Optimized Incorporation of Silver Nanoparticles onto Cotton Fabric Using k-Carrageenan Coatings for Enhanced Antimicrobial Properties.

The incorporation of bactericidal properties into textiles is a widely sought-after aspect, and silver nanoparticles (AgNPs) can be used for this. Here, we evaluate a strategy for incorporating AgNPs into a cotton fabric. For this purpose, a bactericidal textile coating based on a composite of AgNPs and kappa-carrageenan (k-CA) was proposed. The composite was obtained by heating the silver precursor (AgNO3) directly in k-CA solution for green synthesis and in situ AgNPs stabilization. Cotton substrates were added to the heated composite solution for surface impregnation and hydrogel film formation after cooling. Direct synthesis of AgNPs on a fabric was also tested. The results showed that the application of a coating based on k-CA/AgNPs composite can achieve more than twice the silver loading on the fabric surface compared to the textile subjected to direct AgNPs incorporation. Furthermore, silver release tests in water showed that higher Ag+ levels were reached for k-CA/AgNPs-coated cotton. Therefore, inoculation tests with the bacteria Staphylococcus aureus (SA) using the agar diffusion method showed that samples covered with the composite resulted in significantly larger inhibition halos. This indicated that the use of the composite as a coating for cotton fabric improved its bactericidal activity against SA.

Performance and analysis of kappa-carrageenan hydrogel for PFOA-contaminated soil remediation wastewater treatment.

Perfluorooctanoic acid is an emerging pollutant with exceptional resistance to degradation and detrimental environmental and health impacts. Conventional physical and chemical processes for Perfluorooctanoic acid are either expensive or inefficient. This study developed an environmentally sustainable and cost-effective gravity-driven kappa-carrageenan (kC)-based hydrogel for perfluorooctanoic acid (PFOA) removal from synthetic and actual wastewater. Two kC filters were prepared by mixing activated carbon (AC) or vanillin (V) with the kC hydrogel to optimize the hydrogel selectivity and water permeability. Experimental work revealed that the PFOA rejection and water permeability increased with the AC and V concentrations in the kC hydrogel. Experiments also evaluated the impact of feed pH, PFOA concentration, hydrogel composition, and hydrogel thickness on its performance. Due to pore size shrinkage, the AC-kC and V-kC hydrogels achieved the highest PFOA rejection at pH 4, whereas the water flux decreased. Increasing the PFOA concentration reduced water flux and increased PFOA rejection. For 2 cm hydrogel thickness, the water flux of 3%kC-0.3%AC and 3%kC-3%V hydrogels was 25.6 LMH and 21.5 LMH, and the corresponding PFOA rejection was 86.9% for 3%kC-0.3%AC and 85.7% for 3%kC-3%V. Finally, the kC-0.3%AC hydrogel removed 81.1% of PFOA from wastewater of 179 mg/L initial concentration compared to 79.3% for the kC-3%V hydrogel. After three filtration cycles, the water flux decline of 3%kC-0.3%AC was less than 10%. The gravity dead-end kC hydrogel provides sustainable PFOA wastewater treatment with biodegradable and natural materials.

Iota-carrageenan as a regenerating system for Eu3+ recovery: adsorption/desorption cycles.

Renewable and biodegradable polysaccharides attract attention as environmentally friendly adsorbents for the removal of heavy metals from wastewater. One such group, is carrageenan, of which were recently successfully employed to adsorb representative lanthanide and actinide ions. Herein, iota-carrageenan-based hydrogels were used to adsorb europium ions (Eu3+) from water solutions, followed by desorption of the ions from the hydrogel beads and recycling of the beads three times. It was found that sorption yields from a 500 mg/L Eu3+ ion solution with beads that were prepared with 1 or 2 wt/v% aqueous solution of iota-carrageenan with CaCl2 (0.5 M) reached maximum sorption yield of 50% and 65%, correspondingly, after 1 h. In addition, the sorption kinetics followed the pseudo second-order model controlled by chemisorption. Desorption yields in the first cycle using NaNO3 (1 M) with both preparations were 57% and 74%, respectively. The sorption yields increased during the second and third cycles and were efficient in the overall pH range. Cryo-SEM, SEM, SEM-EDS and TGA analyses verified the adsorption and desorption of Eu3+ ions to and from the iota beads and that the Ca2+ ions that initially crosslinked the hydrogel were replaced during the cycles by Eu3+ or Na+ ions. In addition, the beads were stable and easily reusable for several sorption/desorption cycles. Furthermore, after sorption, the beads were characterised by a porous structure, such that beads prepared with a 2 wt/v% aqueous solution of iota-carrageenan yielded a more porous, ordered structure, and after desorption, the bead textures became even more porous.

Tailored alginate sponges loaded with κ-carrageenan beads for controlled release of curcumin.

This study presents an innovative approach to develop and characterize an alginate sponge containing κ-carrageenan (κ-CRG) beads loaded with curcumin. The beads were fabricated using varying concentrations of κ-CRG, and their properties were extensively evaluated using inverted phase-contrast microscopy, Scanning Electron Microscopy (SEM), FTIR, swelling behavior, mass distribution, encapsulation efficiency, in vitro drug release and kinetics of drug release. Beads formulated with specific concentrations of κ-CRG that exhibited optimal performance were then integrated into an alginate sponge matrix, which underwent similar comprehensive testing procedures as the individual beads. The characterized beads displayed a spherical morphology, a notable swelling degree of approximately 146 %, excellent mass uniformity, encapsulation efficiencies higher than 90 % and drug release rate exceeding 70 %. Moreover, the alginate sponge formulation demonstrated a satisfactory drug release profile of 67.9 ± 0.6 %. In terms of drug release kinetics, the Higuchi model was the most effective in explaining the release of curcumin from beads and sponge. These findings underscore the potential of both the beads and the sponge as effective vehicles for the controlled delivery of curcumin, positioning them as promising candidates for pharmaceutical applications across various fields.

Comparative analysis of classic network vs. nanogel junction network in konjac glucomannan/kappa carrageenan hybrid hydrogels.

The three-dimensional network architecture of hydrogels significantly influences their mechanical and physical properties; therefore, understanding them is essential for designing optimized hydrogel-based biomaterials. This study presents a comparative analysis of two hybrid hydrogels composed of konjac glucomannan (KGM) and kappa carrageenan (KCAR) with the same stiffness (5.2-5.7 kPa and 1.6-1.7 kPa) thus similar cross-linking density but different network architectures: a classic network formed by extended polysaccharide interactions and a nanogel junction network where nanoscale cross-linked KCAR (KCAR-NGs) links KGM chains. The mechanical behavior, dissolution, and diffusion characteristics were examined, revealing that the classic network demonstrates superior tensile resistance, elongation, and solvent-induced swelling resistance, leading to slower dissolution rates and higher viscosity. Conversely, the nanogel junction network offers higher permeability for small molecules and faster dissolution, suggesting a more open network structure. These findings highlight the nanogel-based hydrogels' advantages for biomedical applications requiring stability, permeability, and rapid dissolution without high temperatures or chelating agents. This study underscores the potential of nanogel junction networks to balance hydrogel stiffness and permeability, advancing the design of hydrogel-based biomaterials.

Quality Evaluation of Chicken Liver Pâté Affected by Algal Hydrocolloids Addition: A Textural and Rheological Approach.

Hydrocolloids are used in spreadable meat or poultry products to improve consistency, emulsion stability and water retention, resulting in products with desired functional and organoleptic properties. The scope of the work was to evaluate the addition of three divergent algal hydrocolloids (κ-carrageenan, ι-carrageenan, furcellaran) at four different concentrations (0.25, 0.50, 0.75, and 1.00% w/w) on the physicochemical, textural, rheological and organoleptic properties of model chicken liver pâté (CLP) samples. Overall, the highest hardness and viscoelastic moduli values of the CLP samples were reported when κ-carrageenan and furcellaran were utilized at a concentration of 0.75% w/w (p < 0.05). Furthermore, increasing the concentrations of the utilized hydrocolloids led to increase in the viscoelastic moduli and hardness values of CLP. Compared to the control sample, an increase in spreadability was reported in the CLP samples with the addition of hydrocolloids. Finally, the use of algal hydrocolloids proved to be an effective way to modify the techno-functional properties of CLP.

Healing Potential of the Marine Polysaccharides Carrageenan and Ulvan on Second-Degree Burns.

The treatment of second-degree burn wounds presents a significant clinical challenge, often characterized by prolonged healing times and risk of complications. In this study, the wound healing potential of bioactive marine sulfated polysaccharides ulvan and carrageenan formulated in gels at concentrations of 1.5%, 5.0%, and 10% w/w was evaluated. Hairless female SKH-hr2 mice (n = 7 per treatment) with burn-inflamed skin were treated with the polysaccharide-based gels, and the therapeutic efficacy was assessed using a comprehensive array of evaluation methods, including a histopathological analysis, clinical observation, photo-documentation, an image analysis, an evaluation of biophysical skin parameters, and FT-IR spectroscopy. Our findings indicate that the 10% w/w carrageenan gel exhibited significant enhancement in wound healing, particularly in the early stages of the healing process. This was evidenced by the restoration of the α-helix structure of collagen and the configuration of glycosaminoglycans, as demonstrated by FT-IR absorption bands of the skin both in vivo and ex vivo. Furthermore, the 5% w/w ulvan gel also demonstrated notable efficacy in promoting wound healing, particularly in the later stages of the healing process. These results suggest that carrageenan and ulvan gels hold promise for improving the efficiency of wound healing in second-degree burn wounds. Our study contributes to the understanding of the therapeutic potential of marine polysaccharides and provides insights into their mechanism of action in promoting wound healing.

Synergistic effects of starch and carrageenan from Kappaphycus alvarezii in composite film formation: Physicochemical and degradable properties.

Rising concerns around plastic pollution from single-use plastic (SUPs), especially food packaging, have driven interest in sustainable alternatives. As such, algae biomass has gained attention for bioplastic production due to algae's rapid growth and abundant polysaccharides. This research focuses on extracting carrageenan from Kappaphycus alvarezii, extensively cultivated in Sabah, Malaysia, and utilizing it in combination with starch and glycerol to develop algae-based films. The physicochemical properties and degradation rate of these films were evaluated, revealing that the addition of carrageenan enhanced overall thermal stability meanwhile increasing water solubility, water content but reducing the degradation rate and swelling degree. This is primarily due to the crystalline structures of carrageenan, which provide a more rigid arrangement compared to the network of starch polymers. However, the incorporation of starch into the blends has enhanced the elongation and surface morphology, resulting in more balanced properties. Overall, these carrageenan films displayed impressive thermal, mechanical, and biodegradability characteristics, establishing their viability as substitutes for conventional plastics.

Structure-Elasticity Relationships in Hybrid-Carrageenan Hydrogels Studied by Image Dynamic Light Scattering, Ultra-Small-Angle Light Scattering and Dynamic Rheometry.

Hybrid-carrageenan hydrogels are characterized using novel techniques based on high-resolution speckle imaging, namely image dynamic light scattering (IDLS) and ultra-small-angle light scattering (USALS). These techniques, used to probe the microscopic structure of the system in sol-gel phase separation and at different concentrations in the gel phase, give access to a better understanding of the network's topology on the basis of fractals in the dense phase. Observations of the architecture and the spatial and the size distributions of gel phase and fractal dimension were performed by USALS. The pair-distance distribution function, P(r), extracted from USALS patterns, is a new methodology of calculus for determining the network's internal size with precision. All structural features are systematically compared with a linear and non-linear rheological characterization of the gels and structure-elasticity relationships are identified in the framework of fractal colloid gels in the diffusion limit.

A disulfide bond mutant of Pseudoalteromonas porphyrae κ-carrageenase conferred improved thermostability and catalytic activity and facilitated its utilization in κ-carrageenan industrial waste residues recycling.

In this study, Discovery Studio was employed to predict the potential disulfide bond mutants of the catalytic domain of Pseudoalteromonas porphyrae κ-carrageenase to improve the catalytic activity and thermal stability. The mutant N205C-G239C was identified with significantly increased catalytic activity toward κ-carrageenan substrate, with activity 4.28 times that of WT. The optimal temperature of N205C-G239C was 55 °C, 15 °C higher than that of WT. For N205C-G239C, the t1/2 value at 50 °C was 52 min, 1.41 times that of WT. The microstructural analysis revealed that the introduced disulfide bond N205C-G239C could create a unique catalytic environment by promoting favorable interactions with κ-neocarratetraose. This interaction impacted various aspects such as product release, water molecule network, thermodynamic equilibrium, and tunnel size. Molecular dynamics simulations demonstrated that the introduced disulfide bond enhanced the overall structure rigidity of N205C-G239C. The results of substrate tunnel analysis showed that the mutation led to the widening of the substrate tunnel. The above structure changes could be the possible reasons responsible for the simultaneous enhancement of the catalytic activity and thermal stability of mutant N205C-G239C. Finally, N205C-G239C exhibited the effective hydrolysis of the κ-carrageenan industrial waste residues, contributing to the recycling of the oligosaccharides and perlite.

Physical characteristics of quercetin pulmospheres using combination of alginate-carrageenan: Effect of polymer concentration.

Indonesia is the second country with the highest number of tuberculosis (TB) cases in the world and the first in Southeast Asia, according to WHO Global Report 2020. Quercetin has been tried as an alternative therapy and was found effective. This study aims to optimize quercetin pulmospheres using combination polymers and study its characteristics as an inhalation delivery system. Combination polymers provide the advantages of safe, mucoadhesive, and compact pulmospheres. Pulmospheres were made as formula F1, F2, and F3 (polymer ratios of 1:1, 1:2, and 1:3), respectively. Pulmospheres were made with quercetin 0.2%, alginate-carrageenan (total concentration of 1.8%), and CaCl2 0.5 M. Characterization of particle size, morphology, moisture content (MC), yield, drug loading, and entrapment efficiency (EE) were conducted. The yield range was from 83.89 to 86.30% ± 4.59%. MC range was from 4.23 to 5.12% ± 0.05%. Particle size was <3 µm (between 2.19 and 2.76 ± 0.149 µm), spherical shape and smooth surface. EE range was 60.69% ± 4.45% to 77.86% ± 1.74% and the drug loading range was 1.66-2.09% ± 0.15%. F2 formula with a polymer ratio of 1:2 was the best quercetin pulmospheres. Potential pulmospheres will then be recommended for in vitro release and in vivo study.

Formulation of novel low-sodium salts using potassium salts and dietary polysaccharide.

Potassium citrate (KC) and potassium lactate (KL) are considered as salt replacers due to their saltiness, processing advantages, and health benefits. However, the obvious bitter taste associated with these compounds has limited their use in salt substitutes. Despite this challenge, little attention has been paid to improving their sensory properties. This study provided evidence that dietary polysaccharide carrageenan can effectively mask the bitterness of KC and KL by specifically binding K+ and forming double helix chains. A highly accurate prediction model was then established for the saltiness and bitterness of low-sodium salts using mixture design principles. Three low-sodium salt formulas containing different potassium salts (KC, KL, KCl), NaCl, and carrageenan were created based on the prediction model. These formulas exhibited favorable saltiness potencies (>0.85) without any noticeable odor, preserving the sensory characteristics of high-sodium food products like seasoning powder while significantly reducing their sodium content. This research provides a promising approach for the food industry to formulate alternative low-sodium products with substantially reduced sodium content, potentially contributing to decreased salt intake.

Evaluation of carrageenans extracted by an eco-friendly technology as source for gelled matrices with potential food application.

Red macroalgae are considered an immense source of hydrocolloids (agar and carrageenan) that are gaining momentum in the food industry as an alternative to animal-based ones, like gelatin. This work evaluates carrageenans extracted from four different red macroalgae (Chondrus crispus, Mastocarpus stellatus, Sarcopeltis skottsbergii and Gigartina pistillata) by an eco-friendly process (hydrothermal extraction), for their possible employment as food additives considering purity requirements stated by the European Regulation. In general, carrageenans presented a suitable composition, although some sample presented lower sulfate content than 15 % and higher As content than 3 mg/kg, being only carrageenans from Chondrus crispus and Sarcopeltis skottsbergii appropriate for gelled matrices formulation. Different concentrations of hydrocolloids (1-5 %) and salts (0.1-1 M NaCl, CaCl2 and KCl) were evaluated to reach a desired consistency. Rheological behavior of said gels revealed a gel-like behavior, with G' > G" and practically frequency independency of the parameters. Overall, gels formulated with KCl achieved higher G' with maximum values of 100-1000 Pa, whereas the commercial gelled dessert (used as control) only achieved values of around 10 Pa. After 3 months of cold storage, all gels exhibited a strengthening of the gelled matrix, without water syneresis. The colorimetric parameters were also evaluated, showing higher inclination for red and yellow tones with modest lightness values (around 60 %). In this work, hydrothermally extracted carrageenans from Chondrus crispus and Sarcopeltis skottsbergii were assessed, laying the groundwork for further studies in this area.

A novel biodegradable film based on chicken gelatin and κ-carrageenan cross-linked with oxidized phenolic compounds.

Natural and renewable polymers are gradually replacing petroleum-based plastics, mostly as a result of environmental concerns. Moreover, upcycling industrial food waste into new added-value products is a creative approach that is crucial for cleaner and more sustainable manufacturing. The aim of this study was to obtain an environmentally friendly biodegradable film using a combination of k-carrageenan (KCAR) and chicken gelatin (CGEL), which obtained from poultry by-products. The effects of varying concentrations of KCAR (0-2%) on the physical, permeability, textural, thermal, and microstructural properties of CGEL/KCAR composite films were evaluated. The findings demonstrated that an increase in KCAR enhanced the lightness and opacity levels of the films. Water vapor permeability (WVP) values reduced as the KCAR concentration increased. The lowest WVP value (0.0012 g.mm/h.m2.kpa) was seen in the treatment with 2% KCAR. Tensile strength (TS) values increased with increasing KCAR. The films' thermal stability was increased by the addition of KCAR. Microstructure assessments revealed a more compact and smooth structure in the KCAR-containing treatments, indicating improvements in WVP, thermal stability, and TS. Compared to the commercial cattle gelatin film, the CGEL film had higher TS and lower water solubility (WS). Overall, this study showed that the physical, mechanical, barrier and thermal and microstructural qualities of gelatin-based films may be enhanced by combining CGEL and KCAR to create an effective biodegradable film. Moreover, the comparison study between commercial cattle and chicken gelatin films revealed that cross-linked chicken gelatin films would be a suitable alternative for bovine gelatin films in the production of biodegradable film.

Exploring the amyloid degradation potential of nanoformulated carrageenan-bridging in vitro and in vivo perspectives.

Amyloids, with their ß-sheet-rich structure, contribute to diabetes, neurodegenerative diseases, and amyloidosis by aggregating within diverse anatomical compartments. Insulin amyloid (IA), sharing structural resemblances with amyloids linked to neurological disorders, acts as a prototype, while compounds capable of degrading these fibrils hold promise as therapeutic agents for amyloidosis intervention. In this research, liposomal nanoformulated iota carrageenan (nCG) was formulated to disrupt insulin amyloids, demonstrating about a 17-20 % higher degradation efficacy compared to conventional carrageenan through thioflavin T fluorescence, dynamic light scattering analysis, and turbidity quantification. The biocompatibility of the nCG and nCG-treated insulin amyloids was evaluated through MTT assay, live-dead cell assay on V79 cells, and hemolysis testing on human blood samples to establish their safety for use in vitro. Zebrafish embryos were utilized to assess in vivo biocompatibility, while adult zebrafish were employed to monitor the degradation capacity of IA post subcutaneous injection, with fluorescence emitted by the fish captured via IVIS. This demonstrated that the formulated nCG exhibited superior anti-amyloid efficacy compared to carrageenan alone, while both materials demonstrated biocompatibility. Furthermore, through docking simulations, an exploration was conducted into the molecular mechanisms governing the inhibition of the target protein pancreatic insulin by carrageenan.

Ultrasound Depolymerization and Characterization of Poly- and Oligosaccharides from the Red Alga Solieria chordalis (C. Agardh) J. Agardh 1842.

Red seaweed carrageenans are frequently used in industry for its texturizing properties and have demonstrated antiviral activities that can be used in human medicine. However, their high viscosity, high molecular weight, and low skin penetration limit their use. Low-weight carrageenans have a reduced viscosity and molecular weight, enhancing their biological properties. In this study, ι-carrageenan from Solieria chordalis, extracted using hot water and dialyzed, was depolymerized using hydrogen peroxide and ultrasound. Ultrasonic depolymerization yielded fractions of average molecular weight (50 kDa) that were rich in sulfate groups (16% and 33%) compared to those from the hydrogen peroxide treatment (7 kDa, 6% and 9%). The potential bioactivity of the polysaccharides and low-molecular-weight (LMW) fractions were assessed using WST-1 and LDH assays for human fibroblast viability, proliferation, and cytotoxicity. The depolymerized fractions did not affect cell proliferation and were not cytotoxic. This research highlights the diversity in the biochemical composition and lack of cytotoxicity of Solieria chordalis polysaccharides and LMW fractions produced by a green (ultrasound) depolymerization method.

Chitosan-carrageenan microbeads containing nano-encapsulated curcumin: Nano-in-micro hydrogels as alternative-therapeutics for resistant pathogens associated with chronic wounds.

Antimicrobial resistance is an issue of global relevance for the treatment of chronic wound infections. In this study, nano-in-micro hydrogels (microbeads) of chitosan and κ-carrageenan (CCMBs) containing curcumin-loaded rhamnosomes (Cur-R) were developed. The potential of Cur-R-CCMBs for improving the antibacterial activity and sustained release of curcumin was evaluated. Curcumin-loaded rhamnosomes (rhamnolipids functionalized liposomes) had a mean particle size of 116 ± 7 nm and a surface-charge of -24.5 ± 9.4 mV. The encapsulation efficiency of curcumin increased from 42.83 % ± 0.69 % in Cur-R to 95.24 % ± 3.61 % respectively after their embedding in CCMBs. SEM revealed smooth surface morphology of Cur-R-CCMBs. FTIR spectroscopy confirmed the presence of weak electrostatic and hydrophobic interactions among curcumin, rhamnosomes, and microbeads. Cur-R-CCMBs had demonstrated significant antibacterial activity against multi-drug resistant chronic wound pathogens including Staphylococcus aureus and Pseudomonas aeruginosa. Cur-R-CCMBs also exhibited significantly higher anti-oxidant (76.85 % ± 2.12 %) and anti-inflammatory activity (91.94 % ± 0.41 %) as well as hemocompatibility (4.024 % ± 0.59 %) as compared to pristine microbeads. In vivo infection model of mice revealed significant reduction in the viable bacterial count of S. aureus (∼2.5 log CFU/mL) and P. aeruginosa (∼2 log CFU/mL) for Cur-R-CCMBs after 5 days. Therefore, nano-in-micro hydrogels can improve the overall efficacy of hydrophobic antimicrobials to develop effective alternative-therapeutics against resistant-pathogens associated with chronic wound infections.

Fabrication of smart nanogel based on carrageenan and green coffee extract as a long-term antifouling agent to improve biofilm prevention in food production.

This study investigates the extract of the bioactive compounds from green coffee extract (GCE) and the loading of two different concentrations of GCE (1% and 2%) onto carrageenan nanogels (CAR NGs) to compare their antibacterial and antibiofilm effects with unloaded nanogels (NGs). The bioactive compounds of GCE were characterized using GC-MS analysis. The GCE1 and GCE2 were successfully deposited onto the surface of CAR NGs. The antibacterial and antibiofilm potential of prepared NGs were conducted against some foodborne pathogens (E. coli O157, Salmonella enterica, Staphylococcus aureus, and Listeria monocytogenes). The results of GC-MS analysis indicated that there were identified 16 bioactive compounds in GCE, including caffeine (36.27%), Dodemorph (9.04%), and D-Glycero-d-ido-heptose (2.44%), contributing to its antimicrobial properties. The antibacterial coatings demonstrated a notable antimicrobial effect, showing zone of inhibition (ZOI) diameters of up to 37 mm for GCE2 loaded CAR NGs. The minimum inhibitory concentration (MIC) values for GCE2 loaded CAR NGs were 80 ppm for E. coli O157, and 120 ppm for S. enterica, S. aureus, and L. monocytogenes, achieving complete bacterial inactivation within 10-15 min of exposure. Both GCE1 and GCE2 loaded CAR NGs significantly reduced biofilm cell densities on stainless steel (SS) materials for E. coli O157, S. enterica, S. aureus, and L. monocytogenes, with reductions ranging from 60% to 95%. Specifically, biofilm densities were reduced by up to 95% for E. coli O157, 89% for S. enterica, 85% for S. aureus, and 80% for L. monocytogenes. Results of the toxicity evaluation indicated that the NGs were non-toxic and biocompatible, with predicted EC50 values proved their biocompatibility and safety. These results recommended that GCE loaded CAR NGs are promising as natural antimicrobial agents for enhancing food safety and extending shelf life. Further, the study concluded that incorporating GCE into CAR NGs is an effective strategy for developing sustainable antimicrobial coatings for the food industry and manufacturing.

Physicochemical properties and in vitro digestive behavior of astaxanthin loaded Pickering emulsion gel regulated by konjac glucomannan and κ-carrageenan.

This study aimed to elaborate the combination effect of polysaccharides on physicochemical properties and in vitro digestive behavior of astaxanthin (AST)-loaded Pickering emulsion gel. AST-loaded Pickering emulsion gel was prepared by heating Pickering emulsion with konjac glucomannan (KGM) and κ-carrageenan (CRG). The microstructure revealed that adding the two polysaccharides resulted in Pickering emulsion forming a network structure. It exhibited a denser and more uniform network structure, enhancing its mechanical properties four times and increasing its water-holding capacity by 20 %. In vitro digestion experiments demonstrated that the release of free fatty acids from the Pickering emulsion gel (4.25 %) was notably lower than that from conventional Pickering emulsion (17.19 %), whereas AST bioaccessibility was remarkably low at 0.003 %. It provided a feasible strategy to regulate the bioaccessibility in Pickering emulsion, which has theoretical significance to guide the current eutrophic diet people.

Biocide physically cross-linked hydrogels based on carrageenan and guanidinium polyampholytes for wound healing applications.

Over last years, hydrogels based on natural polymers have attracted considerable interest as materials for wound healing. Herein, hydrogel films based on kappa-carrageenan and guanidinium polyampholytes were prepared by the in situ physical cross-linking with potassium chloride and borax, respectively. The polyampholytes were obtained by a free radical copolymerization of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride and unsaturated acids. To characterize the composite films, NMR, FTIR, SEM, TGA, XRD, element analysis and tensile test were used. Ampicillin was incorporated into the hydrogels to enhance wound healing potential. The healing-related characteristics, including swelling ratio, drug release and antimicrobial activity, were assessed. The equilibrium swelling ratios were in the range of 3.9-6.5 depending on the polyampholyte composition. According to the in vitro ampicillin release studies, 30-43 % of ampicillin was released from the hydrogels after 5 h at 37 °C and pH 7.4, with drug release being temperature and pH dependent. The ampicillin-loaded films showed a remarkable antimicrobial effect. The inhibition sizes for Escherichia coli and Staphylococcus aureus were 1.10-1.85 and 1.95-2.60 cm, respectively. Although the bi-polymeric hydrogels were thoroughly characterized, with the in vitro study of their biocidal effects carried out in this work, the in vivo drug release assessment needs to be further explored.