Oxidation Of Starch Research Articles

A Microbial Fuel Cell for Starch Oxidation

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Oxidation of fermented cassava starch using hydrogen peroxide

The effects of oxidation with hydrogen peroxide (H2O2) on the carbonyl and carboxyl content, pasting, expansion and textural properties of oven-dried fermented cassava starch were investigated. A 23 factorial design with three central points and six axial points was used to investigate the effect of H2O2 concentration, pH and temperature on the oxidation of fermented cassava starch; oven-dried and sun-dried fermented cassava starches were used as controls. The conditions of oxidation that presented the carbonyl and carboxyl contents of starch and specific volume and hardness of biscuits similar to the sun-dried fermented cassava starch were observed at the central point of the experimental design (1.5g/100g H2O2, pH 5.0 and 32.5°C). The sun-drying of the fermented cassava starch increased the carboxyl and carbonyl content, specific volume as well as decreased the biscuit hardness when compared to the oven-dried starch. The oxidation with H2O2 provides a fermented cassava starch with characteristics similar to the sun-dried fermented cassava starch and produces more homogeneous products.

Effect of deproteinization on degree of oxidation of ozonated starch

Effects of deproteinization on the degree of oxidation of ozonated starch (corn, sago, and tapioca) were investigated. Starch in dry powder form was exposed to ozone for 10 min at different ozone generation times (OGTs: 1, 3, 5, 10 min), and then native starches (NS) and deproteinized starches (DPS) were analyzed for protein content. Deproteinization caused a significant reduction in protein content for corn (∼21%) and sago (∼16%) starches relative to NS. Carbonyl and carboxyl contents increased significantly in all ozonated deproteinized starches (ODPS) with increasing OGT. Carbonyl and carboxyl contents of ODPS ranged from 0.03 to 0.13% and 0.14 to 0.28%, respectively. The carboxyl content for all ODPS was significantly higher than that of ozonated native starches (ONS). A Rapid Visco Analyser was used to analyze pasting properties of all starches. Deproteinization increased the pasting viscosities of corn and sago starches compared to their native forms. Generally, pasting viscosity of all ODPS decreased drastically as OGT increased. At the highest oxidation level (10 min OGT), all ODPS exhibited the lowest pasting viscosities compared to their ozonated native form, except for peak viscosity, breakdown viscosity, and setback viscosity for ozonated deproteinized corn starch. In conclusion, deproteinization as a pretreatment prior to starch ozonation successfully increased the degree of oxidation in the three types of starch studied. However, the extent of starch oxidation varied among the different starches, possibly due to differences in rates of degradation on amorphous and crystalline lamellae and in rates of oxidation of carbonyl and carboxyl groups.

Environmental friendly polysaccharide modification – microwave‐assisted oxidation of starch

AbstractA “green” method for oxidized starch preparation was presented. Hydrogen peroxide (H2O2) was used as the starch oxidant. Two main types of experiments were investigated: catalytic (by means of sodium tungstate – Na2WO4, the hydrogen peroxide activator) and non‐catalytic processes. The research covers low microwave level synthesis. Ninety and one hundred and ninety watts of microwave power were applied for the samples. All the microwave‐assisted reactions were compared to conventional ones carried out at 80 and 90°C, respectively. Reaction was monitored using manganometric determination of H2O2 consumption during the reaction progress. Obtained reaction products were tested by means of carbonyl and carboxyl group content. Additionally, molecular mass changes were investigated and a preliminary rheological study was done. The observed significant differences in the degree of oxidation (monitored by means of carboxyl and carbonyl group content) as well as the changes in molecular mass of polysaccharide comparing to those found at conventional conditions were showed and discussed.

Properties and sorption studies of polyethylene oxide–starch blended films

A series of polyethylene oxide (PEO) and starch blends were prepared by extrusion and their films prepared by compression molding. The mechanical, barrier, optical, thermal properties and surface morphology characteristics of PEO–starch blended films were studied. The tensile strength of the blended films decreased whereas the haze values increased with an enhanced starch concentration in PEO–starch blends. The inter-molecular interaction between PEO–starch blends were investigated with FTIR. The thermal properties were also analyzed by differential scanning calorimetric (DSC) and thermo-gravimetric analysis (TGA) techniques. Moisture-sorption characteristics of PEO–starch blended films were carried out at 27 °C for water activity (a w) ranged from 0.1 to 0.9. The sorption data at different a w were used to fit different sorption isotherm models as proposed in the literatures. The model constants were determined by linear fitting of the sorption equations. The high coefficient of determination R 2 (ranged from 0.7 to 1) confirms the applicability of the equations employed. The study on the application of such water activity data of PEO/starch blended films on different model equations will be helpful in prediction of durability and functional behavior of moisture sensitive biopolymeric films.

Batch and Semibatch Partial Oxidation of Starch by Hydrogen Peroxide in the Presence of an Iron Tetrasulfophthalocyanine Catalyst: The Effect of Ultrasound and the Catalyst Addition Policy

Oxidized starch is important for paper coating because of its good mechanical and sizing properties. Traditionally, starch oxidation is performed by different heavy metals as catalysts and chlorites or chlorines as oxidizing agents. In this study, an environmentally friendly method was developed, utilizing iron tetrasulfophthalocyanine as a catalyst only in small amounts and hydrogen peroxide as a clean oxidant. It has been previously shown that the method works well, but analysis of the kinetic data as well as catalyst deactivation was difficult because of the semibatch operation mode. In this study, hydrogen peroxide was employed in a batch mode, allowing more simple analysis methods for determining the degree of substitution, starch degradation, and hydrogen peroxide decomposition kinetics. Additionally, the effect of adding the catalyst continuously into the solution, as well as the influence of ultrasound treatment on starch prior to oxidation, was studied. The batch-mode results showed DSCOOH = 0.73 for 100 anhydroglucose units at 52 °C and pH 10, whereas adding the catalyst continuously increased DSCOOH to 1.62. An increased DSCOOH was obtained with the ultrasound-treated starch, which shows that ultrasound is a promising method for enhancing the reaction performance.

Development of a Starch Adhesive for Corrugated Board under Room Temperature

The use of starch as a renewable and biodegradable adhesive is becoming increasingly attractive because of the environmental concerns about the industrial wastes generated from petroleum products and the growing awareness of the potential deleterious consequences of greenhouse gas emissions from these activities. Starch adhesive is most extensively used in corrugated board industry because of the abundant supply, low cost, renewability, biodegradability, and ease of chemical modifications. Starch adhesive has great effect on the performance, production technology and manufacturing cost of the corrugated board. It is of great importance to develop starch adhesive with stable properties, high performance, good viscosity, fast curing speed to meet the market requirement. In this paper, oxidation of starch by sodium hypochlorite under aqueous alkaline conditions with the aid of the catalysis of nickel sulphate at room temperature was investigated. The effects of sodium hypochlorite loading and caustic soda dosage on the properties of the starch adhesive were examined. Optimization of starch oxidation is desirable to achieve the highest initial tack and bonding strength. The optimum synthesis condition was obtained. Under the optimum condition, Under the optimum condition, 98.7% of the initial tack and 11.4 N/25 mm of the bonding strength were obtained respectively.. The modified starch adhesive showed great potential for industrial application.

Molecular structure, rheological and thermal characteristics of ozone-oxidized starch

The effects of oxidation by ozone gas on the molecular structure, rheological and thermal properties of starch (corn, sago and tapioca) were investigated. Starch, in dry powder form, was exposed to ozone for 10min at different ozone generation times (OGTs). Average molecular weight decreased in oxidized corn and sago starches but increased in oxidized tapioca starch. All oxidized starches exhibited non-Newtonian shear-thinning behaviour. Starch viscosity decreased drastically with increasing OGT. Young’s modulus for all oxidized corn and sago starch gels stored for 1 and 7days at 4°C increased significantly compared to unmodified starch. No differences were noted in gelatinization temperatures and gelatinization enthalpies of all oxidized starches compared to unmodified starch. Retrogradation enthalpy increased markedly in corn starch after 1min OGT. These results show that the extent of starch oxidation varies among starches of different botanical origins under similar ozone treatment conditions.

Pasting, expansion and textural properties of fermented cassava starch oxidised with sodium hypochlorite

This study investigated the effects of oxidation with sodium hypochlorite on the content of carbonyl and carboxyl as well as pasting, expansion and textural properties of fermented cassava starch. A 23 factorial design with three central points and six axial points was used to investigate the effect of active chlorine concentration, pH and temperature during the oxidation of fermented cassava starch; oven-dried and sun-dried fermented cassava starches were used as controls. Sun-dried fermented cassava starch had a higher content of carboxyls and carbonyls, higher expansion and lower biscuit hardness compared to the oven-dried starch. Interestingly, the effect of oxidation was increased when the fermented cassava starch was oxidised with sodium hypochlorite. The highest values for the sum of carbonyl and carboxyl occurred at pH between neutral to alkaline, at high active chlorine concentrations and high temperatures. Oxidative treatment with sodium hypochlorite increases the expansion of starch and reduces biscuit hardness.

Low Catalyst Loadings for the Production of Carboxylic Acids from Polysaccharides and Hydrogen Peroxide

The oxidation of starch, xylans, potato flesh and wheat flour by H(2)O(2), in the presence of MSO(4) (M=Cu, Fe) as catalyst, led to depolymerization, and formation of solutions containing polyhydroxycarboxylic acids. Some of these oxidized compounds facilitate the process, leading to efficient transformations even with very low amounts of catalyst.

Polysaccharide Gels Based on Chitosan and Modified Starch: Structural Characterization and Linear Viscoelastic Behavior

We investigated the properties of polymeric systems formed by cross-linking chitosan with modified starch (oxidized maltodextrin). Such a macromolecular cross-linker proved to be efficient to react with chitosan with potentially minimal toxicity. The structural characterization of modified starch alone and of the two-polysaccharide reactive systems was performed using (1)H NMR and FTIR. The rheological behaviors of all systems, from solutions to gels, were also characterized. Depending on experimental parameters, such as chitosan concentration, cross-linking pH, degree of oxidation of starch, and molar ratio of reactive groups, different kinds of systems ranging from pure viscoelastic solutions to stiff hydrogels were formed. These versatile systems could be used in biomedical applications because of the good biocompatibility of their constituents.

Oxidation of cornstarch using oxygen as oxidant without catalyst

In the present work, oxygen was used as an environmentally friendly oxidant without catalyst, resulting in a waste free and simple method for starch oxidation. The oxidation was performed under the conditions of oxygen in sodium hydroxide at about 100 °C. It was found that the oxidation of the native cornstarch in this system depends upon the amount of sodium hydroxide, the temperature and the duration of the oxidation treatment. Twenty one gram NaOH, 100 °C and 3.0 h are the optimum conditions for getting the desirable water-soluble oxidized starch with carboxyl content of 3.6 g/100 g. The microstructure of oxidized cornstarch was characterized by scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR), Carbon-13 nuclear magnetic resonance spectroscopy ( 13C NMR) and chemical analysis methods. The results showed that the oxidation reaction introducing carboxyl and carbonyl groups took place at OH groups of C2, C3 and C6 in the glucose units and did not cause the breakage of C–O–C linkages.

Formic acid production from carbohydrates biomass by hydrothermal reaction

The formation of formic acid or formate salts by hydrothermal oxidation of model biomass materials (glucose, starch and cellulose) was investigated. All experiments were conducted in a batch reactor, made of SUS 316 tubing, providing an internal volume of 5.7 cm3. A 30 wt% hydrogen peroxide aqueous solution was used as an oxidant. The experiments were carried out with temperature of 250°C, reaction time varying from 0.5 min to 5 min, H2O2 supply of 240%, and alkaline concentration varying from 0 to 1.25 M. Similar to glucose, in the cases of the oxidation of hydrothermal starch and cellulose, the addition of alkaline can also improve the yield of formic acid. And the yield were glucose>starch> cellulose in cases of with or without of alkaline addition.

Photo-oxidation of rice starch. Part I: Using hydrogen peroxide

A process of oxidation of rice starch using UV irradiation and hydrogen peroxide (H 2O 2) as a photo-initiator was adopted. Factors affecting the photo-oxidation process were studied. The extent of oxidation was determined by determining the carboxyl content, the carbonyl content and the viscosity of the oxidized rice starch obtained. Study showed that optimum conditions for the oxidation system were: using 0.4% (based on weight of starch [ows]) of H 2O 2 and a material:liquor ratio ( M: L) of 1:6 at 60 °C for 4 h of UV irradiation. The produced oxidized rice starch was utilized as a sizing agent for cotton yarns. The sizing agent prepared (the oxidized rice starch) was evaluated by measuring the tensile strength (kg) and elongation at break (%) of the sized cotton yarns and determining of the percent of size removed from the sized cotton yarns by washing. Cotton yarns sized by oxidized starch used by Misr Company of Spining and Weaving in El-Mahalla El-Kubra was compared with the cotton yarns sized by our oxidized starch in terms of tensile strength, elongation at break and size removal (%). The results obtained were: 490 kg, 456 kg; 5.4%, 4.7%; and 86%, 55% for tensile strength, elongation at break and size removal (%) for cotton yarns sized by our oxidized starch and cotton yarns sized by oxidized starch used by the company, respectively. In other meaning our oxidized rice starch is competing with the oxidized starch used by the company.

High Carbonyl Content Oxidized Starch Prepared by Hydrogen Peroxide and Its Thermoplastic Application

AbstractHydrogen peroxide was used to oxidize gelatinized starch to oxidized starch (OS) with degree of oxidation (DO) ranging from 0.096 to 0.554 depending on the H2O2/starch molar ratios used. Then glycerol was added to OS to produce thermoplastic oxidized starches (TPOS). Titrimetric determination of carboxyl and carbonyl groups, FT‐IR, 1H‐NMR and 13C‐NMR confirmed that at H2O2/starch molar ratios < 0.7, oxidized starch contained much more aldehyde than carboxyl groups, while at molar ratios up to 2.0, peroxide oxidation produced mainly carboxyl groups. Scanning electron microscopy (SEM) revealed that the oxidized starch particles (at DO 0.385) obtained a porous structure. The effect of DO on the structure and properties of OS, as well as mechanical properties and moisture resistance of TPOS was studied, respectively. With an increase in DO, the crystallinity, intrinsic viscosity and thermal stability of OS decreased markedly, the ability of OS to take up water decreased at low DO and increased at higher DO. These observations show that hydrogen peroxide can be used to oxidize starch in a controlled way. TPOS with DO 0.385 showed the best mechanical properties, its tensile strength was 6.1 MPa after placing in 100% relative humidity for 15 days.

The physicochemical characteristics of oxidized polysaccharides

The paper presents the results obtained in studies of the physicochemical characteristics of modified polysaccharides prepared by the catalytic oxidation of starch with molecular oxygen in an alkaline medium. The amorphous-crystalline structure of starch was partially retained after oxidation. The differential scanning calorimetry data were used to determine the specific heat capacity of oxidized polysaccharides in the vitreous state over the temperature range 10–160°C and the enthalpy and temperature characteristics of fusion of amorphous-crystalline lamellae. The structural and thermodynamic parameters of crystallites (surface free energy, enthalpy, and entropy) were calculated. The segmental mobility of oxidized polysaccharide macromolecules and the transition from the vitreous to high-elasticity state were observed at Tg = 187.7°C, and the transition to the viscous-flow state, above 209°C. The pyrolysis of the polymer began after the unfreezing of its segmental mobility and was accompanied by the release of water and carbon dioxide and the formation of a large amount of coke foam.

Properties and structural characterization of oxidized starch/PVA/α‐zirconium phosphate composites

AbstractTwo series of composites, i.e., polyvinyl alcohol (PVA)/oxidized starch (OST)/exfoliated α‐zirconium phosphate (POST‐ZrPn) and PVA/starch (ST)/exfoliated α‐zirconium phosphate (PST‐ZrPn), were fabricated using a casting and solvent evaporation method. The composites were characterized by Fourier transform infrared spectroscopy (FT‐IR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (XRD), scanning electron microscopy (SEM), tensile testing, and moisture uptake. Compared with PST‐ZrPn, POST‐ZrPn films with the same component ratio showed higher tensile strength (σb), lower elongation at break (εb) and improved water resistance. Additionally, in the POST‐ZrPn series, σb and εb increased with an increase in α‐zirconium phosphate (α‐ZrP) loading; however, higher α‐ZrP loads resulted in the aggregation of α‐ZrP particles. Compared with POST‐ZrP0, the values for σb, εb, and water resistance of POST‐ZrP3, containing 1.5 wt % α‐ZrP, were increased by 128.8%, 51.4%, and 30.2%, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Influence of the oxidation and acetylation of banana starch on the mechanical and water barrier properties of modified starch and modified starch/chitosan blend films

AbstractBanana starch was oxidized at three different levels and afterwards acetylated. The double‐modified starch was used for film preparation with the addition of chitosan. The physical, mechanical, and barrier properties were tested. The oxidation level increased the moisture content of the film, but the acetylation and the addition of chitosan decreased this characteristic. The oxidation level increased the whiteness of the film, but the second modification (acetylation) and the addition of chitosan to the blend did not affect this parameter. The solubility increased with the temperature and the oxidation level but decreased with the storage time of the film. The oxidation increased and the acetylation reduced the solubility with respect to the native starch film. The dual modification produced a solubility value less than that of its oxidized counterpart, and the addition of chitosan produced the highest solubility value. The addition of chitosan increased the tensile strength of the film, and the effect was higher with the oxidation level and longest storage time. The addition of chitosan produced a higher elongation value than that of its double‐modified film, but at the longest storage time, this parameter decreased. The water vapor permeability increased with the oxidation level because of the hydrophilic character, but the acetylation reduced this parameter because the acetylation increased the hydrophobic character of the starch due to the ester group. Films prepared with the double‐modified banana starch and the addition of chitosan had some improved physical, mechanical, and barrier properties, and they may be used in specific applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The preparation and properties of dialdehyde starch and thermoplastic dialdehyde starch

Dialdehyde starch (DAS) is prepared by periodate oxidation of starch, and DAS with different aldehyde contents is plasticized by glycerol to obtain thermoplastic DAS (TPDAS). DAS is characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystalline starch is destroyed and oxidized to form amorphous DAS, while amorphous starch inside of starch granules is degraded. As a result, DAS containing 93.05% aldehyde content formes a ring shape. Compared to thermoplastic native starch, the re-crystallization of DAS can not take place in TPDAS during the storage period, because periodate oxidation has destroyed the crystallization of starch. With the increasing of aldehyde contents of DAS, the tensile strength and the resistance of both moisture absorption and water vapor permeability of TPDAS are improved. It is ascribed to the cross-linking of aldehyde groups in TPDAS.

Physicochemical and Functional Properties of Ozone-Oxidized Starch

The effects of oxidation by ozone gas on some physicochemical and functional properties of starch (corn, sago, and tapioca) were investigated. Starch in dry powder form was exposed to ozone for 10 min at different ozone generation times (OGTs). Carboxyl and carbonyl contents increased markedly in all starches with increasing OGTs. Oxidation significantly decreased the swelling power of oxidized sago and tapioca starches but increased that of oxidized corn starch. The solubility of tapioca starch decreased and sago starch increased after oxidation. However, there was an insignificant changed in the solubility of oxidized corn starch. Intrinsic viscosity [eta] of all oxidized starches decreased significantly, except for tapioca starch oxidized at 5 min OGT. Pasting properties of the oxidized starches followed different trends as OGTs increased. These results show that under similar conditions of ozone treatment, the extent of starch oxidation varies among different types of starch.