Carrageenan Research Articles

Carrageenan maintains the contractile phenotype of vascular smooth muscle cells by increasing macromolecular crowding in vitro

BackgroundThe contractile phenotype of vascular smooth muscle cells (VSMCs) results in good diastolic and contractile capacities, and its altered function is the main pathophysiological basis for diseases such as hypertension. VSMCs exist as a synthetic phenotype in vitro, making it challenging to maintain a contractile phenotype for research. It is widely recognized that the common medium in vitro is significantly less crowded than in the in vivo environment. Additionally, VSMCs have a heightened sense for detecting changes in medium crowding. However, it is unclear whether macromolecular crowding (MMC) helps maintain the VSMCs contractile phenotype.PurposeThis study aimed to explore the phenotypic, behavioral and gene expression changes of VSMCs after increasing the crowding degree by adding carrageenan (CR).MethodsThe degree of medium crowding was examined by a dynamic light scattering assay; VSMCs survival and activity were examined by calcein/PI cell activity and toxicity and CCK-8 assays; VSMCs phenotypes and migration were examined by WB and wound healing assays; and gene expression was examined by transcriptomic analysis and RT-qPCR.ResultsNotably, 225 μg/mL CR significantly increased the crowding degree of the medium and did not affect cell survival. Simultaneously, CR significantly promoted the contraction phenotypic marker expression in VSMCs, shortened cell length, decreased cell proliferation, and inhibited cell migration. CR significantly altered gene expression in VSMCs. Specifically, 856 genes were upregulated and 1207 genes were downregulated. These alterations primarily affect the cellular ion channel transport, microtubule movement, respiratory metabolism, amino acid transport, and extracellular matrix synthesis. The upregulated genes were primarily involved in the cytoskeleton and contraction processes of VSMCs, whereas the downregulated genes were mainly involved in extracellular matrix synthesis.ConclusionsThe in vitro study showed that VSMCs can maintain the contractile phenotype by sensing changes in the crowding of the culture environment, which can be maintained by adding CR.Graphical

Colloid‐encapsulated sugarcane polyphenols and their impact on in vitro starch digestibility: enhancing bioaccessibility and α‐amylase inhibitory effect

SummaryThis study focuses on encapsulation of sugarcane polyphenols (SPs) to assess its impact on their bioaccessibility and efficacy in inhibiting starch digestion, thereby contributing to glycaemic control strategies. The hypothesis posits that encapsulation enhances both the bioaccessibility and functional effectiveness of SPs. Carboxymethyl cellulose (CMC) and carrageenan (CAR) were employed as encapsulating agents. The methodology included an evaluation of α‐amylase inhibitory activity and the bioaccessibility of SPs across various encapsulation formulations in vitro digestion, highlighting a specific formulation that combines 0.5% CMC and 0.5% CAR to encapsulate 0.4% SPs. Findings reveal that this formulation significantly increases SPs' bioaccessibility and exhibits the highest α‐amylase inhibitory activity, suggesting its potential to support a low glycaemic index (GI) diet (GI = 54.7). It was observed that the GI is significantly inversely correlated with the bioaccessibility of total polyphenols and proanthocyanidins in SPs, while the bioaccessibility of total flavonoids in SPs showed no significant effect on pGI. Interestingly, SPs encapsulated with CMC were less effective in inhibiting starch digestibility than unencapsulated SPs, attributed to the tight binding of CMC with polyphenols, which limits their interaction with starch and α‐amylase. The study highlights the crucial influence of encapsulation materials on polyphenol functionality and emphasises the need for strategic encapsulation in modulating glycaemic responses. These findings advance the understanding of how processing technologies can optimise the health benefits of dietary bioactives, guiding future research towards functional applications and dietary interventions for glycaemic control.

Benzoylation of Iota Carrageenan: Development of a Stable, Conductive, and Hydrophobic Drug Carrier with Reduced Toxicity and Improved Gel‐Forming Ability

AbstractIota carrageenan is characterized as a hydrocolloid, with the limitations of hygroscopicity and hydrophilicity. Here, each of these factors is addressed to enhance the stability, and hydrophobicity through the protection of highly reactive primary alcohol and the formation of stable, improved hydrophobic, and conductive gel for the loading of lipophilic drugs. The functionalized polymer is evaluated through the microscopic and scanning electron microscopy (SEM) image of the compounds, which confirm the confined nature of the functionalized polymer. Moreover, the values changed from compound 1 (iota carrageenan) to compound 2 (benzoyl liked iota carrageenan) included Log P (partition coefficient) from −0.97 to 0.90, calculated partition coefficient (cLog P) from −2.50 to 0.12, and total polar surface area (TPSA) from 214.1 to 208.57, which strongly suggest the enhanced hydrophobic character of functionalized polymers. The enhancement is further concluded by the loading of the lipophilic drug inside the core of functionalized polymer‐based gel. The enhanced loading of the drug clearly shows the improved hydrophobicity (56–86%) of the gel core of the functionalized compounds. In summary, a polymer with enhanced stability, hydrophobicity, conductivity, and capacity to make a more stable gel, with enhanced drug‐loading capability of water‐insoluble drugs, will be the best way to resolve the low bioavailability issue of the water‐insoluble drug.

Construction of emulsion gel based on the interaction of anionic polysaccharide and soy protein isolate: Focusing on structural, emulsification and functional properties

In this study, the effects on the structures and emulsion gels of carrageenan (CA) and gum arabic (GA) with soybean protein isolate (SPI) were investigated. The results showed that CA and GA exposed hydrophobic groups to SPI, and formed complexes through non-covalent interactions to improve the stability of the complexes. Furthermore, the emulsion gels based on the emulsions exhibited that CA formed emulsion-filled gels with higher elasticity, stronger gel strength, and thermal reversibility, whereas GA formed emulsion-aggregated gels with higher viscosity, and a weak-gel network. The results of digestion showed that, CA was more helpful to slow down the release of free fatty acids and protect vitamin E during digestion. Compared with SPI-GA emulsion gel, SPI-CA emulsion gel had better physicochemical properties and stronger network structure. The results of this study may be useful in the development of anionic polysaccharides that interact with SPI, and they may provide new insights on the preparation of emulsion gels that slowly release fat-soluble nutrients.

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.

Amphiphilic Post‐Modification of Red Algae‐Derived Carrageenan Coatings for Balanced Marine Antifouling Applications

AbstractPolysaccharide coatings are of interest for marine antifouling applications because of their good marine antifouling properties and environmentally benign characteristics. However, the hydrophilic nature of polysaccharide coatings can lead to the adsorption of marine sediment, which can negatively impact their antifouling properties. Amphiphilic modification of polysaccharide coatings has been demonstrated to address these issues. In this study, we report a simple method for post‐modification of a sulfated polysaccharide carrageenan (CAR) coating to make it amphiphilic. A hydrophilic CAR coating is first formed on solid substrates, followed by grafting hydrophobic molecules onto the CAR‐coated surfaces through metal‐ion‐mediated coordinate bond formation. The resulting amphiphilic CAR coating effectively reduces both marine sediment (silt) adsorption and marine diatom adhesion, achieving a balanced marine antifouling performance.

Unveiling the culturable and non-culturable actinobacterial diversity in two macroalgae species from the northern Portuguese coast.

Actinomycetota, associated with macroalgae, remains one of the least explored marine niches. The secondary metabolism of Actinomycetota, the primary microbial source of compounds relevant to biotechnology, continues to drive research into the distribution, dynamics, and metabolome of these microorganisms. In this study, we employed a combination of traditional cultivation and metagenomic analysis to investigate the diversity of Actinomycetota in two native macroalgae species from the Portuguese coast. We obtained and taxonomically identified a collection of 380 strains, which were distributed across 12 orders, 15 families, and 25 genera affiliated with the Actinomycetia class, with Streptomyces making up approximately 60% of the composition. Metagenomic results revealed the presence of Actinomycetota in both Chondrus crispus and Codium tomentosum datasets, with relative abundances of 11% and 2%, respectively. This approach identified 12 orders, 16 families, and 17 genera affiliated with Actinomycetota, with minimal overlap with the cultivation results. Acidimicrobiales emerged as the dominant actinobacterial order in both macroalgae, although no strain affiliated with this taxonomic group was successfully isolated. Our findings suggest that macroalgae represent a hotspot for Actinomycetota. The synergistic use of both culture-dependent and independent approaches proved beneficial, enabling the identification and recovery of not only abundant but also rare taxonomic members.

Kappa-carrageenan and sodium alginate-based pH-responsive hydrogels for controlled release of methotrexate.

Despite remarkable progress in medical sciences, modern man is still fighting the battle against cancer. In 2022, only in the USA, 640 000 deaths and 2 370 000 patients were reported because of cancer. Chemotherapy is the most widely used for cancer treatments. However, chemotherapeutics have severe physicochemical side effects. Therefore, we have prepared poly(amididoamine) dendrimeric carrageenan (CG), sodium alginate (SA) and poly(vinyl alcohol) (PVA) hydrogels by using solution casting methodology. The constituents of hydrogels were cross-linked by mutable quantity of 3-aminopropyl(diethoxy)methyl silane (APDMS). Hydrogels were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscope and atomic force microscopy. Hydrogels exhibited higher swelling volumes in 5-7 pH range. In vitro biodegradation in ribonuclease-A solution and cytocompatibility analysis against DF-1 fibroblasts established their biodegradable and non-toxic nature, which enables them as a suitable carrier for chemotherapeutic compounds. Hence, methotrexate (MTX) as a model drug was loaded on CAP-8 hydrogel and its release was detected by the UV-visible spectrophotometer in phosphate-buffered saline (PBS) solution. In 13.5 h, 81.25% and 77.23% of MTX were released at pH 7.4 (blood pH) and 5.3 (tumour pH) in PBS, respectively. MTX was released by super case II mechanism and best fitted to zero-order and Korsmeyer-Peppas model. The synthesized APDMS cross-linked CG/SA/PVA dendrimeric hydrogels could be an efficient model platform for the effective delivery of MTX in cancer treatments.

Iota carrageenan linked barium ion nanoparticle synthesis for the selective targeted imaging and inhibition of cancer cells

Abstract The development of stable carrageenan nanoparticles connected to the sulfate functional group of carrageenan and barium ion for the use of selectively targeting cancer cell and imaging contrast to help with diagnosis (tracing/imaging) is the concern of the present research. This study provides an overview of ion substitution chemistry, highlighting the role of ions and how they affect the applicability of carrageenan. The characteristic of barium sulfate, which is widely used as radiopaque to provide contrast for diagnostic radiographic examinations in the gastrointestinal mucosa, is provided by its linkage with the barium ion despite K+’s natural binding with carrageenan. The additional role of the Ba ion linked carrageenan was found highly selective for cancer cell through the in vitro cell line assay; however, the nonattachability to the normal cell makes useful to trace and treat the cancer cell. The tracing is possible because of the barium sulfate functional group and its nanosize molecule, which shows precision medicine, fluorescence, and X-ray/CT imaging character, to be utilized as the diagnostic purpose, especially to tumor cell. The apoptosis from the Ba2+ ion by the inhibition of outflux of K+ to disturb the osmosis of cell and selectivity of the molecules because of high pKa (Logarithms of acid dissociation constant) value, which makes the drug more active anionic (nonpolar) form in the cancer cell and ionic form (polar) in the normal cell, which avoids the interaction with normal cell and facilitate the interaction with cancer cell. In conclusion, the cancer cell selectivity with fluorescence and radiopaque properties of Ba ion linked carrageenan makes the molecule useful for tracing, imaging, and treating cancer cell with high selectivity.

Carrageenan films as promising mucoadhesive ocular drug delivery systems

Polymer mucoadhesive films being developed for use in ophthalmology represent a new tool for drug delivery and are considered an alternative to traditional dosage forms. Due to their mucoadhesive properties, carrageenans (CRGs) are widely used in various forms for drug delivery. In this study, films based on CRGs of various structural types (κ/β, κ, x, and λ) for use in ophthalmology were studied. The films were loaded with the active substance echinochrome (ECH), a sea urchin pigment used in ophthalmology. Spectral data showed that ECH remained stable after its incorporation into the CRG films and did not oxidize for at least six months. Hydrophilic CRG films with a thickness of 10−12 µm were characterized in terms of their swelling and mucoadhesive properties. The rheological properties of solutions formed after film dissolution in artificial tears were also assessed. κ- and κ/β-CRG films with ECH exhibited pseudoplastic behavior after rehydrating films with an artificial tear solution. The CRG-loaded films had different swelling characteristics depending on the structure of the CRG used. The films based on highly sulfated CRGs dissolved in artificial tears, while the films of low-sulfated κ/β-CRG exhibited limited swelling. All studied ECH-loaded films exhibited mucoadhesive properties, which were evaluated by a texture analyzer using mucous tissue of the small intestine of the pig as a model. There was a slight prolongation of ECH release from CRG films in artificial tears. The effect of CRG/ECH on the epithelial cell lines of the outer shell of the human eye was investigated. At low concentrations, ECH in the composition of the CRG/ECH complex had no cytotoxic effect on corneal epithelial and conjunctival human cells. The use of ECH-containing films can prevent the drug from being immediately washed away by tears and help to retain it by increasing viscosity and having mucoadhesive properties.

Pharmacokinetics, tissue distribution, and subacute toxicity of oral carrageenan in mice

Carrageenan (CGN) is a typical sulfated polysaccharide widely applied in the food and pharmaceutical industries. Its in vivo behavior plays vital roles in understanding structural and biological functional relationships. The lack of UV chromophores in highly sulfated polysaccharides presents a challenge for their in vivo behavior studies. Therefore, this study aimed to develop a fast and effective quantitative fluorescence method for investigating the pharmacokinetics and tissue distribution of CGN. Fluorescence isothiocyanate labeling of CGN (FCGN) and microplate reader-based measurements were developed and validated to study its pharmacokinetics. These results showed that the FCGN concentration peaked at 3 h, the mean residence time was 36.6 h, and the clearance rate was 0.1 L/h/kg. Most of the FCGN was excreted in the feces, while 9.2 % was excreted in the urine, suggesting absorption and metabolism. The pharmacokinetic parameters indicated that the FCGN was absorbed quickly, eliminated slowly, and could remain in the body for a sustained profile. Moreover, ex vivo imaging and quantification of FCGN in tissues revealed that FCGN accumulated in the liver and kidney. Furthermore, oral administration of CGN or KOs for 14 days led to changes in liver and kidney indices. Histological analysis of significant organs revealed hepatocyte necrosis in the liver, renal tubular vacuolization in the kidney, and incomplete colonic epithelial cells. The KOs had a more significant effect on inflammatory cell infiltration than did CGNs. These in vivo findings laid the foundation for the study and application of CGN in food and pharmaceutical applications.

Synergistic adsorption of methylene blue with carrageenan/hydrochar-derived activated carbon hydrogel composites: Insights and optimization strategies

The study explores the use of hydrochar-derived activated carbon (AC) to improve the adsorption capacity and mechanical properties of carrageenan (CAR) hydrogel beads. Four distinct samples, with carrageenan to activated carbon ratios of 1:0 (CAR), 2:1 (CAC2), 4:1 (CAC4), and 10:1 (CAC10), were prepared. These polymeric beads underwent comprehensive evaluation for their methylene blue (MB) adsorption capacity, gel content (GC), and swelling ratio (SR). Increasing activated carbon content up to 50 % of carrageenan mass significantly enhanced GC and SR by 20.57 % and 429.24 %, respectively. Various analytical techniques were employed to characterize the composites, including FTIR, XRD, Raman Spectroscopy, BET, SEM, and EDS-Mapping. Batch adsorption tests investigated the effects of pH, contact time, dye concentration, and temperature on MB adsorption. Maximum adsorption capacities for CAR, CAC10, CAC4, and CAC2 were 475.48, 558.54, 635.93, and 552.35 mg/g, respectively, under optimal conditions. Kinetic models (Elovich and pseudo-second-order) and isotherm models (Temkin for CAR and Freundlich for CAC10, CAC4, and CAC2) fitted well with the experimental data. Thermodynamic analysis showed spontaneous, exothermic MB adsorption. Primary mechanisms include electrostatic attraction, hydrogen bonding, n-π, and π-π stacking. The study highlights enhanced adsorption capacity of carrageenan hydrogel via carrageenan/activated carbon composites, providing cost-effective wastewater treatment.

Cation Effect in Polysaccharide-Based Hydrogel Beads Produced for Europium Adsorption from Aqueous Solutions

In recent decades, renewable and biodegradable polysaccharide-based hydrogels have enjoyed wide applicability among them also as adsorbents for heavy metal removal from wastewaters. Herein we prepared hydrogel beads from iota and kappa carrageenans using a variety of salts as crosslinkers, that were tested for the first time in europium ion (Eu3+) sorption from an aqueous solution as representative lanthanide. The type of the salt, and especially the valance and the hydrated radius of the cation, were found to dictate hydrogel bead formation and structure and, therefore, the Eu3+ sorption yield. The results of ATR-FTIR, SEM and TGA analyses to characterize the iota carrageenan hydrogel beads that were prepared with alkali cations, before and after interaction with Eu3+, indicate that the adsorbent prepared with LiCl was much stiffer and more stable than those prepared with NaCl or KCl. The iota carrageenan beads that were prepared with LiCl were also reused 5 times while exhibiting high adsorption capacities.

Effects of dietary binder sources on growth, digestive enzymes activity, and gut barrier function and microbial composition of larval largemouth bass (Micropterus salmoides)

A 4-week feeding trail was conducted to explore the impacts of dietary binder sources on growth performance, digestive enzymes activities, intestinal microbiota, and expression of genes involved in tight junctions and nutrient sensing pathway of larval largemouth bass with initial body weight of 8.43 ± 0.01 mg (13 day after hatching). Five isolipidic micro-diets were formulated with different binder sources including sodium alginate (SA), carrageenan (CG), hydroxypropyl methyl cellulose (HPMC), gelatin (GT), and starch (SC). The results revealed that the highest growth performance was observed in the CG group, and meanwhile, the promotion effects of SA and GT was statistically higher than that of HPMC and SC groups. SA, CG and GT had positive effects on digestive enzymes activity compared to other groups. Gene expression results showed that SA, CG and GT groups up-regulated the expression of tight junction genes, zo-1, claudin-4 and claudin-7, and activated the genes involved in the TOR signaling pathway, including tor, akt1, s6kβ1 and s6. Among all the groups, the CG had the most significant activation effect on TOR signaling pathway. Bacterial 16S rRNA V3–4 region analysis showed that the addition of different dietary binders influenced the diversity of intestinal microbial communities. The inclusion of SA and CG groups reduced the relative abundance of Proteobacteria and Actinobacteria at the phylum level, while at the genus level, the relative abundance of Rhodococcus and Achromobacter increased and the abundance of Plesiomonas was inhibited. In summary, dietary binder sources affected the growth, digestive function, gut barrier function and microbial composition, and nutrient sensing, and SA and CG could be suggested as the optimal dietary binders for formulation of micro-diets for largemouth bass larvae.

Changes in Tight Junction Protein Expression Levels but Not Distribution in Commercial White and Brown Laying Hens Supplemented with Chondrus crispus or Ascophyllum nodosum Seaweed.

It is proposed that prebiotic diet supplements improve intestinal function, in part by improving the barrier function of the intestinal epithelium with an associated increase in the expression of tight junction proteins, including occludin and zonula occludens-1 (ZO-1). We examined the expression of these proteins in two strains of laying hens (Lohman LSL-lite (White) and Lohman Brown-lite (Brown)) who were supplemented or not with 3% Chondrus crispus or 0.5% Ascophyllum nodosum seaweeds from 31 to 72 weeks of age. Occludin was localized to the lateral surfaces and across the intestinal epithelium in all animals. Reactivity for ZO-1 was concentrated at the apicolateral epithelial cell membrane border. Mood's median test indicated that White hens may express more occludin in villus epithelium (median intensity 3.5 vs. 2.5 in Brown hens, p = 0.06) but less ZO-1 in the deep cryptal epithelium (median intensity 1.5 vs. 2.5 in Brown hens, p = 0.06). Western blotting also showed higher levels of occludin in White than Brown hens (p < 0.05). A decrease in ZO-1 Western blot expression was associated with Chondrus crispus supplementation in comparison to controls (p < 0.05), but not with Ascophyllum nodosum supplementation (p > 0.05). In conclusion, genetic strain and dietary seaweed supplements affect tight junction regulatory protein expression levels but do not impact the anatomical distribution, as seen in cryosections.

Chemical, pyrolysis, combustion properties and mechanism analysis of wood treated with biomass-based carrageenan-collagen modified ammonium polyphosphate

Biomass-based flame retardants are characterized by readily available raw materials and are environmentally friendly, making the design of green and efficient biomass-based flame retardants a critical direction in the development of flame-retardant technology. In this study, a novel biomass-based flame retardant (Acc) was developed using ammonium polyphosphate (APP) as a raw material in combination with the biomass materials carrageenan (CAR) and collagen (COL). Flame-retardant wood was prepared via ultrasonic impregnation. Via various analytical and testing methods, such as the Limiting Oxygen Index (LOI), thermogravimetric analysis, scanning electron microscopy, Raman spectroscopy, cone calorimetry, and thermogravimetric–infrared coupling, the combustion performance of biomass-based flame retardants on wood was investigated to elucidate the flame-retardant mechanism. The results indicated that the flame retardant with a CAR:COL:APP ratio of 1:1:3 exhibited the best flame-retardant effect, with an LOI of 31.8 %. The peak heat release rate was reduced to 53.8 % compared with that of untreated wood, and both the peak smoke release rate and total smoke release were reduced by 63.2 % and 49.2 %, respectively, demonstrating a significant smoke-suppression effect. Analysis of the mechanism revealed that APP, COL and CAR generated non-combustible gases such as ammonia and gases containing P and S when exposed to fire. These gases dilute oxygen and eliminate •H and •HO radicals in the gas phase, thereby exerting flame-retardant effects. Acc promotes the formation of a dense crosslinked carbon layer containing N=C, N-C/P-N, N-H, and C-O-P. This carbon layer acts as a physical barrier, isolating oxygen (O2), blocking gas emissions, and slowing heat exchange. This study provides a new avenue for the development of green and sustainable flame retardant wood.

Three-Dimensional Printing of Red Algae Biopolymers: Effect of Locust Bean Gum on Rheology and Processability.

Seaweeds, rich in high-value polysaccharides with thickening/gelling properties (e.g., agar, carrageenan, and alginate), are extensively used in the food industry for texture customization and enhancement. However, conventional extraction methods for these hydrocolloids often involve potentially hazardous chemicals and long extraction times. In this study, three red seaweed species (Chondrus crispus, Gelidium Corneum, and Gracilaria gracilis) commercialized as food ingredients by local companies were chosen for their native gelling biopolymers, which were extracted using water-based methodologies (i.e., (1) hydration at room temperature; (2) stirring at 90 °C; and (3) centrifugation at 40 °C) for production of sustainable food gels. The potential use of these extracts as bioinks was assessed employing an extrusion-based 3D printer. The present work aimed to study the gelation process, taken place during printing, and assess the effectiveness of the selected green extraction method in producing gels. To improve the definition of the printed gel, two critical printing parameters were investigated: the addition of locust bean gum (LBG) at different concentrations (0, 0.5, 1, 1.5, 2, and 2.5%) and printing temperature (30, 40, 60, and 80 °C). Rheological results from a controlled-stress rheometer indicated that gels derived from G. corneum and G. gracilis exhibited a lower gel strength (lower G' and G″) and excessive material spreading during deposition (lower viscosity) than C. crispus. Thus, G' was around 5 and 70 times higher for C. crispus gels than for G. corneum and G. gracilis, respectively. When increasing LBG concentration (0.5 to 2.5% w/w) and lowering the printing temperature (80 to 30 °C), an enhanced gel matrix definition for G. corneum and G. gracilis gels was found. In contrast, gels from C. crispus demonstrated greater stability and were less influenced by these parameters, showcasing the potential of the seaweed to develop sustainable clean label food gels. Eventually, these results highlight the feasibility of using algal-based extracts obtained through a green procedure as bioinks where LBG was employed as a synergic ingredient.

Effect of Xanthan gum seed coating on seed germination and seedling vigour of finger millet (Eleusine coracana L.)

Six Hydrophilic polymers Xanthan Gum, Iota Carrageenan, Kappa Carrageenan, Agar Agar, Food grade Agar and Gellan Gum were studied for polymerization potential and water holding capacities. Among the six polymers, Xanthan gum and Iota Carageenan recorded the maximum values for water holding capacities of 38.27 ml/g and 34.17 ml/g and were forwarded for the Seed coating experiment. Coating experiments consist of twodosages of polymer powders (10g, and 20g /kg) and two concentrations of sticking agent (water 5ml and 10 ml). Coated seeds exposed to seed germination studies against untreated seeds. Results revealed that Finger millet seeds coated with 20 g Xanthan gum + 10 ml water as sticker recorded the maximum values for seed germination (87%), seedling length (26.23cm), dry matter production (12.47mg 10 seedlings-1)and Vigour Index I (2282) and II (1084).The % increase over the control was 7 for seed germination, 56 for seedling length (cm), 21 for dry matter production (mg) ,69 for seedling vigour index I and 31for seedling vigour index II. From the studies it could be concluded that Finger millet seeds coated with the Xanthangum @20 g can be recommended as pre sowing seed treatment for improving the Seed Germination and seedling vigour.

The Effect of seaweed (Eucheuma cottonii) extract and duration of soaking on reduction of Copper (Cu) level in Freshwater Mussel (Pilsbryoconcha exilis)

Freshwater Mussels (Pilsbryoconcha exilis) are filter-feeder animals that have eating habits by filtering food in the water, making it possible that heavy metal copper (Cu) will accumulate in the body of the mussel. One type of seaweed that can absorb heavy metals is Eucheuma cottonii because it contains iota carrageenan (65%) which is a sulfated polysaccharide containing hydroxyl groups and carboxyl groups capable of retaining and accumulating heavy metals. In addition E. cottoni as a biosorbent in the aquatic environment. This research aims to determine the effect of extract concentration and the best soaking time in reducing copper (Cu) levels. This research was conducted from April to May 2023. In this study, the concentrations used were 6%, 10%, and 14% with a period of 45 minutes, 90 minutes, and 135 minutes. The results showed that the concentration of 14% extract with a soaking time of 135 minutes showed the highest decrease in copper (Cu) levels of 1.298 mg/kg or 87.10% and the lowest decrease in copper (Cu) metal levels at a concentration of 6% with a soaking time of 45 minutes of 0.442 mg/kg or 29.68%.

Influence of structural colour on the photoprotective mechanism in the gametophyte phase of the red alga Chondrus crispus.

Marine life is populated by a huge diversity of organisms with an incredible range of colour. While structural colour mechanisms and functions are usually well studied in marine animal species, there is a huge knowledge gap regarding the marine macroalgae (red, green and brown seaweeds) that have structural coloration and the biological significance of this phenomenon in these photosynthetic organisms. Here we show that structural colour in the gametophyte life history phase of the red alga Chondrus crispus plays an important role as a photoprotective mechanism in synergy with the other pigments present. In particular, we have demonstrated that blue structural coloration attenuates the more energetic light while simultaneously favouring green and red light harvesting through the external antennae (phycobilisomes) which possess an intensity-dependent photoprotection mechanism. These insights into the relationship between structural colour and photosynthetic light management further our understanding of the mechanisms involved.