Enhancing antioxidant availability in wheat grains from plants grown under seawater stress in response to microalgae extract treatments

BACKGROUND: The present study was designed to investigate the enhanced antioxidant capacity of whole grains from wheat plants grown under seawater stress in response to microalgae extract treatment. RESULTS: The total carotenoid (TCAR), tocopherol (TOC), phenolic (TPC), and protein (PC) contents in whole grains of wheat plants irrigated with 10% and 20% (v/v) seawater (SW) in response to water extracts of microalgae Spirulina maxima (SME) and Chlorella ellipsoida (CEE) as well as exogenous plant growth enhancers of ascorbic acid and benzyladenine treatments were measured. The results showed that the levels of enhanced TCAR (range 0.08–0.14 g kg^?1), TOC (range 0.05–0.12 g kg^?1), TPC (range 0.80–2.96 g kg^?1) and PC (range 93.4–137.9 g kg^?1) in wheat grains of plants irrigated with 10% and 20% SW were significantly increased in response to SME and CEE treatments. Evaluation of antioxidant activity of ethanolic extracts of grains of SW‐stressed plants indicated that DPPH and TBAS radical scavenging activity was significantly increased in response to SME and CEE treatments and coincided with the increase in levels of antioxidant compounds present in each extract. The electrophoretic profiles of the grains of proteins of treated samples exhibited quite different patterns from those in control samples. CONCLUSION: The results suggest that the application of algal extracts to wheat plants irrigated with SW is useful for improvement of salinity tolerance. This effect can be triggered by the stimulation of antioxidant components and protein content. Copyright © 2009 Society of Chemical Industry     

Tethered methanol droplet combustion in carbon-dioxide enriched environment under microgravity conditions

Tethered methanol droplet combustion in carbon dioxide enriched environment is simulated using a transient one-dimensional spherosymmetric droplet combustion model that includes the effects of tethering. A priori numerical predictions are compared against recent experimental data. The numerical predictions compare favorably with the experimental results and show significant effects of tethering on the experimental observations. The presence of a relatively large quartz fiber tether increases the burning rate significantly and hence decreases the extinction diameter. The simulations further show that the extinction diameter depends on both the initial droplet diameter and the ambient concentration of carbon dioxide. Increasing the droplet diameter and ambient carbon dioxide concentration both of them lead to a decrease in the burning rate and increase in the extinction diameter. The influence of ambient carbon dioxide concentration on extinction shows a sharp transition in extinction for larger size droplets (d_o > 1.5 mm) due to a change in the mode of extinction from diffusive to radiative control. In addition predictions from the numerical model is compared against a recently developed simplified theoretical model for predicting extinction diameter for methanol droplets, where the presence and heat transfer contribution of the tether is not taken into account implicitly. The numerical results suggest some limitation in the theoretical modeling assumptions for favorable comparisons with the experimental data.     

On the extinction characteristics of alcohol droplet combustion under microgravity conditions – A numerical study

Quasi-steady burning and extinction of droplets are of interest from both fundamental and application viewpoints. The latter is related to combustor performance and fire safety issues in reduced gravity environments. Influences of diluent in the atmosphere on isolated droplet combustion characteristics including extinction provide insights to fire extinguishment phenomena and the effectiveness of various diluents as fire suppressants. Extinction of pure methanol and methanol–water droplets ranging from 1.5 to 7 mm size, for varying levels of ambient carbon-dioxide, helium and oxygen concentration – burning in a quiescent microgravity environment were studied numerically to compare the effectiveness of fire suppressant diluent selection and determining the limiting oxygen index. The results show distinct regimes of diffusive and radiative extinction. The transition from diffusive to radiative extinction is strongly influenced by the ambient diluent selection, especially by carbon dioxide concentration. Results for helium as the diluent showed increased burning rate and extinction due to diffusive heat loss. An “extinction characteristic” correlation is proposed that depends on burning rate, ambient diffusivity and flame standoff ratio. Recent methanol droplet experiments conducted over a wide range of operating conditions onboard the International Space Station were found to yield results that agree well with the proposed “extinction characteristic” correlation.     

Numerical analysis of an OPTR: Optimization for space applications

A numerical study is reported here for the investigation of the flow and heat transfer processes in a co-axial type single stage orifice type pulse tube refrigerator (OPTR). The OPTR is driven by a cyclically moving piston at one end of the system with helium as the working fluid. The regenerator and the various heat exchangers are modeled as porous media and a thermal non-equilibrium model is applied in these regions. The simulations reveal interesting steady-periodic flow patterns that develop in the pulse tube due to the fluctuations caused by the piston and the presence of the inertance tube. When the secondary flow patterns are well-developed, they help isolate the cold and hot ends of the pulse tube and create a thermal buffer zone at the center of the pulse tube, enhancing the performance of the OPTR.     

Scanning electron microscopy and morphometric analysis of superficial corneal epithelial cells in dromedary camel (Camelus dromedarius)

It is likely that superficial corneal epithelial cells (SCECs) of the dromedary camels have a significant role in their survival at arid and semiarid regions. To the best of our knowledge, SCECs of camels' eyes have not been characterized previously using scanning electron microscopy (SEM), combined with morphometric analysis. Therefore, in the current study, we aim to describe the shape, topographical distribution, and density of SCECs associated with morphometric analysis using SEM. Twelve healthy adult camels' corneas were obtained immediately after slaughter. Each cornea has been divided into nine parts: central (C), middle dorsal (MD), middle ventral (MV), middle nasal (MN), middle temporal (MT), peripheral dorsal (PD), peripheral ventral (PV), peripheral nasal (PN), and peripheral temporal (PT). SCECs were distinguished and characterized into light, medium, and dark mosaics. The polygonal cells have been externally covered with microplicae that were more numerous above the light cells. The topographic distribution of light, medium, and dark cells revealed a well-defined concentration of light cells in excess of other cells in all parts as follows: PV (92.5%), PN (78.5%), MN (78%), MT (74.7%), PD (73.8%), PT (70.7%), MV (68.7%), MD (66.3%), and C (19.3%). The PV part recorded the highest density of light cells, while the C portion showed the lowest density for the same cells. We concluded that the light cells extensively predominate in all parts of the camels' cornea except the C part, indicating an adaptive modification to the harsh environment. Additionally, the PV and PN parts represent the permanent and endogenous source as well as a proliferative reserve for SCECs in dromedary camel.     

Effect of amino acids on the composition and properties of extruded mixtures of wheat flour and glucose

Wheat flour was extruded at 100-120 degrees C with 5% D-glucose or mixtures of 5% D-glucose and 0.5% or 2.0% of L-alanine, L-leucine, L-lysine, L-threonine or L-cysteine. The extent of browning was only moderate, and yellow and red pigments were produced. The odour intensity increased with the addition of either glucose or a mixture of glucose and amino acids; the odour was not significantly intensive according to sensory acceptancy analysis. The odour profile was influenced by the structure of amino acid present in the extruded material. The addition of D-glucose increased the production of furan derivatives, and in lesser degree, of pyrazines in the extruded product. The pyrazine content increased with the addition of amino acids, except cysteine which enhanced the production of sulphur compounds instead of pyrazines. The composition of the pyrazine fraction varied depending on the amino acid added. Pretreatment of D-glucose with an amino acid in aqueous solution affected the composition of volatiles, but it did not significantly enhance the pyrazine production.     

Acceptability and functional properties of restructured roast from frozen pre-rigor injected beef

Restructured beef roasts, made to a standardized formulation, were prepared using the following types of meat that had been stored at - 18 °C for 5 or 10 weeks: grass-fed bull beef pre-rigor injected with a salt/phosphate brine; uninjected grass-fed bull beef; uninjected grain-fed beef; a 50:50 blend of pre-rigor injected grass-fed bull beef and grain-fed beef; and a 50:50 blend of uninjected grass-fed bull beef and grain-fed beef. After frozen storage, pre-rigor injected beef had a higher (p < 0.05) ultimate pH than uninjected beef . Grain-fed beef had the lowest ultimate pH. Roasts made from pre-rigor injected beef were redder (higher Hunter a(?) values) than roasts made with uninjected beef (p < 0.05). Roasts made from grain-fed beef were lighter and looked more cooked (higher L(?) and lower a(?) values respectively) than those made with grass-fed beef. Extending frozen storage to 10 weeks decreased the cook yield (p < 0.05), peak force (p < 0.001) and extensibility (p < 0.05). Consumer panellists preferred (p < 0.05) roasts made from pre-rigor injected beef for tenderness, juiciness and overall acceptability compared with roasts made from uninjected beef.     

Initial chilling rate of pre-rigor beef muscles as an indicator of colour of thawed meat

The effect of three rigor temperatures and two muscles of different fibre composition on the colour of thawed meat were determined. Within 45 min post-mortem, m. semitendinosus (ST) and m. biceps femoris (BF) from unstimulated heifer sides were held at 0, 10 and 35°C until they entered rigor. The rate of pH fall was higher at 35°C than at 0 and 10°C; and the pH values were lower (first 12 h post mortem) in the ST than the BF. Hunter L*, a* and b* and the hue angle increased with increasing rigor temperature (P<0.001). The ST was lighter and yellower and had greater hue angle than the BF. Colour parameters were plotted against the rate of muscle cooling in the first hour post mortem and linear regression lines were fitted to the data and equations were derived that gave a good indication of the colour and colour stability of the muscles as meat.