Properties Of Sodium Alginate Research Articles

Development of sodium alginate-based antioxidant and antibacterial bioactive films added with IRMOF-3/Carvacrol

The purpose of this study was to compare the effects of different concentrations of the amine-functionalized isoreticular metal-organic framework-3 loaded with carvacrol (IRMOF-3/CA) on the properties of sodium alginate (SA) composite films, thus determining the optimal addition amount and further preparing bioactive packaging film with antibacterial and antioxidant activities. The morphology, structure, physical properties, antioxidant and antibacterial activities of the films were characterized and analyzed. The results showed that the thermal stability and light barrier property of the films were improved by the addition of IRMOF-3/CA. When the additional concentration was 0.4 wt%, the tensile, water vapor barrier and hydrophobic properties of the films were increased by 30.13%, 9.06% and 46.43% respectively compared with those of pure SA film. Moreover, the film added with IRMOF-3/CA had sustained antioxidant and antibacterial activities, and had an apparent fresh-keeping effect on pork, suggesting its application potential in food packaging.

Characterization of Sodium Alginate Membrane Plasticized by Polyols and Polyamine for DMFC Applications

This study reports the effect of plasticizers namely isopropanol, polyethylene glycol, maltitol and spermidine on the properties of the sodium alginate composite membrane. The concentration of each potential plasticizer was set at minimum to execute performance. Properties of sodium alginate were studied through characterization studies - Field Emission Scanning Electron Microscope (FESEM) to observe on the morphology structure. The membrane performance is also seen through water uptake and swelling ratio tests. Isopropanol produced better plasticizer with the lowest water uptake of 575.53% and less hydrophilic compared to spermidine (1268.46%), polyethylene glycol (1014.30%) and maltitol (595.82%). Further study may require copolymerization to support polyol for ensuring structure firmness. This study proven the plasticizers could enhance membrane’s flexibility in DMFC and becoming a promising choice of additives for better alginate-based membrane establishment.

Effects of cold-renneted and pre-heated milk protein concentrates (MPCs) addition on the properties of alginate composite gels

This study investigated the effects of milk protein concentrate (MPC85) (untreated, cold-renneted, and pre-heated (80 °C, 30 min)) addition on the physical/mechanical properties of sodium alginate (2% w/w) composite gels in millimeter-size (bead) and centrimeter-size gel forms. The gels were characterized for the degree of syneresis, swelling behavior, hardness, stiffness, viscoelastic behavior, and surface morphology of freeze-dried gel. The results showed that the addition of untreated and treated MPCs reduced the hardness, the stiffness and the solid-like behavior of the alginate gels. Untreated MPC and pre-heated MPC caused no effect on syneresis of alginate gels. The addition of cold-renneted MPC reduced the degree of syneresis in composite gels by 13.7%. Similarly, the addition of cold-renneted MPC reduced (by 16.4%) the degree of syneresis of the alginate composite gels after incubation in simulated gastric fluid (SGF). After incubation in simulated intestinal fluid (SIF), the gel containing alginate only swelled while gels containing untreated MPC and pre-heated MPC experienced degradation and a severe mass loss. Meanwhile, the gels containing cold-renneted MPC swelled and at the same time eroded. Moreover, only cold-renneted MPC composite gels showed lower shrinkage and wrinkles on the surface of the beads during lyophilization. Therefore, based on these results, it is indicated that cold-rennet induced gelation method could increase the effectiveness of MPC as a composite material for alginate gels.

Hydrogels as Durable Anti-Icing Coatings Inhibit and Delay Ice Nucleation

The accumulation of ice on surfaces brings dangerous and costly problems to our daily life. Thus, it would be desirable to design anti-icing coatings for various surfaces. We report a durable anti-icing coating based on mussel-inspired chemistry, which is enabled via fabricating a liquid water layer, achieved by modifying solid substrates with the highly water absorbing property of sodium alginate. Dopamine, the main component of the mussel adhesive protein, is introduced to anchor the sodium alginate in order to render the coating applicable to all types of solid surfaces. Simultaneously, it serves as the cross-linking agent for sodium alginate; thus, the cross-linking degree of the coatings could be easily varied. The non-freezable and freezable water in the coatings with different cross-link degrees all remain liquid-like at subzero conditions and synergistically fulfill the aim of decreasing the temperature of ice nucleation. These anti-icing coatings display excellent stability even under harsh conditions. Furthermore, these coatings can be applied to almost all types of solid surfaces and have great promise in practical applications.

Characterization and properties of sodium alginate from brown algae used as an ecofriendly superabsorbent

Sodium alginate obtained from the extraction of brown algae is used as the backbone for the synthesis of superabsorbent nanocomposite copolymerization. The first stage of extraction is the demineralization process using 0.1 M HCl solution and then 2% Na2CO3 solution for 2 hours at 60°C. The rendement of sodium alginate obtained was 44.32% with molecular weight of 40680 g/mol with measurement of the intrinsic viscosity. FTIR spectra of sodium alginate showed mannuronic acid functional group at wavenumber 884 cm-1 and the uronic acid at wavenumber 939 cm-1, OH functional group at wavenumber 3200-3400 cm-1, and CH2 stretching at wavenumber 2928 cm-1. The diffraction pattern of isolated sodium alginate has specific 2θ at 13.068 and 21.096, amorphous intensity found specific 2θ at 18.058, and the obtained crystallinity degree of the sodium alginate is equal to 29.292% from the XRD analysis. The morphological analysis by SEM shows fibrils of isolated sodium alginate. The success isolation of sodium alginate from brown algae is supported by DSC which shows the decomposition temperature of pure sodium alginate and isolated alginate have close values, namely 251.12°C for pure sodium alginate and 229.90°C for isolated sodium alginate.

Development and Evaluation of Celecoxib Core in Cup Tablets for Pulsatile Drug Delivery

Chronopharmaceutics, the drug delivery based on circadian rhythm is recently gaining much attention worldwide. Keeping an objective celecoxib pulsatile core-in-cup tablet was designed to deliver a rapid or transient and quantified drug after a predetermined lag period. Celecoxib core tablet was prepared by direct compression method and is used to prepare a set of core-in-cup tablets with swellable and rupturable polymers with different proportions with impermeable cup ethyl cellulose. Tablets were evaluated for precompression, postcompression and in vitro dissolution. The drug polymer interaction was studied by FTIR. The precompression data of core/core-in-cup tablet were within the acceptable limit and they can be compressed directly into tablets. The hardness, friability and uniformity in weight and disintegration time results were in accordance with the standard limit. The lag time is dependents on rupturing property of ehtyl cellulose and swelling property polymers. In all the formulations the best fit model was found to be peppas with exponential n value is > 1 indicates the drug release follows super case II transport mechanism. The initial burst release was observed after lag time and drug release was extended up to 12hr in all formulations. The in vitro drug release studies suggest that core-in-cup tablet prepared with ethyl cellulose and sodium alginate shows higher lag time than that of remaining formulations due to more swelling and delayed rupturing properties of sodium alginate and ethyl cellulose.

THE STUDY OF SORPTION OF THE MILK IONIZED CALCIUM BY SODIUM ALGINATE

The possibility of regulation of defatted cow milk salt composition (fat content– 0,05 %) with the use of sodium alginate as a natural ion-exchanger was studied. Realization of the properties of sodium alginate as to the bounding of calcium ions allows receive the systems on the base of cow milk, stable in time and at the thermal processing. The studies established the influence of technological factors on the sorption of ionized calcium by the solution of complex-creator by sodium alginate. It was established, that the important factors that influence the process are the active acidity and conditions of the process, namely, the phased addition of sorbent that favors the equal speed of process and, as the result, the equal speed of sorption during the whole process. At the same time the study of influence of sorption area and temperature demonstrates that these factors are not determining ones in this process. It was established, that rationalization of parameters of ionized calcium sorption results in the raise of thermal stability of defatted cow milk and the systems on its base. Materials, given in the work, are the base for elaboration and introduction of technology of dessert production (ice-cream, creams, puddings, cocktails and so on), in which composition the colloid stability is provided at the joint use of milk and fruit-berry raw material that can be used in food industry.

Molecular weight distribution, rheological property and structural changes of sodium alginate induced by ultrasound

In this study, the effects of ultrasound with different ultrasonic frequencies on the properties of sodium alginate (ALG) were investigated, which were characterized by the means of the multi-angle laser light scattering photometer analysis (GPC-MALLS), rheological analysis, circular dichroism (CD) spectrometer and scanning electron microscope (SEM). It showed that the molecular weight (Mw) and molecular number (Mn) of the untreated ALG was 1.927×105g/mol and 4.852×104g/mol, respectively. The Mw of the ultrasound treated ALG was gradually increased from 3.50×104g/mol to 7.34×104g/mol while the Mn of ALG was increased and then decreased with the increase of the ultrasonic frequency. The maximum value of Mn was 9.988×104g/mol when the ALG was treated by ultrasound at 40kHz. It indicated that ultrasound could induce ALG degradation and rearrangement. The number of the large molecules and small molecules of ALG was changed by ultrasound. The value of dn/dc suggested that the ultrasound could enhance the stability of ALG. Furthermore, it was found that ALG treated by ultrasound at 50kHz tended to be closer to a Newtonian behavior, while the untreated and treated ALG solutions exhibited pseudoplastic behaviours. Moreover, CD spectra demonstrated that ultrasound could be used to improve the strength of the gel by changing the ratio of M/G, which showed that the minimum ratio of M/G of ALG treated at 135kHz was 1.34. The gel-forming capacity of ALG was correlated with the content of G-blocks. It suggested that ALG treated by ultrasound at 135kHz was stiffer in the process of forming gels. The morphology results indicated that ultrasound treatment of ALG at 135kHz increased its hydrophobic interaction and interfacial activity. This study is important to explore the effect of ultrasound on ALG in improving the physical properties of ALG as food additives, enzyme and drug carriers.

Rheological Property of Sodium Alginate-Agar-Montmorillonite Ternary Solution

The rheological properties of sodium alginate (SA)/agar (AR)/montmorillonite (MMT) solutions were investigated using a rotational viscometer. The dependence of solution apparent viscosity on rotation speed, MMT proportion and solution temperature were researched systematically. Furthermore, the relation of apparent viscosity and micro-structure of the ternary solution was also discussed.

Influence of Zeolite NaA on Thermogravimetric Behavior of Sodium Alginate for the Purpose of Processing Plastic Wastes

Thermogravimetric behavior of sodium alginate with incorporation of zeolite 4A has been studied. The experiments were performed at air flow rate of 30 ml/min, under heating rates of 5 ~ 30 K/min and up to 1250 K. Kinetic parameters for the main degradation phase thus were estimated by using the pseudo first-order assumption. The results have shown that the introduced zeolite as well as its content has obviously affected thermal properties of sodium alginate.

Characterization of β-lactoglobulin–sodium alginate interactions in aqueous solutions: A calorimetry, light scattering, electrophoretic mobility and solubility study

The influence of pH (3–7) on the properties of sodium alginate (NaA), β-lactoglobulin (β-Lg) and their mixtures in aqueous solutions was studied at 30 °C using isothermal titration calorimetry (ITC), dynamic light scattering, turbidity, ζ-potential and soluble protein measurements. The electrical charge of isolated β-Lg went from positive to negative as the pH increased from 3 to 7 with the isoelectric point being around pH 4.8. The electrical charge of isolated sodium alginate was negative at all pH values, but was appreciably lower in magnitude from pH 3 to 4 due to partial protonation of carboxyl groups (p K a≈3.5). Light scattering measurements indicated that isolated sodium alginate was completely soluble from pH 3 to 7, but isolated β-Lg formed large complexes ( d V>200 nm) that scattered light at pH 4 and 5. When β-Lg and sodium alginate were mixed together at pH 3 and 4 they formed large complexes ( d V>1000 nm) due to electrostatic attraction between the oppositely charged molecules. At pH 5, β-Lg and sodium alginate formed fairly soluble complexes due to electrostatic attraction between the anionic polysaccharide and cationic patches on the protein surface. At pH 6 and 7, β-Lg and sodium alginate did not form complexes due to electrostatic repulsion between the similarly charged molecules. The knowledge gained in this study could be used to facilitate the rational design of food ingredients and products with desirable functional properties.

Preparations and properties of sodium alginate formed-in-place membranes

Sodium alginate formed-in-place membranes were formed on a macroporous titanium dioxide membrane substrate at pH 3.3, 6.5, and 10.5. To investigate the rate and the mechanism of the membrane formation, the dependence of the pressure-to-flux ratio, P/J, on time, t, during the formation was evaluated using diagnostic graphs ; (P/J) 2 , (P/J) 1/2 and -ln(P/J) vs. t. The microfiltration properties of the membranes were investigated by determining the permeability, J/P, and the rejection of a protein, bovine serum albumin (BSA), in 1 g/L solutions as a function of the concentration of added KCl. The stability of the membranes was evaluated by comparing the ratio of the resistances of the membranes at the end of the formation, R, after crossflow rinsing, R m , and after crossflow rinsing following the BSA microfiltration experiment, R α . The linearity of the graphs of (P/J) 2 vs. t of the membranes formed in neutral or basic conditions indicated that the membranes were formed by deposition of a layer, or cake, of the polyelectrolyte on the substrate, while the membrane formed at lower pH was initially deposited as a layer followed by a more complex mechanism. Only the membranes formed pH 3.3 were stable to the crossflow water rinse and retained high BSA rejection at high ionic strength. Their permeabilities were about 50% lower than the permeabilities obtained with the membranes formed at higher pH. The BSA rejection results imply that a continuous sodium alginate membrane is present for the membranes formed at pH 3.3 and that membranes retaining a macroporous structure are present for the membranes formed at pH 6.5 and 10.5.

Solution properties of sodium alginate from brown seaweeds living along the coast of Japan. I. "Arame" Eisenia bicylis.

Solution properties of sodium alginate from brown seaweeds living along the coast of Japan. I. "Arame" Eisenia bicylis.