Mixture Of Sodium Alginate Research Articles

Three-dimensional bioprinted materials in alginate-hyaluronic acid complex based hydrogel based bio-ink as absorbents for heavy metal ions removal

Major environmental and health effects arise from the presence of heavy metals in water, including lead (Pb²⁺), mercury (Hg²⁺), chromium (Cr⁶⁺), cadmium (Cd²⁺), and arsenic (As³⁺), which contribute significantly to water pollution and pose severe risks to ecosystems and human health. This study demonstrates the fabrication of 3D printed self-regenerative functional living materials, a fungi, by using mixture of sodium alginate and hyaluronic acid hydrogel as absorbents to remove the heavy metals from the environment. Bioprinting has emerged as a transformative technology for fabricating complex biological constructs. The bioprinting experiments, conducted with optimized parameters, revealed the viscoelastic behavior of the hydrogel, suitable for 3D bioprinting applications. MicroCT analysis indicated that the hydrogel's porosity and structural properties support fungal growth in a controlled three-dimensional setting. Microscopic analyses, including phase contrast microscopy, FESEM, and HRTEM, provided insights into the cellular morphology of the bioprinted constructs. Cell viability was assessed using flow cytometry with FDA and PI staining, showing a significant population of live cells, affirming the biocompatibility of the hydrogel. Additionally, the study explored the hydrogel's potential for heavy metal removal from water samples. Multi-element standard solutions containing Copper(Cu²⁺), Cadmium(Cd²⁺), Nickel(Ni²⁺), Cobalt(Co²⁺), and Ferrous(Fe³⁺) ions at different concentrations were incubated with hydrogel patches embedded with Aspergillus flavus. Atomic absorption spectrophotometry analysis showed rapid initial removal rates of metal ions, with maximum removal efficiency achieved around the 12th hour. Comparisons with a control hydrogel without the fungal strain demonstrated significantly enhanced removal efficiency due to the presence of Aspergillus flavus. This study highlights the dual functionality of sodium alginate with hyaluronic acid -based hydrogels for bioprinting fungi and for environmental remediation of heavy metals, offering promising applications in environmental cleanup.

PH-responsive hydrogel containing curcumin-loaded lipid nanocapsules for oral curcumin’s stability, bioaccessibility and intestinal absorption improvement

A liquid formulation with suitable consistency and sustained release characteristics can improve compliance in users with dysphagia.In the study, we prepared curcumin-loaded lipid nanocapsules (Cur-LNCs) and incorporated it in a mixture of sodium alginate, dextrin, calcium chloride and sodium citrate to form a pH-responsive pre-hydrogel solution (SA-DEX:Cur-LNCs). The SA-DEX:Cur-LNCs exhibited a pH-responsive solution-gel conversion: solubilized at near neutral (pH = 7) and rapidly gelatinized to a strong elastic gel at stomach acid (pH = 2.5). The SA-DEX:Cur-LNCs could effectively improve the thermal and pH stability of Cur, and maintain its antioxidant effect. Interestingly, the bioaccessibility of SA-DEX:Cur-LNCs in gastrointestinal was significantly increased to 37.00% when compared with free Cur. The SA-DEX:Cur-LNCs also significantly improved the small intestinal absorption of Cur, being 16 times higher than that of free Cur. Therefore, incorporating lipid nanocapsule in pH-responsive pre-hydrogel provided a new oral administration platform of hydrophobic bioactive compounds for compliance improvement of users with dysphagia.

Synthesis and characterization of ultra-soft alginate hydrogel mimicking lung tissue

ABSTRACT Alginate hydrogels possess properties analogous to those of the extracellular matrix (ECM). Thus, their mechanical behavior approximates soft tissue, which makes them desirable for the production of tissue-equivalent soft deformable structures. This study aims to determine the synthesis-structure-property relationship for alginate hydrogel with the Young’s modulus in the range of 10°~101 kPa, mimicking to that of human lung tissue. Hydrogels, a 3D polymer network embedded in a water-rich environment. Homogeneous alginate hydrogels are synthesized by a direct mixture of sodium alginate and CaCO3, followed by the addition of D-glucono-δ-lactone (GDL) to initiate in-situ Ca2+ release and gelation. The influence of alginate concentration and molar ratio of the constituent calcium ion to carboxyl group from alginate monomer are evaluated while the Young’s modulus of the hydrogel is carefully controlled within the desired range. FTIR and SEM are used to characterize the influence of synthesis parameters at the molecular and microstructure levels. Tension and compression testing are performed to determine the Young’s modulus of the material. Empirical relations are established between synthesis parameters and the mechanical property. The result of the study will be subsequently used to guide the additive manufacturing of soft deformable structures based on alginate hydrogels.

Investigation of swelling behaviour monolayer and double Layer polysaccharide based composite hydrogels

ABSTRACT In this study, monolayer and double layer (core-shell) composite hydrogel beads with and without hydroxyapatite which have potential applications in drug delivery systems were synthesized, and their swelling behaviours were investigated in different pH mediums. The composite hydrogel beads was prepared by crosslinking sodium alginate and kappa-carrageenan (by using Ca+2 and K+1). Core-shell hydrogel beads were formed by coating monolayer composite hydrogel beads with the mixture of sodium alginate and kappa-carrageenan. The structure of hydrogel beads was characterized by Fourier Transform Infrared Spectrophotometer, Scanning Electron Microscopy and Differential Scanning Calorimetry. The effects of the composite hydrogel beads combination and the concentration of crosslinker on swelling behaviours were investigated. Swelling kinetics data were tested using pseudo-second-order model, and the pseudo-second-order model is estimated as a convenient model to represent the swelling kinetic. The results indicated that swelling behaviours of hydrogel beads changed with composite hydrogel beads combination and concentration of crosslinker.

Cytoprotection in gastroesophageal reflux disease and prospects for the use of cytoprotective agents

The analysis of publications is devoted to the problem of treatment and prevention of gastroesophageal reflux disease with the use of cytoprotectors. Special attention is paid to Gastrotop, the new complex of plant origin. Gastrotop (Еrвоzета S.p.A, San Marino) is a new medication with cytoprotective action, containing Mucosave CG, a standardized complex of polysaccharides from the stems of Indian prickly pear (Opuntia ficus‑indica, 33.5%), leaves of European olive (Olea europaea, 24.0%); a mixture of sodium alginate and salts (sodium alginate — 50 mg, potassium bicarbonate — 10 mg, calcium carbonate — 10 mg), an extract of the leaves of Malva sylvestris L. 50 mg. Its action is aimed at the increasing of protection of esophageal and gastroduodenal mucosa from irritating effects of hydrochloric acid, pepsin, and the detergent effect of bile during reflux by means of formation of a strong mucoadhesive biofilm on the walls of the esophagus. The authors present the results of a randomized, double‑blind, controlled clinical trial evaluating the efficacy and safety of a preparation based on alginate/sodium bicarbonate in combination with extracts obtained from Opuntia ficus indica and Olea europaea related to polyphenols on the dynamics of GERD symptoms. It has been established that Gastrotop is well tolerated and effective in controlling symptoms associated with mild GERD manifestations. The results demonstrated the perspective of administration of a standardized complex of polysaccharides as part of Gastrotop in cases when it’s necessary to cancel antisecretory drugs (in particular, proton pump inhibitors PPIs), for example, before assessing the persistence of Helicobacter pylori infection or for the purpose of monitoring of the eradication effectiveness. The use of cytoprotectors in GERD promotes the reduction of incidence and prevention of possible complications, caused by the long‑term PPIs’ use.

Formulation of encapsulating material for packing ginger essential oil (Zingiber officinale Rosc) in soft capsules

Essential oil encapsulation has great potential applications and valuable development prospects in food, functional food and pharmaceutical industries. This study has shown the results of the chemical composition of ginger essential oil (GEO) (Zingiber officinale Rosc) and the best formula to encapsulate ginger essential oil without heating. The optimal formula was determined based on the parameters including the amount, external diameter, strength, encapsulation efficiency and oil-packed volume of ginger essential oil beadlets. Ginger essential oil was extracted by the steam distillation and its chemical composition was analyzed by GC–MS. The method of creating beadlets was manually carried out by single core droplets extrusion device. The main constituents of ginger essential oil were: eucalyptol 29.66%, camphene 15.33% and α – zingiberene 8.91%. The optimal encapsuling formula was a mixture of sodium alginate of 1.4%, iodine carrageenan of 0.5%, xanthan gum of 0.3% and agar of 0.1%. This formula gives the expected beadlets of ginger essential oil with an average external diameter of 5.3 ± 0.1 cm and the encapsulation efficiency of 33 ± 2.56% after 13 hours of drying at 35°C.

Convenient synthesis of seaweed-derived porous carbon supported Cu-MoO2 composite as high-performance photocatalyst

The development of a simple and convenient method for synthesizing photocatalysts for the degradation of tetracycline remains a great challenge. In this work, a Cu-MoO2@C composite was successfully synthesized by a high-temperature carbonization of ammonium molybdate infiltrated copper alginate aerogel, which was obtained by curing a mixture of sodium alginate and ammonium molybdate using Cu2+ ions. The photocatalytic properties of the prepared composites were evaluated by the degradation of tetracycline. The results showed that the introduction of Cu nanoparticles on the MoO2@C hybrid could significantly improve the catalytic performance, and the degradation rate of tetracycline reached 92.48 % after 60 min light exposure. Tetracycline's estimated photodegradation rate constant, which was 0.04013 min−1, was 5 times more than that of the composite without Cu loading. Furthermore, the reaction mechanism was explored by electron spin resonance (ESR) test and free radical capture reagent. Intermediate products of tetracycline degradation were analyzed by liquid mass spectrometry (LC-MS).

Phase Behavior of Aqueous Mixtures of Sodium Alginate with Fish Gelatin: Effects of pH and Ionic Strength.

The phase behavior of aqueous mixtures of fish gelatin (FG) and sodium alginate (SA) and complex coacervation phenomena depending on pH, ionic strength, and cation type (Na+, Ca2+) were studied by turbidimetric acid titration, UV spectrophotometry, dynamic light scattering, transmission electron microscopy and scanning electron microscopy for different mass ratios of sodium alginate and gelatin (Z = 0.01-1.00). The boundary pH values determining the formation and dissociation of SA-FG complexes were measured, and we found that the formation of soluble SA-FG complexes occurs in the transition from neutral (pHc) to acidic (pHφ1) conditions. Insoluble complexes formed below pHφ1 separate into distinct phases, and the phenomenon of complex coacervation is thus observed. Formation of the highest number of insoluble SA-FG complexes, based on the value of the absorption maximum, is observed at рHopt and results from strong electrostatic interactions. Then, visible aggregation occurs, and dissociation of the complexes is observed when the next boundary, pHφ2, is reached. As Z increases in the range of SA-FG mass ratios from 0.01 to 1.00, the boundary values of рНc, рHφ1, рHopt, and рHφ2 become more acidic, shifting from 7.0 to 4.6, from 6.8 to 4.3, from 6.6 to 2.8, and from 6.0 to 2.7, respectively. An increase in ionic strength leads to suppression of the electrostatic interaction between the FG and SA molecules, and no complex coacervation is observed at NaCl and CaCl2 concentrations of 50 to 200 mM.

Application of heat-activated peroxydisulfate process for the chemical cleaning of fouled ultrafiltration membranes

NaClO has been widely used to restore membrane flux in practical membrane cleaning processes, which would induce the formation of toxic halogenated byproducts. In this study, we proposed a novel heat-activated peroxydisulfate (heat/PDS) process to clean the membrane fouling derived from humic acid (HA). The results show that the combination of heat and PDS can achieve almost 100% recovery of permeate flux after soaking the HA-fouled membrane in 1 mmol/L PDS solution at 50 °C for 2 h, which is attributed to the changes of HA structure and enhanced detachment of foulants from membranes. The properties of different treated membranes are characterized by scanning electron microscopy (SEM), atomic force microscope (AFM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS), demonstrating that the reversible and irreversible foulants could be effectively removed by heat/PDS cleaning. The filtration process and fouling mechanism of the cleaned membrane were close to that of the virgin membrane, illustrating the good reusability of the cleaned membrane. Additionally, heat/PDS which can avoid the generation of halogenated byproducts shows comparable performance to NaClO on membrane cleaning and high performance for the removal of fouling caused by sodium alginate (SA), HA-bovine serum albumin (BSA)-SA mixture and algae, further suggesting that heat/PDS would be a potential alternative for membrane cleaning in practical application.

In situ derived sulfated/sulfonated carbon nanogels with multi-protective effects against influenza a virus

Pandemic of H1N1 infections are frequently reported around the world. Despite the availability of influenza remedies, the high tendency for influenza virus to mutate can lead to the emergence of drug-resistant strains. Additionally, the adverse effects of current anti-flu drugs have led some countries to implement restrictions on to use. In response to the urgent demand to explore and design novel antivirals, we have developed a potent alginate (Alg)-derived anti-flu material, from seaweeds. The preparation involves a one-step pyrolytic reaction of a mixture of sodium alginate and ammonium sulfite (AS), which forms carbonized nanogels (CNGs). We have characterized the chemical and physical properties of these Alg@AS CNGs, validated the anti-flu activity in vitro and in vivo, and explored the underlying mechanism. Our results indicate that the Alg@AS CNGs possess abundant sulfite/sulfate surface moieties, exhibit high biocompatibility and remarkable viral suppression properties against H1N1. The viral suppression of Alg@AS CNGs was found to be superior to other sulfated polysaccharides, such as fucoidan, carrageenan, and chondroitin sulfate. The administration of Alg@AS CNGs to H1N1-infected cells and mice resulted in higher cellular viabilities and mouse survival rates, respectively. Improved pathological indices were observed in lung sections, which showed substantially reduced gene expression of inflammatory mediators in tissues upon Alg@AS CNG treatment. We further showed that the Alg@AS CNGs could inhibit H1N1 infection by binding to viral particles and lowering the oxidative stress in cells. In summary, Alg@AS CNGs that were developed in this study were shown to exhibit potential anti-flu activity that protected animals from this lethal health challenge. These findings show that Alg@AS CNGs could be a potential candidate for future pharmaceutical development as an influenza remedy.

Nanoparticle Shape Effect on a Sodium–Alginate Based Cu–Nanofluid under a Transverse Magnetic Field

Sodium-alginate (SA) based nanofluids represent a new generation of fluids with improved performances in terms of heat transfer. This work examines the influence of the nanoparticle shape on a non–Newtonian viscoplastic Cu–nanofluid pertaining to this category. In particular, a stretching/shrinking sheet subjected to a transverse magnetic field is considered. The proposed Cu–nanofluid consists of four different nanoparticles having different shapes, namely bricks, cylinders, platelets, and blades dispersed in a mixture of sodium alginate with Prandtl number Pr = 6.45. Suitable similarity transformations are employed to reduce non–linear PDEs into a system of ODEs and these equations and related boundary conditions are solved numerically by means of a Runge–Kutta–Fehlberg (RKF) method. Moreover, analytical solutions are obtained through the application of a MAPLE built–in differential equation solver (Dsolve). The behavior of prominent parameters against velocity and temperature is analyzed. It is found that the temperature increases for all shapes of nanoparticles with the viscoplastic parameter and the Eckert number.

Regulation on gel textures of Nicandra physalodes (Linn.) Gaertn. pectin by its synergistic interaction with sodium alginate

Synergism between different types of polysaccharides is important to imparting textural preferences and decreasing product costs. In this study, Nicandra physalodes (Linn.) Gaertn. pectin (NPGP) was found to synergistically interact with sodium alginate (SA) under an acidification process by glucono-δ-lactone (GDL) addition. This synergistic interaction led to the formation of much stronger NPGP/SA mixed gels than the pure NPGP and SA gels. During the acidification process, the pH values corresponding to the onset of the synergistic gelation slightly varied depending on NPGP to SA mixing ratios, but in all systems, the synergistic gelation was initiated at pH < 3.6, indicating that sufficient electrostatic suppression on NPGP and SA chains is required for the synergistic gelation. To this end, the addition of a small amount of Na + (0.1%, w/v ) slightly promoted the gelation process. Moreover, the optimum synergistic ratio in the mixed gels was unchanged irrespective of Na + addition, always located at NPGP:SA = 4:6. In order to reveal the network type, theoretical simulations including “iso-strain”, “iso-stress” and “additivity” models were further performed, which suggested that the network structure in mixed NPGP/SA gels is synergistic network rather than phase separated or interpenetrating networks. Further measurements on gel stability suggested that the synergistic NPGP/SA gels showed good freeze-thawing stability, while heating at 80 °C significantly decreased the gel strength, especially at high SA ratios. Overall, these results highlight the potential application of NPGP and SA mixtures in formulations of acidic gel foods. • NPGP can synergistically interact with sodium alginate (SA) under acidic media. • The optimum synergistic ratio between NPGP and SA is 4:6. • Addition of Na + did not change the optimum synergistic ratio. • The network type in the mixed gels was recognized as synergistic network.

Clouding development, interaction, and thermodynamics of triton X-100 + sodium alginate mixture: Impacts of sodium salts and hydrotropic compositions

Here, the clouding development of the triton X-100 (TX-100; an uncharged amphiphile) and a biopolymer, sodium alginate (NaAlg) mixture in aq. solutions of sodium salts and also hydrotropic salt media has been investigated by means of the cloud point (CP) estimation method. The study discloses that the CP value of the mixture of TX-100 + NaAlg is dependent on the composition of Na-based salts and hydrotropic material. In addition, we have compared the impacts of simple sodium salts and hydrotropic sodium salt on the phenomenon of clouding formation. The ΔGc0 values are observed positive in each case, while the positive values are found to be decreased with enhancing salt concentration. The ΔHc0 and ΔSc0 values indicate the persistence of both hydrophobic and exothermic interactions amid TX-100 and NaAlg in the salts and hydrotrope media. Furthermore, this study computes and describes the thermodynamics of transfer and enthalpy-entropy compensation variables.

Preparation and characterization of sodium alginate/gelatin/Ag nanocomposite antibacterial film and its application in the preservation of tangerine

With the increasingly serious problem of environmental pollution caused by non-degradable petroleum-based packaging materials, there is an urgent need to develop an environmentally friendly packaging material. In this study, a food packaging coating with good antibacterial effect was prepared by adding silver nanoparticles (AgNPs) into a mixture of sodium alginate (SA) and gelatin (GL). The film formed by coating (SA/GL/Ag film) has good mechanical properties, and its tensile strength and elongation at break are 46.0 MPa and 17.1 %, respectively. By measuring the hydrophilic properties of the film, it was found that the SA/GL/Ag film has a very low water contact angle (WCA = 40.13°) and good water solubility. By measuring the inhibition zone size of the film against food-borne pathogens, the results showed that SA/GL/Ag film has significant antibacterial activity against both S. aureus and E. coli. Finally, the coating was used for the preservation of tangerines, and it was found that the SA/GL/Ag coating could slow down the loss of nutrients and prolong the shelf life of tangerines. In conclusion, SA/GL/Ag coating (film) has broad application prospects in the field of food packaging.

Bioactive food foams stabilized by licorice extract/whey protein isolate/sodium alginate ternary complexes

Interactions among multi-component food matrices play a key role in modulating the foam properties. In this study, foams containing mixtures of sodium alginate (ALG; 0.5, 1.0, and 1.5% w/v), whey protein isolate (WPI; 0.2 and 0.6% w/v), and licorice extract (LE; 0.1, 0.3, and 0.5% w/v) were formed and characterized. The interactions between the components were confirmed by turbidity, ζ-potential, particle size, Fourier transforms infrared spectroscopy, and sodium dodecyl-sulphate gel electrophoresis. The pre-foam dispersions adopted a shear-thinning behavior with high apparent viscosity as a function of ALG level. Surface tension results indicated that ALG and LE were the main components at the air/water interface, and the pre-foam dispersions possessed a good antioxidant activity (up to 56.53%). The ALG/WPI/LE foamed systems had up to 446.03% overrun, up to 81.69% air-volume fraction, and up to 40.80 h physical stability. Foams with higher overrun and air-volume fraction displayed greater firmness and cohesiveness, as well. Additionally, the elastic properties (Gʹ) were superior to the viscous ones (Gʹʹ) at all frequency range which indicated the solid-like behavior of the foams. A remarkable free radical scavenging activity (up to 49.66%) was also observed in the foams. Therefore, the bioactive foams with high foamability, stability, and viscoelasticity could be used to design novel healthy aerated foods with low calorie content.

Hydration Patterns in Sodium Alginate Polymeric Matrix Tablets-The Result of Drug Substance Incorporation.

The purpose was to show, using destructive/nondestructive methods, that the interplay between water, tablet structure, and composition determine the unique spatiotemporal hydration pattern of polymer-based matrices. The tablets containing a 1:1 w/w mixture of sodium alginate with salicylic acid (ALG/SA) or sodium salicylate (ALG/SNA) were studied using Karl Fischer titration, differential scanning calorimetry, X-ray microtomography, and magnetic resonance imaging. As the principal results, matrix specific features were detected, e.g., “locking” of the internal part of the matrix (ALG/SA); existence of lamellar region associated with detection of free/freezing water (ALG/SA); existence of water penetrating the matrix forming specific region preceding infiltration layer (ALG/SNA); switch in the onset temperature of endothermic water peak associated with an increase in the fraction of non-freezing water weight per dry matrix weight in the infiltration layer (ALG/SNA). The existence of complicated spatiotemporal hydration patterns influenced by matrix composition and molecular properties of constituents has been demonstrated.

THE POTENTIAL OF URONIDE HYDROCOLLOIDS FOR THE FORMATION OF SENSORY CHARACTERISTICS OF HEALTH PRODUCTS FROM HYDROBIONTS

The article presents the theoretical basis and practical aspects of the using of binary compositions of uronid polysaccharides in the technology of culinary products from aquatic organisms in jelly fillings. The relevance of the composition of natural high molecular weight polysaccharides, such as sodium alginate and low-esterified pectin, to promote the improvement of sensory characteristics of culinary products from aquatic organisms in the menu of fish restaurants is shown. The objectives of the study were to obtain a jelly filling of viscous consistency, followed by the formation of a stable, elastic gel for using in the technology of aquatic products. Obtaining a jelly filling involves det-ermining the parameters of the preliminary preparation of hydrocolloids; study of the influence of technological par-ameters on the sensory characteristics of the gel. Creating a dry mixture of sodium alginate and low-esterified pectin with salt and sugar was necessary to ensure the dispersion of particles of dry hydrocolloid powders to prevent sticking when swelling in water at a temperature of 18-20 ° C for 15 minutes. Intense swelling of the mixture occurs in the first 10 minutes of hydration.The degree of swelling reaches 5.8%; further increase in time has almost no effect on the swe-lling process. The swelling kinetics of the hydrocolloid mixture was evaluated by determining the tangent of the angle of inclination tangent to the curve describing the degree of swelling. The rational mass fraction of calcium ions for the formation of a transparent gel of stable, homogeneous, elastic consistency, which is 0.3-0.4% of the 10% solution of calcium chloride, was experimentally established. It was studied that dispersions with a mass fraction of a mixture of alginate: low-esterified pectin substances - 1.8% have a viscous consistency with a dynamic viscosity of less than 0.94 Pa • s, which is important for the implementation of technological operations of transportation and packaging of jelly fillings. The conditions and speed of gelation, which provide the finished culinary products with high sensory cha-racteristics and elastic consistency due to the regulated melting temperature, which is provided by the composition of uronide hydrocolloids, have been studied. It was found that the strength of the gel more than 140 g forms a mixture of hydrocolloids with a mass fraction of from 1.6 to 1.8%.

Investigation of the aggregation, clouding and thermodynamics of the mixture of sodium alginate with sodium dodecyl sulfate and triton X-100 in aqueous and aqua-organic mixed solvents media

Herein, the aggregation, phase separation and binding behavior of sodium alginate (SA) and surfactants (anionic (SDS) and nonionic (TX-100)) mixture in aqueous and aqua-organic mixed solvents have been investigated applying the conductivity, cloud point, and UV–visible spectroscopic methods. In the current study, the various physico-chemical parameters (critical micelle concentration (CMC), extent of bound counter ions, cloud point (CP), binding constant (Kb), thermodynamic properties, and transfer parameters) were determined. The addition of SA facilitates SDS micellization. The CMC of the SA + SDS mixtures were obtained to be dependent on SA concentration, composition of mixed solvents, and temperature. The CMC of the SA + SDS mixture were found to be greater in magnitude in aqua-organic (dimethyl formamide (DMF), acetonitrile (AN), ethylene glycol (EG), and 1,4-dioxane (DX)) mixed solvents than the values observed in H2O medium. The values of counterion binding were found to be enhanced with the boost of concentration of SA and other organic additives. The Kb values of SA + TX-100 mixtures were computed from the Benesi-Hildebrand (BH) plot and the Kb values were found to be temperature-dependent. The CP values of the SA + TX-100 mixture experienced a lessening with growing contents of SA and got enhanced in diols (EG/ propanediol (PrD)) media. The negative values of free energy changes dictate that the micellization of SA + SDS mixture and binding processes for the SA + TX-100 mixture are spontaneous in nature while the positive free energy changes indicate the non-spontaneity of clouding phenomena of SA + TX-100 mixture. The obtained values of enthalpy and entropy changes recommend the presence of hydrophobic, electrostatic, and ion–dipole interactions amongst SA and SDS while hydrogen bonding, ion–dipole, and van der Walls forces are the proposed forces between SA and TX-100. Excellent enthalpy–entropy compensation was observed in each case.

Amylase Production by Aspergillus niger immobilized in Microporous Calcium Alginate Gel Beads

Microporous calcium alginate gel beads were investigated as potential solutions to mass transfer limitations in immobilized cultures. The beads were prepared by gelling mixtures of sodium alginate and fillers (starch or granulated sugars) in calcium chloride solution. The resulting beads were cured in the same solution, during which the fillers leached out of the beads thereby creating micro-pores in the beads (microporous beads). The effectiveness of the microporous beads in improving amylase production by Aspergillus niger LC 269109 was investigated. Spores of A. niger were immobilized in the microporous beads and used for batch alpha amylase and gluco amylase production. Amylase production by the A. niger immobilized in the microporous beads were significantly higher (p&lt;0.01) than the values obtained with the conventional calcium alginate gel beads. Under all the conditions investigated, gluco-amylase activities were significantly (p&lt;0.01) higher than the alpha-amylase activities. Under the optimum conditions of inoculum concentration (1.0 × 105 spores/ml), pH (6), temperature (35°C), bead diameter (3 mm) and calcium chloride concentration (1.5%), the gluco-amylase and alpha amylase activities were 11.98 U/ml and 6.7 U/ml respectively, which were significantly higher (p&lt;0.05) than the 7.8 U/ml and 3.2 U/ml obtained with the conventional gel beads.

Water chestnut, rice, corn starches and sodium alginate. A comparative study on the physicochemical, thermal and morphological characteristics of starches after dry heating

Water chestnut (Trapa bispniosa), rice and corn starch were modified with sodium alginate and subjected to dry heating for 0,2 and 4 h for at 130 °C. The physicochemical, thermal and morphological properties of native as well as modified starches were determined. Thermal and morphological properties were studied using Differential Scanning Calorimeter (DSC) and Scanning Electron Microscopy (SEM). It was observed that the dry heating of starches with and without sodium alginate significantly reduce the swelling power, solubility, paste clarity whereas, water absorption and syneresis increased. The swelling power was higher for corn starch as compared to other starches while rice starch has higher syneresis. In the presence of sodium alginate the water absorption was increased in all starch samples upon heating. The onset temperature was found to be increased after dry heating of all starches. The maximum increased was noticed for rice starch. Morphological studies showed the damaging of granule surface with the accumulation of leached amylose and gum but total degradation was not observed. Peak viscosity, final viscosity, breakdown, and setback of RS- sodium alginate mixture were reduced on dry heating. Although pasting temperature of rice starch was not significantly changed.