Starch In Presence Research Articles

Influence of disaccharide and monosaccharide on the rheological behavior of dry-heated alocasia starch under high pressure assisted treatment

High viscous products made with starch are of great scientific interest in the food, pharmaceutical, and cosmetic industries because they can be used to make creams and gels, as well as functional foods and nutritional products. But, obtaining a good quality highly viscous materials represent a technological challenge. In this present study, the effect of high-pressure treatment at 120 psi for different time interval on the mixture of dry-heated alocasia starch in presence of monosaccharide and disaccharide was studied. A flow measurement test on the samples revealed their shear-thinning behavior. With 15 min of high-pressure processing time, the dry-heated starch and saccharide mixtures displayed the highest viscosity. The dynamic viscoelasticity measurement showed that the storage and loss modulus was enhanced significantly after high-pressure treatment, and all pressure-treated samples showed a gel-like structure (G/>G//). In temperature sweep measurement, the rheological profile of storage modulus, loss modulus, and complex viscosity exhibited a two-stage pattern, i.e., first increased, then decreased, and their values were enhanced significantly after pressure treatment. The resultant highly viscous dry-heated starch and saccharide system have various functionalities in diverse food and pharmaceutical products.

Modification of corn starch by thermal-ultrasound treatment in presence of Arabic gum

This research extends the effects of a thermal-ultrasound treatment (at 25, 45, and 65 °C for 30 and 60 min) on the physicochemical, structural, and pasting properties of corn starch in presence of Arabic gum. Treated samples had lower leached amylose compared with corn starch, but it was non-significant (p < 0.05). In comparison to alone corn starch and a combination of Arabic gum, thermal-ultrasound treatment increased the swelling power and solubility of samples. Treatment significantly (p < 0.05) decreased the syneresis of treated starch gels, especially at a temperature of < 45 °C, but paste clarity was increased at the higher temperature (65 °C). The enthalpy of treated samples was in the range 15.20–16.37 J/g. Sonication at 65 °C for 60 min had the most destructive effect on corn starch granules, but at 30 min granules were swollen only. FT-IR spectra of samples confirmed the physical modification of thermal-ultrasound treatment. The relative crystallinity index of samples changed in the range 21.88–35.42% and decreased with rising time and temperature. Sonication at 45 °C for 30 and 60 min produced starch-gum mixtures with different pasting properties. Thermal-ultrasound treatment in presence of gum can be a viable technique to modify starches with different functionality.

A structural study of the self-association of different starches in presence of bacterial cellulose fibrils

A multi-analytical study was performed to analyse the effect of bacterial cellulose (BCF) on the self-association of starches with different amylose content (wheat, waxy-maize), assessing macrostructural properties (rheology, gel strength) and some nano and sub-nano level features (small and wide-angle X-ray scattering). Although pasting viscosities and G′ were significantly increased by BCF in both starches, cellulose did not seem to promote the self-association of amylose in short-range retrogradation. A less elastic structure was reflected by a 2–3-fold increase in loss factor (G″/G′) at the highest BCF concentration tested. This behavior agreed with the nano and sub-nano characterisation of the samples, which showed loss of starch lamellarity and incomplete full recovery of an ordered structure after storage at 4 °C for 24 h. The gel strength data could be explained by the contribution of BCF to the mechanical response of the sample. The information gained in this work is relevant for tuning the structure of tailored starch-cellulose composites.

Microwave assisted chemical modification of starch in presence or absence of amylase enzyme and its application in textile printing

The main aim of the current work is to investigate the influences of microwave irradiation (in absence of α-amylase enzyme) on the properties of different kinds of starches namely maize (MS), rice (RS), and wheat starch (WS). To achieve this goal. Starch was subjected to microwave irradiation in the absence of enzyme namely α-amylase under different conditions. The latter comprise is the starch concentration, time, and temperature of microwave irradiation. Furthermore, starch was subjected to microwave irradiation in the presence of enzyme under different conditions too. The latter comprises the concentration of enzyme and power level (watt) of microwave irradiation. The influence of these treatments on both the solubility as well as rheological properties of treated starches was thoroughly evaluated. Moreover, the visibility of using these treated starches as a thickening agent in burn-out printing style in printing paste was also investigated. The results of these investigations demonstrated that the optimum condition was found to be 10g starch (irrespective of the starch nature) in 100 ml water at pH 7 then added 0.2 ml of α-amylase enzyme. The mixture was cured at 55◦C for 3 minutes at 30 watts under microwave irradiation. Also, the obtained result showed that at a constant rate of shear the apparent viscosity increases by increasing the concentration of starch, temperature as well as time of treatment, irradiation of starches in presence of enzyme convert the rheological properties of starches from non-Newtonian thixotropic into non-Newtonian pseudoplastic. The prepared pastes were successfully used in printing wool/polyester (45/55) or wool/nylon (70/30). Where the loss in weight of the burn-out printed wool/polyester or wool/nylon is slightly higher on using modified starches compared with mypro gum. The color fastness of printed sample for rubbing, washing and perspiration was evaluated.

Synthesis of β-Cyclodextrin Immobilized Starch and Its Application for the Removal of Dyestuff from Waste-Water

A natural polymeric adsorbent, β-cyclodextrin immobilized starch (CS-βCD) was prepared by introducing host functional molecule β-cyclodextrin (β-CD) onto starch in presence of citric acid. The immobilization conditions were optimized to: m CA:m CS = 1:2, reaction time of 2 h and reaction temperature at 120 °C, by varying the input levels of the reactant, CS-βCD with a series of immobilization ratio (IR) and carboxyl content (CC) could be obtained. The FT-IR and 13C-NMR analysis indicated the β-CD molecules have been immobilized onto starch via the formation of ester linkages. The XRD and SEM analysis showed CS-βCD had more looser structure and more irregular surface compared with native starch. The GPC analysis showed CS-βCD had a reduced molecular weight but a more complicated molecular configuration. The adsorbing capacities of CS-βCD to three cationic dyes (methylene blue, methyl purple and basic fuchsin) were significantly improved compared with native starch, diatomite and zeolite. The adsorption behaviors of CS-βCD to the three dyes had high fitting degrees to both Langmuir and Freundlich models (R2 > 0.98). The decolourization ratio of CS-βCD to the mixed dyestuff waste-water had reached 88.75%, which was much higher than other absorbents. The results indicated the CS-βCD would become a high-efficiency dyestuff adsorbent, and would have a promising application in the industrial dyestuff waste-water treatment.

Synthesis, Bioactivities and In-silico Docking Studies of Azaleatin-A Quercetin Partial Methyl Ether: SAR Study

Background:During last two decades, good progress has been made for the flavonoids in metabolic and infectious diseases. However, expectations have not been fulfilled when these compounds were extended to the in vivo studies, particularly in humans. This could due to low bioavailability and less absorption of flavonoids in the biological systems. A recent study revealed that methylation of flavonoids can bring about dramatic changes in pharmacokinetic and biochemical properties. Often, the partially methylated flavonoids show better activities by improving their metabolic stability, membrane transport capacity, facilitating absorption and for oral bio-availability. Though, partial methyl ethers occupy a large chemical space, their biological properties has not been well established. Azaleatin (quercetin-5-O-methyl ether) is one of such group of naturally occurring molecules.Methods:In the present study, we have utilized methoxymethyl (MOM) protecting groups for the preparation of azaleatin. Synthesized compounds and their derivatives were subjected for &amp;amp;#945;-Amylase and DPPH activities. &amp;amp;#945;-Amylase activity can be measured in vitro by hydrolysis of starch in presence of &amp;amp;#945;-amylase enzyme. Antioxidant capacity was evaluated by measuring the scavenging activity of azaleatin and related compounds on the 2,2- diphenyl-l-1-picrylhydrazil (DPPH) radical. In order to identify the binding mode of the compound azaleatin, Auto Dock Tools (http://mgltools.scripps.edu) were used.Results:Quercetin, along with their derivatives, monomethyl ethers i.e. azaleatin, isorhamnetin, tamarixetin; dimethyl ether i.e. quercetin-3,7-dimethyl ether; quercetin-3,3&amp;amp;#039;,7-trimethyletherpachypodol; quercetin-3,3&amp;#039;,4&amp;#039;7-tetramethyl ether and quercetin pentamethyl ether were taken for &amp;amp;#945;- amylase inhibitory activity. The study showed that azaleatin was found to be comparable with the standard for the inhibition of &amp;amp;#945;-amylase amongst the tested compounds. Since, azaleatin is a best for the inhibition of &amp;amp;#945;-amylase, this compound was taken for the in-silico molecular modelling studies. Azaleatin, showed a good docking energy (-8.8 Kcalmol-1) with the &amp;amp;#945;-amylase receptor. Similarly, other closely related derivatives were studied for their antioxidant capacity. It was found that amongst the compound tested quercetin was found to be best (EC50 of 30&amp;amp;#181;g/mL) for their antioxidant capacity and second best compound was azaleatin; which showed EC50 of 36.1&amp;amp;#181;g/mL.Conclusion:An efficient synthesis of azaleatin, a lesser known flavone has been achieved from quercetin. Amongst the compounds tested, azaleatin was found to inhibit &amp;amp;#945;-amylase with the acceptable radical scavenging activity. Further, in-silico modelling studies indicated that azaleatin found to have very good affinity with the key residues i.e. Gln63, Asp197 and Arg195 of &amp;amp;#945;-amylase receptor. Since, azaleatin has other free hydroxyls in their template, it can be effectively utilized for the activity improvement through further structural modifications.

Physical properties of pregelatinized and granular cold water swelling maize starches in presence of acetic acid

Pregelatinized (PG) and granular cold water swelling (GCWS) starches are physically modified starches which are used to enhance viscosity at ambient temperature. The main aim of this research was to determine the physical changes of these starches in the presence of acetic acid (0, 500, 1000 and 10,000 mg/kg) as a common organic acid in foods. Native maize starch was converted to PG and GCWS starches using a twin drum drier and alcoholic-alkaline method, respectively. Scanning electron micrographs showed an increase in the size and central hole of the granules in GCWS starch and surface wrinkling of PG starch with increasing acid concentration. Water solubility increased, while water absorption, cold-water viscosity (as measured by a Rapid Visco Analyzer) and freeze–thaw stability of the samples reduced. A reduction in the paste viscosity, consistency, firmness and cohesiveness was observed as assessed using a Texture Analyser. Acetic acid increased the turbidity of GCWS starch but reduced the turbidity of PG starch pastes. The freeze–thaw stability of both samples reduced with addition of acetic acid, which was more pronounced after the first freeze–thaw cycle. These changes were enhanced with increasing acetic acid concentration. The changes caused by the acetic acid to the physical properties of PG starch were more obvious than those with GCWS starch.

Water and temperature contribution to the structuration of starch matrices in the presence of flavour

The effect of modulating the gelatinisation extent by hydration (50/50 and 80/20 water to starch ratio) and temperature (65 or 85°C) on various properties of wheat starch in presence of flavours has been studied. The hydrothermal treatments resulted in samples with different properties. The lowest residual flavour content was found in samples treated at the highest hydration and temperature (85°C) while the other treatment conditions led to samples with similar residual flavour content. Ethyl hexanoate significantly increased the characteristic pasting viscosities compared to starch±2-hexanone; suggesting a greater structuration with ethyl hexanoate. Heating starch in excess water caused amylopectin melting, but promoted an incomplete granular swelling as revealed by RVA. This study suggested that lowering the hydration upon treatment could limit both crystal melting (with a residual crystalline content up to 38% in the most extreme conditions) and granular swelling but increased granule organisation like following annealing.

Antimicrobial activity of silver/starch/polyacrylamide nanocomposite

A novel silver/starch/polyacrylamide nanocomposite hydrogel was prepared by grafting acrylamide onto starch in presence of silver nitrate by use of ammonium persulphate as an initiator and N,N-methylene-bisacrylamide as a crosslinking agent, then reducing the silver ions enclosed in the hydrogel structure to silver nanoparticles by treating the hydrogel with sodium hydroxide solution.All factors which affect the grafting/crosslinking reaction were optimized and the concentration of silver ion was changed from 0ppm to 50ppm. The produced nanocomposite hydrogel was characterized for its nanosilver content and the UV-spectra showed similar absorption spectra at wavelength 405nm for all AgNO3 concentrations but the plasmon showed increase in the intensity of the absorption peak as AgNO3 concentration incorporated to the hydrogel structure increases. The nanocomposite hydrogel was also characterized for its antimicrobial activity toward two types of bacteria and two types of fungi. The results showed that the hydrogel with 0ppm silver content has no antimicrobial activity, and that the antimicrobial activity expressed as inhibition zone increases as the silver content increases from 5ppm to 50ppm.

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.

Preparation of high‐substituted cationic starch in presence of organic bases

AbstractCross‐linked N‐(hydroxypropyl)–N,N,N–trimethylammonium starch chlorides (CQS) with preserved microgranules, degree of substitution (DS) from 0.18 to 1.05 are prepared by reaction of starch with glycidyltrimethylammonium chloride (GTAC) accelerated by benzyltrimethylammonium hydroxide (BTMAOH) or tertiary amines–triethylamine (TEA) and dimethylbenzylamine (DMBA). When BTMAOH instead of NaOH is used as a catalyst, the reaction of cross‐linked starch (CS) with GTAC proceeds slightly slower and with a lower efficiency (RE). DMBA unexpectedly showed similar catalyst efficiency as BTMAOH. It is suggested that the reason for such phenomena is the reaction of GTAC with tertiary amines and the formation of strong bases – quaternary ammonium hydroxides. They actually catalyse starch cationization. DMBA is more active in this reaction in comparison with TEA. It is shown that, due to a higher amount of quaternary ammonium hydroxides in the liquid phase of the reaction mixture, the yield of starch cationization decreases. Cationization in the presence of organic bases provides higher sorption capabilities to the modified polysaccharide.

Compatibilization of starch–zein melt processed blends by an ionic liquid used as plasticizer

An ionic liquid (1-butyl-3-methyl imidazolium chloride [BMIM]Cl) was used as a plasticizer in starch, zein and their blends; and compared to glycerol, a classical plasticizer of starch. Thermoplastic plasticized biopolymer materials were obtained by melt processing using a twin screw microcompounder. Such a device allows simulating a twin screw extrusion process on small batches of a few grams, and to evaluate the necessary specific mechanical energy input for native starch destructurization; and the final apparent melt viscosity. Both were shown to be significantly reduced for starch in presence of [BMIM]Cl (compared to glycerol), while zein processing behavior was less sensitive to the plasticizer used. This induces significant starch/zein viscosity ratio differences, which affect melt mixing of the starch zein blends. In starch rich blends, this results in smaller zein aggregates in the case of [BMIM]Cl.The characterization of the materials indicates that, compared to glycerol, the use of [BMIM]Cl leads to less hygroscopicity, a more efficient plasticization of both starch and zein phases and a compatibilization of starch/zein blends.

Compaction agglomeration of corn starch in presence of different binders

A model powder system comprising corn starch has been subjected to compaction agglomeration in presence of different binders like sugar (0–20%), pre-gelatinised starch (PGS) powder (0–20%) and vegetable oil (0–5%). The compacted masses are examined for density and different textural parameters (linear limit of deformation and modulus of deformability, and failure properties like failure stress/energy/strain) employing uniaxial compression. An increase in sugar and PGS markedly increases the failure stress, energy for failure and modulus of deformability while showing a reverse trend for oil added samples. The strain at failure increases with the addition of PGS and oil (6.9–14.5 and 6.9–24.4%, respectively) whereas marginal effect (6.9–8.1%) occurs with sugar. Compacted mass having 20% PGS behaves as the toughest sample. Cluster analysis among the textural parameters indicates a high similarity of 85% between failure stress and energy for failure. A mechanism of failure has been proposed for compacted mass during compression that has been supported by microstructures.

Prediction of the Glass Transition Temperature on Extruded Waxy Maize and Rice Starches in Presence of Glycerol

Polymer science approach has shown to be useful to understand the structural complexity of food systems. This work looks at the effect of glycerol (5%, 10%, and 20% (dry weight basis)) on the glass transition temperature (Tg) of a starchy matrix determined by DSC and its prediction using Ten-Brinke–Karasz equation. Waxy maize starch (WMS) and rice starch (RS) systems were prepared by thermomechanical extrusion. A decrease in Tg, from ∼170 to ∼25 °C, was detected for both starches (0% glycerol) when the moisture increased from 5% to 25% (wet weight basis (wb)). When glycerol was added, a further decrease in Tg was obtained. Tg was reduced from 120 to 60 °C and 45 °C for 10% and 20% glycerol, respectively, at a moisture content of 10% (wb). A direct comparison between starches with similar composition showed equal Tg (P > 0.05). The modeling for the control samples (0% glycerol) gave a ΔCp ∼ 0.4 Jg−1 K−1 for WMS and RS and ∼1.9 Jg−1 K−1 for water. These values can be explained by the well-known Tg dependence on degree of polymerization and molecular weight. When the glycerol concentration was increased, an increase was observed, ΔCp ∼ 0.6 Jg−1 K−1, for both starches and ∼2.8 Jg−1 K−1 for water. This behavior would indicate an overestimation in the plasticizing effect of glycerol due to the possible occurrence of polyol-rich fractions in the extruded samples.

Thermal Behavior of Selected Starches in Presence of Other Food Ingredients Studied by Differential Scanning Calorimetery (DSC)-Review.

This review article highlights the thermal behaviors of selected starches that were studied using differential scanning calorimetery (DSC) with data shown in various research publications. The starches of sago, potato, sweet potato, cassava, yam, and corn are included in this overview. Our examinations indicate that thermal properties are highly affected by the type of starch, its amylose/amylopectin content, and the presence of other food ingredients such as sugar, sodium chloride, water, milk, hydrocolloids, and meat. When the heating temperatures of the starches were increased, the DSC measurements also showed an increase in the temperatures of the gelatinization (onset [To ], peak [Tp ], and conclusion [Tc ]). This may be attributed to the differences in the degree of crystallinity of the starch, which provides structural stability and makes the granule more resistant to gelatinization.

Synthesis, Characterization and Saponification of Poly (AN)-Starch Composites and Properties of their Hydrogels

Hydrogels based on saponified products of poly (acrylonitrile, AN)-starch composites were prepared, characterized and their water abosrbency properties examined. The term composite refered to the resultant products of polymerizatin of AN with starch in presence of ceric ammonium nitrate (CAN) as initiator, that is the composite consists of poly(AN)-starch graft copolymer, homopoly(AN) , oxidized starch and unreacted starch. Thus AN monomer was polymerized with gelatinized starch using the ceric ion method. Gelatinization of starch prior to polymerization was affected by heating certain weight of starch in certain volume of distilled water at different temperrature (65, 75 and 85°C). Polymerization was carried out under a variety of coditions. Saponification of poly (AN)-starch composites was performed in sodium hydroxide to yield the hydrogels. The water absorbency properties of these hydrogels were found to rely on variables affecting the magnitudes of both polymerization and saponification. Among these variables mention was made of the starch/liquor ratio, cocentration of ceric ammonium nitrate (CAN), monomer/starch molar ratio, duration of grafting and gelatinization temperature as well as saponification time. Hydrogels display their maximum water absorbency when granular starch was firstly gelatinized at 85°C for 30 min and secondly subjected to polymerization with AN using AN/starch molar ratio of 4.8 and CAN concentration of 10 mmol/L liquor ratio of 12.5 and thirdly sample of the so obtained poly (AN)-starch composite was saponified in sodium hydroxide (0.7 N) at 95°C for 180 min. The saponified product was then precipitated in excess methanol, dried and finally converted into powder. The product (hydrogel) in the powder form exhibited maximum water absorbency of 920 g water per gram hydrogel and 38 mL synthetic urine per gram hydrogel.

Cationic starch: an effective flocculating agent

A series of cationic starches (Cat St) have been developed by incorporating a cationic moiety N-(3-Chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC) onto the backbone of starch in presence of NaOH. The cationic starches are characterized by elemental analysis, FTIR spectroscopy and intrinsic viscosity measurement. The flocculation characteristics of these starches have been evaluated in 0.25 wt% silica suspension by jar test. It has been found that among the four cationic starches, the one with longer CHPTAC chains shows the best performance. The flocculation characteristics of this starch are on silica suspensions compared with various commercially available flocculants.

Synthesis of Hydrophobic Starch Esters by Reaction of Starch with Various Carboxylic Acid Imidazolides

A novel efficient method of preparing hydrophobic starch esters with a DS = 1.55-2.0 using amylose enriched starch (amylomaize starch) or potato starch and a fatty acid imidazolide in DMSO as solvent is described. The fatty acid imidazolides can be easily prepared by conversion of the corresponding acyl chloride with imidazole in toluene according to a synthesis route developed by Staab et al. [1-4]. The by-product imidazole hydrochloride could be converted to imidazole by alkaline work up with Na 2 CO 3 . As compared with the direct esterification of starch in presence of a fatty acid chloride the presented synthesis method does not need toxic amines like pyridine as catalyst. Only a catalytic amount of a methanolic KOCH 3 solution is required. Furthermore no hydrolytic degradation of starch could be observed in contrast to the direct esterification reaction with a fatty acid chloride.

Modification of Carbohydrate Polymers via Grafting in Air. 1. Ceric-Induced Synthesis of Starch-g-Polyacrylonitrile in Presence and Absence of Oxygen

Monomer grafting, a unique technique for polysaccharide modification, is always performed under inert (e.g., N 2 ) atmosphere. This work is the first report related to evaluating the possibility and efficiency of the grafting of acrylonitrile (AN) onto starch in presence of oxygen. Thus, corn starch (in both granular and gelatinized states) as well as soluble starch were grafted by AN using a ceric-carbohydrate redox initiating system. Graft copolymerizations were performed under nitrogen, air, and oxygen atmospheres at similar conditions. Grafting occurrence was verified using chemical and spectral proofs. The polymerization mechanism and kinetics were investigated by recording the temperature variation of the exothermic reactions and by measuring grafting parameters. A paradoxical action of oxygen was observed. In spite of dictating a retardation period, molecular oxygen obviously favors efficient grafting of AN onto gelatinized starch. In case of soluble and granular starch, however, oxygen inhibits grafting under the same reaction conditions. Presence of DMF-insoluble fractions within the released polyacrylonitrile (PAN) side-chains, obtained from the starch-polyacrylonitrile (SPAN) products of reactions performed under O 2 and air, is attributed to some crosslinking reactions occurring during graft polymerization and/or acidic hydrolysis of the starch backbone of SPAN.

A novel chemical route for the preparation of nanosized oxides, phosphates, vanadates, molybdates and tungstates using polymer precursors

A variety of nanosized (particle diameter ranging between 10–90 nm) ceramic oxide powders have been prepared from a versatile, efficient and technically simple polymer matrix based precursor solution. The precursor solution constituted of the metal nitrates mixed with the polymer-PVA/PAA/carboxylated starch in presence of mono-/disaccharides or, poly hydroxy compound. Thermolysis/flame pyrolysis of the precursor mass at external temperatures of around 300–500°C resulted in the oxide phase.