•Corn starches were acid hydrolyzed and heat-moisture treated in two sequences.•The sequence of dual treatments deeply affects the physicochemical properties.•Acid hydrolysis after heat-moisture treatment results in more thermostable starches.•Perfection and destruction do vary during different stages of dual modifications.Dual modification of corn starch was carried out by combining acid hydrolysis (AH, 6, 12, 24 h) and heat-moisture treatment (HMT, 15, 30, 60 min) in different sequences (AH-HMT and HMT-AH). X-ray diffractometry, differential scanning calorimetry, polarized light microscopy, and rheometer were used to characterize the differences in molecular structure and physicochemical properties resulting from the sequences. Both AH-HMT and HMT-AH sequences increased the metastability of the starch granules. Starch hydrolyzed by AH for 12 h and then subjected to HMT for 15 min (AH12-HMT15) has onset, peak, and conclusion gelatinization temperatures that were 4.2, 3.9 and 6.4 °C higher than those of HMT15-AH12 one, respectively. The relative crystallinity of HMT15, 30-AH decreased as AH time increased; however, it increased in the HMT60-AH sample. Besides, all the temperature ranges of gelatinization of AH-HMT15, 30 were higher than those of HMT15, 30-AH, but lower in the case of AH-HMT60 when compared to HMT60-AH. This indicates that the perfection effect became more prominent over destruction on HMT60 for AH-HMT samples. The AH-HMT sequence also resulted into lower relative crystallinity, swelling power, solubility, gelatinization enthalpy, and pasting viscosity than in those samples produced using HMT-AH sequence.

•LBG significantly changes the rheological and microstructural properties of SPI gel.•Creep/recovery rate and elasticity increases with LBG addition.•SPI-LBG gel shows a typical Type I network behavior in LAOS test.•LBG addition lowered the strain amplitude at which the non-linear behavior occurs.•Presence of LBG increased the volume of pore between protein networks.The effect of the addition of locust bean gum (LBG) on the rheological properties, microstructure and fractal dimension of glycono-δ-lactone induced soy protein isolate (SPI) gels were studied (LBG concentration = 0.01%–0.04%, SPI concentration = 6%). Both the small and large amplitude oscillatory shear measurements were carried out to characterize the rheological properties of SPI and SPI-LBG gels. The G′ of SPI-LBG gels was highly frequency dependent within the frequency range of 6.28 rad/s to 62.8 rad/s. Fourier transform rheology was used to analyze the higher harmonic signals from nonlinear stress waveform. SPI-LBG gels showed typical Type I network behavior similar to that of SPI gel at strain amplitude >2% in LAOS tests. Creep/recovery tests showed that the addition of LBG increased both the elastic and viscous moduli of SPI-LBG gels. The image of the microstructure captured by confocal laser scanning microscopic (CLSM) was used to determine the fractal dimension. The protein network structure of SPI-LBG gels showed greatly bigger pore volume, better scale behavior than SPI gels, and the chaos and complexity of the protein aggregates in SPI-LBG gels were much less than that in SPI gel. LBG was found to play an important role in a SPI-LBG gel system.

•Increase in the moisture content expands the maize kernel's cellular structure.•X-ray diffraction pattern of maize powder was identical to that of maize starch.•Burgers model can adequately represent the creep behavior of the maize kernel.•5-Element model better predicts the relaxation behavior than 3-element model does.•Tg values in maize kernels decreased with increase in the moisture content.The creep recovery, stress relaxation, temperature-dependence and their frequency-dependence of maize kernel were determined within a moisture content range of 11.9% to 25.9% (w/w) by using a dynamic mechanical analyzer. The 4-element Burgers model was found to adequately represent the creep behavior of the maize seeds (R2 > 0.97). The 5-element Maxwell model was able to better predict the stress relaxation behavior of maize kernel than the 3-element Maxwell model. The Tg values for the maize kernels decreased with increased moisture content. For example, the Tg values were 114 °C and 65 °C at moisture content values of 11.9% (w/w) and 25.9% (w/w), respectively. The magnitude of the loss moduli and loss tangent and their rate of change with frequency were highest at 20.7% and lowest at 11.9% moisture contents. The maize kernel structure exhibited A-type crystalline pattern and the microstructure was found to expand with increase in moisture content.

•Both G and M1 endotherms were observed in S25 in the moisture content range of 40–60%.•Only M1 endotherm was observed in S64, S68 and S70 in the entire moisture content range.•Melting temperature of M2 endotherm in S70 was the highest at moisture contents 40%.•S64 with lower gelatinization degree had higher amount of unfreezable water.•S68 and S70 with higher gelatinization degree had lower amount of unfreezable water.The effect of moisture content on the interactions between water and partially gelatinized starch during gelatinization process was investigated. The interactions were probed using differential scanning calorimetry (DSC). The starch samples were partially gelatinized at 25 °C (S25), 64 °C (S64), 68 °C (S68) and 70 °C (S70) and the moisture contents were varied from 25% to 78% (w/w). The G endotherm was not observed and only the M1 endotherm was observed in S64, S68 and S70 in the entire moisture content range. The G endotherm was not observed and only the M1 endotherm was observed at higher peak temperature in S25 when the moisture content was below 30% (w/w). The melting temperature of M2 endotherm in S70 was the highest among all the samples tested in the entire moisture content range. At water content > 30% (w/w), S68 and S70 had lower amount of unfreezable water, while S64 had higher amount of unfreezable water.

•Cellulose nanofibers were extracted from de-pectinated sugar beet pulp.•We combined chemical treatments and high pressure homogenization.•The diameter of the obtained cellulose nanofibers was from several nm to 70 nm.•The crystallinity of nanofibers increased significantly after treatments.•Potential for future application in biocomposite material.Cellulose nanofibers (diameter = 10–70 nm) were produced using chemical treatments (alkali treatment and bleaching) and high pressure homogenization from de-pectinated sugar beet pulp (DSBP). Chemical analysis and Fourier transform infrared spectroscopy (FTIR) indicated that the chemical treatments greatly removed the hemicellulose and lignin from the DSBP and significantly increased the cellulose content. The crystallinity of the cellulose nanofibers increased from 35.67% to 69.62% after alkali treatment and bleaching. The thermal degradation temperature of DSBP cellulose nanofibers was 271.7 °C which was found to be 47.3 °C higher than that of the untreated DSBP. The DSBP cellulose nanofibers can be preferably used as reinforcement in the biocomposite material at high temperature.

•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.Crosslinked porous starch samples were produced by first crosslinking corn starch with sodium trimetaphosphate (STMP) and then partially hydrolyzing it with a mixture of α-amylase and glucoamylase. The granule morphology, porosity, swelling power, adsorption capacity, crystalline nature, molecular structure, melting and viscometric properties of these starch samples were measured and analyzed. The results showed that the porous starch which was crosslinked with 6% (w/w) STMP (ScPS-6) possessed remarkable superiority in terms of thermal and shear resistance among all the starch samples tested. The ScPS-6 also had the highest porosity and largest average pore diameter values. The swelling power of crosslinked porous starch was 56.3% lower than that of uncrosslinked porous starch. First order reaction kinetics equation was found to excellently (R2 ≥ 0.99, average error = 6.03%) predict the experimental adsorption kinetics data of methylene blue for the crosslinked porous starch samples.

We report, for the first time, the preparation method and characteristics of starch films incorporating spray dried and vacuum freeze dried starch nanoparticles. Physical properties of these films such as morphology, crystallinity, water vapor permeability (WVP), opacity, and glass transition temperature (Tg) and mechanical properties (strain versus temperature, strain versus stress, Young's modulus and toughness) were measured. Addition of both starch nanoparticles in starch films increased roughness of surface, lowered degree of crystallinity by 23.5%, WVP by 44% and Tg by 4.3 °C, respectively compared to those of starch-only films. Drying method used in preparation of starch nanoparticles only affected opacity of films. The incorporation of nanoparticles in starch films resulted into denser films due to which the extent of variation of strain with temperature was much lower. The toughness and Young's modulus of films containing both types of starch nanoparticles were lower than those of control films especially at <100 °C.Highlights► Starch films were produced by adding spray and vacuum freeze dried starch nanoparticles. ► Presence of starch nanoparticles increased film roughness lowered the crystallinity, WVP and Tg. ► Presence of freeze dried starch nanoparticles in film increased the film opacity. ► Presence of starch nanoparticle enhanced film compactness and resistance against shrinkage. ► Presence of starch nanoparticles lowered the Young's modulus and toughness at <100 °C.

Starch films were successfully produced by incorporating spray dried and vacuum-freeze dried starch nanoparticles. The frequency sweep, creep-recovery behavior and time–temperature superposition (TTS) on these films were studied. All these films exhibited dominant elastic behavior (than viscous behavior) over the entire frequency range (0.1–100 rad/s). The incorporation of both types of starch nanoparticles increased the storage and loss modulus, tan δ, creep strain, creep compliance and creep rate at long time frame and reduced the recovery rate of films while the effect of different kinds of starch nanoparticles on these parameters was similar both in magnitude and trend. TTS method was successfully used to predict long time (over 20 days) creep behavior through the master curves. The addition of these nanoparticles could increase the activation energy parameter used in TTS master curves. Power law and Burger's models were capable of fitting storage and loss modulus (R2 > 0.79) and creep data (R2 > 0.96), respectively.Highlights► Starch films showed dominant elastic behavior (than viscous behavior) in 0.1–100 rad/s range. ► Addition of starch nanoparticle increased storage and loss moduli, loss angle of starch films. ► Starch nanoparticles increased creep strain, compliance and rate but reduced recovery rate. ► TTS predicted higher activation energy in long-term creep of films containing nanoparticles. ► Power law and Burger's models predicted the frequency sweep and creep behavior data well.

•Retrogradation enthalpy of all starch samples increased with storage time.•S25 and S64 had A-type crystalline pattern while S68 and S70 showed B-type pattern.•Avrami model fits the retrogradation kinetics data of these starches reasonably well.•The growth of remainder crystals in starch granules was faster in S25 and S64.•The nucleation and growth rates of newly formed crystals were faster in S68 and S70.The objective of this work was to investigate the effect of partial gelatinization of starch on its retrogradation using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. The Avrami equation was used to predict the evolution of starch retrogradation kinetics. The degree of retrogradation in starch samples partially gelatinized 64 °C (S64), 68 °C (S68) and 70 °C (S70) and control (S25) increased with storage time. The retrogradation enthalpies of S68 and S70 were almost four times as high as that of S64. The S25 and S64 had dominant A-type crystalline pattern while S68 and S70 showed dominant B-type crystalline pattern. The growth of remainder crystals was faster in S25 and S64, while both the nucleation and growth rates of new crystals were faster in S68 and S70. The Avrami model was found to represent the retrogradation kinetics data of these partially gelatinized starch samples quite satisfactorily (R2 > 0.95).

A central composite design was employed to determine the optimum extraction condition to obtain higher yield, better color attribute as well as better rheological and emulsifying properties in pectin extracted from sugar beet pulp (SBP). A second-order polynomial model was developed for predicting the yield of sugar beet pulp pectin (SBPP) based on the composite design. Response surface methodology (RSM) was used to quantify the integral effect of three processing parameters (extraction temperature, time and pH) on yield, yield stress, color attribute (tint value) and emulsifying activity index (EAI). Through the frequency analysis it was found that the optimal temperature, time and pH value of the extraction were 93.7 °C, 3 h, and 1.21, respectively. The yield, yield stress and tint value of the SBPP extracted at the optimal condition were 24.45%, above 0.1 Pa and −6.0, respectively.Highlights► Extraction process of sugar beet pulp pectin (SBPP) on yield, yield stress and tint has been optimized. ► The yield, color, rheological and emulsifying properties of SBPP were measured. ► The flow behavior of SBPP solution followed the Herschel–Bulkley model. ► RSM was used to quantify the integral effect of extraction temperature, time and pH. ► Optimum yield (24.45%), yield stress and tint value were obtained at 93.7 °C, 3 h and pH value of 1.21.

The effect of addition of NaCl on rheological properties of suspensions containing vacuum freeze dried starch nanoparticles was studied. These starch nanoparticles were produced through high pressure homogenization and emulsion cross-linking technique. Rheological properties such as continuous shear viscosity, storage and loss moduli and creep-recovery were measured. The presence of NaCl at concentration (5–15%, w/v) increased viscosity marginally (p > 0.05) while at 20% (w/v) it significantly (p < 0.05) increased viscosity. The presence of NaCl enhanced heat stability and weakened gelling capacity of suspensions. NaCl concentration below 15% (w/v) marginally (p > 0.05) increased the storage and loss moduli of suspensions. At 20% (w/v), NaCl increased both moduli significantly (p < 0.05) within frequency range tested (0.1–10 rad/s). Creep-recovery behavior was affected by NaCl and recovery rate was the highest (98.6%) at 20% (w/v) NaCl. The Cross, Power Law and Burgers’ models followed experimental shear viscosity, storage and loss moduli and creep-recovery data reasonably well (R2 > 0.94).Highlights► NaCl affected rheology of vacuum freeze dried starch nanoparticle (VFDSN) suspensions. ► The addition of NaCl was found to increase the viscosity of VFDSN suspensions. ► The presence of NaCl was found to restrain the gelling capacity of VFDSN suspensions. ► NaCl was found to significantly affect the storage and loss moduli of VFDSN suspensions. ► The 20% NaCl content in the VFDSN suspensions led to high (98.6%) creep-recovery.

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.Highlights► Crosslinked starch microspheres were prepared using a two-stage emulsion method. ► This method was found to be more energy efficient than w/o emulsion to prepare CSMs. ► The properties of CSMs prepared by these two methods were identical. ► Yield of CSMs obtained from w/w emulsion was lower that obtained from w/o emulsion. ► Crosslinking density of CSMs obtained from w/w emulsion was lower than w/o emulsion.

Both steady and large amplitude dynamic rheological testes were carried out in hydrothermally gelatinized waxy maize starch (WMS) pastes. The concentration of WMS was maintained at 6.0% (w/w) throughout these tests. The WMS pastes exhibited shear thickening behavior during the first up curve in steady shear tests. The shear thickening behavior was found to be irreversible and could not be retained after equilibrating the pastes beyond 6 h. The change in the shape of Lissajous curves was insignificant during strain sweeps at higher angular frequencies. This arose because of slow response of WMS pastes to oscillatory strain within a period of oscillatory shear, which can be attributed to the domination of rheological properties by amylopectin in continuous phase. High-pressure homogenization (HPH) was found to significantly reduce the apparent viscosity of the WMS pastes. After HPH, the WMS pastes behaved like typical Newtonian fluids.Highlights► Waxy maize starch (WMS) pastes display shear thickening behavior in shear tests. ► Structural change which causes shear thickening is irreversible upon equilibration. ► The shapes of Lissajous curves from strain sweeps are analyzed in this study. ► High-pressure homogenization (HPH) makes WMS pastes behave like Newtonian fluids. ► HPH significantly reduces apparent viscosity of the WMS pastes in this study.

Partially gelatinized starch was prepared by gelatinizing corn starch at 64–72 °C followed by spray drying (inlet temperature, feed flow rate, air flow rate of 200 °C, 7.2 ml/min and 0.375 m3/h, respectively). The morphology, granule size, crystalline fraction, swelling power and gelatinizing properties of partially gelatinized starch were investigated and compared with those of native starch. The surface morphology of partially gelatinized starch granules was shriveled with multiple surface folds. The granule size of partially gelatinized starch was smaller than that of native corn starch. There was either complete absence of crystalline fraction in partially gelatinized starch or the extent of crystalline fraction was greatly reduced. The swelling power of partially gelatinized starch was higher than that of the native starch below 60 °C, while it was lower than that of native starch above 60 °C. There was an increase in gelatinization temperature and a decrease in gelatinization enthalpy in partially gelatinized starch compared to that of native starch.Highlights► Partially gelatinized starch was prepared by gelatinization followed by spray drying. ► The crystalline fraction in partially gelatinized starch was greatly reduced. ► The swelling power of partially gelatinized starch was higher than the native starch <60 °C. ► Partially gelatinized starch had higher gelatinization temperature compared to the native starch. ► Partially gelatinized starch had lower gelatinization enthalpy compared to the native starch.

Starch nanoparticles prepared through high pressure homogenization and mini-emulsion cross-linking technology were successfully vacuum-freeze dried. Annealing process was introduced in the drying process and the cryoprotectants (lactose and mannitol) were used in the sample matrix. The effect of the annealing and cryoprotectants on the moisture content, glass transition temperature (Tg), amorphous/crystalline nature, particle size, morphology and the redispersibility of these nanoparticles was investigated. The residual moisture content of the nanoparticles was 4–9% (w/w) and it was lower in samples which were unannealed and contained cryoprotectants. Mannitol as cryprotectant resulted into starch nanoparticles with uniform spherical shape. The Tg of these nanoparticles varied from 52 °C to 57 °C and the difference was due to annealing and cryoprotectants. The annealing process and the presence of cryoprotectant did not hugely affect the X-ray diffraction pattern and FT-IR spectra which revealed the fully cross-linked and amorphous glassy state of starch nanoparticles.Highlights► Cross-linked starch nanoparticles were successfully obtained by vacuum-freeze drying. ► Annealing and cryoprotectant affected the drying process of starch nanoparticles. ► Morphology of starch nanoparticles was affected by annealing and cryoprotectants. ► Size of starch nanoparticles was affected by annealing and cryoprotectants. ► Redispersibility of starch nanoparticle was affected by annealing and cryoprotectants.

The effects of gum Arabic (GA) addition (0–4%, w/w) on stability of oil-in-water emulsion stabilized by flaxseed protein concentrate (FPC) and soybean protein concentrate (SPC) were studied. The result shows that emulsions stabilized by both proteins in the presence of the 2% gum Arabic (w/w) have better stability than its absence, by increasing the emulsion viscosity of the FPC stabilized emulsion and causing competitive adsorption between the GA and SPC layer to give a steric repulsion for the SPC stabilized emulsion, respectively. Then, the influences of ionic strength (0–200 mM NaCl) and temperature (25–95 °C for 20 min) on these emulsions in presence of GA were determined. The GA adsorbed at SPC-stabilized oil–water interface provided stability against NaCl concentration. In presence of GA, the SPC-stabilized emulsions also showed better stability at higher temperatures compared to the FPC-stabilized emulsions due to the denaturation of SPC and competitive adsorption between GA and SPC at higher temperatures.

The properties of starch-plasticizer (glycerol:xylitol = 1:1) dispersions obtained with and without high-pressure homogenization and their corresponding films were investigated. The fully gelatinized dispersions with or without homogenization were subsequently converted into films using solution casting. The apparent viscosity of the dispersions with or without homogenization was determined. The water vapor permeability, opacity, crystalline/amorphous nature, and mechanical properties of these starch-based films were determined. The high-pressure homogenization greatly reduced the apparent viscosity of the dispersions and altered the flow behavior from shear-thinning into Newtonian one. The films obtained from high-pressure homogenized dispersions had better moisture barrier property, better film transparency and higher tensile strength but lower elongation.

A new and convenient synthetic route using high-pressure homogenization combined with water-in-oil (w/o) miniemulsion cross-linking technique was used to prepare sodium trimetaphosphate (STMP)-cross-linked starch nanoparticles. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that starch nanoparticles had narrow size distribution, good dispersibility and spherical shape. Effect of process parameters (surfactant content, water/oil ratio, starch concentration, homogenization pressure and cycles) on the starch nanoparticle size in miniemulsion was evaluated. We show that there is an optimal surfactant concentration giving rise to smaller starch nanoparticles and better stability. Apart from the water/oil ratio and starch concentration, the homogenization pressure and cycles (passes) also significantly affect the size of starch nanoparticles (p < 0.05). The stability analysis of starch nanoparticles in water for 2 h to 2 days and in temperature ranges of 25–45 °C showed firm structure and good stability. These nanoparticles are expected to be exploited as drug carriers.

The effects of high pressure homogenization on the rheological properties of flaxseed gum solution were analyzed in this study. The apparent viscosity of flaxseed gum was decreased by increasing homogenization pressure, while the temperature of the solution was gradually increased at the same time. The consistency index and the flow behavior index in the Power Law model of apparent viscosity were also modeled with Power Law and logarithm equations, respectively. The decay in parameters of storage and loss modulus model was also found along with the increasing homogenization pressure. Although no effect of pressure on conductivity and gelling temperature was significant, the clarity of the flaxseed gum was increased by increasing pressure. The activation and zeta potential of the flaxseed gum showed similar trends with the homogenization pressure, which were first increased then decreased from 30 MPa.

The effects of pasting conditions, testing temperature, and shear rate on the anti-thixotropy of waxy maize starch (WMS) dispersions were investigated in this study. Activation energy and viscoelastic properties of the WMS dispersions were also determined to understand the anti-thixotropy of these dispersions. The WMS dispersions (5.0 wt.%) displayed both thixotropic and anti-thixotropic properties in loop and shear recovery tests, depending on pasting conditions and testing temperature. The standard anti-thixotropy test indicated anti-thixotropy of WMS dispersions only appeared at a certain shear rate range. When WMS dispersion was pasted more completely, the shear rate range for anti-thixotropy became wider, also the sample showed improved heat stability. The anti-thixotropy of the WMS dispersions was ascribed to re-range of the amylopectin molecules under appropriate shear rates. The normal maize starch (NMS) dispersion (5.0 wt.%) could not display anti-thixotropy here, due to a different paste structure formed by amylose in the continuous phase.

The effects of different drying methods (spray drying, freeze drying, vacuum drying, oven drying at 80 and 105 °C, and ethanol precipitation) on the color and functional properties such as zeta potential, foaming, gelling, and emulsion properties of flaxseed gum were studied. Spray dried powders had the lightest color among all the powders. The powder obtained from ethanol precipitation had the lowest zeta potential and the resultant emulsion was in the most stable state. The ethanol precipitated powders had the best emulsion capacity and stability, better than even the untreated samples. The oven dried (105 °C) powders had the best foaming capacity and the foam stability, while the 80 °C oven dried powder had highest gel strength among all the dried samples. These results will be helpful in selecting suitable drying method depending on the functional properties of the flaxseed gum powders.

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 50–0.1 Hz. 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.

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.

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 (Tp) of the gelatinization process, the glass transition (Tg), 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 9.11 μm, 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.

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 40 min with mixing at 200 rpm). 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 (ηa) 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.

High-pressure homogenization induced thinning of potato and cassava starch paste was investigated. The starch slurries at a concentration of 2.0 wt.% were heated at 90 °C for 1 h and then rapidly cooled in tap water. The cooled starch pastes were homogenized at various pressures ranging from 0 to 100 MPa 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.

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 E2 and η1 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.

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.

Crosslinked anionic starch microspheres were prepared with sodium trimetaphosphate (STMP) as crosslinking agent through 5 h 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.

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 1 h 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 24 h, precipitation of starch took place instead of gelation. The volume of precipitation bed increased linearly with starch concentration.

Flaxseed oil is the main component of the flaxseed and has many beneficial functions to human health. In this paper, the ultrasound-assisted extraction of oil from flaxseed is reported. The effects of some operating parameters such as ultrasonic power, extraction time, extraction temperature and solvent to solid ratio on the yield of flaxseed oil have been investigated and some of the results have been compared with that of conventional method. It has been found that ultrasound-assisted extraction requires a shorter extraction time and a reduced solvent consumption. The yield of flaxseed oil has been found to increase with the increase of the ultrasonic power and to decrease as the temperature is increased. Scanning electronic microscopy analysis was carried out on the flaxseed powder after the extraction. The images are powerful evidences to show the effect of ultrasound. The fatty acid compositions of the oils extracted by the ultrasound-assisted method and the conventional method have been analyzed using gas chromatography. It has been shown that the compositions of the flaxseed oils were not affected significantly by the application of ultrasound (p > 0.05). The ultrasound-assisted extraction may be an effective method for lipid production.

In this study, the extrusion detoxification technique on flaxseed was investigated by uniform design optimization. The effect of the temperature (°C), the feeding rate (kg h−1), the screw speed (rpm) and the moisture content (%) on the response value (the removal rate, %) of hydrocyanic acid (HCN) in flaxseed has been investigated. U12 (123 × 4) mixed-level uniform design was selected and the equation of extrusion detoxification model was obtained after 12 experimentations. The content of cyanide in flaxseed was determined by Association of Official Analytical Chemists (AOAC) method. The extrusion detoxification technique was optimized with stepwise non-linear regression analysis and response surface method (RSM). DPS Professional V.3.01 and MATLAB (Version 6.5.1) were used for data analysis. The optimized results, including the temperature, the feeding rate, the screw speed, the moisture content of flaxseed, the optimized value and the relative error of the model, were 146.0 °C, 32.7 kg h−1, 152.5 rpm, 12.5, 93.23 and 1.76%, respectively. In order to improve the productivity, the feeding rate can be increased to 60 kg h−1on condition that it can reach the demanding value of detoxification. At this feeding rate, the model value of the removal rate of HCN in flaxseed is 84.38%; the experimental value is 83.32%; the relative error of the model is 1.27%.

•Alkaline and high-pressure homogenization method extraction of bioactive components was studied.•Both alkaline and high-pressure homogenization can improve the extraction yield significantly.•Phenolic acids and flavonoids were identified from the extracts.•SEM and particle size were measured to analyze the mechanism.Phenolic acids were extracted from potato peels with NaOH treatment and a high-pressure homogenization (HPH) process. Total phenolic content, total flavonoid content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and extraction yield were determined with different treatment conditions. Significant improvement was observed after the alkaline and HPH treatments. HPLC analysis shows that the phenolic compounds contained gallic acid, sinapic acid, vanillic acid, syringic acid, protocatechuic acid, p-coumaric acid, chlorogenic acid, caffeic acid and ferulic acid. The yields of these specific phenolic acids varied with different treatments. Scanning electron microscope, nuclear magnetic resonance and particle size measurements suggest that changes in cellular structure may be the mechanisms for the improvement in extraction rendered by the HPH and NaOH treatments. In conclusion, the combined treatment of NaOH and HPH increased the extraction yield and functionality of the phenolic acids from the potato peel residues.Industry relevanceHigh-pressure homogenization as a process method has been applied widely in food industry. It can help with emulsification and sterilization significantly. But the potential of High-pressure homogenization as an assist method to improve the yield of extraction from food and food waste has not been developed. The positive effect of phenolic and flavonoids has been proved and found in potato peels. However, the release of these bioactive components is a difficulty with traditional method. The High-pressure homogenization can reduce the particle size apparently and release the bioactive compound. For potato peels, the production can be added into bread, meat, beverage, etc. to increase the fiber and nutrition. For other sorts of similar material, the high-pressure homogenization can be a novel to improve the extraction process of bioactive component bound in cell wall instead of inside the cell. In this article, we developed a new method with high-pressure homogenization and alkaline treatment to improve the extraction process dramatically. Meanwhile, the process can be scale up to industry with minor modification and adjustment.

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.

•Biphasic endotherms were both observed in DSC traces even in excess water.•Thermal transitions were interpreted well by starch swelling and dissolution theory.•The first endotherm was associated with the swelling of partially degraded starches.•The second endotherm was related to the dissolution of residual crystalline starch.•Heat-moisture treatment increased swelling power of prolonged hydrolyzed starch.The multiple thermal transitions of acid-hydrolyzed and heat-moisture treated corn starch samples in excess water were measured using differential scanning calorimetry (DSC) and interpreted using a polymer swelling and dissolution theory. The dual treatment of acid hydrolysis (AH) and heat-moisture treatment (HMT) with different extent of reaction generates starches with various degrees of residual crystalline structure. Multiple endothermic transitions (G and M1) were firstly observed in DSC traces even in excess water. In this study, the G and M1 endotherms were proposed to be related with the energy consumption associated with granule swelling and crystallites dissolution respectively. In contrast, only a single M1 endotherm transition from a broad to a sharp and narrow endotherm upon HMT was consistently observed for starch samples acid hydrolyzed for 48 and 72 h, which testified the dominance of rearrangement over the destruction upon HMT. This novel theory describing the multiple phase transition was also evidenced by the variation of swelling power and relative crystallinity.

•Biphasic endotherms were found in DSC curves under excess water conditions.•The first viscosity peak is regarded as unique feature during starch gelatinization.•Three-stage of swelling was identified by comparation analysis of gelatinization.•The first endotherm in DSC correlated well with the first viscosity peak.•The third-stage of swelling is a process without energy consumption.The gelatinization of corn starch was studied using differential scanning calorimetric (DSC) and rheological tests by the same heating rate (10 °C/min), temperature range (20–90 °C) and starch-to-water ratio (1 mg/10 mg). The corn starch was dually modified using acid hydrolysis (AH) followed by heat-moisture treatment (HMT) in AH-HMT sequence. The viscosity versus temperature was presented using semi-logarithmic coordinates to better demonstrate the viscosity peaks. A three-stage gelatinization of AH-HMT starches was identified through the comparative analysis of rheological and thermal properties. The first stage of gelatinization correlated with the G endotherm well (R2 > 0.9) and was an irreversible process; the second stage of gelatinization and concomitant disruption of the crystalline structure corresponded to the M1 endotherm, while the third-stage of gelatinization was found to be a process of water absorption without energy consumption (no endotherm). The correlation of characteristic temperature showed that the complex gelatinization process could be well explained by the multi-stage of gelatinization using comparative analysis. These findings also provided new evidence to clarify the mechanism underlying the G and M1 endotherms observed in DSC curves in excess water.

Maize starch–water suspensions (1.0%) were subjected to single-pass high-pressure homogenization treatment at 60 MPa, 100 MPa, and 140 MPa. 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 (To, Tp) and gelatinization enthalpy (ΔHgel) 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 140 MPa. 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 140 MPa. 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.