibiting the highest amounts. The results showed that, compared to the other species, G. longissima had a substantially higher (P < 0.05) level of total phenolic and flavonoid content. The three studied seaweed appear to be excellent for nutrition based on their overall nutritional profiles. However, due to high protein, unsaturated fatty acid, essential amino acid, and total phenolic and flavonoid content, G. longissima is the most promising seaweed that will be helpful for pharmaceutical and multifunctional food applications.

Acid preservation of the brown seaweed Saccharina latissima for food applications

Acidification of the brown seaweed species Saccharina latissima using lactic or citric acid was investigated as a preservation method to increase the shelf life prior to further processing for use in food applications. Cut seaweed biomass was mixed with seawater or acid solution prepared using seawater and stored at ambient temperature for a period of up to 56 days. The samples were assessed through compositional analysis, recording of biomass loss and calculation of compound retentions. In addition, the sensory properties of selected samples were assessed through descriptive analysis. Acid addition resulted in a drop in pH to the range 3.6 to 4.1 for all treatments where the pH remained stable throughout the storage period. For the sample preserved in seawater only, pH dropped from 7.3 to 4.3 during the storage period due to production of lactic acid by naturally occurring bacteria. All treatments resulted in biomass and loss of minerals (mainly K) and carbohydrates, which correlated positively with acid concentration with the exception for mannitol where the highest loss was found in the seawater-preserved sample. Samples with low concentration of lactic or citric acid had the lowest total mass loss and highest retention of dry matter. Increasing concentrations of lactic acid led to lower total remaining dry matter and lower compound retention. Finally, the sensory evaluation showed that the intensity of sour taste significantly differed between treatments which were otherwise characterized by high saltiness. Higher acid dose resulted in a more sour taste and lactic acid was perceived as less sour than citric acid. In addition, lower sourness correlated with a more intense saltiness. The sensory profiles were not significantly affected by storage time.

Spatiotemporal analysis in brown seaweed diversity and abundance at selected coastal locations on the Southern coast of Tamil Nadu, India: A way forward for conservation and sustainable utilization

Tamil Nadu and its southern coast are well-known for seaweed diversity and abundant resources in India. Brown seaweeds are primary habitat producers in reef environments. The objective of this study was to assess the spatiotemporal variation in diversity and abundance of brown seaweed species along the intertidal region at selected coastal locations on the southern coast of Tamil Nadu, India. The sampling was performed monthly at six coastal locations, namely Hare Island (HI), Tuticorin Harbour (TH), Chinna Muttom (CM), Arockiapuram (AP), Vedhalai (VD), and Mandapam (MP), along the intertidal region during low tides between January 2021 and December 2021. A total of 36 brown seaweed species were identified at six locations, namely Sargassum (9 species), followed by Padina (5 species), Turbinaria (3 species), Dictyota (3 species) and 16 species each of others. In the context of different locations, the highest species diversity was observed at HI (35) and the lowest at CM (21) during the study period. The highest abundance was recorded at CM (19.80 kg wt m−2), while the lowest was reported at AP (9.51 kg wt m−2). Sargassum and Turbinaria exhibited the highest prevalence across all the locations. Among different seasons, the maximum species diversity was recorded during PoMoN (26), whereas the minimum species diversity was recorded during PrMoN (11). Similarly, the highest abundance was seen during PoMoN, whereas the lowest abundance was reported during PrMoN. These findings offer crucial foundational data for the preservation and exploitation of brown seaweeds.

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.

Methylation-GC-MS/FID-Based Glycosidic Linkage Analysis of Unfractionated Polysaccharides in Red Seaweeds.

Glycosidic linkage analysis was conducted on the unfractionated polysaccharides in alcohol-insoluble residues (AIRs) prepared from six red seaweeds (Gracilariopsis sp., Prionitis sp., Mastocarpus papillatus, Callophyllis sp., Mazzaella splendens, and Palmaria palmata) using GC-MS/FID analysis of partially methylated alditol acetates (PMAAs). The cell walls of P. palmata primarily contained mixed-linkage xylans and small amounts of sulfated galactans and cellulose. In contrast, the unfractionated polysaccharides of the other five species were rich in galactans displaying diverse 3,6-anhydro-galactose and galactose linkages with varied sulfation patterns. Different levels of cellulose were also observed. This glycosidic linkage method offers advantages for cellulose analysis over traditional monosaccharide analysis that is known for underrepresenting glucose in crystalline cellulose. Relative linkage compositions calculated from GC-MS and GC-FID measurements showed that anhydro sugar linkages generated more responses in the latter detection method. This improved linkage workflow presents a useful tool for studying polysaccharide structural variations across red seaweed species. Furthermore, for the first time, relative linkage compositions from GC-MS and GC-FID measurements, along with normalized FID and total ion current (TIC) chromatograms without peak assignments, were analyzed using principal component analysis (PCA) as a proof-of-concept demonstration of the technique's potential to differentiate various red seaweed species.

Electrical bioimpedance spectroscopy as a non-invasive monitoring tool of physiological states of macroalgae tissues: example on the impact of electroporation on 8 different seaweed species

In this study, we evaluated Electrical Impedance Spectroscopy (EIS) as a monitoring tool of the physiological state of Bryopsis, Cystoseira, Stypopodium, Cladophora, Taonia, Padina, Ulva and Sargassum tissues. We analyzed the electrical response differences in the EIS between species and in the same seaweed tissue before and after electroporation. Electroporation using high voltage pulsed electric field (PEF) treatment was used as a model for cell disruption affecting the tissue physiology without being noticeable to the naked-eye. Significant differences in all the seaweeds were observed before and after electroporation. We found that seaweed species with smaller and rounder cells have a clearer dispersion profile (around a frequency of 10–100 kHz) compared to the dispersion profile of seaweed with larger cells with unround form. Those results suggest that EIS could be used as a fast non-invasive monitoring technique of the changes in the physiology of seaweeds.

Gathering and Cooking Seaweeds in Contemporary Ireland: Beyond Plant Foraging and Trendy Gastronomies

Seaweed has historically been essential for coastal communities worldwide. Following a period of decline in the last century, Ireland has seen a recent resurgence in the appreciation and use of seaweed. This research explores the evolution in seaweed foraging practices, with a specific focus on gastronomical uses in two Irish regions: the southwest and the west and midwest. It examines the diversity of seaweed and its present and past uses, comparing abandonment, continuation and revitalisation trajectories. Qualitative data were gathered through semi-structured interviews with 27 individuals who forage seaweed for commercial or personal use. We identified 22 seaweed species across the study areas, predominantly from the Fucaceae, Laminariaceae and Ulvaceae families. There was a fair divergence between the seaweed species used in the two study areas (16 seaweed species in the southwest region and 17 seaweed species in the west and midwest region), with 11 species mentioned in both areas. Different trajectories of resurgence were identified. In the west and midwest region, the revitalisation of local ecological and gastronomic knowledge related to seaweeds seems to be deeply entrenched in the territory’s historical legacy, showing a sort of continuation with the past and having followed a more commercially oriented path. Conversely, in the southwest region, the revival seems to be fostered by new knowledge holders with a contemporary interest in reconnecting with the marine landscape and promoting educational activities centred around seaweed. This research contributes to discussions on sustainable food systems and food heritage promotion, emphasising seaweed’s potential role in Irish coastal communities’ foodscapes.

Biochemical profiling and antioxidant activity analysis of commercially relevant seaweeds from northwest Europe.

The drive towards ensuring the sustainability of bioresources has been linked with better valorising primary materials and developing biorefinery pipelines. Seaweeds constitute valuable coastal resources with applications in the bioenergy, biofertiliser, nutrition, pharmaceutical and cosmetic sectors. Owing to the various sought-after metabolites they possess, several seaweed species are commercially exploited throughout Western Europe, including Ireland. Here, four commercially relevant brown (Fucus serratus and Fucus vesiculosus) and red (Chondrus crispus and Mastocarpus stellatus) seaweed species were sampled during a spring tide in July 2021 on moderately exposed shores across three coastal regions in the west of Ireland. Significant regional differences were identified when specimens were analysed for carbohydrates (max. 80.3 μg glucose eq mg-1 DW), proteins (max. 431.3 μg BSA eq. mg-1 DW), lipids (max. 158.6 mg g-1 DW), pigment signature and antioxidant potential. Protein content for F. serratus recorded a twofold difference between northern and southern specimens. The antioxidant potential of F. vesiculosus and M. stellatus returned greater activity compared to F. serratus and C. crispus, respectively. Multivariate analysis showed a clear latitudinal pattern across the three western coastal regions (north, west and south) for both F. vesiculosus and F. serratus. F. vesiculosus thalli from the northwest were richer in pigment content while the F. serratus thalli from the northwest were richer in antioxidants. Such biogeographic patterns in the biochemical make-up of seaweeds need consideration for the development of regional integrated aquaculture systems and the optimisation of the biomass content for targeted downstream applications. © 2024 Society of Chemical Industry.

Characterization of low molecular weight sulfur species in seaweed from the Antarctic continent.

Antarctic seaweeds are vital components of polar marine ecosystems, playing a crucial role in nutrient cycling and supporting diverse life forms. The sulfur content in these organisms is particularly interesting due to its implication in biogeochemical processes and potential impacts on local and global environmental systems. In this study, we present a comprehensive characterization of seaweed collected in the Antarctic in terms of their total sulfur content and its distribution among different classes of species, including thiols, using various methods and high-sensitivity techniques. The data presented in this paper are unprecedented in the scientific literature. These methods allowed for the determination of total sulfur content and the distribution of sulfur compounds in different fractions, such as water-soluble and proteins, as well as the speciation of sulfur compounds in these fractions, providing valuable insights into the chemical composition of these unique marine organisms. Our results revealed that the total sulfur concentration in Antarctic seaweeds varied widely across different species, ranging from 5.5 to 56gkg-1 dry weight. Furthermore, our investigation into the sulfur speciation revealed the presence of various sulfur compounds, including sulfate, and some thiols, which were quantified in all ten seaweed species evaluated. The concentration of these individual sulfur species also displayed considerable variability among the studied seaweeds. This study provides the first in-depth examination of total sulfur content and sulfur speciation in brown and red Antarctic seaweeds.

Seaweed and the applicability of freeze drying techniques

Seaweed, often considered an overlooked resource, are marine algae with many applications in various industries. The many species of seaweed possess a range of nutritional values, environmental benefits, and their versatility make them an attractive subject of research and development. One promising method for preserving and utilising seaweed effectively is freeze drying. This review explores the world of seaweed, its properties, applications, and the potential of freeze-drying techniques in harnessing the above benefits. The review examines the freeze-drying process and discusses its applicability and advantages in preserving seaweed as a sustainable resource. The discussion also includes the diverse uses of seaweed, from culinary applications to pharmaceuticals and beyond, highlighting the potential of freeze-drying to unlock seaweed’s full potential

Effects of Different Solvents on the Antioxidant Activity of Several Seaweed Species from Semporna, Sabah, Malaysia

Sabah is the main seaweed producer in Malaysia especially red seaweeds which are commercially cultivated for the production of food gum known as carrageenan. Seaweeds are also high in phytochemical such as antioxidant compounds. Three seaweeds species from the Semporna Seawater, Sabah, namely Kappaphycus alvarezii, Caulerpa lentillifera and Sargassum polycystum were chosen for this study for the analysis of their antioxidant activities. K. alvarezii species is commercially cultivated whereas the other two (C. lentillifera and S. polycystum) are wild species. All seaweeds species underwent drying process in a cabinet dryer prior to the analyses. Six types of solvents which were water, ethanol, methanol, chloroform, ethyl acetate and hexane were used for the extraction process. Every concentrated, extracted solutions were then measured for their antioxidant activities based on total phenolic content (TPC), diphenylpicrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) and β-carotene bleaching assay. Results showed that TPC of S. polycystum was significantly higher (p&lt;0.05) than K. alvarezii but not significantly different (P&gt;0.05) from C. lentillifera. Even though the extraction yield of water was the highest, but the greatest antioxidant activity values were seen in methanolic extraction in comparison to the other solvents in TPC, DPPH and FRAP. This indicated that most of the antioxidant compounds in all the three seaweed samples are polar. However, high antioxidant activity in terms of β-carotene bleaching assay were seen in other solvent extractions, which were chloroform, hexane and ethyl acetate. This indicated that seaweed also contain non-polar antioxidant compounds such as β-carotene. Overall, the best extraction method of antioxidant compounds in seaweed samples was using methanol as the extractant.