Addition Of Alginate Research Articles

Acute effects of different dietary polysaccharides added in milk on food intake, postprandial appetite and glycemic responses in healthy young females

In the present study we compared the postprandial glycemic and satiety responses of different dietary polysaccharides when added in milk (2% M.F.). The objective of this study was to evaluate different polysaccharides against postprandial glucose, appetite responses and food intake at subsequent meal. In a repeated measures design, 30 females (18–30 years) consumed 250 ml milk 2% M.F. (control), or milk with carrageenan (2.5 g), guar gum (2.5 g) and alginate (2.5 g), followed by an ad libitum pizza meal after 120 min. Alginate and guar gum addition resulted in lower caloric intake at subsequent pizza meal. The post-treatment (0–120 min) glucose and average appetite were suppressed by alginate and guar gum (p < 0.0001), with more pronounced effect of guar gum. However, alginate resulted in lower blood glucose (p < 0.0001) compared with control and carrageenan during post-treatment. Alginate and guar gum added beverages would be beneficial in short-term regulation of postprandial glycemia and satiety.

Crosslinking of alginic acid/chitosan matrices using bis phenol-F-diglycidyl ether: mechanical, thermal and water absorption investigation

In this study, blends of alginic acid (AA) and chitosan (Cs) cross-linked with bis phenol-F-diglycidyl ether (BPFDGE) were prepared by solvent evaporation method. Chemical structure was analyzed by FTIR showing the existence of interaction between chitosan and sodium alginate. Three transition temperatures were observed for the AA/Cs/BPFDGE blend system in differential thermo-gravimetric analysis thermograms. The first transition showed weight loss due to elimination of absorbed moisture and second transition was due to cleavage of glycosidic linkage of chitosan and decarboxylation from polysaccharide backbone of alginic acid. In the third transition, decomposition temperature of blends (769 °C) was higher as compared to chitosan (580 °C) and alginic acid (620 °C). Investigation on mechanical properties of blends revealed a decreasing trend due to alginate addition that alters crystallization as well as molecular orientation in AA/Cs blend. Increased water uptake was observed owing to interaction between cationic (chitosan) and anionic (alginic acid) groups.

Effects of Na Alginate in the Porosity of Scaffold Biphasic Calcium Phosphate/Alginate Composites

Biphasic calcium phosphate (BCP) bioceramics containing hydroxyapatite and β-Tricalcium Phosphate phases is one of bone grafting biomaterials that quite often used in bone regeneration due to its best characteristics in biodegradability and stability. Nevertheless, those properties are less enhance the bone ingrowth because of the dense and compact structure. Therefore, one of promising way to improve those properties is fabricating the bioceramics in the form of porous scaffolds. In this research BCP/alginate composite scaffolds were synthesized by using calcined chicken’s eggshells as the calcium donor. The synthesis of BCP/alginate scaffolds was performed by adding Na-alginate into BCP bioceramics as a matrix and porosifier with various percentage wt% of 20%, 30% and 40% using freeze drying processes. X-ray diffraction (XRD) results showed that the addition of alginate tends to decrease the crystallinity of BCP/alginate composites. This XRD result, shown by peaks in 2θ range of 10o-20o, is in accordance with fourier transform infrared spectra showing the characteristics of functional groups of BCP and alginate. Moreover, the obtained mean pore size of samples are in the range of trabecular bone pore size which is about 200-400 μm with highest porosity more than 65% presented by μ-CT scanning analysis. These results indicate that the corresponding composites may suit as ideal bone grafting materials.

Effect of sodium alginate and its guluronic acid/mannuronic acid ratio on the physicochemical properties of high‐amylose cornstarch

To investigate the effect of sodium alginate (AGNa) and its guluronic acid/mannuronic acid (G/M) ratio on the physicochemical properties of high‐AM cornstarch (HACS), the pasting, thermal, rheological, and gelling properties of AGNa‐HACS mixtures were measured by rapid viscosity analysis (RVA), DSC, dynamic rheometry, and texture analysis. Compared with HACS alone, the peak viscosity and final viscosity of AGNa‐HACS were increased by 71–84 RVU and 97–106 RVU, respectively, the breakdown value was reduced by 20 RVU, and ΔH was increased by 2.44–3.31 J/g. The retrogradation rate of HACS after storage for 3–14 days decreased, as well the gel hardness, whereas the apparent viscosity (ηa) and loss tangent (tanδ) increased with the addition of AGNa. The G/M ratio of AGNa influenced the gelatinization, gelling, and retrogradation properties of HACS. The ΔH, storage modulus (G′), and gel hardness were increased by AGNa with a high G content. Short‐term retrogradation was retarded by AGNa with a low G acid content.

Adding neutral or anionic hydrocolloids to dairy proteins under in vitro gastric digestion conditions

The effect of adding uncharged polysaccharides such as konjac glucomannan (KGM) or negatively charged polysaccharides such as alginate to dairy protein ingredients – milk, whey proteins and calcium caseinate – was investigated through simulated in vitro gastric digestion. The apparent viscosity, microstructure (light microscopy), particle size distribution and degradation (SDS-PAGE) of the proteins were monitored after different in vitro gastric digestion times (0, 30, 60 and 120 min). The addition of KGM increased the viscosity values of the samples during gastric digestion, which probably would increase gastric distention affecting satiety. The microstructure and particle size distribution results showed that the aggregates formed in the dairy protein-konjac glucomannan mixtures at the start of gastric digestion were broken down into smaller ones over time. However, the aggregates formed with the addition of alginate were larger and remained almost unchanged throughout gastric digestion, due to the strong interaction between the opposite charges of the protein and alginate. The SDS-PAGE results showed that whey proteins were more resistant to pepsin digestion than caseins and that the alginate slowed down protein degradation. These findings suggest that a combination of whey proteins and alginate could be used to delay gastric emptying and promote satiety.

Modified bacterial cellulose scaffolds for localized doxorubicin release in human colorectal HT-29 cells

Bacterial cellulose (BC) films modified by the in situ method with the addition of alginate (Alg) during the microbial cultivation of Gluconacetobacter hansenii under static conditions increased the loading of doxorubicin by at least three times. Biophysical analysis of BC-Alg films by scanning electron microscopy, thermogravimetry, X-ray diffraction and FTIR showed a highly homogeneous interpenetrated network scaffold without changes in the BC crystalline structure but with an increased amorphous phase. The main molecular interactions determined by FTIR between both biopolymers clearly suggest high compatibility. These results indicate that alginate plays a key role in the biophysical properties of the hybrid BC matrix. BC-Alg scaffold analysis by nitrogen adsorption isotherms revealed by the Brunauer–Emmett–Teller (BET) method an increase in surface area of about 84% and in pore volume of more than 200%. The Barrett–Joyner–Halenda (BJH) model also showed an increase of about 25% in the pore size compared to the BC film.Loading BC-Alg scaffolds with different amounts of doxorubicin decreased the cell viability of HT-29 human colorectal adenocarcinoma cell line compared to the free Dox from around 95–53% after 24h and from 63% to 37% after 48h. Dox kinetic release from the BC-Alg nanocomposite displayed hyperbolic curves related to the different amounts of drug payload and was stable for at least 14 days. The results of the BC-Alg nanocomposites show a promissory potential for anticancer therapies of solid tumors.

Effects of the Addition of Sodium Alginate and the Concentration of Calcium Chloride on the Properties of Composite Nonwoven Fabrics

Nonwoven fabrics have merits, and for example, they can be simply and quickly processed with a variety of materials and an easily changeable manufacturing process. This study aims to examine the influences of the addition of sodium alginate (SA) and the concentration of calcium chloride (CaCl 2 ) on the properties of the composite nonwoven fabrics. Chitosan (CS) micro-particles and SA solution are cross-linked with CaCl 2 with various concentrations, combined with farir heat preservative staples (FT)/cotton (C) nonwoven fabrics, and then freeze-dried to form CS/SA/FT/C composite nonwoven fabrics. Afterwards, physical property tests are performed on the resulting composite nonwoven fabrics to determine their properties as related to various concentrations of CaCl 2 . The addition of SA decreases the water vapor permeability of FT/C nonwoven fabrics by 15 %, but the concentrations of CaCl 2 do not influence the water vapor permeability. Compared to FT/C nonwoven fabrics, CS/SA/FT/C composite nonwoven fabrics have significantly lower water absorbency and water vapor permeability, but a greater stiffness.

Improvement of Bread Making Properties by the Addition of Alginates

Improvement of Bread Making Properties by the Addition of Alginates

Nucleation and Growth of Brushite in the Presence of Alginate

Biomineral formation in vivo is a complex process regulated by functional molecules. Highlighting the mechanisms underlying biomineralization is necessary for a better understanding of in vivo processes and for enhanced in vitro model systems. Here, the effect of alginate and its well-defined oligomers with M- or G-block structure on brushite nucleation and growth is investigated by seeded and unseeded experiments. Growth kinetics were studied by seeded experiments, and it was shown that molecular weight and functionality of alginate additives affect the crystal growth rates and the growth mechanisms. Growth retardation was most prominent when G-block additives were present. Growth proceeded by surface nucleation when alginate and G-block oligomers were added in the crystallization medium, whereas in the presence of M-block oligomers parabolic rate laws were obtained. By decoupling the seeded and unseeded experiments, information was deduced on the effects of additives on brushite nucleation. In the presence of alginate and G-block oligomers, nucleation was inhibited; however, M-blocks did not show a similar effect. Possible modes of interactions between the mineral and polymer additives are discussed by the evaluation of final crystal morphologies.

Influence of Hydrocolloids on Batter Properties and Textural Kinetics of Sponge Cake during Storage

AbstractThe influence of hydrocolloids, including hydroxypropyl methylcellulose (HPMC), xanthan gum (XG) and sodium alginate (AG) at 0.5 and 1.0% (w/w, based on the wheat flour), on batter properties and textural kinetics of sponge cake during storage was studied. It was found that the addition of XG and AG dose‐dependently increased the batter density and the viscosity of all the samples and also decreased the cake specific volume but increased the crumb moisture. The firmness change of sponge cake at different storage temperatures followed a first‐order kinetic reaction, where the activation energy (Ea) decreased in the following order: HPMC &gt; AG &gt; XG, which is in contrast to the firmness change rate constant (k). Addition of 0.5% (w/w) HPMC gave the lowest k (0.1156 day−1) and highest Ea (11.23 kJ/mol) values, reflecting its better firmness retarding property. However, the use of HPMC at 1.0% (w/w) gave an adverse effect.Practical ApplicationsConvenient baked snack foods, such as sponge cakes, are in increasing demand as a result of the changing lifestyles and economics of the global populations. However, the quality of sponge cakes changes (deteriorate) during storage. This study evaluated the use of three different hydrocolloids as potential firmness retarding agents during cake storage. Kinetics measurements were the key parameter used to describe the rate of reaction. Hydrocolloids that help to improve the texture of sponge cake are of a significant interest in the baked goods industry, and such archived research will benefit the industrial cake production for better distribution and marketing of these products.

Sodium alginate decreases the permeability of intestinal mucus

In the small intestine the nature of the environment leads to a highly heterogeneous mucus layer primarily composed of the MUC2 mucin. We set out to investigate whether the soluble dietary fibre sodium alginate could alter the permeability of the mucus layer. The alginate was shown to freely diffuse into the mucus and to have minimal effect on the bulk rheology when added at concentrations below 0.1%. Despite this lack of interaction between the mucin and alginate, the addition of alginate had a marked effect on the diffusion of 500 nm probe particles, which decreased as a function of increasing alginate concentration. Finally, we passed a protein stabilised emulsion through a simulation of oral, gastric and small intestinal digestion. We subsequently showed that the addition of 0.1% alginate to porcine intestinal mucus decreased the diffusion of fluorescently labelled lipid present in the emulsion digesta. This reduction may be sufficient to reduce problems associated with high rates of lipid absorption such as hyperlipidaemia.

Influence of an anionic polysaccharide on the physical and oxidative stability of omega-3 nanoemulsions: Antioxidant effects of alginate

The aim of this study was to assess the impact of an anionic polysaccharide on the physical properties and chemical stability of omega-3 enriched nanoemulsions. Fish oil-in-water nanoemulsions stabilized with a non-ionic surfactant (Tween 80) were mixed with sodium alginate at several concentrations, and then their viscosity, creaming stability, particle size, microstructure, and oxidation were measured. The viscosity of the mixed systems (2.5% w/w of oil) increased with polysaccharide addition, and was primarily governed by the alginate rather than the oil droplets. Droplet flocculation was observed at sodium alginate concentrations exceeding 0.05% (w/w), which led to rapid creaming and an increase in droplet size due to coalescence. This effect was attributed to depletion flocculation arising from the exclusion of non-adsorbed polysaccharide molecules from the immediate vicinity of the droplet surfaces. Nevertheless, the addition of alginate (0.1% w/w) to the nanoemulsions decreased the rate and extent of lipid oxidation during storage. This effect was probably due to the ability of anionic groups on the alginate molecules to chelate pro-oxidant transition metals (such as iron) in the aqueous phase. This study highlights the potential of using alginate as a natural antioxidant in nanoemulsions; however, it also highlights the potential for this polysaccharide to promote physical instability. This information could be used to optimize the composition and structure of food matrices designed to improve the oxidative stability of polyunsaturated lipids.

Effect of the extent and morphology of phase separation on the thermal behavior of co-blending systems based on soy protein isolate/alginate

A series of soy protein isolate (SPI)-based film-forming solutions were prepared by a co-drying process or by direct addition of alginate (ALG), with different degrees of phase separation and morphologies. For a non-phase separation system, a single Tg of the data was well fit by the calculation results of the Couchman–Karasz quotation; moreover, the initial state of SPI/ALG (20:1) and SPI/ALG (10:1) after homogenization and the state of SPI/ALG (20:1) after deposition for 30 min exhibited good uniformity; thus, a single Tg value was also measured in these cases (96.28 °C, 85.37 °C and 112.03 °C respectively). Two Tg values of 74.11 °C and 108.24 °C for SPI/ALG (20:1), 72.86 °C and 110.11 °C for SPI/ALG (10:1) were determined in the 100% of phase separation systems. The mixed interface, SPI-rich phase, and ALG-rich phase of SPI/ALG (10:1) co-blending system after deposition for 30 min were formed, resulting in three different Tg values of 74.32 °C, 90.15 °C and 125.17 °C. The SPI/ALG-CO (20:1) and SPI/ALG-CO (10:1) systems with co-drying process could significantly improve the interface properties and the surface activity of each component. The understanding of Tg led to new insights of defining the limit between the rubbery and glassy states in the film-forming co-blending systems.

Antibacterial silver nanoparticles in polyvinyl alcohol/sodium alginate blend produced by gamma irradiation

Polyvinyl alcohol/sodium alginate/nano silver (PVA/SA/Ag) composite films were made by solution casting method. Gamma irradiation was used to synthesize silver nanoparticles in situ via reduction of silver nitrate without using harmful chemical agents for biomedical applications. UV–vis and XRD results demonstrated that spherical silver nanoparticles were produced even at low irradiation dose of 5kGy. By increasing irradiation dose, more nanoparticles were synthesized while no PVA hydrogel was formed up to 15kGy. Also the size of nanoparticles was reduced with increasing gamma dose evidenced by higher release rate of silver nanoparticles in lukewarm water and SEM images. Comparing SEM images with DLS results indicated good performance of PVA/SA as an efficient stabilizer in preventing agglomeration of the silver nanoparticles. Good miscibility of polyvinyl alcohol and sodium alginate observed on the SEM images was supported with FTIR spectroscopy. Upon addition of sodium alginate to polyvinyl alcohol and increasing silver nanoparticles, the melting peak shifted to lower temperature and crystallinity percent was decreased. Addition of sodium alginate led to remarkable increase in rigidity of PVA. The composites exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli even at very low level of silver nanoparticles.

PLGA/alginate composite microspheres for hydrophilic protein delivery.

Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate.

Novel Thermoreversible Injectable Hydrogel Formulations Based on Sodium Alginate and Poly(N-Isopropylacrylamide)

Novel injectable thermoreversible hydrogel compositions with semi-interpenetrating network structure were prepared through the addition of sodium alginate (SA) to poly(N-isopropylacrylamide) (PNIPAM) aqueous solutions. The addition of the hydrophilic alginate strongly improved the stability against syneresis of the 15 wt% PNIPAM hydrogels formed at 37°C from less than 15 min in the absence of alginate to more than 7 days in the presence of 4 wt% SA. Besides the SA concentration, the hydrogel stability depended on the molecular weight and polydispersity of PNIPAM, being lower when a high molecular weight fraction was present. The phase transition temperature (Tph) of the PNIPAM aqueous solutions decreased with alginate concentration, while the dynamic viscosity and elastic modulus of the hydrogels increased. By decreasing the PNIPAM molecular weight and polydispersity, the dynamic viscosity and elastic modulus of the PNIPAM–alginate hydrogels formed above Tph diminished, while their viscoelastic behavior changed from predominantly elastic to predominantly viscous.

Towards a better understanding on agglomeration mechanisms and thermodynamic properties of TiO2 nanoparticles interacting with natural organic matter

Interaction between engineered nanoparticles and natural organic matter is investigated by measuring the exchanged heat during binding process with isothermal titration calorimetry. TiO2 anatase nanoparticles and alginate are used as engineered nanoparticles and natural organic matter to get an insight into the thermodynamic association properties and mechanisms of adsorption and agglomeration. Changes of enthalpy, entropy and total free energy, reaction stoichiometry and affinity binding constant are determined or calculated at a pH value where the TiO2 nanoparticles surface charge is positive and the alginate exhibits a negative structural charge. Our results indicate that strong TiO2–alginate interactions are essentially entropy driven and enthalpically favorable with exothermic binding reactions. The reaction stoichiometry and entropy gain are also found dependent on the mixing order. Finally correlation is established between the binding enthalpy, the reaction stoichiometry and the zeta potential values determined by electrophoretic mobility measurements. From these results two types of agglomeration mechanisms are proposed depending on the mixing order. Addition of alginate in TiO2 dispersions is found to form agglomerates due to polymer bridging whereas addition of TiO2 in alginate promotes a more individually coating of the nanoparticles.

Characterization and mechanical properties investigation of the cellulose/gypsum composite

We synthesized cellulose/gypsum composites in the presence and absence of sodium alginate and investigated the interaction between the composite components as well as the mechanical properties of the final composites. Four different types of cellulose fiber materials were used: cellulose UFC100, cellulose B400, nanofibrillated cellulose, and Lyocell fiber. For all investigated composites the total amount of admixed cellulose was between 1 and 2 wt%, the amount of admixed sodium alginate was 0.5 wt%. We determined the morphology of the composites and observed that the particle and fiber dimensions of the admixed cellulose affect the mode of gypsum–gypsum interlocking and the total porosity of the composites. This in turn had a substantial influence on the mechanical properties of the final composite materials. The addition of sodium alginate resulted in an increase of ultimate strain values. Composites with Lyocell fiber, a synthetic fiber, also had a high Young’s modulus.

Properties of biodegradable thermoplastic cassava starch/sodium alginate composites prepared from injection molding

Due to poor mechanical properties and high water uptake of biodegradable thermoplastic starch (TPS), in this study, the influence of sodium alginate on properties of biopolymer based on thermoplastic cassava starch (TPCS) was investigated. The TPCS polymer was compounded and shaped using an internal mixer and injection molding machine, respectively. In addition, the TPCS polymer was, then, modified by different contents of sodium alginate, i.e., 0, 10, 20, and 30 wt%. It was found that the TPCS composites showed good phase compatibility between the starch and sodium alginate. In addition, maximum stress, Young's modulus, and hardness of the TPCS composites significantly increased by the addition of sodium alginate. Furthermore, the TPCS composites modified by sodium alginate degraded faster than the neat polymer. Moreover, Fourier transform infrared spectroscopy and thermogravimetric analysis (TGA) were used to characterize the TPCS composites. POLYM. COMPOS., 37:3365–3372, 2016. © 2015 Society of Plastics Engineers

Improvement in bacterial cellulose production using Gluconacetobacter xylinus ATCC 10245 and characterization of the cellulose pellicles produced

Aim This paper deals with the improvement in bacterial cellulose (BC) production by Gluconacetobacter xylinus ATCC 10245 cultivated under shaking condition. Materials and methods The study was performed using two different approaches. First, through the addition of some thickening agents to the fermentation medium; second, by applying a two-stage fermentation process in which cells of G. xylinus were grown under two successive static and shaking conditions. During the first fermentation stage, the experimental microorganism was cultivated under static condition to produce thick, leather-like, white BC pellicles on which the bacterial cells were firmly adhered. However, during the second fermentation stage, these pellicles were reused to inoculate fresh, more economic medium, and incubated under shaking condition. Results The results showed that the addition of sodium alginate at a concentration of 0.4 g/l resulted in a BC production of 8.25 g/l compared with only 1.7 g/l obtained using the control medium without thickeners under similar shaking condition. The second method resulted in a substantial increase in the produced BC pellicle up to about 16.9 g/l. Further increase in the weight of the BC gels was obtained by adopting a repeated batch cultivation method during the second fermentation stage. After seven successive repeated batches, which extended for 56 days, the total BC mass reached 81.25 g/l. The properties of some BC pellicles were studied using thermogravimetric analyses and then compared with those of cotton linter. Conclusion The results showed that these two methods are very promising for BC production on a large scale.