Potato Starch In Presence Research Articles

Multi-stimuli-responsive semi-IPN cryogels with native and anionic potato starch entrapped in poly(N,N-dimethylaminoethyl methacrylate) matrix and their potential in drug delivery

This study was focused on the preparation of novel multi-stimuli-responsive semi-interpenetrating polymer networks (semi-IPN) hydrogels by cross-linking polymerization of N,N-dimethylaminoethyl methacrylate (DMAEM) in the presence of potato starch (PS) or anionically modified PS by using ice-templating strategy (−18°C). Cryogelation was used for this aim because it allowed decreasing the monomer concentration to 10wt.% and a very fast response at swelling of the composite gels. Furthermore, the anionically modified PS allowed the decrease of the volume phase transition temperature (VPTT) of the composite cryogels by its electrostatic interactions with the matrix. After the characterization of the composite structure by Fourier transform infrared spectroscopy and of the macroporous morphology by scanning electron microscopy analysis, the effect of the entrapped polysaccharide on the swelling properties of the composite cryogels, and their response at three stimuli (pH, temperature and ion nature and concentration) were deeply investigated. The VPTT of the composite cryogels was situated in the range 36–39°C, the particular value depending on the DMAEM concentration and on the nature and content of polysaccharide. After that, diclofenac sodium (DS), taken as a model acidic drug, was easily loaded into the composite cryogels by the solvent sorption–evaporation strategy due to the interconnected pores of these materials. The controlled delivery of DS from the novel semi-IPN composite cryogels was then optimized by the investigation of the effects of pH, temperature, and cycling changes of the release temperature. It was found that these composite cryogels are promising systems for the sustained delivery of DS in the simulated intestinal fluid, but not in the simulated gastric fluid, and this recommends them as vehicles of drugs in colon. Finally, the release mechanism of DS from the composite cryogels was discussed based on two kinetic models.

English

The use of fertilizer is pivotal to ensure soil fertility. Green fertilizers have many advantages and bio-molecules generated in a bacterial cell that can be used as green fertilizer. To produce bio-molecules from a bacterial cell, a bacterium was isolated that uses natural starch as sole carbon source. The organism was grown in presence of various natural starchy materials. The organism was partially identified as Bacillus sp. The optimum conditions for growth of the strain were: temperature of 37.0°C and pH 7.0. However, it grows well even above 55.0°C. The optimum conditions for degradation of various starchy substrates using extra-cellular amylase of the strain were studied. The optimum pH was 4.0 for soluble starch whereas it was pH 5.0 for other substrates and temperature was 17.0°C for soluble starch and 37.0°C for others. Prolongation of time of incubation, velocity of enzyme reaction, and optimum concentration of various metal ions for amylase activity was also studied using optimum assay conditions. Molecular cloning and expression of amy gene of the strain was done in Escherichia coli DH5α. The host cell harboring the recombinant plasmid was grown in the presence of potato starch and incubated for many days to obtained cellular lysate and the liquid biomass might be used as bio-fertilizer. Key words: Amylolytic bacteria, amylase, bio-molecules, bio-fertilizer, single cell fertilizer.

Highly exfoliated eco-friendly thermoplastic starch (TPS)/poly (lactic acid)(PLA)/clay nanocomposites using unmodified nanoclay

Highly exfoliated, biodegradable thermoplastic starch (TPS)/polylactic acid (PLA)/sodium montmorillonite (NaMMT) nanocomposites were prepared by an eco-friendly approach, involving in-situ gelatinization of potato starch in presence of dispersed nanoclay followed by melt mixing with PLA. The morphological analysis revealed that the NaMMT was selectively dispersed into the TPS in a highly delaminated manner. An increase in mechanical as well as thermomechanical properties was evident in the presence of PLA and more influenced in the presence of clay. The water absorption was significantly decreased in the presence of PLA (∼8%) itself and both PLA and clay (∼8–12%) in the nanocomposites. The improved mechanical properties along with its biodegradability might lead to a new green material in the area of packaging.

Sweeter But Deadlier: Decoupling Size, Charge and Capping Effects in Carbohydrate Coated Bactericidal Silver Nanoparticles

Silver nanoparticles are widely used due to their biomedical-antibacterial applications. At the same time, the stabilization of these nanoparticles is challenging and may be made using polymeric carbohydrates, based on the practice of avoiding toxic chemicals and undesirable residues. In this study, we synthesized silver nanoparticles (AgNPs) which were stabilized by carbohydrates (potato starch and chitosan) and characterized by UV-Vis spectroscopy, zeta potential and transmission electron microscopy techniques. Bactericidal efficiency of AgNPs capped with different carbohydrates was tested demonstrating that the synthesized materials were able to inhibit the growth of two clinical/medical relevant bacteria strains (Escherichia coil and Staphylococcus aureus). AgNPs stabilized by chitosan presented enhanced bactericidal activity if compared to the ones synthesized in presence of potato starch. This difference is mainly attributed to the known antibacterial properties of chitosan associated to overall positive charge of the nanoparticles capped by this polymer. Those nanoparticles obtained in presence of starch presented minor bactericidal effects since the starch-capping agent is not able to contribute to the avoidance of bacteria growth and confers a quasi-neutral charge to the nanoparticle.

Multiresponsive macroporous semi-IPN composite hydrogels based on native or anionically modified potato starch

Macroporous semi-interpenetrating polymer networks (semi-IPN) composite hydrogels were synthesized by cross-linking polymerization of acrylamide (AAm) with N,N’-methylenebisacrylamide (BAAm) in the presence of potato starch (PS) or an anionic polyelectrolyte derived from PS (PA), below the freezing point of the reaction solution (−18°C). The composite cryogels have been further modified by the partial hydrolysis of the amide groups in poly(acrylamide) (PAAm) matrix, under alkaline conditions. The influence of the entrapped polymer on the properties of the composite gels, both before and after the hydrolysis, has been evaluated by the swelling kinetics, FT-IR spectroscopy, scanning electron microscopy, and external stimuli responsiveness. The potential of the anionic composite cryogels as intelligent hydrogels has been evaluated by the investigation of the deswelling/reswelling kinetics as a function of solvent nature, ionic strength, and environment pH. Cryogels with fast responsivity at variation of the external stimuli, which withstood repeated deswelling/reswelling cycles, have been obtained at a low cross-linker ratio (one mole BAAm for 80 moles of AAm) and a monomer concentration around 3wt%.

Influence of water on potato starch–lipid interactions. An electron spin resonance (ESR) probe study

Electron spin resonance (ESR) was used in order to study the mechanism of interaction of potato starch with lipids in systems with different water contents (40, 50 and 60% w/w) during heating and cooling. Different spin probes were used, on the one hand spin-labelled stearic acids (5-DSA and 16-DSA), which limited lipids, and on the other hand the water-soluble probe 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol), which was sensitive to changes in the dynamic properties of the water phase associated with the temperature-induced starch structural transformations. Whatever the water content in the hydration range considered, Tempol was observed to be relatively mobile in the presence of potato starch, whereas a strong absorption of spin-labelled stearic acids on potato starch granules took place at room temperature for all investigated starch–water systems. Spin-labelled stearic acids were expected to stick on the starch granules. The mobility of the spin-labelled stearic acid was less upon cooling than upon heating as a result of starch gelation. The mobility of spin probes decreased with increasing starch concentration. Introduction of a doxyl fragment at position 16 of the hydrocarbon chain leads to a lower degree of immobilisation of the spin probe as compared with 5-DSA. This result suggests that there is a stronger interaction of polar sites of stearic acid with starch granules. © 2000 Society of Chemical Industry

Influence of water on potato starch-lipid interactions. An electron spin resonance (ESR) probe study

Electron spin resonance (ESR) was used in order to study the mechanism of interaction of potato starch with lipids in systems with different water contents (40, 50 and 60% w/w) during heating and cooling. Different spin probes were used, on the one hand spin-labelled stearic acids (5-DSA and 16-DSA), which limited lipids, and on the other hand the water-soluble probe 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol), which was sensitive to changes in the dynamic properties of the water phase associated with the temperature-induced starch structural transformations. Whatever the water content in the hydration range considered, Tempol was observed to be relatively mobile in the presence of potato starch, whereas a strong absorption of spin-labelled stearic acids on potato starch granules took place at room temperature for all investigated starch–water systems. Spin-labelled stearic acids were expected to stick on the starch granules. The mobility of the spin-labelled stearic acid was less upon cooling than upon heating as a result of starch gelation. The mobility of spin probes decreased with increasing starch concentration. Introduction of a doxyl fragment at position 16 of the hydrocarbon chain leads to a lower degree of immobilisation of the spin probe as compared with 5-DSA. This result suggests that there is a stronger interaction of polar sites of stearic acid with starch granules. © 2000 Society of Chemical Industry

Kamaboko Gel-strengthening Effect of Polyuronides and Other Polysaccharides.

The screening test of the kamaboko gel-strengthening effect was made with Na and Ca salts of polyuronides and carboxymethyl cellulose (CMC), in addition to cellulose. It was found that Ca salts of alginic acid, pectic acid, pectinic acid, and CMC increased the breaking force of kamaboko obtained from the surimi of Alaska pollack, whereas their Na salts except Na-pectinate did not. The increase in the breaking force induced by Ca-CMC disappeared by increasing its degree of sub-stitution of hydroxyl groups to carboxymethyl groups. Furthermore, fine particles of cellulose (400 meshes) increased the breaking force and breaking strain, and decreased the expressible water, but were ineffective when the particles became coarser. Under the presence of potato starch, even coarse particles of cellulose were effective. The breaking force was not so increased by increasing the ratio of CaCl2 to NaCl to be added to the surimi.

Solubilization of amobarbital by mechanical treatment in the presence of diluents.

Amobarbital was ball-milled, triturated, mortar-ground or stamp-milled in the absence or in the presence of various kinds of diluents, and the variation of solubility of amobarbital from these samples in the KH2PO4-Na2HPO4 buffer solution of pH of 6.0 at 30°was investigated. It was suggested from the results of the elemental analysis, measurement of the mass spectra and the infrared spectra, and the chemical analysis by thin-layer chromatography and gas chromatography that amobarbital in the mechanically treated mixtures of precipitated silica or carbon black was hydrolyzed by the addition of water. It was also suggested that amobarbital decomposed or formed complex by ball-milling in the presence of potato starch. But, it was considered that decomposition of amobarbital by the mechanical treatment in the absence and in the presence of the other diluents was negligible. Solubility of amobarbital in the buffer solution increased by mechanical treatment in the presence of methyl cellulose or hydroxypropyl cellulose. It was considered that solubilization of amobarbital was related to the decrease in the intensity of the signals of amobarbital in the X-ray diffraction diagrams and dropping of the melting point of amobarbital by mechanical treatment in the presence of the diluent. It was also considered that solubilization of amobarbital was due to the interaction with the diluent in the suspension caused by mechanical treatment and to the kind of the crystal structure of amobarbital formed by recrystalization after dissolution.

Uncatalyzed Polymerization of Methyl Methacrylate in the Presence of Starch

Uncatalyzed polymerization of methyl methacrylate (MMA) in the system of starch-water or starch-water-carbon tetrachloride was carried out in vacuo sealed tube at 40°C for 5 hrs. As the result, both total conversion (T) and yield of homopolymer (H) showed maximum values at 2 vol.% of CCl4. Percentage of grafting (P), graft efficiency and percentage of weight increment (W) of corn starch (CS) were markedly diminished by addition of CCl4. The polymerization of MMA was somewhat hindered by the presence of CS, while it was accelerated by the presence of potato starch (PS) . The (H) value was exclusively increased by addition of the emulsifier. When air was enclosed into the sealed tube and the polymerization was attained, the (P) value, the (W) value and the (H) value were increased by this system compared with vacuo system. Moreover, a small quantity of oxygen in the sealed tube further increased the (P) value. As for the effect of the kind of starch on the (T) value, the PS increased the (T) value more than the CS. The (T) value was increased by a slight amount of cupric salt absorbed on the starch. In this case, the effect of kind of starch on the (T) value showed a similar tendency.