Alginate Solution Research Articles

Photochemically induced formation of adhesive hydrogels from sodium alginate, acrylamide, and iron sandwich complexes.

Visible light irradiation of an aqueous solution of sodium alginate and organometallic complex [(C5H5)Fe(toluene)]BF4 transforms it into a rigid hydrogel due to crosslinking of the carboxylate groups by the iron ions. Irradiation of the same iron complex together with K2S2O8 initiates the polymerization of acrylamide, which provides an efficient method for light-controlled one-step preparation of alginate-polyacrylamide double network hydrogels, which are capable of gluing wet glass with 100-200 kPa shear strength.

Влияние сшивающих агентов на матриксные свойства гидрогелевых структур на основе альгината натрия

A comparative study of gelation processes in aqueous solutions of sodium alginate initiated by their chemical crosslinking with divalent ions Ca2+ or Ba2+ was carried out. 3D cryoprinted hydrogel scaffolds of certain architectonics were formed from the studied compositions containing various concentrations of crosslinking agents. It is shown that the increase in the crosslinking agent concentration from 2 to 10 wt. % leads to the improvement in the strength characteristics of alginate structures. At the same time, scaffolds crosslinked with 10 % aqueous solutions of both CaCl2 and BaCl2 retain their structural stability during 21 days of incubation in a culture medium at a temperature of 37 °C. During in vitro experiments on cultures of mesenchymal stem cells derived from rat adipose tissue, samples crosslinked with Ba2+ ions were found to demonstrate a moderate cytotoxic effect and showed their inability to maintain cell adhesion, unlike non-toxic scaffolds crosslinked in CaCl2 aqueous solutions. In vivo analysis of experimental samples on an intramuscular implantation model for male Wistar rats also confirmed moderate cytotoxicity of alginate scaffolds formed using Ba2+ ions as crosslinking agents. The results obtained allow us to assert that of all the studied by us materials, sodium alginate crosslinked with a 10% CaCl2 aqueous solution can be considered the most promising for various biomedical applications.

On the features of breaking a microjet of dilute polymer solution into main and satellite microdroplets under external vibration perturbation

An experimental study of the morphology of the laminar microjet flow of diluted aqueous solutions of sodium alginate without and with the addition of hydroxyethyl cellulose after a nozzle subject to external vibration stimulation by the action of the reverse piezoelectric effect was carried out. We studied the influence of the polymer concentration in the solution (0.5-5 mg/ml), the flow rate of the liquid (4-26 ml/min), and the frequency of the current of external perturbation (0-1.2 kHz) on the capillary crushing of the microjet with a diameter of about 210 um in the range of Ohnesorge numbers from 0.046 to 1.88 and Reynolds numbers 0.7 to 470. The modes of microjet flow and crushing on microdroplets with indication of boundaries of transitions between them are selected, and a general map of modes is built. Taking into account the polymer concentration in the solution, the dependence of the microjet fracture length on its velocity is shown. The conditions of monodisperse microjet destruction with equidistant arrangement of the main microdroplets in the flow are determined, which are related to an optimal balance between the molecular mass of the polymer in the solution, the intensity of external disturbance and the time of stress relaxation in polymer viscoelastic microjets. The role of formation of structures such as "beads-on-filament" in capillary destruction of microjet with identification of cases of absence of occurrence of "satellite" microdroplets from liquid threads between the main microdroplets has been studied. The results are applied to technologies based on in-air microfluidics (bioengineering and additive technologies), dealing with heterogeneous fluids with viscoelastic properties. Keywords: Plateau-Rayleigh instability, reverse piezoelectric effect, monodisperse breakup, relaxation time, microjet flow.

Особенности разрушения микроструи разбавленного полимерного раствора на основные и спутниковые микрокапли под действием внешнего вибрационного воздействия

An experimental study of the morphology of the laminar microjet flow of diluted aqueous solutions of sodium alginate without and with the addition of hydroxyethyl cellulose after a nozzle subject to external vibration stimulation by the action of the reverse piezoelectric effect was carried out. We studied the influence of the polymer concentration in the solution (0.5-5 mg/ml), the flow rate of the liquid (4-26 ml/min), and the frequency of the current of external perturbation (0-1.2 kHz) on the capillary crushing of the microjet with a diameter of about 210 um in the range of Ohnesorge numbers from 0.046 to 1.88 and Reynolds numbers 0.7 to 470. The modes of microjet flow and crushing on microdroplets with indication of boundaries of transitions between them are selected, and a general map of modes is built. Taking into account the polymer concentration in the solution, the dependence of the microjet fracture length on its velocity is shown. The conditions of monodisperse microjet destruction with equidistant arrangement of the main microdroplets in the flow are determined, which are related to an optimal balance between the molecular mass of the polymer in the solution, the intensity of external disturbance and the time of stress relaxation in polymer viscoelastic microjets. The role of formation of structures such as «beads-on-filament» in capillary destruction of microjet with identification of cases of absence of occurrence of «satellite» microdroplets from liquid threads between the main microdroplets has been studied. The results are applied to technologies based on in-air microfluidics (bioengineering and additive technologies), dealing with heterogeneous fluids with viscoelastic properties.

Microfluidic dual picoinjection based encapsulation of hemoglobin in alginate microcapsules reinforced by a poly(L-lysine)-g-poly(ethylene glycol).

Hemoglobin (Hb) encapsulation inside polysaccharide hydrogels has been considered a possible red blood cell (RBC) surrogate in transfusiology. Here we report on the microfluidic dual picoinjection assisted synthesis of Hb encapsulated alginate-poly(L-lysine)-g-poly(ethylene glycol) beads. This process is realized by the on-chip injections of blended Hb alginate solutions in emulsified aqueous calcium chloride (CaCl2) droplets followed by a subsequent injection of an aqueous PLL-g-PEG into each emulsified aqueous droplet. The proposed fabrication approach was realized using a flow-focusing and two picoinjection sites in a single PDMS device. Aqueous CaCl2 solution was emulsified and infused with Hb-alginate solution as the squeezed droplet passed through the first picoinjection site. The injection of PLL-g-PEG to reinforce the microgel and minimize the protein leaching was realized in the second picoinjection site located downstream from the first in the same microfluidic channel. In this process, monodisperse Hb-alginate-PLL-g-PEG particles with a diameter around the size of RBCs (9 μm) were obtained with around 80% of the 7.5 mg ml-1 Hb included in the injected aqueous alginate retaining in the obtained microparticles. Microparticles with Hb loading (32.8 pg per bead) and retention (28.8 pg per bead) over a week of storage at 4 °C are in accordance with the average amount of Hb per RBC. The Hb-alginate-PLL-g-PEG microbeads fabricated in the size range of RBCs are significant for further exploration.

Improving probiotic (Lactobacillus casei) viability by encapsulation in alginate-based microgels: Impact of polymeric and colloidal fillers

Biopolymer microgels (hydrogel beads) can be used to improve probiotic stability during food storage and gastrointestinal passage. In this study, the impact of including natural polymeric and colloidal fillers on the viability of Lactobacillus casei encapsulated in calcium alginate microgels was examined. The polymeric filler was polysaccharides isolated from Choerospondias axillaris fruit peel (CP) and the colloidal filler was oil-in-water emulsion stabilized by CP. Results showed that addition of CP or CP coated lipid droplets significantly increased the antioxidant activity but reduced the apparent viscosity of the alginate solutions. Encapsulation of the probiotics in pure calcium alginate microgels reduced their viability (≈0 log CFU g −1 after 24 h). The inclusion of the polymeric or colloidal fillers within the microgels eliminated this negative effect. Moreover, they enhanced probiotic viability under simulated gastrointestinal tract conditions (>7.0 log CFU g −1 ). The calcium alginate microgels containing CP had the highest probiotic viability (7.42 ± 0.08 log CFU g −1 ) after 20 days storage. Our results indicated that simple calcium alginate microgels are not effective at protecting Lactobacillus casei during storage or gastrointestinal passage. However, incorporation of suitable polymeric or colloidal fillers can significantly enhance their viability. • Microgels were formed by alginate and C. axillaris peel polysaccharides (CP). • Pure calcium alginate microgels encapsulation reduced probiotic viability. • Calcium alginate + CP microgels enhanced probiotic viability during storage. • Adding of CP or CP coated oil droplet improved probiotic gastrointestinal stability.

Alginate Gel Immobilization of Caenorhabditis elegans for Optical Calcium Imaging of Neurons.

A fascinating question in neuroscience is how sensory stimuli evoke calcium dynamics in neurons. Caenorhabditis elegans is one of the most suitable models for optically recording high-throughput calcium spikes at single-cell resolution. However, calcium imaging in C. elegans is challenging due to the difficulties associated with immobilizing the organism. Currently, methods for immobilizing worms include entrapment in a microfluidic channel, anesthesia, or adhesion to a glass slide. We have developed a new method to immobilize worms by trapping them in sodium alginate gel. The sodium alginate solution (5%), polymerized with divalent ions, effectively immobilizes worms in the gel. This technique is especially useful for imaging neuronal calcium dynamics during olfactory stimulation. The highly porous and transparent nature of alginate gel allows the optical recording of cellular calcium oscillations in neurons when briefly exposed to odor stimulation.

Enhanced growth and lipid productivity by living Chlorella sorokiniana immobilized in Ca-alginate beads

The bottleneck for the production of biofuels from microalgae consists on costly harvesting processes and low lipid production, immobilization technology could play a part on making the production of biofuels more feasible. The aim of this study was to evaluate the effect of alginate immobilization on the growth and lipid productivity of the microalgae Chlorella sorokiniana, so far, the main focus of immobilization technology has been its use for wastewater treatment and nutrient removal from effluents. The microalgae Chlorella sorokiniana was cultured in both free and immobilized forms under optimal autotrophic growth conditions. Microalgae were immobilized in calcium alginate beads generated by mixing algal cells with a sodium alginate solution, followed by extrusion into a CaCl2 solution. The results obtained in this study showed that the growth of the microalgae immobilized in alginate beads, was enhanced and achieved a dry cell weight 1.4-fold higher than that of a free cell culture, a higher light transmittance was also achieved in the alginate immobilized culture, and the lipid productivity was increased from 54.21 ± 2.48 mg l−1 d in the free cell culture to 82.22 ± 8.48 mg l−1 d in the immobilized culture. These results demonstrate the effectiveness of immobilization technology for promoting growth and lipid productivity in the microalgae Chlorella sorokiniana.

Effects of Au@Ag core-shell nanostructure with alginate coating on male reproductive system in mice.

Despite the widespread use of silver nanoparticles (NPs), these NPs can accumulate and have toxic effects on various organs. However, the effects of silver nanostructures (Ag-NS) with alginate coating on the male reproductive system have not been studied. Therefore, this study aimed to investigate the impacts of this NS on sperm function and testicular structure. After the synthesis and characterization of Ag-NS, the animals were divided into five groups (n=8), including one control group, two sham groups (received 1.5mg/kg/day alginate solution for 14 and 35 days), and two treatment groups (received Ag-NS at the same dose and time). Following injections, sperm parameters, apoptosis, and autophagy were analyzed by the TUNEL assay and measurement of the mRNA expression of Bax, Bcl-2, caspase-3, LC3, and Beclin-1. Fertilization rate was assessed by in vitro fertilization (IVF), and testicular structure was analyzed using the TUNEL assay and hematoxylin and eosin (H&E) staining. The results showed that the NS was rod-shaped, had a size of about 60nm, and could reduce sperm function and fertility. Gene expression results demonstrated an increase in the apoptotic markers and a decrease in autophagy markers, indicating apoptotic cell death. Moreover, Ag-NS invaded testicular tissues, especially in the chronic phase (35 days), resulting in tissue alteration and epithelium disintegration. The results suggest that sperm parameters and fertility were affected. In addition, NS has negative influences on testicular tissues, causing infertility in men exposed to these NS.

Prodrug-loaded semiconducting polymer hydrogels for deep-tissue sono-immunotherapy of orthotopic glioblastoma.

Although immunotherapy has achieved great success in the treatment of a variety of tumors, its efficacy for glioblastoma (GBM) is still limited. Both the immunosuppressive tumor microenvironment (TME) and poor penetration of immunotherapeutic agents into tumors contributed to the poor anti-glioma immunity. Herein, we develop an injectable prodrug-loaded hydrogel delivery system with sono-activatable properties for sonodynamic therapy (SDT)-triggered immunomodulation for GBM treatment. The prodrug alginate hydrogels (APN), which contain semiconducting polymer nanoparticles (SPNs) and the NLG919 prodrug linked by singlet oxygen (1O2)-cleavable linkers, are in situ formed via coordination of alginate solution with Ca2+ in the TME. SPNs serve as sonosensitizers to produce 1O2 upon ultrasound (US) irradiation for SDT. The generated 1O2 not only induce immunogenic cell death, but also break 1O2-cleavable linkers to precisely activate the NLG919 prodrug. Antitumor immunity is significantly amplified due to the reversal of immunosuppression mediated by indolamine 2,3-dioxygenase-dependent tryptophan metabolism. This smart prodrug hydrogel platform potently inhibits tumor growth in orthotopic glioma-bearing mice. Collectively, this work provides a sono-activatable hydrogel platform for precise sono-immunotherapy against GBM.

Novel Electrospun Polycaprolactone/Calcium Alginate Scaffolds for Skin Tissue Engineering

After decades of research, fully functional skin regeneration is still a challenge. Skin is a multilayered complex organ exhibiting a cascading healing process affected by various mechanisms. Specifically, nutrients, oxygen, and biochemical signals can lead to specific cell behavior, ultimately conducive to the formation of high-quality tissue. This biomolecular exchange can be tuned through scaffold engineering, one of the leading fields in skin substitutes and equivalents. The principal objective of this investigation was the design, fabrication, and evaluation of a new class of three-dimensional fibrous scaffolds consisting of poly(ε-caprolactone) (PCL)/calcium alginate (CA), with the goal to induce keratinocyte differentiation through the action of calcium leaching. Scaffolds fabricated by electrospinning using a PCL/sodium alginate solution were treated by immersion in a calcium chloride solution to replace alginate-linked sodium ions by calcium ions. This treatment not only provided ion replacement, but also induced fiber crosslinking. The scaffold morphology was examined by scanning electron microscopy and systematically assessed by measurements of the pore size and the diameter, alignment, and crosslinking of the fibers. The hydrophilicity of the scaffolds was quantified by contact angle measurements and was correlated to the augmentation of cell attachment in the presence of CA. The in vitro performance of the scaffolds was investigated by seeding and staining fibroblasts and keratinocytes and using differentiation markers to detect the evolution of basal, spinous, and granular keratinocytes. The results of this study illuminate the potential of the PCL/CA scaffolds for tissue engineering and suggest that calcium leaching out from the scaffolds might have contributed to the development of a desirable biological environment for the attachment, proliferation, and differentiation of the main skin cells (i.e., fibroblasts and keratinocytes).

Understanding the microfluidic generation of double emulsion droplets with alginate shell

The monodisperse double emulsions obtained by microfluidic method can serve as ideal templates for preparing core-shell alginate microcapsules, which have attracted much attention in biological applications, such as drug delivery systems and cell encapsulation, tissue engineering. However, the formation behavior and dynamic analysis of double emulsion with an alginate shell is still unclear due to the complex rheological behavior of alginate solutions. Herein, we employ a dual-coaxial microfluidic device to generate the high-quality double emulsion droplets with alginate shell, focusing on the effects of the fluid properties of alginate solution in the middle phase (viscosity, μm) and the fluid flow rate on the droplet formation mechanism. As the viscosity of the middle fluid (μm) increased, the size of compound droplets (D2) increased and the size of inner droplets (D1) decreased, and the break-up regimes occurred a dripping-to-jetting transition when μm = 160 mPa s. The number of encapsulated inner droplets can be predicted and precisely controlled by regulating the generation frequency of inner (f1) and outer droplets (f2). The breakup dynamics of the alginate thread are also analyzed by using the volume-of-fluid/continuum-surface-force (VOF/CSF) method. The results show that the pressure and velocity in the neck of pinch-off is lower in the jetting than that in the dripping regime. This study will provide useful guidance for the rational design and controllable preparation of core-shell alginate microcapsules.

Effect of Cross-linking Time on Sodium Alginate Based Blend Films as a Supporter of Bordeaux Mixture

Blend films based on sodium alginate (SA) are synthesized and the use of these films as a supporter for Bordeaux mixture to adhere the crops for longer time and sustained release of active ingredient were studied. An aqueous solution of Sodium alginate was prepared and the obtained solution was added to bordeaux mixture of fixed compositions. Alginate solution is cross-linked by the multivalent cations present in bordeaux mixture and forms films. Blends based on sodium alginate with gelatin(SAGN) and sodium alginate with guar gum(SAGM) were synthesised. The thickening and cross linking action of these films were controlled by varying the cross linking time. The films were dried at 50oC in an oven and kept in different buffer solutions for swelling studies. From the swelling data, rate and kinetics of swelling were studied and swelling parameters were tabulated. The swelling parameters showed that the various bordeaux mixture cross-linked films were stable and they can absorb sufficient quantity of water and may prevent leaching out of active ingredients on rough weathers. Also the cross-linked polymer film may serve in increasing life and sustained release of active ingredients. Keywords: Blends, Bordeaux mixture, ionic cross linking, pH sensitivity, sustained release

Magnetic chitosan hydrogel beads as adsorbent for copper removal from aqueous solution

Magnetic chitosan hydrogel beads (MCHB) were synthesized by blending chitosan and magnetite (Fe3O4) in sodium alginate solution. The MCHB was used to remove Cu (II) metal ions in an aqueous solution. The performance of MCHB to remove Cu (II) ions was evaluated experimentally at different parameters (the initial pH of the solution, contact time, and various magnetite ratios of the hydrogel beads) in the batch adsorption set-up. This study indicated that MCHB managed to remove Cu (II) ions by adsorption at pH 5 at 24 h of contact time. The hydrogel beads of MCHB-0.5 (C:M:A ratio by weight of 1:0.5:2) show the highest Cu (II) ions removal efficiency of 56.51%. The addition of magnetite at the minimal ratio does not hinder the adsorption of Cu (II) ions onto MCHB. The magnetite in the beads also eases the separation of the hydrogel beads from the solution by an external magnet after treatment.

Alginate based polymeric systems for drug delivery, antibacterial/microbial, and wound dressing applications

Alginates are anionic, hydrophilic polysaccharides that are derived from brown seaweeds and bacteria. The chemical structure contains β-D-mannuronic acid (M) and α-L-guluronic acid (G) and G and M residue segmentation is responsible for the property like gelation and viscosity. The inherent properties like biocompatibility, biodegradability, nontoxicity, high mechanical strength, abundance, and high adsorption capacity have made the alginate-based polymeric systems a promising material in biomedical applications such as drug delivery (controlled/sustained release and tumor therapy), tissue engineering, wound healing, cell encapsulation, and biosensing, etc. Distinctive forms of alginate-based polymeric systems/materials like foams, hydrogels, aerogels, nanocomposites, microspheres, scaffolds, and sponges are being widely explored in biomedical fields. The present review summarizes the sources, extraction/purification methods, properties, and different forms of alginate-based advanced polymeric systems, and their utilization in drug delivery, antibacterial/microbial, and wound dressing applications are thoroughly summarized. The reviewed research work reveals that the alginate-based polymeric systems could be a better candidate for a few of the selected biomedical applications. Moreover, it also reveals that the alginate polymeric systems such as hydrogels, scaffolds, and microspheres are potential candidates in real-time applications when compared to other reported materials. Mainly, alginate polymeric systems available commercially for wound dressing and other applications are still under exploration. In addition, future scopes are employed to highlight existing limitations and solutions of alginates and alginate-based advanced polymeric systems. • Alginates beneficial as potential polymeric system in biomedical applications • Various forms of alginates are comprehensively elucidated • Improved surface properties and important applications are systematically reviewed • Properties can be tuned by combining with other efficient synthetic and natural materials as future advanced polymeric systems

Synthetic seeds technology of Salvia officinalis as a method for short-term storage and in vitro propagation of valuable genotypes

Summary Introduction: The technological advancements in the production of synthetic seeds are critical for the preservation of valuable genotypes of many herbal plants, including Salvia officinalis – sage. Objective: The aim of this study was the production, storage and conversion of artificial sage seeds. The technology of synthetic seeds is placing explants capable of regeneration into plants in a protective casing. Methods: Apical and axillary buds were encapsulated with 1.2% sodium alginate solution, and then dripped in 200 mM CaCl2 solution. Artificial seeds were stored at 4°C for 30 days and then converted on MS medium containing 0.3 mg/l of BAP. Results: The synthetic seeds technology made it possible to obtain a high level of seeds conversion into plants using apical buds (85.0%), and slightly lower in the case of side buds (62.5%). Conclusion: The fully developed technology of synthetic seeds made it possible to obtain a high level of plant viability, which may prove useful for the storage of valuable genotypes of sage.

Mechanical, Barrier, Antioxidant and Antimicrobial Properties of Alginate Films: Effect of Seaweed Powder and Plasma-Activated Water

The incorporation of natural fillers such as seaweed may potentially enhance the properties of biopolymer films. In this study, we investigated the effect of seaweed powder as a bio-filler in alginate-based films at different concentrations (10, 30, and 50%, w/w alginate) and particle sizes (100 and 200 μm) on the mechanical, barrier, antioxidant, and antimicrobial properties of alginate which are essential for food packaging applications. Initially, mechanical properties of the alginate films prepared at different temperatures were evaluated to find the optimal temperature for preparing alginate solution. The addition of seaweed powder did not have any positive effect on the mechanical properties of the alginate films. However, the barrier (water vapor transmission rate) and antioxidant properties were improved with the addition of seaweed filler regardless of concentration. In addition, selected films were prepared in plasma-activated water (PAW). The mechanical properties (tensile strength, but not elongation at break) of the films prepared with PAW improved compared to the films prepared in distilled water, while a significant decrease was observed when incorporated with the seaweed filler. The films prepared in PAW also showed improved barrier properties compared to those prepared in distilled water. The antimicrobial activity of the alginate-seaweed film-forming solution was in general more pronounced when prepared with PAW and stored at 10 °C, particularly at the highest concentration of the film-forming solution (83.3% v/v). A more pronounced inhibitory effect was observed on the Gram-positive S. aureus than on the Gram-negative E. coli, which has been attributed to the different composition and structure of the respective cell walls. This study has demonstrated the potential of seaweed filler in combination with PAW towards enhanced functionality and bioactivity of alginate films for potential food packaging applications.

Green flame-retardant coatings based on iron alginate for polyester fabrics: Thermal stability, flame retardancy and mechanical properties

Polyester (PET) fabrics are widely used in our daily life, but they burn and drip quickly when they encounter flames, and the dripping can cause secondary damage to human bodies. In this study, flame-retardant finishing of PET fabrics was performed by preparing alginate coatings modified with Fe3+. A simple dip-coating technique was used and sodium alginate solution was employed to submerge PET fabrics, after that the coatings were complexed with Fe3+ to endow the flame retardancy of PET fabrics. The micromorphology, mechanical properties, thermal stability, flame retardancy, and burning behaviors of the coated PET fabrics were analyzed. Coated PET fabrics had a limiting oxygen index value of 29%. The vertical flame test illustrated that PET/Iron alginate-2 exhibited excellent self-extinguishing behaviors, no drips appeared. The peak heat release rate of PET/Iron alginate-2 was reduced by 70.3%. In the warp directions, compared with the control, the tensile strength of coated PET textiles increased dramatically. In a word, it is a green method to improve the flame retardancy and anti-dripping of PET fabrics.

Bacterial Cellulose Composites with Polysaccharides Filled with Nanosized Cerium Oxide: Characterization and Cytocompatibility Assessment.

A new biocompatible nanocomposite film material for cell engineering and other biomedical applications has been prepared. It is based on the composition of natural polysaccharides filled with cerium oxide nanoparticles (CeONPs). The preparative procedure consists of successive impregnations of pressed bacterial cellulose (BC) with a sodium alginate (ALG) solution containing nanoparticles of citrate-stabilized cerium oxide and a chitosan (CS) solution. The presence of CeONPs in the polysaccharide composite matrix and the interaction of the nanoparticles with the polymer, confirmed by IR spectroscopy, change the network architecture of the composite. This leads to noticeable changes in a number of properties of the material in comparison with those of the matrix's polysaccharide composition, viz., an increase in mechanical stiffness, a decrease in the degree of planar orientation of BC macrochains, an increase in hydrophilicity, and the shift of the processes of thermo-oxidative destruction of the material to a low-temperature region. The latter effect is considered to be caused by the redox activity of cerium oxide (reversible transitions between the states Ce4+ and Ce3+) in thermally stimulated processes in the nanocomposite films. In the equilibrium swollen state, the material retains a mechanical strength at the level of ~2 MPa. The results of in vitro tests (cultivation of multipotent mesenchymal stem cells) have demonstrated the good biocompatibility of the BC-ALG(CeONP)-CS film as cell proliferation scaffolds.

Effect of Composite Chitosan/Sodium Alginate Gel Coatings on the Quality of Fresh-Cut Purple-Flesh Sweet Potato.

In this study, single-layer coating using chitosan (Ch) and sodium alginate (SA) solutions and their gel coating (ChCSA) formed by layer-by-layer (LbL) electrostatic deposition using calcium chloride (C) as a cross linking agent were prepared to improve storage qualities and shelf-life of fresh-cut purple-flesh sweet potatoes (PFSP). The preservative effects of single-layer coating in comparison with LbL on the quality parameters of fresh-cut PFSP, including color change, weight loss, firmness, microbial analysis, CO2 production, pH, solid content, total anthocyanin content (TAC), and total phenolic content (TPC) were evaluated during 16 days of storage at 5 °C. Uncoated samples were applicable as a control. The result established the effectiveness of coating in reducing microbial proliferation (~2 times), color changes (~3 times), and weight loss (~4 times) with negligible firmness losses after the storage period. In addition, TAC and TPC were better retained in the coated samples than in the uncoated samples. In contrast, quality deterioration was observed in the uncoated fresh cuts, which progressed with storage time. Relatively, gel-coating ChCSA showed superior effects in preserving the quality of fresh-cut PFSP and could be suggested as a commercial method for preserving fresh-cut purple-flesh sweet potato and other similar roots.