The optimal conditions for the extraction of lignans from flaxseed were determined. A second-order regression for rotation-orthogonal composite design was used to investigate the effects of three independent variables, namely ethanol concentration (%), extraction temperature (℃), and extraction time (h) on the response, the acquired ratio of lignans. The independent variables were coded at five levels and their actual values selected on the basis of results of single-factor experiment. The second-order regression for rotation-orthogonal composite design consisted of 23 experimental points and 9 replications at the central point. Data were analyzed using MATLAB software. The results indicated that acquired ratio of lignans might be beyond 8% at a probability of 95% in the range of ethanol concentration: 56.6-83.4%, extraction time: 26.7-27.9 h, extraction temperature: 38.7-40.1℃. And the optimal extraction conditions were ethanol concentration of 70%, extraction time of 28h and extraction temperature of 40℃ according to the analysis of response surface. In this condition, the experimental acquired ratio of lignans was 8.975% (w/w; lignans/defatted flaxseed powder), which is close to the predicted value (9.316%).

Flaxseed gum solutions were extracted and dried by different methods: ethanol precipitation, freeze drying, 105℃ oven drying, 80℃ 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 G0 and G00 values. In creep-recovery tests, the data were modeled by Berger's model. The E2 and g1 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.

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.

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 (ga) and dynamic moduli (G0 and G00) 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.

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 0.4 g/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 0.2 g/g in different media. However, the changes of these three aspects became inconspicuous when TSTP concentration increased to 0.4 g/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.

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℃ to 105.0℃ and from -60.0℃ to 160.0℃. The gelatinization temperature of buckwheat flour was between 60℃ and 85℃ and it decreased while the water content increased. Isolated buckwheat starch showed a narrower gelatinization range from 60℃ to 75℃. To, Tp, Tc and DH 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.

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℃. The spectra of storage modulus (G0), loss modulus (G00), and loss factor (tand) 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 (G0), loss modulus (G00), and loss factor (tand) were measured for the second and third time after two and seven days, respectively. The peaks of loss factor (tand) appeared at 59.81±1.86℃ and 95.96±1.67℃ after two-day-storage, but only one peak appeared at 85.46±5.50℃ after seven days. A shifting trend from higher to lower temperature for loss factor was observed after seven days.

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℃, 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%.

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 (DHgel) 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.

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℃ 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 0.177C/MPa and 0.186C/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.