Search Results (57)

To address the increasing global demand for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), novel and sustainable sources are required. Seaweeds have been identified as promising alternative sources of these fatty acids (FAs). This study evaluated the FA profiles of dry, commercially available seaweeds in the United Kingdom, including Porphyra spp., Palmaria palmata, Himanthalia elongata, Laminaria digitata, Saccharina japonica, Undaria pinnatifida, Sargassum fusiforme and Fucus vesiculosus. FA identification was performed by gas chromatography. The highest content of polyunsaturated FAs (PUFAs) was observed in U. pinnatifida, accounting for 67.68% of the total FAs (TFAs). EPA represented 33.34% of TFA content in Rhodophyta and 7.13% in Ochrophyta. EPA was the dominant FA in Porphyra spp., comprising 38.91% of TFAs (1064.40 mg/100 g dry weight). A higher content of EPA was also found in P. palmata (32.18%), L. digitata (13.76%), and U. pinnatifida (13.00%). DHA content was consistently lower than that of EPA, with the highest proportion observed in P. palmata (0.27% of TFAs). U. pinnatifida, P. palmata and Porphyra spp. appear to be the most promising seaweed species for providing n-3 long-chain PUFAs in human diets. Full article

This study investigated the α-glucosidase inhibitory potential of enzymatic/alkaline treatments from Palmaria palmata using different proteases and pairwise combinations thereof. Treatments prepared with Alcalase^®, Flavourzyme^®, and Formea^® Prime, alone or in combination, were evaluated for dose-dependent inhibitory activity. Alcalase^®-derived treatments exhibited the highest α-glucosidase inhibition, achieving an IC₅₀ of 2.48 mg·mL⁻¹, outperforming other treatments and combinations. Membrane fractionation of the Alcalase^®-derived treatment into >5 kDa, 3–5 kDa, 1–3 kDa, and <1 kDa fractions revealed a size-dependent trend, with the <1 kDa fraction showing the strongest inhibition (IC₅₀ of 1.94 mg·mL⁻¹). Three peptides, RADIPFRRA, DGIAEAWLG, and FWSQIFGVAF, from the <1 kDa fraction were identified as potential α-glucosidase inhibitors using the BIOPEP-UWM database and were further selected based on a Peptide Ranker score above 0.6 for in silico docking analyses. Docking revealed distinct binding modes: RADIPFRRA and DGIAEAWLG occupied the catalytic cleft, interacting with key residues (Asp518, Asp616, Trp481, Trp613) consistent with competitive inhibition, whereas FWSQIFGVAF bound to a peripheral site, suggesting potential allosteric modulation. Physicochemical analysis further highlighted differences in charge and isoelectric point correlating with their binding behavior. Together, these findings demonstrate that low-molecular-weight peptides derived from P. palmata proteins, particularly those generated by Alcalase^®, possess significant α-glucosidase inhibitory activity, and provide structural insights for the rational design of peptide-based modulators of carbohydrate metabolism. Full article

Docosahexaenoic acid (DHA), an omega-3 fatty acid essential for human health, is highly prone to oxidation in nanoemulsions due to their large interfacial area and presence of transition metal ions. This study investigated macroalgal chelators for stabilizing DHA-rich nanoemulsions. Sequential enzymatic–alkaline extraction using Alcalase^® produced an extract with the strongest Fe²⁺-chelating activity (IC₅₀ = 1.22 mg/mL), protein content of 10.11 ± 0.15%, and total phenolics ≈ 17 µg GAE/mL. This extract was incorporated into nanoemulsions (5 wt% DHA oil, 1 wt% Tween^® 20) at 0.61, 1.22, and 2.44 mg/mL and compared with controls containing EDTA (0.025 mg/mL) or no antioxidant. Droplet size remained stable (D_3,2 ≈ 77–80 nm; D_4,3 ≈ 199–215 nm) and zeta potential averaged −17 to −19 mV, confirming physical stability. Confocal microscopy revealed concentration-dependent interfacial adsorption of extract components. During iron-accelerated storage, extract-treated nanoemulsions slowed hydroperoxide formation and delayed tocopherol depletion compared to the control, while reducing volatile oxidation markers such as 1-penten-3-ol by up to 40%. However, EDTA consistently provided superior protection against oxidation. These findings highlight the potential of macroalgal extracts as clean-label, natural chelators for mitigating metal-driven oxidation in DHA nanoemulsions, though synthetic chelators remain more effective under severe prooxidant conditions. Full article

Macroalgae are increasingly recognized as a valuable source of nutrients and bioactive compounds for animal nutrition, including for aquatic species. However, the complex structure of the macroalgal cell wall limits the accessibility of intracellular components, restricting their use in feeds. To overcome this limitation, macroalgal hydrolysis using various technological treatments has been tested, often employing a low solid-to-water ratio, which complicates downstream processing due to phase separation. In contrast, high-solids loading hydrolysis has the advantage of producing a single and consolidated fraction, simplifying subsequent processing and application. The present study assessed the effectiveness of high-solids loading water or alkaline (0.5 and 1N NaOH) autoclaving for 30 or 60 min, applied alone or followed by sequential enzymatic hydrolysis, using a xylanase-rich enzymatic complex aimed at promoting cell wall disruption and increasing the extractability of intracellular components in the red macroalga Palmaria palmata with minimal free water. The 1N NaOH treatment for 30 min decreased neutral and acid detergent fiber while increasing Folin–Ciocalteu total phenolic content (GAE) (expressed as gallic acid equivalent) and the water-soluble protein fraction and decreased crude protein, indicating enhanced extractability of these components. Microscopic examination showed relatively mild structural changes on the surface of P. palmata after high-solids loading alkaline (1N NaOH) autoclaving for 30 min. Following alkaline or water treatment, the enzymatic complex hydrolysis further increased the Folin–Ciocalteu total phenolic content (GAE), with minimal effects on NDF, ADF, or crude protein. Overall, these results showed that high-solids loading alkaline autoclaving, with or without subsequent enzymatic hydrolysis, effectively disrupts P. palmata cell walls and induces substantial modifications while simplifying processing by avoiding phase separation. Full article

This study investigates the anti-obesity and antidiabetic potential of P. palmata extracts produced through sequential enzymatic and alkaline treatments. Among the treatment groups, the extract treated solely with Alcalase^® (Alc) demonstrated the highest protein content (10.11 ± 0.15%) and degree of hydrolysis (30.36 ± 0.77%), significantly outperforming other treatments (p < 0.05). The Alc extract also exhibited superior inhibitory activity against porcine pancreatic lipase and α-amylase, achieving the lowest IC₅₀ for lipase (2.29 ± 0.87 mg.mL⁻¹) and showing significant enzyme inhibition across all tested concentrations (p < 0.05). Ultrafiltration of the Alc extract revealed that peptide fractions < 1 kDa and 1–3 kDa were most effective in enzyme inhibition, with IC₅₀ values of 3.25–3.55 mg.mL⁻¹ for both lipase and α-amylase. Peptides were identified via LC-MS/MS analysis and database searching using SequestHT, resulting in 536 sequences, of which bioinformatic screening yielded 51 non-toxic, non-allergenic candidates (PeptideRanker score > 0.6); four of these contained known inhibitory motifs for lipase and α-amylase. Molecular docking confirmed strong binding affinities between these peptides and their respective enzymes, supporting their potential as natural enzyme inhibitors. These findings indicate the functional food potential of Alcalase^®-derived P. palmata peptides for managing obesity and type 2 diabetes. Full article

In recent years, insects have emerged as a nutritious and eco-sustainable alternative food source, with the house cricket (Acheta domesticus, AD) recently authorized by the European Commission as a novel food. However, the presence of harmful substances in insects poses potential health risks. This study investigated the content of potentially toxic elements (PTEs) such as cadmium (Cd), arsenic (As), lead (Pb), mercury (Hg), nickel (Ni), chromium (Cr), and aluminium (Al) in Acheta domesticus fed diets enriched with graded levels of the red seaweed Palmaria palmata or the brown seaweed Ascophyllum nodosum in two feeding trials. Chemical analyses were carried out by graphite furnace atomic absorption spectrophotometry for all elements except Hg, which was analyzed by thermal decomposition amalgamation atomic absorption spectrometry. The results showed that PTE content in the diets was below the legal limits for feed. The PTEs in AD ranged (mg kg⁻¹ dry matter) as follows: Cd (0.069 ± 0.005–0.127 ± 0.002), As (0.08 ± 0.01–0.36 ± 0.03), Pb (0.05 ± 0.01–0.12 ± 0.01), Hg (0.0065 ± 0.0002–0.0141 ± 0.0010), Ni (0.64 ± 0.06–1.20 ± 0.10), Cr (0.16 ± 0.02–0.58 ± 0.01), and Al (17 ± 2–61 ± 1). AD bioaccumulated As and Hg; however, the PTE levels remained below European Union food safety limits. The absence of non-carcinogenic risk for consumers suggests that AD fed seaweed-enriched diets are a safe, healthy, and low-chemical risk food for humans. Full article

Anthropogenic warming of the world’s oceans is not just an environmental crisis, but may result in a significant threat to human health. The combination of a warming ocean and increased human activity in coastal waters sets the stage for increased pathogenic Vibrio–human interaction. Warming patterns due to climate change have already been related to the emergence of Vibrio outbreaks in temperate and cold regions. Seafoods, including seaweeds, are uniquely poised to contribute to global food and nutrition security. In recent years there has been a resurgence of interest in seaweeds due to their many uses, high nutritional value, and ability to provide ecosystem services such as habitat provision, carbon and nutrient uptake, and coastal protection. However, some seaweed species can be a reservoir for harbouring pathogenic Vibrio, and illnesses like gastroenteritis have recently been associated with foods prepared with seaweeds. In this study, we investigated the impact of elevated water temperatures on abundances of the major human pathogens Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio vulnificus/cholerae on seaweed and in coastal waters. Three seaweed species, Fucus serratus, Palmaria palmata, and Ulva spp., were exposed to temperature treatments (16 °C and 20 °C) to assess the effects of mean-temperature rise on Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio vulnificus/cholerae colonisation. Colony-forming units (CFUs) on seaweed surfaces and in surrounding water were counted. F. serratus and P. palmata showed significantly higher Vibrio abundances at higher temperatures compared with Ulva spp.; however, temperature did not significantly affect abundances of tested Vibrio species in surrounding waters. These results indicate that certain seaweed species may serve as major hotspots for human pathogenic bacteria in warmer conditions, with implications for human health. Full article

The complex plant cell wall heteropolysaccharide xylan, and its breakdown products xylo-oligosaccharides and xylose, are value-added compounds with a plethora of potential applications in diverse areas. They are nonetheless currently poorly exploited, with a major bottleneck being the unavailability of efficient, low-cost, high-yield production processes. The major objective of the present study is to identify and characterise a high-yield process for the preparation of highly pure xylan/XOS products from the macroalga Palmaria palmata. Currently, most xylan is extracted from land-sourced lignocellulosic feedstocks, but we take advantage of the high xylan content, xylan aqueous solubility, lignin-free nature, weakly linked cell wall matrix, and sustainability of the macroalga to identify a simple, sustainable, high-yield, novel-xylan-structure extraction process. This is composed of five steps: alga oven drying, milling, aqueous extraction, centrifugation, and dialysis, and we show that the alga preservation step plays a critical role in component extractability, with oven drying at high temperatures, ~100 °C, enhancing the subsequent aqueous extraction process, and providing for xylan yields as high as 80% of a highly pure (~90%) xylan product. The process developed herein and the insights gained will promote a greater availability of these bioactive compounds and open up their application potential. Full article

The main objective of this study was the development of two semi-hard goat cheeses supplemented with Palmaria palmata and Ulva sp. with the aim of developing innovative food products, increasing the concentration of nutrients in these cheeses and familiarizing consumers with seaweed-containing foods. The impact of seaweed addition was evaluated through physicochemical, microbiological, and organoleptic properties of the semi-hard goat cheeses. Carbohydrate content was relatively low, whereas the total lipid content was relatively high (particularly in semi-hard goat cheese supplemented with seaweeds). Crude protein content presented higher values in semi-hard goat cheese supplemented with Ulva sp. The semi-hard goat cheese supplemented with Ulva sp. shows increased levels of Ca, Fe, Mn, and Zn. Instrumental color and the textural parameters of semi-hard goat’s cheese varied significantly with seaweed addition. Most of the microbiological load complies with the Portuguese (INSA) and the United Kingdom’s (HPA) guidelines for assessing the microbiological safety of ready-to-eat foods placed on the market. Additionally, the Flash Profile scores of semi-hard goat cheeses supplemented with seaweeds highlighted aroma and flavor complexity. Overall, this study confirms the potential of using seaweeds as a viable alternative to produce semi-hard goat cheeses with less pungency or goat milk flavor, making this product more pleasant and appealing to consumers sensitive to these sensory characteristics. Full article

The extraction of bioactive compounds from marine natural products has gained increasing attention due to their diverse applications, such as in pharmaceuticals, nutraceuticals, and cosmetics. Yet, low extraction yields and toxicity associated with common solvents are a major bottleneck. Deep eutectic solvents (DESs) and natural deep eutectic solvents (NADESs) have emerged as promising green alternatives to conventional organic solvents, offering advantages such as biodegradability, greater environmental and economic sustainability, low toxicity, and enhanced extraction selectivity. This review provides a comprehensive analysis of the principles, physicochemical properties, and applications of DESs/NADESs to obtain bioactive compounds from marine organisms. Among the most recent works, it is possible to verify the success of NADESs to extract carrageenan from the seaweed Kappaphycus alvarezii; pigments from Palmaria palmata; and polyphenols and proteins from different brown seaweeds. NADESs have also shown high potential to extract other valuable compounds from marine by-products, such as chitin from crabs and shrimp shells, and also lipids and proteins from different fish species and protein rich extracts from tilapia viscera. The challenges for DESs/NADESs use at industrial scale are also discussed, and success cases are revealed, highlighting their potential as game changers for extracting bioactive compounds from marine organisms and driving the development of innovative biotechnological products. Full article

Hypertension, type 2 diabetes (T2D), and obesity raise an individual’s risk of suffering from diseases associated with metabolic syndrome (MS). In humans, enzymes that play a role in the prevention and development of MS include angiotensin converting enzyme (ACE-1) associated with hypertension, α-amylase associated with T2D, and lipase linked to the development of obesity. Seaweeds are a rich source of bioactives consisting of proteins/peptides, polysaccharides, and lipids. This study examined the potential of seaweed-derived bioactives from Alaria esculenta, Ulva lactuca, and Palmaria palmata as inhibitors of ACE-1, α-amylase, and lipase. In vitro enzyme inhibitory assays were used to quantify the bioactivity of the seaweed extracts and compare their half-maximal inhibitory (IC₅₀) values to recognised positive control enzyme inhibitory drugs captopril© (an ACE-1 inhibitor), acarbose (an α-amylase inhibitor), and orlistat (a lipase inhibitor). Three seaweed extracts displayed enzyme inhibitory activities equal to, or more effective than, the reference positive control drugs. These were P. palmata peptides (ACE-1 IC₅₀ 94.29 ± 3.07 µg/mL, vs. captopril© 91.83 ± 2.68 µg/mL); A. esculenta polyphenol extract (α-amylase IC₅₀ 147.04 ± 9.72 µg/mL vs. acarbose 185.67 ± 12.48 µg/mL, and lipase IC₅₀ 106.21 ± 6.53 µg/mL vs. orlistat 139.74 ± 9.33 µg/mL); and U. lactuca polysaccharide extract (α-amylase IC₅₀ 168.06 ± 10.53 µg/mL vs. acarbose 185.67 ± 12.48 µg/mL). Proximate analysis also revealed that all three seaweeds were a good source of protein, fibre, and polyunsaturated essential fatty acids (PUFAs). These findings highlight the potential of these seaweeds in the management of diseases associated with MS and as foods. Full article

This research examined antioxidant and anti-obesity effects of Palmaria palmata extracts obtained through acidic or alkaline treatments and subsequent pH adjustments. After two rounds of acidic or alkaline extraction, the extracts were separated from biomass and adjusted to different pH values: for acidic extracts, pH 3 (no adjustment), pH 6, pH 9, and pH 12; for alkaline extracts, pH 12 (no adjustment), pH 9, pH 6, and pH 3. The findings revealed that extraction medium as well as subsequent pH adjustments significantly influenced composition of the extracts in terms of protein content and recovery, amino acids, and phenolic compounds (p < 0.05). Acidic conditions produced extracts with potent radical scavenging, especially at pH 6 (IC₅₀ = 0.30 ± 0.04 mg.mL⁻¹), while alkaline conditions favored metal chelating, with the highest Fe²⁺ chelation at pH 12 (IC₅₀ = 0.65 ± 0.03 mg.mL⁻¹). Moreover, extracts showed inhibitory activities against porcine pancreatic lipase and α-amylase, with the acidic extract at pH 9 showing the best anti-obesity properties (IC₅₀ = 5.38 ± 0.34 mg.mL⁻¹ for lipase and IC₅₀ = 5.79 ± 0.30 mg.mL⁻¹ for α-amylase). However, the highest α-amylase activity was in the alkaline extract at pH 12 (IC₅₀ = 3.05 ± 0.66 mg.mL⁻¹). In conclusion, adjusting the pH of seaweed extracts notably influences their bioactive properties, likely due to changes in the reactivity and interactions of bioactive compounds such as peptides, carbohydrates, and polyphenols. Full article

This study investigates the nutritional composition and bioactive properties of Palmaria palmata (dulse), Ascophyllum nodosum (knotted wrack), and Chondrus crispus (Irish moss). Understanding the nutritional values of these seaweeds is very important due to their potential health benefits, especially their antioxidant properties and cytotoxic activities, which point to their ability to inhibit cancer cell proliferation. Comprehensive analyses were conducted to assess protein content, amino acid composition, mineral profile, fatty acids, polyphenols, total carotenoids, antioxidant activity, and cytotoxicity against cervical (HeLa), and colon (HCT-116) cell lines. P. palmata exhibited the highest protein content, while C. crispus was richest in calcium, iron, manganese, and zinc. Amino acid analysis revealed C. crispus as being particularly high in essential and non-essential amino acids, including alanine, glutamic acid, and glycine. A. nodosum and C. crispus were rich in polyunsaturated fatty acids (PUFAs), notably eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). A. nodosum showed the highest total carotenoid content. Polyphenol analysis highlighted the presence of compounds such as p-coumaric acid, gallic acid, and p-hydroxybenzoic acid across the species. Both the ethanolic and hexane A. nodosum extracts demonstrated the strongest antioxidant potential in DPPH^• and ABTS⁺ assays. The cytotoxicity evaluation revealed high anticancer activity of A. nodosum and C. crispus hexane extract against HeLa and HCT-116, though it employed cell cycle arrest and apoptosis. A. nodosum hexane extract exhibited moderate selective anticancer activity against HCT-116. These findings underscore the nutritional diversity and potential health benefits of these macroalgae (seaweed) species, suggesting their suitability as functional foods or supplements, offering diverse nutritional and therapeutic benefits. Full article

Seaweed is a great source of biologically active metabolites which could prove interesting in cosmeceutical applications. In this study, seven Icelandic seaweed species (Ascophyllum nodosum, Alaria esculenta, Laminaria hyperborea, Laminaria digitata, Saccharina latissima, Palmaria palmata, and Schizymenia jonssonii) were screened for total polyphenol content, antioxidant properties, and inhibition of skin-degrading enzymes. Antioxidant assays included DPPH (2,2-diphenyl-1-picrylhydrazyl), reducing power, and ORAC (oxygen radical absorbance capacity). In most assays, A. nodosum extracts were the most active. A. nodosum extracts also showed the strongest inhibition of the skin-degrading enzymes elastase and collagenase at low concentrations, demonstrating its skin-protective qualities. To further investigate the activity, A. nodosum was subsequently extracted with solvents with increasing polarity into seven different extracts. Compared to other extracts, the extracts obtained by extraction with acetone and methanol showed the highest activity in all assays. Extracts obtained with room-temperature water and 85 °C water also demonstrated moderate to high activities. The outcomes of this study support the potential utilization of the brown seaweed A. nodosum as a source of natural ingredients in cosmeceuticals. Full article

A biorefinery process was developed to isolate phycobiliproteins, sulfated polysaccharides, and phenolic compounds from Palmaria palmata. The extraction process was carried out in three stages using ultrasound-assisted extraction (UAE) and pressurized liquid extraction (PLE) integrated with different natural deep eutectic solvents (NaDESs). In general, PLE provided higher phycobiliprotein contents than UAE in the first step of the process. In fact, the hydrolysis product of the PLE-NaDES extracts achieved a higher antioxidant capacity than that of the UAE-NaDES extracts. Particularly, glycerol:glucose (2:1) with 50% water in combination with PLE was the most suitable NaDES to recover the highest phycobiliprotein, protein, and sulfated polysaccharide contents from Palmaria palmata in the first and second steps of the biorefinery process. Finally, a PLE-NaDES using choline chloride:glycerol (1:2) with 60% water as the NaDES was employed for the recovery of antioxidant and neuroprotective phenolic compounds from the residue of the second step, obtaining a higher total phenolic content than employing PLE with ethanol/water (70:30, v/v) as the extraction solvent. Moreover, a forced stability study revealed that the NaDESs provided a protective effect compared to the water extracts against the degradation of phycobiliproteins, preserving their color over time. This study contributes to the recovery of high-value components from an undervalued biomarine source through a sustainable biorefinery process. Full article