Showing papers in "Starch-starke in 2006"
TL;DR: The physicochemical properties of the products were determined by means of Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction and Rapid Visco Analyser (RVA), and the results indicated that the suitable parameters for the preparation of OSA starch from early indica rice starch in aqueous slurry systems were as follows: concentration of starch slurry 35% (in proportion to water, w/w), reaction period 4 h, pH of reaction system 8.5, reaction temperature 35°C,
Abstract: Octenyl succinic anhydride (OSA) modified early indica rice starch was prepared in aqueous slurry systems and the major factors affecting the esterification were investigated systematically. The physicochemical properties of the products were determined by means of Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction and Rapid Visco Analyser (RVA). The results indicated that the suitable parameters for the preparation of OSA starch from early indica rice starch in aqueous slurry systems were as follows: concentration of starch slurry 35% (in proportion to water, w/w), reaction period 4 h, pH of reaction system 8.5, reaction temperature 35°C, amount of OSA 3% (in proportion to starch, w/w). The degree of substitution (DS) was 0 018 and the reaction efficiency (RE) was 78%. FT-IR spectroscopy showed characteristic absorption of the ester carbonyl groups in the OSA starch at 1724 cm -1 . SEM and X-ray diffraction revealed that OSA groups acted by first attacking the surface and some pores formed, but OSA modification caused no change in the crystalline pattern of rice starch up to DS 0.046. RVA results indicated that the starch derivatives gelatinized at shorter time to achieve higher viscosities with increased OSA modification.
227 citations
TL;DR: In this article, a cross-linked cassava starch was crosslinked with epichlorohydrin (EPI) at 45°C for 2h in three different media which include water, water in the presence of a phase transfer catalyst (PTC) and N,N-dimethylformamide (DMF).
Abstract: Cassava starch was cross-linked with epichlorohydrin (EPI) at 45°C for 2 h in three different media which include water, water in the presence of a phase transfer catalyst (PTC) and N,N-dimethylformamide (DMF). The products were characterized by determining their physicochemical, thermal and retrogradation properties. In aqueous medium, the use of a PTC, tetrabutylammonium bromide (TBAB) produced derivatives with higher degree of cross-linking than those prepared without the use of the catalyst. The degree of cross-linking was found to be higher using the same concentration of EPI when the reaction was carried out in DMF. At low levels of cross-linking, the peak viscosity of the cross-linked starches increased in comparison to that of the native starch. With increasing degree of cross-linking, the peak viscosity showed a significant reduction. The swelling volume, solubility and light transmittance of the starch pastes were lower for the modified starches. The cross-linked starches showed slightly reduced values for the gelatinization temperatures, Tonset, Tpeak and Tend. The enthalpy of gelatinization of the modified starches increased with increase in the degree of cross-linking. The modified starches exhibited higher water-binding capacities (WBC) than the native starch; but with increase in the degree of cross-linking, there was a gradual decrease in WBC. The in vitro alpha amylase digestibility of the modified starches decreased gradually with increase in the level of cross-linking.
164 citations
TL;DR: The wide range of physicochemical properties among non-waxy rice lines allows breeders to obtain breeding lines with desirable grain quality and food processors to select unique rice materials for specialty food processing, in addition to the applications in other processing industries.
Abstract: A total of 499 non-waxy rice lines including 172 landraces (the landrace set) and 327 cultivars and breeding lines (the breeding line set) were used to study the genetic diversity of starch physicochemical properties, and the differences between the landrace set and the breeding line set were compared. All the rice lines were planted in the same season and at the same location in Hainan province. Wide diversities of starch physicochemical properties were found, e.g. apparent amylose content ranged from 7.9% to 33% in normal rice and up to 39.8% in an amylose extender mutant; peak viscosity ranged from 90.1 to 305.4 RVU, hot paste viscosity from 77.5 to 248.1 RVU, and cold paste viscosity from 111.4 to 412.6 RVU; gel hardness ranged from 9.4 to 61.1 g. The breeding line set had a wider range of physicochemical properties than the landrace set with a rare exception in gel hardness. The mean values of nearly all the parameters showed significant differences between the two sets of rice except for the setback ratio. The adhesiveness and cohesiveness of landrace starches were significantly lower than those of the breeding lines whereas the other parameters of the landrace set were higher than those of the breeding line set. Analysis of correlation among these parameters indicated that most of the traits were significantly correlated. The wide range of physicochemical properties among non-waxy rice lines allows breeders to obtain breeding lines with desirable grain quality and food processors to select unique rice materials for specialty food processing, in addition to the applications in other processing industries.
144 citations
TL;DR: In this article, composites of corn starch (CS) and chitosan (CH) were developed from microstructure studies using scanning electron microscopy (SEM), and the addition of glycerol reduced film opacity and increased film solubility.
Abstract: Biodegradable flexible films were developed from corn starch (CS) and chitosan (CH); their microstructure, mechanical and barrier properties were evaluated. Chitosan and starch blend filmogenic suspensions showed a pseudoplastic behavior, similar to that of chitosan solutions. Smooth surfaces, homogeneous and compact film structures were observed from microstructure studies using scanning electron microscopy (SEM). The addition of glycerol reduced film opacity and increased film solubility of both CS and composite CS-CH films. Water vapor permeability values of composite CS-CH films plasticized with glycerol ranged between 3.76 and 4.54 × 10 -11 g s -1 m -1 Pa -1 , lower than those of the single component films. CS-CH films were resistant and their flexibility increased with glycerol addition. Tensile strength values of CS-CH films were comparable to those of low-density and high-density polyethylenes but lower than that obtained for cellophane, however, composite biodegradable films showed lower elongation at break values than the synthetic commercial ones. In conclusion, CS-CH films can be described as biofilms with a homogeneous matrix, stable structure and interesting water barrier and mechanical properties, with great possibilities of utilization, and with the advantage of biodegradability.
136 citations
TL;DR: A review of the principle and technologies in reactive extrusion and their application in starch modification and preparation of starch derivatives, such as starch graft copolymers, glycosides, cationic starch, or oxidized starch is presented in this article.
Abstract: This paper presents a review of the principle and technologies in reactive extrusion and their application in starch modification and preparation of starch derivatives, such as starch graft copolymers, glycosides, cationic starch, or oxidized starch. The applications of reactive extrusion in producing other biopolymers are also touched. Flexibility and efficiency of reactive extruders as reactors for biopolymers are particularly noteworthy.
122 citations
TL;DR: In this paper, normal maize, waxy maize and amylomaize V starches were treated at a moisture content of 30% by microwave radiation and the results showed that the surface was porous and a cavity could be clearly observed at the center of the three starches.
Abstract: Normal maize, waxy maize and amylomaize V starches were treated at a moisture content of 30% by microwave radiation. The results showed that the surface was porous and a cavity could be clearly observed at the center of the three starches. Microwave treatment increased the X-ray intensities of the major d-spacings of all starches and changed the X-ray pattern of amylomaize V from B to A+B. The swelling power (amylomaize V normal maize > amylomaize V) and the enthalpy of gelatinization (amylomaize V (B-type)> normal maize waxy maize (A-type)) decreased on this treatment. Microwave treatment increased the gelatinization transition temperatures (amylomaize V > waxy maize > normal maize) and the gelatinization temperature range (amylomaize V > normal maize iO waxy maize) of all starches. A rise in pasting temperature and a drop in viscosity of the three starches were observed after microwave irradiation. The viscosity patterns of waxy and normal starches remained unchanged, while that of amylomaize V starches changed from C to D on microwave treatment. The data showed that rearrangements restricted to sections of the starch molecules resulted in the formation of new crystallites of different stabilities and led to a more ordered crystalline array.
109 citations
TL;DR: In this article, the influence of various factors, including starch granule channels, have been suggested to contribute to the control of sorghum starch digestibility for animal feed, and the results showed that the channels in starch granules are the main route of enzyme penetration and the central cavity area is the starting point of enzyme digestion.
Abstract: Various factors, including starch granule channels, have been suggested to contribute to the control of sorghum starch digestibility for animal feed. Isolated starch from two normal sorghum lines (P721N, IS6986) and one high protein digestibility (HPD) mutant line (111) that differed in starch granule morphology were selected to study the influence of these factors on starch digestibility. Scanning electron micrographs were taken of raw and digested starches. Microscopy results confirmed that in all three sorghum lines channels in starch granules are the main route of enzyme penetration and the central cavity area is the starting point of enzyme digestion. Channel density was more pronounced in the HPD sorghum mutant line than in normal lines, which may have been responsible for its relatively high digestibility. Micrographs of IS6986 showed unique starch granule morphology with a collapsed ”doughnut-shaped” structure in a portion of the granules. These unusual granules were rapidly digested and, unlike normal spherical granules, totally disappeared after 30 min of digestion. Amylases appeared to have fast access to the collapsed-appearing starch granules. Digestion profiles, following incubation with pepsin and α-amylase, showed that IS6986 and the HPD mutant (111) had the highest initial rate of starch digestion, followed by P721N. These findings provide insight as to how new sorghum cultivars might be developed with high starch digestibility for animal feed use.
105 citations
TL;DR: Using a very low concentration of potassium persulfate as initiator, acrylamide could be efficiently grafted onto potato starch under microwave irradiation and for the grafting O 2 removal from the reaction vessel was not required.
Abstract: Using a very low concentration of potassium persulfate as initiator, acrylamide could be efficiently grafted onto potato starch under microwave irradiation and for the grafting O 2 removal from the reaction vessel was not required. Under optimal conditions, grafting and efficiency observed were 160% and 89%, respectively. Grafted starch was characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It was observed that the microwave irradiation could significantly accelerate the synthesis of starch-graft-poly(acrylamide), because under identical conditions no grafting was observed in a conventional procedure. Viscosity, shear stability and water/saline solution retention of the microwave-synthesized grafted starch were studied and compared with that of the parent starch.
105 citations
TL;DR: Araucaria angustifolia seeds are composed of 34% of starch and very low fractions of protein, lipids and phenolic compounds, which is favorable to obtain a stable, white in color and odorless starch, useful in the food industry as mentioned in this paper.
Abstract: The pinhao seeds (Araucaria angustifolia), are composed of 34% of starch and very low fractions of protein, lipids and phenolic compounds. This composition is favorable to obtain a stable, white in color and odorless starch, useful in the food industry. The isolated starch is constituted predominantly of small-sized round granules (10–25 μm), rather than oval ones. Compared to corn starch, pinhao starch has a lower temperature and enthalpy of gelatinization. Retrogradation occurs to a lower extent in pinhao starch, due to its lower amylose content (∼25%). The pasting profile of pinhao starch showed a higher consistency than that of corn starch, with lower temperature in the peak of maximum viscosity. The higher swelling and solubility values of pinhao starch, in conjunction with the higher storage modulus (G') suggest new different applications of this novel starch. The low protein content of the starch granule favors applications like production of glucose and fructose syrups. The simple method of extraction and the high yield of starch from pinhao seed might be attractive not only for pilot-plant but also for commercial-scale production.
96 citations
TL;DR: In this article, the flocculation efficiency of cationic starch derivatives of varying degrees of substitution (DS) and different amylose/amylopectin ratios was investigated and compared to structural properties.
Abstract: In this study the flocculation efficiency of cationic starch derivatives of varying degrees of substitution (DS) and different amylose/amylopectin ratios was investigated and compared to structural properties. The molar masses, Mw, radii of gyration, RG, and the molar mass distributions of the starch samples were determined by applying the method of flow field-flow-fractionation combined with multi-angle light scattering and interferometric refractometry. In dewatering experiments potato starch derivatives of differing DS have optimum dosages that correspond to their cationicity. The lowest flocculant dosage yielding maximum dewatering results was determined for the most strongly substituted sample (DS = 1.48), while the least substituted starch derivative (DS = 0.28) showed the highest flocculant demand. Furthermore, the molar mass distribution and coil dimensions of derivatives seem to have a great influence on flocculation efficiency, because a 1.5-fold increase in molar mass can compensate a 1.5-fold decrease in DS. Toxicological investigations on synthetic and natural flocculants employing hens fertile egg screening test (HEST) led to the conclusion that cationic starches of DS < 0.95 are less toxic than commercial synthetic flocculants. When the results of flocculation experiments and toxicological data were taken into account, a moderate DS of 0.6 was deemed to give the best compromise between dewatering efficiency, cost-effectiveness and ecological safety.
91 citations
TL;DR: In this article, a B-type X-ray diffraction pattern and water vapor permeability were used to test the tensile strength, elongation, and X ray diffraction patterns.
Abstract: Films were prepared using oxidized banana starch and glycerol. Oxidized banana starch was synthesized at three oxidation levels (0.5, 1.0 and 1.5% of active chlorine). Thermal gelatinization and casting were used for film preparation. Tensile strength, elongation, X-ray diffraction pattern and water vapor permeability were tested. The tensile strength of the films was higher when the oxidation level of the banana starch was higher. When films were stored for 30 and 60 days, there were no statistical differences in tensile strength. However, differences occurred when those films were compared with the films stored for 90 days. The film with added sunflower oil presented the lowest value of elongation at 30 and 60 days of storage. When elongation values were assessed at 90 days of storage no statistical differences (α=0.05) were found among the films prepared from native starch with added sunflower oil, oxidized banana starch with 1.0% and oxidized banana starch with 1.5% oxidation level. All films had a B-type X-ray pattern. When the oxidation level in the starch increased, the peaks of crystallinity of the films increased as well. An additive effect was shown due to the higher interactions among polymer chains and among polymer and glycerol molecules as determined by the mechanical properties of the films analyzed. The corrected water vapor permeability (WVPc) of the films stored for 30 and 60 days did not show statistical differences (α=0.05). The films prepared with oxidized banana starch had the highest WVPc and those values increased when the oxidation level in the starch was higher. Oxidized banana starch can be used for preparation of films with adequate physicochemical characteristics.
TL;DR: In this article, the swelling and pasting properties of nonwaxy rice starch-hydrocolloid mixtures were investigated using commercial and laboratory-generated hydrocolloids.
Abstract: The swelling and pasting properties of non-waxy rice starch-hydrocolloid mixtures were investigated using commercial and laboratory-generated hydrocolloids. The swelling power of the rice starch-hydrocolloid mixtures was generally depressed at low concentration of hydrocolloids (0–0.05%), but increased directly with increasing hydrocolloid concentrations (0.05–0.1%). In gellan gum dispersion, the swelling power at 100°C was higher than that of control. The rice starch-hydrocolloids mixtures showed shear-thinning flow behavior (n = 0.26–0.49). Hydrocolloids except the exopolysaccharide from S. chungbukensis (EPS-CB) increased apparent viscosity and consistency index (K) of rice starch dispersions, but decreased the n value. Hydrocolloids enhanced the trough and final viscosity of rice starch dispersions but EPS-CB reduced the viscosity of rice starch pastes. Hydrocolloids lowered peak viscosity but addition of guar gum resulted in high peak viscosity, apparent viscosity, and consistency index of rice starch dispersions. Total setback viscosity appeared to be not affected by hydrocolloids at low concentration (0.05%). The hot and cold paste of the starch-gellan gum mixture exhibited the highest viscosity values in the Brookfield viscometer.
TL;DR: In this paper, a starch maleate was prepared by microwave-assisted reactions in a dry medium for 5 min, achieving a reaction efficiency of 98% and an energy saving with high reaction efficiency.
Abstract: Starch maleate was prepared by microwave-assisted reactions. Microwave-assisted esterification in a dry medium for 5 min gives a reaction efficiency of 98%. Influences of reaction time, reagent molar ratio and water content of starch on the degree of substitution (DS) of the product and reaction efficiency were investigated. The structure of starch maleate was characterized by FTIR and NMR spectroscopy. Changes in the starch granules before and after modification were studied by scanning electron microscopy (SEM). Compared with the conventional heating synthesis method, microwave-assisted synthesis in a dry medium is rapid and energy saving with high reaction efficiency.
TL;DR: The morphology and microstructure of maize starches with different amylose/amylopectin ratios were studied by microscopy with ordinary and polarized light, scanning electron microscopy (SEM) and X-ray diffraction (XRD) as mentioned in this paper.
Abstract: The morphology and microstructure of maize starches with different amylose/amylopectin ratios (waxy: 0/100; normal maize: 23/77; Gelose 50: 50/50; Gelose 80: 80/20) were studied by microscopy with ordinary and polarized light, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Generally, the granules of the amylopectin-rich starches were more regular in shape than those of the amylose-rich starches, but the surfaces of the amylose-rich starches were smoother than those of the amylopectin-rich starches. The birefringence and particle size of the granules were waxy > normal maize > G50 > G80, which also corresponds with the trend of molecular weight. Waxy and normal maize starches showed typical A-type patterns, while G50 and G80 show B-type patterns. Crystallinity increases with increasing the amylopectin content.
TL;DR: The effect of galactomananns (guar gum and locust bean gum) at different concentrations on the dynamic rheological properties of aqueous rice starch dispersions was investigated by small-deformation oscillatory measurements during aging as discussed by the authors.
Abstract: The effect of galactomananns (guar gum and locust bean gum) at different concentrations (0, 0.2, 0.4, 0.6 and 0.8%, w/w) on the dynamic rheological properties of aqueous rice starch dispersions (5%, w/w) was investigated by small-deformation oscillatory measurements during aging. Magnitudes of storage (G′) and loss (G′′) moduli measured at 4°C before aging increased with the increase in gum concentration in the range of 0.2–0.8%. G′ and G′′ values of rice starch-locust bean gum (LBG) mixtures, in general, were higher than those of rice starch-guar gum mixtures. G′ values of rice starch-guar gum mixtures as a function of aging time (10 h) at 4°C increased rapidly at initial stage and then reached a plateau region at long aging times. However, G′ values of rice starch-LBG mixtures increased steadily without showing a plateau region. Increasing the guar gum concentration resulted in an increase in plateau values. The rate constant (K) for structure development during aging was described by first-order kinetics. K values in rice starch-guar gum mixtures increased with the increase in guar gum concentration. G′ values of rice starch-galactomannan mixtures after aging were greater than those before aging.
TL;DR: In this article, a Rheoner instrument was used to evaluate three textural parameters, namely, the breaking force (BF), breaking energy (BE), and ratio of the breaking forces to the breaking deformation (BF/BD), of instant noodles cooked by immersing into boiling water for 3 and 7 min.
Abstract: The properties of potato starch and their effect on the quality of Chinese-style alkaline instant noodles made from wheat flour and potato starch blends were investigated. Starches were extracted from nine potato cultivars, and the phosphorus content of these starches was analyzed together with the median granule size and pasting and gelatinization properties. Instant noodles were manufactured using mixtures of wheat flour and these potato starches. A Rheoner instrument was used to evaluate three textural parameters, namely, the breaking force (BF), breaking energy (BE), and ratio of the breaking force to the breaking deformation (BF/BD), of instant noodles cooked by immersing into boiling water for 3 and 7 min. The phosphorus content, peak viscosity, and breakdown were significantly and positively correlated with the BF of the noodles cooked for 3 min and did not significantly correlate with that of those cooked for 7 min. Other quality parameters of potato starch did not affect the BF significantly. Other textural parameters of instant noodle quality, such as the BE and BF/BD, did not significantly correlate with any of the quality parameters of potato starch. The findings obtained with the use of wheat flour and potato starch blends suggest that phosphate, which is thought to enhance starch viscosity of potato starch, is important for making instant noodles with favorable texture in hardness.
TL;DR: In this article, structural and functional properties of starch from high-protein, lipoxygenase-free and low-linolenic acid soybean variety seeds collected 20 d prior to harvest were investigated.
Abstract: Structures and functional properties of starch from high-protein, lipoxygenase-free and low-linolenic acid soybean variety seeds collected 20 d prior to harvest were investigated. Soybean starches exhibit CB-type X-ray diffraction patterns, and granule diameters were very small (0.7 to 4 micrometer). Soybeans, 20 d prior to harvest contained 10.9-11.7% starch (dry basis). Apparent amylose content was 19-22% and absolute amylose content was 11.8-16.2%. Amylopectin weight-average molar mass ranged from 5.1 to 11.3x108 g/mol. Amylopectin average branch chain-length, determined by anion-exchange chromatography with an amyloglucosidase post-column and pulsed amperometric detector, was very short relative to other starches (20.4-20.9). Onset gelatinization temperature ranged from 52-54°C, and H was 12-13 J/g. Paste viscosity was low relative to other starches, especially peak (81-93 RVU) and final (93-106 RVU) viscosity. The apparent amylose content of the low-linolenic acid soybean starch was significantly higher than that of high-protein soybean starch, and absolute amylose content of low-linolenic acid soybean starch was significantly higher than that of lipoxygenase-free soybean starch. Based on our results, investigations on whether soybeans with different fatty acid oil composition have different starch structures would be worthwhile. Field replicates for each soybean variety exhibited high variation in starch characteristics, with further differences in starch structures and functional properties likely to be determined once variation is minimized.
TL;DR: In this article, the authors evaluated the performance of rice starch pastes at 25°C and found that the activation energy (Eg) values of the pastes were in the range of 9.46-11.4 kJ/mol.
Abstract: Rheological properties of acetylated rice starch pastes (5%, w/w) as a function of acetyl degree of substitution (0.025-0.104) were evaluated in steady and dynamic shear. The acetylated rice starch pastes at 25°C had high shear-thinning behavior (n = 0.17-0.20) with high Casson yield stress (σ OC = 47.4-84.1 Pa). Magnitudes of consistency index (K) and yield stress (σ OC ) increased with increase in acetyl substitution degree. Apparent viscosity (η a,100 ) obeyed the Arrhenius temperature relationship over the temperature range of 10-55°C; the activation energy (Eg) values of acetylated starch pastes were in the range of 9.46-11.4 kJ/mol. Magnitudes of storage modulus (G'), loss modulus (G") and complex viscosity (η*) of acetylated starch pastes increased with increase in degree of acetyl substitution, and the magnitudes of G' were also much greater than those of G" and η* at all values of frequencies (ω). The Cox-Merz superposition rule did not describe the relationship between dynamic (η*) and apparent viscosity (η a ) for all samples.
TL;DR: In this paper, an autocatalytic reaction of GTAC with starch proceeds more rapidly at higher temperatures but with lower reaction efficiency, both in the absence of the external catalyst and in the case when sodium alkali is used as a catalyst.
Abstract: Cationic starch derivatives containing quaternary ammonium groups with high degree of substitution are prepared by reaction of starch with glycidyltrimethylammonium chloride (GTAC) in different reaction media. In aqueous solutions of GTAC along with conventional hydrolysis of epoxy groups, their interaction with chloride ions also takes place. This resulted in formation of hydroxyl ions which accelerate both the hydrolysis of GTAC epoxy groups and can act as the internal catalyst in the reaction of GTAC with starch. Therefore, even in the absence of the external catalyst, cationic starch with a high degree of substitution can be obtained. The autocatalytic reaction of GTAC with starch proceeds more rapidly at higher temperatures but with lower reaction efficiency. Both in the absence of the external catalyst and in the case when sodium alkali is used as a catalyst the reaction of starch with GTAC proceeds only when a particular quantity of “free” water is present in the system. When the NaOH as catalyst is used the reaction efficiency is about 90%. The yield of starch cationization reaction decreases when the quantity of “free” water is twice or thrice higher than required for starch modification to begin.
TL;DR: In this paper, the authors used near-infrared (NIR) spectroscopy measurements of potato mash to estimate the starch and protein parameters of potato tubers and validated the results with an independent data set.
Abstract: Starch and protein parameters of potato tubers were estimated by near-infrared (NIR) spectroscopy measurements of the crude potato mash. Calibration was carried out with a condensed data set of original 1481 individual samples from a varying number of varieties and breeding lines, grown at eight locations over a three-years period. Validation of the models was performed with an independent data set (n = 133). Starch content of potato tubers was determined with the official under-water weighting procedure of the EU, and could be predicted with 90% confidence. The NIR model of phosphorus content of starch had a prediction confidence of 53%. Total protein content could be predicted, too (62% confidence), whereas the amount of coagulable protein was not predictable (R2 = 0.25). Despite the different qualification levels of the models, guiding to concrete prediction tools or to a very rough estimation graduating from “low” to “high”, the NIR technique enables potato starch processing plants to optimise both potato starch quality and processing efficiency.
TL;DR: In this paper, the protein detection of Brazilian rice starch granules was performed using UV/Vis and fluorescence spectroscopy. And the results were compared to the traditional biuret colorimetric test.
Abstract: Alkaline extraction of Brazilian rice starch was studied. UV/Vis and fluorescence spectroscopy were employed as an innovative way for protein detection during the extraction. Moreover, the results were compared to the traditional biuret colorimetric test. In parallel, the ultrastructure of starch was monitored by small angle X-ray scattering (SAXS) during every extraction step. A progressive reduction of the granules organization was observed, which was also detected by the loss of birefringence under polarized light. The external integrity of starch granules after complete removal of proteins was maintained, as verified by scanning electron microscopy (SEM). The size of the granules, determined by the Mie scattering method varied between 3 and 8 µm.
TL;DR: In this article, an ethylenebisformamide was synthesized and used as a novel plasticizer for corn starch to prepare thermoplastic starch (EPTPS) FT-IR spectra showed that the absorption bands of the C-O groups of the starch molecules were shifted to lower wavenumbers, which indicated that a strong and stable hydrogen bond had been formed between ethylene bisformamide and starch.
Abstract: In this paper, ethylenebisformamide was synthesized and used as a novel plasticizer for corn starch to prepare thermoplastic starch (EPTPS) FT-IR spectra showed that the absorption bands of the C-O groups of the starch molecules were shifted to lower wavenumbers, which indicated that a strong and stable hydrogen bond had been formed between ethylenebisformamide and starch By scanning electron microscope (SEM) native individual corn starch granules were proved to transfer to a continuous phase The crystallinity of native corn starch, GPTPS (glycerol plasticized corn starch) and EPTPS was characterized by X-ray diffraction (XRD) Water resistance of EPTPS was better than that of GPTPS It decreased from 502% for GPTPS to 378% for EPTPS The mechanical analysis showed that elongation at break increased markedly, being 260% for the EPTPS containing 35% (w/w) ethylenebisformamide Thermal stability of GPTPSs and EPTPSs was also determined by thermogravimetric analysis (TGA) The glass transition temperature T g , as measured by dynamic mechanical thermal analysis (DMTA), of EPTPS was higher than that of GPTPS
TL;DR: In this article, the physical properties of acorn (Quercus palustris) starch were studied and an A-type X-ray diffraction pattern, an apparent amylose content of 43.4% and absolute amyloses content of 31.4%.
Abstract: Physicochemical properties of acorn (Quercus palustris) starch were studied. Acorn starch granules were spherical or ovoid, with diameters ranging from 3-17 pm. Acorn starch exhibited A-type X-ray diffraction pattern, an apparent amylose content of 43.4% and absolute amylose content of 31.4%. Relative to other A-type starches, acorn amylopectin had a comparable weight-average molar mass (3.9×10 8 g/mol), gyration radius (288 nm) and density (16.3 g mol -1 nm -3 ). Average amylopectin branch chain-length corresponded to DP 25.5. Onset gelatinization temperature was 65.0°C and peak gelatinization temperature was considerably higher (73.7°C). The enthalpy change of gelatinization was very high compared to non-mutant starches (20.8 J/g). An amylose-lipid thermal transition was not observed. Starch retrograded for 7 d at 4°C had very high peak melting temperature (54.2°C) relative to other A-type starches. Final (260 RVU) and setback (138 RVU) viscosity of an 8% acorn starch paste was high relative to other starches and pasting temperature was 71.5°C.
TL;DR: In this article, a simple calorimetric method for determination of amylose content in starch is reported, where starches were heated in the presence of two common surfactants, viz., sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB), and the enthalpies of melting of the amyloses-surfactant complexes were determined using Modulated Differential Scanning Calorimetry (MDSC).
Abstract: A simple calorimetric method for determination of amylose content in starch is reported. Starches were heated in the presence of two common surfactants, viz., sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB), and the enthalpies of melting of the amylose-surfactant complexes were determined using Modulated Differential Scanning Calorimetry (MDSC). A large number of native starches including cereal, root and pea starches were examined. The results were compared with those obtained by iodimetry and gel permeation chromatography (GPC) for all the starches. There was a good correlation between the values from iodimetry and GPC with those obtained using the surfactants. Both surfactants seemed to work equally well, even for those starches with about 40% amylose content. However, in case of SDS higher standard deviations were usually obtained than for CTAB in the determination of transition enthalpies.
TL;DR: The structural elements of amylopectin were essentially constant in terms of unit chain distributions and chain lengths, and the average chain length was 17-20 as mentioned in this paper, and a fraction of extra-long chains in the range of 0.24-1.78% was found.
Abstract: Starches from 12 cassava varieties with different cooked root texture; i.e. mealy, firm and mealy and firm, were investigated with a particular focus on aspects of molecular structures of amylose and amylopectin. Structural elements of amylopectin were essentially constant in terms of unit chain distributions and chain lengths. All cassava amylopectins displayed two distinct chain length peaks, at DP 40-46 and at DP 11-13, with a shoulder at DP 17-19, and average chain length (CL) of amylopectins was 17-20. A fraction of extra-long chains in the range of 0.24-1.78% was found. Amylose and amylopectin from four varieties with different textures of cooked root were isolated. Data from C-chain distributions indicated that the molecular size of amylopectin from M-hanatee (Hanatee), a locally adapted cassava variety, was 2.5-2.9 times smaller than those of the other varieties. Three of the four amylose samples, except that from M-hanatee, were very similar in average DP (4120-4390), chain length (530-550) and number of chains (7.1-7.5), and composed of nearly equal numbers of linear and branched molecules. The amylose from the M-hanatee variety showed a unique characteristic: it had smaller size (2050), shorter chain length (450), fewer chains (4.7) and a higher content of linear fraction (58%), when compared with other amyloses.
TL;DR: In this article, the use of trifluoroacetic anhydride as a promoter for the acylation of granular starch is reported, and the product is an acylated starch with degrees of substitution (DS) of 2 to 3, as analyzed by gas-liquid chromatography or high-pressure liquid chromatography.
Abstract: The use of trifluoroacetic anhydride as a promoter for the acylation of granular starch is reported. Efficient acylation in a homogeneous solution is attained when the carboxylic acid of interest and trifluoroacetic anhydride are added, the latter in at least twice molar excess to the hydroxyl groups of the anhydroglucose residues. The reaction necessitates prior heating of granular starch in acetic acid before the acylation reagent is added. The product is an acylated starch with degrees of substitution (DS) of 2 to 3, as analyzed by gas-liquid chromatography or high-pressure liquid chromatography. Lower molar ratios of trifluoroacetic anhydride to the anhydroglucose residue gave lower degree of substitution. Additionally, starch acetates with different degree of substitution are prepared by addition of limited amounts of the acylation reagent or by partial de-acetylation of starch triacetate with sodium methoxide. Starch esters are prepared from acetic, butanoic, hexanoic, octanoic, palmitic and benzoic acids.
TL;DR: In this article, six types of starch microparticles were investigated and characterized, and it was concluded that the quality of the starch microspheres was influenced by molecular properties of starch material as well as type of buffer, and these factors were related to recrystallization kinetics, amount and quality of ordered/crystalline structure of final starch micro spheres and their microscopic appearance.
Abstract: Starch microparticle is a dosage form suitable for encapsulation of protein drugs. The microparticle characteristics can be influential factors for consecutive sustained drug release from the starch matrix and impact its ability to be coated by poly(D,L-lactide-co-glycolide). In this study, six types of starch microparticles were investigated and characterized. Desired qualities of the microspheres such as spherical form of the particles, well-defined and sharp particle contours were coincident with coarse surface morphology, sharp and distinct peaks in DSC and X-ray graphs. It was concluded that the quality of the starch microparticles was influenced by molecular properties of the starch material as well as type of buffer, and these factors were related to recrystallization kinetics, amount and quality of ordered/crystalline structure of final starch microspheres and their microscopic appearance.
TL;DR: In this article, X-ray diffraction, light scattering and chain length determination were used to determine molecular characteristics of makal starch from a non-conventional source, where the granules had an oval shape with sizes between 8 and 20μm, with an average size of 12.4 μm.
Abstract: Starch was isolated from a non-conventional source: makal (Xanthosoma yucatanensis) and molecular characteristics were determined using X-ray diffraction, light scattering and chain length determination. The granules had an oval shape with sizes between 8 and 20μm, with an average size of 12.4 μm. Amylose content was 22.4% and amylopectin content 77.6%. The granules presented a C-type X-ray diffraction pattern, with a degree of polymerization (DP) of 5-19 for branch chain lengths and an average molar mass of 5.4 × 10 6 g/mol. The R H and the R G was 61.7 and 92.7 nm, respectively. Gelatinization temperature was 72.6 to 84.2°C and transition enthalpy was 15 J/g, which may be related to the X-ray diffraction pattern and to the small granule size of makal starch. The retrogradation of makal starch increased during storage.
TL;DR: In this article, a high-resistant starch (RS) rice (RS111) was compared to that of a wild rice type (R7954), which exhibited high RS content and incomplete starch hydrolysis in both cooked rice and rice flour.
Abstract: Starch digestibility and starch structure of a high-resistant starch (RS) rice (RS111) was compared to that of a wild rice type (R7954). RS111 exhibited high RS content and incomplete starch hydrolysis in both cooked rice and retrograded rice flour. High IRS rice RS111 had a higher lambda(max) of absorbance and blue value of iodine-binding starch complex and contained a higher percentage of intermediate chains of amylopectin than R/954. X-ray diffraction pattern of IRS isolated from cooked high IRS rice displayed a mixture of B- and V-type that was more resistant to starch hydrolysis by alpha-amylase. Resistant starch in RS111 is composed mainly of linear amylose and some low-molecular-weight amylopectin.
TL;DR: In this paper, the effect of different jet cooking temperatures in the range 110 degrees C - 140 degrees C was studied in an excess steam jet-cooker, where AsFIFFF was combined with multi-angle light scattering (MALS) to investigate how molar mass, root-mean-square (r.m.s.) radius and shape was influenced by different conditions of jet cooking.
Abstract: Asymmetrical flow field-flow fractionation (AsFIFFF) in combination with multi-angle light scattering (MALS) was applied to cationic potato amylopectin (CPAP) to investigate how molar mass, root-mean-square (r.m.s.) radius and shape was influenced by different conditions of jet-cooking. The effect of different jet-cooking temperatures in the range 110 degrees C - 140 degrees C was studied in an excess steam jet-cooker. This equipment is used in the industry for dissolution of starch and starch derivatives before technical application. The effect of different ionic strengths conditions was examined in the range of 10-200 mM. The weight-average molar mass decreased from about 34 x 10(7) g/mol to 2.6 x 10(7) g/mol when the jet-cooking temperature was increased from 110 degrees C to 140 degrees C. Concurrently the root-mean-square radius decreased from ca 380 nm to 90 nm. The decrease in size was reflected by a decrease in viscosity with increasing temperature. The root-mean-square radius was reduced when increasing the ionic strength. This decrease in size was correlated with a decrease in viscosity. Conformation and Kratky plots showed that at low ionic strength (<= 10 mM) CPAP behaved as a flexible chain with high degree of branching, close to hyperbranching. Increase of the ionic strength gave a more compact structure and changes in the internal structure were observed as well. Consequently, by using AsFIFFF - MAILS the effect of technical processing on the molar mass, molecular radius, conformational structure, and shape could be determined in a size region where standard methodology commonly fails. (Less)