Controlling the rheological properties of wheat starch gels using Lepidium perfoliatum seed gum in steady and dynamic shear.

In the present work, the influence of Lepidium perfoliatum seed gum (LPSG) addition in varied concentrations (0%, 0.25%, 0.5%, 0.75% and 1%, w/w) on dynamic and steady shear rheological properties of wheat starch dispersion (4%, /w) was examined. Comparison of the values of dynamic (G', G″, τy, τf, tan δ), shear-dependent (ηa,50, η0, η∞, τ, m) and time-dependent (ηa,3s, k, η0, η∞) rheological parameters of the WS-LPSG mixtures with WS alone, indicated that the viscoelastic and flow properties of the mixtures were greatly affected by the addition of LPSG. According to the standard method provided by the National Dysphagia Diet (NDD), the WS and WS-LPSG gels were placed in the category of nectar-like (WS), honey-like (WS-0.25%LPSG, WS-0.5%LPSG and WS-0.75%LPSG) and spoon-thick (WS-1%LPSG) viscosity. In the simulated oral condition (SOC), the presence of saliva caused the increase of k value (10-81%), whilst decreased the values of η0 (43-95%) and η∞ (68-96%). As the concentration of LPSG increased, less decrease in value of ηa,3s in the SOC was observed. The results of present study demonstrated the feasibility of manipulating the viscosity of the WS gels by addition of LPSG to be suitable for the individuals with varying degrees of swallowing difficulty.

Fabrication and characterization of hybrid sodium montmorillonite/TiO2 reinforced cross-linked wheat starch-based nanocomposites.

In this work, a novel cross-linked wheat starch (CLWS)-based ternary nanocomposite films with incorporation of sodium montmorillonite (Na-MMT) (3%-7% wt.) and titanium dioxide (TiO2) (1%-4% wt.) nanoparticles were fabricated using casting method. CLWS film exhibited better physical, mechanical and thermal properties compared with the native wheat starch (NWS) film. Incorporation of the nanoparticles into the film solution resulted in a decrease in water vapor permeability (WVP), water solubility (WS), moisture content (MC) of the films, whereas density increased. Nano-TiO2 blocked the UV light effectively and >99% of UV was removed by the film containing 4% TiO2. Affecting by the addition of nanomaterials, the amounts of ultimate tensile strength (UTS) and Young's modulus (YM) values enhanced, while elongation at break (EB) ones diminished. By the Furrier transform infrared (FT-IR) spectroscopy, the creation of new hydrogen bonds between the starch's hydroxyl groups and nanomaterials was confirmed. Formation of a completely exfoliated structure for CLWS/Na-MMT/TiO2 nanocomposites was proved by XRD. SEM micrographs exhibited appropriate dispersion of nanomaterials through the films surface particularly at lower concentrations. The thermogravimetric analysis (TGA) results revealed that the addition of nanomaterials especially TiO2 improved the thermal stability of the nanocomposite films.

The effects of thoracic aortic cross-clamping and declamping on visceral organ blood flow.

Blood flow was measured using radioactive microspheres in 11 macaque monkeys 1) before hemorrhage shock, 2) after onset of shock, 3) after aortic cross-clamping and resuscitation, and 4) after release of the cross-clamp and stabilization. Hemodynamic parameters (cardiac output, arterial, right atrial and left atrial pressure) and blood gases were also monitored. Total abdominal organ flow fell with hemorrhage and fell further with aortic clamping. Reinfusion of shed volume did not restore abdominal organ flow (4.7% baselines) but increased LAP and cardiac output to the upper body. Release of the cross-clamp produced profound acidosis that was treated effectively with NcHCO3. After stabilization of blood, flow to kidney remained low (49% baseline) although intestinal flow was increased threefold (320% of baseline). It is clear that thoracic aortic cross-clamping in shock further compromises already reduced visceral blood flow and may contribute to the problem of ischemic multiple organ failure after resuscitation from hemorrhagic shock.