Characterization of non-linear rheological behavior of SPI-FG dispersions using LAOS tests and FT rheology
- Authors: Bi, Chonghao , Li, Dong , Wang, Li-jun , Wang, Yong , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 92, no. 2 (2013), p. 1151-1158
- Full Text: false
- Reviewed:
- Description: The effect of flaxseed gum (FG) on the rheological and nonlinear stress response behaviors of mixed soy protein isolate (SPI)-flaxseed gum (FG) dispersions were studied. Results showed that the viscosity of the SPI-FG mixed dispersions increased significantly with increase in the FG concentration. Both the shear stress and the apparent viscosity values as a function of shear rate were fitted well using Power law model as expected. The frequency dependence of G′, G′′ and tan δ of soy protein isolate decreased as the FG concentration increased. The large amplitude oscillatory shear (LAOS) test and Fourier transform (FT) rheology analysis showed that the addition of flaxseed gum strongly affected the structure of the SPI-FG mixed dispersion system as shown by deformation of the nonlinear stress response curve and significantly altered magnitude of higher harmonic curve. The addition of FG increased the instantaneous strain softening effect of the SPI-FG mixed dispersion system. © 2012 Elsevier Ltd.
- Description: 2003011034
Aggregation behavior in water of amphiphilic diblock copolymers bearing biocompatible phosphorylcholine and cholesteryl groups
- Authors: Ohno, Sayaka , Hasegawa, Shoto , Liu, Huihua , Ishihara, Kazuhiko , Yusa, Shin-ichi
- Date: 2015
- Type: Text , Journal article
- Relation: Polymer Journal Vol. 47, no. 1 (2015), p. 71-76
- Full Text: false
- Reviewed:
- Description: Poly(2-(methacryloyloxy)ethyl phosphorylcholine)-block-poly(cholesteryl 6-methacryloyloxyhexanoate) (PMPC 82 -b-PChM n) copolymers with different PChM block lengths were prepared via reversible addition-fragmentation chain transfer controlled/living radical polymerization using a PMPC-based macro-chain transfer agent. The subscript number and n (=3 and 6) refer to the degree of polymerization of the PMPC and PChM blocks, respectively. PMPC 82 -b-PChM n cannot dissolve in water directly due to the strong hydrophobic nature of the PChM block. To prepare the aqueous solution, the diblock copolymer was dissolved in an organic solvent and then dialyzed against pure water. These diblock copolymers formed spherical and rod-like micelles in water, depending on the composition of cholesteryl (Chol) group in the polymer. The prepared aggregates were characterized using static light scattering, dynamic light scattering, transmission electron microscopy and fluorescence probe techniques. The characterization results suggest that the morphology of the polymer aggregates can be controlled from spherical to rod-like micelles by increasing the number of Chol groups in the polymer.
Understanding the distribution of natural wax in starch-wax films using synchrotron-based FTIR (S-FTIR)
- Authors: Muscat, Delina , Tobin, Mark , Guo, Qipeng , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 102, no. 1 (2014), p. 125-135
- Full Text: false
- Reviewed:
- Description: High amylose starch–glycerol (HAG) films were produced incorporating beeswax, candelilla wax and carnauba wax in the presence and absence of Tween-80 in order to determine the distribution of wax in the films during the film formation process. The distribution of these waxes within the film was studied using Synchrotron based Fourier Transform Infrared Spectroscopy (S-FTIR) which provided 2D mapping along the thickness of the film. The incorporation of 5% and 10% wax in HAG films produced randomly distributed wax or wax-rich domains, respectively, within these films. Consequently, the addition of these waxes to HAG increased the surface roughness and hydrophobicity of these films. The addition of Tween-80 caused variations in wax-rich bands within the films. The HAG + carnauba wax + Tween-80 films exhibited domed wax-rich domains displayed with high integrated CH2 absorption value at the interior of the films, rougher surface and higher contact angle values than the other films. The S-FTIR 2D images indicated that the distribution of wax in starch–wax films correlated with the roughness and hydrophobicity of the starch–wax films.
Optimization of production yield and functional properties of pectin extracted from sugar beet pulp
- Authors: Lv, Cheng , Wang, Yong , Wang, Li-jun , Li, Dong , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 95, no. 1 (2013), p. 233-240
- Full Text: false
- Reviewed:
- Description: 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. © 2013 Elsevier Ltd.
- Description: 2003011020
Characterization of starch films containing starch nanoparticles Part 1: Physical and mechanical properties
- Authors: Shi, Aimin , Wang, Li-Jun , Li, Dong , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 96, no. 2 (2013), p. 593-601
- Full Text: false
- Reviewed:
- Description: 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. © 2012 Elsevier Ltd. All rights reserved.
- Description: C1
Physicochemical and functional characteristics of lentil starch
- Authors: Joshi, Matina , Aldred, Peter , McKnight, Stafford , Panozzo, Joe , Kasapis, Stefan , Adhikari, Raju , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 92, no. 2 (2013), p. 1484-1496
- Full Text: false
- Reviewed:
- Description: The physicochemical properties of lentil starch were measured and linked up with its functional properties and compared with those of corn and potato starches. The amylose content of lentil starch was the highest among these starches. The crystallinity and gelatinization enthalpy of lentil starch were the lowest among these starches. The high amylose: amylopectin ratio in lentil starch resulted into low crystallinity and gelatinization enthalpy. Gelatinization and pasting temperatures of lentil starch were in between those of corn and potato starches. Lentil starch gels showed the highest storage modulus, gel strength and pasting viscosity than corn and potato starch gels. Peleg's model was able to predict the stress relaxation data of these starches well (R2 > 0.98). The elastic modulus of lentil starch gel was less frequency dependent and higher in magnitude at high temperature (60 °C) than at lower temperature (10 °C). Lentil starch is suitable where higher gel strengthened pasting viscosity are desired. © 2012 Elsevier Ltd.
- Description: 2003011035
Effects of partial gelatinization on structure and thermal properties of corn starch after spray drying
- Authors: Fu, Zong-qiang , Wang, Li-jun , Li, Dong , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 88, no. 4 (2012), p. 1319-1325
- Full Text: false
- Reviewed:
- Description: 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 m 3/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. © 2012 Elsevier Ltd. All rights reserved.
Suspensions of vacuum-freeze dried starch nanoparticles : Influence of NaCl on their rheological properties
- Authors: Shi, Aimin , Wang, Li-jun , Li, Dong , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 94, no. 2 (2013), p. 782-790
- Full Text: false
- Reviewed:
- Description: 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 ((R
- Description: 2003010855
The effect of addition of flaxseed gum on the rheological behavior of mixed flaxseed gum-casein gels
- Authors: Li, XinYu , Li, Dong , Wang, Li-jun , Wu, Min , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 88, no. 4 (2012), p. 1214-1220
- Full Text: false
- Reviewed:
- Description: The effect of addition of flaxseed gum on the rheological properties of mixed flaxseed gum-casein gels (flaxseed gum concentration: 0.1-0.5%, w/w and casein concentration: 15-23%, w/w) was studied using both small amplitude oscillatory and steady shear measurements. It was found that the storage (G′) and loss (G″) moduli increased with the increase in the flaxseed gum concentration. Both the experimentally determined G′ and G″ values were fitted well by Power Law model. The addition of flaxseed gum increased the Power Law constants (K′ and K″) at the same time the frequency exponents (n′ and n″) decreased. The G′, G″ of the mixed flaxseed gum-casein gels decreased with increase in temperature. The gelling temperature was found to increase linearly with the increase in flaxseed gum concentration. The apparent viscosities increased with increase in the flaxseed gum and casein concentrations, and were also fitted well by Power Law model. © 2012 Elsevier Ltd. All rights reserved.
The effect of annealing and cryoprotectants on the properties of vacuum-freeze dried starch nanoparticles
- Authors: Shi, Aimin , Wang, Li-Jun , Li, Dong , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 88, no. 4 (2012), p. 1334-1341
- Full Text: false
- Reviewed:
- Description: 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 (T-g), 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 T-g of these nanoparticles varied from 52 degrees C to 57 degrees 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. (C) 2012 Elsevier Ltd. All rights reserved.
Raman, infrared and XPS study of bamboo phytoliths after chemical digestion
- Authors: Watling, Kym , Parr, Jeffrey , Rintoul, Llew , Brown, Christopher , Sullivan, Leigh
- Date: 2011
- Type: Text , Journal article
- Relation: Spectrochimica Acta - Part A : Molecular and Biomolecular Spectroscopy Vol. 80, no. 1 (2011), p. 106-111
- Full Text: false
- Reviewed:
- Description: Raman, infrared and X-ray photoelectron spectroscopies have been used to examine the effect of various chemical digestion methods on the composition of bamboo phytoliths. Intact bilobate phytoliths, suitable for interrogation by Raman microprobe analysis, were isolated by a microwave wet ashing technique using hydrogen peroxide with nitric and hydrochloric acids. The occluded phytolith carbon presented evidence of cellulose, lignin and carboxylic acids. Nitrate from the nitric acid used in the digestion was observed in homogenized samples of the isolated phytoliths; in addition to nitrogen of plant origin occluded within the phytolith, which was observed as amine nitrogen and ammonia. Intact bilobate phytoliths were not observed following an exothermic hydrogen peroxide/sulfuric acid digest, suggesting that these structures ruptured during this digestion procedure. The silicate network was significantly altered during isolation using the exothermic hydrogen peroxide/sulfuric digest, with surface hydroxyls undergoing condensation to form a SiO 3 ring structure. © 2011 Elsevier B.V. All rights reserved.