Presence Of Pullulan Research Articles

The selective adsorption mechanism of calcium ions/pullulan in the flotation separation of chalcopyrite from talc

The flotation separation of chalcopyrite from talc by use of pullulan and sodium butyl xanthate (SBX) under calcium ions was investigated in this study. The single mineral flotation shows that SBX collector had a good collecting ability for chalcopyrite while talc had a good natural floatability. The talc flotation was observably depressed while that of chalcopyrite was not affected in the presence of pullulan alone. With the addition of calcium ions. The depression of talc could be achieved with a small amount of pullulan. The artificial chalcopyrite/talc mixture flotation tests reveal that the addition of pullulan could realize the separation of chalcopyrite from talc in the absence and presence of calcium ions, and the dosage of pullulan with calcium ions was lower than that in the absence of calcium ions. Zeta potential measurements suggest pullulan was easily adsorbed onto the calcium ions treated talc surface, and the XPS tests further confirm that calcium ions could selectively adsorb onto the talc surface and increase its activated sites for hydrogen bonding with pullulan molecules. This study is expect to provide a novel polysaccharide depressant for the beneficiation of chalcopyrite from talc.

Preliminary Studies on the In Vitro Interactions Between the Secondary Metabolites Produced by Esca-Associated Fungi and Enological Saccharomyces cerevisiae Strains.

Esca-affected vines alter the carbohydrate metabolism, xylem transport of water and photosynthesis and show regular grapes (but berries do not reach maturity), and phenolic compounds are reduced in concentration, oxidate and polymerizate. Pullulan and a mixture of scytalone and isosclerone (9:1; w/w), secondary metabolites produced in vitro and in planta by Phaeoacremonium minimum (syn. P. aleophilum) and Phaeomoniella chlamydospora, were assayed against the strains Byosal HS1 and IOC 18-2007 in microvinifications with synthetic grape must. The presence of pullulan and pentaketides mix affects the growth and metabolism of the tested Saccharomyces cerevisiae strains. Assays at 100 and 1000 µg mL−1 inhibited the growth of both strains, while no effects were recorded when evaluated at 1 and 5 µg mL−1. In comparison with the controls, pullulan and the scytalone/isosclerone mixture at 10 µg mL−1 had a growth reduction, a lower alcohol yield, reduced the concentration of tartaric acid and malic acid; and slowed down the production of lactic acid, acetic acid and total polyphenol content of the tested S. cerevisiae strains. These metabolites could be applied as an alternative to the sulfite addition in the early stages of vinification to support the action of selected Saccharomyces. Appealing is the subtractive action of pullulan against tartaric acid. Further data are needed to confirm and validate the enological performance in freshly pressed grape juice.

Photocatalytic degradation of selected pharmaceuticals using green fabricated zinc oxide nanoparticles

Heterogeneous photocatalysis is one of the popular alternative treatment methods for wastewater. It utilizes semiconductor material as the catalyst and metal oxide such as zinc oxide nanoparticles (ZnO NPs), emerged as the commonly used catalyst. In this study, a series of biogenic ZnO NPs was fabricated through precipitation method with pullulan as the biomaterial. The amount of zinc salt in the presence of pullulan was varied to study its impact on the generated ZnO NPs. The results showed that without pullulan, the average particle size of ZnO NPs obtained was 110.86 nm. With 0.84 M zinc salt in 50 g/L of pullulan, the ZnO NPs average particle size significantly reduced to 58.13 nm. The surface area of all synthesized ZnO NPs ranging from 14.84 to 19.99 m2 g−1. The photocatalytic activities of all synthesized ZnO NPs were evaluated through the photodegradation of two drugs, amoxicillin (AMX) and paracetamol (PCT). Through the comparison of drugs’ photodegradation with all synthesized ZnO NPs, ZnO NPs produced with 0.67 M zinc salt in 50 g/L of pullulan showed the highest degradation percentage of 85.7% and 96.8% for AMX and PCT respectively. The best photodegradation conditions for the drugs were 30 ppm drugs concentration, pH 9 (for AMX) and pH 5 (for PCT) and 50 mg catalyst dosage. Based on these results, biogenic ZnO NPs has high potential to be used in the treatment of pharmaceutical wastewater.

Photocatalytic degradation of methyl orange using pullulan-mediated porous zinc oxide microflowers.

One of mankind's biggest concerns is water pollution. Textile industry emerged as one of the main contributors with dyes as the main pollutant. Presence of dyes in water is very dangerous due to their toxicity; thus, it is important to remove them from water. In these recent years, heterogeneous advance oxidation process surfaced as a possible dyes' removal technique. This process utilizes semiconductor as photocatalyst to degrade the dyes in presence of light and zinc oxide (ZnO) appears to be a promising photocatalyst for this process. In this study, pullulan, a biopolymer, was used to produce porous ZnO microflowers (ZnO-MFs) through green synthesis via precipitation method. The effects of pullulan's amount on the properties of ZnO-MFs were investigated. The ZnO-MF particle size decreased with the increased of pullulan amount. Interestingly, formation of pores occurred in presence of pullulan. The synthesized ZnO-MFs have the surface area ranging from 6.22 to 25.65 m2 g-1 and pore volume up to 0.1123 cm3 g-1. The ZnO-MF with the highest surface area was chosen for photocatalytic degradation of methyl orange (MO). The highest degradation occurred in 300 min with 150 mg catalyst dosage, 10 ppm initial dye concentration, and pH 7 experimental conditions. However, through comparison of photodegradation of MO with all synthesized ZnO-MFs, 25PZ exhibited the highest degradation rate. This shows that photocatalytic activity is not dependent on surface area alone. Based on these results, ZnO-MF has the potential to be applied in wastewater treatment. However, further improvement is needed to increase its photocatalytic activity.

Effect of Pullulan on Physicochemical, Microbiological, and Sensory Quality of Yogurts.

Pullulan can partially or completely replace starch or fat, thanks to which it can be used for the production of dietetic food. It allows you to maintain the desired consistency, and increases the viscosity of the product. Therefore, an attempt was made to produce yogurts with pullulan addition and determine the effect of its presence on the number of LAB, pH change, titratable acidity, and sensory quality of yogurts during storage at 4°C for 28 days. The effect of addition of 0; 1.0 and 2.0 % w/v pullulan as a yogurt ingredient on the changes in pH, acidity, LAB number, and sensory quality of yogurt during storage at 4°C for 28 days was examined. Pullulan did not affect yogurt pH, but the addition of 2.0 % w/v pullulan increased the acidity of yogurt as compared to that of the control yogurt. A statistically significantly higher total number of Lactobacillus, by approximately 1 logarithmic cycle, was found in yogurts with pullulan than in the control yogurt on the 28th day of storage. The yogurt with 1.0% w/v pullulan addition showed better sensory characteristics than that with 2.0% pullulan w/v addition. The conducted research proved that the presence of pullulan in the culture medium stimulates the growth of selected lactic acid bacteria and influences their fermentation capacity. The use of 1.0 % w/v pullulan during the production of yogurts allowed to obtain a sensorically acceptable product, it had a protective effect on the number of lactic acid bacteria during 28 days of refrigerated storage of yogurt.

Electrospun fibers from blends of pea (Pisum sativum) protein and pullulan

Pea protein isolate (PPI) was evaluated to produce food grade fibers through the electrospinning technique. The presence of pullulan (PUL) and Tween 80 (T) on the spinnability, morphology, physicochemical and mechanical properties were addressed. The presence of PUL in the polymeric aqueous solutions of PPI resulted in decreasing of electrical conductivity and increasing of the viscosity and surface tension. Electrospun mats formed by fiber structures were obtained with PPI:PUL 20:80 and 50:50 containing 20 wt % of Tween 80 (50:50T20) with diameters of 170 and 149 nm, respectively. FTIR data indicated that interactions were present between the hydroxyl groups of pullulan and the amino groups of pea protein and that the presence of Tween 80 favored these interactions. The mechanical properties of the electrospun mats showed that the increase of pullulan in blend increased Young's modulus, maximum stress and strain at rupture.

New cryogels based on polymers and zeolite L for controlled Enalapril maleate release

New composite cryogels for controlled release of Enalapril Maleate (EM) were developed based on two biodegradable polymers, poly(vinyl alcohol) (PVA) and pullulan (PU) as polymer matrix, and zeolite L (ZL) as inorganic filler. The cryogels were prepared by freeze-thaw technique using different concentrations of the components, the EM being introduced directly during the cryogel preparation. The samples were characterized by FTIR spectroscopy, scanning electron microscopy and water vapor sorption-desorption isotherms. The presence of PU and ZL in the cryogels led to the modification of FTIR characteristic absorption bands of EM and contributed to the modification of the cryogel morphology. The sample moisture absorption was in the range 5.28–18.20%, determined at a relative humidity RH = 82%. Cryogels based on PVA, PU and ZL components showed a longer EM release period compared to cryogels containing only PVA. The analysis of in vitro EM release kinetics was performed using three predictable models: zero and first order kinetics, and Korsmeyer-Peppas model. Korsmeyer-Peppas model best fitted the release data.

Addition of Pullulan to Trehalose Glasses Improves the Stability of β-Galactosidase at High Moisture Conditions

Incorporation of therapeutic proteins in a matrix of sugar glass is known to enhance protein stability, yet protection is often lost when exposed to high relative humidity (RH). We hypothesized that especially in these conditions the use of binary glasses of a polysaccharide and disaccharide might yield advantages for protein stability. Therefore, different amounts of the polysaccharide pullulan were introduced in freeze-dried trehalose glasses. In these homogeneous blends, the presence of pullulan above 50 weight % prevented crystallization of trehalose when exposed to high RH. Storage stability testing up to 4 weeks of the model protein β-galactosidase incorporated in pullulan/trehalose blends showed superior behavior of pure trehalose at 30°C/0% RH, while pullulan/trehalose blends yielded the best stability at 30°C/56% RH. In conclusion, binary glasses of pullulan and trehalose may provide excellent stability of proteins under storage conditions that may occur in practice, namely high temperature and high RH.

Development and characterization of food-grade electrospun fibers from amaranth protein and pullulan blends

In this work, novel ultrathin electrospun fibers from different blends of protein isolate (API) and the carbohydrate polymer pullulan, with or without the surfactant Tween 80, have been developed and characterized. The solution properties and molecular organization of the electrospun structures were studied and correlated with the morphology of the obtained fibers. The presence of pullulan in the blends resulted in increased viscosity and lower conductivity of the solutions, related to a better chain entanglement and decrease in the polyelectrolyte protein character, respectively, both factors needed for fiber formation. Infrared spectral changes indicated that defect-free fibers were correlated with extended α-helical protein structures, which for the blends with greater protein contents, were only obtained upon surfactant addition. The thermal stability of the hybrid fibers was better than that of pure API and slightly increased upon surfactant addition, while the water stability of the blends was highly dependent on fiber composition. These structures have a great potential for the encapsulation of bioactives for functional food applications.

Preparation of pullulan-g-poly(L-lysine) and it’s evaluation as a gene carrier

In this study, polypeptide/polysaccharide graft copolymers pullulan-g-poly(L-lysine) (PULPLL) was prepared through the ring opening polymerization of ɛ-benzoxycarbonyl L-lysine N-carboxyanhydrides (Z-L-lysine NCA) in the presence of pullulan. The PULPLL copolymer nanoparticles, which are prepared by the diafiltration method, were investigated by using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectra (1H NMR), dynamic light scattering (DLS), transmission electron microscope (TEM), and fluorescence spectroscopy. The PULPLL copolymers formed self-aggregated nanoparticles in the aqueous milieu. The physicochemical characterization revealed that the nanoparticle size ranged between 60 and 500 nanometers, and the critical aggregation concentration (CAC) is 0.001∼0.1 g/L, depending on the degree of substitution. With negligible cytotoxicity and higher transfection efficiency, PULPLL nanoparticles may be safe gene carriers.

Enhanced tumour-imaging efficacy of 5-aminolevulinic acid complexed with iron oxide nanoparticles

The objective of this study was to prepare the complexes of 5-aminolevulinic acid (5-ALA) and iron oxide nanoparticles with different surface potentials and evaluate the imaging efficiency for mouse melanoma cells (B16 cells). The ferric and ferrous ions were co-precipitated in the presence of pullulan or the cationised and anionised derivatives to prepare iron oxide-pullulan nanoparticles (IOPNs). The surface potential of IOPN was changed by altering the mixing percentage of pullulan derivatives. The 5-ALA was mixed with the IOPN of different surface potentials to obtain IOPN?5-ALA complexes. When incubated with IOPN?5-ALA complexes, B16 cells exhibited the fluorescence of protoporphyrin IX (PpIX) bio-synthesised from 5-ALA internalised. The time profile of PpIX fluorescence percentage was greatly influenced by the surface potential of IOPN. This finding indicates that IOPN is a promising carrier for 5-ALA-based imaging of tumour cells.

Design of iron oxide nanoparticles with different sizes and surface charges for simple and efficient labeling of mesenchymal stem cells

The objective of this study is to prepare iron oxide nanoparticles with different sizes and surface potentials and evaluate the labeling efficiency of bone marrow-derived mesenchymal stem cells (MSC). The ferric and ferrous ions were co-precipitated in the presence of pullulan or the cationized and anionized derivatives to prepare iron oxide-pullulan nanoparticles of a contrast agent of magnetic resonance imaging (MRI). The size and surface potential of iron oxide-pullulan nanoparticles were changed by altering the mixing molar ratio of pullulan OH groups to ferric ions and the mixing percentage of pullulan derivatives, respectively. When MSC were labeled with the iron oxide-pullulan nanoparticles by the co-culture for 1 h, the labeling efficiency and 1H MRI relaxivity were greatly influenced by the particle size and surface potential, while the labeling procedure did not affect the viability and differentiation ability of MSC. These findings indicate that iron oxide-pullulan nanoparticle is a promising tool for the MRI labeling of MSC.

WATER PLASTICIZATION EFFECTS ON CRYSTALLIZATION BEHAVIOR OF LACTOSE IN A CO-LYOPHILIZED AMORPHOUS POLYSACCHARIDE MATRIX AND ITS RELEVANCE TO THE GLASS TRANSITION

ABSTRACT Crystallization of lactose in a co-lyophilized amorphous polysaccharide matrix was investigated under various hydration conditions to test the possible relation between the ability of the polymer to raise the glass transition temperature (Tg) of the lactose-pullulan blend, relative to pure lactose, and the crystallization kinetics. Both calorimetric (DSC) non-isothermal measurements and x-ray diffraction analysis of samples stored at a constant temperature revealed a marked retardation in lactose crystallization in the presence of pullulan; i.e., the rate constant values, as determined by the Avrami analysis, declined and the ‘half-time’ (t1/2c) for lactose crystallization increased with decreasing ratio of lactose/pullulan. The inhibitory action of pullulan on crystallization of lactose could not be solely attributed to Tg-related effects on molecular mobility of the composite systems. At a pullulan weight fraction range of 0.25–0.33 (w/w of total solids) the influence of the polymeric additive on Tg was marginal over the entire water content range examined, although crystallization was delayed as compared with pure lactose. Modeling of the temperature-dependence of t1/2c for the combined lactose-pullulan systems with the Williams-Landel-Ferry (WLF) equation was feasible only when the coefficients C1 and C2 were allowed to vary instead of assuming their ‘universal’ values.

Characterization of novel neopullulanase fromBacillus polymyxa

Bacillus polymyxa CECT 155 produces an extracellular neopullulanase activity that degrades pullulan to panose. This activity was stimulated by the presence of pullulan in the culture, and repressed by glucose. The apparent mol wt determined for the enzyme was 58 kDa. The optimum pH and temperature for neopullulanase activity were pH 6.0 and 50°C, respectively. The enzyme was stable in a pH range of 4.0–8.0, and temperatures up to 60°C. These properties make it suitable for the saccharification processes in the starch industries.

Effect of temperature and viscosity of sieving medium on electrophoretic behavior of sodium dodecyl sulfate-proteins on capillary electrophoresis in presence of pullulan.

Pullulan was used as a sieving medium in high-performance capillary gel electrophoresis to study the effect of temperature and viscosity on electrophoretic behavior of sodium dodecyl sulfate (SDS)-proteins with molecular masses in the range of 14,400-116,000 Da. The migration time decreased with increasing capillary temperature. Equations were derived relating mobility of SDS-proteins to capillary temperature and viscosity of pullulan solution. Linear relationships were obtained from experiments between logarithm of mobility and reciprocal temperature and between double logarithmic values of mobility and viscosity of pullulan solution. The experimental results agree well with the equations.

Purification and general biochemical properties of thermostable pullulanase from Bacillus stearothermophilus G-82.

Thermostable extracellular pullulanase, produced by Bacillus stearothermophilus G-82 was purified to homogeneity from supernatants of continuous culture by ultrafiltration, ammonium sulphate precipitation, chromatography on Sephadex G-100, and DEAE cellulose. A mol wt of 53,000 was determined by gel filtration and 56,000 by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The isoelectric point (pI) was 4.2. The pullulanase contained predominantly acidic amino acids. The enzyme was optimally active at a temperature of 60 degrees C and pH 7.0. It preserved 100% of its activity after 10 min treatment at 60 degrees C. The thermostability was considerably increased in the presence of pullulan. Ca2+ did not increase activity or thermostability. Enzyme activity was fully inhibited by N-bromosuccinimide and partially by phenylmethylsulfonyl fluoride. Bacillus stearothermophilus G-82 pullulanase was able to hydrolyze alpha 1-6 as well as alpha 1-4 glucosidic bonds in pullulan, amylopectin, amylose, glycogen, and dextrin. The enzyme showed highest affinity to pullulan (Km = 0.14).

Interaction of amylose and other α‐glucans with hydrophobic fluorescent probe (2‐p‐toluidinylnaphthalene‐6‐sulfonate)

AbstractFluorescence of 2‐p‐toluidinylnaphthalene‐6‐sulfonate (TNS) was enhanced in the presence of maltooligosaccharides, amylose, and other α‐glucans. The dependence of relative TNS fluorescence intensity per glucose unit on chain length of oligosaccharides was examined. The values of binding constant and thermodynamic parameters, assuming the 1:1 complex for TNS‐amylose (number‐average degree of polymerization, DPN = 17), were determined by the fluorescence titration. The values of thermodynamic parameters for 1:1 complex formation of TNS‐α‐ and β‐cyclodextrins were also determined and compared with those of TNS‐amylose (DPN = 17). The fluorescence intensity of TNS in the presence of amylose (DPN = 600) decreased by the action of glucoamylase and taka‐amylase A. The fluorescence of TNS‐amylose (DPN = 17) system increased with the increased ionic strength. In the presence of pullulan, TNS fluorescence was also enhanced and decreased by the action of pullulanase. Amylopectin enhanced TNS fluorescence rather more strongly than amylose (DPN = 17) at the same concentration. In the presence of dextran, the fluorescence of TNS was scarcely enhanced. The degree of fluorescence enhancement of TNS in the presence of α‐glucans seems to reflect the structures of α‐glucans in solution, since TNS fluorescence is enhanced in the hydrophobic environment or by the disturbance of free intramolecular rotation.