Calcium Alginate Films Research Articles

Improvement of the safety of scallops through the application of calcium alginate films with the controlled release of Vibrio bacteriophage

The increase in the population of antibiotic-resistant bacteria has prompted the exploration of food safety alternatives, such as bacteriophages (phages). This study aimed to develop anti-Vibrio films with controlled phage release and focused on the shelf life extension of scallops. VPy01, a newly isolated lytic phage, demonstrated a rapid bactericidal effect against V. parahaemolyticus in 1 h at a multiplicity of infection of 1. It was stable in a wide range of temperature (-18°C to 60°C), pH (4−11), and salinity (0–6%) conditions. As a genetically secure agent, VPy01 was loaded into a sodium alginate (SA, 2%, w/v) film, and glycerol was used as a plasticizer. It was then cross-linked with various calcium salts (CaCl2, CaCO3, hydroxyapatite, and CaSO4). The SA film cross-linked with CaCl2 (SA-CaCl2) efficiently released VPy01, showing remarkable vibricidal effects (>2-log CFU). The SA-CaCl2 film with well-dispersed phages improved hardness, elongation at break, and oxygen barrier ability. When applied to scallops, the SA-CaCl2 film preserved the hardness and weight of scallops and reduced Vibrio by 1.8-log CFU/scallop. Thus, their shelf life was extended. Overall, this study highlighted the potential of VPy01-loaded calcium alginate films for the extension of scallop shelf life, contributing to sustainability in the seafood industry.

Calcium alginate films loaded with copper-molybdenum oxide nanoparticles for antimicrobial applications

The rise in petroleum-based plastic waste, driven by increased consumption from delivery services and e-commerce, necessitates the search for sustainable alternatives like alginate-based materials to mitigate environmental risks. However, alginate, a biopolymer, has limited physico-chemical properties, lacks antibacterial capacity, and exhibits low antiviral activity. To address these issues, this study synthesized Cu3Mo2O9 semiconductor nanoparticles (CMO) and integrated them into alginate films crosslinked with Ca2+, producing advanced nanocomposite films with varying nanoparticle concentrations (0–10 wt%). CMO nanoparticles release Cu2+ and Mo6+ ions and generate reactive oxygen species (ROS), even in the dark. Results show that CMO weakly interacts with alginate blocks, causing slight structural changes but not significantly altering mechanical or thermal properties. CMO released Cu2+ (150–250 ppb at 24 h) and Mo6+ ions (5–8 ppm at 24 h), with Cu2+ undergoing cation exchange with Ca2+ crosslinking ions. Antibacterial tests demonstrated the composites' effectiveness against Gram-negative Pseudomonas aeruginosa (97.30 % and 91.36 % growth inhibition at 5 % and 10 % CMO), Gram-positive methicillin-resistant Staphylococcus aureus (87.26 % and 96.82 % inhibition at 5 % and 10 % CMO), and Mycobacterium smegmatis (99.83 % and 99.97 % inhibition at 5 % and 10 % CMO). These composites also showed antiviral activity against bacteriophage phi 6 (99.81 % and 92.66 % inactivation at 5 % and 10 % CMO) and bacteriophage MS2 (92.32 % and 92.93 % inactivation at 5 % and 10 % CMO). The primary mechanism is attributed to the release of Cu2+ cations and ROS generation. These nanocomposite films exhibit broad-spectrum antimicrobial activity, offering potential industrial applications in packaging and antimicrobial surfaces.

Investigating a Calcium Alginate-Xylitol Coating Methodology for Controlled Release Profiles of Multivitamin Tablet as a Model Drug

The drug delivery system promotes the release of the active pharmaceutical ingredient (API) to attain the desired therapeutic effect at the time most needed. Alginate is a natural polymer that is frequently employed in drug delivery systems. Calcium alginate can simply coat as a film type on the surface of a tablet, which might be created to be dissolved more quickly and predictably manners in the gastric fluid to deliver as needed in a patient-friendly system. In this study, the sodium alginate solution was reacted with a predetermined calcium compound and xylitol combination, while the multivitamin tablets’ surface was coated with calcium suppliers such as calcium chloride. Then, the coated tablets were subjected to a dissolution test in a simulated gastric fluid. Our study results showed that the sphere formation was excellent in terms of strength and size in 1.0% sodium alginate with 4% calcium chloride. Average sphere sizes were 0.5 ~ 2.0 mm. Their break force was 3.5 N, And the dissolution was the fastest in the coated tablets with 1% sodium alginate and calcium chloride. The dissolution rate was changed proportionally with calcium concentration. A high feasibility of dissolution rate was positively found. When a high concentration of xylitol was mixed with 4% calcium chloride, the dissolution rate was proportional to the concentration of xylitol. In conclusion, the study demonstrated that the dissolution rate of tablets with API might be controllable with the calcium alginate film coating with xylitol.

Alginate-derived solid-liquid hybrid structured adsorbent for CO2 capture

The development of highly stable structured solid amine adsorbent is crucial for the large-scale deployment of CO2 capture systems. Here, we report a structured solid amine adsorbent using the solid-liquid hybrid wrapping method, wherein a suspension of tetraethylenepentamine (TEPA) and ZSM-22 support is encapsulated within a calcium alginate film through freeze-drying. The textural properties of the structured adsorbents (SA@S/TX) were investigated using scanning electron microscopy, N2 adsorption-desorption, Fourier transform infrared spectroscopy, and thermal gravimetric analyzer. The CO2 adsorption capacity of SA@S/TX displayed an initial increase followed by a decrease with increasing TEPA loading, and the adsorption rate exhibited a similar trend according to the pseudo-first-order model. The maximum adsorption capacity and adsorption rate (k) were observed to be 2.22 mmol/g and 0.98 min−1 (under conditions of pure CO2, 1 atm and 25 °C), respectively, at a TEPA content of 0.5. In addition, SA@S/TX exhibited good regeneration stability with a low loss in capacity of 10.8 % during 30 cycle of CO2 adsorption–desorption tests, and high thermal stability with a low amine loss of 2.0 % under conditions of 100 °C and 12 h. These results demonstrate that the solid–liquid hybrid wrapping method effectively shapes the powdered adsorbent while significantly reducing TEPA volatilization, offering a possibility for the industrial applications of solid amine adsorbents.

Experimental Study on Water Retention and Flame Retardancy of Environmental Protection Slurry of Film Coated Gasification Slag

ABSTRACT Grouting Fire Prevention technology is the most commonly used technology in coal mines. In order to improve the water holding capacity of the slurry and prevent the cracking and re-leakage of air caused by the loss of water, this paper used sodium alginate, sodium polyacrylate and gasification slag to prepare thick paste mixture, and then used calcium chloride to induce the gelation of the mixed paste surface to form an elastic solid film. A kind of environmental protection slurry of coated gasification slag (hereinafter referred to as coated slurry) with good environmental protection, high strength and elastic solid film with flame retardant and water retention on the outer surface was developed. In the 30°C-300°C range, when the coated slurry was heated, it would have a significant heat absorption and cooling effect. The results show that the hydrophilic -COO-, -OH in sodium alginate forms a synergistic effect with -COO-, -COOH in sodium polyacrylate, and enhances the water absorption of sodium polyacrylate; The interaction of calcium ions with sodium alginate on the surface of the mixed slurry causes gelation and forms a calcium alginate film on the surface of the coated slurry, which prevents water evaporation.

Development of biodegradable calcium alginate films for packaging applications

Development of biodegradable calcium alginate films for packaging applications

Calcium alginate film with excellent shape memory effect

PurposeSodium alginate (Na-Alg) is a natural polysaccharide with a rich and renewable production that is widely used in the food, pharmaceutical and daily necessities industries, among other fields. The purpose of this study is to obtain a green and degradable shape memory material, calcium alginate (Ca-Alg) film was prepared and the mechanical properties, the shape memory effect of the film were investigated and confirmed.Design/methodology/approachThe Ca-Alg films were prepared by Na-Alg, calcium chloride (CaCl2) solution, and flow extension method. Dissolve sodium alginate powder, remove bubbles, pour into petri dish, dry at 60°C, add calcium chloride solution cross-linking and finally dry naturally. The effect of CaCl2 solution concentration on the mechanical properties of the films were investigated and discussed by universal tensile tester. The shape memory behavior and degradation performance of thin films were verified and studied by the fold-deploy shape memory test and soil embedding method, respectively.FindingsThe Ca-Alg films exhibited good mechanical and shape memory properties, with a 72.2% shape memory fixity ratio and a 92.3% shape memory recovery ratio, respectively. For a period of 120 days, the film treated with a 6 wt% CaCl2 solution degraded at a rate of approximately 53%.Research limitations/implicationsShape memory polymers (SMPs) as intelligent materials are an important research direction for the development of modern high-tech materials. On the other hand, plastic pollution is a major problem today; as a result, preparing green degradable SMPs is essential.Originality/valueThis study synthesized transparent and degradable shape memory Ca-Alg films using Na-Alg and CaCl2 solution and the flow extension method.

Biocompatible Films of Calcium Alginate Inactivate Enveloped Viruses Such as SARS-CoV-2.

The current pandemic is urgently demanding the development of alternative materials capable of inactivating the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus 2019 (COVID-19) disease. Calcium alginate is a crosslinked hydrophilic biopolymer with an immense range of biomedical applications due to its excellent chemical, physical, and biological properties. In this study, the cytotoxicity and antiviral activity of calcium alginate in the form of films were studied. The results showed that these films, prepared by solvent casting and subsequent crosslinking with calcium cations, are biocompatible in human keratinocytes and are capable of inactivating enveloped viruses such as bacteriophage phi 6 with a 1.43-log reduction (94.92% viral inactivation) and SARS-CoV-2 Delta variant with a 1.64-log reduction (96.94% viral inactivation) in virus titers. The antiviral activity of these calcium alginate films can be attributed to its compacted negative charges that may bind to viral envelopes inactivating membrane receptors.

Characterization and in vitro digestibility of potato starch encapsulated in calcium alginate beads

In this study, potato starch granules were encapsulated in calcium alginate beads (PS@CAB) with the aim of slowing starch digestion. The microstructure, gelatinization property, and in vitro digestibility of PS@CAB were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and in vitro simulated digestion experiment. The size of the fresh beads was about 2 mm and reduced to about 1 mm after drying. The encapsulation efficiency of starch was over 98%. Compared to the potato starch, the swelling power of PS20@CA2B decreased from 31.1 ± 0.4 g/g to 6.6 ± 0.4 g/g at 95 °C. DSC results showed that the peak gelatinization temperatures of potato starch encapsulated in the beads increased significantly (p < 0.05) with a maximum value a 69.87 °C, compared with potato starch (62.76 °C). The maximum value of enthalpy change was 11.47 J g−1, which was much higher than that of unencapsulated potato starch (7.56 J g−1). SEM images showed that potato starch granules were coated in beads by calcium alginate films. Moreover, slowly digestible starch and resistant starch contents in the beads increased to 27.5% and 18.3%, respectively, which were remarkably higher than those of potato starch without encapsulation (9.2%, 3.4%, respectively). This study proposes a new strategy for the slow digestion of starch by encapsulating starch granules in calcium alginate beads, which benefits people with type 2 diabetes or obesity.

Evaluating the physical, mechanical and morphological properties of calcium-alginate films coated with sunflower oil or tallow fat

Evaluating the physical, mechanical and morphological properties of calcium-alginate films coated with sunflower oil or tallow fat

Fabrication and characterization of alginate-based films functionalized with nanostructured lipid carriers

This study focuses on the fabrication and characterization of alginate-based films functionalized by incorporating nanostructured lipid carriers (NLCs). The effect of different NLC/alginate mass ratios (R = 0.05, 0.1, 0.2, and 0.35) on the physical, morphological, mechanical, and barrier properties of the calcium-alginate films was evaluated. The addition of the NLCs significantly improved the UV-absorbing properties, without greatly altering their transparent appearance. As the NLC concentration increased, the tensile strength, elastic modulus, and swelling ratio of the films decreased, while their thermal stability, water vapor permeability, and contact angle increased. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images of the films revealed that NLC incorporation led to a more porous internal structure and a rougher surface. Fourier Transform Infrared (FTIR) analysis indicated that there were no new interactions between the calcium-alginate and NLC constituents within the films. Overall, this study shows that NLCs can be successfully incorporated into calcium-alginate films and used to modulate their physicochemical properties. In future, it will be useful to examine the potential of these films to incorporate hydrophobic bioactives such as drugs, nutraceuticals, antimicrobials, antioxidants, and pigments for specific pharmaceutical or food applications.

Enhancement of Antimicrobial Activity of Alginate Films with a Low Amount of Carbon Nanofibers (0.1% w/w)

The World Health Organization has called for new effective and affordable alternative antimicrobial materials for the prevention and treatment of microbial infections. In this regard, calcium alginate has previously been shown to possess antiviral activity against the enveloped double-stranded DNA herpes simplex virus type 1. However, non-enveloped viruses are more resistant to inactivation than enveloped ones. Thus, the viral inhibition capacity of calcium alginate and the effect of adding a low amount of carbon nanofibers (0.1% w/w) were explored here against a non-enveloped double-stranded DNA virus model for the first time. The results of this study showed that neat calcium alginate films partly inactivated this type of non-enveloped virus and that including that extremely low percentage of carbon nanofibers (CNFs) significantly enhanced its antiviral activity. These calcium alginate/CNFs composite materials also showed antibacterial properties against the Gram-positive Staphylococcus aureus bacterial model and no cytotoxic effects in human keratinocyte HaCaT cells. Since alginate-based materials have also shown antiviral activity against four types of enveloped positive-sense single-stranded RNA viruses similar to SARS-CoV-2 in previous studies, these novel calcium alginate/carbon nanofibers composites are promising as broad-spectrum antimicrobial biomaterials for the current COVID-19 pandemic.

Improving the water barrier properties of alginate packaging films by submicron coating with drying linseed oil

AbstractAlginates with excellent film‐forming ability have a promising potential as a safe and biodegradable food packaging material, but as a hydrophilic biopolymer, its general weakness against water has limited its applications. To surpass this weakness, in this study, coating of calcium alginate films with linseed or sunflower oils in micrometric (about 4.55 μm) and submicrometric (about 0.45 μm) thickness was performed, and the characteristics of the films were evaluated. All of the films were homogeneous, transparent and almost colourless. Micro‐coated films presented improved ultraviolet absorbing spectra. The scanning electron microscopy (SEM) images proved the formation of homogeneous and continuous submicron‐coated oil layers for both types of the oils, while some inhomogeneity and defects were observed in the micro‐coated films. Oxidative polymerization of linseed oil was confirmed by Fourier transform infrared (FTIR) spectral analyses. The mechanical strength of the films micro‐coated with linseed oil increased. Submicron coating improved water vapour barrier properties (from 2.20 to 2.92 g/mm/m2/day/kPa) as well as water vapour absorption of the alginate film compared to other films. This result was confirmed by thermogravimetric analyses. The increase in surface hydrophobicity of the films by coating resulted in a significant increase in contact angle (from 46.3° to 89.9° in maximum) and reduction of wettability. The film submicron coated with linseed oil showed the best performance with the least water vapour permeability, water vapour absorption and wettability.

Physical and biological properties of alginate/carbon nanofibers hydrogel films

Alginates are renewable materials with excellent biocompatibility and cost-effectiveness in comparison with other biodegradable polymers. However, these hydrogels have poor mechanical properties that restrict their applications in biomedical fields such as skin tissue engineering. In this regard, the study follows an enhanced engineering route to produce alginate-based films reinforced with different amounts (0, 0.1, 0.5, 1 and 2% w/w) of carbon nanofibers (CNFs) and characterize their physical and biological properties. The results of this study showed that these composites possess similar biological properties to neat alginate hydrogels. Thus, none of the synthesized composite materials were cytotoxic and no cell adhesion was observed on the films. Water sorption at the body temperature did not suffer strong changes with the incorporation of CNFs into the alginate matrix. The dynamic mechanical and tensile/compressive properties of calcium alginate significantly improved with the addition of even a very low amount of CNFs. Thus, the tensile and compression modulus of the calcium alginate films in the dry and hydrated state increases up to three and six times, respectively, with the addition of 2% w/w CNFs. In addition, the composites reinforced with the lowest CNFs content have the advantage of possessing more transparency and lower production costs.

Influence of calcium on white efflorescence formation on dry fermented sausages with co-extruded alginate casings

The effect of the concentration of calcium in the crosslinking solution during co-extrusion of dry fermented sausages with calcium alginate casing on the white efflorescence was investigated. With the co-extrusion technology, a continuous sausage production is possible and, furthermore, snack products with very small calibers can be produced. Therefore, crosslinking solutions with different concentrations of CaCl2 (15, 20, 25, and 30%) were used during the production. High concentrations of calcium led to a very rapid and intensive white efflorescence formation; the efflorescences covered ~90% of the surface of the samples produced with 20–30% of CaCl2 after 8 weeks of storage. However, the batch produced with the lowest amount of CaCl2 showed a slow efflorescence formation and a significantly decreased area covered by it (~70% after 8 weeks). The differences in the formation were attributed to the excess of calcium on the surface of the sausages (saturated calcium alginate film), therefore leading to rapid complexation of lactate to mostly calcium lactate. Whereas with 15% of CaCl2 in the solution, only small amounts of calcium are not bound by the alginate film, and the formation of white efflorescence is due to the time-delayed formation with magnesium, which diffuses from the core to the surface.

Diffusional analysis and textural properties of coated strawberries during osmotic dehydration treatment

BACKGROUND: The use of polysaccharide based edible coatings as a barrier against the solute entry of high caloric constituents, such as sucrose, is a suitable strategy to develop pro-healthy osmo-dehydrated products. OBJECTIVE: This work aims to study the effect of a calcium alginate film over the drying kinetics of strawberries during an osmotic dehydration (OD) treatment at 60°Brix, 4 h, 40°C (sucrose). Also, textural parameters were evaluated. METHODS: It was determined the changes in some selected physical properties, such as: moisture, total solid contents, one-dimensional shrinkage and texture, at 30 min steps during OD treatment. Besides, water and solid diffusion coefficients ( D e W and D e TS , respectively) were calculated by using the analytical solution of Fick’s equation. RESULTS: Diffusion coefficients for water and solids showed significant differences due to coating presence as an evidence of the barrier effect. Coated strawberry samples presented several changes after 2 h of OD treatment at the assayed conditions for most of the parameters evaluated. CONCLUSIONS: Alginate coating at the tested conditions acts as a barrier to sucrose influx and to water outflux until 2 and 3 h of OD treatment, respectively. Besides, a good textural quality for osmotically-dehydrated strawberries was obtained.

Catalytic Reduction of Nitrobenzene Using Silver Nanoparticles Embedded Calcium Alginate Film.

Synthesis of silver nanoparticles embedded on calcium alginate film and the catalytic property of this film in the reduction of nitrobenzene with sodium borohydride are demonstrated in this work. Natural polymer alginate acts as effective reducing and stabilizing agent in synthesis of silver nanoparticles. Effect of different parameters on the preparation of silver nanoparticles, such as, temperature, concentration of silver precursor and heating time was investigated. As-prepared silver nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, UV-Vis spectrometry, and atomic absorption spectrometry. Transmission electron microscopy analysis con-firms the formation of silver nanoparticles with particles size range of 3-19 nm and average particle size was found to be 10±4 nm. Effect of concentration of nitrobenzene and sodium borohydride, catalyst loading and temperature on the catalytic reduction of nitrobenzene was studied. Reusability of catalyst was examined in this reduction reaction and the catalyst shows good activity up to 10th run.

Synthesis and characterization of calcium alginate and cellulose nanocrystal films for lead removal

The contamination of water with lead (Pb) is a society concern since this metal as a toxic cation. Cellulose nanocrystals (CNC) are rod-like structures with variable size, which are prepared by acid hydrolysis of cellulose natural sources, so it is a renewable, biodegradable material, with good mechanical performance. Sodium alginate (SA) is a biopolymer, biodegradable and renewable. This biopolymer can chelate bivalent cations forming gel networks. This work focuses on the combination of these two natural biopolymers to create a film of calcium alginate with CNC with the aim to remove non-essential elements on contaminated water. SA and CNC were mixed forming a dispersion, then they were left to dry and reticulated with sodium chlorate (CaCl2) solution. To determine the adsorption kinetics, the films were put in contact with Pb solution, the mixture was maintained under agitation, at constant speed and temperature, the Pb and calcium (Ca) concentrations in supernatant aliquots were determined using the Inductively Coupled Plasma Optical Emission Spectroscopy (ICP OES) and Flame Atomic Absorption Spectroscopy (FAAS), respectively. The results were applied on three kinetic models of adsorption: pseudo-first order; pseudo-second order and Weber-Morris. Characterizations of films were carried by Fourier Transform Infrared (FTIR); Atomic Force Microscopy (AFM); Scanning Electron Microscopy (SEM). AFM and SEM topography study showed a very flat and smooth surface for the films. The adsorption of Pb onto film increased with time contact. Maximum adsorption of Pb was 3.5 mg per gram of film. The prepared films were characterized by AFM and SEM. FTIR confirmed the structure of both polysaccharides. The Pb adsorption experimental data showed an adjusting for pseudo-second model, agreeing with published papers. Further analysis should be done to evaluate isotherms of adsorption and methods for removing the non-essential elements of the film, with the aim of a possible reuse of it.

Synthesis and characterization of interpenetrating polymeric networks based bio-composite alginate film: A well-designed drug delivery platform.

This study aimed to develop and characterize the calcium alginate films loaded with diclofenac sodium and other hydrophilic polymers with different degrees of cross-linking obtained by external gelation process. To the formed films different physicochemical evaluation were performed which showed an initial character of the films. The films produced by this external gelation process were found thicker (0.031-0.038 mm) and stronger (51.9-52.9 MPa) but less elastic (2.3%) than those non-cross-linked films (0.029 mm; 39.7 MPa; 4.4%). The lower water vapor permeability (WVP) values of the films were obtained where maximum level of crosslinking occurs. Composite films can be cross-linked in presence of external crosslinking agent to improve the quality of the produced matrices for various uses. The characterization of the film was performed using Differential Scanning Calorimetry (DSC) and Fourier-Transform Infrared Spectroscopy (FT-IR) analysis. The Scanning Electron Microscopy (SEM) study showed the morphology of treated composite films. The kinetic release studies showed a sustained release of the drug from the formulated films as it can be prolonged in composite film. The prepared biodegradable Ca-Alginate bio-composite film may be of clinical importance for its therapeutic benefit.

Development of Arbuscular Mycorrhizal Fungi-Organic Fertilizer Pellets Encapsulated with Alginate Film

A novel formulation consisting of arbuscular mycorrhizal fungi (AMF) spores mixed with sterilized organic fertilizer (AMF-F) encapsulated by an insoluble calcium alginate film was developed to enhance AMF efficacy and stability. The hardness of the pellets increased from 7–8 N to approximately 80 N by increasing the alginate concentration of the coating film from 1 to 3%. The AMF spore germination rate for the AMF and AMF-F pellets coated with calcium alginate films depended on the alginate concentration. A 2% sodium alginate formulation for the coating films resulted in optimal AMF spore germination rates and mechanical properties for handling, transport, and stability. The inclusion of a sterilized organic fertilizer in the encapsulated AMF-F pellets considerably induced AMF mycelial growth and helped prolong the shelf life of the pellets. In soil, the AMF-F pellets encapsulated with alginate initially degraded faster than the alginate-encapsulated AMF pellets. However, both types of pellets were fully degraded within 30 days. It was demonstrated that AMF and AMF-F could promote colonization and provided resistance to drought stress in maize potted plants.