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Highlights: [•] STMP crosslinked porous starch was produced by crosslinking and partial enzymatic hydrolysis. [•] Crosslinking with STMP increased the integrity of starch which resulted into lower swelling power. [•] First order kinetics model predicted the adsorption kinetics data of crosslinked porous starch well. [•] Different degree of crosslinking altered the interior structure of porous starch and increased crystallinity. [•] Porous starch crosslinked with 6% STMP possessed better stability against heat and shear. [ABSTRACT FROM AUTHOR]

Highlights: [•] Starch-flaxseed meal (FM) composite films were prepared by solution casting. [•] Dynamic mechanical and tensile properties, Tg , WVP of these films were determined. [•] Storage modulus of these starch–FM films decreased as the temperature increased. [•] Tg and tensile strength of these FM-films increased with the increase in FM content. [•] WVP of these starch–FM films decreased significantly at >5% FM content. [Copyright &y& Elsevier]

Abstract: Crosslinked starch microspheres (CSMs) were prepared using a novel two-stage water-in-water emulsion method (WWEM). The results show that the yield and crosslinking density of CSMs were affected significantly (p <0.05) by molecular weight and concentration of polyethylene glycol (PEG) in continuous phase, crosslinker concentration as well as incubation time. The increase in any one of these variables resulted into increase in the crosslinking density. The yield and crosslinking density of CSMs prepared by WWEM (WWEM-CSMs) were lower than those prepared by water-in-oil emulsion method (WOEM). The morphology, chemical composition and amorphous/crystalline nature of the CSMs were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). SEM analysis indicated that the WWEM-CSMs were spherical, compact and nonporous in nature. FTIR and XRD analysis indicated that WWEM-CSMs were PEG-free and amorphous in structure. These characteristics were very similar to the characteristics of CSMs prepared by WOEM. [Copyright &y& Elsevier]

Abstract: Rheological properties of the extruded pastes of various extrusion conditions were investigated by dynamic oscillation and creep-recovery tests. Temperature sweep test showed that the starch gelatinization of non-extruded pastes took place at about 67°C and no gelatinization was observed for the extruded sample. Frequency sweep tests could be represented by a Power law model and the samples showed gel-like behavior since storage modulus was much larger than loss modulus. The creep-recovery data were modeled by the Burger’s model. With the addition of flaxseed, the viscoelastic modulii of pastes were increased due to the formation of starch–protein–fat network, however, with further increasing the flaxseed content the viscoelastic modulii of pastes were decreased due to excessive fat which lead to network weakening. The water holding capacity results indicated that the viscoelastic properties of pastes were depended on the swelled starch–protein complex granules and the formation of new cross-links in the network. [Copyright &y& Elsevier]

Abstract: Rheological properties of flaxseed mucilage under different extrusion conditions with or without enzyme treatment were studied. The steady-shear tests indicated that the apparent viscosity of flaxseed mucilage fitted well to Power law model and all samples showed a shear-thinning behavior. The consistency index decreased and the flow behavior index increased with an increasing temperature and a decreasing screw speed. The addition of initial moisture content improved the degradation of flaxseed mucilage while further increase affected the action negatively. The empirical equations describing relationships between parameters of rheological models and extrusion factors were obtained. The results showed that extrusion can damage the compact fiber structure which improved the effect of enzyme treatment. The apparent viscosity decreased with the increase in hydrolyzing time and enzyme loading amount. [Copyright &y& Elsevier]

Abstract: The relaxation, creep, temperature-dependence and frequency-dependence characteristics of sweet potato roots were evaluated using a dynamic mechanical analyzer (DMA). The sweet potato was cut into rectangular to meet the testing requirements and wrapped with sealing film or aluminum foil to prevent water loss. The temperature scanning tests were carried out at 2°C/min and 10°C/min in the temperature range of 30–100°C, and the frequency sweep tests were conducted in a range of 50–0.1Hz. The regression results suggested that 5-element Maxwell model described relaxation behavior better for consisting of two relaxation times; the creep behavior matched the Burgers model well, and changes in creep parameters were observed after each creep cycle. The temperature scanning tests revealed that starch gelatinization was only obtained when the temperature increased at 2°C/min. A resonance frequency was detected both in 3-point bending and compression deforming clamps. [Copyright &y& Elsevier]

Abstract: The granule morphology, microstructure, and thermal properties of micronized cassava starch prepared by a vacuum ball-grinding machine were investigated. Scanning electron microscopy (SEM) analysis indicated that the morphology of starch granule changes during the ball-grinding treatment. Differential scanning calorimetry (DSC) analysis indicated that the maximum peak temperature (T p) of the gelatinization process, the glass transition (T g), and peak height index (PHI) for the starch granules decreased when the size of micronized starch granules was reduced. When the size of starch granules was reduced beyond 9.11μm, they have a tendency to agglomerate and their ΔH were increased. The granule size has a significant effect on the gelatinization properties of cassava starch. This study will provide useful information of the micronized starch for its potential industrial application. [Copyright &y& Elsevier]

Abstract: Flaxseed gum solutions were extracted and dried by different methods: ethanol precipitation, freeze drying, 105°C oven drying, 80°C oven drying, spray drying, and vacuum drying. The effects of these drying methods on the rheological properties of flaxseed gum were investigated in present study. Ethanol precipitation increased the apparent viscosity of flaxseed gum solution, while all the other methods decreased the apparent viscosity. Most of the drying methods slightly increased the activation energy, except ethanol precipitation. In frequency sweep test, all the drying methods reduced the G′ and G″ values. In creep–recovery tests, the data were modeled by Berger’s model. The E 2 and η 1 values were reduced by all of the drying methods in this study. Some relationships were found between the parameters in the Power Law model of the frequency sweep test and the parameters in Berger’s model. [Copyright &y& Elsevier]

Abstract: Common buckwheat (Fagopyrum esculentum Moench) flour is widely used in food products due to its desirable taste, textural structure and nutrients. The effect of water content varying from ∼20% to ∼80% on the thermal behaviors of common buckwheat flour and its isolated starch was investigated by differential scanning calorimetry (DSC) from 40.0°C to 105.0°C and from −60.0°C to 160.0°C. The gelatinization temperature of buckwheat flour was between 60°C and 85°C and it decreased while the water content increased. Isolated buckwheat starch showed a narrower gelatinization range from 60°C to 75°C. T o, T p, T c and ΔH of the ice melting peak of buckwheat flour and starch in the second scan increased as the water content increased. Their viscosity, crystallinity and retrogradation were also analyzed. [Copyright &y& Elsevier]

Abstract: Rheological properties of 5% (w/w) waxy maize starch (WMS)/xanthan gum (XG) mixed pastes (mixing ratios: 10/0, 9.5/0.5, 9/1) in the presence of sucrose (0%, 15%, and 30%) were studied. The 5% WMS paste displayed strong anti-thixotropic behavior based on the heating method adopted (heating in water bath for 40min with mixing at 200rpm). The addition of XG could accelerate the formation of new structure of the WMS/XG mixed pastes under shear conditions, and XG could also decrease the in-shear recoveries of the mixtures. Both the addition of XG and sucrose increased the apparent viscosity (η a) and dynamic moduli (G′ and G″) of the mixed pastes, with XG contributing to the solid-like properties of the mixtures obviously, while sucrose played a contrary role. Thermostable properties of the mixed pastes could be improved distinctly with the addition of XG, whereas sucrose decreased it slightly. [Copyright &y& Elsevier]

Abstract: Starch-based microparticles were prepared by emulsion crosslinking method, using trisodium trimetaphosphate (TSTP) as crosslinking agent. The prepared TSTP-crosslinked starch microparticles (TSMs) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) technique. SEM pictures showed smooth face and spherical shape for the TSMs. XRD patterns revealed that TSMs were of amorphous structure mostly. This result was confirmed by FTIR spectra. Influence of crosslinking density on particle size, swelling degree and loading capacity of TSMs was studied by varying TSTP concentration. It was found that with increasing TSTP concentration from 0.1 to 0.4g/g, the particle size and loading capacity increased, but swelling degrees showed a bell-shaped dependence on TSTP concentration with maximum values at the concentration of 0.2g/g in different media. However, the changes of these three aspects became inconspicuous when TSTP concentration increased to 0.4g/g. It is estimated that the crosslinking density had nearly reached its full extent at such concentration. The present investigated TSMs could potentially be applied in dry powder form for food ingredients delivery. [Copyright &y& Elsevier]

Abstract: In this study, starch-based microparticles (MPs) fabricated by a water-in-water (w/w) emulsification-crosslinking method could be used as a controlled release delivery vehicle for food bioactives. Due to the processing route without the use of toxic organic solvents, it is expected that these microparticles can be used as delivery vehicles for controlled release of food bioactives. Octenyl succinic anhydride (OSA) starch was used as raw material. Optical microscopy showed OSA starch-based microparticles (OSA-MPs) had a good dispersibility. Scanning electron microscopy (SEM) showed OSA-MPs had a solid structure and spherical shape. X-ray diffraction (XRD) patterns revealed that OSA-MPs were of amorphous structure. A Plackett–Burman screening design methodology was employed to evaluate the effects of the process and formulation parameters on the particle size of OSA-MPs. Considering the statistical analysis of the results, it appeared that the OSA starch concentration (P =0.0146), poly(ethylene glycol) (PEG) molecular weight (P =0.0155), volume ratio of dispersed phase/continuous phase (P =0.0204) and PEG concentration (P =0.0230) had significant effect on particle size. [Copyright &y& Elsevier]

Abstract: Rheological characteristics of potato starch/flaxseed protein concentrate composites were investigated using a rheometer. Effects of starch/protein mass ratio (0.2–1.0) and different cooling rate (2°C/min, 4°C/min and 6°C/min) on rheological behavior of composites were studied. The study showed that G’ and G’’ increased with increase of starch mass ratio in the temperature range of 40–95°C, in both heating and cooling process. The composites exhibited similar and , higher than those of potato starch alone at 60.3°C. The result of frequency sweep of the composites at the end of the cooling at 25°C exhibited an elastic behavior at all test frequency ranges (0.06283–62.83rad/s). Study of cooling rate on rheological characteristic of composites exhibited an increase in the G’ and G’’ values with decrease of cooling rate, probably because of gel network having a stronger structure with more time for dynamic equilibration. [Copyright &y& Elsevier]

Abstract: The dynamic mechanical properties of prepared maize and potato starch films were evaluated for mixtures containing 0%, 10% and 15% (w/w) of sucrose at temperatures ranging from 40.0 to 140.0°C. The spectra of storage modulus (G′), loss modulus (G″), and loss factor (tan δ) of starch films were acquired. Remarkable reduction in the glass transition temperature of maize and potato starch films was observed with the increasing sucrose content. The spectra of storage modulus (G′), loss modulus (G″), and loss factor (tan δ) were measured for the second and third time after two and seven days, respectively. The peaks of loss factor (tan δ) appeared at 59.81±1.86°C and 95.96±1.67°C after two-day-storage, but only one peak appeared at 85.46±5.50°C after seven days. A shifting trend from higher to lower temperature for loss factor was observed after seven days. [Copyright &y& Elsevier]

Abstract: High-pressure homogenization induced thinning of potato and cassava starch paste was investigated. The starch slurries at a concentration of 2.0wt.% were heated at 90°C for 1h and then rapidly cooled in tap water. The cooled starch pastes were homogenized at various pressures ranging from 0 to 100MPa using a lab-scale high-pressure homogenizer. The influence of homogenizing pressure on the temperature, apparent viscosity, electrical conductivity, and percent light transmittance of homogenized starch pastes were determined. Temperatures of homogenized starch pastes increased linearly with the increase of the applied pressure, and the rate was 0.177°C/MPa and 0.186°C/MPa for potato and cassava starch pastes, respectively. After high-pressure homogenization, the apparent viscosities of the starch pastes decreased, while the percent light transmittances of them increased. However, the electrical conductivities of starch pastes were not affected by homogenization. [Copyright &y& Elsevier]

The effect of steam explosion pretreatment on biodegradation of lignin in wheat straw was studied in this paper. Through experiments and analysis, 0.8MPa operation pressure and 1:20 wheat straw to water ratio are optimum for destroying lignin and the maximum of lignin loss rate is 19.94%. After steam explosion pretreatment, the wheat straw was retted by Trametes versicolor for 40 days. Biodegradation rate of lignin was tested and the maximum of 55.40% lignin loss rate was found on day 30. During the whole process of both steam explosion pretreatment and biodegradation, 75.34% lignin was degraded, without steam explosion the biodegradation of raw material the degradation rate of lignin was 31.23% only. FT-IR spectroscopy, TGA and SEM were used for further validating the results of biodegradation. [Copyright &y& Elsevier]

Abstract: Influences of alfalfa powder concentration and granularity on the dynamic rheological properties of alfalfa-wheat dough was studied. Frequency sweep tests at 25°C and 80°C and temperature sweep tests from 25°C to 80°C were applied to wheat dough samples. Elastic moduli (G′) and viscous moduli (G″) of the alfalfa-wheat dough at 80°C were higher than those of the alfalfa-wheat dough at 25°C. The viscoelastic moduli (G′ and G″) of the alfalfa-wheat dough at 80°C showed less frequency dependence compared to those of the samples at 25°C. The viscoelastic moduli (G′ and G″) of alfalfa-wheat dough increased with the increasing of alfalfa powder concentration from 0% to 10% and decreased with further increase in alfalfa powder concentration from 10% to 20% at 25°C. All the alfalfa-added samples showed a delay in the dough gelatinization temperature comparing with the control sample. On the other hand, the viscoelastic moduli (G′ and G″) increased with the increase of alfalfa powder granularity distributed from 80–100 to 40–60 mesh. [Copyright &y& Elsevier]

Abstract: The effects of starch concentration on the rheological properties of dilute aqueous solutions of cassava starch were investigated. Cassava starch suspensions at different starch concentrations (0.2, 0.4, 0.6, 0.8, and 1.0 wt. %) were heated at 90°C for 1h and then rapidly cooled to 25°C. The apparent viscosities of starch solutions were measured as a function of starch concentration. The cassava starch solution with a concentration of 0.2% showed Newtonian behavior, and as the concentration was increased beyond 0.4%, the solutions showed shear-thinning behavior. The flow behavior (apparent viscosity against shear rate) of the solutions was well described using a power law model. The consistency indices increased and the flow behavior indices decreased with the increasing of starch concentration. After storing the solutions at 25°C for 24h, precipitation of starch took place instead of gelation. The volume of precipitation bed increased linearly with starch concentration. [Copyright &y& Elsevier]

Abstract: Crosslinked anionic starch microspheres were prepared with sodium trimetaphosphate (STMP) as crosslinking agent through 5h w/o emulsification-crosslinking reaction at 50°C. Laser diffraction technique and scanning electron microscopy revealed that microspheres had narrow size distribution, good sphericity and fine dispersibility. In addition, drug loading and releasing properties were investigated with Methylene Blue as a model drug on the basis of single-factor study. It was found that the loading ratio of MB was significantly influenced by loading time, dissolution medium, loading temperature as well as MB concentration (P <0.05). Either the increase of loading time or drug concentration could lead to the increase of drug loading amount of microspheres, however, drug loading amount reached its maximum in NaCl (0.9%) dissolution medium at room temperature. Furthermore, the release profile contained two main expulsion processes: an initial burst release followed by a sustained swelling-controlled release. [Copyright &y& Elsevier]

Abstract: Both small amplitude oscillatory and steady shear measurements were carried out at 25°C, 50°C, and 75°C in order to determine the rheological properties of the mixtures of flaxseed gum (0.1–0.5%) and native maize starch (3%). It was found that the apparent viscosities of the samples increased with the increasing of flaxseed gum concentration. The apparent viscosities of the samples were fitted well to the power law model (the values of R 2 were between 0.954 and 0.999). The consistency index (K) of the gum–starch mixtures increased with the increasing of flaxseed gum concentration. The gum–starch mixtures showed gel-like behavior since the storage modulus (G′) was much larger than the loss modulus (G″) and the frequency dependence of both modulus was not significant. The G′ and G″ of the gum–starch mixtures was increased with the increasing of flaxseed gum concentration. The influence of temperature was more significant for the flaxseed gum–maize starch mixtures compared to maize starch gel. [Copyright &y& Elsevier]

Abstract: Maize starch–water suspensions (1.0%) were subjected to single-pass high-pressure homogenization treatment at 60MPa, 100MPa, and 140MPa. The structure and thermal properties of the high-pressure homogenized starches were investigated using DSC, X-ray diffraction technique, laser scattering, and microscope, with native maize starch (suspended in water, but not homogenized) as a control sample. DSC analysis showed a decrease in gelatinization temperatures (T o, T p) and gelatinization enthalpy (ΔH gel) with increasing homogenizing pressure. No noticeable effect of high-pressure homogenization on the retrogradation of maize starch was observed. Laser scattering measurements of particle size demonstrated an increase in the granule size at a homogenizing pressure of 140MPa. This was attributed to the gelatinization and aggregation of the starch granules. X-ray diffraction patterns showed that there was an evident loss of crystallinity after homogenization at 140MPa. Microscopy studies showed that the maize starch was partly gelatinized after high-pressure homogenization, and the gelatinized granules were prone to aggregate with each other, resulting in an increase of granule size. [Copyright &y& Elsevier]

Abstract: Flaxseed is a good source of plant protein for both human diet and animal feed. Extrusion process effectively improves the digestion of flaxseed. In the present work, the effects of extrusion parameters such as screw speed, moisture content, temperature and feed rate on the IVPD of the extruded flaxseeds were investigated. A central composite design was used with four controlled variables: screw speed (70, 120, 170, 220 and 270r/min); moisture content (4%, 10%, 16%, 22% and 28%); temperature (84, 108, 132, 156 and 180°C); and feed rate (25.4, 47.4, 69.4, 91.4 and 113.4kg/h). The experimental values of IVPD measured from 69.46% to 77.43%. A second-order model was obtained to predict the IVPD. It has been found that moisture content and feed rate affect the IVPD more significantly compared with the temperature and screw speed. In the present study, the maximum digestibility was obtained when the screw speed, moisture content, temperature and feed rate were 120r/min, 10%, 120°C and 91.4kg/h, respectively. The application of this analysis method for optimizing the extrusion process of flaxseeds is discussed. [Copyright &y& Elsevier]